<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE thresholds [
-<!ELEMENT thresholds (threshold)+>
-<!ELEMENT threshold (description , levels)>
-<!ELEMENT description (CDATA)>
-<!ELEMENT levels (CDATA)>
-<!ATTLIST threshold map ID #REQUIRED>
-<!ATTLIST levels width CDATA #REQUIRED>
-<!ATTLIST levels height CDATA #REQUIRED>
-<!ATTLIST levels divisor CDATA #REQUIRED>
+ <!ELEMENT thresholds (threshold)+>
+ <!ATTLIST thresholds xmlns CDATA #FIXED ''>
+ <!ELEMENT threshold (description,levels)>
+ <!ATTLIST threshold xmlns CDATA #FIXED '' alias NMTOKEN #IMPLIED
+ map NMTOKEN #REQUIRED>
+ <!ELEMENT description (#PCDATA)>
+ <!ATTLIST description xmlns CDATA #FIXED ''>
+ <!ELEMENT levels (#PCDATA)>
+ <!ATTLIST levels xmlns CDATA #FIXED '' divisor CDATA #REQUIRED
+ height CDATA #REQUIRED width CDATA #REQUIRED>
]>
<!--
Threshold Maps for Ordered Posterized Dither
Minimal Dither and Non-Dither Threshold Maps
-->
<threshold map="threshold" alias="1x1">
- <description>Threshold Non-Dither</description>
+ <description>Threshold 1x1 (non-dither)</description>
<levels width="1" height="1" divisor="2">
1
</levels>
</threshold>
<threshold map="checks" alias="2x1">
- <description>Checkerboard Dither</description>
+ <description>Checkerboard 2x1 (dither)</description>
<levels width="2" height="2" divisor="3">
1 2
2 1
</threshold>
<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- Dispersed Pixel Ordered Dither Patterns
+ (dispersed) Ordered Dither Patterns
-->
<threshold map="o2x2" alias="2x2">
- <description>Ordered 2x2 Dispersed Pixel</description>
+ <description>Ordered 2x2 (dispersed)</description>
<levels width="2" height="2" divisor="5">
1 3
4 2
</threshold>
<threshold map="o3x3" alias="3x3">
- <description>Ordered 3x3 Dispersed Pixel</description>
+ <description>Ordered 3x3 (dispersed)</description>
<levels width="3" height="3" divisor="10">
3 7 4
6 1 9
From "Dithering Algorithms"
http://www.efg2.com/Lab/Library/ImageProcessing/DHALF.TXT
-->
- <description>Ordered 4x4 Dispersed Pixel</description>
+ <description>Ordered 4x4 (dispersed)</description>
<levels width="4" height="4" divisor="17">
1 9 3 11
13 5 15 7
</levels>
</threshold>
- <threshold map="o5x5bc" alias="5x5">
- <!--
- Added by Glenn Randers-Pehrson, 4 Nov 2010, ImageMagick 6.6.5-6
- -->
- <description>Ordered 5x5 Black Circles</description>
- <levels width="5" height="5" divisor="26">
- 1 21 16 15 4
- 5 17 20 19 14
- 6 21 25 24 12
- 7 18 22 23 11
- 2 8 9 10 3
- </levels>
- </threshold>
-
-
- <threshold map="o5x5wc">
- <!--
- Added by Glenn Randers-Pehrson, 4 Nov 2010, ImageMagick 6.6.5-6
- -->
- <description>Ordered 5x5 White Circles</description>
- <levels width="5" height="5" divisor="26">
- 25 21 10 11 22
- 20 9 6 7 12
- 19 5 1 2 13
- 18 8 4 3 14
- 24 17 16 15 23
- </levels>
- </threshold>
-
- <threshold map="o6x6bc" alias="6x6">
- <!--
- Added by Glenn Randers-Pehrson, 4 Nov 2010, ImageMagick 6.6.5-6
- -->
- <description>Ordered 6x6 Black Circles</description>
- <levels width="6" height="6" divisor="37">
- 1 5 14 13 12 4
- 6 22 28 27 21 11
- 15 29 35 34 26 20
- 16 30 36 33 25 19
- 7 23 31 32 24 10
- 2 8 17 18 9 3
- </levels>
- </threshold>
-
- <threshold map="o6x6wc">
- <!--
- Added by Glenn Randers-Pehrson, 4 Nov 2010, ImageMagick 6.6.5-6
- -->
- <description>Ordered 6x6 White Circles</description>
- <levels width="6" height="6" divisor="37">
- 36 32 23 24 25 33
- 31 15 9 10 16 26
- 22 8 2 3 11 17
- 21 7 1 4 12 18
- 30 14 6 5 13 27
- 35 29 20 19 28 34
- </levels>
- </threshold>
-
- <threshold map="o7x7bc" alias="7x7">
- <!--
- Added by Glenn Randers-Pehrson, 4 Nov 2010, ImageMagick 6.6.5-6
- -->
- <description>Ordered 7x7 Black Circles</description>
- <levels width="7" height="7" divisor="50">
- 2 7 17 26 15 6 1
- 8 16 33 39 32 13 5
- 18 34 44 48 43 31 14
- 27 40 45 49 47 38 25
- 20 35 41 46 42 30 24
- 9 19 36 37 29 22 12
- 3 10 21 28 23 11 4
- </levels>
- </threshold>
-
-
- <threshold map="o7x7wc">
- <!--
- Added by Glenn Randers-Pehrson, 4 Nov 2010, ImageMagick 6.6.5-6
- -->
- <description>Ordered 7x7 White Circles</description>
- <levels width="7" height="7" divisor="50">
- 49 42 32 18 19 33 48
- 41 31 17 10 11 20 34
- 40 30 9 2 3 12 21
- 39 29 8 1 4 5 22
- 43 28 16 7 6 13 23
- 44 38 27 15 14 24 35
- 46 45 37 26 25 36 47
- </levels>
- </threshold>
-
-
<threshold map="o8x8" alias="8x8">
<!-- Extracted from original 'OrderedDither()' Function -->
- <description>Ordered 8x8 Dispersed Pixel</description>
+ <description>Ordered 8x8 (dispersed)</description>
<levels width="8" height="8" divisor="65">
1 49 13 61 4 52 16 64
33 17 45 29 36 20 48 32
Halftones - Angled 45 degrees
Initially added to ImageMagick by Glenn Randers-Pehrson, IM v6.2.8-6,
- modified to be more halftone-like by Anthony, IM v6.2.9-7 Larger halftone
- patterns still needed to be added.
+ modified to be more symmetrical with intensity by Anthony, IM v6.2.9-7
+
+ These patterns initially start as circles, but then form diamonds
+ pattern at the 50% threshold level, before forming negated circles,
+ as it approached the other threshold extereme.
-->
<threshold map="h4x4a" alias="4x1">
<description>Halftone 4x4 (angled)</description>
Initially added by Anthony Thyssen, IM v6.2.9-5 using techniques from
"Dithering & Halftoning" by Gernot Haffmann
http://www.fho-emden.de/~hoffmann/hilb010101.pdf
+
+ These patterns initially start as circles, but then form square
+ pattern at the 50% threshold level, before forming negated circles,
+ as it approached the other threshold extereme.
-->
<threshold map="h4x4o">
<description>Halftone 4x4 (orthogonal)</description>
</levels>
</threshold>
+<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ Halftones - Orthogonally Expanding Circle Patterns
+
+ Added by Glenn Randers-Pehrson, 4 Nov 2010, ImageMagick 6.6.5-6
+
+ Rather than producing a diamond 50% threshold pattern, these
+ continue to generate larger (overlapping) circles. They are
+ more like a true halftone pattern formed by covering a surface
+ with either pure white or pure black circular dots.
+
+ WARNING: true halftone patterns only use true circles even in
+ areas of highly varying intensity. Threshold dither patterns
+ can generate distorted circles in such areas.
+-->
+
+ <threshold map="c5x5b" alias="c5x5">
+ <description>Circles 5x5 (black)</description>
+ <levels width="5" height="5" divisor="26">
+ 1 21 16 15 4
+ 5 17 20 19 14
+ 6 21 25 24 12
+ 7 18 22 23 11
+ 2 8 9 10 3
+ </levels>
+ </threshold>
+
+
+ <threshold map="c5x5w">
+ <description>Circles 5x5 (white)</description>
+ <levels width="5" height="5" divisor="26">
+ 25 21 10 11 22
+ 20 9 6 7 12
+ 19 5 1 2 13
+ 18 8 4 3 14
+ 24 17 16 15 23
+ </levels>
+ </threshold>
+
+ <threshold map="c6x6b" alias="c6x6">
+ <description>Circles 6x6 (black)</description>
+ <levels width="6" height="6" divisor="37">
+ 1 5 14 13 12 4
+ 6 22 28 27 21 11
+ 15 29 35 34 26 20
+ 16 30 36 33 25 19
+ 7 23 31 32 24 10
+ 2 8 17 18 9 3
+ </levels>
+ </threshold>
+
+ <threshold map="c6x6w">
+ <description>Circles 6x6 (white)</description>
+ <levels width="6" height="6" divisor="37">
+ 36 32 23 24 25 33
+ 31 15 9 10 16 26
+ 22 8 2 3 11 17
+ 21 7 1 4 12 18
+ 30 14 6 5 13 27
+ 35 29 20 19 28 34
+ </levels>
+ </threshold>
+
+ <threshold map="c7x7b" alias="c7x7">
+ <description>Circles 7x7 (black)</description>
+ <levels width="7" height="7" divisor="50">
+ 3 9 18 28 17 8 2
+ 10 24 33 39 32 23 7
+ 19 34 44 48 43 31 16
+ 25 40 45 49 47 38 27
+ 20 35 41 46 42 29 15
+ 11 21 36 37 28 22 6
+ 4 12 13 26 14 5 1
+ </levels>
+ </threshold>
+
+
+ <threshold map="c7x7w">
+ <description>Circles 7x7 (white)</description>
+ <levels width="7" height="7" divisor="50">
+ 47 41 32 22 33 42 48
+ 40 26 17 11 18 27 43
+ 31 16 6 2 7 19 34
+ 25 10 5 1 3 12 23
+ 30 15 9 4 8 20 35
+ 39 29 14 13 21 28 44
+ 46 38 37 24 36 45 49
+ </levels>
+ </threshold>
+
+
<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Special Purpose Dithers
-->
projects / imagemagick / blobdiff