2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
\r
3 "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
\r
4 <html version="-//W3C//DTD XHTML 1.1//EN"
\r
5 xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"
\r
6 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
\r
7 xsi:schemaLocation="http://www.w3.org/1999/xhtml
\r
8 http://www.w3.org/MarkUp/SCHEMA/xhtml11.xsd">
\r
10 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
\r
11 <meta name="verify-v1" content="g222frIIxcQTrvDR3NBRUSKP3AnMNoqxOkIniCEkV7U="/>
\r
12 <title>ImageMagick: Alpha Compositing</title>
13 <meta http-equiv="Content-Language" content="en-US"/>
14 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
15 <meta http-equiv="Reply-to" content="magick-users@imagemagick.org"/>
16 <meta name="Application-name" content="ImageMagick"/>
17 <meta name="Description" content="Use ImageMagick to convert, edit, or compose bitmap images in a variety of formats. In addition resize, rotate, shear, distort and transform images."/>
18 <meta name="Application-url" content="http://www.imagemagick.org"/>
19 <meta name="Generator" content="PHP"/>
20 <meta name="Keywords" content="alpha, compositing, ImageMagick, ImageMagic, MagickCore, MagickWand, PerlMagick, Magick++, RMagick, PythonMagick, JMagick, TclMagick, Image, Magick, Magic, Wand, ImageMagickObject, Swiss, Army, Knife, Image, Processing"/>
21 <meta name="Rating" content="GENERAL"/>
22 <meta name="Robots" content="INDEX, FOLLOW"/>
23 <meta name="Generator" content="ImageMagick Studio LLC"/>
24 <meta name="Author" content="ImageMagick Studio LLC"/>
25 <meta name="Revisit-after" content="2 DAYS"/>
26 <meta name="Resource-type" content="document"/>
27 <meta name="Copyright" content="Copyright (c) 1999-2011 ImageMagick Studio LLC"/>
28 <meta name="Distribution" content="Global"/>
29 <link rel="icon" href="../images/wand.png"/>
30 <link rel="shortcut icon" href="../images/wand.ico" type="images/x-icon"/>
31 <link rel="meta" type="application/rdf+xml" title="ICI" href="http://imagemagick.org/ici.rdf"/>
\r
32 <link rel="stylesheet" href="http://www.google.com/cse/style/look/default.css" type="text/css" />
\r
33 <style type="text/css" media="all">
\r
34 @import url("../www/magick.css");
\r
36 <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>
\r
37 <script type="text/javascript" src="../fancybox/jquery.fancybox-1.3.4.pack.js"></script>
\r
38 <link rel="stylesheet" type="text/css" href="../fancybox/jquery.fancybox-1.3.4.css" media="screen" />
\r
39 <script type="text/javascript">
\r
40 $(document).ready(function() {
\r
41 $("a[href$=.jpg],a[href$=.png],a[href$=.gif]").fancybox({
\r
42 'transitionIn' : 'elastic',
\r
43 'transitionOut' : 'elastic',
\r
44 'overlayShow' : false,
\r
51 <body id="www-imagemagick-org">
\r
52 <div class="titlebar">
\r
53 <a href="../index.html">
\r
54 <img src="../images/script.png" alt="[ImageMagick]"
\r
55 style="width: 350px; height: 60px; margin: 28px auto; float: left;" /></a>
\r
56 <a href="http://www.networkredux.com">
\r
57 <img src="../images/networkredux.png" alt="[sponsor]"
\r
58 style="margin-top: 42px; border: 0px; float: left;" /></a>
\r
59 <a href="http://www.imagemagick.org/discourse-server/">
\r
60 <img src="../images/logo.jpg"
\r
61 alt="ImageMagick Logo"
\r
62 style="width: 123px; height: 118px; border: 0px; float: right;" /></a>
\r
63 <a href="../index.html">
\r
64 <img src="../images/sprite.jpg"
\r
65 alt="ImageMagick Sprite"
\r
66 style="width: 114px; height: 118px; border: 0px; float: right;" /></a>
\r
69 <div class="westbar">
\r
72 <a title="About ImageMagick" href="../index.html">About ImageMagick</a>
74 <div class="sep"></div>
\r
76 <a title="Binary Releases" href="../www/binary-releases.html">Binary Releases</a>
79 <a title="Binary Release: Unix" href="../www/binary-releases.html#unix">Unix</a>
82 <a title="Binary Release: MacOS X" href="../www/binary-releases.html#macosx">Mac OS X</a>
85 <a title="Binary Release: iPhone" href="../www/binary-releases.html#iPhone">iPhone</a>
88 <a title="Binary Release: Windows" href="../www/binary-releases.html#windows">Windows</a>
90 <div class="sep"></div>
\r
92 <a title="Command-line Tools" href="../www/command-line-tools.html">Command-line Tools</a>
95 <a title="Command-line Tools: Processing" href="../www/command-line-processing.html">Processing</a>
98 <a title="Command-line Tools: Options" href="../www/command-line-options.html">Options</a>
101 <a title="Command-line Tools: Usage" href="http://www.imagemagick.org/Usage/">Usage</a>
104 <a title="Program Interfaces" href="../www/api.html">Program Interfaces</a>
107 <a title="Program Interface: MagickWand" href="../www/magick-wand.html">MagickWand</a>
110 <a title="Program Interface: MagickCore" href="../www/magick-core.html">MagickCore</a>
113 <a title="Program Interface: PerlMagick" href="../www/perl-magick.html">PerlMagick</a>
116 <a title="Program Interface: Magick++" href="../www/magick++.html">Magick++</a>
118 <div class="sep"></div>
\r
120 <a title="Install from Source" href="../www/install-source.html">Install from Source</a>
123 <a title="Install from Source: Unix" href="../www/install-source.html#unix">Unix</a>
126 <a title="Install from Source: Windows" href="../www/install-source.html#windows">Windows</a>
129 <a title="Resources" href="../www/resources.html">Resources</a>
132 <a title="Architecture" href="../www/architecture.html">Architecture</a>
135 <a title="Download" href="../www/download.html">Download</a>
137 <div class="sep"></div>
\r
139 <a title="Search" href="../www/search.html">Search</a>
141 <div class="sep"></div>
\r
143 <a title="Site Map" href="../www/sitemap.html">Site Map</a>
146 <a title="Site Map: Links" href="../www/links.html">Links</a>
148 <div class="sep"></div>
\r
150 <a title="Sponsors" href="../www/sponsors.html">Sponsors:</a>
152 <div class="sponsbox">
153 <div class="sponsor">
154 <a title="Sponsor: Best Web Hosting" href="http://webhostinggeeks.com">Best Web Hosting</a><!-- 201110010720 -->
156 <div class="sponsor">
157 <a title="Sponsor: Web Hosting Ratings" href="http://webhostingrating.com">Web Hosting Ratings</a><!-- 201110010720 -->
159 <div class="sponsor">
160 <a title="Sponsor: Druckerei" href="http://www.allesdruck.de">Druckerei</a><!-- 201107010240 r.leo -->
162 <div class="sponsor">
163 <a title="Sponsor: Web Hosting" href="http://www.bodhost.com/hosting.shtml">Web Hosting</a><!-- 201104010090 -->
165 <div class="sponsor">
166 <a title="Sponsor: Image Converter" href="http://www.batchphoto.com">Image Converter</a><!-- 201103010900 Bits Coffee-->
168 <div class="sponsor">
169 <a title="Sponsor: Flyer drucken" href="http://www.online-druck.biz">Flyer drucken</a><!-- 201109010900 Floeter-->
171 <div class="sponsor">
172 <a title="Sponsor: Druckerei" href="http://print24.com/de/">Druckerei</a><!-- 201110010720 -->
174 <div class="sponsor">
175 <a title="Sponsor: alaTest.com" href="http://alatest.com">alaTest.com</a><!-- 20110801000300 -->
181 <div class="eastbar">
\r
182 <script type="text/javascript">
\r
184 google_ad_client = "pub-3129977114552745";
\r
185 google_ad_slot = "0574824969";
\r
186 google_ad_width = 160;
\r
187 google_ad_height = 600;
\r
190 <script type="text/javascript"
\r
191 src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
\r
197 <h1>ImageMagick Image Composition</h1>
198 <p>This page descibed the Image composition methods that is used to define how
199 two images should be merged together in various image operations. For the
200 Command Line API it is typically set using the <A
201 HREF="../www/command-line-options.html#compose" >-compose</A> setting option. </p>
204 <p>The description of composition uses abstract terminology in order to allow
205 the description to be more precise, while avoiding constant values which are
206 specific to a particular build configuration. Each image pixel is represented
207 by red, green, and blue levels (which are equal for a gray pixel). The
208 build-dependent value <em class="QR">QuantumRange</em> is the maximum integral
209 value which may be stored, per pixel, in the red, green, or blue channels of
210 the image. Each image pixel may also optionally (if the image matte channel is
211 enabled) have an associated level of opacity, ranging from <em>opaque</em> to
212 <em>transparent</em>, which may be used to determine the influence of the pixel
213 color when compositing the pixel with another image pixel. If the image matte
214 channel is disabled, then all pixels in the image are treated as opaque. The
215 color of an opaque pixel is fully visible while the color of a transparent
216 pixel color is entirely absent (pixel color is ignored).</p>
218 <p>By definition, raster images have a rectangular shape. All image rows are of
219 equal length, as are all image columns. By treating the alpha channel as a
220 visual "mask" the rectangular image may be given a "shape" by treating the
221 alpha channel as a cookie-cutter for the image. This is done by setting the
222 pixels within the shape to be opaque, with pixels outside the shape set as
223 transparent. Pixels on the boundary of the shape may be between opaque and
224 transparent in order to provide antialiasing (visually smooth edges). The
225 description of the composition operators use this concept of image "shape" in
226 order to make the description of the operators easier to understand. While it
227 is convenient to describe the operators in terms of "shapes" they are by no
228 means limited to mask-style operations since they are based on continuous
229 floating-point mathematics rather than simple boolean operations.</p>
231 <p>The following alpha blending (Duff-Porter) compose methods are available:</p>
236 <th align="left" style="width: 8%">Method</th>
237 <th align="left">Description</th>
241 <td valign="top">clear</td>
242 <td valign="top">Both the color and the alpha of the destination are
243 cleared. Neither the source nor the destination are used (except for
244 destinations size and other meta-data which is always preserved.</td>
248 <td valign="top">src</td>
249 <td valign="top">The source is copied to the destination. The destination
250 is not used as input, though it is cleared.</td>
254 <td valign="top">dst</td>
255 <td valign="top">The destination is left untouched. The source image is
256 completely ignored.</td>
260 <td valign="top">src-over</td>
261 <td valign="top">The source is composited over the destination. this is
262 the default alpha blending compose method, when neither the compose
263 setting is set, nor is set in the image meta-data.</td>
267 <td valign="top">dst-over</td>
268 <td valign="top">The destination is composited over the source and the
269 result replaces the destination.</td>
273 <td valign="top">src-in</td>
274 <td valign="top">The part of the source lying inside of the destination
275 replaces the destination.</td>
279 <td valign="top">dst-in</td>
280 <td valign="top">The part of the destination lying inside of the source
281 replaces the destination. Areas not overlaid are cleared.</td>
285 <td valign="top">src-out</td>
286 <td valign="top">The part of the source lying outside of the destination
287 replaces the destination.</td>
291 <td valign="top">dst-out</td>
292 <td valign="top">The part of the destination lying outside of the source
293 replaces the destination.</td>
297 <td valign="top">src-atop</td>
298 <td valign="top">The part of the source lying inside of the destination is
299 composited onto the destination.</td>
303 <td valign="top">dst-atop</td>
304 <td valign="top">The part of the destination lying inside of the source is
305 composited over the source and replaces the destination. Areas not
306 overlaid are cleared. </td>
310 <td valign="top">xor</td>
311 <td valign="top">The part of the source that lies outside of the
312 destination is combined with the part of the destination that lies
313 outside of the source. Source or Destination, but not both. </td>
319 <p>Any of the 'Src-*' methods can also be specified without the 'Src-' part.
320 For example the default compose method can be specified as just 'Over'.</p>
322 <p>Many of these compose methods will clear the destination image which was
323 not overlaid by the source image. This is to be expected as part of that
324 specific composition methods defintion. You can disable this by setting the
325 special <A HREF="../www/command-line-options.html#define"
326 >-define</A> 'compose:outside-overlay' to a value of 'false' will turn off
329 <p>On top of the above 12 Duff-Porter Alpha Composition methods, one special
330 related method '<kbd>Copy</kbd>' has been provided. This is equivelent to
331 using the '<kbd>Src</kbd>' with the special <A HREF="../www/command-line-options.html#define"
332 >-define</A> option '<kbd>compose:outside-overlay</kbd>' set to
333 '<kbd>false</kbd>', so as to only modify the overlaid area, without clearing
334 the rest of the image outside the overlaid area. </p>
338 <p>The following mathemathical composition methods are also available. </p>
343 <th align="left" style="width: 8%">Method</th>
344 <th align="left">Description</th>
348 <td valign="top">multiply</td>
349 <td valign="top">The source is multiplied by the destination and replaces
350 the destination. The resultant color is always at least as dark as
351 either of the two constituent colors. Multiplying any color with black
352 produces black. Multiplying any color with white leaves the original
353 color unchanged.</td>
357 <td valign="top">screen</td>
358 <td valign="top">The source and destination are complemented and then
359 multiplied and then replace the destination. The resultant color is
360 always at least as light as either of the two constituent colors.
361 Screening any color with white produces white. Screening any color
362 with black leaves the original color unchanged.</td>
366 <td valign="top">plus</td>
367 <td valign="top">The source is added to the destination and replaces the
368 destination. This operator is useful for averaging or a controled
369 merger of two images, rather than a direct overlay.</td>
373 <td valign="top">add</td>
374 <td valign="top">As per 'plus' but transparency data is treated as matte
375 values. As such any transparent areas in either image remain
380 <td valign="top">minus</td>
381 <td valign="top">Subtract the colors in the source image from the
382 destination image. When transparency is involved, opaque areas is
383 subtracted from any destination opaque areas. </td>
387 <td valign="top">subtract</td>
388 <td valign="top">Subtract the colors in the source image from the
389 destination image. When transparency is involved transparent areas are
390 subtracted, so only the opaque areas in the source remain opaque in
391 the destination image. </td>
395 <td valign="top">difference</td>
396 <td valign="top">Subtracts the darker of the two constituent colors from
397 the lighter. Painting with white inverts the destination color.
398 Painting with black produces no change.</td>
402 <td valign="top">exclusion</td>
403 <td valign="top">Produces an effect similar to that of 'difference', but
404 appears as lower contrast. Painting with white inverts the
405 destination color. Painting with black produces no change.</td>
409 <td valign="top">darken</td>
410 <td valign="top">Selects the darker of the destination and source colors.
411 The destination is replaced with the source when the source is darker,
412 otherwise it is left unchanged.</td>
416 <td valign="top">lighten</td>
417 <td valign="top">Selects the lighter of the destination and source colors.
418 The destination is replaced with the source when the source is
419 lighter, otherwise it is left unchanged. </td>
425 <p>Typically these use the default 'Over' alpha blending when transparencies
426 are also involved, except for 'Plus' which uses a 'plus' alpha blending. This
427 means the alpha channel of both images will only be used to ensure that any
428 visible input remains visible even in parts not overlaid. It also means that
429 any values are weighted by the alpha channel of the input and output images.
430 This 'Over' alpha blending is also applied to the lighting composition methods
433 <p>As of IM v6.6.1-6, if the special '<kbd>Sync</kbd>' flag is not specified
434 (enabled by default) with the <a href="../www/command-line-options.html#channel"
435 >-channel</a> setting, then the above mathematical compositions will nolonger
436 syncronise its actions with the alpha channel. Instead the math composition
437 will be applied on an individual channel basis as defined by the <a
438 href="../www/command-line-options.html#channel"
439 >-channel</a>. This includes the alpha channel. This special usage
440 allows you to perform true mathematics of the image channels, without alpha
441 compostion effects, becomming involved. </p>
443 <p>This special flag is not applied to the lighting composition methods (see
444 below) even though they are closely related to mathematical composition
449 <p>The following lighting composition methods are also available. </p>
454 <th align="left" style="width: 8%">Method</th>
455 <th align="left">Description</th>
459 <td valign="top">linear-dodge</td>
460 <td valign="top">This is equivelent to 'Plus' in that the color channels
461 are simply added, however it does not 'Plus' the alpha channel, but
462 uses the normal 'Over' alpha blending, which transparencies are
463 involved. Produces a sort of additive multiply-like result. Added
464 ImageMagick version 6.5.4-3. </td>
468 <td valign="top">linear-burn</td>
469 <td valign="top">As 'Linear-Dodge', but also subtract one from the result.
470 Sort of a additive 'Screen' of the images. Added ImageMagick version
475 <td valign="top">color-dodge</td>
476 <td valign="top">Brightens the destination color to reflect the source
477 color. Painting with black produces no change.</td>
481 <td valign="top">color-burn</td>
482 <td valign="top">Darkens the destination color to reflect the source
483 color. Painting with white produces no change. Fixed in ImageMagick
484 version 6.5.4-3. </td>
488 <td valign="top">overlay</td>
489 <td valign="top">Multiplies or screens the colors, dependent on the
490 destination color. Source colors overlay the destination whilst
491 preserving its highlights and shadows. The destination color is not
492 replaced, but is mixed with the source color to reflect the lightness
493 or darkness of the destination.</td>
497 <td valign="top">hard-light</td>
498 <td valign="top">Multiplies or screens the colors, dependent on the source
499 color value. If the source color is lighter than 0.5, the destination
500 is lightened as if it were screened. If the source color is darker
501 than 0.5, the destination is darkened, as if it were multiplied. The
502 degree of lightening or darkening is proportional to the difference
503 between the source color and 0.5. If it is equal to 0.5 the
504 destination is unchanged. Painting with pure black or white produces
510 <td valign="top">linear-light</td>
511 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn
512 instead. Increases contrast slightly with an impact on the
513 foreground's tonal values.</td>
517 <td valign="top">soft-light</td>
518 <td valign="top">Darkens or lightens the colors, dependent on the source
519 color value. If the source color is lighter than 0.5, the destination
520 is lightened. If the source color is darker than 0.5, the destination
521 is darkened, as if it were burned in. The degree of darkening or
522 lightening is proportional to the difference between the source color
523 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting
524 with pure black or white produces a distinctly darker or lighter area,
525 but does not result in pure black or white. Fixed in ImageMagick
526 version 6.5.4-3. </td>
530 <td valign="top">pegtop-light</td>
531 <td valign="top">Almost equivelent to 'Soft-Light', but using a
532 continuious mathematical formula rather than two conditionally
533 selected formulae. Added ImageMagick version 6.5.4-3. </td>
537 <td valign="top">vivid-light</td>
538 <td valign="top">A modified 'Linear-Light' designed to preserve very stong
539 primary and secondary colors in the image. Added ImageMagick version
544 <td valign="top">pin-light</td>
545 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings,
546 to similate the effects of a strong 'pinhole' light source. Added
547 ImageMagick version 6.5.4-3. </td>
556 <p>Also included are these special purpose compose methods:</p>
561 <th align="left" style="width: 8%">Method</th>
562 <th align="left">Description</th>
566 <td valign="top">copy</td>
567 <td valign="top">This is equivelent to the Duff-Porter composition method
568 '<kbd>Src,</kbd>' but without clearing the parts of the destination
569 image that is not overlaid. </td>
573 <td valign="top">copy-*</td>
574 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan,
575 Magenta, Yellow, Black, or Opacity) in the source image to the
576 same channel in the destination image. If the channel specified
577 does not exist in the source image, (which can only happen for methods,
578 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is
579 assumed that the source image is a special grayscale channel image
580 of the values that is to be copied. </td>
584 <td valign="top">change-mask</td>
585 <td valign="top">Replace any destination pixel that is the similar to the
586 source images pixel (as defined by the current <a
587 href="../www/command-line-options.html#fuzz">-fuzz</a> factor), with transparency.
595 <p>On top of these composed methods are a few special ones that not only require
596 the two images that are being merged or overlaid, but have some extra numerical
597 arguments, which are tabled below. </p>
599 <p>In the "<code>composite</code>" command these composition methods are
600 selected using special options with the arguments needed. They are usually,
601 but not always, the same name as the composte 'method' they use, and replaces
602 the normal use of the <a href="../www/command-line-options.html#compose" >-compose</a>
603 setting in the "<code>composite</code>" command. For example... </p>
605 <p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>composite ... -blend 50x50 ...</span></p>
606 <p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply
607 these extra arguments to its <a href="../www/command-line-options.html#composite"
608 >-composite</a> operator, using the special <a href="../www/command-line-options.html#define">-define</a>
609 attribute of '<kbd class="arg">compose:args</kbd>'. This means you can now
610 make use of these special argumented <a href="../www/command-line-options.html#compose"
611 >-compose</a> methods, those the argument and the method both need to be set
612 separatally. For example... </p>
614 <p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert ... -compose blend -define compose:args=50,50 -composite ...</span></p>
615 <p>The following is a table of these special 'argumented' compose methods,
616 with a brief summary of what they do. For more details see the equivalent
617 "composite" command option name. </p>
622 <th align="left" style="width: 8%">Method</th>
623 <th align="left">Description</th>
627 <td valign="top">dissolve</td>
628 <td valign="top">Arguments:
629 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
630 <br>Equivalent to "<code>composite</code>" <a href="../www/command-line-options.html#dissolve">-dissolve</a>
631 <br>Dissolve the 'source' image by the percentage given before overlaying
632 'over' the 'destination' image. If <em class="arg">src_percent</em> is
633 greater than 100, it starts dissolving the main image so it will
634 become transparent at a value of '<kbd class="arg">200</kbd>'. If
635 both percentages are given, each image are dissolved to the
641 <td valign="top">blend</td>
642 <td valign="top">Arguments:
643 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
644 <br>Equivalent to "<code>composite</code>" <a
645 href="../www/command-line-options.html#blend">-blend</a>
646 <br>Average the images together ('plus') according to the percentages
647 given and each pixels transparency. If only a single percentage value
648 is given it sets the weight of the composite or 'source' image, while
649 the background image is weighted by the exact opposite amount. That is
650 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of
651 the 'destination' image. Thus it is equivalent to <kbd>-blend
657 <td valign="top">mathematics</td>
658 <td valign="top">Arguments: <em class="arg">A, B, C, D</em>
659 <br>Not available in "<code>composite</code>" at this time.
660 <br>Merge the source and destination images according to the formula
661 <br> <code>A*Sc*Dc + B*Sc + C*Dc + D</code>
662 <br>Can be used to generate a custom composition method that would
663 otherwise need to be implemented using the slow <a
664 href="../www/command-line-options.html#fx">-fx</a> DIY image operator. Added
665 to ImageMagick version 6.5.4-3.
666 <br>As of IM v6.6.1-6 this method will do per-channel math compositions
667 if the 'Sync' flag is removed from <a
668 href="../www/command-line-options.html#channel" >-channel</a>, just like all
669 the other mathematical compostion methods above.
674 <td valign="top">modulate</td>
675 <td valign="top">Arguments:
676 <em class="arg">brightness</em>[x<em class="arg">saturation</em>]
677 <br>Equivalent to "<code>composite</code>" <a href="../www/command-line-options.html#watermark">-watermark</a>
678 <br>Take a grayscale image (with alpha mask) and modify the destination
679 image's brightness according to watermark image's grayscale value and
680 the <em class="arg">brightness</em> percentage. The destinations
681 color saturation attribute is just direct modified by the <em
682 class="arg">saturation</em> percentage, which defaults to 100 percent
689 <td valign="top">displace</td>
690 <td valign="top">Arguments:
691 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%]
692 <br>Equivalent to "<code>composite</code>" <a href="../www/command-line-options.html#displace">-displace</a>
693 <br>With this option, the 'overlay' image, and optionally the 'mask'
694 image, is used as a relative displacement map, which is used to
695 displace the lookup of what part of the destination image is seen at
696 each point of the overlaid area. Much like the displacement map is a
697 'lens' that distorts the original 'background' image behind it.
699 The X-scale is modilated by the 'red' channel of the overlay image
700 while the Y-scale is modulated by the green channel, (the mask image
701 if given is rolled into green channel of the overlay image. This
702 separation allows you to modulate the X and Y lookup displacement
703 separatally allowing you to di 2 dimentional displacements, rather
704 than 1 dimentional verctored displacements (using grayscale image).
706 If the overlay image contains transparency this is used as a mask
707 of the resulting image to remove 'invalid' pixels.
709 The '%' flag makes the displacement scale relative to the size of the
710 overlay image (100% = half width/height of image). Using '!' switches
711 percentage arguments to refer to the destination image size instead.
713 Special flags were added Added to ImageMagick version 6.5.3-5.
718 <td valign="top">distort</td>
719 <td valign="top">Arguments:
720 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em
721 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%]
722 <br>Not available in "<code>composite</code>" at this time.
723 <br>Exactly as per 'Displace' (above), but using absolute coordinates,
724 relative to the center of the overlay (or that given). Basically
725 allows you to generate absolute distortion maps where 'black' will
726 look up the left/top edge, and 'white' looks up the bottom/right
727 edge of the destination image, according to the scale given.
729 The '!' flag not only switches percentage scaling, to use the
730 destination image, but also the image the center offset of the lookup.
731 This means the overlay can lookup a completely different region of the
734 Added to ImageMagick version 6.5.3-5.
739 <td valign="top">blur</td>
740 <td valign="top">Arguments:
741 <em class="arg">Width</em>[x<em class="arg">Height</em
742 >[+<em class="arg">Angle</em>][+<em class="arg">Angle2</em>]]
743 <br>Equivalent to "<code>composite</code>" <a href="../www/command-line-options.html#blur-composite">-blur</a>
744 <br>A Variable Blur Mapping Composition method, where each pixel in the
745 overlaid region is replaced with an Elliptical Weighted Average (EWA),
746 with an ellipse (typically a circle) of the given sigma size, scaled
747 according to overlay (source image) grayscale mapping.
749 As per 'Displace' and 'Distort', the red channel will modulate the
750 width of the ellipse, while the green channel will modulate the height
751 of the ellipse. If a single Angle value is given in the arguments,
752 then the ellipse will then be rotated by the angle specifed.
754 Normally the blue channel of the mapping overlay image is ignored.
755 However if a second ellipse angle is given, then it is assumed that
756 the blue channel defines a variable angle for the ellipse ranging from
757 the first angle to the second angle given. This allows to generate
758 radial blurs, or a rough approximation for rotational blur. Or any mix
761 Added to ImageMagick version 6.5.4-0.
768 <p>To print a complete list of all the available compose operators, use <a
769 href="../www/command-line-options.html#list">-list compose</a>.</p>
776 <span id="linkbar-west"> </span>
\r
777 <span id="linkbar-center">
\r
778 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> •
\r
779 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a>
\r
781 <span id="linkbar-east"> </span>
\r
783 <div class="footer">
\r
784 <span id="footer-west">© 1999-2011 ImageMagick Studio LLC</span>
\r
785 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span>
\r
787 <div style="clear: both; margin: 0; width: 100%; "></div>
\r
788 <script type="text/javascript">
\r
789 var _gaq = _gaq || [];
\r
790 _gaq.push(['_setAccount', 'UA-17690367-1']);
\r
791 _gaq.push(['_trackPageview']);
\r
794 var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
\r
795 ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
\r
796 var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
\r