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177 <h1>Command-line Options</h1>
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href="command-line-options.html#morph">‑morph</a> <span class="bull"> • </span> <a href="command-line-options.html#morphology">‑morphology</a> <span class="bull"> • </span> <a href="command-line-options.html#mosaic">‑mosaic</a> <span class="bull"> • </span> <a href="command-line-options.html#motion-blur">‑motion‑blur</a> <span class="bull"> • </span> <a href="command-line-options.html#name">‑name</a> <span class="bull"> • </span> <a href="command-line-options.html#negate">‑negate</a> <span class="bull"> • </span> <a href="command-line-options.html#noise">‑noise</a> <span class="bull"> • </span> <a href="command-line-options.html#normalize">‑normalize</a> <span class="bull"> • </span> <a href="command-line-options.html#opaque">‑opaque</a> <span class="bull"> • </span> <a href="command-line-options.html#ordered-dither">‑ordered‑dither</a> <span class="bull"> • </span> <a href="command-line-options.html#orient">‑orient</a> <span class="bull"> • </span> <a 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href="command-line-options.html#posterize">‑posterize</a> <span class="bull"> • </span> <a href="command-line-options.html#precision">‑precision</a> <span class="bull"> • </span> <a href="command-line-options.html#preview">‑preview</a> <span class="bull"> • </span> <a href="command-line-options.html#print">‑print</a> <span class="bull"> • </span> <a href="command-line-options.html#process">‑process</a> <span class="bull"> • </span> <a href="command-line-options.html#profile">‑profile</a> <span class="bull"> • </span> <a href="command-line-options.html#quality">‑quality</a> <span class="bull"> • </span> <a href="command-line-options.html#quantize">‑quantize</a> <span class="bull"> • </span> <a href="command-line-options.html#quiet">‑quiet</a> <span class="bull"> • </span> <a href="command-line-options.html#radial-blur">‑radial‑blur</a> <span class="bull"> • </span> <a href="command-line-options.html#raise">‑raise</a> <span class="bull"> • </span> <a href="command-line-options.html#random-threshold">‑random‑threshold</a> <span class="bull"> • </span> <a href="command-line-options.html#red-primary">‑red‑primary</a> <span class="bull"> • </span> <a href="command-line-options.html#regard-warnings">‑regard‑warnings</a> <span class="bull"> • </span> <a href="command-line-options.html#region">‑region</a> <span class="bull"> • </span> <a href="command-line-options.html#remap">‑remap</a> <span class="bull"> • </span> <a href="command-line-options.html#remote">‑remote</a> <span class="bull"> • </span> <a href="command-line-options.html#render">‑render</a> <span class="bull"> • </span> <a href="command-line-options.html#repage">‑repage</a> <span class="bull"> • </span> <a href="command-line-options.html#resample">‑resample</a> <span class="bull"> • </span> <a href="command-line-options.html#resize">‑resize</a> <span class="bull"> • </span> <a href="command-line-options.html#respect-parentheses">‑respect‑parentheses</a> <span class="bull"> • </span> <a href="command-line-options.html#reverse">‑reverse</a> <span class="bull"> • </span> <a href="command-line-options.html#roll">‑roll</a> <span class="bull"> • </span> <a href="command-line-options.html#rotate">‑rotate</a> <span class="bull"> • </span> <a href="command-line-options.html#sample">‑sample</a> <span class="bull"> • </span> <a href="command-line-options.html#sampling-factor">‑sampling‑factor</a> <span class="bull"> • </span> <a href="command-line-options.html#scale">‑scale</a> <span class="bull"> • </span> <a href="command-line-options.html#scene">‑scene</a> <span class="bull"> • </span> <a href="command-line-options.html#screen">‑screen</a> <span class="bull"> • </span> <a href="command-line-options.html#seed">‑seed</a> <span class="bull"> • </span> <a href="command-line-options.html#segment">‑segment</a> <span class="bull"> • </span> <a href="command-line-options.html#selective-blur">‑selective‑blur</a> <span class="bull"> • </span> <a href="command-line-options.html#separate">‑separate</a> <span class="bull"> • </span> <a href="command-line-options.html#sepia-tone">‑sepia‑tone</a> <span class="bull"> • </span> <a href="command-line-options.html#set">‑set</a> <span class="bull"> • </span> <a href="command-line-options.html#shade">‑shade</a> <span class="bull"> • </span> <a href="command-line-options.html#shadow">‑shadow</a> <span class="bull"> • </span> <a href="command-line-options.html#shared-memory">‑shared‑memory</a> <span class="bull"> • </span> <a href="command-line-options.html#sharpen">‑sharpen</a> <span class="bull"> • </span> <a href="command-line-options.html#shave">‑shave</a> <span class="bull"> • </span> <a href="command-line-options.html#shear">‑shear</a> <span class="bull"> • </span> <a href="command-line-options.html#sigmoidal-contrast">‑sigmoidal‑contrast</a> <span class="bull"> • </span> <a href="command-line-options.html#silent">‑silent</a> <span class="bull"> • </span> <a href="command-line-options.html#similarity-threshold">‑similarity‑threshold</a> <span class="bull"> • </span> <a href="command-line-options.html#size">‑size</a> <span class="bull"> • </span> <a href="command-line-options.html#sketch">‑sketch</a> <span class="bull"> • </span> <a href="command-line-options.html#smush">‑smush</a> <span class="bull"> • </span> <a href="command-line-options.html#snaps">‑snaps</a> <span class="bull"> • </span> <a href="command-line-options.html#solarize">‑solarize</a> <span class="bull"> • </span> <a href="command-line-options.html#sparse-color">‑sparse‑color</a> <span class="bull"> • </span> <a href="command-line-options.html#splice">‑splice</a> <span class="bull"> • </span> <a href="command-line-options.html#spread">‑spread</a> <span class="bull"> • </span> <a href="command-line-options.html#statistic">‑statistic</a> <span class="bull"> • </span> <a href="command-line-options.html#stegano">‑stegano</a> <span class="bull"> • </span> <a href="command-line-options.html#stereo">‑stereo</a> <span class="bull"> • </span> <a href="command-line-options.html#stretch">‑stretch</a> <span class="bull"> • </span> <a href="command-line-options.html#strip">‑strip</a> <span class="bull"> • </span> <a href="command-line-options.html#stroke">‑stroke</a> <span class="bull"> • </span> <a href="command-line-options.html#strokewidth">‑strokewidth</a> <span class="bull"> • </span> <a href="command-line-options.html#style">‑style</a> <span class="bull"> • </span> <a href="command-line-options.html#subimage-search">‑subimage‑search</a> <span class="bull"> • </span> <a href="command-line-options.html#swap">‑swap</a> <span class="bull"> • </span> <a href="command-line-options.html#swirl">‑swirl</a> <span class="bull"> • </span> <a href="command-line-options.html#synchronize">‑synchronize</a> <span class="bull"> • </span> <a href="command-line-options.html#taint">‑taint</a> <span class="bull"> • </span> <a href="command-line-options.html#text-font">‑text‑font</a> <span class="bull"> • </span> <a href="command-line-options.html#texture">‑texture</a> <span class="bull"> • </span> <a href="command-line-options.html#threshold">‑threshold</a> <span class="bull"> • </span> <a href="command-line-options.html#thumbnail">‑thumbnail</a> <span class="bull"> • </span> <a href="command-line-options.html#tile">‑tile</a> <span class="bull"> • </span> <a href="command-line-options.html#tile-offset">‑tile‑offset</a> <span class="bull"> • </span> <a href="command-line-options.html#tint">‑tint</a> <span class="bull"> • </span> <a href="command-line-options.html#title">‑title</a> <span class="bull"> • </span> <a href="command-line-options.html#transform">‑transform</a> <span class="bull"> • </span> <a href="command-line-options.html#transparent">‑transparent</a> <span class="bull"> • </span> <a href="command-line-options.html#transparent-color">‑transparent‑color</a> <span class="bull"> • </span> <a href="command-line-options.html#transpose">‑transpose</a> <span class="bull"> • </span> <a href="command-line-options.html#transverse">‑transverse</a> <span class="bull"> • </span> <a href="command-line-options.html#treedepth">‑treedepth</a> <span class="bull"> • </span> <a href="command-line-options.html#trim">‑trim</a> <span class="bull"> • </span> <a href="command-line-options.html#type">‑type</a> <span class="bull"> • </span> <a href="command-line-options.html#undercolor">‑undercolor</a> <span class="bull"> • </span> <a href="command-line-options.html#unique-colors">‑unique‑colors</a> <span class="bull"> • </span> <a href="command-line-options.html#units">‑units</a> <span class="bull"> • </span> <a href="command-line-options.html#unsharp">‑unsharp</a> <span class="bull"> • </span> <a href="command-line-options.html#update">‑update</a> <span class="bull"> • </span> <a href="command-line-options.html#verbose">‑verbose</a> <span class="bull"> • </span> <a href="command-line-options.html#version">‑version</a> <span class="bull"> • </span> <a href="command-line-options.html#view">‑view</a> <span class="bull"> • </span> <a href="command-line-options.html#vignette">‑vignette</a> <span class="bull"> • </span> <a href="command-line-options.html#virtual-pixel">‑virtual‑pixel</a> <span class="bull"> • </span> <a href="command-line-options.html#visual">‑visual</a> <span class="bull"> • </span> <a href="command-line-options.html#watermark">‑watermark</a> <span class="bull"> • </span> <a href="command-line-options.html#wave">‑wave</a> <span class="bull"> • </span> <a href="command-line-options.html#weight">‑weight</a> <span class="bull"> • </span> <a href="command-line-options.html#white-point">‑white‑point</a> <span class="bull"> • </span> <a href="command-line-options.html#white-threshold">‑white‑threshold</a> <span class="bull"> • </span> <a href="command-line-options.html#window">‑window</a> <span class="bull"> • </span> <a href="command-line-options.html#window-group">‑window‑group</a> <span class="bull"> • </span> <a href="command-line-options.html#write">‑write</a> ] </p>
181 <div class="doc-section">
183 <p>Below is list of command-line options recognized by the ImageMagick <a href="command-line-tools.html">command-line
184 tools</a>. If you want a description of a particular option, click on the
185 option name in the navigation bar above and you will go right to it. Unless
186 otherwise noted, each option is recognized by the commands <a href="convert.html">convert</a>, <a href="mogrify.html">mogrify</a>.</p>
188 <div style="margin: auto;">
189 <h4><a id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4>
192 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Adaptively blur pixels, with decreasing effect near edges.</td><td style="text-align:right;"></td></tr></table>
194 <p>A Gaussian operator of the given radius and standard deviation (<em class="arg">sigma</em>) is used. If <em class="arg">sigma</em> is not given it
197 <div style="margin: auto;">
198 <h4><a id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4>
201 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Resize the image using data-dependent triangulation.</td><td style="text-align:right;"></td></tr></table>
203 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <a href="command-line-options.html#adaptive-resize">-adaptive-resize</a>
204 option defaults to data-dependent triangulation. Use the <a href="command-line-options.html#filter">-filter</a> to choose a different resampling algorithm.
205 Offsets, if present in the geometry string, are ignored, and the <a href="command-line-options.html#gravity">-gravity</a> option has no effect.</p>
207 <div style="margin: auto;">
208 <h4><a id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4>
211 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Adaptively sharpen pixels, with increasing effect near edges.</td><td style="text-align:right;"></td></tr></table>
213 <p>A Gaussian operator of the given radius and standard deviation (<em class="arg">sigma</em>) is used. If <em class="arg">sigma</em> is not given it
216 <div style="margin: auto;">
217 <h4><a id="adjoin"></a>-adjoin</h4>
220 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Join images into a single multi-image file.</td><td style="text-align:right;"></td></tr></table>
222 <p>This option is enabled by default. An attempt is made to save all images of
223 an image sequence into the given output file. However, some formats, such as
224 JPEG and PNG, do not support more than one image per file, and in that case
225 ImageMagick is forced to write each image as a separate file. As such, if
226 more than one image needs to be written, the filename given is modified by
227 adding a <a href="command-line-options.html#scene">-scene</a> number before the suffix, in order to
228 make distinct names for each image. </p>
230 <p>Use <a href="command-line-options.html#adjoin">+adjoin</a> to force each image to be written to
231 separate files, whether or not the file format allows multiple images per file
232 (for example, GIF, MIFF, and TIFF). </p>
234 <p>Including a C-style integer format string in the output filename will
235 automagically enable <a href="command-line-options.html#adjoin">+adjoin</a> and are used to specify
236 where the <a href="command-line-options.html#scene">-scene</a> number is placed in the filenames. These
237 strings, such as '<code>%d</code>' or '<code>%03d</code>', are familiar to those
238 who have used the standard <code>printf()</code>' C-library function. As an
239 example, the command</p>
241 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert logo: rose: -morph 15 my%02dmorph.jpg</span></p>
242 <p>will create a sequence of 17 images (the two given plus 15 more created by
243 <a href="command-line-options.html#morph">-morph</a>), named: my00morph.jpg, my01morph.jpg,
244 my02morph.jpg, ..., my16morph.jpg. </p>
246 <p>In summary, ImageMagick tries to write all images to one file, but will
247 save to multiple files, if any of the following conditions exist...</p>
249 <li>the output image's file format does not allow multi-image files,</li>
250 <li>the <a href="command-line-options.html#adjoin">+adjoin</a> option is given, or</li>
251 <li>a printf() integer format string (eg: "%d") is present in the output
256 <div style="margin: auto;">
257 <h4><a id="affine"></a>-affine
258 <em class="arg">s<sub>x</sub></em>,<em class="arg">r<sub>x</sub></em>,<em class="arg">r<sub>y</sub></em>,<em class="arg">s<sub>y</sub></em>[,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em>]</h4>
261 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the drawing transformation matrix for combined rotating and scaling.</td><td style="text-align:right;"></td></tr></table>
263 <p>This option sets a transformation matrix, for use by subsequent <a href="command-line-options.html#draw">-draw</a> or <a href="command-line-options.html#transform">-transform</a> options. </p>
265 <p>The matrix entries are entered as comma-separated numeric values either in
266 quotes or without spaces. </p>
268 <p>Internally, the transformation matrix has 3x3 elements, but three of them
269 are omitted from the input because they are constant. The new (transformed)
270 coordinates (<em class="arg">x'</em>, <em class="arg">y'</em>) of a pixel at
271 position (<em class="arg">x</em>, <em class="arg">y</em>) in the original
272 image are calculated using the following matrix equation.</p>
275 <img alt="affine transformation" src="../images/affine.png"></img>
278 <p> The size of the resulting image is that of the smallest rectangle that
279 contains the transformed source image. The parameters <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em>
280 subsequently shift the image pixels so that those that are moved out of the
281 image area are cut off.</p>
283 <p>The transformation matrix complies with the left-handed pixel coordinate
284 system: positive <em class="arg">x</em> and <em class="arg">y</em> directions
285 are rightward and downward, resp.; positive rotation is clockwise.</p>
287 <p> If the translation coefficients <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are omitted they default to 0,0. Therefore,
288 four parameters suffice for rotation and scaling without translation.</p>
290 <p>Scaling by the factors <em class="arg">s<sub>x</sub></em> and <em class="arg">s<sub>y</sub></em> in the <em>x</em> and <em>y</em> directions,
291 respectively, is accomplished with the following.</p>
293 <p>See <a href="command-line-options.html#transform">-transform</a>, and the <a href="command-line-options.html#distort">-distort</a> method '<code>Affineprojection</code> for more
297 <p class="crtsnip"> -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em> </p>
299 <p>Translation by a displacement (<em class="arg">t<sub>x</sub></em>, <em class="arg">t<sub>y</sub></em>) is accomplished like so:</p>
302 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em>
305 <p>Rotate clockwise about the origin (the upper left-hand corner) by an angle
306 <em>a</em> by letting <em>c</em> = cos(<em>a</em>), <em>s</em>
307 = sin(<em>a</em>), and using the following.</p>
310 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em>
313 <p>The cumulative effect of a sequence of <a href="command-line-options.html#affine">-affine</a>
314 transformations can be accomplished by instead by a single <a href="command-line-options.html#affine">-affine</a> operation using the matrix equal to the product of the matrices
315 of the individual transformations.</p>
317 <p>An attempt is made to detect near-singular transformation matrices. If the
318 matrix determinant has a sufficiently small absolute value it is rejected.</p>
320 <div style="margin: auto;">
321 <h4><a id="alpha"></a>-alpha <em class="arg">type</em></h4>
324 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Gives control of the alpha/matte channel of an image.</td><td style="text-align:right;"></td></tr></table>
326 <p>Used to set a flag on an image indicating whether or not to use existing alpha
327 channel data, to create an alpha channel, or to perform other operations on the alpha channel. Choose the argument <em class="arg">type</em> from the list below.</p>
333 <th align="left" style="width: 8%">type</th>
334 <th align="left">Description</th>
338 <td valign="top"><code>Activate</code> or <code>On</code></td>
340 Enable the image's transparency channel. Note normally <code>Set</code>
341 should be used instead of this, unless you specifically need to
342 preserve existing (but specifically turned <code>Off</code>) transparency
346 <td valign="top"><code>Deactivate</code> or <code>Off</code></td>
348 Disables the image's transparency channel. Does not delete or change the
349 existing data, just turns off the use of that data.</td></tr>
352 <td valign="top"><code>Set</code></td>
354 Activates the alpha/matte channel. If it was previously turned off
355 then it also resets the channel to opaque. If the image already had
356 the alpha channel turned on, it will have no effect.</td></tr>
359 <td valign="top"><code>Opaque</code></td>
361 Enables the alpha/matte channel and forces it to be fully opaque.
365 <td valign="top"><code>Transparent</code></td>
367 Activates the alpha/matte channel and forces it to be fully
368 transparent. This effectively creates a fully transparent image the
369 same size as the original and with all its original RGB data still
370 intact, but fully transparent. </td></tr>
373 <td valign="top"><code>Extract</code></td>
375 Copies the alpha channel values into all the color channels and turns
376 '<code>Off</code>' the the image's transparency, so as to generate
377 a gray-scale mask of the image's shape. The alpha channel data is left
378 intact just deactivated. This is the inverse of '<code>Copy</code>'.
382 <td valign="top"><code>Copy</code></td>
384 Turns '<code>On</code>' the alpha/matte channel, then copies the
385 gray-scale intensity of the image, into the alpha channel, converting
386 a gray-scale mask into a transparent shaped mask ready to be colored
387 appropriately. The color channels are not modified. </td></tr>
390 <td valign="top"><code>Shape</code></td>
392 As per '<code>Copy</code>' but also colors the resulting shape mask with
393 the current background color. That is the RGB color channels is
394 replaced, with appropriate alpha shape.
398 <td valign="top"><code>Remove</code></td>
400 Composite the image over the background color.
404 <td valign="top"><code>Background</code></td>
406 Set any fully-transparent pixel to the background color, while leaving
407 it fully-transparent. This can make some image file formats, such as
408 PNG, smaller as the RGB values of transparent pixels are more uniform,
409 and thus can compress better.
414 <p>Note that while the obsolete <code>+matte</code> operation was the
415 same as "<code><a href="command-line-options.html#alpha">-alpha</a> Off</code>", the <code>
416 >-matte</code> operation was the same as "<code><a href="command-line-options.html#alpha">-alpha</a>
417 Set</code>" and not "<code><a href="command-line-options.html#alpha">-alpha</a> On</code>". </p>
420 <div style="margin: auto;">
421 <h4><a id="annotate"></a>
422 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br></br>
423 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br></br> -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> {+-}<em class="arg">t<sub>x</sub></em>{+-}<em class="arg">t<sub>y</sub></em> <em class="arg">text</em></h4>
426 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Annotate an image with text.</td><td style="text-align:right;"></td></tr></table>
428 <p>This is a convenience for annotating an image with text. For more precise
429 control over text annotations, use <a href="command-line-options.html#draw">-draw</a>.</p>
432 <p>The values <em class="arg">Xdegrees</em> and <em class="arg">Ydegrees</em>
433 control the shears with respect to the , respectively, applied to the text,
434 while <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are offsets that give the location of the text
435 relative to the upper left corner of the image.</p>
437 <p>Using <a href="command-line-options.html#annotate">-annotate</a> <em class="arg">degrees</em>
438 or <a href="command-line-options.html#annotate">-annotate</a> <em class="arg">degrees</em>x<em class="arg">degrees</em> produces an unsheared rotation of the text. The
439 direction of the rotation is positive, which means a clockwise rotation if <em class="arg">degrees</em> is positive. (This conforms to the usual mathematical
440 convention once it is realized that the positive <em>y</em>–direction is
441 conventionally considered to be <em>downward</em> for images.)</p>
443 <p>The new (transformed) coordinates (<em class="arg">x'</em>, <em class="arg">y'</em>) of a pixel at position (<em class="arg">x</em>, <em class="arg">y</em>) in the image are calculated using the following matrix
444 equation.</p> <div class="eqn"><img alt="annotate transformation" src="../images/annotate.png"></img></div>
446 <p>If <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are omitted, they default to 0. This makes the
447 bottom-left of the text becomes the upper-left corner of the image, which is
448 probably undesirable. Adding a <a href="command-line-options.html#gravity">-gravity</a> option in this
449 case leads to nice results.</p>
451 <p>Text is any UTF-8 encoded character sequence. If <em class="arg">text</em>
452 is of the form '@mytext.txt', the text is read from the file
453 <code>mytext.txt</code>. Text in a file is taken literally; no embedded
454 formatting characters are recognized.</p>
456 <div style="margin: auto;">
457 <h4><a id="antialias"></a>-antialias</h4>
460 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Enable/Disable of the rendering of anti-aliasing pixels when
461 drawing fonts and lines.</td><td style="text-align:right;"></td></tr></table>
463 <p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when
464 drawn. Use <a href="command-line-options.html#antialias">+antialias</a> to disable the addition of
465 antialiasing edge pixels. This will then reduce the number of colors added to
466 an image to just the colors being directly drawn. That is, no mixed colors
467 are added when drawing such objects. </p>
469 <div style="margin: auto;">
470 <h4><a id="append"></a>-append</h4>
473 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Join current images vertically or horizontally.</td><td style="text-align:right;"></td></tr></table>
475 <p>This option creates a single longer image image, by joining all the current
476 images in sequence top-to-bottom. Use <a href="command-line-options.html#append">+append</a> to
477 stack images left-to-right. </p>
479 <p>If they are not of the same width, narrower images are padded with the
480 current <a href="command-line-options.html#background">-background</a> color setting, and their
481 position relative to each other can be controlled by the current <a href="command-line-options.html#gravity">-gravity</a> setting. </p>
484 <div style="margin: auto;">
485 <h4><a id="attenuate"></a>-attenuate <em class="arg">value</em></h4>
488 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Lessen (or intensify) when adding noise to an image.</td><td style="text-align:right;"></td></tr></table>
490 <p>If unset the value is equivelent to 1.0, or a maximum noise addition</p>
492 <div style="margin: auto;">
493 <h4><a id="authenticate"></a>-authenticate <em class="arg">password</em></h4>
496 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Decrypt a PDF with a password.</td><td style="text-align:right;"></td></tr></table>
498 <p>Use this option to supply a <em class="arg">password</em> for decrypting
499 a PDF that has been encrypted using Microsoft Crypto API (MSC API). The
500 encrypting using the MSC API is not supported.</p>
502 <p>For a different encryption method, see <a href="command-line-options.html#encipher">-encipher</a>
503 and <a href="command-line-options.html#decipher">-decipher</a>. </p>
507 <div style="margin: auto;">
508 <h4><a id="auto-gamma"></a>-auto-gamma</h4>
511 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Automagically adjust gamma level of image.</td><td style="text-align:right;"></td></tr></table>
513 <p>This calculates the mean values of an image, then applies a calculated <a href="command-line-options.html#gamma">-gamma</a> adjustment so that is the mean color exists in the
514 image it will get a have a value of 50%. </p>
516 <p>This means that any solid 'gray' image becomes 50% gray. </p>
518 <p>This works well for real-life images with little or no extreme dark and
519 light areas, but tend to fail for images with large amounts of bright sky or
520 dark shadows. It also does not work well for diagrams or cartoon like images.
523 <p>It uses the <a href="command-line-options.html#channel">-channel</a> setting, (including the
524 '<em>sync</em>' flag for channel synchronization), to determine which color
525 values is used and modified. As the default <a href="command-line-options.html#channel">-channel</a> setting is '<em>RGB,sync</em>', channels are modified
526 together by the same gamma value, preserving colors. </p>
530 <div style="margin: auto;">
531 <h4><a id="auto-level"></a>-auto-level</h4>
534 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Automagically adjust color levels of image.</td><td style="text-align:right;"></td></tr></table>
536 <p>This is a 'perfect' image normalization operator. It finds the exact
537 minimum and maximum color values in the image and then applies a <a href="command-line-options.html#level">-level</a> operator to stretch the values to the full range of
540 <p>The operator is not typically used for real-life images, image scans, or
541 JPEG format images, as a single 'out-rider' pixel can set a bad min/max values
542 for the <a href="command-line-options.html#level">-level</a> operation. On the other hand it is the
543 right operator to use for color stretching gradient images being used to
544 generate Color lookup tables, distortion maps, or other 'mathematically'
547 <p>The operator is very similar to the <a href="command-line-options.html#normalize">-normalize</a>, <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a>, and <a href="command-line-options.html#linear-stretch">-linear-stretch</a> operators, but without 'histogram binning' or 'clipping'
548 problems that these operators may have. That is <a href="command-line-options.html#auto-level">-auto-level</a> is the perfect or ideal version these operators. </p>
550 <p>It uses the <a href="command-line-options.html#channel">-channel</a> setting, (including the
551 special '<em>sync</em>' flag for channel synchronization), to determine
552 which color values are used and modified. As the default <a href="command-line-options.html#channel">+channel</a> setting is '<em>RGB,sync</em>', the
553 '<em>sync</em>' ensures that the color channels will are modified
554 together by the same gamma value, preserving colors, and ignoring
558 <div style="margin: auto;">
559 <h4><a id="auto-orient"></a>-auto-orient</h4>
562 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">adjusts an image so that its orientation is suitable for viewing (i.e. top-left orientation).</td><td style="text-align:right;"></td></tr></table>
564 <p>This operator reads and resets the EXIF image profile setting 'Orientation'
565 and then performs the appropriate 90 degree rotation on the image to orient
566 the image, for correct viewing. </p>
568 <p>This EXIF profile setting is usually set using a gravity sensor in digital
569 camera, however photos taken directly downward or upward may not have an
570 appropriate value. Also images that have been orientation 'corrected' without
571 reseting this setting, may be 'corrected' again resulting in a incorrect
572 result. If the EXIF profile was previously stripped, the <a href="command-line-options.html#auto-orient">-auto-orient</a> operator will do nothing. </p>
575 <div style="margin: auto;">
576 <h4><a id="average"></a>-average</h4>
579 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Average a set of images.</td><td style="text-align:right;"></td></tr></table>
581 <p>An error results if the images are not identically sized.</p>
584 <div style="margin: auto;">
585 <h4><a id="backdrop"></a>-backdrop</h4>
588 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Display the image centered on a backdrop.</td><td style="text-align:right;">[<a href="animate.html">animate</a>, <a href="display.html">display</a>]</td></tr></table>
590 <p>This backdrop covers the entire workstation screen and is useful for hiding
591 other X window activity while viewing the image. The color of the backdrop is
592 specified as the background color. The color is specified using the format
593 described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
595 <div style="margin: auto;">
596 <h4><a id="background"></a>-background <em class="arg">color</em></h4>
599 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the background color.</td><td style="text-align:right;"></td></tr></table>
601 <p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option. The default background color (if none is
602 specified or found in the image) is white.</p>
604 <div style="margin: auto;">
605 <h4><a id="bench"></a>-bench <em class="arg">iterations</em></h4>
608 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Measure performance.</td><td style="text-align:right;"></td></tr></table>
610 <p>Repeat the entire command for the given number of <em class="arg">iterations</em> and report the user-time and elapsed time. For instance,
611 consider the following command and its output. Modify the benchmark with the
612 -duration to run the benchmark for a fixed number of seconds and -concurrent
613 to run the benchmark in parallel (requires the OpenMP feature).</p>
615 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert logo: -resize 1000% -bench 5 logo.png</span><span class="crtout">Performance[4]: 5i 0.875657ips 6.880u 0:05.710</span></p>
616 <p>In this example, 5 iterations were completed at 0.875657 iterations per
617 second, using 4 threads and 6.88 seconds of the user's allotted time, for
618 a total elapsed time of 5.71 seconds.</p>
620 <div style="margin: auto;">
621 <h4><a id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4>
624 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Add bias when convolving an image.</td><td style="text-align:right;"></td></tr></table>
626 <p>This option shifts the output of <a href="command-line-options.html#convolve">‑convolve</a> so that
627 positive and negative results are relative to the specified bias value. </p>
629 <p>This is important for non-HDRI compilations of ImageMagick when dealing
630 with convolutions that contain negative as well as positive values. This is
631 especially the case with convolutions involving high pass filters or edge
632 detection. Without an output bias, the negative values are clipped at
635 <p>When using an ImageMagick with the HDRI compile-time setting, <a href="command-line-options.html#bias">‑bias</a> is not needed, as ImageMagick is able to store/handle any
636 negative results without clipping to the color value range
637 (0..QuantumRange).</p>
639 <p>See the discussion on HDRI implementations of ImageMagick on the page <a href="high-dynamic-range.html">High Dynamic-Range Images</a>. For more
640 about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this
641 <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
644 <div style="margin: auto;">
645 <h4><a id="black-point-compensation"></a>-black-point-compensation</h4>
648 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Use black point compensation.</td><td style="text-align:right;"></td></tr></table>
650 <div style="margin: auto;">
651 <h4><a id="black-threshold"></a>-black-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
654 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Force to black all pixels below the threshold while leaving all pixels at or above the threshold unchanged.</td><td style="text-align:right;"></td></tr></table>
656 <p> The threshold value can be given as a percentage or as an absolute integer
657 value within [0, <em class="QR">QuantumRange</em>] corresponding to the
658 desired <a href="command-line-options.html#channel">‑channel</a> value. See <a href="command-line-options.html#threshold">‑threshold</a>for more details on thresholds and resulting values. </p>
661 <div style="margin: auto;">
662 <h4><a id="blend"></a>-blend <em class="arg">geometry</em></h4>
665 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">blend an image into another by the given absolute value or percent.</td><td style="text-align:right;">[<a href="composite.html">composite</a>]</td></tr></table>
667 <p>Blend will average the images together ('plus') according to the
668 percentages given and each pixels transparency. If only a single percentage
669 value is given it sets the weight of the composite or 'source' image, while
670 the background image is weighted by the exact opposite amount. That is a
671 <code>-blend 30%</code> merges 30% of the 'source' image with 70% of the
672 'destination' image. Thus it is equivalent to <code>-blend 30x70%</code>.</p>
675 <div style="margin: auto;">
676 <h4><a id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4>
679 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the blue chromaticity primary point.</td><td style="text-align:right;"></td></tr></table>
681 <div style="margin: auto;">
682 <h4><a id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4>
685 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">simulate a scene at nighttime in the moonlight. Start with a factor of 1.5</td><td style="text-align:right;"></td></tr></table>
687 <div style="margin: auto;">
689 <div style="margin: auto;">
690 <h4><a id="blur"></a>-blur <em class="arg">radius</em><br></br>-blur <em class="arg">radius</em>x<em class="arg">sigma</em></h4>
693 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Reduce image noise and reduce detail levels.</td><td style="text-align:right;"></td></tr></table>
695 <p>Convolve the image with a Gaussian or normal distribution using the given
696 <em class="arg">Sigma</em> value. The formula is:</p>
698 <div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"></img>
701 <p>The <em class="arg">Sigma</em> value is the important argument, and
702 determines the actual amount of blurring that will take place. </p>
704 <p>The <em class="arg">Radius</em> is only used to determine the size of the
705 array which will hold the calculated Gaussian distribution. It should be an
706 integer. If not given, or set to zero, IM will calculate the largest possible
707 radius that will provide meaningful results for the Gaussian distribution.
710 <p>The larger the <em class="arg">Radius</em> the slower the
711 operation is. However too small a <em class="arg">Radius</em>, and sever
712 aliasing effects may result. As a guideline, <em class="arg">Radius</em>
713 should be at least twice the <em class="arg">Sigma</em> value, though three
714 times will produce a more accurate result. </p>
716 <p>This option differs from <a href="command-line-options.html#gaussian-blur">-gaussian-blur</a> simply
717 by taking advantage of the separability properties of the distribution. Here
718 we apply a single-dimensional Gaussian matrix in the horizontal direction,
719 then repeat the process in the vertical direction.</p>
721 <p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
722 pixels which are outside the image proper are blurred into the final result.
726 <div style="margin: auto;">
727 <h4>-blur <em class="arg">Width</em>[x<em class="arg">Height</em>[+<em class="arg">Angle</em>]]</h4>
730 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Variably blur and image according to the overlay mapping.</td><td style="text-align:right;">[<a href="composite.html">composite</a>]</td></tr></table>
732 <p>Each pixel in the overlaid region is replaced with an Elliptical Weighted
733 Average (EWA) of the source image, scaled according to the grayscale
736 <p>The ellipse is weighted with sigma set to the given <em class="arg">Width</em> and <em class="arg">Height</em>. The <em class="arg">Height</em>
737 defaults to the <em class="arg">Width</em> for a normal circular Gaussian
738 weighting. The <em class="arg">Angle</em> will rotate the ellipse from
739 horizontal clock-wise. </p>
741 <p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
742 pixels which are outside the image proper are blurred into the final result.
746 <div style="margin: auto;">
747 <h4><a id="border"></a>-border <em class="arg">geometry</em></h4>
750 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Surround the image with a border of color. </td><td style="text-align:right;"></td></tr></table>
752 <p>Set the width and height using the <em class="arg">size</em> portion of the
753 <em class="arg">geometry</em> argument. See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets are
756 <p>As of IM 6.7.8-8, the <em class="arg">geometry</em> arguments behave as follows:</p>
758 <table id="borderTable" class="doc">
759 <col width="20%"></col> <col width="80%"></col>
762 <th style="text-align:center"><em class="arg">size</em></th>
763 <th>General description</th>
768 <td><em class="arg">value</em></td>
769 <td>value is added to both left/right and top/bottom</td>
772 <td><em class="arg">value-x</em>x</td>
773 <td>value-x is added only to left/right and top/bottom are unchanged</td>
776 <td>x<em class="arg">value-y</em></td>
777 <td>value-y is added only to top/bottom and left/right are unchanged</td>
780 <td><em class="arg">value-x</em>x<em class="arg">value-y</em></td>
781 <td>value-x is added to left/right and value-y added to top/bottom</td>
784 <td><em class="arg">value-x</em>x<code>0</code></td>
785 <td>value-x is added only to left/right and top/bottom are unchanged</td>
788 <td><code>0</code>x<em class="arg">value-y</em></td>
789 <td>value-y is added only to top/bottom and left/right are unchanged</td>
796 <td><em class="arg">value</em>%</td>
797 <td>value % of width is added to left/right and value % of height is added to top/bottom</td>
800 <td><em class="arg">value-x</em>x%</td>
801 <td>value-x % of width is added to left/right and to top/bottom</td>
804 <td>x<em class="arg">value-y</em>%</td>
805 <td>value-y % of height is added to top/bottom and to left/right</td>
808 <td><em class="arg">value-x</em>%x<em class="arg">value-y</em>%</td>
809 <td>value-x % of width is added to left/right and value-y % of height is added to top/bottom</td>
812 <td><em class="arg">value-x</em>%x<code>0</code>%</td>
813 <td>value-x % of width is added to left/right and top/bottom are unchanged</td>
816 <td><code>0</code>%x<em class="arg">value-y</em>%</td>
817 <td>value-y % of height is added to top/bottom and left/right are unchanged</td>
823 <p>Set the border color by preceding with the <a href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
825 <p>The <a href="command-line-options.html#border">-border</a> operation is affected by the current <a href="command-line-options.html#compose">-compose</a> setting and assumes that this is using the default
826 '<code>Over</code>' composition method. It generates an image of the appropriate
827 size colors by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> before
828 overlaying the original image in the center of this net image. This means that
829 with the default compose method of '<code>Over</code>' any transparent parts may
830 be replaced by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
831 <p>See also the <a href="command-line-options.html#frame">-frame</a> option, which has more
834 <div style="margin: auto;">
835 <h4><a id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4>
838 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the border color.</td><td style="text-align:right;"></td></tr></table>
840 <p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
842 <p>The default border color is <code>#DFDFDF</code>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p>
844 <div style="margin: auto;">
845 <h4><a id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4>
848 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the border width.</td><td style="text-align:right;">[<a href="animate.html">animate</a>, <a href="display.html">display</a>]</td></tr></table>
850 <div style="margin: auto;">
851 <h4><a id="brightness-contrast"></a>-brightness-contrast <em class="arg">brightness</em><br></br>-brightness-contrast <em class="arg">brightness</em>{x<em class="arg">contrast</em>}{<em class="arg">%</em>}}</h4>
854 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Adjust the brightness and/or contrast of the image.</td><td style="text-align:right;"></td></tr></table>
856 <p>Brightness and Contrast values apply changes to the input image. They are
857 not absolute settings. A brightness or contrast value of zero means no change.
858 The range of values is -100 to +100 on each. Positive values increase the
859 brightness or contrast and negative values decrease the brightness or contrast.
860 To control only contrast, set the brightness=0. To control only brightness,
861 set contrast=0 or just leave it off.</p>
863 <p>You may also use <a href="command-line-options.html#fill">-channel</a> to control which channels to
864 apply the brightness and/or contrast change. The default is to apply the same
865 transformation to all channels.</p>
867 <p>Brightness and Contrast arguments are converted to offset and slope of a
868 linear transform and applied
869 using <a href="command-line-options.html#fill">-function polynomial "slope,offset"</a>.</p>
871 <p>The slope varies from 0 at contrast=-100 to almost vertical at
872 contrast=+100. For brightness=0 and contrast=-100, the result are totally
873 midgray. For brightness=0 and contrast=+100, the result will approach but
874 not quite reach a threshold at midgray; that is the linear transformation
875 is a very steep vertical line at mid gray.</p>
877 <p>Negative slopes, i.e. negating the image, are not possible with this
878 function. All achievable slopes are zero or positive.</p>
880 <p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5
881 at brightness=+100. Thus, when contrast=0 and brightness=100, the result is
882 totally white. Similarly, when contrast=0 and brightness=-100, the result is
885 <p>As the range of values for the arguments are -100 to +100, adding the '%'
886 symbol is no different than leaving it off.</p>
888 <div style="margin: auto;">
889 <h4><a id="cache"></a>-cache <em class="arg">threshold</em></h4>
892 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">(This option has been replaced by the <a href="command-line-options.html#limit">-limit</a> option.)</td><td style="text-align:right;"></td></tr></table>
894 <div style="margin: auto;">
895 <h4><a id="caption"></a>-caption <em class="arg">string</em></h4>
898 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Assign a caption to an image.</td><td style="text-align:right;"></td></tr></table>
900 <p>This option sets the caption meta-data of an image read in after this
901 option has been given. To modify a caption of images already in memory use
902 "<code><a href="command-line-options.html#set">-set</a> caption</code>". </p>
904 <p>The caption can contain special format characters listed in the <a href="escape.html">Format and
905 Print Image Properties</a>. These attributes are expanded when the caption
906 is finally assigned to the individual images. </p>
908 <p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image caption is read from a file titled by the
909 remaining characters in the string. Comments read in from a file are literal;
910 no embedded formatting characters are recognized.</p>
912 <p>Caption meta-data is not visible on the image itself. To do that use the
913 <a href="command-line-options.html#annotate">-annotate</a> or <a href="command-line-options.html#draw">-draw</a> options
919 -caption "%m:%f %wx%h" bird.miff
922 <p>produces an image caption of <code>MIFF:bird.miff 512x480</code> (assuming
923 that the image <code>bird.miff</code> has a width of 512 and a height of
927 <div style="margin: auto;">
928 <h4><a id="cdl"></a>-cdl <em class="arg">filename</em></h4>
931 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">color correct with a color decision list.</td><td style="text-align:right;"></td></tr></table>
933 <p>Here is an example color correction collection:</p>
936 <?xml version="1.0" encoding="UTF-8"?>
937 <ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2">
938 <ColorCorrection id="cc06668">
940 <Slope> 0.9 1.2 0.5 </Slope>
941 <Offset> 0.4 -0.5 0.6 </Offset>
942 <Power> 1.0 0.8 1.5 </Power>
945 <Saturation> 0.85 </Saturation>
947 </ColorCorrection>
948 </ColorCorrectionCollection>
951 <div style="margin: auto;">
952 <h4><a id="channel"></a>-channel <em class="arg">type</em></h4>
955 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Specify those image color channels to which subsequent operators are limited.</td><td style="text-align:right;"></td></tr></table>
957 <p>Choose from: <code>Red</code>, <code>Green</code>, <code>Blue</code>,
958 <code>Alpha</code>, <code>Cyan</code>, <code>Magenta</code>, <code>Yellow</code>,
959 <code>Black</code>, <code>Opacity</code>, <code>Index</code>, <code>RGB</code>,
960 <code>RGBA</code>, <code>CMYK</code>, or <code>CMYKA</code>.</p>
962 <p>The channels above can also be specified as a comma-separated list or can be
963 abbreviated as a concatenation of the letters '<code>R</code>', '<code>G</code>',
964 '<code>B</code>', '<code>A</code>', '<code>O</code>', '<code>C</code>',
965 '<code>M</code>', '<code>Y</code>', '<code>K</code>'.
967 For example, to only select the <code>Red</code> and <code>Blue</code> channels
968 you can either use </p>
972 <p>or you can use the short hand form</p>
977 <p>All the channels that are present in an image can be specified using the
978 special channel type <code>All</code>. Not all operators are 'channel capable',
979 but generally any operators that are generally 'grey-scale' image operators,
980 will understand this setting. See individual operator documentation. </p>
984 <p>On top of the normal channel selection an extra flag can be specified,
985 '<code>Sync</code>'. This is turned on by default and if set means that
986 operators that understand this flag should perform: cross-channel
987 synchronization of the channels. If not specified, then most grey-scale
988 operators will apply their image processing operations to each individual
989 channel (as specified by the rest of the <a href="command-line-options.html#channel">-channel</a>
990 setting) completely independently from each other. </p>
992 <p>For example for operators such as <a href="command-line-options.html#auto-level">-auto-level</a> and
993 <a href="command-line-options.html#auto-gamma">-auto-gamma</a> the color channels are modified
994 together in exactly the same way so that colors will remain in-sync. Without
995 it being set, then each channel is modified separately and
996 independently, which may produce color distortion. </p>
998 <p>The <a href="command-line-options.html#morphology">-morphology</a> '<code>Convolve</code>' method
999 and the <a href="command-line-options.html#compose">-compose</a> mathematical methods, also understands
1000 the '<code>Sync</code>' flag to modify the behaviour of pixel colors according
1001 to the alpha channel (if present). That is to say it will modify the image
1002 processing with the understanding that fully-transparent colors should not
1003 contribute to the final result. </p>
1005 <p>Basically, by default, operators work with color channels in synchronous, and
1006 treats transparency as special, unless the <a href="command-line-options.html#channel">-channel</a>
1007 setting is modified so as to remove the effect of the '<code>Sync</code>' flag.
1008 How each operator does this depends on that operators current implementation.
1009 Not all operators understands this flag at this time, but that is changing.
1012 <p>To print a complete list of channel types, use <a href="command-line-options.html#list">-list
1017 <p>By default, ImageMagick sets <a href="command-line-options.html#channel">-channel</a> to the value
1018 '<code>RGBK,sync</code>', which specifies that operators act on all color
1019 channels except the transparency channel, and that all the color channels are
1020 to be modified in exactly the same way, with an understanding of transparency
1021 (depending on the operation being applied). The 'plus' form <a href="command-line-options.html#channel">+channel</a> will reset the value back to this default. </p>
1023 <p>Options that are affected by the <a href="command-line-options.html#channel">-channel</a> setting
1024 include the following.
1026 <a href="command-line-options.html#auto-gamma">-auto-gamma</a>,
1027 <a href="command-line-options.html#auto-level">-auto-level</a>,
1028 <a href="command-line-options.html#black-threshold">-black-threshold</a>,
1029 <a href="command-line-options.html#blur">-blur</a>,
1030 <a href="command-line-options.html#clamp">-clamp</a>,
1031 <a href="command-line-options.html#clut">-clut</a>,
1032 <a href="command-line-options.html#combine">-combine</a>,
1033 <a href="command-line-options.html#composite">-composite</a> (Mathematical compose methods only),
1034 <a href="command-line-options.html#convolve">-convolve</a>,
1035 <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a>,
1036 <a href="command-line-options.html#evaluate">-evaluate</a>,
1037 <a href="command-line-options.html#function">-function</a>,
1038 <a href="command-line-options.html#fx">-fx</a>,
1039 <a href="command-line-options.html#gaussian-blur">-gaussian-blur</a>,
1040 <a href="command-line-options.html#hald-clut">-hald-clut</a>,
1041 <a href="command-line-options.html#motion-blur">-motion-blur</a>,
1042 <a href="command-line-options.html#morphology">-morphology</a>,
1043 <a href="command-line-options.html#negate">-negate</a>,
1044 <a href="command-line-options.html#normalize">-normalize</a>,
1045 <a href="command-line-options.html#ordered-dither">-ordered-dither</a>,
1046 <a href="command-line-options.html#radial-blur">-radial-blur</a>,
1047 <a href="command-line-options.html#random-threshold">-random-threshold</a>,
1048 <a href="command-line-options.html#separate">-separate</a>,
1049 <a href="command-line-options.html#threshold">-threshold</a>, and
1050 <a href="command-line-options.html#white-threshold">-white-threshold</a>.
1053 <p>Warning, some operators behave differently when the <a href="command-line-options.html#channel">+channel</a> default setting is in effect, verses ANY user defined <a href="command-line-options.html#channel">-channel</a> setting (including the equivalent of the
1054 default). These operators have yet to be made to understand the newer 'Sync'
1057 <p>For example <a href="command-line-options.html#threshold">-threshold</a> will by default gray-scale
1058 the image before thresholding, if no <a href="command-line-options.html#channel">-channel</a> setting
1059 has been defined. This is not 'Sync flag controlled, yet. </p>
1061 <p>Also some operators such as <a href="command-line-options.html#blur">-blur</a>, <a href="command-line-options.html#gaussian-blur">-gaussian-blur</a>, will modify their handling of the
1062 color channels if the '<code>alpha</code>' channel is also enabled by <a href="command-line-options.html#channel">-channel</a>. Generally this done to ensure that
1063 fully-transparent colors are treated as being fully-transparent, and thus any
1064 underlying 'hidden' color has no effect on the final results. Typically
1065 resulting in 'halo' effects. The newer <a href="command-line-options.html#morphology">-morphology</a>
1066 convolution equivalents however does have a understanding of the 'Sync' flag
1067 and will thus handle transparency correctly by default. </p>
1069 <p>As a alpha channel is optional within images, some operators will read the
1070 color channels of an image as a greyscale alpha mask, when the image has no
1071 alpha channel present, and the <a href="command-line-options.html#channel">-channel</a> setting tells
1072 the operator to apply the operation using alpha channels. The <a href="command-line-options.html#clut">-clut</a> operator is a good example of this. </p>
1076 <div style="margin: auto;">
1077 <h4><a id="charcoal"></a>-charcoal <em class="arg">factor</em></h4>
1080 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Simulate a charcoal drawing.</td><td style="text-align:right;"></td></tr></table>
1082 <div style="margin: auto;">
1083 <h4><a id="chop"></a>-chop <em class="arg">geometry</em></h4>
1086 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Remove pixels from the interior of an image.</td><td style="text-align:right;"></td></tr></table>
1088 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <em class="arg">width</em>
1089 and <em class="arg">height</em> given in the of the <em class="arg">size</em>
1090 portion of the <em class="arg">geometry</em> argument give the number of
1091 columns and rows to remove. The <em class="arg">offset</em> portion of
1092 the <em class="arg">geometry</em> argument is influenced by
1093 a <a href="command-line-options.html#gravity">-gravity</a> setting, if present.</p>
1095 <p>The <a href="command-line-options.html#chop">-chop</a> option removes entire rows and columns,
1096 and moves the remaining corner blocks leftward and upward to close the gaps.</p>
1098 <p>While it can remove internal rows and columns of pixels, it is more
1099 typically used with as <a href="command-line-options.html#gravity">-gravity</a> setting and zero
1100 offsets so as to remove a single edge from an image. Compare this to <a href="command-line-options.html#shave">-shave</a> which removes equal numbers of pixels from oppisite
1101 sides of the image. </p>
1103 <p>Using <a href="command-line-options.html#chop">-chop</a> effectively undoes the results of a <a href="command-line-options.html#splice">-splice</a> that was given the same <em class="arg">geometry</em> and <a href="command-line-options.html#gravity">-gravity</a> settings. </p>
1105 <div style="margin: auto;">
1106 <h4><a id="clamp"></a>-clamp</h4>
1109 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">set each pixel whose value is below zero to zero and any the pixel whose value is above the quantum range to the quantum range (e.g. 65535) otherwise the pixel value remains unchanged.</td><td style="text-align:right;"></td></tr></table>
1111 <div style="margin: auto;">
1112 <h4><a id="clip"></a>-clip</h4>
1115 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Apply the clipping path if one is present.</td><td style="text-align:right;"></td></tr></table>
1117 <p>If a clipping path is present, it is applied to subsequent operations.</p>
1119 <p>For example, in the command</p>
1121 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert cockatoo.tif -clip -negate negated.tif</span></p>
1122 <p>only the pixels within the clipping path are negated.</p>
1124 <p>The <a href="command-line-options.html#clip">-clip</a> feature requires SVG support. If the SVG
1125 delegate library is not present, the option is ignored.</p>
1127 <p>Use <a href="command-line-options.html#clip">+clip</a> to disable clipping for subsequent operations.</p>
1129 <div style="margin: auto;">
1130 <h4><a id="clip-mask"></a>-clip-mask</h4>
1133 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Clip the image as defined by this mask.</td><td style="text-align:right;"></td></tr></table>
1135 <p>Use the alpha channel of the current image as a mask. Any areas that is
1136 white is not modified by any of the 'image processing operators' that follow,
1137 until the mask is removed. Pixels in the black areas of the clip mask are
1138 modified per the requirements of the operator. </p>
1140 <p>In some ways this is similar to (though not the same) as defining
1141 a rectangular <a href="command-line-options.html#region">-region</a>, or using the negative of the
1142 mask (third) image in a three image <a href="command-line-options.html#composite">-composite</a>,
1145 <p>Use <a href="command-line-options.html#clip-mask">+clip-mask</a> to disable clipping for subsequent operations.</p>
1147 <div style="margin: auto;">
1148 <h4><a id="clip-path"></a>-clip-path <em class="arg">id</em></h4>
1151 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Clip along a named path from the 8BIM profile.</td><td style="text-align:right;"></td></tr></table>
1153 <p>This is identical to <a href="command-line-options.html#clip">-clip</a> except choose a specific clip path in the event the image has more than one path available. </p>
1155 <p>Use <a href="command-line-options.html#clip-path">+clip-path</a> to disable clipping for subsequent operations.</p>
1157 <div style="margin: auto;">
1158 <h4><a id="clone"></a>-clone <em class="arg">index(s)</em></h4>
1161 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">make a clone of an image (or images).</td><td style="text-align:right;"></td></tr></table>
1163 <p>Inside parenthesis (where the operator is normally used) it will make a
1164 clone of the images from the last 'pushed' image sequence, and adds them to
1165 the end of the current image sequence. Outside parenthesis
1166 (not recommended) it clones the images from the current image sequence. </p>
1168 <p>Specify the image by its index in the sequence. The first image is index
1169 0. Negative indexes are relative to the end of the sequence; for
1170 example, <code>−1</code>
1171 represents the last image of the sequence. Specify a range of images with a
1172 dash (e.g. <code>0−4</code>). Separate multiple indexes with commas but no
1173 spaces (e.g. <code>0,2,5</code>). A value of '<code>0−−1</code> will
1174 effectively clone all the images. </p>
1176 <p>The <a href="command-line-options.html#clone">+clone</a> will simply make a copy of the last image
1177 in the image sequence, and is thus equivalent to using a argument of
1178 '<code>−1</code>'. </p>
1180 <div style="margin: auto;">
1181 <h4><a id="clut"></a>-clut</h4>
1184 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Replace the channel values in the first image using each
1185 corresponding channel in the second image as a <b>c</b>olor
1186 <b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style="text-align:right;"></td></tr></table>
1188 <p>The second (LUT) image is ordinarily a gradient image containing the
1189 histogram mapping of how each channel should be modified. Typically it is a
1190 either a single row or column image of replacement color values. If larger
1191 than a single row or column, values are taken from a diagonal line from
1192 top-left to bottom-right corners.</p>
1194 <p>The lookup is further controlled by the <a href="command-line-options.html#interpolate">-interpolate</a> setting, which is especially handy for an
1195 LUT which is not the full length needed by the ImageMagick installed Quality
1196 (Q) level. Good settings for this are the '<code>bilinear</code>' and
1197 '<code>bicubic</code>' interpolation settings, which give smooth color
1198 gradients, and the '<code>integer</code>' setting for a direct, unsmoothed
1199 lookup of color values. </p>
1201 <p>This operator is especially suited to replacing a grayscale image with a
1202 specific color gradient from the CLUT image. </p>
1204 <p>Only the channel values defined by the <a href="command-line-options.html#channel">-channel</a>
1205 setting will have their values replaced. In particular, since the default <a href="command-line-options.html#channel">-channel</a> setting is <code>RGB</code>, this means that
1206 transparency (alpha/matte channel) is not affected, unless the <a href="command-line-options.html#channel">-channel</a> setting is modified. When the alpha channel is
1207 set, it is treated by the <a href="command-line-options.html#clut">-clut</a> operator in the same way
1208 as the other channels, implying that alpha/matte values are replaced using the
1209 alpha/matte values of the original image. </p>
1211 <p>If either the image being modified, or the lookup image, contains no
1212 transparency (i.e. <a href="command-line-options.html#alpha">-alpha</a> is turned 'off') but the <a href="command-line-options.html#channel">-channel</a> setting includes alpha replacement, then it is
1213 assumed that image represents a gray-scale gradient which is used for the
1214 replacement alpha values. That is you can use a gray-scale CLUT image to
1215 adjust a existing images alpha channel, or you can color a gray-scale image
1216 using colors form CLUT containing the desired colors, including transparency.
1219 <p>See also <a href="command-line-options.html#hald-clut">-hald-clut</a> which replaces colors
1220 according to the lookup of the full color RGB value from a 2D representation
1221 of a 3D color cube. </p>
1224 <div style="margin: auto;">
1225 <h4><a id="coalesce"></a>-coalesce</h4>
1228 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Fully define the look of each frame of an GIF animation sequence, to form a 'film strip' animation.</td><td style="text-align:right;"></td></tr></table>
1230 <p>Overlay each image in an image sequence according to
1231 its <a href="command-line-options.html#dispose">-dispose</a> meta-data, to reproduce the look of
1232 an animation at each point in the animation sequence. All images should be
1233 the same size, and are assigned appropriate GIF disposal settings for the
1234 animation to continue working as expected as a GIF animation. Such frames
1235 are more easily viewed and processed than the highly optimized GIF overlay
1238 <p>The animation can be re-optimized after processing using
1239 the <a href="command-line-options.html#layers">-layers</a> method '<code>optimize</code>', although
1240 there is no guarantee that the restored GIF animation optimization is
1241 better than the original. </p>
1244 <div style="margin: auto;">
1245 <h4><a id="colorize"></a>-colorize <em class="arg">value</em></h4>
1248 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Colorize the image by an amount specified by <em class="arg">value</em> using the color specified by the most recent <a href="command-line-options.html#fill">-fill</a> setting.</td><td style="text-align:right;"></td></tr></table>
1250 <p>Specify the amount of colorization as a percentage. Separate colorization
1251 values can be applied to the red, green, and blue channels of the image with
1252 a comma-delimited list of colorization
1253 values (e.g., <code>-colorize 0,0,50</code>).</p>
1255 <div style="margin: auto;">
1256 <h4><a id="colormap"></a>-colormap <em class="arg">type</em></h4>
1259 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Define the colormap type.</td><td style="text-align:right;">[<a href="animate.html">animate</a>, <a href="display.html">display</a>]</td></tr></table>
1261 <p>The <em class="arg">type</em> can be <code>shared</code> or <code>private</code>.</p>
1263 <p>This option only applies when the default X server visual
1264 is <code>PseudoColor</code> or <code>GrayScale</code>. Refer
1265 to <a href="command-line-options.html#visual">-visual</a> for more details. By default,
1266 a shared colormap is allocated. The image shares colors with
1267 other X clients. Some image colors could be approximated,
1268 therefore your image may look very different than intended.
1269 If <code>private</code> is chosen, the image colors appear exactly
1270 as they are defined. However, other clients may go <em>technicolor</em>
1271 when the image colormap is installed.</p>
1273 <div style="margin: auto;">
1274 <h4><a id="colors"></a>-colors <em class="arg">value</em></h4>
1277 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the preferred number of colors in the image.</td><td style="text-align:right;"></td></tr></table>
1279 <p>The actual number of colors in the image may be less than your request,
1280 but never more. Note that this a color reduction option. Images with fewer
1281 unique colors than specified by <em class="arg">value</em> will have any
1282 duplicate or unused colors removed. The ordering of an existing color
1283 palette may be altered. When converting an image from color to grayscale,
1284 it is more efficient to convert the image to the gray colorspace before
1285 reducing the number of colors. Refer to
1286 the <a href="quantize.html">
1287 color reduction algorithm</a> for more details.</p>
1289 <div style="margin: auto;">
1290 <h4><a id="color-matrix"></a>-color-matrix <em class="arg">matrix</em></h4>
1293 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">apply color correction to the image.</td><td style="text-align:right;"></td></tr></table>
1295 <p>This option permits saturation changes, hue rotation, luminance to alpha,
1296 and various other effects. Although variable-sized transformation matrices
1297 can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6
1298 for CMYKA (or RGBA with offsets). The matrix is similar to those used by
1299 Adobe Flash except offsets are in column 6 rather than 5 (in support of
1300 CMYKA images) and offsets are normalized (divide Flash offset by 255).</p>
1302 <p>As an example, to add contrast to an image with offsets, try this command:</p>
1305 convert kittens.jpg -color-matrix \
1306 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \
1307 0.0 1.5 0.0 0.0, 0.0, -0.157 \
1308 0.0 0.0 1.5 0.0, 0.0, -0.157 \
1309 0.0 0.0 0.0 1.0, 0.0, 0.0 \
1310 0.0 0.0 0.0 0.0, 1.0, 0.0 \
1311 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png
1313 <div style="margin: auto;">
1314 <h4><a id="colorspace"></a>-colorspace <em class="arg">value</em></h4>
1317 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the image colorspace.</td><td style="text-align:right;"></td></tr></table>
1326 OHTA Rec601YCbCr Rec709YCbCr RGB
1327 scRGB sRGB Transparent XYZ
1332 <p>To print a complete list of colorspaces, use <a href="command-line-options.html#list">-list colorspace</a>.</p>
1334 <p>For a more accurate color conversion to or from the linear RGB, CMYK, or grayscale colorspaces, use the <a href="command-line-options.html#profile">-profile</a> option. Note, ImageMagick assumes the sRGB colorspace if the image format does not indicate otherwise. For colorspace conversion, the gamma function is first removed to produce linear RGB.</p>
1337 <caption>Conversion of RGB to Other Color Spaces</caption>
1338 <tr><th align="left" valign="middle">CMY</th></tr>
1339 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr>
1340 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr>
1341 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr>
1342 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr>
1343 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr>
1344 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr>
1345 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr>
1346 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr>
1348 <tr><th align="left" valign="middle">Gray</th></tr>
1349 <tr><td align="left" valign="middle">Gray = 0.298839*R+0.586811*G+0.114350*B</td></tr>
1351 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr>
1352 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1353 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
1354 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr>
1356 <tr><th align="left" valign="middle">HSL — Hue, Saturation, Lightness; like a double cone end-to-end with peaks at very top and bottom</th></tr>
1357 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1358 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
1359 <tr><td align="left" valign="middle">L=distance along axis from bottom upward; L=0.5*max(R,G,B) + 0.5*min(R,G,B); <em>intensity-like</em></td></tr>
1361 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr>
1362 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr>
1363 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr>
1364 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr>
1366 <tr><th align="left" valign="middle">LAB</th></tr>
1367 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
1368 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
1369 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
1371 <tr><th align="left" valign="middle">LOG</th></tr>
1372 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
1373 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
1374 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
1376 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr>
1377 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr>
1378 <tr><td align="left" valign="middle">I2=(0.50000*R+0.00000*G−0.50000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1379 <tr><td align="left" valign="middle">I3=(−0.25000*R+0.50000*G−0.25000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1381 <tr><th align="left" valign="middle">Rec601Luma</th></tr>
1382 <tr><td align="left" valign="middle">Gray = 0.298839*R+0.586811*G+0.114350*B</td></tr>
1384 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr>
1385 <tr><td align="left" valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <em>intensity-like</em></td></tr>
1386 <tr><td align="left" valign="middle">Cb=(−0.168736*R-0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1387 <tr><td align="left" valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1389 <tr><th align="left" valign="middle">Rec709Luma</th></tr>
1390 <tr><td align="left" valign="middle">Gray=0.212656*R+0.715158*G+0.072186*B</td></tr>
1392 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr>
1393 <tr><td align="left" valign="middle">Y=0.212656*R+0.715158*G+0.072186*B; <em>intensity-like</em></td></tr>
1394 <tr><td align="left" valign="middle">Cb=(−0.114572*R−0.385428*G+0.500000*B)+(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1395 <tr><td align="left" valign="middle">Cr=(0.500000*R−0.454153*G−0.045847*B)+(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1397 <tr><th align="left" valign="middle">sRGB</th></tr>
1398 <tr><td align="left" valign="middle">if R ≤ .0.0031308 then Rs=R/12.92 else Rs=1.055 R ^ (1.0 / 2.4) ? 0.055</td></tr>
1399 <tr><td align="left" valign="middle">if G ≤ .0.0031308 then Gs=B/12.92 else Gs=1.055 R ^ (1.0 / 2.4) ? 0.055</td></tr>
1400 <tr><td align="left" valign="middle">if B ≤ .0.0031308 then Bs=B/12.92 else Bs=1.055 R ^ (1.0 / 2.4) ? 0.055</td></tr>
1402 <tr><th align="left" valign="middle">XYZ</th></tr>
1403 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr>
1404 <tr><td align="left" valign="middle">Y=0.212656*R+0.715158*G+0.0721856*B</td></tr>
1405 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr>
1407 <tr><th align="left" valign="middle">YCC</th></tr>
1408 <tr><td align="left" valign="middle">Y=(0.298839*R+0.586811*G+0.114350*B) (with complicated scaling); <em>intensity-like</em></td></tr>
1409 <tr><td align="left" valign="middle">C1=(−0.298839*R−0.586811*G+0.88600*B) (with complicated scaling)</td></tr>
1410 <tr><td align="left" valign="middle">C2=(0.70100*R−0.586811*G−0.114350*B) (with complicated scaling)</td></tr>
1412 <tr><th align="left" valign="middle">YCbCr</th></tr>
1413 <tr><td align="left" valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <em>intensity-like</em></td></tr>
1414 <tr><td align="left" valign="middle">Cb=(−0.168736*R−0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1415 <tr><td align="left" valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1417 <tr><th align="left" valign="middle">YIQ</th></tr>
1418 <tr><td align="left" valign="middle">Y=0.298839*R+0.586811*G+0.114350*B; <em>intensity-like</em></td></tr>
1419 <tr><td align="left" valign="middle">I=(0.59600*R−0.27400*G−0.32200*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1420 <tr><td align="left" valign="middle">Q=(0.21100*R−0.52300*G+0.31200*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1422 <tr><th align="left" valign="middle">YPbPr</th></tr>
1423 <tr><td align="left" valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <em>intensity-like</em></td></tr>
1424 <tr><td align="left" valign="middle">Pb=(−0.168736*R−0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1425 <tr><td align="left" valign="middle">Pr=(0.500000*R−0.418688*G−0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1427 <tr><th align="left" valign="middle">YUV</th></tr>
1428 <tr><td align="left" valign="middle">Y=0.298839*R+0.586811*G+0.114350*B; <em>intensity-like</em></td></tr>
1429 <tr><td align="left" valign="middle">U=(−0.14740*R−0.28950*G+0.43690*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1430 <tr><td align="left" valign="middle">V=(0.61500*R−0.51500*G−0.10000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
1433 <p>Note the scRGB colorspace requires HDRI support otherwise it behaves just like linear RGB.</p>
1435 <div style="margin: auto;">
1436 <h4><a id="combine"></a>-combine</h4>
1439 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Combine one or more images into a single image.</td><td style="text-align:right;"></td></tr></table>
1441 <p>The channels (previously set by <a href="command-line-options.html#channel">-channel</a>) of the
1442 combined image are taken from the grayscale values of each image in the
1443 sequence, in order. For the default -channel setting of <code>RGB</code>, this
1444 means the first image is assigned to the <code>Red</code> channel, the second
1445 to the <code>Green</code> channel, the third to the <code>Blue</code>.</p>
1447 <p>This option can be thought of as the inverse to <a href="command-line-options.html#separate">-separate</a>, so long as the channel settings are the same.
1448 Thus, in the following example, the final image should be a copy of the
1451 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert original.png -channel RGB -separate sepimage.png</span><span class="crtout"></span><span class="crtprompt"> $ </span><span class="crtin">convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB \ <br></br> -combine imagecopy.png</span></p>
1452 <div style="margin: auto;">
1453 <h4><a id="comment"></a>-comment <em class="arg">string</em></h4>
1456 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Embed a comment in an image.</td><td style="text-align:right;"></td></tr></table>
1458 <p>This option sets the comment meta-data of an image read in after this
1459 option has been given. To modify a comment of images already in memory use
1460 "<code><a href="command-line-options.html#set">-set</a> comment</code>". </p>
1462 <p>The comment can contain special format characters listed in the <a href="escape.html">Format and
1463 Print Image Properties</a>. These attributes are expanded when the comment
1464 is finally assigned to the individual images. </p>
1466 <p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image comment is read from a file titled by the
1467 remaining characters in the string. Comments read in from a file are literal;
1468 no embedded formatting characters are recognized.</p>
1470 <p>Comment meta-data are not visible on the image itself. To do that use the
1471 <a href="command-line-options.html#annotate">-annotate</a> or <a href="command-line-options.html#draw">-draw</a> options
1477 -comment "%m:%f %wx%h" bird.miff
1480 <p>produces an image comment of <code>MIFF:bird.miff 512x480</code> (assuming
1481 that the image <code>bird.miff</code> has a width of 512 and a height of
1484 <div style="margin: auto;">
1485 <h4><a id="compose"></a>-compose <em class="arg">operator</em></h4>
1488 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the type of image composition.</td><td style="text-align:right;"></td></tr></table>
1490 <p>See <a href="compose.html">Alpha Compositing</a> for
1491 a detailed discussion of alpha compositing.</p>
1493 <p>This setting effects image processing operators that merge two (or more)
1494 images together in some way. This includes the operators,
1495 <a href="command-line-options.html#composite">-composite</a>,
1496 <a href="command-line-options.html#layers">-layers</a> composite,
1497 <a href="command-line-options.html#flatten">-flatten</a>,
1498 <a href="command-line-options.html#mosaic">-mosaic</a>,
1499 <a href="command-line-options.html#layers">-layers</a> merge,
1500 <a href="command-line-options.html#border">-border</a>,
1501 <a href="command-line-options.html#frame">-frame</a>,
1502 and <a href="command-line-options.html#extent">-extent</a>. </p>
1504 <p>It is also one of the primary options for the "<code>composite</code>"
1508 <div style="margin: auto;">
1509 <h4><a id="composite"></a>-composite</h4>
1512 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Perform alpha composition on two images and an optional mask</td><td style="text-align:right;"></td></tr></table>
1514 <p>Take the first image 'destination' and overlay the second 'source' image
1515 according to the current <a href="command-line-options.html#compose">-compose</a> setting. The location
1516 of the 'source' or 'overlay' image is controlled according to <a href="command-line-options.html#geometry">-geometry</a>, and <a href="command-line-options.html#geometry">-geometry</a>
1519 <p>If a third image is given this is treated as a gray-scale 'mask' image
1520 relative to the first 'destination' image. This mask will limit what parts of
1521 the destination can be modified by the image composition. However for the
1522 '<code>displace</code>' compose method, the mask is used to provide a separate
1523 Y-displacement image instead. </p>
1525 <p>If a <a href="command-line-options.html#compose">-compose</a> method requires extra numerical
1526 arguments or flags these can be provided by setting the <a href="command-line-options.html#set">-set</a> '<code class="arg">option:compose:args</code>'
1527 appropriately for the compose method. </p>
1529 <p>Some <a href="command-line-options.html#compose">-compose</a> methods can modify the 'destination'
1530 image outside the overlay area. You can disable this by setting the special <a href="command-line-options.html#set">-set</a> '<code class="arg">option:compose:outside-overlay</code>'
1531 to '<code>false</code>'. </p>
1534 <div style="margin: auto;">
1535 <h4><a id="compress"></a>-compress <em class="arg">type</em></h4>
1538 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Use pixel compression specified by <em class="arg">type</em> when writing the image.</td><td style="text-align:right;"></td></tr></table>
1540 <p>Choices are: <code class="arg">None</code>, <code class="arg">BZip</code>, <code class="arg">Fax</code>, <code class="arg">Group4</code>, <code class="arg">JPEG</code>, <code class="arg">JPEG2000</code>, <code class="arg">Lossless</code>, <code class="arg">LZW</code>, <code class="arg">RLE</code> or <code class="arg">Zip</code>.</p>
1542 <p>To print a complete list of compression types, use <a href="command-line-options.html#list">-list
1545 <p>Specify <a href="command-line-options.html#compress">+compress</a> to store the binary image in an
1546 uncompressed format. The default is the compression type of the specified
1549 <p>If <code>LZW</code> compression is specified but LZW compression has not been
1550 enabled, the image data is written in an uncompressed LZW format that can be
1551 read by LZW decoders. This may result in larger-than-expected GIF files.</p>
1553 <p><code>Lossless</code> refers to lossless JPEG, which is only available if the
1554 JPEG library has been patched to support it. Use of lossless JPEG is generally
1555 not recommended.</p>
1558 When writing an ICO file, you may request that the images be encoded in
1559 PNG format, by specifying <code>Zip</code> compression.</p>
1562 When writing a JNG file, specify <code>Zip</code> compression to request that
1563 the alpha channel be encoded in PNG "IDAT" format, or <code>JPEG</code>
1564 to request that it be encoded in JPG "JDAA" format.</p>
1566 <p>Use the <a href="command-line-options.html#quality">-quality</a> option to set the compression level
1567 to be used by JPEG, PNG, MIFF, and MPEG encoders.
1568 Use the <a href="command-line-options.html#sampling-factor">-sampling-factor</a> option to set the
1569 sampling factor to be used by JPEG, MPEG, and YUV encoders for down-sampling
1570 the chroma channels.</p>
1572 <div style="margin: auto;">
1573 <h4><a id="contrast"></a>-contrast</h4>
1576 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Enhance or reduce the image contrast.</td><td style="text-align:right;"></td></tr></table>
1578 <p>This option enhances the intensity differences between the lighter and
1579 darker elements of the image. Use <a href="command-line-options.html#contrast">-contrast</a> to enhance
1580 the image or <a href="command-line-options.html#contrast">+contrast</a> to reduce the image
1583 <p>For a more pronounced effect you can repeat the option:</p>
1585 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert rose: -contrast -contrast rose_c2.png</span></p>
1586 <div style="margin: auto;">
1587 <h4><a id="contrast-stretch"></a>-contrast-stretch <em class="arg">black-point</em><br></br>-contrast-stretch <em class="arg">black-point</em>{x<em class="arg">white-point</em>}{<em class="arg">%</em>}}</h4>
1590 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Increase the contrast in an image by <em>stretching</em> the range of intensity values.</td><td style="text-align:right;"></td></tr></table>
1592 <p>While performing the stretch, black-out at most <em class="arg">black-point</em> pixels and white-out at most <em class="arg">white-point</em> pixels. Or, if percent is used, black-out at most
1593 <em class="arg">black-point %</em> pixels and white-out at most <em class="arg">white-point %</em> pixels.</p>
1595 <p>Prior to ImageMagick 6.4.7-0, <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a> will black-out at most <em class="arg">black-point</em> pixels and white-out at most <em class="arg">total pixels
1596 minus white-point</em> pixels. Or, if percent is used, black-out at most <em class="arg">black-point %</em> pixels and white-out at most <em class="arg">100% minus white-point %</em> pixels.</p>
1598 <p>Note that <code>-contrast-stretch 0</code> will modify the image such that
1599 the image's min and max values are stretched to 0 and <em class="QR">QuantumRange</em>, respectively, without any loss of data due to burn-out or
1600 clipping at either end. This is not the same as <a href="command-line-options.html#normalize">-normalize</a>, which is equivalent to <code>-contrast-stretch 0.15x0.05%</code> (or
1601 prior to ImageMagick 6.4.7-0, <code>-contrast-stretch 2%x99%</code>).</p>
1603 <p>Internally operator works by creating a histogram bin, and then uses that
1604 bin to modify the image. As such some colors may be merged together when they
1605 originally fell into the same 'bin'. </p>
1607 <p>All the channels are normalized in concert by the came amount so as to
1608 preserve color integrity, when the default <a href="command-line-options.html#channel">+channel</a>
1609 setting is in use. Specifying any other <a href="command-line-options.html#channel">-channel</a>
1610 setting will normalize the RGB channels independently.</p>
1612 <p>See also <a href="command-line-options.html#auto-level">-auto-level</a> for a 'perfect'
1613 normalization of mathematical images. </p>
1615 <p>This operator is under review for re-development. </p>
1618 <div style="margin: auto;">
1619 <h4><a id="convolve"></a>-convolve <em class="arg">kernel</em></h4>
1622 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Convolve an image with a user-supplied convolution kernel.</td><td style="text-align:right;"></td></tr></table>
1624 <p>The <em class="arg">kernel</em> is a matrix specified as
1625 a comma-separated list of integers (with no spaces), ordered left-to right,
1626 starting with the top row. Presently, only odd-dimensioned kernels are
1627 supported, and therefore the number of entries in the specified <em class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25,
1628 7<sup>2</sup>=49, etc. </p>
1630 <p>Note that the <a href="command-line-options.html#convolve">‑convolve</a> operator supports the <a href="command-line-options.html#bias">‑bias</a> setting. This option shifts the convolution so that
1631 positive and negative results are relative to a user-specified bias value.
1632 This is important for non-HDRI compilations of ImageMagick when dealing with
1633 convolutions that contain negative as well as positive values. This is
1634 especially the case with convolutions involving high pass filters or edge
1635 detection. Without an output bias, the negative values is clipped at zero.
1638 <p>When using an ImageMagick with the HDRI compile-time setting, <a href="command-line-options.html#bias">‑bias</a> is not needed, as ImageMagick is able to store/handle any
1639 negative results without clipping to the color value range (0..QuantumRange).
1640 See the discussion on HDRI implementations of ImageMagick on the page <a href="high-dynamic-range.html">High
1641 Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this
1642 <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
1646 <div style="margin: auto;">
1647 <h4><a id="crop"></a>-crop <em class="arg">geometry</em>{<em class="arg">@</em>}{<em class="arg">!</em>}</h4>
1650 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Cut out one or more rectangular regions of the image.</td><td style="text-align:right;"></td></tr></table>
1652 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
1654 <p>The <em class="arg">width</em> and <em class="arg">height</em> of the <em class="arg">geometry</em> argument give the size of the image that remains
1655 after cropping, and <em class="arg">x</em> and <em class="arg">y</em> in the
1656 <em class="arg">offset</em> (if present) gives the location of the top left
1657 corner of the cropped image with respect to the original image. To specify the
1658 amount to be removed, use <a href="command-line-options.html#shave">-shave</a> instead.</p>
1660 <p>If the <em class="arg">x</em> and <em class="arg">y</em> offsets are
1661 present, a single image is generated, consisting of the pixels from the
1662 cropping region. The offsets specify the location of the upper left corner of
1663 the cropping region measured downward and rightward with respect to the upper
1664 left corner of the image. If the <a href="command-line-options.html#gravity">-gravity</a> option is
1665 present with <code>NorthEast</code>, <code>East</code>, or <code>SouthEast</code>
1666 gravity, it gives the distance leftward from the right edge of the image to
1667 the right edge of the cropping region. Similarly, if the <a href="command-line-options.html#gravity">-gravity</a> option is present with <code>SouthWest</code>,
1668 <code>South</code>, or <code>SouthEast</code> gravity, the distance is measured
1669 upward between the bottom edges.</p>
1671 <p>If the <em class="arg">x</em> and <em class="arg">y</em> offsets are
1672 omitted, a set of tiles of the specified geometry, covering the entire input
1673 image, is generated. The rightmost tiles and the bottom tiles are smaller if
1674 the specified geometry extends beyond the dimensions of the input image.</p>
1676 <p>You can add the <em class="arg">@</em> to the geometry argument to equally divide the image into the number of tiles generated.</p>
1678 <p>By adding a exclamation character flag to the geometry argument, the
1679 cropped images virtual canvas page size and offset is set as if the
1680 geometry argument was a viewport or window. This means the canvas page size
1681 is set to exactly the same size you specified, the image offset set
1682 relative top left corner of the region cropped. </p>
1684 <p>If the cropped image 'missed' the actual image on its virtual canvas, a
1685 special single pixel transparent 'missed' image is returned, and a 'crop
1686 missed' warning given. </p>
1688 <p>It might be necessary to <a href="command-line-options.html#repage">+repage</a> the image prior to
1689 cropping the image to ensure the crop coordinate frame is relocated to the
1690 upper-left corner of the visible image.
1692 Similarly you may want to use <a href="command-line-options.html#repage">+repage</a> after cropping to
1693 remove the page offset that will be left behind. This is especially true when
1694 you are going to write to an image format such as PNG that supports an image
1697 <div style="margin: auto;">
1698 <h4><a id="cycle"></a>-cycle <em class="arg">amount</em></h4>
1701 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">displace image colormap by amount.</td><td style="text-align:right;"></td></tr></table>
1703 <p><em class="arg">Amount</em> defines the number of positions each
1704 colormap entry is shifted.</p>
1707 <div style="margin: auto;">
1708 <h4><a id="debug"></a>-debug <em class="arg">events</em></h4>
1711 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">enable debug printout.</td><td style="text-align:right;"></td></tr></table>
1713 <p>The <code>events</code> parameter specifies which events are to be logged. It
1714 can be either <code>None</code>, <code>All</code>, <code>Trace</code>, or
1715 a comma-separated list consisting of one or more of the following domains:
1716 <code>Accelerate</code>, <code>Annotate</code>, <code>Blob</code>, <code>Cache</code>,
1717 <code>Coder</code>, <code>Configure</code>, <code>Deprecate</code>,
1718 <code>Exception</code>, <code>Locale</code>, <code>Render</code>,
1719 <code>Resource</code>, <code>Security</code>, <code>TemporaryFile</code>,
1720 <code>Transform</code>, <code>X11</code>, or <code>User</code>. </p>
1723 <p>For example, to log cache and blob events, use.</p>
1725 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert -debug "Cache,Blob" rose: rose.png</span></p>
1726 <p>The <code>User</code> domain is normally empty, but developers can log user
1727 events in their private copy of ImageMagick.</p>
1729 <p>To print the complete list of debug methods, use <a href="command-line-options.html#list">-list
1732 <p>Use the <a href="command-line-options.html#log">-log</a> option to specify the format for debugging
1735 <p>Use <a href="command-line-options.html#debug">+debug</a> to turn off all logging.</p>
1737 <p>Debugging may also be set using the <code>MAGICK_DEBUG</code> <a href="resources.html#environment">environment variable</a>. The allowed values for the <code>MAGICK_DEBUG</code>
1738 environment variable are the same as for the <a href="command-line-options.html#debug">-debug</a>
1742 <div style="margin: auto;">
1743 <h4><a id="decipher"></a>-decipher <em class="arg">filename</em></h4>
1746 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Decipher and restore pixels that were previously transformed by
1747 <a href="command-line-options.html#encipher">-encipher</a>.</td><td style="text-align:right;"></td></tr></table>
1749 <p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
1751 <p>For more information, see the webpage, <a href="../www/cipher.html">ImageMagick: Encipher or
1752 Decipher an Image</a>.</p>
1755 <div style="margin: auto;">
1756 <h4><a id="deconstruct"></a>-deconstruct</h4>
1759 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">find areas that has changed between images </td><td style="text-align:right;"></td></tr></table>
1761 <p>Given a sequence of images all the same size, such as produced by <a href="command-line-options.html#coalesce">-coalesce</a>, replace the second and later images, with
1762 a smaller image of just the area that changed relative to the previous image.
1765 <p>The resulting sequence of images can be used to optimize an animation
1766 sequence, though will not work correctly for GIF animations when parts of the
1767 animation can go from opaque to transparent. </p>
1769 <p>This option is actually equivalent to the <a href="command-line-options.html#layers">-layers</a>
1770 method '<code>compare-any</code>'. </p>
1773 <div style="margin: auto;">
1774 <h4><a id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4>
1777 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">add specific global settings generally used to control
1778 coders and image processing operations.</td><td style="text-align:right;"></td></tr></table>
1780 <p>This option creates one or more definitions for coders and decoders to use
1781 while reading and writing image data. Definitions are generally used to
1782 control image file format coder modules, and image processing operations,
1783 beyond what is provided by normal means. Defined settings are listed in <a href="command-line-options.html#verbose">-verbose</a> information ("<code>info:</code>" output format)
1784 as "Artifacts". </p>
1786 <p>If <em class="arg">value</em> is missing for a definition, an empty-valued
1787 definition of a flag is created with that name. This used to control on/off
1788 options. Use <a href="command-line-options.html#define">+define key</a> to remove definitions
1789 previously created. Use <a href="command-line-options.html#define">+define "*"</a> to remove all
1790 existing definitions.</p>
1792 <p>The same 'artifact' settings can also be defined using the <a href="command-line-options.html#set">-set "option:<em class="arg">key</em>" "<em class="arg">value</em>"</a> option, which also allows the use of <a href="escape.html">Format and Print Image
1793 Properties</a> in the defined value. </p>
1795 <p>The <em>option</em> and <em>key</em> are case-independent (they are
1796 converted to lowercase for use within the decoders) while the <em>value</em>
1797 is case-dependent.</p>
1799 <p>Such settings are global in scope, and affect all images and operations. </p>
1801 <p>The following definitions are just some of the artifacts that are
1806 <dt>compose:args=<em class="arg">arguments</em></dt>
1807 <dd>Sets certain compose argument values when using convert ... -compose ...
1808 -composite. See <a href="compose.html">Image Composition</a></dd>
1810 <dt>distort:scale=<em class="arg">value</em></dt>
1811 <dd>Sets the output scaling factor for use with <a href="command-line-options.html#distort">-distort</a></dd>
1813 <dt>distort:viewport=WxH+X+Y</dt>
1814 <dd>Sets the viewport for use with <a href="command-line-options.html#distort">-distort</a></dd>
1816 <dt>dcm:display-range=reset</dt>
1817 <dd>Set the display range to the minimum and maximum pixel values for the
1818 DCM image format.</dd>
1820 <dt>dot:layout-engine=<em class="arg">value</em></dt>
1821 <dd>Set the specify the layout engine for the DOT image format (e.g.
1822 <code>neato</code>).</dd>
1824 <dt>jpeg:colors=<em class="arg">value</em></dt>
1825 <dd>Set the desired number of colors and let the JPEG encoder do the
1828 <dt>jpeg:block-smoothing=<em class="arg">on|off</em></dt>
1830 <dt>jpeg:dct-method=<em class="arg">value</em></dt>
1831 <dd>Choose from <code>default</code>, <code>fastest</code>, <code>float</code>,
1832 <code>ifast</code>, and <code>islow</code>.</dd>
1834 <dt>jpeg:extent=<em class="arg">value</em></dt>
1835 <dd>Restrict the maximum JPEG file size, for example <code>-define
1836 jpeg:extent=400kb</code>. The JPEG encoder will search for the highest
1837 compression quality level that results in an output file that does not
1838 exceed the value. The <code>-quality</code> option is ignored if it
1839 is also present.</dd>
1841 <dt>jpeg:fancy-upsampling=<em class="arg">on|off</em></dt>
1843 <dt>jpeg:optimize-coding=<em class="arg">on|off</em></dt>
1845 <dt>jpeg:q-table=<em class="arg">table</em></dt>
1847 <dt>jpeg:sampling-factor=<em class="arg">sampling-factor-string</em></dt>
1849 <dt>jpeg:size=<em class="arg">geometry</em></dt>
1850 <dd>Set the size hint of a JPEG image, for
1851 example, <code>-define jpeg:size=128x128</code>.
1852 It is most useful for increasing performance and reducing the memory
1853 requirements when reducing the size of a large JPEG image.</dd>
1855 <dt>jp2:rate=<em class="arg">value</em></dt>
1856 <dd>Specify the compression factor to use while writing JPEG-2000 files. The
1857 compression factor is the reciprocal of the compression ratio. The valid
1858 range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined,
1859 this value overrides the -quality setting. A quality setting of 75
1860 results in a rate value of 0.06641.</dd>
1862 <dt>mng:need-cacheoff</dt>
1863 <dd>turn playback caching off for streaming MNG.</dd>
1865 <dt>png:bit-depth=<em class="arg">value</em></dt>
1866 <dt>png:color-type=<em class="arg">value</em></dt>
1867 <dd>desired bit-depth and color-type for PNG output. You can force the PNG
1868 encoder to use a different bit-depth and color-type than it would have
1869 normally selected, but only if this does not cause any loss of image
1870 quality. Any attempt to reduce image quality is treated as an error and no
1871 PNG file is written. E.g., if you have a 1-bit black-and-white image, you
1872 can use these "defines" to cause it to be written as an 8-bit grayscale,
1873 indexed, or even a 64-bit RGBA. But if you have a 16-million color image,
1874 you cannot force it to be written as a grayscale or indexed PNG. If you
1875 wish to do this, you must use the appropriate <a href="command-line-options.html#depth">-depth</a>,
1876 <a href="command-line-options.html#colors">-colors</a>, or <a href="command-line-options.html#type">-type</a> directives to
1877 reduce the image quality prior to using the PNG encoder. Note that in
1878 indexed PNG files, "bit-depth" refers to the number of bits per index,
1879 which can be 1, 2, 4, or 8. In such files, the color samples always have
1882 <dt>png:compression-filter=<em class="arg">value</em></dt>
1883 <dd> valid values are 0 through 7. 0-4 are the corresponding PNG filters,
1884 5 means adaptive filtering except for images with a colormap, 6 means
1885 adaptive filtering for all images, 7 means MNG "loco" compression.</dd>
1887 <dt>png:compression-level=<em class="arg">value</em></dt>
1888 <dd> valid values are 0 through 9, with 0 providing the least but fastest
1889 compression and 9 usually providing the best and always the slowest.</dd>
1891 <dt>png:compression-strategy=<em class="arg">value</em></dt>
1892 <dd> valid values are 0 through 4, meaning default, filtered, huffman_only,
1893 rle, and fixed ZLIB compression strategy. If you are using an old zlib
1894 that does not support Z_RLE (before 1.2.0) or Z_FIXED (before 1.2.2.2),
1895 values 3 and 4, respectively, will use the zlib default strategy
1898 <dt>png:format=<em class="arg">value</em></dt>
1899 <dd> valid values are <em class="arg">png8</em>, <em class="arg">png24</em>,
1900 <em class="arg">png32</em>, <em class="arg">png48</em>,
1901 <em class="arg">png64</em>, and <em class="arg">png00</em>.
1902 This property can be useful for specifying
1903 the specific PNG format to be used, when the usual method of prepending the
1904 format name to the output filename is inconvenient, such as when writing
1905 a PNG-encoded ICO file.
1906 Value = <em class="arg">png8</em> reduces the number of colors to 256,
1907 only one of which may be fully transparent, if necessary. The other
1908 values do not force any reduction of quality; it is an error to request
1909 a format that cannot represent the image data without loss (except that
1910 it is allowed to reduce the bit-depth from 16 to 8 for all formats).
1911 Value = <em class="arg">png24</em> and <em class="arg">png48</em>
1912 allow transparency, only if a single color is fully transparent and that
1913 color does not also appear in an opaque pixel; such transparency is
1914 written in a PNG <code>tRNS</code> chunk.
1915 Value = <em class="arg">png00</em> causes the image to inherit its
1916 color-type and bit-depth from the input image, if the input was also
1919 <dt>png:exclude-chunk=<em class="arg">value</em></dt>
1920 <dt>png:include-chunk=<em class="arg">value</em></dt>
1921 <dd>ancillary chunks to be excluded from or included in PNG output.
1923 <p>The <em class="arg">value</em> can be the name of a PNG chunk-type such
1924 as <em class="arg">bKGD</em>, a comma-separated list of chunk-types,
1925 or the word <em class="arg">all</em> or
1926 the word <em class="arg">none</em>. There must be no spaces in the
1927 list. Although PNG chunk-names are case-dependent, you can use
1928 all lowercase names if you prefer.</p>
1930 <p>The "include-chunk" and "exclude-chunk" lists only affect the behavior
1931 of the PNG encoder and have no effect on the PNG decoder.</p>
1933 <p>As a special case, if the <code>sRGB</code> chunk is excluded and
1934 the <code>gAMA</code> chunk is included, the <code>gAMA</code> chunk will
1935 only be written if gamma is not 1/2.2, since most decoders assume
1936 sRGB and gamma=1/2.2 when no colorspace information is included in
1937 the PNG file. Because the list is processed from left to right, you
1938 can achieve this with a single define:</p>
1941 -define png:include-chunk=none,gAMA
1944 <p>As a special case, if the <code>sRGB</code> chunk is not excluded and
1945 the PNG encoder recognizes that the image contains the sRGB ICC profile,
1946 the PNG encoder will write the <code>sRGB</code> chunk instead of the entire
1947 3144-byte ICC profile. To force the PNG encoder to write the sRGB
1948 profile as an <code>iCCP</code> chunk in the output PNG instead of the
1949 <code>sRGB</code> chunk, exclude the <code>sRGB</code> chunk.</p>
1951 <p>The critical PNG chunks <code>IHDR</code>, <code>PLTE</code>,
1952 <code>IDAT</code>, and <code>IEND</code> cannot be excluded. Any such
1953 entries appearing in the list will be ignored.</p>
1955 <p>If the ancillary PNG <code>tRNS</code> chunk is excluded and the
1956 image has transparency, the PNG colortype is forced to be 4 or 6
1957 (GRAY_ALPHA or RGBA). If the image is not transparent, then the
1958 <code>tRNS</code> chunk isn't written anyhow, and there is no effect
1959 on the PNG colortype of the output image.</p>
1961 <p>The <a href="command-line-options.html#strip">-strip</a> option does the equivalent of the
1962 following for PNG output:</p>
1965 -define png:include-chunk=none,trns,gama
1968 <p>The default behavior is to include all known PNG ancillary chunks
1969 plus ImageMagick's private <code>vpAg</code> ("virtual page") chunk,
1970 and to exclude all PNG chunks that are unknown to ImageMagick,
1971 regardless of their PNG "copy-safe" status as described in the
1972 PNG specification.</p>
1974 <p>Any chunk names that are not known to ImageMagick are ignored
1975 if they appear in either the "include-chunk" or "exclude-chunk" list.
1976 The ancillary chunks currently known to ImageMagick are
1977 <code>bKGD</code>, <code>cHRM</code>, <code>gAMA</code>, <code>iCCP</code>,
1978 <code>oFFs</code>, <code>pHYs</code>, <code>sRGB</code>, <code>tEXt</code>,
1979 <code>tRNS</code>, <code>vpAg</code>, and <code>zTXt</code>.</p>
1981 <p>You can also put <code>date</code> in the list to include or exclude
1982 the "Date:create" and "Date:modify" text chunks that ImageMagick normally
1983 inserts in the output PNG.</p>
1987 <dt>png:preserve-colormap</dt>
1988 <dd>Use the existing image->colormap. Normally the PNG encoder will
1989 try to optimize the palette, eliminating unused entries and putting
1990 the transparent colors first. If this flag is set, that behavior
1993 <dt>png:preserve-iCCP</dt>
1994 <dd>By default, the PNG decoder and encoder examine any ICC profile
1995 that is present, either from an <code>iCCP</code> chunk in the PNG
1996 input or supplied via an option, and if the profile is recognized
1997 to be the sRGB profile, converts it to the <code>sRGB</code> chunk.
1998 You can use <code>-define png:preserve-iCCP</code> to prevent
1999 this from happening; in such cases the <code>iCCP</code> chunk
2000 will be read or written and no <code>sRGB</code> chunk will be
2001 written. There are some ICC profiles that claim to be sRGB but
2002 have various errors that cause them to be rejected by libpng16; such
2003 profiles are recognized anyhow and converted to the <code>sRGB</code>
2004 chunk, but are rejected if the <code>-define png:preserve-iCCP</code>
2005 is present. Note that not all "sRGB" ICC profiles are recognized
2006 yet; we will add them to the list as we encounter them.</dd>
2008 <dt>ps:imagemask</dt>
2009 <dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create
2010 Postscript files that render bilevel images with the Postscript imagemask
2011 operator instead of the image operator.</dd>
2013 <dt>quantum:format=<em class="arg">type</em></dt>
2014 <dd>Set the type to <code>floating-point</code> to specify a floating-point
2015 format for raw files (e.g. GRAY:) or for MIFF and TIFF images in HDRI mode
2016 to preserve negative values. If <a href="command-line-options.html#depth">-depth</a> 16 is
2017 included, the result is a single precision floating point format.
2018 If <a href="command-line-options.html#depth">-depth</a> 32 is included, the result is
2019 double precision floating point format.</dd>
2021 <dt>quantum:polarity=<em class="arg">photometric-interpretation</em></dt>
2022 <dd>Set the photometric-interpretation of an image (typically for TIFF image
2023 file format) to either <code>min-is-black</code> (default) or
2024 <code>min-is-white</code>.</dd>
2026 <dt>sample:offset=<em class="arg">geometry</em></dt>
2027 <dd>Location of the sampling point within the sub-region being sampled,
2028 expressed as percentages (see <a href="command-line-options.html#sample">-sample</a>).</dd>
2030 <dt>showkernel=<em class="arg">1</em></dt>
2031 <dd>Outputs (to 'standard error') all the information about a generated <a href="command-line-options.html#morphology">-morphology</a> kernel.</dd>
2033 <dt>tiff:rows-per-strip=<em class="arg">value</em></dt>
2034 <dd>Sets the number of rows per strip</dd>
2036 <dt>tiff:tile-geometry=<em class="arg">WxH</em></dt>
2037 <dd>Sets the tile size for pyramid tiffs. Requires the suffix PTIF: before the
2041 <p>For example, to create a postscript file that will render only the black
2042 pixels of a bilevel image, use:</p>
2044 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p>
2045 <p>Set attributes of the image registry by prefixing the value with
2046 <code>registry:</code>. For example, to set a temporary path to put work files,
2050 -define registry:temporary-path=/data/tmp
2053 <p>If you want to keep the temporary files ImageMagick creates private, overwrite them with zeros or random data before they are removed. On the first pass, the file is zeroed. For subsequent passes, random data is written. For example, to specify two passes:</p>
2056 -define registry:shred-passes=2
2059 <div style="margin: auto;">
2060 <h4><a id="delay"></a>-delay <em class="arg">ticks</em> <br></br>-delay <em class="arg">ticks</em>x<em class="arg">ticks-per-second</em> {<em class="arg"><</em>} {<em class="arg">></em>}</h4>
2063 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">display the next image after pausing.</td><td style="text-align:right;"></td></tr></table>
2065 <p>This option is useful for regulating the animation of image sequences
2066 <em>ticks/ticks-per-second</em> seconds must expire before the display of the
2067 next image. The default is no delay between each showing of the image
2068 sequence. The default ticks-per-second is 100.</p>
2070 <p>Use <code>></code> to change the image delay <em>only</em> if its current
2071 value exceeds the given delay. <code><</code> changes the image delay
2072 <em>only</em> if current value is less than the given delay. For example, if
2073 you specify <code>30></code> and the image delay is 20, the image delay does
2074 not change. However, if the image delay is 40 or 50, the delay it is changed
2075 to 30. Enclose the given delay in quotation marks to prevent the
2076 <code><</code> or <code>></code> from being interpreted by your shell as
2077 a file redirection.</p>
2080 <div style="margin: auto;">
2081 <h4><a id="delete"></a>-delete <em class="arg">indexes</em></h4>
2084 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">delete the images specified by index, from the image sequence.</td><td style="text-align:right;"></td></tr></table>
2086 <p>Specify the image by its index in the sequence. The first image is index
2087 0. Negative indexes are relative to the end of the sequence, for example, -1
2088 represents the last image of the sequence. Specify a range of images with
2089 a dash (e.g. 0-4). Separate indexes with a comma (e.g. 0,2). Use
2090 <code>+delete</code> to delete the last image in the current image sequence.</p>
2093 <div style="margin: auto;">
2094 <h4><a id="density"></a>-density <em class="arg">width</em><br></br>-density <em class="arg">width</em>x<em class="arg">height</em></h4>
2097 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the horizontal and vertical resolution of an image for
2098 rendering to devices.</td><td style="text-align:right;"></td></tr></table>
2100 <p>This option specifies the image resolution to store while encoding a raster
2101 image or the canvas resolution while rendering (reading) vector formats such
2102 as Postscript, PDF, WMF, and SVG into a raster image. Image resolution
2103 provides the unit of measure to apply when rendering to an output device or
2104 raster image. The default unit of measure is in dots per inch (DPI). The <a href="command-line-options.html#units">-units</a> option may be used to select dots per centimeter
2107 <p>The default resolution is 72 dots per inch, which is equivalent to one
2108 point per pixel (Macintosh and Postscript standard). Computer screens are
2109 normally 72 or 96 dots per inch, while printers typically support 150, 300,
2110 600, or 1200 dots per inch. To determine the resolution of your display, use
2111 a ruler to measure the width of your screen in inches, and divide by the
2112 number of horizontal pixels (1024 on a 1024x768 display).</p>
2114 <p>If the file format supports it, this option may be used to update the
2115 stored image resolution. Note that Photoshop stores and obtains image
2116 resolution from a proprietary embedded profile. If this profile is not
2117 stripped from the image, then Photoshop will continue to treat the image using
2118 its former resolution, ignoring the image resolution specified in the standard
2121 <p>The <a href="command-line-options.html#density">-density</a> option sets an <em>attribute</em> and
2122 does not alter the underlying raster image. It may be used to adjust the
2123 rendered size for desktop publishing purposes by adjusting the scale applied
2124 to the pixels. To resize the image so that it is the same size at a different
2125 resolution, use the <a href="command-line-options.html#resample">-resample</a> option.</p>
2127 <div style="margin: auto;">
2128 <h4><a id="depth"></a>-depth <em class="arg">value</em></h4>
2131 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">depth of the image.</td><td style="text-align:right;"></td></tr></table>
2133 <p>This the number of bits in a color sample within a pixel. Use this option
2134 to specify the depth of raw images whose depth is unknown such as GRAY, RGB,
2135 or CMYK, or to change the depth of any image after it has been read.</p>
2137 <div style="margin: auto;">
2138 <h4><a id="descend"></a>-descend</h4>
2141 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">obtain image by descending window hierarchy.</td><td style="text-align:right;"></td></tr></table>
2143 <div style="margin: auto;">
2144 <h4><a id="deskew"></a>-deskew <em class="arg">threshold</em></h4>
2147 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">straighten an image. A threshold of 40% works for most images.</td><td style="text-align:right;"></td></tr></table>
2149 <p>Use <a href="command-line-options.html#set">-set</a> <code>option:deskew:auto-crop
2150 <em>width</em></code> to auto crop the image. The set argument is the pixel
2151 width of the image background (e.g 40).</p>
2153 <div style="margin: auto;">
2154 <h4><a id="despeckle"></a>-despeckle</h4>
2157 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">reduce the speckles within an image.</td><td style="text-align:right;"></td></tr></table>
2159 <div style="margin: auto;">
2160 <h4><a id="direction"></a>-direction <em class="arg">type</em></h4>
2163 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">render text right-to-left or left-to-right.</td><td style="text-align:right;"></td></tr></table>
2165 <div style="margin: auto;">
2166 <h4><a id="displace"></a>-displace <em class="arg">horizontal-scale</em><br></br>-displace <em class="arg">horizontal-scale</em>x<em class="arg">vertical-scale</em></h4>
2169 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">shift image pixels as defined by a displacement map.</td><td style="text-align:right;">[<a href="composite.html">composite</a>]</td></tr></table>
2171 <p>With this option, the 'overlay' image, and optionally the 'mask' image,
2172 is used as a displacement map, which is used to displace the lookup of
2173 what part of the 'background' image is seen at each point of the overlaid
2174 area. Much like the displacement map is a 'lens' that redirects light shining
2175 through it so as to present a distorted view the original 'background' image
2178 <p>Any perfect grey areas of the displacement map produce a zero
2179 displacement of the image. Black areas produce the given maximum negative
2180 displacement of the lookup point, while white produce a maximum positive
2181 displacement of the lookup. </p>
2183 <p>Note that it is the lookup of the 'background' that is displaced, not a
2184 displacement of the image itself. As such an area of the displacement map
2185 containing 'white' will have the lookup point 'shifted' by a positive amount,
2186 and thus generating a copy of the destination image to the right/downward from
2187 the correct position. That is the image will look like it may have been
2188 'shifted' in a negative left/upward direction. Understanding this is a very
2189 important in understanding how displacement maps work. </p>
2191 <p>The given arguments define the maximum amount of displacement in pixels
2192 that a particular map can produce. If the displacement scale is large enough
2193 it is also possible to lookup parts of the 'background' image that lie well
2194 outside the bounds of the displacement map itself. That is you could very
2195 easily copy a section of the original image from outside the overlay area
2196 into the overlay area. </p>
2198 <p>The '%' flag makes the displacement scale relative to the size of the
2199 overlay image (100% = half width/height of image). Using '!' switches
2200 percentage arguments to refer to the destination image size instead.
2201 these flags were added as of IM v6.5.3-5.</p>
2203 <p>Normally a single grayscale displacement map is provided, which with the
2204 given scaling values will determine a single direction (vector) in which
2205 displacements can occur (positively or negatively). However, if you also
2206 specify a third image which is normally used as a <em class="arg">mask</em>,
2207 the <em class="arg">composite image</em> is used for horizontal X
2208 displacement, while the <em class="arg">mask image</em> is used for vertical Y
2209 displacement. This allows you to define completely different displacement
2210 values for the X and Y directions, and allowing you to lookup any point within
2211 the <em class="arg">scale</em> bounds. In other words each pixel can lookup
2212 any other nearby pixel, producing complex 2 dimensional displacements, rather
2213 than a simple 1 dimensional vector displacements. </p>
2215 <p>Alternatively rather than supplying two separate images, as of IM v6.4.4-0,
2216 you can use the 'red' channel of the overlay image to specify the horizontal
2217 or X displacement, and the 'green' channel for the vertical or Y displacement.
2220 <p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a
2221 mask the transparency of the destination image. However areas outside the
2222 overlaid areas will not be effected. </p>
2225 <div style="margin: auto;">
2226 <h4><a id="display"></a>-display <em class="arg">host:display[.screen]</em></h4>
2229 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Specifies the X server to contact.</td><td style="text-align:right;">[<a href="animate.html">animate</a>, <a href="display.html">display</a>]</td></tr></table>
2231 <p>This option is used with convert for obtaining image or font from this
2232 X server. See <em class="arg">X(1)</em>.</p>
2234 <div style="margin: auto;">
2235 <h4><a id="dispose"></a>-dispose <em class="arg">method</em></h4>
2238 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">define the GIF disposal image setting for images that are being created or read in. </td><td style="text-align:right;"></td></tr></table>
2240 <p>The layer disposal method defines the way each the displayed image is to be
2241 modified after the current 'frame' of an animation has finished being
2242 displayed (after its 'delay' period), but before the next frame on an
2243 animation is to be overlaid onto the display. </p>
2245 <p>Here are the valid methods:</p>
2248 Undefined 0 No disposal specified (equivalent to '<code>none</code>').
2249 None 1 Do not dispose, just overlay next frame image.
2250 Background 2 Clear the frame area with the background color.
2251 Previous 3 Clear to the image prior to this frames overlay.
2254 <p>You can also use the numbers given above, which is what the GIF format
2255 uses internally to represent the above settings. </p>
2257 <p>To print a complete list of dispose methods, use <a href="command-line-options.html#list">-list dispose</a>.</p>
2259 <p>Use <a href="command-line-options.html#dispose">+dispose</a>, turn off the setting and prevent
2260 resetting the layer disposal methods of images being read in. </p>
2262 <p>Use <a href="command-line-options.html#set">-set</a> '<code>dispose</code>' method to set the image
2263 disposal method for images already in memory.</p>
2265 <div style="margin: auto;">
2266 <h4><a id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4>
2269 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">maximum RMSE for subimage match (default 0.2).</td><td style="text-align:right;">[<a href="compare.html">compare</a>]</td></tr></table>
2272 <div style="margin: auto;">
2273 <h4><a id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4>
2276 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">dissolve an image into another by the given percent.</td><td style="text-align:right;">[<a href="composite.html">composite</a>]</td></tr></table>
2278 <p>The opacity of the composite image is multiplied by the given percent, then
2279 it is composited 'over' the main image. If <em class="arg">src_percent</em>
2280 is greater than 100, start dissolving the main image so it becomes
2281 transparent at a value of '<code class="arg">200</code>'. If both percentages
2282 are given, each image are dissolved to the percentages given. </p>
2284 <p>Note that dissolve percentages do not add, two opaque images dissolved
2285 '50,50', produce a 75% transparency. For a 50% + 50% blending of the two
2286 images, you would need to use dissolve values of '50,100'. </p>
2288 <div style="margin: auto;">
2289 <h4><a id="distort"></a>-distort <em class="arg">method arguments</em></h4>
2292 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">distort an image, using the given <em class="arg">method</em> and its required <em class="arg">arguments</em>.</td><td style="text-align:right;"></td></tr></table>
2294 <p>The <em class="arg">arguments</em> is a single string containing a list
2295 of floating point numbers separated by commas or spaces. The number of
2296 and meaning of the floating point values depends on the distortion <em class="arg">method</em> being used. </p>
2298 <p>Choose from these distortion types:</p>
2302 <th align="left" style="width: 8%">Method</th>
2303 <th align="left">Description</th>
2307 <td valign="top"><code>ScaleRotateTranslate</code>
2308 <br></br>or <code>SRT</code></td>
2310 Distort image by first scaling and rotating about a given 'center',
2311 before translating that 'center' to the new location, in that order. It
2312 is an alternative method of specifying a '<code>Affine</code>' type of
2313 distortion, but without shearing effects. It also provides a good way
2314 of rotating and displacing a smaller image for tiling onto a larger
2315 background (IE 2-dimensional animations). <br></br>
2317 The number of arguments determine the specific meaning of each
2318 argument for the scales, rotation, and translation operations. <br></br>
2320 <table style="margin-left:auto; margin-right:auto;">
2321 <tr><td># </td><td>arguments meaning</td></tr>
2322 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr>
2323 <tr><td>2:</td><td><em>Scale Angle</em></td></tr>
2324 <tr><td>3:</td><td><em>X,Y Angle</em></td></tr>
2325 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr>
2327 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr>
2329 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr>
2331 <td><em>X,Y ScaleX,ScaleY Angle
2332 NewX,NewY</em></td></tr>
2335 This is actually an alternative way of specifying a 2 dimensional linear
2336 '<code>Affine</code>' or '<code>AffineProjection</code>' distortion. </td> </tr>
2339 <td valign="top"><code>Affine</code></td>
2341 Distort the image linearly by moving a list of at least 3 or more sets
2342 of control points (as defined below). Ideally 3 sets or 12 floating
2343 point values are given allowing the image to be linearly scaled,
2344 rotated, sheared, and translated, according to those three points. See
2345 also the related '<code>AffineProjection</code>' and '<code>SRT</code>'
2346 distortions. <br></br>
2348 More than 3 sets given control point pairs (12 numbers) is least
2349 squares fitted to best match a linear affine distortion. If only 2
2350 control point pairs (8 numbers) are given a two point image translation
2351 rotation and scaling is performed, without any possible shearing,
2352 flipping or changes in aspect ratio to the resulting image. If only one
2353 control point pair is provides the image is only translated, (which may
2354 be a floating point non-integer translation). <br></br>
2356 This distortion does not include any form of perspective distortion.
2362 <td valign="top"><code>AffineProjection</code></td>
2364 Linearly distort an image using the given Affine Matrix of 6
2365 pre-calculated coefficients forming a set of Affine Equations to map
2366 the source image to the destination image.
2368 <div style="text-align: center"><em>
2369 s<sub>x</sub>, r<sub>x</sub>,
2370 r<sub>y</sub>, s<sub>y</sub>,
2371 t<sub>x</sub>, t<sub>y</sub>
2374 See <a href="command-line-options.html#affine">-affine</a> setting for more detail, and
2375 meanings of these coefficients. <br></br>
2377 The distortions '<code>Affine</code>' and '<code>SRT</code>' provide
2378 alternative methods of defining this distortion, with ImageMagick doing
2379 the calculations needed to generate the required coefficients. You can
2380 see the internally generated coefficients, by using a <a href="command-line-options.html#verbose">-verbose</a> setting with those other variants. </td>
2385 <td valign="top"><code>BilinearForward</code><br></br>
2386 <code>BilinearReverse</code></td>
2388 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or
2389 16 values (see below). Not that lines may not appear straight after
2390 distortion, though the distance between coordinates will remain
2391 consistent. <br></br>
2393 The '<code>BilinearForward</code>' is used to map rectangles to any
2394 quadrilateral, while the '<code>BilinearReverse</code>' form maps any
2395 quadrilateral to a rectangle, while preserving the straight line edges
2396 in each case. <br></br>
2398 Note that '<code>BilinearForward</code>' can generate invalid pixels
2399 which will be colored using the <a href="command-line-options.html#mattecolor">-mattecolor</a>
2400 color setting. Also if the quadrilateral becomes 'flipped' the image
2401 may disappear. <br></br>
2403 There are future plans to produce a true Bilinear distortion that will
2404 attempt to map any quadrilateral to any other quadrilateral, while
2405 preserving edges (and edge distance ratios).
2411 <td valign="top"><code>Perspective</code></td>
2413 Perspective distort the images, using a list of 4 or more sets of
2414 control points (as defined below). More that 4 sets (16 numbers) of
2415 control points provide least squares fitting for more accurate
2416 distortions (for the purposes of image registration and panorama
2417 effects). Less than 4 sets will fall back to a '<code>Affine</code>'
2418 linear distortion. <br></br>
2420 Perspective Distorted images ensures that straight lines remain
2421 straight, but the scale of the distorted image will vary. The horizon
2422 is anti-aliased, and the 'sky' color may be set using the
2423 <a href="command-line-options.html#mattecolor">-mattecolor</a> setting. </td>
2427 <td valign="top"><code>PerspectiveProjection</code> </td>
2429 Do a '<code>Perspective</code>' distortion biased on a set of 8
2430 pre-calculated coefficients. You can get these coefficients by looking
2431 at the <a href="command-line-options.html#verbose">-verbose</a> output of a
2432 '<code>Perspective</code>' distortion, or by calculating them yourself.
2433 If the last two perspective scaling coefficients are zero, the
2434 remaining 6 represents a transposed 'Affine Matrix'. </td>
2439 <td valign="top"><code>Arc</code></td>
2441 Arc the image (variation of polar mapping) over the angle given around
2443 <table width="90%" style="margin-left: auto; margin-right: auto;">
2444 <tr valign="top"><td>Argument</td>
2445 <td>Meaning</td></tr>
2446 <tr valign="top"><td><em>arc_angle</em></td>
2447 <td>The angle over which to arc the image side-to-side</td></tr>
2448 <tr valign="top"><td><em>rotate_angle</em></td>
2449 <td>Angle to rotate resulting image from vertical center</td></tr>
2450 <tr valign="top"><td><em>top_radius</em></td>
2451 <td>Set top edge of source image at this radius</td></tr>
2452 <tr valign="top"><td><em>bottom_radius</em> </td>
2453 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2456 The resulting image is always resized to best fit the resulting image,
2457 (as if using <a href="command-line-options.html#distort">+distort</a>) while attempting to
2458 preserve scale and aspect ratio of the original image as much as
2459 possible with the arguments given by the user. All four arguments will
2460 be needed to change the overall aspect ratio of an 'Arc'ed image. <br></br>
2462 This a variation of a polar distortion designed to try to preserve the
2463 aspect ratio of the image rather than direct Cartesian to Polar
2468 <td valign="top"><code>Polar</code></td>
2470 Like '<code>Arc</code>' but do a complete Cartesian to Polar mapping of
2471 the image. that is the height of the input image is mapped to the
2472 radius limits, while the width is wrapped around between the
2473 angle limits. <br></br>
2475 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br></br>
2477 All arguments are optional. With <em>Rmin</em> defaulting to zero, the
2478 center to the center of the image, and the angles going from -180 (top)
2479 to +180 (top). If <em>Rmax</em> is given the special value of
2480 '<code>0</code>', the the distance from the center to the nearest edge
2481 is used for the radius of the output image, which will ensure the whole
2482 image is visible (though scaled smaller). However a special value of
2483 '<code>-1</code>' will use the distance from the center to the furthest
2484 corner, This may 'clip' the corners from the input rectangular image,
2485 but will generate the exact reverse of a '<code>DePolar</code>' with
2486 the same arguments. <br></br>
2488 If the plus form of distort (<a href="command-line-options.html#distort">+distort</a>) is used
2489 output image center will default to <code>0,0</code> of the virtual
2490 canvas, and the image size adjusted to ensure the whole input image is
2491 made visible in the output image on the virtual canvas. </td>
2496 <td valign="top"><code>DePolar</code></td>
2498 Uses the same arguments and meanings as a '<code>Polar</code>' distortion
2499 but generates the reverse Polar to Cartesian distortion. <br></br>
2501 The special <em>Rmax</em> setting of '<code>0</code>' may however clip
2502 the corners of the input image. However using the special
2503 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner
2504 distance) will ensure the whole distorted image is preserved in the
2505 generated result, so that the same argument to '<code>Polar</code>' will
2506 reverse the distortion re-producing the original.
2508 Note that as this distortion requires the area resampling of a circular
2509 arc, which can not be handled by the builtin EWA resampling function.
2510 As such the normal EWA filters are turned off. It is recommended some
2511 form of 'super-sampling' image processing technique be used to produce
2512 a high quality result. </td>
2517 <td valign="top"><code>Barrel</code></td>
2519 Given the four coefficients (A,B,C,D) as defined by <a href="http://wiki.panotools.org/Lens_correction_model">Helmut
2520 Dersch</a>, perform a barrel or pin-cushion distortion appropriate to
2521 correct radial lens distortions. That is in photographs, make straight
2522 lines straight again. <br></br>
2524 Arguments: <em>A B C</em> [ <em>D</em> [
2525 <em>X</em> , <em>Y</em> ] ] <br></br>
2526 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub>
2527 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em>
2528 [ <em>X</em> , <em>Y</em> ] <br></br>
2529 So that it forms the function <br></br>
2530 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2531 <em>C</em>*r + <em>D</em> )<br></br>
2533 Where <em>X</em>,<em>Y</em> is the optional center of the distortion
2534 (defaulting to the center of the image). <br></br>
2535 The second form is typically used to distort images, rather than
2536 correct lens distortions. <br></br>
2542 <td valign="top"><code>BarrelInverse</code></td>
2544 This is very similar to '<code>Barrel</code>' with the same set of
2545 arguments, and argument handling. However it uses the inverse
2546 of the radial polynomial,
2547 so that it forms the function <br></br>
2548 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2549 <em>C</em>*r + <em>D</em> )<br></br>
2550 Note that this is not the reverse of the '<code>Barrel</code>'
2551 distortion, just a different barrel-like radial distortion method.
2557 <td valign="top"><code>Shepards</code></td>
2559 Distort the given list control points (any number) using an Inverse
2560 Squared Distance Interpolation Method (<a href="http://en.wikipedia.org/wiki/Shepard%27s_method">Shepards
2561 Method</a>). The control points in effect do 'localized' displacement
2562 of the image around the given control point (preserving the look and
2563 the rotation of the area near the control points. For best results
2564 extra control points should be added to 'lock' the positions of the
2565 corners, edges and other unchanging parts of the image, to prevent
2566 their movement. <br></br>
2568 The distortion has been likened to 'taffy pulling' using nails, or
2569 pins' stuck in a block of 'jelly' which is then moved to the new
2570 position, distorting the surface of the jelly. <br></br>
2572 Internally it is equivalent to generating a displacement map (see <a href="command-line-options.html#displace">-displace</a>) for source image color look-up using
2573 the <a href="command-line-options.html#sparse-color">-sparse-color</a> method of the same name.
2580 <p>To print a complete list of distortion methods, use <a href="command-line-options.html#list">-list
2583 <p>Many of the above distortion methods such as '<code>Affine</code>',
2584 '<code>Perspective</code>', and '<code>Shepards</code>' use a list control points
2585 defining how these points in the given image should be distorted in the
2586 destination image. Each set of four floating point values represent a source
2587 image coordinate, followed immediately by the destination image coordinate.
2588 This produces a list of values such as...</p>
2589 <div style="text-align: center"><em>
2590 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub>
2591 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub>
2592 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub>
2594 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub>
2596 <p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the
2597 destination image. </p>
2599 <p>For example, to warp an image using '<code>perspective</code>' distortion,
2600 needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2601 perspective distortion of the built-in "rose:" image. Note how spaces were
2602 used to group the 4 sets of coordinate pairs, to make it easier to read and
2605 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">
2606 convert rose: -virtual-pixel black \<br></br>
2607 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \<br></br>
2608 rose_3d_rotated.gif</span></p>
2609 <p>If more that the required number of coordinate pairs are given for
2610 a distortion, the distortion method is 'least squares' fitted to produce the
2611 best result for all the coordinate pairs given. If less than the ideal number
2612 of points are given, the distort will generally fall back to a simpler form of
2613 distortion that can handles the smaller number of coordinates (usually a linear
2614 '<code>Affine</code>' distortion). </p>
2616 <p>By using more coordinates you can make use of image registration tool to
2617 find matching coordinate pairs in overlapping images, so as to improve the
2618 'fit' of the distortion. Of course a bad coordinate pair can also make the
2619 'fit' worse. Caution is always advised. </p>
2621 <p>Colors are acquired from the source image according to a cylindrical
2622 resampling <a href="command-line-options.html#filter">-filter</a>, using a special technique known as
2623 EWA resampling. This produces very high quality results, especially when
2624 images become smaller (minified) in the output, which is very common when
2625 using '<code>perspective</code>' distortion. For example here we view
2626 a infinitely tiled 'plane' all the way to the horizon. </p>
2628 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">
2629 convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \<br></br>
2630 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \<br></br>
2631 checks_tiled.jpg</span></p>
2632 <p>Note that a infinitely tiled perspective images involving the horizon can
2633 be very slow, because of the number of pixels that are compressed to generate
2634 each individual pixel close to the 'horizon'. You can turn off EWA
2635 resampling, by specifing the special <a href="command-line-options.html#filter">-filter</a> setting of
2636 '<code>point</code>' (recommended if you plan to use super-sampling instead).
2639 <p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2640 example, <a href="command-line-options.html#distort">-distort</a> will use the current <a href="command-line-options.html#mattecolor">-mattecolor</a> setting for these pixels. If you do not
2641 what these pixels to be visible, set the color to match the rest of the
2644 <p>The output image size will by default be the same as the input image. This
2645 means that if the part of the distorted image falls outside the viewed area of
2646 the 'distorted space', those parts is clipped and lost. However if you use
2647 the plus form of the operator (<a href="command-line-options.html#distort">+distort</a>) the operator
2648 will attempt (if possible) to show the whole of the distorted image, while
2649 retaining a correct 'virtual canvas' offset, for image layering. This offset
2650 may need to be removed using <a href="command-line-options.html#repage">+repage</a>, to remove if it
2653 <p>Setting <a href="command-line-options.html#verbose">-verbose</a> setting, will cause <a href="command-line-options.html#distort">-distort</a> to attempt to output the internal coefficients,
2654 and the <a href="command-line-options.html#fx">-fx</a> equivalent to the distortion, for expert study,
2655 and debugging purposes. This many not be available for all distorts. </p>
2657 <p>You can alternatively specify a special "<code><a href="command-line-options.html#define">-define</a> distort:viewport={geometry_string}</code>" setting which will
2658 specify the size and the offset of the generated 'viewport' image of the
2659 distorted image space.</p>
2661 <p>Setting a "<code><a href="command-line-options.html#define">-define</a>
2662 distort:scale={scale_factor}</code>" will scale the output image (viewport or
2663 otherwise) by that factor without changing the viewed contents of the
2664 distorted image. This can be used either for 'super-sampling' the image for
2665 a higher quality result, or for panning and zooming around the image (with
2666 appropriate viewport changes, or post-distort cropping and resizing). </p>
2668 <p>Setting "<code><a href="command-line-options.html#define">-define</a> resample:verbose=1</code>"
2669 will output the cylindrical filter lookup table created by the EWA (Elliptical
2670 Weighted Average) resampling algorithm. Note this table uses a squared radius
2671 lookup value. This is typically only used for debugging EWA resampling. </p>
2674 <div style="margin: auto;">
2675 <h4><a id="distribute-cache"></a>-distribute-cache <em class="arg">port</em></h4>
2678 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">launch a distributed pixel cache server. </td><td style="text-align:right;"></td></tr></table>
2680 <div style="margin: auto;">
2681 <h4><a id="dither"></a>-dither <em class="arg">method</em></h4>
2684 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Apply a Riemersma or Floyd-Steinberg error diffusion dither to
2685 images when general color reduction is applied via an option, or automagically
2686 when saving to specific formats. This enabled by default. </td><td style="text-align:right;"></td></tr></table>
2688 <p>Dithering places two or more colors in neighboring pixels so that to the
2689 eye a closer approximation of the images original color is reproduced. This
2690 reduces the number of colors needed to reproduce the image but at the cost of
2691 a lower level pattern of colors. Error diffusion dithers can use any set of
2692 colors (generated or user defined) to an image. </p>
2694 <p>Dithering is turned on by default, to turn it off use the plus form of the
2695 setting, <a href="command-line-options.html#dither">+dither</a>. This will also also render PostScript
2696 without text or graphic aliasing. Disabling dithering often (but not always)
2697 leads to faster process, a smaller number of colors, but more cartoon like
2698 image coloring. Generally resulting in 'color banding' effects in areas with
2699 color gradients. </p>
2701 <p>The color reduction operators <a href="command-line-options.html#colors">-colors</a>, <a href="command-line-options.html#monochrome">-monochrome</a>, <a href="command-line-options.html#remap ">-remap</a>, and <a href="command-line-options.html#posterize">-posterize</a>, apply dithering to images using the reduced
2702 color set they created. These operators are also used as part of automatic
2703 color reduction when saving images to formats with limited color support, such
2704 as <code>GIF:</code>, <code>XBM:</code>, and others, so dithering may also be used
2705 in these cases. </p>
2707 <p>Alternatively you can use <a href="command-line-options.html#random-threshold">-random-threshold</a>
2708 to generate purely random dither. Or use <a href="command-line-options.html#ordered-dither">-ordered-dither</a> to apply threshold mapped dither
2709 patterns, using uniform color maps, rather than specific color maps. </p>
2712 <div style="margin: auto;">
2713 <h4><a id="draw"></a>-draw <em class="arg">string</em></h4>
2716 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Annotate an image with one or more graphic primitives.</td><td style="text-align:right;"></td></tr></table>
2718 <p>Use this option to annotate or decorate an image with one or more graphic
2719 primitives. The primitives include shapes, text, transformations, and pixel
2722 <p>The shape primitives:</p>
2727 rectangle x0,y0 x1,y1
2728 roundRectangle x0,y0 x1,y1 wc,hc
2729 arc x0,y0 x1,y1 a0,a1
2730 ellipse x0,y0 rx,ry a0,a1
2732 polyline x0,y0 ... xn,yn
2733 polygon x0,y0 ... xn,yn
2734 bezier x0,y0 ... xn,yn
2735 path path specification
2736 image operator x0,y0 w,h filename
2739 <p>The text primitive:</p>
2744 <p>The text gravity primitive:</p>
2747 gravity NorthWest, North, NorthEast, West, Center,
2748 East, SouthWest, South, or SouthEast
2751 <p>The text gravity primitive only affects the placement of text and does not
2752 interact with the other primitives. It is equivalent to using the <a href="command-line-options.html#gravity">-gravity</a> command-line option, except that it is limited in
2753 scope to the <a href="command-line-options.html#draw">-draw</a> option in which it appears.</p>
2755 <p>The transformation primitives:</p>
2765 <p>The pixel operation primitives:</p>
2772 <p>The shape primitives are drawn in the color specified by the preceding <a href="command-line-options.html#fill">-fill</a> setting. For unfilled shapes, use <a href="command-line-options.html#fill">-fill none</a>. You can optionally control the stroke (the
2773 "outline" of a shape) with the <a href="command-line-options.html#stroke">-stroke</a> and <a href="command-line-options.html#strokewidth">-strokewidth</a> settings.</p>
2775 <p>A <code>point</code> primitive is specified by a single <em>point</em> in the
2776 pixel plane, that is, by an ordered pair of integer coordinates,
2777 <em>x</em>,<em>y</em>. (As it involves only a single pixel, a <code>point</code>
2778 primitive is not affected by <a href="command-line-options.html#stroke">-stroke</a> or <a href="command-line-options.html#strokewidth">-strokewidth</a>.)</p>
2780 <p>A <code>line</code> primitive requires a start point and end point.</p>
2782 <p>A <code>rectangle</code> primitive is specified by the pair of points at the
2783 upper left and lower right corners.</p>
2785 <p>A <code>roundRectangle</code> primitive takes the same corner points as
2786 a <code>rectangle</code> followed by the width and height of the rounded corners
2789 <p>The <code>circle</code> primitive makes a disk (filled) or circle (unfilled).
2790 Give the center and any point on the perimeter (boundary).</p>
2792 <p>The <code>arc</code> primitive is used to inscribe an elliptical segment in
2793 to a given rectangle. An <code>arc</code> requires the two corners used for
2794 <code>rectangle</code> (see above) followed by the start and end angles of the
2795 arc of the segment segment (e.g. 130,30 200,100 45,90). The start and end
2796 points produced are then joined with a line segment and the resulting segment
2797 of an ellipse is filled.</p>
2799 <p>Use <code>ellipse</code> to draw a partial (or whole) ellipse. Give the
2800 center point, the horizontal and vertical "radii" (the <em>semi-axes</em> of
2801 the ellipse) and start and end angles in degrees (e.g. 100,100 100,150
2804 <p>The <code>polyline</code> and <code>polygon</code> primitives require three or
2805 more points to define their perimeters. A <code>polyline</code> is simply
2806 a <code>polygon</code> in which the final point is not stroked to the start
2807 point. When unfilled, this is a <em>polygonal line</em>. If the <a href="command-line-options.html#stroke">-stroke</a> setting is <code>none</code> (the default), then
2808 a <code>polyline</code> is identical to a <code>polygon</code>. </p>
2810 <p>A <em>coordinate</em> is a pair of integers separated by a space or
2811 optional comma. </p>
2813 <p>As an example, to define a circle centered at 100,100 that extends to
2817 -draw 'circle 100,100 150,150'
2820 <p>The <code>Bezier</code> primitive creates a spline curve and requires three
2821 or points to define its shape. The first and last points are the
2822 <em>knots</em> and these points are attained by the curve, while any
2823 intermediate coordinates are <em>control points</em>. If two control points
2824 are specified, the line between each end knot and its sequentially respective
2825 control point determines the tangent direction of the curve at that end. If
2826 one control point is specified, the lines from the end knots to the one
2827 control point determines the tangent directions of the curve at each end. If
2828 more than two control points are specified, then the additional control points
2829 act in combination to determine the intermediate shape of the curve. In order
2830 to draw complex curves, it is highly recommended either to use the
2831 <code>path</code> primitive or to draw multiple four-point bezier segments with
2832 the start and end knots of each successive segment repeated. For example:</p>
2835 -draw 'bezier 20,50 45,100 45,0 70,50'
2838 -draw 'bezier 70,50 95,100 95,0 120,50'
2842 <p>A <code>path</code> represents an outline of an object, defined in terms of
2843 moveto (set a new current point), lineto (draw a straight line), curveto (draw
2844 a Bezier curve), arc (elliptical or circular arc) and closepath (close the
2845 current shape by drawing a line to the last moveto) elements. Compound paths
2846 (i.e., a path with subpaths, each consisting of a single moveto followed by
2847 one or more line or curve operations) are possible to allow effects such as
2848 <em>donut holes</em> in objects. (See <a href="http://www.w3.org/TR/SVG/paths.html">Paths</a>.)</p>
2850 <p>Use <code>image</code> to composite an image with another image. Follow the
2851 image keyword with the composite operator, image location, image size, and
2855 -draw 'image SrcOver 100,100 225,225 image.jpg'
2858 <p>You can use 0,0 for the image size, which means to use the actual
2859 dimensions found in the image header. Otherwise, it is scaled to the given
2860 dimensions. See <a href="compose.html">Alpha Compositing</a> for
2861 a detailed discussion of alpha composition methods that are available. </p>
2863 <p>The "special augmented compose operators" such as "dissolve" that require
2864 arguments cannot be used at present with the <code>-draw image</code> option.
2867 <p>Use <code>text</code> to annotate an image with text. Follow the text
2868 coordinates with a string. If the string has embedded spaces, enclose it in
2869 single or double quotes.</p>
2871 <p>For example, the following annotates the image with <code>Works like
2872 magick!</code> for an image titled <code>bird.miff</code>. </p>
2875 -draw "text 100,100 'Works like magick!' "
2878 <p>See the <a href="command-line-options.html#annotate">-annotate</a> option for another convenient way
2879 to annotate an image with text.</p>
2881 <p>The <code>rotate</code> primitive rotates subsequent shape primitives and
2882 text primitives about the origin of the main image. If the <a href="command-line-options.html#region">-region</a> option precedes the <a href="command-line-options.html#draw">-draw</a>
2883 option, the origin for transformations is the upper left corner of the
2886 <p>The <code>translate</code> primitive translates subsequent shape and text
2889 <p>The <code>scale</code> primitive scales them.</p>
2891 <p>The <code>skewX</code> and <code>skewY</code> primitives skew them with respect
2892 to the origin of the main image or the region.</p>
2894 <p>The transformations modify the current affine matrix, which is initialized
2895 from the initial affine matrix defined by the <a href="command-line-options.html#affine">-affine</a>
2896 option. Transformations are cumulative within the <a href="command-line-options.html#draw">-draw</a>
2897 option. The initial affine matrix is not affected; that matrix is only changed
2898 by the appearance of another <a href="command-line-options.html#affine">-affine</a> option. If another
2899 <a href="command-line-options.html#draw">-draw</a> option appears, the current affine matrix is
2900 reinitialized from the initial affine matrix.</p>
2902 <p>Use the <code>color</code> primitive to change the color of a pixel to the
2903 fill color (see <a href="command-line-options.html#fill">-fill</a>). Follow the pixel coordinate with
2914 <p>Consider the target pixel as that specified by your coordinate. The
2915 <code>point</code> method recolors the target pixel. The <code>replace</code>
2916 method recolors any pixel that matches the color of the target pixel.
2917 <code>Floodfill</code> recolors any pixel that matches the color of the target
2918 pixel and is a neighbor, whereas <code>filltoborder</code> recolors any neighbor
2919 pixel that is not the border color. Finally, <code>reset</code> recolors all
2922 <p>Use <code>matte</code> to the change the pixel matte value to transparent.
2923 Follow the pixel coordinate with a method (see the <code>color</code> primitive
2924 for a description of methods). The <code>point</code> method changes the matte
2925 value of the target pixel. The <code>replace</code> method changes the matte
2926 value of any pixel that matches the color of the target pixel.
2927 <code>Floodfill</code> changes the matte value of any pixel that matches the
2928 color of the target pixel and is a neighbor, whereas <code>filltoborder</code>
2929 changes the matte value of any neighbor pixel that is not the border color (<a href="command-line-options.html#bordercolor">-bordercolor</a>). Finally <code>reset</code> changes the
2930 matte value of all pixels.</p>
2932 <p>You can set the primitive color, font, and font bounding box color with <a href="command-line-options.html#fill">-fill</a>, <a href="command-line-options.html#font">-font</a>, and <a href="command-line-options.html#box">-box</a>
2933 respectively. Options are processed in command line order so be sure to use
2934 these options <em>before</em> the <a href="command-line-options.html#draw">-draw</a> option.</p>
2936 <p>Strings that begin with a number must be quoted (e.g. use '1.png' rather
2939 <p>Drawing primitives conform to the <a href="magick-vector-graphics.html">Magick
2940 Vector Graphics</a> format.</p>
2943 <div style="margin: auto;">
2944 <h4><a id="duplicate"></a>-duplicate <em class="arg">count,indexes</em></h4>
2947 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">duplicate an image one or more times.</td><td style="text-align:right;"></td></tr></table>
2949 <p>Specify the count and the image to duplicate by its index in the sequence.
2950 The first image is index 0. Negative indexes are relative to the end of the
2951 sequence, for example, -1 represents the last image of the sequence. Specify
2952 a range of images with a dash (e.g. 0-4). Separate indexes with a comma (e.g.
2953 0,2). Use <code>+duplicate</code> to duplicate the last image in the current
2956 <div style="margin: auto;">
2957 <h4><a id="edge"></a>-edge <em class="arg">radius</em></h4>
2960 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">detect edges within an image.</td><td style="text-align:right;"></td></tr></table>
2962 <div style="margin: auto;">
2963 <h4><a id="emboss"></a>-emboss <em class="arg">radius</em></h4>
2966 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">emboss an image.</td><td style="text-align:right;"></td></tr></table>
2968 <div style="margin: auto;">
2969 <h4><a id="encipher"></a>-encipher <em class="arg">filename</em></h4>
2972 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Encipher pixels for later deciphering by <a href="command-line-options.html#decipher">-decipher</a>.</td><td style="text-align:right;"></td></tr></table>
2974 <p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
2976 <p>For more information, see the webpage, <a href="../www/cipher.html">ImageMagick: Encipher or
2977 Decipher an Image</a>.</p>
2981 <div style="margin: auto;">
2982 <h4><a id="encoding"></a>-encoding <em class="arg">type</em></h4>
2985 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">specify the text encoding.</td><td style="text-align:right;"></td></tr></table>
2987 <p>Choose from <code>AdobeCustom</code>, <code>AdobeExpert</code>,
2988 <code>AdobeStandard</code>, <code>AppleRoman</code>, <code>BIG5</code>,
2989 <code>GB2312</code>, <code>Latin 2</code>, <code>None</code>, <code>SJIScode</code>,
2990 <code>Symbol</code>, <code>Unicode</code>, <code>Wansung</code>.</p>
2992 <div style="margin: auto;">
2993 <h4><a id="endian"></a>-endian <em class="arg">type</em></h4>
2996 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Specify endianness (<code>MSB</code> or <code>LSB</code>) of the image.</td><td style="text-align:right;"></td></tr></table>
2998 <p>To print a complete list of endian types, use the <a href="command-line-options.html#list">-list endian</a> option.</p>
3000 <p>Use <a href="command-line-options.html#endian">+endian</a> to revert to unspecified endianness.</p>
3003 <div style="margin: auto;">
3004 <h4><a id="enhance"></a>-enhance</h4>
3007 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Apply a digital filter to enhance a noisy image.</td><td style="text-align:right;"></td></tr></table>
3010 <div style="margin: auto;">
3011 <h4><a id="equalize"></a>-equalize</h4>
3014 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">perform histogram equalization on the image channel-by-channel.</td><td style="text-align:right;"></td></tr></table>
3016 <p>To perform histogram equalization on all channels in concert, transform the
3017 image into some other color space, such as HSL, OHTA, YIQ or YUV, then
3018 equalize the appropriate intensity-like channel, then convert back to RGB.</p>
3020 <p>For example using HSL, we have: ... <code>-colorspace HSL -channel lightness
3021 -equalize -colorspace RGB</code> ...</p>
3023 <p>For YIQ, YUV and OHTA use the red channel. For example, OHTA is a principal
3024 components transformation that puts most of the information in the first
3025 channel. Here we have ... <code>-colorspace OHTA -channel red -equalize
3026 -colorspace RGB</code> ...</p>
3028 <div style="margin: auto;">
3029 <h4><a id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4>
3032 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Alter channel pixels by evaluating an arithmetic, relational, or logical expression.</td><td style="text-align:right;"></td></tr></table>
3034 <p>(See the <a href="command-line-options.html#function">-function</a> operator for some
3035 multi-parameter functions. See the <a href="command-line-options.html#fx">-fx</a> operator if more
3036 elaborate calculations are needed.)</p>
3038 <p>The behaviors of each <em class="arg">operator</em> are summarized in the
3039 following list. For brevity, the numerical value of a "pixel" referred to
3040 below is the value of the corresponding channel of that pixel, while
3041 a "normalized pixel" is that number divided by the maximum
3042 (installation-dependent) value <em class="QR">QuantumRange</em>. (If
3043 normalized pixels are used, they are restored, following the other
3044 calculations, to the full range by multiplying by <em class="QR">QuantumRange</em>.)</p>
3047 <col width="25%"></col>
3048 <col width="75%"></col>
3051 <th><em class="arg">operator</em></th>
3052 <th>Summary (see further below for details)</th>
3057 <tr><td>Abs </td> <td>Add <em class="arg">value</em> to pixels and return absolute value. </td></tr>
3058 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr>
3059 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr>
3060 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr>
3061 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
3062 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr>
3063 <tr><td>Exp </td> <td>base-e exponential function</td></tr>
3064 <tr><td>Exponential </td> <td>base-e exponential function</td></tr>
3065 <tr><td>LeftShift </td> <td>Shift the pixel values left by <em class="arg">value</em> bits (i.e., multiply pixels by 2<sup><em class="arg">value</em></sup>).</td></tr>
3066 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
3067 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr>
3068 <tr><td>Mean </td> <td>Add the <em class="arg">value</em> and divide by 2.</td></tr>
3069 <tr><td>Median </td> <td>Choose the median value from an image sequence.</td></tr>
3070 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr>
3071 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr>
3072 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr>
3073 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr>
3074 <tr><td>RightShift </td> <td>Shift the pixel values right by <em class="arg">value</em> bits (i.e., divide pixels by 2<sup><em class="arg">value</em></sup>).</td></tr>
3075 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr>
3076 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
3077 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr>
3078 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr>
3082 <tr><td>Gaussian-noise</td></tr>
3083 <tr><td>Impulse-noise</td></tr>
3084 <tr><td>Laplacian-noise</td></tr>
3085 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="command-line-options.html#noise">-noise</a> operators.)</td></tr>
3086 <tr><td>PoissonNoise</td></tr>
3087 <tr><td>Uniform-noise</td></tr>
3091 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr>
3092 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr>
3093 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr>
3097 <p>The specified functions are applied only to each previously set <a href="command-line-options.html#channel">-channel</a> in the image. If necessary, the results of the
3098 calculations are truncated (clipped) to fit in the interval [0, <em class="QR">QuantumRange</em>]. The transparency channel of the image is
3099 represented as a 'alpha' values (0 = fully transparent), so, for example, a
3100 <code>Divide</code> by 2 of the alpha channel will make the image
3101 semi-transparent. Append the percent symbol '<code>%</code>' to specify a value
3102 as a percentage of the <em class="QR">QuantumRange</em>.</p>
3104 <p>To print a complete list of <a href="command-line-options.html#evaluate">-evaluate</a> operators, use
3105 <a href="command-line-options.html#list">-list evaluate</a>.</p>
3107 <p>The results of the <code>Add</code>, <code>Subtract</code> and
3108 <code>Multiply</code> methods can also be achieved using either the <a href="command-line-options.html#level">-level</a> or the <a href="command-line-options.html#level">+level</a> operator, with
3109 appropriate argument, to linearly modify the overall range of color values.
3110 Please note, however, that <a href="command-line-options.html#level">-level</a> treats transparency as
3111 'matte' values (0 = opaque), while <a href="command-line-options.html#level">-evaluate</a> works with
3114 <p><code>AddModulus</code> has been added as of ImageMagick 6.4.8-4 and provides
3115 addition modulo the <em class="QR">QuantumRange</em>. It is therefore
3116 equivalent to <code>Add</code> unless the resulting pixel value is outside the
3117 interval [0, <em class="QR">QuantumRange</em>]. </p>
3119 <p><code>Exp or Exponential</code> has been added as of ImageMagick 6.6.5-1 and
3120 works on normalized pixel values. The <em class="arg">value</em> used with
3121 <code>Exp</code> should be negative so as to produce a decaying exponential
3122 function. Non-negative values will always produce results larger unity and
3123 thus outside the interval [0, <em class="QR">QuantumRange</em>]. The
3124 formula is expressed below. </p>
3126 <div style="text-align:center;">
3127 exp(<em class="arg">value</em> × <b><em>u</em></b>)
3130 <p> If the input image is squared, for example, using <a href="command-line-options.html#-function">-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be
3133 <p><code>Log</code> has been added as of ImageMagick 6.4.2-1 and works on
3134 normalized pixel values. This a <em>scaled</em> log function. The <em class="arg">value</em> used with <code>Log</code> provides a <em>scaling
3135 factor</em> that adjusts the curvature in the graph of the log function. The
3136 formula applied to a normalized value <b><em>u</em></b> is below. </p>
3138 <div style="text-align:center;">
3139 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1)
3142 <p><code>Pow</code> has been added as of ImageMagick 6.4.1-9, and works on
3143 normalized pixel values. Note that <code>Pow</code> is related to the <a href="command-line-options.html#gamma">-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
3144 to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
3145 with <a href="command-line-options.html#gamma">-gamma</a> is simply the reciprocal of the value used
3146 with <code>Pow</code>.</p>
3148 <p><code>Cosine</code> and <code>Sine</code> was added as of IM v6.4.8-8 and
3149 converts the image values into a value according to a (co)sine wave function.
3150 The synonyms <code>Cos</code> and <code>Sin</code> may also be used. The output
3151 is biased 50% and normalized by 50% so as to fit in the respective color value
3152 range. The <em class="arg">value</em> scaling of the <em>period</em> of the
3153 function (its frequency), and thus determines the number of 'waves' that will
3154 be generated over the input color range. For example, if the <em class="arg">value</em> is 1, the effective period is simply the <em class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2,
3155 then the effective period is the <em>half</em> the <em class="QR">QuantumRange</em>.</p>
3157 <div style="text-align:center;">
3158 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>).
3161 <p>See also the <a href="command-line-options.html#function">-function</a> operator, which is a
3162 multi-value version of evaluate. </p>
3164 <div style="margin: auto;">
3165 <h4><a id="evaluate-sequence"></a>-evaluate-sequence <em class="arg">operator</em></h4>
3168 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Alter channel pixels by evaluating an arithmetic, relational, or
3169 logical expression over a sequence of images.</td><td style="text-align:right;"></td></tr></table>
3171 <p>To print a complete list of <a href="command-line-options.html#evaluate-sequence">-evaluate-sequence</a> operators, use <a href="command-line-options.html#list">-list evaluate</a>.</p>
3173 <div style="margin: auto;">
3174 <h4><a id="extent"></a>-extent <em class="arg">geometry</em></h4>
3177 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the image size and offset.</td><td style="text-align:right;"></td></tr></table>
3179 <p>If the image is enlarged, unfilled areas are set to the background color.
3180 To position the image, use offsets in the <em class="arg">geometry</em>
3181 specification or precede with a <a href="command-line-options.html#gravity">-gravity</a> setting. To
3182 specify how to compose the image with the background, use <a href="command-line-options.html#compose">-compose</a>.</p>
3184 <p>This command reduces or expands a JPEG image to fit on an 800x600
3185 display. If the aspect ratio of the input image isn't exactly 4:3, then the
3186 image is centered on an 800x600 black canvas: </p>
3188 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert input.jpg -resize 800x600 -background black -compose Copy \ <br></br> -gravity center -extent 800x600 -quality 92 output.jpg</span></p>
3191 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3193 <div style="margin: auto;">
3194 <h4><a id="extract"></a>-extract <em class="arg">geometry</em></h4>
3197 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Extract the specified area from image.</td><td style="text-align:right;"></td></tr></table>
3199 <p>This option is most useful for extracting a subregion of a very large raw
3200 image. Note that these two commands are equivalent:</p>
3202 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 \ <br></br> image.rgb image.png</span><span class="crtout"></span><span class="crtprompt"> $ </span><span class="crtin">convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' \ <br></br> image.rgb image.png</span></p><p>If you omit the offsets, as in</p>
3204 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert -size 16000x16000 -depth 8 -extract 640x480 \ <br></br> image.rgb image.png</span></p>
3205 <p>the image is <em>resized</em> to the specified dimensions instead,
3208 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p>
3209 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3211 <div style="margin: auto;">
3212 <h4><a id="family"></a>-family <em class="arg">fontFamily</em></h4>
3215 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set a font family for text.</td><td style="text-align:right;"></td></tr></table>
3217 <p>This setting suggests a font family that ImageMagick should try to use for
3218 rendering text. If the family can be found it is used; if not, a default font
3219 (e.g., "Arial") or a family known to be similar is substituted (e.g.,
3220 "Courier" might be used if "System" is requested but not found). </p>
3222 <p>For other settings that affect fonts, see the options <a href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#stretch">-stretch</a>, <a href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
3224 <div style="margin: auto;">
3225 <h4><a id="features"></a>-features <em class="arg">distance</em></h4>
3228 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">display (cooccurrence matrix) texture measure features for each channel in the image in each of four directions (horizontal, vertical, left and right diagonals) for the specified distance.</td><td style="text-align:right;">[<a href="identify.html">identify</a>]</td></tr></table>
3231 Angular Second Moment
3234 Sum of Squares Variance
3235 Inverse Difference Moment
3242 Information Measure of Correlation 1
3243 Information Measure of Correlation 2
3244 Maximum Correlation Coefficient
3248 <div style="margin: auto;">
3249 <h4><a id="fft"></a>-fft</h4>
3252 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">implements the forward discrete Fourier transform (DFT).</td><td style="text-align:right;"></td></tr></table>
3254 <p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows
3255 users in ImageMagick 6.6.0-9). It transforms an image from the normal
3256 (spatial) domain to the frequency domain. In the frequency domain, an image is
3257 represented as a superposition of complex sinusoidal waves of varying
3258 amplitudes. The image x and y coordinates are the possible frequencies along
3259 the x and y directions, respectively, and the pixel intensity values are
3260 complex numbers that correspond to the sinusoidal wave amplitudes. See for
3261 example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier
3262 Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier
3263 Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier
3266 <p>A single image name is provided as output for this option. However, the
3267 output result will have two components. It is either a two-frame image or two
3268 separate images, depending upon whether the image format specified supports
3269 multi-frame images. The reason that we get a dual output result is because the
3270 frequency domain represents an image using complex numbers, which cannot be
3271 visualized directly. Therefore, the complex values are automagically separated
3272 into a two-component image representation. The first component is the
3273 magnitude of the complex number and the second is the phase of the complex
3274 number. See for example, <a href="http://en.wikipedia.org/wiki/Complex_numbers">Complex Numbers</a>.</p>
3276 <p>The magnitude and phase component images must be specified using image
3277 formats that do not limit the color or compress the image. Thus, MIFF, TIF,
3278 PFM, EXR and PNG are the recommended image formats to use. All of these
3279 formats, except PNG support multi-frame images. So for example,</p>
3281 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert image.png -fft fft_image.miff</span></p>
3282 <p>generates a magnitude image as <code>fft_image.miff[0]</code> and a phase
3283 image as <code>fft_image.miff[1]</code>. Similarly,</p>
3285 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert image.png -fft fft_image.png</span></p>
3286 <p>generates a magnitude image as <code>fft_image-0.png</code> and a phase image
3287 as <code>fft_image-1.png</code>. If you prefer this representation, then you can
3288 force any of the other formats to produce two output images by including <a href="command-line-options.html#adjoin">+adjoin</a> following -fft in the command line.</p>
3290 <p>The input image can be any size, but if not square and even-dimensioned, it
3291 is padded automagically to the larger of the width or height of the input
3292 image and to an even number of pixels. The padding will occur at the bottom
3293 and/or right sides of the input image. The resulting output magnitude and
3294 phase images is square at this size. The kind of padding relies on the <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting.</p>
3296 <p>Both output components will have dynamic ranges that fit within
3297 [0, <em class="QR">QuantumRange</em>], so that HDRI need not be enabled.
3298 Phase values nominally range from 0 to 2*π, but is scaled to span the full
3299 dynamic range. (The first few releases had non-HDRI scaled but HDRI not
3300 scaled). The magnitude image is not scaled and thus generally will contain
3301 very small values. As such, the image normally will appear totally black. In
3302 order to view any detail, the magnitude image typically is enhanced with a log
3303 function into what is usually called the spectrum. A log function is used to
3304 enhance the darker values more in comparison to the lighter values. This can
3305 be done, for example, as follows:</p>
3307 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert fft_image.miff[0] -contrast-stretch 0 \ <br></br>
3308 -evaluate log 1000 fft_image_spectrum.png</span></p>
3309 <p>where either <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a> 0 or <a href="command-line-options.html#auto-level">-auto-level</a> is used to scale the image to full dynamic
3310 range, first. The argument to the <a href="command-line-options.html#evaluate">-evaluate</a> log
3311 typically is specified between 100 and 10,000, depending upon the amount of
3312 detail that one wants to bring out in the spectrum. Larger values produce more
3313 visible detail. Too much detail, however, may hide the important features.</p>
3315 <p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to
3316 use <a href="command-line-options.html#fft">-fft</a>.</p>
3318 <p>Use <a href="command-line-options.html#fft">+fft</a> to produce two output images that are the real
3319 and imaginary components of the complex valued Fourier transform.</p>
3321 <p>However, as the real and imaginary components can contain negative values,
3322 this requires that IM be configured with HDRI enabled. In this case, you must
3323 use either MIFF, TIF, PFM or MPC formats for the real and imaginary component
3324 results, since they are formats that preserve both negative and fractional
3325 values without clipping them or truncating the fractional part. With either
3326 MIFF or TIF, one should add -define quantum:format=32, to allow those image
3327 types to work properly in HDRI mode without clipping.</p>
3329 <p>The real and imaginary component images resulting from <a href="command-line-options.html#fft">+fft</a> are also square, even dimensioned images due to the same
3330 padding that was discussed above for the magnitude and phase component
3333 <p>See the discussion on HDRI implementations of ImageMagick on the page <a href="high-dynamic-range.html">High Dynamic-Range Images</a>. For more
3334 about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages, <a href="http://www.fmwconcepts.com/imagemagick/fourier_transforms/fourier.html">Fred's Fourier Processing With ImageMagick page</a> or this <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
3338 <div style="margin: auto;">
3339 <h4><a id="fill"></a>-fill <em class="arg">color</em></h4>
3342 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">color to use when filling a graphic primitive.</td><td style="text-align:right;"></td></tr></table>
3344 <p>This option accepts a color name, a hex color, or a numerical RGB, RGBA,
3345 HSL, HSLA, CMYK, or CMYKA specification. See <a href="color.html">Color Names</a> for
3346 a description of how to properly specify the color argument.</p>
3348 <p>Enclose the color specification in quotation marks to prevent the "#" or
3349 the parentheses from being interpreted by your shell.</p>
3360 -fill "rgb(255,255,255)"
3363 <p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
3365 <p>To print a complete list of color names, use the <a href="command-line-options.html#list">-list color</a> option.</p>
3367 <div style="margin: auto;">
3368 <h4><a id="filter"></a>-filter <em class="arg">type</em></h4>
3371 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Use this <em class="arg">type</em> of filter when resizing or
3372 distorting an image.</td><td style="text-align:right;"></td></tr></table>
3374 <p>Use this option to affect the resizing operation of an image during
3375 operations such as <a href="command-line-options.html#resize">-resize</a> and <a href="command-line-options.html#distort">-distort</a>. For example you can use a simple resize filter such as:</p>
3380 Triangle Quadratic Mitchell
3383 <p>The <code>Bessel</code> and <code>Sinc</code> filter is also provided (as well
3384 as a faster <code>SincFast</code> equivalent form). However these filters are
3385 generally useless on their own as they are infinite filters that are being
3386 clipped to the filters support size. Their direct use is not recommended
3387 except via expert settings (see below). </p>
3389 <p>Instead these special filter functions are typically windowed by a windowing
3390 function that the <a href="command-line-options.html#filter">-filter</a> setting defines. That is
3391 using these functions will define a 'Windowed' filter, appropriate to the
3392 operator involved. Windowed filters include: </p>
3395 Lanczos Hamming Parzen
3396 Blackman Kaiser Welsh
3397 Hanning Bartlett Bohman
3400 <p>Also one special self-windowing filter is also provided
3401 <code>Lagrange</code>, which will automagically re-adjust its function depending
3402 on the current 'support' or 'lobes' expert settings (see below).</p>
3404 <p>If you do not select a filter with this option, the filter defaults to
3405 <code>Mitchell</code> for a colormapped image, an image with a matte channel, or
3406 if the image is enlarged. Otherwise the filter default to
3407 <code>Lanczos</code>.</p>
3409 <p>To print a complete list of resize filters, use the <a href="command-line-options.html#list">-list
3410 filter</a> option.</p>
3412 <p>You can modify how the filter behaves as it scales your image through the
3413 use of these expert settings (see also <a href="command-line-options.html#define">-define</a> and <a href="command-line-options.html#set">-set</a>):-</p>
3416 <dt>-define filter:blur=<em>factor</em></dt>
3417 <dd>Scale the X axis of the filter (and its window). Use > 1.0 for
3418 blurry or < 1.0 for sharp. This should only be used with Gaussian and
3419 Gaussian-like filters simple filters, or you may not get the expected
3422 <dt>-define filter:support=<em>radius</em></dt>
3423 <dd>Set the filter support radius. Defines how large the filter should be and
3424 thus directly defines how slow the filtered resampling process is. All
3425 filters have a default 'prefered' support size. Some filters like
3426 <code>Lagrange</code> and windowed filters adjust themselves depending on
3427 this value. With simple filters this value either does nothing (but slow
3428 the resampling), or will clip the filter function in a detrimental way.
3431 <dt>-define filter:lobes=<em>count</em></dt>
3432 <dd>Set the number of lobes to use for the Sinc/Bessel filter. This an
3433 alternative way of specifying the 'support' range of the filter, that is
3434 designed to be more suited to windowed filters, especially when used for
3435 image distorts.</dd>
3437 <dt>-define filter:sigma=<em>value</em></dt>
3438 <dd>The 'sigma' value used to define the <code>Gaussian</code> filter. Default
3439 sigma value is '<code>0.5</code>'. It only effects <code>Gaussian</code> but
3440 does not shrink (but may enlarge) the filter's 'support'. It can be used
3441 to generate very small blurs but without the filter 'missing' pixels due
3442 to using a small support setting. A larger value of '<code>0.707</code>'
3443 (a value of '1/sqrt(2)') is another common setting. </dd>
3445 <dt>-define filter:b=<em>b-spline_factor</em></dt>
3446 <dt>-define filter:c=<em>keys_alpha_factor</em></dt>
3447 <dd>Redefine the values used for cubic filters such as <code>Cubic</code>,
3448 <code>Catrom</code>, <code>Mitchel</code>, and <code>Hermite</code>, as well as
3449 the <code>Parzen</code> cubic windowing function. If only one of the values
3450 are defined, the other is set so as to generate a 'Cubic-Keys' filter.
3451 The values meaning was defined by a research paper by
3452 Mitchell-Netravali.</dd>
3454 <dt>-define filter:kaiser-beta=<em>value</em></dt>
3455 <dd>The 'alpha' value used to as part of the Kaiser Windowing function.
3456 Default value is '6.5'. It only effects Kaiser windowing function, and
3457 does not effect any other attributes.</dd>
3459 <dd>Before IM v6.7.6-10, this option was known as "filter:alpha", (an
3460 inheritance from the very old "zoom" program). It was changed to bring the
3461 function in line with more modern academic research usage, and better
3462 assign it be more definitive. </dd>
3464 <dt>-define filter:kaiser-alpha=<em>value</em></dt>
3465 <dd>This value when multiplied by 'PI' is equivelent to "kaiser-beta", and
3466 will override that setting. It only effects Kaiser windowing function,
3467 and does not effect any other attributes. </dd>
3469 <dt>-define filter:filter=<em>filter_function</em></dt>
3470 <dd>Use this function directly as the weighting filter. This will allow
3471 you to directly use a windowing function such as <code>Blackman</code>,
3472 as a resampling filter, rather than as its normal usage as a windowing
3475 <dd>If defined, no windowing function also defined, the window function is set
3476 to <code>Box</code>). Directly specifying <code>Sinc</code> or <code>Jinc</code>
3477 as a filter will also do this. </dd>
3479 <dt>-define filter:window=<em>filter_function</em></dt>
3480 <dd>The IIR (infinite impulse response) filters <code>Sinc</code> and
3481 <code>Jinc</code> are windowed (brought down to zero over the defined
3482 support range) with the given filter. This allows you to specify a filter
3483 function to be used as a windowing function for these IIR filters. </dd>
3485 <dd>Many of the defined filters are actually windowing functions for these IIR
3486 filters. A typical choices is <code>Box</code>, (which effectively turns
3487 off the windowing function). </dd>
3489 <dt>-define filter:win-support=<em>radius</em></dt>
3490 <dd>Scale windowing function to this size instead. This causes the windowing
3491 (or self-windowing Lagrange filter) to act is if the support window is
3492 larger than what is actually supplied to the calling operator. The filter
3493 however is still clipped to the real support size given. If unset this
3494 will equal the normal filter support size. </dd>
3496 <dt>-define filter:verbose=<em>1</em></dt>
3497 <dd>This causes IM to print information on the final internal filter
3498 selection to standard output. This includes a commented header on the
3499 filter settings being used, and data allowing the filter weights to be
3500 easily graphed. </dd>
3502 <dd>Note however that some filters are internally defined in terms of other
3503 filters. The <code>Lanczos</code> filter for example is defined in terms of
3504 a <code>SincFast</code> windowed <code>SincFast</code> filter, while
3505 <code>Mitchell</code> is defined as a general <code>Cubic</code> family filter
3506 with specific 'B' and 'C' settings. </dd>
3510 <p>For example, to get a 8 lobe jinc windowed sinc filter (Genseng filter?):</p>
3512 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert image.png \<br></br>
3513 -filter sinc \<br></br>
3514 -set filter:window=jinc \<br></br>
3515 -set filter:lobes=8 \<br></br>
3516 -resize 150% image.jpg</span></p>
3517 <p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
3519 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert image.png \<br></br>
3520 -set filter:filter=sinc \<br></br>
3521 -set filter:lobes=4 \<br></br>
3522 -resize 150% image.jpg</span></p>
3523 <p>To extract the data for a raw windowing function, combine it with
3524 a '<code>Box</code>' filter. For example the '<code>Welch</code> parabolic
3525 windowing function. </p>
3527 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert null: -define filter:filter=Box \<br></br>
3528 -define filter:window=Welch \<br></br>
3529 -define filter:support=1.0 \<br></br>
3530 -define filter:verbose=1 \<br></br>
3531 -resize 2 null: > window_welch.dat<br></br>
3534 plot "window_welch.dat" with lines</span></p>
3535 <p>Note that the use of expert options is provided for image processing experts
3536 who have studied and understand how resize filters work. Without this
3537 knowledge, and an understanding of the definition of the actual filters
3538 involved, using expert settings are more likely to be detrimental to your image
3542 <div style="margin: auto;">
3543 <h4><a id="flatten"></a>-flatten</h4>
3546 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">This is a simple alias for the <a href="command-line-options.html#layers">-layers</a> method "flatten".</td><td style="text-align:right;"></td></tr></table>
3549 <div style="margin: auto;">
3550 <h4><a id="flip"></a>-flip</h4>
3553 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">create a <em>mirror image</em>.</td><td style="text-align:right;"></td></tr></table>
3555 <p>reflect the scanlines in the vertical direction. The image will be mirrored
3559 <div style="margin: auto;">
3560 <h4><a id="floodfill"></a>-floodfill {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em> <em class="arg">color</em></h4>
3563 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">floodfill the image with color at the specified offset.</td><td style="text-align:right;"></td></tr></table>
3565 <p>Flood fill starts from the given 'seed point' which is not gravity effected.
3566 Any color that matches within <a href="command-line-options.html#fuzz">-fuzz</a> color distance of the
3567 given <em class="arg">color</em> argument, connected to that 'seed point'
3568 will be replaced with the current <a href="command-line-options.html#fill">-fill</a> color. </p>
3570 <p>Note that if the pixel at the 'seed point' does not itself match the given
3571 <em class="arg">color</em> (according to <a href="command-line-options.html#fuzz">-fuzz</a>), then no
3572 action will be taken. </p>
3574 <p>This operator works more like the <a href="command-line-options.html#opaque">-opaque</a> option, than
3575 a more general flood fill that reads the matching color directly at the 'seed
3576 point'. For this form of flood fill, look at <a href="command-line-options.html#draw">-draw</a> and
3577 its 'color floodfill' drawing method. </p>
3580 <div style="margin: auto;">
3581 <h4><a id="flop"></a>-flop</h4>
3584 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">create a <em>mirror image</em>.</td><td style="text-align:right;"></td></tr></table>
3586 <p>Reflect the scanlines in the horizontal direction, just like the image in
3587 a vertical mirror. </p>
3590 <div style="margin: auto;">
3591 <h4><a id="font"></a>-font <em class="arg">name</em></h4>
3594 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">set the font to use when annotating images with text, or creating labels.</td><td style="text-align:right;"></td></tr></table>
3596 <p>To print a complete list of fonts, use the <a href="command-line-options.html#list">-list font</a>
3597 option (for versions prior to 6.3.6, use 'type' instead of 'font').</p>
3599 <p>In addition to the fonts specified by the above pre-defined list, you can
3600 also specify a font from a specific source. For example <code>Arial.ttf</code>
3601 is a TrueType font file, <code>ps:helvetica</code> is PostScript font, and
3602 <code>x:fixed</code> is X11 font.</p>
3604 <p>For other settings that affect fonts, see the options <a href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#stretch">-stretch</a>, <a href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
3607 <div style="margin: auto;">
3608 <h4><a id="foreground"></a>-foreground <em class="arg">color</em></h4>
3611 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Define the foreground color for menus.</td><td style="text-align:right;">[<a href="display.html">display</a>]</td></tr></table>
3613 <p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
3615 <p>The default foreground color is black.</p>
3617 <div style="margin: auto;">
3618 <h4><a id="format"></a>-format <em class="arg">type</em></h4>
3621 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">the image format type.</td><td style="text-align:right;"></td></tr></table>
3623 <p>When used with the <code>mogrify</code> utility, this option converts any
3624 image to the image <a href="formats.html">format</a> you specify.
3625 For a list of image format types supported by ImageMagick, use <a href="command-line-options.html#list">-list format</a>.</p>
3627 <p>By default the file is written to its original name. However, if the
3628 filename extension matches a supported format, the extension is replaced with
3629 the image format type specified with <a href="command-line-options.html#format">-format</a>. For
3630 example, if you specify <em class="arg">tiff</em> as the format type and the
3631 input image filename is <em class="arg">image.gif</em>, the output image
3632 filename becomes <em class="arg">image.tiff</em>.</p>
3634 <div style="margin: auto;">
3635 <h4><a id="format_identify_"></a>-format <em class="arg">string</em></h4>
3638 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">output formatted image characteristics.</td><td style="text-align:right;">[<a href="identify.html">identify</a>]</td></tr></table>
3640 <p>See <a href="escape.html">Format and Print Image
3641 Properties</a> for an explanation on how to specify the argument to this
3644 <div style="margin: auto;">
3645 <h4><a id="frame"></a>-frame <em class="arg">geometry</em></h4>
3648 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Surround the image with a border or beveled frame.</td><td style="text-align:right;"></td></tr></table>
3650 <p>The color of the border is specified with the <a href="command-line-options.html#mattecolor">-mattecolor</a> command line option. </p>
3652 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <em class="arg">size</em> portion of the <em class="arg">geometry</em> argument indicates the amount of extra width and
3653 height that is added to the dimensions of the image. If no offsets are given
3654 in the <em class="arg">geometry</em> argument, then the border added is
3655 a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that
3656 the width and height of the border is partitioned to form an outer bevel of
3657 thickness <em>x</em> pixels and an inner bevel of thickness
3658 <em>y</em> pixels. Negative offsets make no sense as frame arguments.
3661 <p>The <a href="command-line-options.html#frame">-frame</a> option is affected by the current <a href="command-line-options.html#compose">-compose</a> setting and assumes that this is using the default
3662 '<code>Over</code>' composition method. It generates an image of the appropriate
3663 size with the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting, and then
3664 draws the frame of four distinct colors close to the current <a href="command-line-options.html#mattecolor">-mattecolor</a>. The original image is then overlaid onto
3665 center of this image. This means that with the default compose method of
3666 '<code>Over</code>' any transparent parts may be replaced by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
3668 <p>The image composition is not
3669 affected by the <a href="command-line-options.html#gravity">-gravity</a> option.</p>
3672 <div style="margin: auto;">
3673 <h4><a id="frame_import_"></a>-frame</h4>
3676 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">include the X window frame in the imported image.</td><td style="text-align:right;">[<a href="import.html">import</a>]</td></tr></table>
3678 <div style="margin: auto;">
3679 <h4><a id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4>
3682 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Apply a function to channel values.</td><td style="text-align:right;"></td></tr></table>
3684 <p>This operator performs calculations based on the given arguments to modify
3685 each of the color values for each previously set <a href="command-line-options.html#channel">-channel</a> in the image. See <a href="command-line-options.html#evaluate">-evaluate</a> for details concerning how the results of the
3686 calculations are handled.</p>
3688 <p>This is can be considered a multi-argument version of the <a href="command-line-options.html#evaluate">-evaluate</a> operator. (Added in
3689 ImageMagick 6.4.8−8.)</p>
3691 <p>Here, <em class="arg">parameters</em> is a comma-separated list of
3692 numerical values. The number of values varies depending on which <em class="arg">function</em> is selected. Choose the <em class="arg">function</em> from:</p>
3701 <p>To print a complete list of <a href="command-line-options.html#function">-function</a> operators,
3702 use <a href="command-line-options.html#list">-list function</a>. Descriptions follow.</p>
3705 <dt><code>Polynomial</code></dt>
3708 <p>The <code>Polynomial</code> function takes an arbitrary number of parameters,
3709 these being the coefficients of a polynomial, in decreasing order of degree.
3710 That is, entering</p>
3712 <div style="text-align: center">
3713 -function Polynomial <em>a</em><sub><em>n</em></sub>,<em>a</em><sub><em>n</em>-1</sub>,...<em>a</em><sub>1</sub>,<em>a</em><sub>0</sub>
3716 <p>will invoke a polynomial function given by</p>
3718 <div style="text-align: center">
3719 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> +
3720 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> +
3721 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>,
3724 <p>where <b><em>u</em></b> is pixel's original normalized channel value.</p>
3726 <p>The <code>Polynomial</code> function can be used in place of <code>Set</code>
3727 (the <em>constant</em> polynomial) and <code>Add</code>, <code>Divide</code>,
3728 <code>Multiply</code>, and <code>Subtract</code> (some <em>linear</em>
3729 polynomials) of the <a href="command-line-options.html#evaluate">-evaluate</a> operator. The <a href="command-line-options.html#level">-level</a> operator also affects channels linearly. Some
3730 correspondences follow.</p>
3733 <col width="35%"></col>
3734 <col width="35%"></col>
3735 <col width="30%"></col>
3737 <td>-evaluate Set <em class="arg">value</em> </td>
3738 <td>-function Polynomial <em class="arg">value</em></td>
3739 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td>
3742 <td>-evaluate Add <em class="arg">value</em> </td>
3743 <td>-function Polynomial 1,<em class="arg">value</em></td>
3746 <td>-evaluate Subtract <em class="arg">value</em> </td>
3747 <td>-function Polynomial 1,−<em class="arg">value</em></td>
3750 <td>-evaluate Multiply <em class="arg">value</em> </td>
3751 <td>-function Polynomial <em class="arg">value</em>,0</td>
3754 <td>+level black% x white%</td>
3755 <td>-function Polynomial A,B</td>
3756 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
3760 <p>The <code>Polynomial</code> function gives great versatility, since
3761 polynomials can be used to fit any continuous curve to any degree of accuracy
3766 <dt><code>Sinusoid</code></dt>
3768 <p>The <code>Sinusoid</code> function can be used to vary the channel values
3769 sinusoidally by setting frequency, phase shift, amplitude, and a bias. These
3770 values are given as one to four parameters, as follows,</p>
3772 <div style="text-align: center">
3773 -function <code>Sinusoid</code> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]]
3776 <p>where <em>phase</em> is in degrees. (The domain [0,1] of the function
3777 corresponds to 0 through <em class="arg">freq</em>×360 degrees.)
3778 The result is that if a pixel's normalized channel value is originally
3779 <b><em>u</em></b>, its resulting normalized value is given by </p>
3781 <div style="text-align: center">
3782 <em class="arg">amp</em> * sin(2*π* (<em class="arg">freq</em> * <b><em>u</em></b> + <em class="arg">phase</em> / 360)) + <em class="arg">bias</em>
3785 <p> For example, the following generates a curve that starts and ends at 0.9
3786 (when <b><em>u</em></b>=0 and 1, resp.), oscillating three times between
3787 .7−.2=.5 and .7+.2=.9. </p>
3790 -function Sinusoid 3,-90,.2,.7
3793 <p>The default values of <em class="arg">amp</em> and <em class="arg">bias</em> are both .5. The default for <em class="arg">phase</em>
3796 <p>The <code>Sinusoid</code> function generalizes <code>Sin</code> and
3797 <code>Cos</code> of the <a href="command-line-options.html#evaluate">-evaluate</a> operator by allowing
3798 varying amplitude, phase and bias. The correspondence is as follows.</p>
3802 <td>-evaluate Sin <em class="arg">freq</em> </td>
3803 <td>-function Sinusoid <em class="arg">freq</em>,0 </td>
3806 <td>-evaluate Cos <em class="arg">freq</em> </td>
3807 <td>-function Sinusoid <em class="arg">freq</em>,90 </td>
3812 <dt><code>ArcSin</code></dt>
3814 <p>The <code>ArcSin</code> function generates the inverse curve of a Sinusoid,
3815 and can be used to generate cylindrical distortion and displacement maps.
3816 The curve can be adjusted relative to both the input values and output range
3819 <p style="text-align: center">
3820 -function <code>ArcSin</code> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3823 <p>with all values given in terms of normalized color values (0.0 for black,
3824 1.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
3825 for bout input (<em class="arg">width</em>), and output (<em class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
3827 <p style="text-align: center">
3828 <em class="arg">range</em>/π * asin( 2/<em class="arg">width</em> * ( <b><em>u</em></b> - <em class="arg">center</em> ) ) + <em class="arg">bias</em>
3833 <dt><code>ArcTan</code></dt>
3835 <p>The <code>ArcTan</code> function generates a curve that smooth crosses from
3836 limit values at infinities, though a center using the given slope value.
3837 All these values can be adjusted via the arguments.</p>
3839 <p style="text-align: center">
3840 -function <code>ArcTan</code> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3843 <p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3846 <p style="text-align: center">
3847 <em class="arg">range</em>/π * atan( <em class="arg">slope</em>*π * ( <b><em>u</em></b> - <em class="arg">center</em> ) ) + <em class="arg">bias</em>
3855 <div style="margin: auto;">
3856 <h4><a id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4>
3859 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Colors within this <em class="arg">distance</em> are considered equal.</td><td style="text-align:right;"></td></tr></table>
3861 <p>A number of algorithms search for a target color. By default the color must
3862 be exact. Use this option to match colors that are close to the target color
3863 in RGB space. For example, if you want to automagically trim the edges of an
3864 image with <a href="command-line-options.html#trim">-trim</a> but the image was scanned and the target
3865 background color may differ by a small amount. This option can account for
3866 these differences.</p>
3868 <p>The <em class="arg">distance</em> can be in absolute intensity units or, by
3869 appending <code>%</code> as a percentage of the maximum possible intensity (255,
3870 65535, or 4294967295).</p>
3873 <div style="margin: auto;">
3874 <h4><a id="fx"></a>-fx <em class="arg">expression</em></h4>
3877 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">apply a mathematical expression to an image or image channels.</td><td style="text-align:right;"></td></tr></table>
3879 <p>If the first character of <em class="arg">expression</em> is <code>@</code>,
3880 the expression is read from a file titled by the remaining characters in the
3883 <p>See <a href="fx.html">FX,
3884 The Special Effects Image Operator</a> for a detailed discussion of this
3888 <div style="margin: auto;">
3889 <h4><a id="gamma"></a>-gamma <em class="arg">value</em></h4>
3892 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">level of gamma correction.</td><td style="text-align:right;"></td></tr></table>
3894 <p>The same color image displayed on two different workstations may look
3895 different due to differences in the display monitor. Use gamma correction to
3896 adjust for this color difference. Reasonable values extend from
3897 <code>0.8</code> to <code>2.3</code>. Gamma less than 1.0 darkens the image and
3898 gamma greater than 1.0 lightens it. Large adjustments to image gamma may
3899 result in the loss of some image information if the pixel quantum size is only
3900 eight bits (quantum range 0 to 255).</p>
3902 <p>Gamma adjusts the image's channel values pixel-by-pixel according to
3903 a power law, namely, pow(pixel,1/gamma) or pixel^(1/gamma), where pixel is the
3904 normalized or 0 to 1 color value. For example, using a value of gamma=2 is the
3905 same as taking the square root of the image.</p>
3907 <p>You can apply separate gamma values to the red, green, and blue channels of
3908 the image with a gamma value list delimited with commas (e.g.,
3909 <code>1.7,2.3,1.2</code>).</p>
3911 <p>Use <a href="command-line-options.html#gamma">+gamma <em class="arg">value</em></a> to set the
3912 image gamma level without actually adjusting the image pixels. This option
3913 is useful if the image is of a known gamma but not set as an image attribute
3914 (e.g. PNG images). Write the "file gamma" which is the reciprocal of the
3915 display gamma; e.g., if your image is sRGB and you want to write a PNG gAMA
3917 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert input.png +gamma .45455 output.png</span></p><p>(0.45455 is 1/2.2)</p>
3919 <p>Note that gamma adjustments are also available via the <a href="command-line-options.html#level">-level</a> operator.</p>
3921 <div style="margin: auto;">
3922 <h4><a id="gaussian-blur"></a>-gaussian-blur <em class="arg">radius</em><br></br>-gaussian-blur <em class="arg">radius</em>x<em class="arg">sigma</em>+<em class="arg">bias</em></h4>
3925 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Blur the image with a Gaussian operator.</td><td style="text-align:right;"></td></tr></table>
3927 <p>Convolve the image with a Gaussian or normal distribution using the given
3928 <em class="arg">Sigma</em> value. The formula is:</p>
3930 <div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"></img>
3933 <p>The <em class="arg">Sigma</em> value is the important argument, and
3934 determines the actual amount of blurring that will take place. </p>
3936 <p>The <em class="arg">Radius</em> is only used to determine the size of the
3937 array which will hold the calculated Gaussian distribution. It should be an
3938 integer. If not given, or set to zero, IM will calculate the largest possible
3939 radius that will provide meaningful results for the Gaussian distribution.
3942 <p>The larger the <em class="arg">Radius</em> the radius the slower the
3943 operation is. However too small a <em class="arg">Radius</em>, and sever
3944 aliasing effects may result. As a guideline, <em class="arg">Radius</em>
3945 should be at least twice the <em class="arg">Sigma</em> value, though three
3946 times will produce a more accurate result. </p>
3948 <p>This differs from the faster <a href="command-line-options.html#blur">-blur</a> operator in that a
3949 full 2-dimensional convolution is used to generate the weighted average of the
3950 neighboring pixels. </p>
3952 <p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
3953 pixels which are outside the image proper are blurred into the final result.
3957 <div style="margin: auto;">
3958 <h4><a id="geometry"></a>-geometry <em class="arg">geometry</em></h4>
3961 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the preferred size and location of the image.</td><td style="text-align:right;"></td></tr></table>
3963 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3965 <div style="margin: auto;">
3966 <h4><a id="gravity"></a>-gravity <em class="arg">type</em></h4>
3969 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Sets the current gravity suggestion for various other settings and options.</td><td style="text-align:right;"></td></tr></table>
3971 <p>Choices include: <code>NorthWest</code>, <code>North</code>,
3972 <code>NorthEast</code>, <code>West</code>, <code>Center</code>, <code>East</code>,
3973 <code>SouthWest</code>, <code>South</code>, <code>SouthEast</code>. Use <a href="command-line-options.html#list">-list gravity</a> to get a complete list of <a href="command-line-options.html#gravity">-gravity</a> settings available in your ImageMagick
3976 <p>The direction you choose specifies where to position text or subimages. For
3977 example, a gravity of <code>Center</code> forces the text to be centered within
3978 the image. By default, the image gravity is <code>NorthWest</code>. See <a href="command-line-options.html#draw">-draw</a> for more details about graphic primitives. Only the
3979 text primitive of <a href="command-line-options.html#draw">-draw</a> is affected by the <a href="command-line-options.html#gravity">-gravity</a> option.</p>
3981 <p>The <a href="command-line-options.html#gravity">-gravity</a> option is also used in concert with the
3982 <a href="command-line-options.html#geometry">-geometry</a> setting and other settings or options that
3983 take <em class="arg">geometry</em> as an argument, such as the <a href="command-line-options.html#crop">-crop</a> option. </p>
3985 <p>If a <a href="command-line-options.html#gravity">-gravity</a> setting occurs before another option
3986 or setting having a <em class="arg">geometry</em> argument that specifies an
3987 offset, the offset is usually applied to the point within the image suggested
3988 by the <a href="command-line-options.html#gravity">-gravity</a> argument. Thus, in the following
3989 command, for example, suppose the file <code>image.png</code> has dimensions
3990 200x100. The offset specified by the argument to <a href="command-line-options.html#region">-region</a>
3991 is (−40,+20). The argument to <a href="command-line-options.html#gravity">-gravity</a> is
3992 <code>Center</code>, which suggests the midpoint of the image, at the point
3993 (100,50). The offset (−40,20) is applied to that point, giving
3994 (100−40,50+20)=(60,70), so the specified 10x10 region is located at
3995 that point. (In addition, the <a href="command-line-options.html#gravity">-gravity</a> affects the
3996 region itself, which is <em>centered</em> at the pixel
3997 coordinate (60,70). (See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.)</p>
3999 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert image.png -gravity Center -region 10x10-40+20 \ <br></br> -negate output.png</span></p>
4000 <p>When used as an option to <a href="composite.html">composite</a>, <a href="command-line-options.html#gravity">-gravity</a> gives the direction that the image gravitates
4001 within the composite.</p>
4003 <p>When used as an option to <a href="montage.html">montage</a>, <a href="command-line-options.html#gravity">-gravity</a> gives the direction that an image gravitates
4004 within a tile. The default gravity is <code>Center</code> for this purpose.</p>
4007 <div style="margin: auto;">
4008 <h4><a id="grayscale"></a>-grayscale <em class="arg">method</em></h4>
4011 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">convert image to grayscale.</td><td style="text-align:right;"></td></tr></table>
4013 <p>This will use one of the <a href="command-line-options.html#intensity">-intensity</a> methods to
4014 convert the given image into a linear-grayscale image. </p>
4016 <p>For example, to convert an image to (linear) Rec709Luminance grayscale, type:</p>
4018 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert in.png -grayscale Rec709Luminance out.png</span></p>
4019 <p>which is equivalent to:</p>
4021 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert in.png -colorspace gray out.png</span></p>
4022 <p>Similarly, to convert an image to (non-linear) Rec709Luma grayscale, type:</p>
4024 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert in.png -grayscale Rec709Luma out.png</span></p>
4025 <p>which is equivalent to:</p>
4027 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert in.png -set colorspace RGB -colorspace gray out.png</span></p>
4028 <p>Note that a 'colorspace' intensity method will produce the same result
4029 regardless of the current colorpsace of the image. But a 'mathematical'
4030 intensity method will depend on the current colorspace the image is currently
4033 <p>While this operation uses an <a href="command-line-options.html#intensity">-intensity</a> method,
4034 it does not use or set the <a href="command-line-options.html#intensity">-intensity</a> setting, so
4035 will not effect other operations that may use that setting.</p>
4038 <div style="margin: auto;">
4039 <h4><a id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4>
4042 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">green chromaticity primary point.</td><td style="text-align:right;"></td></tr></table>
4045 <div style="margin: auto;">
4046 <h4><a id="hald-clut"></a>-hald-clut</h4>
4049 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">apply a Hald color lookup table to the image.</td><td style="text-align:right;"></td></tr></table>
4051 <p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
4052 dimensions. Create it with the <code>HALD:</code> prefix (e.g. HALD:8). You
4053 can apply any color transformation to the Hald image and then use this option
4054 to apply the transform to the image. </p>
4056 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert image.png hald.png -hald-clut transform.png</span></p>
4057 <p>This option provides a convenient method for you to use Gimp or Photoshop
4058 to make color corrections to the Hald CLUT image and subsequently apply them
4059 to multiple images using an ImageMagick script. </p>
4061 <p>Note that the representation is only of the normal RGB color space and that
4062 the whole color value triplet is used for the interpolated lookup of the
4063 represented Hald color cube image. Because of this the operation is not <a href="command-line-options.html#channel">-channel</a> setting effected, nor can it adjust or modify an
4064 images transparency or alpha/matte channel.</p>
4066 <p>See also <a href="command-line-options.html#clut">-clut</a> which provides color value replacement
4067 of the individual color channels, usually involving a simpler gray-scale
4068 image. E.g: gray-scale to color replacement, or modification by a histogram
4072 <div style="margin: auto;">
4073 <h4><a id="help"></a>-help</h4>
4076 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">print usage instructions.</td><td style="text-align:right;"></td></tr></table>
4078 <div style="margin: auto;">
4079 <h4><a id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4>
4082 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">when comparing images, emphasize pixel differences with this color.</td><td style="text-align:right;"></td></tr></table>
4084 <div style="margin: auto;">
4085 <h4><a id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4>
4088 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">specify the icon geometry.</td><td style="text-align:right;"></td></tr></table>
4090 <p>Offsets, if present in the geometry specification, are handled in the same
4091 manner as the <a href="command-line-options.html#geometry">-geometry</a> option, using X11 style to
4092 handle negative offsets.</p>
4094 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4096 <div style="margin: auto;">
4097 <h4><a id="iconic"></a>-iconic</h4>
4100 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">start in icon mode in X Windows</td><td style="text-align:right;">[<a href="animate.html">animate</a>, <a href="display.html">display</a>]</td></tr></table>
4102 <div style="margin: auto;">
4103 <h4><a id="identify"></a>-identify</h4>
4106 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">identify the format and characteristics of the image.</td><td style="text-align:right;"></td></tr></table>
4108 <p>This information is printed: image scene number; image name; image size;
4109 the image class (<em class="arg">DirectClass</em> or <em class="arg">PseudoClass</em>); the total number of unique colors; and the
4110 number of seconds to read and transform the image. Refer to <a href="miff.html">MIFF</a> for
4111 a description of the image class.</p>
4113 <p>If <a href="command-line-options.html#colors">-colors</a> is also specified, the total unique colors
4114 in the image and color reduction error values are printed. Refer to <a href="quantize.html">color
4115 reduction algorithm</a> for a description of these values.</p>
4117 <p>If <a href="command-line-options.html#verbose">-verbose</a> precedes this option, copious
4118 amounts of image properties are displayed including image statistics, profiles,
4119 image histogram, and others.</p>
4121 <div style="margin: auto;">
4122 <h4><a id="ift"></a>-ift</h4>
4125 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">implements the inverse discrete Fourier transform (DFT).</td><td style="text-align:right;"></td></tr></table>
4127 <p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows
4128 users in ImageMagick 6.6.0-9). It transforms a pair of magnitude and phase
4129 images from the frequency domain to a single image in the normal or spatial
4130 domain. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier Transform</a>,
4131 <a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier Transform</a> and
4132 <a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier Transform</a>.</p>
4134 <p>For example, depending upon the image format used to store the result of
4135 the <a href="command-line-options.html#fft">-fft</a>, one would use either</p>
4137 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert fft_image.miff -ift fft_image_ift.png</span></p>
4140 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert fft_image-0.png fft_image-1.png -ift fft_image_ift.png</span></p>
4142 <p>The resulting image may need to be cropped due to padding introduced when
4143 the original image, prior to the <a href="command-line-options.html#fft">-fft</a> or <a href="command-line-options.html#fft">+fft</a>, was not square or even dimensioned. Any padding is at
4144 the right and/or bottom sides of the image.</p>
4146 <p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to
4147 use <a href="command-line-options.html#ift">-ift</a>.</p>
4149 <p>Use <a href="command-line-options.html#ift">+ift</a> (with HDRI enabled) to transform a pair of real
4150 and imaginary images from the frequency domain to a single image in the normal
4151 (spatial) domain.</p>
4153 <div style="margin: auto;">
4154 <h4><a id="immutable"></a>-immutable</h4>
4157 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">make image immutable.</td><td style="text-align:right;"></td></tr></table>
4159 <div style="margin: auto;">
4160 <h4><a id="implode"></a>-implode <em class="arg">factor</em></h4>
4163 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">implode image pixels about the center.</td><td style="text-align:right;"></td></tr></table>
4165 <div style="margin: auto;">
4166 <h4><a id="insert"></a>-insert <em class="arg">index</em></h4>
4169 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">insert the last image into the image sequence.</td><td style="text-align:right;"></td></tr></table>
4171 <p>This option takes last image in the current image sequence and inserts it
4172 at the given index. If a negative index is used, the insert position is
4173 calculated before the last image is removed from the sequence. As such
4174 <code>-insert -1</code> will result in no change to the image sequence.</p>
4176 <p>The <code>+insert</code> option is equivalent to <code>-insert -1</code>. In
4177 other words, insert the last image, at the end of the current image sequence.
4178 Consequently this has no effect on the image sequence order.</p>
4180 <div style="margin: auto;">
4181 <h4><a id="intensity"></a>-intensity <em class="arg">method</em></h4>
4184 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">method to generate intensity value from pixel.</td><td style="text-align:right;"></td></tr></table>
4186 <p>ImageMagick provides a number of methods used in situations where an
4187 operatory needs to determine a single grayscale value for some purpose, from
4188 an image with red, green, and blue pixel components. Typically the linear
4189 <code>Rec709Luminance</code> formula is used, which is the same formula used when
4190 converting images to <code>-colorspace gray</code>. </p>
4192 <p>The following formulas are currently provided, and will first convert
4193 the pixel values to linear-RGB or non-linear sRGB colorspace before
4194 being applied to calulate the final greyscale value. </p>
4197 Rec601Luma 0.298839R' + 0.586811G'+ 0.114350B'
4198 Rec601Luminance 0.298839R + 0.586811G + 0.114350B
4199 Rec709Luma 0.212656R' + 0.715158G' + 0.072186B'
4200 Rec709Luminance 0.212656R + 0.715158G + 0.072186B
4201 Brightness max(R', G', B')
4202 Lightness (min(R', G', B') + max(R', G', B')) / 2.0
4204 <p>Note that the above R,G,B values is the image's linear-RGB values, while
4205 R',G',B' are sRGB non-linear values. </p>
4207 <p>These intensity methods are mathematical in nature and will use the
4208 current value in the images respective R,G,B channel regardless of
4209 what that is, or what colorspace the image is currently using.</p>
4212 Average (R + G + B) / 3.0
4213 MS (R^2 + G^2 + B^2) / 3.0
4214 RMS sqrt( (R^2 + G^2 + B^2) / 3.0 )
4217 <p>These methods are often used for other purposes, such as generating a
4218 grayscale difference image between two color images (using <a href="command-line-options.html#compose">-compose</a> '<code>Difference</code>' composition. </p>
4220 <p> For example The 'MS' (Mean Squared) setting is good for minimizing color
4221 error comparisions. While... The method 'RMS' (Root Mean Squared) for
4222 example is appropriate for calculating color vector distance, from a color
4223 difference image. This is equivelent to the color only component of the <a href="command-line-options.html#fuzz">-fuzz</a> factor color compare setting. </p>
4225 <p>See also <a href="command-line-options.html#grayscale">-grayscale</a> which applies one of the above
4226 grayscaling formula directly to an image without setting the <a href="command-line-options.html#intensity">-intensity</a> setting.</p>
4228 <p>The <a href="command-line-options.html#colorspace">-colorspace gray</a> image conversion also uses
4229 the current intensity setting, but will always convert the image to the
4230 appropriate sRGB or linear-RGB colorspace before appling the above
4233 <p>To print a complete list of posible pixel intensity setting methods, use <a href="command-line-options.html#list">-list intensity</a>.</p>
4235 <p>Operators affected by the <a href="command-line-options.html#intensity">-intensity</a> setting include:</p>
4241 -clut (when mapping greyscale CLUT image to alpha channel if set by -channels)
4242 -colors for gray colorspace
4243 -compose {LightenIntensity, DarkenIntensity, CopyOpacity, CopyBlack}
4245 -distort {ErodeIntensity, DilateIntensity}
4255 <div style="margin: auto;">
4256 <h4><a id="intent"></a>-intent <em class="arg">type</em></h4>
4259 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">use this type of rendering intent when managing the image color.</td><td style="text-align:right;"></td></tr></table>
4261 <p>Use this option to affect the color management operation of an image (see
4262 <a href="command-line-options.html#profile">-profile</a>). Choose from these intents: <code>Absolute,
4263 Perceptual, Relative, Saturation</code>.</p>
4265 <p>The default intent is Perceptual for the sRGB colorspace and undefined for the RGB and gray colorspaces.</p>
4267 <p>To print a complete list of rendering intents, use <a href="command-line-options.html#list">-list intent</a>.</p>
4269 <div style="margin: auto;">
4270 <h4><a id="interlace"></a>-interlace <em class="arg">type</em></h4>
4273 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">the type of interlacing scheme.</td><td style="text-align:right;"></td></tr></table>
4287 <p>This option is used to specify the type of interlacing scheme for raw image
4288 formats such as <code>RGB</code> or <code>YUV</code>.</p>
4290 <p><code>None</code> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
4292 <p><code>Line</code> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
4294 <p><code>Plane</code> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
4296 <p><code>Partition</code> is like plane except the different planes are saved to
4297 individual files (e.g. image.R, image.G, and image.B).</p>
4299 <p>Use <code>Line</code> or <code>Plane</code> to create an <code>interlaced
4300 PNG</code> or <code>GIF</code> or <code>progressive JPEG</code> image.</p>
4302 <p>To print a complete list of interlacing schemes, use <a href="command-line-options.html#list">-list
4305 <div style="margin: auto;">
4306 <h4><a id="interpolate"></a>-interpolate <em class="arg">type</em></h4>
4309 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the pixel color interpolation method to use when looking up a color based on a floating point or real value.</td><td style="text-align:right;"></td></tr></table>
4311 <p>When looking up the color of a pixel using a non-integer floating point
4312 value, you typically fall in between the pixel colors defined by the source
4313 image. This setting determines how the color is determined from the colors of
4314 the pixels surrounding that point. That is how to determine the color of a
4315 point that falls between two, or even four different colored pixels. </p>
4318 integer The color of the top-left pixel (floor function)
4319 nearest-neighbor The nearest pixel to the lookup point (rounded function)
4320 average The average color of the surrounding four pixels
4321 bilinear A double linear interpolation of pixels (the default)
4322 mesh Divide area into two flat triangular interpolations
4323 bicubic Fitted bicubic-spines of surrounding 16 pixels
4324 spline Direct spline curves (colors are blurred)
4325 filter Use resize <a href="command-line-options.html#filter">-filter</a> settings
4328 <p>This most important for distortion operators such as <a href="command-line-options.html#distort">-distort</a>, <a href="command-line-options.html#implode">-implode</a>, <a href="command-line-options.html#transform">-transform</a> and <a href="command-line-options.html#fx">-fx</a>. </p>
4330 <p>To print a complete list of interpolation methods, use <a href="command-line-options.html#list">-list interpolate</a>.</p>
4332 <p>See also <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a>, for control of the
4333 lookup for positions outside the boundaries of the image. </p>
4336 <div style="margin: auto;">
4337 <h4><a id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4>
4340 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">the space between two text lines.</td><td style="text-align:right;"></td></tr></table>
4342 <div style="margin: auto;">
4343 <h4><a id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4>
4346 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">the space between two words.</td><td style="text-align:right;"></td></tr></table>
4348 <div style="margin: auto;">
4349 <h4><a id="kerning"></a>-kerning <em class="arg">value</em></h4>
4352 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">the space between two letters.</td><td style="text-align:right;"></td></tr></table>
4354 <div style="margin: auto;">
4355 <h4><a id="label"></a>-label <em class="arg">name</em></h4>
4358 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">assign a label to an image.</td><td style="text-align:right;"></td></tr></table>
4360 <p>Use this option to assign a specific label to the image, as it is read in
4361 or created. You can use the <a href="command-line-options.html#set">-set</a> operation to re-assign
4362 a the labels of images already read in. Image formats such as TIFF, PNG,
4363 MIFF, supports saving the label information with the image.</p>
4365 <p>When saving an image to a <em class="arg">PostScript</em> file, any label
4366 assigned to an image is used as a header string to print above the postscript
4369 <p>You can include the image filename, type, width, height, or other image
4370 attribute by embedding special format character. See <a href="escape.html">Format and Print Image
4371 Properties</a> for details of the percent escape codes.</p>
4376 -label "%m:%f %wx%h" bird.miff
4379 <p>assigns an image label of <code>MIFF:bird.miff 512x480</code> to the
4380 "<code>bird.miff</code>" image and whose width is 512 and height is 480, as it
4381 is read in. If a <a href="command-line-options.html#label">+label</a> option was used instead, any
4382 existing label present in the image would be used. You can remove all labels
4383 from an image by assigning the empty string. </p>
4385 <p>A label is not drawn on the image, but is embedded in the image datastream
4386 via <em>Label</em> tag or similar mechanism. If you want the label to be
4387 visible on the image itself, use the <a href="command-line-options.html#draw">-draw</a> option, or
4388 during the final processing in the creation of an image montage.</p>
4390 <p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image label is read from a file titled by the
4391 remaining characters in the string. Labels in a file are literal, no embedded
4392 formatting characters are recognized.</p>
4395 <div style="margin: auto;">
4396 <h4><a id="lat"></a>-lat <em class="arg">width</em><br></br>-lat <em class="arg">width</em>x<em class="arg">height</em>{<em class="arg">+-</em>}<em class="arg">offset</em>{<em class="arg">%</em>}</h4>
4399 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">perform local adaptive threshold.</td><td style="text-align:right;"></td></tr></table>
4401 <p>Adaptively threshold each pixel based on the value of pixels in a
4402 surrounding window. If the current pixel is lighter than this average plus
4403 the optional <code>offset</code>, then it is made white, otherwise it is made
4404 black. Small variations in pixel values such as found in scanned documents
4405 can be ignored if offset is positive. A negative offset will make it more
4406 sensitive to those small variations. </p>
4408 <p>This is commonly used to threshold images with an uneven background. It is
4409 based on the assumption that average color of the small window is the
4410 the local background color, from which to separate the foreground color. </p>
4413 <div style="margin: auto;">
4414 <h4><a id="layers"></a>-layers <em class="arg">method</em></h4>
4417 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">handle multiple images forming a set of image layers or animation frames.</td><td style="text-align:right;"></td></tr></table>
4419 <p>Perform various image operation methods to a ordered sequence of images
4420 which may represent either a set of overlaid 'image layers', a GIF disposal
4421 animation, or a fully-'coalesced' animation sequence. </p>
4426 <th align="left" style="width: 8%">Method</th>
4427 <th align="left">Description</th>
4431 <td valign="top">compare-any</td>
4432 <td valign="top">Crop the second and later frames to the smallest rectangle
4433 that contains all the differences between the two images. No GIF <a href="command-line-options.html#dispose">-dispose</a> methods are taken into account. </td>
4436 <tr><td></td><td>This exactly the same as the <a href="command-line-options.html#deconstruct">-deconstruct</a> operator, and does not preserve animations normal
4437 working, especially when animation used layer disposal methods such as
4438 '<code>Previous</code>' or '<code>Background</code>'. </td>
4442 <td valign="top">compare-clear</td>
4443 <td valign="top">As '<code>compare-any</code>' but crop to the bounds of any
4444 opaque pixels which become transparent in the second frame. That is the
4445 smallest image needed to mask or erase pixels for the next frame. </td>
4449 <td valign="top">compare-overlay</td>
4450 <td valign="top">As '<code>compare-any</code>' but crop to pixels that add
4451 extra color to the next image, as a result of overlaying color pixels.
4452 That is the smallest single overlaid image to add or change colors. </td>
4455 <tr><td></td><td>This can be used with the <a href="command-line-options.html#compose">-compose</a> alpha
4456 composition method '<code>change-mask</code>', to reduce the image to
4457 just the pixels that need to be overlaid. </td>
4461 <td valign="top">coalesce</td>
4462 <td valign="top">Equivalent to a call to the <a href="command-line-options.html#coalesce">-coalesce</a> operator. Apply the layer disposal methods set in the
4463 current image sequence to form a fully defined animation sequence, as
4464 it should be displayed. Effectively converting a GIF animation into a
4465 'film strip'-like animation. </td>
4469 <td valign="top">composite</td>
4470 <td valign="top">Alpha Composition of two image lists, separated by a
4471 "<code>null:</code>" image, with the destination image list first, and
4472 the source images last. An image from each list are composited
4473 together until one list is finished. The separator image and source
4474 image lists are removed. </td>
4479 <td>The <a href="command-line-options.html#geometry">-geometry</a> offset is adjusted according
4480 to <a href="command-line-options.html#gravity">-gravity</a> in accordance of the virtual
4481 canvas size of the first image in each list. Unlike a normal <a href="command-line-options.html#composite">-composite</a> operation, the canvas offset is also
4482 added to the final composite positioning of each image. </td> </tr>
4485 <td>If one of the image lists only contains one image, that image is
4486 applied to all the images in the other image list, regardless of which
4487 list it is. In this case it is the image meta-data of the list which
4493 <td valign="top">dispose</td>
4494 <td valign="top">This like '<code>coalesce</code>' but shows the look of
4495 the animation after the layer disposal method has been applied, before
4496 the next sub-frame image is overlaid. That is the 'dispose' image that
4497 results from the application of the GIF <a href="command-line-options.html#dispose">-dispose</a> method. This allows you to check what
4498 is going wrong with a particular animation you may be developing.
4503 <td valign="top">flatten</td>
4504 <td valign="top">Create a canvas the size of the first images virtual
4505 canvas using the current <a href="command-line-options.html#background">-background</a> color,
4506 and <a href="command-line-options.html#compose">-compose</a> each image in turn onto that
4507 canvas. Images falling outside that canvas is clipped. Final
4508 image will have a zero virtual canvas offset. </td>
4512 <td>This usually used as one of the final 'image layering' operations
4513 overlaying all the prepared image layers into a final image. </td>
4517 <td>For a single image this method can also be used to fillout a virtual
4518 canvas with real pixels, or to underlay an opaque color to remove
4519 transparency from an image.</td>
4524 <td valign="top">merge</td>
4525 <td valign="top">As 'flatten' method but merging all the given image
4526 layers to create a new layer image just large enough to hold all the
4527 image without clipping or extra space. The new images virtual offset
4528 will preserve the position of the new layer, even if this offset is
4529 negative. The virtual canvas size of the first image is preserved.
4533 <tr><td></td><td>Caution is advised when handling image layers with
4534 negative offsets as few image file formats handle them correctly.
4535 Following this operation method with <a href="command-line-options.html#repage">+repage</a>
4536 will remove the layer offset, and create an image in which all the
4537 overlaid image positions relative to each other is preserved, though
4538 not necessarily exactly where you specified them.
4542 <tr><td></td><td>See also 'trim-bounds' below which is closely related but
4543 without doing the'flatten' to merge the images together. </td>
4547 <td valign="top">mosaic</td>
4548 <td valign="top">As 'flatten' method but expanding the initial canvas size
4549 of the first image in a positive direction only so as to hold all the
4550 image layers. However as a virtual canvas is 'locked' to the origin,
4551 by its own definition, image layers with a negative offsets will still
4552 become clipped by the top and left edges. See 'merge' or 'trim-bounds'
4553 if this could be a problem. </td>
4557 <tr><td></td><td>This method is commonly used to layout individual image
4558 using various offset but without knowing the final canvas size. The
4559 resulting image will, like 'flatten' not have any virtual offset, so
4560 can be saved to any image file format. </td>
4565 <td valign="top">optimize</td>
4566 <td valign="top">Optimize a coalesced animation, into GIF animation using
4567 a number of general techniques. This currently a short cut to
4568 apply both the '<code>optimize-frame</code>', and
4569 '<code>optimize-transparency</code>' methods but may be expanded to
4570 include other optimization methods as they are developed. </td>
4574 <td valign="top">optimize-frame</td>
4575 <td valign="top">Optimize a coalesced animation, into GIF animation by
4576 reducing the number of pixels per frame as much as possible by
4577 attempting to pick the best layer disposal method to use, while ensuring
4578 the result will continue to animate properly. </td>
4581 <tr><td></td><td> There is no guarantee that the best optimization is found.
4582 But then no reasonably fast GIF optimization algorithm can do this.
4583 However this does seem to do better than most other GIF frame
4584 optimizers seen. </td>
4588 <td valign="top">optimize-plus</td>
4589 <td valign="top">As '<code>optimize-frame</code>' but attempt to improve the
4590 overall optimization by adding extra frames to the animation, without
4591 changing the final look or timing of the animation. The frames are
4592 added to attempt to separate the clearing of pixels from the
4593 overlaying of new additional pixels from one animation frame to the
4594 next. If this does not improve the optimization (for the next frame
4595 only), it will fall back to the results of the previous normal
4596 '<code>optimize-frame</code>' technique. </td>
4599 <tr><td></td><td>There is the possibility that the change in the disposal
4600 style will result in a worsening in the optimization of later frames,
4601 though this is unlikely. In other words there no guarantee that it is
4602 better than the normal '<code>optimize-frame</code>' technique. For some
4603 animations however you can get a vast improvement in the final
4604 animation size. </td>
4608 <td valign="top">optimize-transparency</td>
4609 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame
4610 overlay images with transparency, if it does not change the resulting
4611 animation by more than the current <a href="command-line-options.html#fuzz">-fuzz</a> factor.
4615 <tr><td></td><td>This should allow a existing frame optimized GIF animation
4616 to compress into a smaller file size due to larger areas of one
4617 (transparent) color rather than a pattern of multiple colors repeating
4618 the current disposed image of the last frame. </td>
4622 <td valign="top">remove-dups</td>
4623 <td valign="top">Remove (and merge time delays) of duplicate consecutive
4624 images, so as to simplify layer overlays of coalesced animations.
4628 <tr><td></td><td>Usually this a result of using a constant time delay
4629 across the whole animation, or after a larger animation was split into
4630 smaller sub-animations. The duplicate frames could also have been
4631 used as part of some frame optimization methods. </td>
4635 <td valign="top">remove-zero</td>
4636 <td valign="top">Remove any image with a zero time delay, unless ALL the
4637 images have a zero time delay (and is not a proper timed animation, a
4638 warning is then issued). </td>
4641 <tr><td></td><td>In a GIF animation, such images are usually frames which
4642 provide partial intermediary updates between the frames that are
4643 actually displayed to users. These frames are usually added for
4644 improved frame optimization in GIF animations. </td>
4648 <td valign="top">trim-bounds</td>
4649 <td valign="top">Find the bounds of all the images in the current
4650 image sequence, then adjust the offsets so all images are contained on
4651 a minimal positive canvas. None of the image data is modified or
4652 merged, only the individual image virtual canvas size and offset.
4653 All the images is given the same canvas size, and and will have
4654 a positive offset, but will remain in the same position relative to
4655 each other. As a result of the minimal canvas size at least one image
4656 will touch every edge of that canvas. The image data touching those
4657 edges however may be transparent. </td>
4660 <tr><td></td><td>The result is much like if you used 'merge' followed by a
4661 <a href="command-line-options.html#repage">+repage</a> option, except that all the images
4662 have been kept separate. If 'flatten' is used after using
4663 'trim-bounds' you will get the same result. </td>
4669 <p>To print a complete list of layer types, use <a href="command-line-options.html#list">-list layers</a>.</p>
4671 <p>The operators <a href="command-line-options.html#coalesce">-coalesce</a>, <a href="command-line-options.html#deconstruct">-deconstruct</a>, <a href="command-line-options.html#flatten">-flatten</a>, and <a href="command-line-options.html#mosaic">-mosaic</a> are only aliases for the above methods and may be depreciated in
4672 the future. Also see <a href="command-line-options.html#page">-page</a>, <a href="command-line-options.html#repage">-repage</a> operators, the <a href="command-line-options.html#compose">-compose</a> setting, and the
4673 GIF <a href="command-line-options.html#dispose">-dispose</a> and <a href="command-line-options.html#delay">-delay</a>
4677 <div style="margin: auto;">
4678 <h4><a id="level"></a>-level <em class="arg">black_point</em>{,<em class="arg">white_point</em>}{<em class="arg">%</em>}{,<em class="arg">gamma</em>}</h4>
4681 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">adjust the level of image channels.</td><td style="text-align:right;"></td></tr></table>
4683 <p>Given one, two or three values delimited with commas: black-point,
4684 white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
4685 white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to
4686 100%; if the white point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center contrast changes.
4687 If a <code>%</code> sign is present anywhere in the string, both black and white
4688 points are percentages of the full color range. Gamma will do a <a href="command-line-options.html#gamma">-gamma</a> adjustment of the values. If it is omitted, the
4689 default of 1.0 (no gamma correction) is assumed.</p>
4691 <p>In normal usage (<code>-level</code>) the image values are stretched so that
4692 the given '<code>black_point</code>' value in the original image is set to zero
4693 (or black), while the given '<code>white_point</code>' value is set to <em class="QR">QuantumRange</em> (or white). This provides you with direct
4694 contrast adjustments to the image. The '<code>gamma</code>' of the resulting
4695 image will then be adjusted. </p>
4697 <p>From ImageMagick v6.4.1-9 using the plus form of the operator
4698 (<code>+level</code>) or adding the special '!' flag anywhere in the argument
4699 list, will cause the operator to do the reverse of the level adjustment. That
4700 is a zero, or <em class="QR">QuantumRange</em> value (black, and white, resp.)
4701 in the original image, is adjusted to the given level values, allowing you to
4702 de-contrast, or compress the channel values within the image. The
4703 '<code>gamma</code>' is adjusted before the level adjustment to de-contrast the
4706 <p>Only the channels defined by the current <a href="command-line-options.html#channel">-channel</a>
4707 setting are adjusted (defaults to RGB color channels only), allowing you to
4708 limit the effect of this operator. </p>
4710 <p>Please note that the transparency channel is treated as 'matte'
4711 values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
4714 <div style="margin: auto;">
4715 <h4><a id="level-colors"></a>-level-colors {<em class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4>
4718 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">adjust the level of an image using the provided dash separated colors.</td><td style="text-align:right;"></td></tr></table>
4720 <p>This function is exactly like <a href="command-line-options.html#level">-level</a>, except that the
4721 value value for each color channel is determined by the
4722 '<code>black_color</code>' and '<code>white_color</code>' colors given (as
4723 described under the <a href="command-line-options.html#fill">-fill</a> option). </p>
4725 <p>This effectually means the colors provided to <code>-level-colors</code>
4726 is mapped to become 'black' and 'white' respectively, with all the other
4727 colors linearly adjusted (or clipped) to match that change. Each channel is
4728 adjusted separately using the channel values of the colors specified. </p>
4730 <p>On the other hand the plus form of the operator (<code>+level-colors</code>)
4731 will map the image color 'black' and 'white' to the given colors
4732 respectively, resulting in a gradient (de-contrasting) tint of the image to
4733 those colors. This can also be used to convert a plain gray-scale image into a
4734 one using the gradient of colors specified. </p>
4736 <p>By supplying a single color with a comma separator either before or after
4737 that color, will just replace the respective 'black' or 'white' point
4738 respectively. But if no comma separator is provided, the given color is
4739 used for both the black and white color points, making the operator either
4740 threshold the images around that color (- form) or set all colors to that
4741 color (+ form). </p>
4744 <div style="margin: auto;">
4745 <h4><a id="limit"></a>-limit <em class="arg">type value</em></h4>
4748 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the pixel cache resource limit.</td><td style="text-align:right;"></td></tr></table>
4750 <p>Choose from: <code>area</code>, <code>disk</code>, <code>file</code>,
4751 <code>map</code>, <code>memory</code>, <code>threads</code>, or <code>time</code>.</p>
4753 <p>The value for <code>file</code> is in number of files. The other limits are
4754 in bytes. Define arguments for the memory, map, area, and disk resource limits
4755 with SI prefixes (.e.g 100MB).</p>
4757 <p>By default the limits are 768 files, 3GB of image area, 1.5GiB memory, 3GiB
4758 memory map, and 18.45EB of disk. These limits are adjusted relative to the
4759 available resources on your computer if this information is available. When
4760 any limit is reached, ImageMagick fails in some fashion but attempts to take
4761 compensating actions, if possible. For example, the following limits
4765 -limit memory 32MiB -limit map 64MiB
4768 <p>Use <a href="command-line-options.html#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
4770 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">identify -list resource</span><span class="crtout"></span></p><pre class="text">
4771 File Area Memory Map Disk Thread Time
4772 ------------------------------------------------------------------------------
4773 768 12.404GB 8.6642GiB 23.104GiB 18.446744EB 8 unlimited
4776 <p>Requests for pixel storage to keep intermediate images are satisfied by one
4777 of three resource categories: in-memory pool, memory-mapped files pool, and
4778 disk pool (in that order) depending on the <a href="command-line-options.html#limit">‑limit</a> settings
4779 and whether the system honors a resource request. If the total size of
4780 allocated pixel storage in the given pool reaches the corresponding limit, the
4781 request is passed to the next pool. Additionally, requests that exceed the
4782 <code>area</code> limit automagically are allocated on disk.</p>
4784 <p>To illustrate how ImageMagick utilizes resource limits, consider a typical
4785 image resource request. First, ImageMagick tries to allocate the pixels in
4786 memory. The request might be denied if the resource request exceeds the
4787 <code>memory</code> limit or if the system does not honor the request. If
4788 a memory request is not honored, the pixels are allocated to disk and the file
4789 is memory-mapped. However, if the allocation request exceeds the
4790 <code>map</code> limit, the resource allocation goes to disk. In all cases, if
4791 the resource request exceeds the <code>area</code> limit, the pixels are
4792 automagically cached to disk. If the disk has a hard limit, the program
4795 <p>In most cases you simply do not need to concern yourself with resource
4796 limits. ImageMagick chooses reasonable defaults and most images do not tax
4797 your computer resources. Where limits do come in handy is when you process
4798 images that are large or on shared systems where ImageMagick can consume all
4799 or most of the available memory. In this case, the ImageMagick workflow slows
4800 other processes or, in extreme cases, brings the system to a halt. Under
4801 these circumstances, setting limits give some assurances that the ImageMagick
4802 workflow will not interfere with other concurrent uses of the computer. For
4803 example, assume you have a web interface that processes images uploaded from
4804 the Internet. To assure ImageMagick does not exceed 10MiB of memory you can
4805 simply set the area limit to 10MiB:</p>
4811 <p>Now whenever a large image is processed, the pixels are automagically
4812 cached to disk instead of memory. This of course implies that large images
4813 typically process very slowly, simply because pixel processing in memory can
4814 be an order of magnitude faster than on disk. Because your web site users
4815 might inadvertently upload a huge image to process, you should set a disk
4819 -limit area 10MB -limit disk 500MB
4822 <p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
4824 <p>In addition to command-line resource limit option, resources can be set
4825 with <a href="resources.html#environment">environment variables</a>. Set the
4826 environment variables <code>MAGICK_AREA_LIMIT</code>,
4827 <code>MAGICK_DISK_LIMIT</code>, <code>MAGICK_FILE_LIMIT</code>,
4828 <code>MAGICK_MEMORY_LIMIT</code>, <code>MAGICK_MAP_LIMIT</code>,
4829 <code>MAGICK_THREAD_LIMIT</code>, <code>MAGICK_TIME_LIMIT</code> for limits of
4830 image area, disk space, open files, heap memory, memory map, number of threads
4831 of execution, and maximum elapsed time in seconds respectively.</p>
4833 <p> Inquisitive users can try adding <a href="command-line-options.html#debug">-debug cache</a> to
4834 their commands and then scouring the generated output for references to the
4835 pixel cache, in order to determine how the pixel cache was allocated and how
4836 resources were consumed. Advanced Unix/Linux users can pipe that output
4837 through <code>grep memory|open|destroy|disk</code> for more readable sifting.
4840 <p>For more about ImageMagick's use of resources, see the section <b>Cache
4841 Storage and Resource Requirements</b> on the <a href="architecture.html#cache ">Architecture</a> page. </p>
4843 <div style="margin: auto;">
4844 <h4><a id="linear-stretch"></a>-linear-stretch <em class="arg">black-point</em><br></br>-linear-stretch <em class="arg">black-point</em>{x<em class="arg">white-point</em>}{<em class="arg">%</em>}}</h4>
4847 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Linear with saturation stretch.</td><td style="text-align:right;"></td></tr></table>
4849 <p>This is very similar to <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a>,
4850 and uses a 'histogram bin' to determine the range of color values that needs to
4851 be stretched. However it then stretches those colors using the <a href="command-line-options.html#level">-level</a> operator.</p>
4853 <p>As such while the initial determination may have 'binning' round off
4854 effects, the image colors are stretched mathematically, rather than using the
4855 histogram bins. This makes the operator more accurate. </p>
4857 <p>note however that a <a href="command-line-options.html#linear-stretch">-linear-stretch</a> of
4858 '<code>0</code>' does nothing, while a value of '<code>1</code>' does a near
4859 perfect stretch of the color range. </p>
4861 <p>See also <a href="command-line-options.html#auto-level">-auto-level</a> for a 'perfect'
4862 normalization of mathematical images. </p>
4864 <p>This operator is under review for re-development. </p>
4867 <div style="margin: auto;">
4868 <h4><a id="linewidth"></a>-linewidth</h4>
4871 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">the line width for subsequent draw operations.</td><td style="text-align:right;"></td></tr></table>
4873 <div style="margin: auto;">
4874 <h4><a id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4>
4877 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">rescale image with seam-carving.</td><td style="text-align:right;"></td></tr></table>
4879 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4881 <div style="margin: auto;">
4882 <h4><a id="list"></a>-list <em class="arg">type</em></h4>
4885 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Print a list of supported arguments for various options or settings. Choose from these list types:</td><td style="text-align:right;"></td></tr></table>
4888 Align Alpha Boolean Channel
4889 Class ClipPath Coder Color
4890 Colorspace Command Compose Compress
4891 Configure DataType Debug Decoration
4892 Delegate Direction Dispose Distort
4893 Dither Endian Evaluate FillRule
4894 Filter Font Format Function
4895 Gravity ImageList Intent Interlace
4896 Interpolate Kernel Layers LineCap
4897 LineJoin List Locale LogEvent
4898 Log Magic Method Metric
4899 Mime Mode Morphology Module
4900 Noise Orientation Policy PolicyDomain
4901 PolicyRights Preview Primitive QuantumFormat
4902 Resource SparseColor Storage Stretch
4903 Style Threshold Type Units
4904 Validate VirtualPixel
4907 <p>These lists vary depending on your version of ImageMagick. Use "<code>-list
4908 list</code>" to get a complete listing of all the "<code>-list</code>" arguments
4911 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">identify -list list</span></p>
4912 <div style="margin: auto;">
4913 <h4><a id="log"></a>-log <em class="arg">string</em></h4>
4916 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Specify format for debug log.</td><td style="text-align:right;"></td></tr></table>
4918 <p>This option specifies the format for the log printed when the <a href="command-line-options.html#debug">-debug</a> option is active.</p>
4920 <p>You can display the following components by embedding special format
4940 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert -debug coders -log "%u %m:%l %e" in.gif out.png</span></p>
4941 <p>The default behavior is to print all of the components.</p>
4943 <div style="margin: auto;">
4944 <h4><a id="loop"></a>-loop <em class="arg">iterations</em></h4>
4947 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">add Netscape loop extension to your GIF animation.</td><td style="text-align:right;"></td></tr></table>
4949 <p>Set iterations to zero to repeat the animation an infinite number of times,
4950 otherwise the animation repeats itself up to <em class="arg">iterations</em>
4953 <div style="margin: auto;">
4954 <h4><a id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4>
4957 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">when comparing images, de-emphasize pixel differences with this color.</td><td style="text-align:right;"></td></tr></table>
4959 <div style="margin: auto;">
4960 <h4><a id="magnify"></a>-magnify</h4>
4963 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">double the size of the image with pixel art scaling.</td><td style="text-align:right;"></td></tr></table>
4966 <div style="margin: auto;">
4967 <h4><a id="map"></a>-map <em class="arg">type</em></h4>
4970 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Display image using this <em class="arg">type</em>.</td><td style="text-align:right;">[<a href="animate.html">animate</a>, <a href="display.html">display</a>]</td></tr></table>
4972 <p>Choose from these <em class="arg">Standard Colormap</em> types:</p>
4983 <p>The <em class="arg">X server</em> must support the <em class="arg">Standard
4984 Colormap</em> you choose, otherwise an error occurs. Use <code>list</code> as
4985 the type and <code>display</code> searches the list of colormap types in
4986 <code>top-to-bottom</code> order until one is located. See <em class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p>
4989 <div style="margin: auto;">
4990 <h4><a id="map_stream_"></a>-map <em class="arg">components</em></h4>
4993 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">pixel map.</td><td style="text-align:right;">[<a href="stream.html">stream</a>]</td></tr></table>
4995 <p>Here are the valid components of a map:</p>
4998 r red pixel component
4999 g green pixel component
5000 b blue pixel component
5001 a alpha pixel component (0 is transparent)
5002 o opacity pixel component (0 is opaque)
5003 i grayscale intensity pixel component
5004 c cyan pixel component
5005 m magenta pixel component
5006 y yellow pixel component
5007 k black pixel component
5008 p pad component (always 0)
5011 <p>You can specify as many of these components as needed in any order (e.g.
5012 bgr). The components can repeat as well (e.g. rgbr).</p>
5015 <div style="margin: auto;">
5016 <h4><a id="mask"></a>-mask
5017 <em class="arg">filename</em></h4>
5020 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Prevent updates to image pixels specified by the mask.</td><td style="text-align:right;"></td></tr></table>
5022 <p>This the same as using a mask used for composite masking operations, with
5023 grayscale values causing blended updates of the image the mask is attached to.
5026 <p>Use <a href="command-line-options.html#mask">+mask</a> to remove the mask from images.</p>
5028 <p>Also see <a href="command-line-options.html#clip-mask">-clip-mask</a> which work in the same way,
5029 but with strict boolean masking. </p>
5031 <div style="margin: auto;">
5032 <h4><a id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4>
5035 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Specify the color to be used with the <a href="command-line-options.html#frame">-frame</a> option.</td><td style="text-align:right;"></td></tr></table>
5037 <p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
5039 <p>The default matte color is <code>#BDBDBD</code>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p>
5041 <div style="margin: auto;">
5042 <h4><a id="maximum"></a>-maximum</h4>
5045 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">return the maximum intensity of an image sequence.</td><td style="text-align:right;"></td></tr></table>
5047 <p>Select the 'maximum' value from all the surrounding pixels. </p>
5049 <p>This is legacy option from the <a href="command-line-options.html#statistic">method</a> of the same
5052 <div style="margin: auto;">
5053 <h4><a id="median"></a>-median <em class="arg">geometry</em></h4>
5056 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">apply a median filter to the image.</td><td style="text-align:right;"></td></tr></table>
5058 <p>Select the 'middle' value from all the surrounding pixels. </p>
5060 <p>This is legacy option from the <a href="command-line-options.html#statistic">method</a> of the same
5063 <div style="margin: auto;">
5064 <h4><a id="metric"></a>-metric <em class="arg">type</em></h4>
5067 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Output to STDERR a measure of the differences between images according to the <em class="arg">type</em> given metric.</td><td style="text-align:right;"></td></tr></table>
5072 AE absolute error count, number of different pixels (-fuzz effected)
5073 FUZZ mean color distance
5074 MAE mean absolute error (normalized), average channel error distance
5075 MEPP mean error per pixel (normalized mean error, normalized peak error)
5076 MSE mean error squared, average of the channel error squared
5077 NCC normalized cross correlation
5078 PAE peak absolute (normalize peak absolute)
5079 PSNR peak signal to noise ratio
5080 RMSE root mean squared (normalized root mean squared)
5083 <p>Control the '<code>AE</code>', or absolute count of pixels that are different,
5084 with the <a href="command-line-options.html#fuzz">-fuzz</a> factor (ignore pixels which
5085 only changed by a small amount). Use '<code>PAE</code>' to find the
5086 size of the <a href="command-line-options.html#fuzz">-fuzz</a> factor needed to make all pixels
5087 'similar', while '<code>MAE</code>' determines the factor needed
5088 for about half the pixels to be similar. </p>
5090 <p>The '<code>MEPP</code>' metric returns three different metrics
5091 ('<code>MAE</code>', '<code>MAE</code>' normalized, and '<code>PAE</code>'
5092 normalized) from a single comparison run. </p>
5094 <p>To print a complete list of metrics, use the <a href="command-line-options.html#list">-list
5095 metric</a> option.</p>
5098 <div style="margin: auto;">
5099 <h4><a id="minimum"></a>-minimum</h4>
5102 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">return the minimum intensity of an image sequence.</td><td style="text-align:right;"></td></tr></table>
5104 <p>Select the 'minimal' value from all the surrounding pixels. </p>
5106 <p>This is legacy option from the <a href="command-line-options.html#statistic">method</a> of the same
5111 <div style="margin: auto;">
5112 <h4><a id="mode"></a>-mode <em class="arg">geometry</em></h4>
5115 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">make each pixel the 'predominant color' of the neighborhood.</td><td style="text-align:right;">[<a href="convert.html">convert</a>, <a href="mogrify.html">mogrify</a>]</td></tr></table>
5117 <div style="margin: auto;">
5118 <h4>-mode <em class="arg">value</em></h4>
5121 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Mode of operation.</td><td style="text-align:right;">[<a href="montage.html">montage</a>]</td></tr></table>
5123 <p>Choose the <em class="arg">value</em> from these styles: <code>Frame,
5124 Unframe, or Concatenate</code></p>
5126 <p>Use the <a href="command-line-options.html#list">-list</a> option with a '<code>Mode</code>' argument
5127 for a list of <a href="command-line-options.html#mode">-mode</a> arguments available in your
5128 ImageMagick installation.</p>
5131 <div style="margin: auto;">
5132 <h4><a id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4>
5135 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Vary the <em class="arg">brightness</em>, <em class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style="text-align:right;"></td></tr></table>
5137 <p>The arguments are given as a percentages of variation. A value of 100 means
5138 no change, and any missing values are taken to mean 100.</p>
5140 <p>The <em class="arg">brightness</em> is a multiplier of the overall
5141 brightness of the image, so 0 means pure black, 50 is half as bright, 200 is
5142 twice as bright. To invert its meaning <a href="command-line-options.html#negate">-negate</a> the image
5143 before and after. </p>
5145 <p>The <em class="arg">saturation</em> controls the amount of color in an
5146 image. For example, 0 produce a grayscale image, while a large value such as
5147 200 produce a very colorful, 'cartoonish' color.</p>
5149 <p>The <em class="arg">hue</em> argument causes a "rotation" of the colors
5150 within the image by the amount specified. For example, 50 results in
5151 a counter-clockwise rotation of 90, mapping red shades to purple, and so on.
5152 A value of either 0 or 200 results in a complete 180 degree rotation of the
5153 image. Using a value of 300 is a 360 degree rotation resulting in no change to
5154 the original image. </p>
5156 <p>For example, to increase the color brightness by 20% and decrease the color
5157 saturation by 10% and leave the hue unchanged, use <a href="command-line-options.html#modulate">-modulate 120,90</a>.</p>
5159 <p>Use <a href="command-line-options.html#set">-set</a> attribute of '<code class="arg">option:modulate:colorspace</code>' to specify which colorspace to
5160 modulate. Choose from <code>HCL</code>, <code>HCLp</code>, <code>HSB</code>, <code>HSI</code>, <code>HSL</code> (the default), <code>HSV</code>, <code>HWB</code>, or <code>LCH</code> (LCHuv). For example,</p>
5162 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert image.png -set option:modulate:colorspace hsb -modulate 120,90 modulate.png</span></p>
5164 <div style="margin: auto;">
5165 <h4><a id="monitor"></a>-monitor</h4>
5168 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">monitor progress.</td><td style="text-align:right;"></td></tr></table>
5171 <div style="margin: auto;">
5172 <h4><a id="monochrome"></a>-monochrome</h4>
5175 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">transform the image to black and white.</td><td style="text-align:right;"></td></tr></table>
5177 <div style="margin: auto;">
5178 <h4><a id="morph"></a>-morph <em class="arg">frames</em></h4>
5181 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">morphs an image sequence.</td><td style="text-align:right;"></td></tr></table>
5183 <p>Both the image pixels and size are linearly interpolated to give the
5184 appearance of a metamorphosis from one image to the next, over all the images
5185 in the current image list. The added images are the equivalent of a <a href="command-line-options.html#blend">-blend</a> composition. The <em class="arg">frames</em>
5186 argument determine how many images to interpolate between each image. </p>
5189 <div style="margin: auto;">
5190 <h4><a id="morphology"></a>-morphology</h4>
5191 <h4>-morphology <em class="arg">method</em> <em class="arg">kernel</em></h4>
5194 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">apply a morphology method to the image.</td><td style="text-align:right;"></td></tr></table>
5196 <p>Until I get around to writing an option summary for this, see <a href="http://www.imagemagick.org/Usage/morphology/">IM Usage Examples,
5197 Morphology</a>. </p>
5200 <div style="margin: auto;">
5201 <h4><a id="mosaic"></a>-mosaic</h4>
5204 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">an simple alias for the <a href="command-line-options.html#layers">-layers</a> method "mosaic"</td><td style="text-align:right;"></td></tr></table>
5207 <div style="margin: auto;">
5208 <h4><a id="motion-blur"></a>-motion-blur <em class="arg">radius</em><br></br>-motion-blur <em class="arg">radius</em>x<em class="arg">sigma</em>+<em class="arg">angle</em>+<em class="arg">bias</em></h4>
5211 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">simulate motion blur.</td><td style="text-align:right;"></td></tr></table>
5213 <p>Blur with the given radius, standard deviation (sigma), and angle. The
5214 angle given is the angle toward which the image is blurred. That is the
5215 direction people would consider the object is coming from. </p>
5217 <p>Note that the blur is not uniform distribution, giving the motion a
5218 definite sense of direction of movement. </p>
5220 <p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
5221 pixels which are outside the image proper are blurred into the final result.
5224 <div style="margin: auto;">
5225 <h4><a id="name"></a>-name</h4>
5228 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">name an image.</td><td style="text-align:right;"></td></tr></table>
5229 <div style="margin: auto;">
5230 <h4><a id="negate"></a>-negate</h4>
5233 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">replace each pixel with its complementary color.</td><td style="text-align:right;"></td></tr></table>
5235 <p>The red, green, and blue intensities of an image are negated. White becomes
5236 black, yellow becomes blue, etc. Use <a href="command-line-options.html#negate">+negate</a> to only
5237 negate the grayscale pixels of the image.</p>
5239 <div style="margin: auto;">
5240 <h4><a id="noise"></a>-noise <em class="arg">geometry</em><br></br>
5241 +noise <em class="arg">type</em></h4>
5244 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Add or reduce noise in an image.</td><td style="text-align:right;"></td></tr></table>
5246 <p>The principal function of noise peak elimination filter is to smooth the
5247 objects within an image without losing edge information and without creating
5248 undesired structures. The central idea of the algorithm is to replace a pixel
5249 with its next neighbor in value within a pixel window, if this pixel has been
5250 found to be noise. A pixel is defined as noise if and only if this pixel is
5251 a maximum or minimum within the pixel window.</p>
5253 <p>Use <code><a href="command-line-options.html#noise">-noise</a> <em class="arg">radius</em></code> to
5254 specify the width of the neighborhood when reducing noise. This is equivelent
5255 to using a <code><a href="command-line-options.html#statistic">-statistic</a> NonPeak</code> operation,
5256 which should be used in preference.</p>
5258 <p>Use <a href="command-line-options.html#noise">+noise</a> followed by a noise <em class="arg">type</em> to add noise to an image. Choose from these noise
5271 <p>The amount of noise added can be controled by the <code><a href="command-line-options.html#attunuuate">-attenuate</a></code> setting. If unset the value is
5272 equivelent to 1.0, or a maximum noise addition.</p>
5274 <p>Note that Random will replace the image with noise rather than add noise to the image. Use Uniform, if you wish to add random noise to the image.</p>
5276 <p>To print a complete list of noises, use the <a href="command-line-options.html#list">-list noise</a> option.</p>
5278 <p>Also see the <a href="command-line-options.html#evaluate">-evaluate</a> noise functions that allows
5279 the use of a controlling value to specify the amount of noise that should be
5280 added to an image. </p>
5283 <div style="margin: auto;">
5284 <h4><a id="normalize"></a>-normalize</h4>
5287 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Increase the contrast in an image by <em>stretching</em> the range of intensity values.</td><td style="text-align:right;"></td></tr></table>
5289 <p>The intensity values are stretched to cover the entire range of possible
5290 values. While doing so, black-out at most <em>2%</em> of the pixels and
5291 white-out at most <em>1%</em> of the pixels.</p>
5293 <p>Note that as of ImageMagick 6.4.7-0, <a href="command-line-options.html#normalize">-normalize</a>
5294 is equivalent to <a href="command-line-options.html#contrast-stretch">-contrast-stretch 2%x1%</a>.
5295 (Before this version, it was equivalent to <a href="command-line-options.html#contrast-stretch">-contrast-stretch 2%x99%</a>).</p>
5297 <p>All the channels are normalized in concert by the came amount so as to
5298 preserve color integrity, when the default <a href="command-line-options.html#channel">+channel</a>
5299 setting is in use. Specifying any other <a href="command-line-options.html#channel">-channel</a>
5300 setting will normalize the RGB channels independently.</p>
5302 <p>See <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a> for more details.
5303 Also see <a href="command-line-options.html#auto-level">-auto-level</a> for a 'perfect' normalization
5304 that is better suited to mathematically generated images. </p>
5306 <p>This operator is under review for re-development. </p>
5309 <div style="margin: auto;">
5310 <h4><a id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4>
5313 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">dither the image using a pre-defined ordered dither <em class="arg">threshold map</em> specified, and a uniform color map with the
5314 given number of <em class="arg">levels</em> per color channel . </td><td style="text-align:right;"></td></tr></table>
5316 <p>You can choose from these standard threshold maps:</p>
5319 threshold 1x1 Threshold 1x1 (non-dither)
5320 checks 2x1 Checkerboard 2x1 (dither)
5321 o2x2 2x2 Ordered 2x2 (dispersed)
5322 o3x3 3x3 Ordered 3x3 (dispersed)
5323 o4x4 4x4 Ordered 4x4 (dispersed)
5324 o8x8 8x8 Ordered 8x8 (dispersed)
5325 h4x4a 4x1 Halftone 4x4 (angled)
5326 h6x6a 6x1 Halftone 6x6 (angled)
5327 h8x8a 8x1 Halftone 8x8 (angled)
5328 h4x4o Halftone 4x4 (orthogonal)
5329 h6x6o Halftone 6x6 (orthogonal)
5330 h8x8o Halftone 8x8 (orthogonal)
5331 h16x16o Halftone 16x16 (orthogonal)
5332 c5x5b c5x5 Circles 5x5 (black)
5333 c5x5w Circles 5x5 (white)
5334 c6x6b c6x6 Circles 6x6 (black)
5335 c6x6w Circles 6x6 (white)
5336 c7x7b c7x7 Circles 7x7 (black)
5337 c7x7w Circles 7x7 (white)
5340 <p> The <code>threshold</code> generated a simple 50% threshold of the image.
5341 This could be used with <em class="arg">level</em> to do the equivalent of <a href="command-line-options.html#posterize">-posterize</a> to reduce an image to basic primary colors.
5344 <p>The <code>checks</code> pattern produces a 3 level checkerboard dither
5345 pattern. That is a grayscale will become a pattern of solid black, solid
5346 white, and mid-tone colors into a checkerboard pattern of black and white.
5349 <p>You can define your own <em class="arg">threshold map</em> for ordered
5350 dithering and halftoning your images, in either personal or system
5351 <code>thresholds.xml</code> XML file. See <a href="resources.html">Resources</a>
5352 for more details of configuration files. </p>
5354 <p>To print a complete list of the thresholds that have been defined, use the
5355 <a href="command-line-options.html#list">-list threshold</a> option.</p>
5357 <p>Note that at this time the same threshold dithering map is used for all
5358 color channels, no attempt is made to offset or rotate the map for different
5359 channels is made, to create an offset printing effect. Also as the maps are
5360 simple threshold levels, the halftone and circle maps will create incomplete
5361 circles along the edges of a colored area. Also all the effects are purely
5362 on/off boolean effects, without anti-aliasing to make the circles smooth
5363 looking. Large dots can be made to look better with a small amount of blurring
5364 after being created. </p>
5367 <div style="margin: auto;">
5368 <h4><a id="opaque"></a>-opaque <em class="arg">color</em></h4>
5371 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">change this color to the fill color within the image.</td><td style="text-align:right;"></td></tr></table>
5373 <p>The <em class="arg">color</em> argument is defined using the format
5374 described under the <a href="command-line-options.html#fill">-fill</a> option. The <a href="command-line-options.html#fuzz">-fuzz</a> setting can be used to match and replace colors similar to the one
5377 <p>Use <a href="command-line-options.html#opaque">+opaque</a> to paint any pixel that does not match
5378 the target color. </p>
5380 <p>The <a href="command-line-options.html#transparent">-transparent</a> operator is exactly the same
5381 as <a href="command-line-options.html#opaque">-opaque</a> but replaces the matching color with
5382 transparency rather than the current <a href="command-line-options.html#fill">-fill</a> color setting.
5383 To ensure that it can do this it also ensures that the image has an alpha
5384 channel enabled, as per "<code><a href="command-line-options.html#alpha">-alpha</a> set</code>", for
5385 the new transparent colors, and does not require you to modify the <a href="command-line-options.html#channel">-channel</a> to enable alpha channel handling. </p>
5388 <div style="margin: auto;">
5389 <h4><a id="orient"></a>-orient <em class="arg">image orientation</em></h4>
5392 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">specify orientation of a digital camera image.</td><td style="text-align:right;"></td></tr></table>
5394 <p>Choose from these orientations:</p>
5408 <p>To print a complete list of orientations, use the <a href="command-line-options.html#list">-list
5409 orientation</a> option.</p>
5412 <div style="margin: auto;">
5413 <h4><a id="page"></a>-page <em class="arg">geometry</em><br></br>
5414 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br></br>
5419 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the size and location of an image on the larger virtual canvas.</td><td style="text-align:right;"></td></tr></table>
5421 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5423 <p>For convenience you can specify the page size using <em class="arg">media</em> (see below). Offsets can then be added as with other
5424 <em class="arg">geometry</em> arguments (e.g. <a href="command-line-options.html#page">-page</a> <code>Letter+43+43</code>).</p>
5426 <p>Use <em class="arg">media</em> as shorthand to specify the dimensions (<em class="arg">width</em>x<em class="arg">height</em>) of the <em class="arg">PostScript</em> page in dots per inch or a TEXT page in pixels.
5427 The choices for a PostScript page are:</p>
5429 <table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;">
5432 <th align="center"><em class="arg">media</em></th>
5433 <th align="center"><em class="arg">width</em></th>
5434 <th align="center"><em class="arg">height</em></th>
5438 <tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
5439 <tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
5440 <tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
5441 <tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
5442 <tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
5443 <tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
5444 <tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
5445 <tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
5446 <tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
5447 <tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
5448 <tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
5449 <tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
5450 <tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
5451 <tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
5452 <tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
5453 <tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
5454 <tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
5455 <tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
5456 <tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
5457 <tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
5458 <tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
5459 <tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
5460 <tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
5461 <tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
5462 <tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
5463 <tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
5464 <tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
5465 <tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
5466 <tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
5467 <tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
5468 <tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
5469 <tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
5470 <tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
5471 <tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
5472 <tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
5473 <tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
5474 <tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
5475 <tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
5480 <p>This option is also used to place subimages when writing to a multi-image
5481 format that supports offsets, such as GIF89 and MNG. When used for this
5482 purpose the offsets are always measured from the top left corner of the canvas
5483 and are not affected by the <a href="command-line-options.html#gravity">-gravity</a> option. To
5484 position a GIF or MNG image, use <a href="command-line-options.html#page">-page</a><em class="arg">{+-}x{+-}y</em> (e.g. -page +100+200). When writing to a MNG
5485 file, a <a href="command-line-options.html#page">-page</a> option appearing ahead of the first image in
5486 the sequence with nonzero width and height defines the width and height values
5487 that are written in the <code>MHDR</code> chunk. Otherwise, the MNG width and
5488 height are computed from the bounding box that contains all images in the
5489 sequence. When writing a GIF89 file, only the bounding box method is used to
5490 determine its dimensions.</p>
5492 <p>For a PostScript page, the image is sized as in <a href="command-line-options.html#geometry">-geometry</a> but positioned relative to the <em>lower
5493 left-hand corner</em> of the page by {+-}<code>x</code><em class="arg">offset</em>{+-}<code>y</code> <em class="arg">offset</em>. Use <a href="command-line-options.html#page">-page 612x792</a>, for example, to center the image within the
5494 page. If the image size exceeds the PostScript page, it is reduced to fit the
5495 page. The default gravity for the <a href="command-line-options.html#page">-page</a> option is <em class="arg">NorthWest</em>, i.e., positive <code>x</code> and <code>y</code> <em class="arg">offset</em> are measured rightward and downward from the top left
5496 corner of the page, unless the <a href="command-line-options.html#gravity">-gravity</a> option is
5497 present with a value other than <em class="arg">NorthWest</em>.</p>
5499 <p>The default page dimensions for a TEXT image is 612x792.</p>
5501 <p>This option is used in concert with <a href="command-line-options.html#density">-density</a>.</p>
5503 <p>Use <a href="command-line-options.html#page">+page</a> to remove the page settings for an image.</p>
5505 <div style="margin: auto;">
5506 <h4><a id="paint"></a>-paint <em class="arg">radius</em></h4>
5509 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">simulate an oil painting.</td><td style="text-align:right;"></td></tr></table>
5511 <p>Each pixel is replaced by the most frequent color in a circular
5512 neighborhood whose width is specified with <em class="arg">radius</em>.</p>
5514 <div style="margin: auto;">
5515 <h4><a id="path"></a>-path <em class="arg">path</em></h4></div>
5517 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">write images to this path on disk.</td><td style="text-align:right;"></td></tr></table>
5519 <div style="margin: auto;">
5520 <h4><a id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4>
5523 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Pause between animation loops.</td><td style="text-align:right;">[<a href="animate.html">animate</a>]</td></tr></table>
5525 <p>Pause for the specified number of seconds before repeating the animation.</p>
5527 <div style="margin: auto;">
5528 <h4><a id="pause_import_"></a>-pause <em class="arg">seconds</em></h4>
5531 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Pause between snapshots.</td><td style="text-align:right;">[<a href="import.html">import</a>]</td></tr></table>
5533 <p>Pause for the specified number of seconds before taking the next snapshot.</p>
5535 <div style="margin: auto;">
5536 <h4><a id="perceptible"></a>-perceptible <em class="arg">epsilon</em></h4>
5539 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">set each pixel whose value is less than |<em>epsilon</em>| to <em>-epsilon</em> or <em>epsilon</em> (whichever is closer) otherwise the pixel value remains unchanged.</td><td style="text-align:right;"></td></tr></table>
5541 <div style="margin: auto;">
5542 <h4><a id="ping"></a>-ping</h4>
5545 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">efficiently determine image characteristics.</td><td style="text-align:right;"></td></tr></table>
5547 <div style="margin: auto;">
5548 <h4><a id="pointsize"></a>-pointsize <em class="arg">value</em></h4>
5551 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">pointsize of the PostScript, OPTION1, or TrueType font.</td><td style="text-align:right;"></td></tr></table>
5553 <div style="margin: auto;">
5554 <h4><a id="polaroid"></a>-polaroid <em class="arg">angle</em></h4>
5557 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">simulate a Polaroid picture.</td><td style="text-align:right;"></td></tr></table>
5559 <p>Use <code>+polaroid</code> to rotate the image at a random angle between -15 and +15 degrees.</p>
5561 <div style="margin: auto;">
5562 <h4><a id="poly"></a>-poly <em class="arg">"wt,exp ..."</em></h4>
5565 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">combines multiple images according to a weighted sum of polynomials; one floating point weight (coefficient) and one floating point polynomial exponent (power) for each image expressed as comma separated pairs.</td><td style="text-align:right;"></td></tr></table>
5567 <p> The weights should typically be fractions between -1 and 1. But the sum of weights should be 1 or at least between 0 and 1 to avoid clamping in non-hdri mode at black and white.</p>
5569 <p>The exponents may be positive, negative or zero. A negative exponent is equivalent to 1 divided by the image raised to the corresponding positive exponent. A zero exponent always produces 1 scaled by quantumrange to white, i.e. wt*white, no matter what the image.</p>
5571 <p>The format is: output = wt1*image1^exp1 + wt2*image2^exp2 ...</p>
5573 <p>Some simple uses are:</p>
5575 <li>A weighted sum of each image provided all weights add to unity and all exponents=1. If the the weights are all equal to 1/(number of images), then this is equivalent to <a href="command-line-options.html#profile">-evaluate-sequence</a> <em class="arg">mean</em>.</li>
5576 <li>The sum of squares of two or more images, provided the weights are equal (and sum to 1 to avoid clamping) and the exponents equal 2.</li>
5579 <p>Note that one may add a constant color to the expression simply by using xc:somecolor for one of the images and specifying the desired weight and exponent equal to 0.</p>
5581 <p>Similarly one may add white to the expression by simply using null: (or xc:white) for one of the images with the appropriate weight and exponent equal to 0.</p>
5584 <div style="margin: auto;">
5585 <h4><a id="posterize"></a>-posterize <em class="arg">levels</em></h4>
5588 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">reduce the image to a limited number of color levels per channel.</td><td style="text-align:right;"></td></tr></table>
5590 <p>Very low values of <em class="arg">levels</em>, e.g., 2, 3, 4, have the most
5593 <div style="margin: auto;">
5594 <h4><a id="precision"></a>-precision <em class="arg">value</em></h4>
5597 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">set the maximum number of significant digits to be printed.</td><td style="text-align:right;"></td></tr></table>
5599 <div style="margin: auto;">
5600 <h4><a id="preview"></a>-preview <em class="arg">type</em></h4>
5603 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">image preview type.</td><td style="text-align:right;"></td></tr></table>
5605 <p>Use this option to affect the preview operation of an image (e.g.
5606 <code>convert file.png -preview Gamma Preview:gamma.png</code>). Choose from
5610 Rotate Shear Roll Hue
5611 Saturation Brightness Gamma Spiff
5612 Dull Grayscale Quantize Despeckle
5613 ReduceNoise Add Noise Sharpen Blur
5614 Threshold EdgeDetect Spread Shade
5615 Raise Segment Solarize Swirl
5616 Implode Wave OilPaint CharcoalDrawing
5620 <p>To print a complete list of previews, use the <a href="command-line-options.html#list">-list preview</a> option.</p>
5622 <p>The default preview is <code>JPEG</code>.</p>
5624 <div style="margin: auto;">
5625 <h4><a id="print"></a>-print <em class="arg">string</em></h4>
5628 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">interpret string and print to console.</td><td style="text-align:right;"></td></tr></table>
5630 <div style="margin: auto;">
5631 <h4><a id="process"></a>-process <em class="arg">command</em></h4>
5634 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">process the image with a custom image filter.</td><td style="text-align:right;"></td></tr></table>
5636 <p>The command arguments has the form <code>"module arg1 arg2 arg3 ...
5637 argN"</code> where <code>module</code> is the name of the module to invoke (e.g.
5638 "Analyze") and arg1 arg2 arg3 ... argN are an arbitrary number of arguments to
5639 pass to the process module.</p>
5641 <div style="margin: auto;">
5642 <h4><a id="profile"></a>-profile <em class="arg">filename</em><br></br>
5643 +profile <em class="arg">profile_name</em></h4>
5646 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Manage ICM, IPTC, or generic profiles in an image.</td><td style="text-align:right;"></td></tr></table>
5648 <p>Using <a href="command-line-options.html#profile">-profile</a> <em class="arg">filename</em> adds an
5649 ICM (ICC color management), IPTC (newswire information), or a generic profile
5652 <p>Use <a href="command-line-options.html#profile">+profile <em class="arg">profile_name</em></a> to
5653 remove the indicated profile. ImageMagick uses standard filename globbing, so
5654 wildcard expressions may be used to remove more than one profile. Here we
5655 remove all profiles from the image except for the XMP profile: <code>+profile
5656 "!xmp,*"</code>. </p>
5658 <p>Use <code>identify -verbose</code> to find out which profiles are in the
5659 image file. Use <a href="command-line-options.html#strip">-strip</a> to remove all profiles (and
5662 <p>To extract a profile, the <a href="command-line-options.html#profile">-profile</a> option is not
5663 used. Instead, simply write the file to an image format such as <em class="arg">APP1, 8BIM, ICM,</em> or <em class="arg">IPTC</em>.</p>
5665 <p>For example, to extract the Exif data (which is stored in JPEG files in the
5666 <em class="arg">APP1</em> profile), use.</p>
5668 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert cockatoo.jpg profile.exif</span></p>
5669 <p>It is important to note that results may depend on whether or not the
5670 original image already has an included profile. Also, keep in mind that <a href="command-line-options.html#profile">-profile</a> is an "operator" (as opposed to a "setting") and
5671 therefore a conversion is made each time it is encountered, in order, in the
5672 command-line. For instance, in the following example, if the original image is
5673 CMYK with profile, a CMYK-CMYK-RGB conversion results.</p>
5675 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p>
5676 <p>Furthermore, since ICC profiles are not necessarily symmetric, extra
5677 conversion steps can yield unwanted results. CMYK profiles are often very
5678 asymmetric since they involve 3−>4 and 4−>3 channel mapping.
5681 <div style="margin: auto;">
5682 <h4><a id="quality"></a>-quality <em class="arg">value</em></h4>
5685 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">JPEG/MIFF/PNG compression level.</td><td style="text-align:right;"></td></tr></table>
5687 <p>For the JPEG and MPEG image formats, quality is 1 (lowest image quality and
5688 highest compression) to 100 (best quality but least effective compression).
5689 The default is to use the estimated quality of your input image if it can
5690 be determined, otherwise 92. When the quality is greater than 90, then the
5691 chroma channels are not downsampled.
5692 Use the <a href="command-line-options.html#sampling-factor">-sampling-factor</a> option to specify the
5693 factors for chroma downsampling.</p>
5695 <p>For the MIFF image format, quality/10 is the zlib compression level, which
5696 is 0 (worst but fastest compression) to 9 (best but slowest). It has no effect
5697 on the image appearance, since the compression is always lossless.</p>
5699 <p>For the JPEG-2000 image format, quality is mapped using a non-linear
5700 equation to the compression ratio required by the Jasper library. This
5701 non-linear equation is intended to loosely approximate the quality provided by
5702 the JPEG v1 format. The default quality value 100, a request for non-lossy
5703 compression. A quality of 75 results in a request for 16:1 compression.</p>
5705 <p>For the MNG and PNG image formats, the quality value sets the zlib
5706 compression level (quality / 10) and filter-type (quality % 10). The default
5707 PNG "quality" is 75, which means compression level 7 with adaptive PNG
5708 filtering, unless the image has a color map, in which case it means
5709 compression level 7 with no PNG filtering.</p>
5711 <p>For compression level 0, the Huffman-only strategy is used, which is
5712 fastest but not necessarily the worst compression.</p>
5714 <p>If filter-type is 4 or less, the specified PNG filter-type is used for
5725 <p>If filter-type is 5, adaptive filtering is used when quality is greater
5726 than 50 and the image does not have a color map, otherwise no filtering is
5729 <p>If filter-type is 6, adaptive filtering
5730 with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p>
5732 <p>Only if the output is MNG, if filter-type is 7, the LOCO color
5733 transformation (intrapixel differencing) and adaptive filtering
5734 with <em class="arg">minimum-sum-of-absolute-values</em> are used.</p>
5736 <p>If the filter-type is 8 the zlib Z_RLE compression strategy is used with
5737 no PNG filtering.</p>
5739 <p>If the filter-type is 9 the zlib Z_RLE compression strategy is used with
5740 adaptive PNG filtering.</p>
5742 <p>The quality setting has no effect on the appearance or signature of PNG
5743 and MNG images, since the compression is always lossless.</p>
5745 <p>Not all combinations of compression level, strategy, and PNG filter type
5746 can be obtained using the -quality option. For more precise control,
5747 you can use the PNG:compression-level=N, PNG:compression-strategy=N, and
5748 PNG:compression-filter=N defines, respectively, instead.
5749 See <a href="command-line-options.html#define">-define</a>. Values from the defines take precedence
5750 over values from the -quality option.</p>
5752 <p>For further information, see
5753 the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
5755 <div style="margin: auto;">
5756 <h4><a id="quantize"></a>-quantize <em class="arg">colorspace</em></h4>
5759 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">reduce colors using this colorspace.</td><td style="text-align:right;"></td></tr></table>
5761 <p>This setting defines the colorspace used to sort out and reduce the number
5762 of colors needed by an image (for later dithering) by operators such as <a href="command-line-options.html#colors">-colors</a>, Note that color reduction also happens
5763 automatically when saving images to color-limited image file formats, such as
5767 <div style="margin: auto;">
5768 <h4><a id="quiet"></a>-quiet</h4>
5771 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">suppress all warning messages. Error messages are still reported.</td><td style="text-align:right;"></td></tr></table>
5773 <div style="margin: auto;">
5774 <h4><a id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4>
5777 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Blur around the center of the image.</td><td style="text-align:right;"></td></tr></table>
5779 <p>Note that this is actually a rotational blur rather than a radial and as
5780 such actually mis-named. </p>
5782 <p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
5783 pixels which are outside the image proper are blurred into the final result.
5787 <div style="margin: auto;">
5788 <h4><a id="raise"></a>-raise <em class="arg">thickness</em></h4>
5791 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Lighten or darken image edges.</td><td style="text-align:right;"></td></tr></table>
5793 <p>This will create a 3-D effect. Use <a href="command-line-options.html#raise">-raise</a> to create
5794 a raised effect, otherwise use <a href="command-line-options.html#raise">+raise</a>. </p>
5796 <p>Unlike the similar <a href="command-line-options.html#frame">-frame</a> option, <a href="command-line-options.html#raise">-raise</a> does not alter the dimensions of the image.</p>
5798 <div style="margin: auto;">
5799 <h4><a id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4>
5802 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Apply a random threshold to the image.</td><td style="text-align:right;"></td></tr></table>
5804 <div style="margin: auto;">
5805 <h4><a id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4>
5808 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the red chromaticity primary point.</td><td style="text-align:right;"></td></tr></table>
5810 <div style="margin: auto;">
5811 <h4><a id="regard-warnings"></a>-regard-warnings</h4>
5814 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Pay attention to warning messages.</td><td style="text-align:right;"></td></tr></table>
5816 <p>This option causes some warnings in some image formats to be treated
5819 <div style="margin: auto;">
5820 <h4><a id="remap"></a>-remap <em class="arg">filename</em></h4>
5823 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Reduce the number of colors in an image to the colors used by this image.</td><td style="text-align:right;"></td></tr></table>
5825 <p>If the <a href="command-line-options.html#dither">-dither</a> setting is enabled (the default) then
5826 the given colors are dithered over the image as necessary, otherwise the closest
5827 color (in RGB colorspace) is selected to replace that pixel in the image. </p>
5829 <p>As a side effect of applying a <a href="command-line-options.html#remap">-remap</a> of colors across all
5830 images in the current image sequence, all the images will have the same color
5831 table. That means that when saved to a file format such as GIF, it will use
5832 that color table as a single common or global color table, for all the images,
5833 without requiring extra local color tables. </p>
5835 <p>Use <a href="command-line-options.html#remap">+remap</a> to reduce all images in the current image
5836 sequence to use a common color map over all the images. This equivalent to
5837 appending all the images together (without extra background colors) and color
5838 reducing those images using <a href="command-line-options.html#colors">-colors</a> with a 256 color
5839 limit, then <a href="command-line-options.html#remap">-remap</a> those colors over the original list of
5840 images. This ensures all the images follow a single color map. </p>
5842 <p>If the number of colors over all the images is less than 256, then <a href="command-line-options.html#remap">+remap</a> should not perform any color reduction or dithering, as
5843 no color changes are needed. In that case, its only effect is to force the use
5844 of a global color table. This recommended after using either <a href="command-line-options.html#colors">-colors</a> or <a href="command-line-options.html#ordered-dither">-ordered-dither</a> to
5845 reduce the number of colors in an animated image sequence. </p>
5847 <p>Note, the remap image colormap has at most 8-bits of precision. Deeper color maps are automagically coalesced with other colors to meet this requirement.</p>
5849 <div style="margin: auto;">
5850 <h4><a id="region"></a>-region <em class="arg">geometry</em></h4>
5853 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set a region in which subsequent operations apply.</td><td style="text-align:right;"></td></tr></table>
5855 <p>The <em class="arg">x</em> and <em class="arg">y</em> offsets are treated
5856 in the same manner as in <a href="command-line-options.html#crop">-crop</a>.</p>
5858 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5860 <div style="margin: auto;">
5861 <h4><a id="remote"></a>-remote</h4>
5864 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">perform a remote operation.</td><td style="text-align:right;"></td></tr></table>
5866 <p>The only command recognized is the name of an image file to load.</p>
5868 <p>If you have more than one <a href="display.html">display</a> application
5869 running simultaneously, use the <a href="command-line-options.html#window"> window</a> option to
5870 specify which application to control.</p>
5872 <div style="margin: auto;">
5873 <h4><a id="render"></a>-render</h4>
5876 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">render vector operations.</td><td style="text-align:right;"></td></tr></table>
5878 <p>Use <a href="command-line-options.html#render">+render</a> to turn off rendering vector operations.
5879 This useful when saving the result to vector formats such as MVG or SVG.</p>
5881 <div style="margin: auto;">
5882 <h4><a id="repage"></a>-repage <em class="arg">geometry</em></h4>
5885 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Adjust the canvas and offset information of the image.</td><td style="text-align:right;"></td></tr></table>
5887 <p>This option is like <a href="command-line-options.html#page">-page</a> but acts as an image operator
5888 rather than a setting. You can separately set the canvas size or the offset
5889 of the image on that canvas by only providing those components. </p>
5891 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5893 <p>If a <code>!</code> flag is given the offset given is added to the existing
5894 offset to move the image relative to its previous position. This useful for
5895 animation sequences. </p>
5897 <p>A given a canvas size of zero such as '<code>0x0</code>' forces it to
5898 recalculate the canvas size so the image (at its current offset) will appear
5899 completely on that canvas (unless it has a negative offset).</p>
5901 <p>Use <a href="command-line-options.html#repage">+repage</a> to completely remove/reset the virtual
5902 canvas meta-data from the images. </p>
5904 <p>The <a href="command-line-options.html#set">-set</a> '<code>page</code>' option can be used to
5905 directly assign virtual canvas meta-data. </p>
5908 <div style="margin: auto;">
5909 <h4><a id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4>
5912 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Resample image to specified horizontal and vertical resolution.</td><td style="text-align:right;"></td></tr></table>
5914 <p>Resize the image so that its rendered size remains the same as the original
5915 at the specified target resolution. For example, if a 300 DPI image renders at
5916 3 inches by 2 inches on a 300 DPI device, when the image has been resampled to
5917 72 DPI, it will render at 3 inches by 2 inches on a 72 DPI device. Note that
5918 only a small number of image formats (e.g. JPEG, PNG, and TIFF) are capable of
5919 storing the image resolution. For formats which do not support an image
5920 resolution, the original resolution of the image must be specified via <a href="command-line-options.html#density">-density</a> on the command line prior to specifying the
5921 resample resolution.</p>
5923 <p>Note that Photoshop stores and obtains image resolution from a proprietary
5924 embedded profile. If this profile exists in the image, then Photoshop will
5925 continue to treat the image using its former resolution, ignoring the image
5926 resolution specified in the standard file header.</p>
5928 <div style="margin: auto;">
5929 <h4><a id="resize"></a>-resize <em class="arg">geometry</em></h4>
5932 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Resize an image.</td><td style="text-align:right;"></td></tr></table>
5934 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are
5935 ignored, and the <a href="command-line-options.html#gravity">-gravity</a> option has no effect.</p>
5937 <p>If the <a href="command-line-options.html#filter">-filter</a> option precedes the <a href="command-line-options.html#resize">-resize</a> option, the image is resized with the specified
5940 <p>Many image processing algorithms assume your image is in a linear-light
5941 coding. If your image is gamma-corrected, you can remove the nonlinear gamma
5942 correction, apply the transform, then restore it like this:</p>
5944 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert portrait.jpg -gamma .45455 -resize 25% -gamma 2.2 \ <br></br> -quality 92 passport.jpg</span></p>
5945 <div style="margin: auto;">
5946 <h4><a id="respect-parentheses"></a>-respect-parentheses</h4>
5949 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">settings remain in effect until parenthesis boundary.</td><td style="text-align:right;"></td></tr></table>
5951 <div style="margin: auto;">
5952 <h4><a id="reverse"></a>-reverse</h4>
5955 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Reverse the order of images in the current image list.</td><td style="text-align:right;"></td></tr></table>
5958 <div style="margin: auto;">
5959 <h4><a id="roll"></a>-roll {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em></h4>
5962 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">roll an image vertically or horizontally by the amount given.</td><td style="text-align:right;"></td></tr></table>
5964 <p>A negative <em class="arg">x</em> offset rolls the image left-to-right.
5965 A negative <em class="arg">y</em> offset rolls the image top-to-bottom.</p>
5968 <div style="margin: auto;">
5969 <h4><a id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4>
5972 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Apply Paeth image rotation (using shear operations) to the image.</td><td style="text-align:right;"></td></tr></table>
5974 <p>Use <code>></code> to rotate the image only if its width exceeds the
5975 height. <code><</code> rotates the image <em>only</em> if its width is less
5976 than the height. For example, if you specify <code>-rotate "-90>"</code> and
5977 the image size is 480x640, the image is not rotated. However, if the image is
5978 640x480, it is rotated by -90 degrees. If you use <code>></code> or
5979 <code><</code>, enclose it in quotation marks to prevent it from being
5980 misinterpreted as a file redirection.</p>
5982 <p>Empty triangles in the corners, left over from rotating the image, are
5983 filled with the <code>background</code> color. </p>
5985 <p>See also the <a href="command-line-options.html#distort">-distort</a> operator and specifically the
5986 '<code>ScaleRotateTranslate</code>' distort method. </p>
5989 <div style="margin: auto;">
5990 <h4><a id="sample"></a>-sample <em class="arg">geometry</em></h4>
5993 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">minify / magnify the image with pixel subsampling and pixel replication, respectively.</td><td style="text-align:right;"></td></tr></table>
5995 <p>Change the image size simply by directly sampling the pixels original
5996 from the image. When magnifying, pixels are replicated in blocks. When
5997 minifying, pixels are sub-sampled (i.e., some rows and columns are skipped
6000 <p>The results are thus equivalent to using <a href="command-line-options.html#resize">-resize</a> with
6001 a <a href="command-line-options.html#filter">-filter</a> setting of <code>point</code> (nearest
6002 neighbour), though <a href="command-line-options.html#sample">-sample</a> is a lot faster, as it
6003 avoids all the filter processing of the image. As such it completely ignores
6004 the current <a href="command-line-options.html#filter">-filter</a> setting. </p>
6006 <p>The key feature of the <a href="command-line-options.html#sample">-sample</a> is that no new colors
6007 will be added to the resulting image, though some colors may disappear. </p>
6009 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are
6010 ignored, unlike <a href="command-line-options.html#resize">-resize</a>. </p>
6013 <p>The actual sampling point is the middle of the sub-region being sampled.
6014 As such a single pixel sampling of an image will take the middle pixel, (or
6015 top-left-middle if image has even dimensions). However the <a href="command-line-options.html#define">-define</a> '<code>sample:offset</code>' can be set to modify
6016 this position some other location within each sub-region being sampled, as
6017 a percentage offset.</p>
6019 <p>By default this value is '<code>50</code>' for the midpoint, but could be set
6020 to '<code>0</code>' for top-left, '<code>100</code>' for bottom-right, or with
6021 separate X and Y offsets such as '<code>0x50</code>' for left-middle edge of
6022 sampling sub-region.</p>
6025 <div style="margin: auto;">
6026 <h4><a id="sampling-factor"></a>-sampling-factor <em class="arg">horizontal-factor</em>x<em class="arg">vertical-factor</em></h4>
6029 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">sampling factors used by JPEG or MPEG-2 encoder and YUV decoder/encoder.</td><td style="text-align:right;"></td></tr></table>
6031 <p>This option specifies the sampling factors to be used by the JPEG encoder
6032 for chroma downsampling. If this option is omitted, the JPEG library will use
6033 its own default values. When reading or writing the YUV format and when
6034 writing the M2V (MPEG-2) format, use <a href="command-line-options.html#sampling-factor">-sampling-factor 2x1</a> or <a href="command-line-options.html#sampling-factor">-sampling-factor 4:2:2</a> to specify the 4:2:2
6035 downsampling method.</p>
6037 <div style="margin: auto;">
6038 <h4><a id="scale"></a>-scale <em class="arg">geometry</em></h4>
6041 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">minify / magnify the image with pixel block averaging and pixel replication, respectively.</td><td style="text-align:right;"></td></tr></table>
6043 <p>Change the image size simply by replacing pixels by averaging pixels
6044 together when minifying, or replacing pixels when magnifying. </p>
6046 <p>The results are thus equivalent to using <a href="command-line-options.html#resize">-resize</a> with
6047 a <a href="command-line-options.html#filter">-filter</a> setting of <code>box</code>. Though it is a lot
6048 faster, as it avoids all the filter processing of the image. As such it
6049 completely ignores the current <a href="command-line-options.html#filter">-filter</a> setting. </p>
6051 <p>If when shrinking (minifying) images the original image is some integer
6052 multiple of the new image size, the number of pixels averaged together to
6053 produce the new pixel color is the same across the whole image. This is
6054 a special case known as 'binning' and is often used as a method of reducing
6055 noise in image such as those generated by digital cameras, especially in low
6056 light conditions. </p>
6059 <div style="margin: auto;">
6060 <h4><a id="scene"></a>-scene <em class="arg">value</em></h4>
6063 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">set scene number.</td><td style="text-align:right;"></td></tr></table>
6065 <p>This option sets the scene number of an image or the first image in an image sequence.</p>
6067 <div style="margin: auto;">
6068 <h4><a id="screen"></a>-screen</h4>
6071 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">specify the screen to capture.</td><td style="text-align:right;"></td></tr></table>
6073 <p>This option indicates that the GetImage request used to obtain the image
6074 should be done on the root window, rather than directly on the specified
6075 window. In this way, you can obtain pieces of other windows that overlap the
6076 specified window, and more importantly, you can capture menus or other popups
6077 that are independent windows but appear over the specified window.</p>
6079 <div style="margin: auto;">
6080 <h4><a id="seed"></a>-seed</h4>
6083 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">seed a new sequence of pseudo-random numbers</td><td style="text-align:right;"></td></tr></table>
6085 <div style="margin: auto;">
6086 <h4><a id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4>
6089 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">segment the colors of an image.</td><td style="text-align:right;"></td></tr></table>
6091 <p>Segment an image by analyzing the histograms of the color components and
6092 identifying units that are homogeneous with the fuzzy c-means technique. This
6093 is part of the ImageMagick color quantization routines. </p>
6095 <p>Specify <em class="arg">cluster threshold</em> as the number of pixels in
6096 each cluster that must exceed the cluster threshold to be considered valid.
6097 <em class="arg">Smoothing threshold</em> eliminates noise in the second
6098 derivative of the histogram. As the value is increased, you can expect
6099 a smoother second derivative. The default is 1.5.</p>
6101 <p>If the <a href="command-line-options.html#verbose">-verbose</a> setting is defined, a detailed report
6102 of the color clusters is returned.</p>
6105 <div style="margin: auto;">
6106 <h4><a id="selective-blur"></a>-selective-blur <em class="arg">radius</em><br></br>-selective-blur <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+threshold</em>}</h4>
6109 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Selectively blur pixels within a contrast threshold.</td><td style="text-align:right;"></td></tr></table>
6111 <p>Blurs those pixels that are less than or equal to the threshold in
6112 contrast. The threshold may be expressed as a fraction of <em class="QR">QuantumRange</em> or as a percentage.</p>
6114 <div style="margin: auto;">
6115 <h4><a id="separate"></a>-separate</h4>
6118 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">separate an image channel into a grayscale image. Specify the channel with <a href="command-line-options.html#channel">-channel</a>.</td><td style="text-align:right;"></td></tr></table>
6120 <div style="margin: auto;">
6121 <h4><a id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4>
6124 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">simulate a sepia-toned photo.</td><td style="text-align:right;"></td></tr></table>
6126 <p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p>
6128 <p>This option applies a special effect to the image, similar to the effect
6129 achieved in a photo darkroom by sepia toning. Threshold ranges from 0 to <em class="QR">QuantumRange</em> and is a measure of the extent of the sepia
6130 toning. A threshold of 80% is a good starting point for a reasonable
6135 <div style="margin: auto;">
6136 <h4><a id="set"></a>-set <em class="arg">key value</em></h4>
6137 <h4>+set <em class="arg">key</em></h4>
6140 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">sets image attributes and properties for images in the current
6141 image sequence.</td><td style="text-align:right;"></td></tr></table>
6143 <p>This will assign (or modify) specific settings attached to all the images
6144 in the current image sequence. Using the <a href="command-line-options.html#set">+set</a> form of the
6145 option will either remove, or reset that setting to a default state, as
6148 <p>For example, it will modify specific well known image meta-data
6149 'attributes' such as those normally overridden by: the options <a href="command-line-options.html#delay">-delay</a>, <a href="command-line-options.html#dispose">-dispose</a>, and <a href="command-line-options.html#page">-page</a>, <a href="command-line-options.html#colorspace">-colorspace</a>; generally
6150 assigned before the image is read in, by using a <em class="arg">key</em> of
6153 <p>If the given <em class="arg">key</em> does not match a specific known
6154 'attribute ', such as shown above, the setting is stored as a a free form
6155 'property' string. Such settings are listed in <a href="command-line-options.html#verbose">-verbose</a> information ("<code>info:</code>" output format) as "Properties".
6158 <p>This includes string 'properties' that are set by and assigned to images
6159 using the options <a href="command-line-options.html#comment">-comment</a>, <a href="command-line-options.html#label">-label</a>, <a href="command-line-options.html#caption">-caption</a>. These options actually assign
6160 a global 'artifact' which are automatically assigned (and any <a href="escape.html">Format Percent
6161 Escapes</a> expanded) to images as they are read in. For example:</p>
6163 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png</span><span class="crtout">identify -format %c rose.png</span><span class="crtprompt"> $ </span><span class="crtin">Rose is a rose is a rose is a rose</span></p>
6164 <p>The set value can also make use of <a href="escape.html">Format and Print Image
6165 Properties</a> in the defined value. For example:</p>
6167 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert rose: -set origsize '%wx%h' -resize 50% \</span><span class="crtout"> -format 'Old size = %[origsize] New size = %wx%h' info:</span><span class="crtprompt"> $ </span><span class="crtin">Old size = 70x46 New size = 35x23</span></p>
6168 <p>Other well known 'properties' that are availible include:
6169 '<code>date:create</code>' and '<code>date:modify</code>' and
6170 '<code>signature</code>'. </p>
6172 <p>The <a href="command-line-options.html#repage">-repage</a> operator will also allow you to modify
6173 the '<code>page</code>' attribute of an image for images already in memory (also
6174 see <a href="command-line-options.html#repage">-page</a>). However it is designed to provide a finer
6175 control of the sub-parts of this 'attribute'. The <a href="command-line-options.html#set">-set page</a>
6176 option will only provide a direct, unmodified assignment of '<code>page</code>'
6179 <p>This option can also associate a colorspace or profile with your image.
6182 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert image.psd -set profile ISOcoated_v2_eci.icc image-icc.psd</span></p>
6183 <p>Some 'properties' must be defined in a specific way to be used. For
6184 example only 'properties' prefixed with "<code>filename:</code>" can be used to
6185 modify the output filename of an image. For example</p>
6187 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png'</span></p>
6188 <p>If the setting value is prefixed with "<code>option:</code>" the setting will
6189 be saved as a global "Artifact" exactly as if it was set using the <a href="command-line-options.html#define">-define</a> option. As such settings are global in scope, they
6190 can be used to pass 'attributes' and 'properties' of one specific image,
6191 in a way that allows you to use them in a completely different image, even if
6192 the original image has long since been modified or destroyed. For example: </p>
6194 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert rose: -set option:rosesize '%wx%h' -delete 0 \</span><span class="crtout"> label:'%[rosesize]' label_size_of_rose.gif</span></p>
6195 <p>Note that <a href="escape.html">Format Percent Escapes</a> will only match
6196 a 'artifact' if the given <em class="arg">key</em> does not match an existing
6197 'attribute' or 'property'. </p>
6199 <p>You can set the attributes of the image registry by prefixing the value
6200 with <code>registry:</code>.</p>
6202 <p>The <a href="command-line-options.html#set">-set profile</a> option can also be used to inject
6203 previously-formatted ancillary chunks into the output PNG file, using
6204 the commandline option as shown below or by setting the profile via a
6205 programming interface:</p>
6207 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert in.png -set profile PNG-chunk-x:<filename> out.png</span></p>
6208 <p>where <em>x</em> is a location flag and
6209 <em class="arg">filename</em> is a file containing the chunk
6210 name in the first 4 bytes, then a colon (":"), followed by the chunk data.
6211 This encoder will compute the chunk length and CRC, so those must not
6212 be included in the file.</p>
6214 <p>"x" can be "b" (before PLTE), "m" (middle, i.e., between PLTE and IDAT),
6215 or "e" (end, i.e., after IDAT). If you want to write multiple chunks
6216 of the same type, then add a short unique string after the "x" to prevent
6217 subsequent profiles from overwriting the preceding ones, e.g.,</p>
6220 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert in.png -set profile PNG-chunk-b01:file01 / <br></br>
6221 -profile PNG-chunk-b02:file02 out.png</span></p>
6223 <div style="margin: auto;">
6224 <h4><a id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4>
6227 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">shade the image using a distant light source.</td><td style="text-align:right;"></td></tr></table>
6229 <p>Specify <em class="arg">azimuth</em> and <em class="arg">elevation</em> as
6230 the position of the light source. Use <a href="command-line-options.html#shade">+shade</a> to return
6231 the shading results as a grayscale image.</p>
6233 <div style="margin: auto;">
6234 <h4><a id="shadow"></a>-shadow <em class="arg">percent-opacity</em>{x<em class="arg">sigma</em>}{<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em>{<em class="arg">%</em>}</h4>
6237 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">simulate an image shadow.</td><td style="text-align:right;"></td></tr></table>
6239 <div style="margin: auto;">
6240 <h4><a id="shared-memory"></a>-shared-memory</h4>
6243 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">use shared memory.</td><td style="text-align:right;"></td></tr></table>
6245 <p>This option specifies whether the utility should attempt to use shared
6246 memory for pixmaps. ImageMagick must be compiled with shared memory support,
6247 and the display must support the <em class="arg">MIT-SHM</em> extension.
6248 Otherwise, this option is ignored. The default is <code>True</code>.</p>
6250 <div style="margin: auto;">
6251 <h4><a id="sharpen"></a>-sharpen <em class="arg">radius</em><br></br>-sharpen <em class="arg">radius</em>x<em class="arg">sigma</em>+<em class="arg">bias</em></h4>
6254 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">sharpen the image.</td><td style="text-align:right;"></td></tr></table>
6256 <p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
6258 <div style="margin: auto;">
6259 <h4><a id="shave"></a>-shave <em class="arg">geometry</em></h4>
6262 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Shave pixels from the image edges.</td><td style="text-align:right;"></td></tr></table>
6264 <p>The <em class="arg">size</em> portion of the <em class="arg">geometry</em>
6265 argument specifies the width of the region to be removed from both sides of
6266 the image and the height of the regions to be removed from top and bottom.
6267 Offsets are ignored.</p>
6269 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6271 <div style="margin: auto;">
6272 <h4><a id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4>
6275 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Shear the image along the x-axis and/or y-axis.</td><td style="text-align:right;"></td></tr></table>
6277 <p>The shear angles may be positive, negative, or zero. When <em class="arg">Ydegrees</em> is omitted it defaults to 0. When both angles are
6278 given, the horizontal component of the shear is performed before the vertical
6281 <p>Shearing slides one edge of an image along the x-axis or y-axis (i.e.,
6282 horizontally or vertically, respectively),creating a parallelogram. The amount
6283 of each is controlled by the respective shear angle. For horizontal shears,
6284 <em class="arg">Xdegrees</em> is measured clockwise relative to "up" (the
6285 negative y-axis), sliding the top edge to the right when 0°<<em class="arg">Xdegrees</em><90° and to the left when 90°<<em class="arg">Xdegrees</em><180°. For vertical shears <em class="arg">Ydegrees</em> is measured clockwise relative to "right" (the
6286 positive x-axis), sliding the right edge down when 0°<<em class="arg">Ydegrees</em><90° and up when 90°<<em class="arg">Ydegrees</em><180°.</p>
6288 <p>Empty triangles left over from shearing the image are filled with the color
6289 defined by the <a href="command-line-options.html#fill">-background</a> option. The color is specified
6290 using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
6292 <p>The horizontal shear is performed before the vertical part. This is
6293 important to note, since horizontal and vertical shears do not
6294 <em>commute</em>, i.e., the order matters in a sequence of shears. For
6295 example, the following two commands are not equivalent.</p>
6297 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert logo: -shear 20x0 -shear 0x60 logo-sheared.png</span><span class="crtout"></span><span class="crtprompt"> $ </span><span class="crtin">convert logo: -shear 0x60 -shear 20x0 logo-sheared.png</span></p>
6298 <p>The first of the two commands above is equivalent to the following, except
6299 for the amount of empty space created; the command that follows generates
6300 a smaller image, and so is a better choice in terms of time and space.</p>
6302 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert logo: -shear 20x60 logo-sheared.png</span></p>
6303 <div style="margin: auto;">
6304 <h4><a id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4>
6307 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">increase the contrast without saturating highlights or shadows.</td><td style="text-align:right;"></td></tr></table>
6309 <p>Increase the contrast of the image using a sigmoidal transfer function
6310 without saturating highlights or shadows. <em class="arg">Contrast</em>
6311 indicates how much to increase the contrast. For example, near 1 is none, 3 is
6312 typical and 20 is a lot. Note that exactly zero is mathematically invalid.
6315 <p>The <em class="arg">mid-point</em> indicates where the maximum change
6316 'slope' in contrast should fall in the resultant image (0 is white; 50% is
6317 middle-gray; 100% is black). </p>
6319 <p>By default the image contrast is increased, use <em class="arg">+sigmoidal-contrast</em> to decrease the contrast.</p>
6321 <p>To achieve the equivalent of a sigmoidal brightness change (similar to
6322 a gamma adjustment), you would use <em class="arg">-sigmoidal-contrast
6323 {brightness}x0%</em> to increase brightness and <em class="arg">+sigmoidal-contrast {brightness}x0%</em> to decrease brightness.
6324 Note the use of '0' fo rthe mid-point of the sigmoidal curve. </p>
6326 <p>Using a very high <em class="arg">contrast</em> will produce a sort of
6327 'smoothed thresholding' of the image. Not as sharp (with high aliasing
6328 effects) of a true threshold, but with tapered gray-levels around the threshold
6329 <em class="arg">mid-point</em>. </p>
6331 <div style="margin: auto;">
6332 <h4><a id="silent"></a>-silent</h4>
6335 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">operate silently.</td><td style="text-align:right;"></td></tr></table>
6337 <div style="margin: auto;">
6338 <h4><a id="similarity-threshold"></a>-similarity-threshold <em class="arg">value</em></h4>
6341 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">minimum RMSE for subimage match.</td><td style="text-align:right;">[<a href="compare.html">compare</a>]</td></tr></table>
6343 <p>If this setting is used, then the search will stop as soon as it finds a match whose metric is less than or equal to the value. A partially filled second output image will result. Using a value of zero, will cause the search to stop at the first perfect match it finds. If this setting is left off, then the search will proceed to completion or as limited by <em class="arg">-dissimilarity-threshold</em>.</p>
6345 <div style="margin: auto;">
6346 <h4><a id="size"></a>-size <em class="arg">width</em>[x<em class="arg">height</em>][<em class="arg">+offset</em>]</h4>
6349 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">set the width and height of the image.</td><td style="text-align:right;"></td></tr></table>
6351 <p>Use this option to specify the width and height of raw images whose
6352 dimensions are unknown such as <code>GRAY</code>, <code>RGB</code>, or
6353 <code>CMYK</code>. In addition to width and height, use <a href="command-line-options.html#size">-size</a> with an offset to skip any header information in the
6354 image or tell the number of colors in a <code>MAP</code> image file, (e.g. -size
6357 <p>For Photo CD images, choose from these sizes:</p>
6367 <div style="margin: auto;">
6368 <h4><a id="sketch"></a>-sketch <em class="arg">radius</em><br></br>-sketch <em class="arg">radius</em>x<em class="arg">sigma</em>+<em class="arg">angle</em></h4>
6371 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">simulate a pencil sketch.</td><td style="text-align:right;"></td></tr></table>
6373 <p>Sketch with the given radius, standard deviation (sigma), and angle. The
6374 angle given is the angle toward which the image is sketched. That is the
6375 direction people would consider the object is coming from. </p>
6377 <div style="margin: auto;">
6378 <h4><a id="smush"></a>-smush <em class="arg">offset</em></h4>
6381 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">smush an image sequence together.</td><td style="text-align:right;"></td></tr></table>
6383 <div style="margin: auto;">
6384 <h4><a id="snaps"></a>-snaps <em class="arg">value</em></h4>
6387 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the number of screen snapshots.</td><td style="text-align:right;">[<a href="import.html">import</a>]</td></tr></table>
6389 <p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
6391 <div style="margin: auto;">
6392 <h4><a id="solarize"></a>-solarize <em class="arg">threshold</em></h4>
6395 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">negate all pixels above the threshold level.</td><td style="text-align:right;"></td></tr></table>
6397 <p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p>
6399 <p>This option produces a <em class="arg">solarization</em> effect seen when
6400 exposing a photographic film to light during the development process.</p>
6402 <div style="margin: auto;">
6403 <h4><a id="sparse-color"></a>-sparse-color <em class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4>
6406 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%"> color the given image using the specified points of color, and filling the other intervening colors using the given methods. </td><td style="text-align:right;"></td></tr></table>
6412 <th align="left" style="width: 8%">Method</th>
6413 <th align="left">Description</th>
6417 <td valign="top">barycentric</td>
6418 <td valign="top">three point triangle of color given 3 points.
6419 Giving only 2 points will form a linear gradient between those points.
6420 The gradient generated extends beyond the triangle created by those
6425 <td valign="top">bilinear</td>
6426 <td valign="top">Like barycentric but for 4 points. Less than 4 points
6427 fall back to barycentric. </td>
6430 <td valign="top">voronoi</td>
6431 <td valign="top">Simply map each pixel to the to nearest color point
6432 given. The result are polygonal 'cells' of solid color. </td>
6436 <td valign="top">shepards</td>
6437 <td valign="top">Colors points biased on the ratio of inverse distance
6438 squared. Generating spots of color in a sea of the average of
6443 <td valign="top">inverse</td>
6444 <td valign="top">Colors points biased on the ratio of inverse distance.
6445 This generates sharper points of color rather than rounded spots of
6446 '<code>shepards</code>' Generating spots of color in a sea of the
6447 average of colors. </td>
6453 <p>The points are placed according to the images location on the virtual
6454 canvas (<a href="command-line-options.html#page">-page</a> or <a href="command-line-options.html#repage">-repage</a>
6455 offset), and do not actually have to exist on the given image, but may be
6456 some point beyond the edge of the image. All points are floating point values.
6459 <p>Only the color channels defined by the <a href="command-line-options.html#channel">-channel</a> are
6460 modified, which means that by default matte/alpha transparency channel is not
6461 effected. Typically transparency channel is turned off either before or after
6464 <p>Of course if some color points are transparent to generate a transparent
6465 gradient, then the image also requires transparency enabled to store the
6468 <p>All the above methods when given a single point of color will replace all
6469 the colors in the image with the color given, regardless of the point. This is
6470 logical, and provides an alternative technique to recolor an image to some
6474 <div style="margin: auto;">
6475 <h4><a id="splice"></a>-splice <em class="arg">geometry</em></h4>
6478 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Splice the current background color into the image.</td><td style="text-align:right;"></td></tr></table>
6480 <p>This will add rows and columns of the current <a href="command-line-options.html#background">-background</a> color into the given image according to the
6481 given <a href="command-line-options.html#gravity">-gravity</a> geometry setting. >See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Essentially <a href="command-line-options.html#splice">-splice</a> will divide the
6482 image into four quadrants, separating them by the inserted rows and columns.
6485 <p>If a dimension of geometry is zero no rows or columns will be added for that
6486 dimension. Similarly using a zero offset with the appropriate <a href="command-line-options.html#gravity">-gravity</a> setting will add rows and columns to the edges of
6487 the image, padding the image only along that one edge. Edge padding is what <a href="command-line-options.html#splice">-splice</a> is most commonly used for. </p>
6489 <p>If the exact same <em class="arg">geometry</em> and <a href="command-line-options.html#gravity">-gravity</a> is later used with <a href="command-line-options.html#chop">-chop</a> the
6490 added added all splices removed. </p>
6492 <div style="margin: auto;">
6493 <h4><a id="spread"></a>-spread <em class="arg">amount</em></h4>
6496 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">displace image pixels by a random amount.</td><td style="text-align:right;"></td></tr></table>
6498 <p>The argument <em class="arg">amount</em> defines the size of the
6499 neighborhood around each pixel from which to choose a candidate pixel to
6502 <div style="margin: auto;">
6503 <h4><a id="statistic"></a>-statistic <em class="arg">type</em> <em class="arg">geometry</em></h4>
6506 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">replace each pixel with corresponding statistic from the neighborhood.</td><td style="text-align:right;">[<a href="convert.html">convert</a>, <a href="mogrify.html">mogrify</a>]</td></tr></table>
6508 <p>Choose from these statistic types:</p>
6510 Gradient maximum difference in area
6511 Maximum maximum value per channel in neighborhood
6512 Minimum minimum value per channel in neighborhood
6513 Mean average value per channel in neighborhood
6514 Median median value per channel in neighborhood
6515 Mode mode (most frequent) value per channel in neighborhood
6516 Nonpeak value just before or after the median value per channel in neighborhood
6519 <div style="margin: auto;">
6520 <h4><a id="stegano"></a>-stegano <em class="arg">offset</em></h4>
6523 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">hide watermark within an image.</td><td style="text-align:right;"></td></tr></table>
6525 <p>Use an offset to start the image hiding some number of pixels from the
6526 beginning of the image. Note this offset and the image size. You will need
6527 this information to recover the steganographic image (e.g. display -size
6528 320x256+35 stegano:image.png).</p>
6530 <div style="margin: auto;">
6531 <h4><a id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4>
6534 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">composite two images to create a red / cyan stereo anaglyph.</td><td style="text-align:right;">[<a href="composite.html">composite</a>]</td></tr></table>
6536 <p>The left side of the stereo pair (second image) is saved as the red channel of the output image. The right side (first image) is saved as the green and blue channels. Red-green stereo glasses are required to properly view the stereo image.</p>
6538 <div style="margin: auto;">
6539 <h4><a id="storage-type"></a>-storage-type <em class="arg">type</em></h4>
6542 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">pixel storage type. Here are the valid types:</td><td style="text-align:right;"></td></tr></table>
6545 char unsigned characters
6550 quantum pixels in the native depth of your ImageMagick distribution
6551 short unsigned shorts
6554 <p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
6555 values range from 0 to the maximum value the storage type can support.</p>
6557 <div style="margin: auto;">
6558 <h4><a id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4>
6561 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set a type of stretch style for fonts.</td><td style="text-align:right;"></td></tr></table>
6563 <p>This setting suggests a type of stretch that ImageMagick should try to
6564 apply to the currently selected font family. Select <em class="arg">fontStretch</em> from the following.</p>
6579 <p>To print a complete list of stretch types, use <a href="command-line-options.html#list">-list
6582 <p>For other settings that affect fonts, see the options <a href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
6584 <div style="margin: auto;">
6585 <h4><a id="strip"></a>-strip</h4>
6588 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">strip the image of any profiles or comments.</td><td style="text-align:right;"></td></tr></table>
6590 <div style="margin: auto;">
6591 <h4><a id="stroke"></a>-stroke <em class="arg">color</em></h4>
6594 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">color to use when stroking a graphic primitive.</td><td style="text-align:right;"></td></tr></table>
6596 <p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
6598 <p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
6600 <div style="margin: auto;">
6601 <h4><a id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4>
6604 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">set the stroke width.</td><td style="text-align:right;"></td></tr></table>
6606 <p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
6608 <div style="margin: auto;">
6609 <h4><a id="style"></a>-style <em class="arg">fontStyle</em></h4>
6612 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set a font style for text.</td><td style="text-align:right;"></td></tr></table>
6614 <p>This setting suggests a font style that ImageMagick should try to apply to
6615 the currently selected font family. Select <em class="arg">fontStyle</em> from
6625 <p>For other settings that affect fonts, see the options <a href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#stretch">-stretch</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
6627 <div style="margin: auto;">
6628 <h4><a id="subimage-search"></a>-subimage-search</h4>
6631 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">search for subimage.</td><td style="text-align:right;">[<a href="compare.html">compare</a>]</td></tr></table>
6633 <p>This option is required to have compare search for the best match location
6634 of a small image within a larger image. This search will produce two images
6635 (or two frames). The first is the "difference" image and the second will
6636 be the "match score" image.</p>
6638 <p>The "match-score" image is smaller containing a pixel for ever possible
6639 position of the top-left corner of the given sub-image. that is its size will
6640 be the size of the larger_image - sub_image + 1. The brightest location in
6641 this image is the location s the locate on the best match that is also
6642 reported. Note that this may or may not be a perfect match, and the actual
6643 brightness will reflect this. Other bright 'peaks' can be used to locate other
6644 possible matching locations. </p>
6646 <p>Note that the search will try to compare the sub-image at every possible
6647 location in the larger image, as such it can be very slow. The smaller the
6648 sub-image the faster this search is. </p>
6651 <div style="margin: auto;">
6652 <h4><a id="swap"></a>-swap <em class="arg">index,index</em></h4>
6655 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Swap the positions of two images in the image sequence.</td><td style="text-align:right;"></td></tr></table>
6657 <p>For example, <a href="command-line-options.html#swap">-swap 0,2</a> swaps the first and the third
6658 images in the current image sequence. Use <a href="command-line-options.html#swap">+swap</a> to switch
6659 the last two images in the sequence.</p>
6661 <div style="margin: auto;">
6662 <h4><a id="swirl"></a>-swirl <em class="arg">degrees</em></h4>
6665 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">swirl image pixels about the center.</td><td style="text-align:right;"></td></tr></table>
6667 <p><em class="arg">Degrees</em> defines the tightness of the swirl.</p>
6669 <div style="margin: auto;">
6670 <h4><a id="synchronize"></a>-synchronize</h4>
6673 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">synchronize image to storage device.</td><td style="text-align:right;"></td></tr></table>
6675 <p>Set to "true" to ensure all image data is fully flushed and synchronized to disk. There is a performance penalty, but the benefit include ensuring a valid image file in the event of a system crash and early reporting if there is not anout disk space for the image pixel cache.</p>
6677 <div style="margin: auto;">
6678 <h4><a id="taint"></a>-taint</h4>
6681 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Mark the image as modified.</td><td style="text-align:right;"></td></tr></table>
6683 <div style="margin: auto;">
6684 <h4><a id="text-font"></a>-text-font <em class="arg">name</em></h4>
6687 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">font for writing fixed-width text.</td><td style="text-align:right;"></td></tr></table>
6689 <p>Specifies the name of the preferred font to use in fixed (typewriter style)
6690 formatted text. The default is 14 point <em class="arg">Courier</em>.</p>
6692 <p>You can tag a font to specify whether it is a PostScript, TrueType, or
6693 OPTION1 font. For example, <code>Courier.ttf</code> is a TrueType font and
6694 <code>x:fixed</code> is OPTION1.</p>
6696 <div style="margin: auto;">
6697 <h4><a id="texture"></a>-texture <em class="arg">filename</em></h4>
6700 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">name of texture to tile onto the image background.</td><td style="text-align:right;"></td></tr></table>
6702 <div style="margin: auto;">
6703 <h4><a id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
6706 <!-- {<em class="arg">green,blue,opacity</em>}
6707 <p>If the green or blue value is omitted, these channels use the same value as
6708 the first one provided. If all three color values are the same, the result is
6709 a bi-level image. If the opacity threshold is omitted, OpaqueOpacity is used
6710 and any partially transparent pixel becomes fully transparent.</p>
6713 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Apply simultaneous black/white threshold to the image.</td><td style="text-align:right;"></td></tr></table>
6715 <p>Any pixel values (more specifically, those channels set using <a href="command-line-options.html#channel">‑channel</a>) that exceed the specified threshold are reassigned the
6716 maximum channel value, while all other values are assigned the minimum.</p>
6718 <p> The threshold value can be given as a percentage or as an absolute integer
6719 value corresponding to the desired channel value. When given as an integer,
6720 the minimum attainable value is 0 (corresponding to black when all channels
6721 are affected), but the maximum value (corresponding to white) is that of the
6722 <code>quantum depth</code> of the particular build of ImageMagick, and is
6723 therefore dependent on the installation. For that reason, a reasonable
6724 recommendation for most applications is to specify the threshold values as
6727 <p> The following would force pixels with red values above 50% to have 100%
6728 red values, while those at or below 50% red would be set to 0 in the red
6729 channel. The green, blue, and alpha channels (if present) would be unchanged.
6732 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert in.png -channel red -threshold 50% out.png</span></p>
6733 <p>As (possibly) impractical but instructive examples, the following would
6734 generate an all-black and an all-white image with the same dimensions as the
6738 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert in.png -threshold 100% black.png</span><span class="crtout"></span><span class="crtprompt"> $ </span><span class="crtin">convert in.png -threshold -1 white.png</span></p>
6739 <p>Note that the values of the transparency channel is treated as 'matte'
6740 values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
6742 <p> See also <a href="command-line-options.html#black-threshold">‑black‑threshold</a> and <a href="command-line-options.html#white-threshold">‑white‑threshold</a>.
6745 <div style="margin: auto;">
6746 <h4><a id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4>
6749 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Create a thumbnail of the image.</td><td style="text-align:right;"></td></tr></table>
6751 <p>This is similar to <a href="command-line-options.html#resize">-resize</a>, except it is optimized
6752 for speed and any image profile, other than a color profile, is removed to
6753 reduce the thumbnail size. To strip the color profiles as well, add <a href="command-line-options.html#strip">-strip</a> just before of after this option.</p>
6755 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6757 <div style="margin: auto;">
6758 <h4><a id="tile"></a>-tile <em class="arg">filename</em></h4>
6761 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the tile image used for filling a subsequent graphic primitive.</td><td style="text-align:right;"></td></tr></table>
6763 <div style="margin: auto;">
6764 <h4>-tile <em class="arg">geometry</em></h4>
6767 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Specify the layout of images .</td><td style="text-align:right;">[<a href="montage.html">montage</a>]</td></tr></table>
6769 <p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6771 <div style="margin: auto;">
6775 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Specifies that a subsequent composite operation is repeated across and down image.</td><td style="text-align:right;">[<a href="composite.html">composite</a>]</td></tr></table>
6777 <div style="margin: auto;">
6778 <h4><a id="tile-offset"></a>-tile-offset {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em></h4>
6781 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Specify the offset for tile images, relative to the background image it is tiled on.</td><td style="text-align:right;"></td></tr></table>
6783 <p>This should be set before the tiling image is set by <a href="command-line-options.html#tile">-tile</a> or <a href="command-line-options.html#texture">-texture</a>, or directly applied for
6784 creating a tiled canvas using <code>TILE:</code> or <code>PATTERN:</code> input
6787 <p>Internally ImageMagick does a <a href="command-line-options.html#roll">-roll</a> of the tile image
6788 by the arguments given when the tile image is set. </p>
6790 <div style="margin: auto;">
6791 <h4><a id="tint"></a>-tint <em class="arg">value</em></h4>
6794 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Tint the image with the fill color.</td><td style="text-align:right;"></td></tr></table>
6796 <p>Tint the image with the fill color.</p>
6798 <p>Specify the amount of tinting as a percentage. Pure colors like black,
6799 white red, yellow, will not be affected by -tint. Only mid-range colors such
6800 as the various shades of grey.</p>
6802 <div style="margin: auto;">
6803 <h4><a id="title"></a>-title <em class="arg">string</em></h4>
6806 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Assign a title to displayed image.</td><td style="text-align:right;">[<a href="animate.html">animate</a>, <a href="display.html">display</a>, <a href="montage.html">montage</a>]</td></tr></table>
6808 <p>Use this option to assign a specific title to the image. This assigned to
6809 the image window and is typically displayed in the window title bar.
6810 Optionally you can include the image filename, type, width, height, Exif data,
6811 or other image attribute by embedding special format characters described
6812 under the <a href="command-line-options.html#format">-format</a> option.</p>
6817 -title "%m:%f %wx%h"
6820 <p>produces an image title of <code>MIFF:bird.miff 512x480</code> for an image
6821 titled <code>bird.miff</code> and whose width is 512 and height is 480.</p>
6824 <div style="margin: auto;">
6825 <h4><a id="transform"></a>-transform</h4>
6828 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">transform the image.</td><td style="text-align:right;"></td></tr></table>
6830 <p>This option applies the transformation matrix from a previous <a href="command-line-options.html#affine">-affine</a> option.</p>
6832 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg</span></p>
6834 <p>This operator has been now been superseded by the <a href="command-line-options.html#distort">-distort</a> '<code>AffineProjection</code>' method. </p>
6837 <div style="margin: auto;">
6838 <h4><a id="transparent"></a>-transparent <em class="arg">color</em></h4>
6841 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Make this color transparent within the image.</td><td style="text-align:right;"></td></tr></table>
6843 <p>The <em class="arg">color</em> argument is defined using the format
6844 described under the <a href="command-line-options.html#fill">-fill</a> option. The <a href="command-line-options.html#fuzz">-fuzz</a> setting can be used to match and replace colors similar to the one
6847 <p>Use <a href="command-line-options.html#transparent">+transparent</a> to invert the pixels matched.
6848 that is make all non-matching colors transparent. </p>
6850 <p>The <a href="command-line-options.html#opaque">-opaque</a> operator is exactly the same as <a href="command-line-options.html#transparent">-transparent</a> but replaces the matching color with the
6851 current <a href="command-line-options.html#fill">-fill</a> color setting, rather than transparent.
6852 However the <a href="command-line-options.html#transparent">-transparent</a> operator also ensures
6853 that the image has an alpha channel enabled, as per "<code><a href="command-line-options.html#alpha">-alpha</a> set</code>", and does not require you to modify the <a href="command-line-options.html#channel">-channel</a> to enable alpha channel handling. </p>
6855 <p>Note that this does not define the color as being the 'transparency color'
6856 used for color-mapped image formats, such as GIF. For that use <a href="command-line-options.html#transparent-color">-transparent-color</a> </p>
6859 <div style="margin: auto;">
6860 <h4><a id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4>
6863 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set the transparent color.</td><td style="text-align:right;"></td></tr></table>
6865 <p>Sometimes this is used for saving to image formats such as
6866 GIF and PNG8 which uses this color to represent boolean transparency. This
6867 does not make a color transparent, it only defines what color the transparent
6868 color is in the color palette of the saved image. Use <a href="command-line-options.html#transparent">-transparent</a> to make an opaque color transparent.</p>
6870 <p>This option allows you to have both an opaque visible color, as well as a
6871 transparent color of the same color value without conflict. That is, you can
6872 use the same color for both the transparent and opaque color areas within an
6873 image. This, in turn, frees to you to select a transparent color that is
6874 appropriate when an image is displayed by an application that does not handle a
6875 transparent color index, while allowing ImageMagick to correctly handle images of this
6878 <p>The default transparent color is <code>#00000000</code>, which is fully transparent black.</p>
6880 <div style="margin: auto;">
6881 <h4><a id="transpose"></a>-transpose</h4>
6884 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Mirror the image along the top-left to bottom-right diagonal.</td><td style="text-align:right;"></td></tr></table>
6886 <p> This option mathematically transposes the pixel array. It is equivalent to the sequence <code>-flip -rotate 90</code>.
6889 <div style="margin: auto;">
6890 <h4><a id="transverse"></a>-transverse</h4>
6893 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Mirror the image along the images bottom-left top-right diagonal. Equivalent to the operations <code>-flop -rotate 90</code>.</td><td style="text-align:right;"></td></tr></table>
6896 <div style="margin: auto;">
6897 <h4><a id="treedepth"></a>-treedepth <em class="arg">value</em></h4>
6900 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">tree depth for the color reduction algorithm.</td><td style="text-align:right;"></td></tr></table>
6902 <p>Normally, this integer value is zero or one. A value of zero or one causes
6903 the use of an optimal tree depth for the color reduction algorithm.</p>
6905 <p>An optimal depth generally allows the best representation of the source
6906 image with the fastest computational speed and the least amount of memory.
6907 However, the default depth is inappropriate for some images. To assure the
6908 best representation, try values between 2 and 8 for this parameter. Refer to
6909 the <a href="quantize.html">color reduction algorithm</a> for more details.</p>
6911 <p>The <a href="command-line-options.html#colors">-colors</a> or <a href="command-line-options.html#monochrome">-monochrome</a>
6912 option, or writing to an image format which requires color reduction, is
6913 required for this option to take effect.</p>
6915 <div style="margin: auto;">
6916 <h4><a id="trim"></a>-trim</h4>
6919 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">trim an image.</td><td style="text-align:right;"></td></tr></table>
6921 <p>This option removes any edges that are exactly the same color as the corner
6922 pixels. Use <a href="command-line-options.html#fuzz">-fuzz</a> to make <a href="command-line-options.html#trim">-trim</a> remove
6923 edges that are nearly the same color as the corner pixels.</p>
6925 <p>The page or virtual canvas information of the image is preserved allowing
6926 you to extract the result of the <a href="command-line-options.html#trim">-trim</a> operation from the
6927 image. Use a <a href="command-line-options.html#repage">+repage</a> to remove the virtual canvas page
6928 information if it is unwanted.</p>
6930 <p>If the trimmed image 'disappears' an warning is produced, and a special
6931 single pixel transparent 'missed' image is returned, in the same way as when a
6932 <a href="command-line-options.html#crop">-crop</a> operation 'misses' the image proper. </p>
6935 <div style="margin: auto;">
6936 <h4><a id="type"></a>-type <em class="arg">type</em></h4>
6939 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">the image type.</td><td style="text-align:right;"></td></tr></table>
6940 <p>Choose from: <code>Bilevel</code>,
6941 <code>Grayscale</code>, <code>GrayscaleMatte</code>, <code>Palette</code>,
6942 <code>PaletteMatte</code>, <code>TrueColor</code>, <code>TrueColorMatte</code>,
6943 <code>ColorSeparation</code>, or <code>ColorSeparationMatte</code>.</p>
6945 <p>Normally, when a format supports different subformats such as grayscale and
6946 truecolor, the encoder will try to choose an efficient subformat. The <a href="command-line-options.html#type">-type</a> option can be used to override this behavior. For
6947 example, to prevent a JPEG from being written in grayscale format even though
6948 only gray pixels are present, use.</p>
6950 <p class="crt"><span class="crtprompt"> $ </span><span class="crtin">convert bird.png -type TrueColor bird.jpg</span></p>
6951 <p>Similarly, use <a href="command-line-options.html#type">-type TrueColorMatte</a> to force the
6952 encoder to write an alpha channel even though the image is opaque, if the
6953 output format supports transparency.</p>
6955 <p>Use <a href="command-line-options.html#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
6957 <div style="margin: auto;">
6958 <h4><a id="undercolor"></a>-undercolor <em class="arg">color</em></h4>
6961 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">set the color of the annotation bounding box.</td><td style="text-align:right;"></td></tr></table>
6963 <p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
6965 <p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
6968 <div style="margin: auto;">
6969 <h4><a id="update"></a>-update <em class="arg">seconds</em></h4>
6972 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">detect when image file is modified and redisplay.</td><td style="text-align:right;"></td></tr></table>
6974 <p>Suppose that while you are displaying an image the file that is currently
6975 displayed is over-written. <code>display</code> will automagically detect that
6976 the input file has been changed and update the displayed image
6980 <div style="margin: auto;">
6981 <h4><a id="unique-colors"></a>-unique-colors</h4>
6984 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">discard all but one of any pixel color.</td><td style="text-align:right;"></td></tr></table>
6987 <div style="margin: auto;">
6988 <h4><a id="units"></a>-units <em class="arg">type</em></h4>
6991 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">the units of image resolution.</td><td style="text-align:right;"></td></tr></table>
6993 <p>Choose from: <code>Undefined</code>, <code>PixelsPerInch</code>, or
6994 <code>PixelsPerCentimeter</code>. This option is normally used in conjunction
6995 with the <a href="command-line-options.html#density">-density</a> option.</p>
6998 <div style="margin: auto;">
6999 <h4><a id="unsharp"></a>-unsharp <em class="arg">radius</em><br></br>-unsharp <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+gain</em>}{<em class="arg">+threshold</em>}</h4>
7002 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">sharpen the image with an unsharp mask operator.</td><td style="text-align:right;"></td></tr></table>
7004 <p>The <a href="command-line-options.html#unsharp">-unsharp</a> option sharpens an image. The image is
7005 convolved with a Gaussian operator of the given radius and standard deviation
7006 (sigma). For reasonable results, radius should be larger than sigma. Use
7007 a radius of 0 to have the method select a suitable radius.</p>
7009 <p>The parameters are:</p>
7012 radius The radius of the Gaussian, in pixels, not counting the center
7014 sigma The standard deviation of the Gaussian, in pixels (default 1.0).
7015 gain The fraction of the difference between the original and the blur
7016 image that is added back into the original (default 1.0).
7017 threshold The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the
7018 difference amount (default 0.05).
7022 <div style="margin: auto;">
7023 <h4><a id="verbose"></a>-verbose</h4>
7026 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">print detailed information about the image when this option
7027 precedes the <a href="command-line-options.html#identify">-identify</a> option or
7028 <code>info:</code>.</td><td style="text-align:right;"></td></tr></table>
7031 <div style="margin: auto;">
7032 <h4><a id="version"></a>-version</h4>
7035 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">print ImageMagick version string and exit.</td><td style="text-align:right;"></td></tr></table>
7038 <div style="margin: auto;">
7039 <h4><a id="view"></a>-view <em class="arg">string</em></h4>
7042 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">FlashPix viewing parameters.</td><td style="text-align:right;"></td></tr></table>
7045 <div style="margin: auto;">
7046 <h4><a id="vignette"></a>-vignette <em class="arg">radius</em>{x<em class="arg">sigma</em>}{<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em>{<em class="arg">%</em>}</h4>
7049 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">soften the edges of the image in vignette style.</td><td style="text-align:right;"></td></tr></table>
7052 <div style="margin: auto;">
7053 <h4><a id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4>
7056 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Specify contents of <em>virtual pixels</em>.</td><td style="text-align:right;"></td></tr></table>
7058 <p>This option defines what color source should be used if and when a color
7059 lookup completely 'misses' the source image. The color(s) that appear to
7060 surround the source image. Generally this color is derived from the source
7061 image, but could also be set to a specify background color. </p>
7063 <p>Choose from these methods:</p>
7066 background the area surrounding the image is the background color
7067 black the area surrounding the image is black
7068 checker-tile alternate squares with image and background color
7069 dither non-random 32x32 dithered pattern
7070 edge extend the edge pixel toward infinity
7071 gray the area surrounding the image is gray
7072 horizontal-tile horizontally tile the image, background color above/below
7073 horizontal-tile-edge horizontally tile the image and replicate the side edge pixels
7074 mirror mirror tile the image
7075 random choose a random pixel from the image
7076 tile tile the image (default)
7077 transparent the area surrounding the image is transparent blackness
7078 vertical-tile vertically tile the image, sides are background color
7079 vertical-tile-edge vertically tile the image and replicate the side edge pixels
7080 white the area surrounding the image is white
7083 <p>The default value is "edge".</p>
7085 <p>This most important for distortion operators such as <a href="command-line-options.html#distort">-distort</a>, <a href="command-line-options.html#implode">-implode</a>, and <a href="command-line-options.html#fx">-fx</a>.
7086 However it also effects operations that may access pixels just outside the
7087 image proper, such as <a href="command-line-options.html#convolve">-convolve</a>, <a href="command-line-options.html#blur">-blur</a>, and <a href="command-line-options.html#sharpen">-sharpen</a>. </p>
7089 <p>To print a complete list of virtual pixel types, use the <a href="command-line-options.html#list">-list virtual-pixel</a> option.</p>
7092 <div style="margin: auto;">
7093 <h4><a id="visual"></a>-visual <em class="arg">type</em></h4>
7096 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Animate images using this X visual type.</td><td style="text-align:right;">[<a href="animate.html">animate</a>, <a href="display.html">display</a>]</td></tr></table>
7098 <p>Choose from these visual classes:</p>
7111 <p>The X server must support the visual you choose, otherwise an error occurs.
7112 If a visual is not specified, the visual class that can display the most
7113 simultaneous colors on the default screen is chosen.</p>
7116 <div style="margin: auto;">
7117 <h4><a id="watermark"></a>-watermark <em class="arg">brightness</em>x<em class="arg">saturation</em></h4>
7120 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Watermark an image using the given percentages of brightness and
7121 saturation.</td><td style="text-align:right;">[<a href="composite.html">composite</a>]</td></tr></table>
7123 <p>Take a grayscale image (with alpha mask) and modify the destination image's
7124 brightness according to watermark image's grayscale value and the <em class="arg">brightness</em> percentage. The destinations color saturation
7125 attribute is just direct modified by the <em class="arg">saturation</em>
7126 percentage, which defaults to 100 percent (no color change). </p>
7129 <div style="margin: auto;">
7130 <h4><a id="wave"></a>-wave <em class="arg">amplitude</em><br></br>-wave <em class="arg">amplitude</em>x<em class="arg">wavelength</em></h4>
7133 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Shear the columns of an image into a sine wave.</td><td style="text-align:right;"></td></tr></table>
7135 <p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em>
7138 <div style="margin: auto;">
7139 <h4><a id="weight"></a>-weight <em class="arg">fontWeight</em></h4>
7142 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Set a font weight for text.</td><td style="text-align:right;"></td></tr></table>
7144 <p>This setting suggests a font weight that ImageMagick should try to apply to
7145 the currently selected font family. Use a positive integer for <em class="arg">fontWeight</em> or select from the following.</p>
7148 <col width="25%"></col>
7149 <col width="75%"></col>
7152 <th><em class="arg">fontWeight</em></th>
7153 <th>Description</th>
7158 <td>No effect. </td></tr>
7160 <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr>
7161 <tr><td>Bolder </td>
7162 <td>Add 100 to font weight if currently ≤ 800.</td></tr>
7163 <tr><td>Lighter </td>
7164 <td>Subtract 100 to font weight if currently ≤ 100.</td></tr>
7165 <tr><td>Normal </td>
7166 <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr>
7170 <p>To print a complete list of weight types, use <a href="command-line-options.html#list">-list
7173 <p>For other settings that affect fonts, see the options <a href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#stretch">-stretch</a>, and <a href="command-line-options.html#style">-style</a>. </p>
7175 <div style="margin: auto;">
7176 <h4><a id="white-point"></a>-white-point <em class="arg">x,y</em></h4>
7179 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">chromaticity white point.</td><td style="text-align:right;"></td></tr></table>
7181 <div style="margin: auto;">
7182 <h4><a id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
7185 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Force to white all pixels above the threshold while leaving all
7186 pixels at or below the threshold unchanged.</td><td style="text-align:right;"></td></tr></table>
7188 <p> The threshold value can be given as a percentage or as an absolute integer
7189 value within [0, <em class="QR">QuantumRange</em>] corresponding to the
7190 desired <a href="command-line-options.html#channel">‑channel</a> value. See <a href="command-line-options.html#threshold">‑threshold</a>for more details on thresholds and resulting values. </p>
7192 <div style="margin: auto;">
7193 <h4><a id="window"></a>-window <em class="arg">id</em></h4>
7196 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">Make the image the background of a window.</td><td style="text-align:right;">[<a href="animate.html">animate</a>, <a href="display.html">display</a>]</td></tr></table>
7198 <p><em class="arg">id</em> can be a window id or name. Specify <code>root</code>
7199 to select X's root window as the target window.</p>
7201 <p>By default the image is tiled onto the background of the target window. If
7202 <code>backdrop</code> or <a href="command-line-options.html#geometry">-resize</a> are specified, the
7203 image is surrounded by the background color. Refer to <code>X RESOURCES</code>
7206 <p>The image will not display on the root window if the image has more unique
7207 colors than the target window colormap allows. Use <a href="command-line-options.html#colors">-colors</a> to reduce the number of colors.</p>
7209 <div style="margin: auto;">
7210 <h4><a id="window-group"></a>-window-group</h4>
7213 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">specify the window group.</td><td style="text-align:right;"></td></tr></table>
7215 <div style="margin: auto;">
7216 <h4><a id="write"></a>-write <em class="arg">filename</em></h4>
7219 <table style="background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%"><tr><td style="width:75%">write an image sequence.</td><td style="text-align:right;"></td></tr></table>
7220 <p>The image sequence preceding the <a href="command-line-options.html#write">-write</a> <em class="arg">filename</em> option is written out, and processing continues with the same image in its current state if there are additional options. To restore the image to its original state after writing it, use the <a href="command-line-options.html#write">+write</a> <em class="arg">filename</em> option.</p>
7222 <p>Use <a href="command-line-options.html#compress">-compress</a> to specify the type of image compression.</p>
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