Gitiles
Code Review Sign In
gerrit-public.fairphone.software / platform / external / ImageMagick / d0083a691be4f20dbc31bc86ee9fda8b9f2b0f40 / . / www / compose.html
blob: 163b0f98d3717d742716c39610fc9828240dbb1c [file] [log] [blame]
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]1
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
3 "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
4<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" dir="ltr">
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]5<head>
6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
7 <meta name="verify-v1" content="g222frIIxcQTrvDR3NBRUSKP3AnMNoqxOkIniCEkV7U="/>
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]8 <title>ImageMagick: Alpha Compositing</title>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]9 <meta http-equiv="Content-Language" content="en-US"/>
10 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
11 <meta http-equiv="Reply-to" content="magick-users@imagemagick.org"/>
12 <meta name="Application-name" content="ImageMagick"/>
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]13 <meta name="Description" content="ImageMagick is a software suite to create, edit, compose, or convert bitmap images in a variety of formats. Use ImageMagick to scale, rotate, shear, distort and transform images."/>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]14 <meta name="Application-url" content="http://www.imagemagick.org"/>
15 <meta name="Generator" content="PHP"/>
16 <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"/>
17 <meta name="Rating" content="GENERAL"/>
18 <meta name="Robots" content="INDEX, FOLLOW"/>
19 <meta name="Generator" content="ImageMagick Studio LLC"/>
20 <meta name="Author" content="ImageMagick Studio LLC"/>
21 <meta name="Revisit-after" content="2 DAYS"/>
22 <meta name="Resource-type" content="document"/>
cristy7e41fe82010-12-04 23:12:08 +0000[diff] [blame]23 <meta name="Copyright" content="Copyright (c) 1999-2011 ImageMagick Studio LLC"/>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]24 <meta name="Distribution" content="Global"/>
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]25 <link rel="icon" href="../images/wand.png"/>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]26 <link rel="shortcut icon" href="../images/wand.ico" type="images/x-icon"/>
27 <link rel="meta" type="application/rdf+xml" title="ICI" href="http://imagemagick.org/ici.rdf"/>
cristy7a40ba82011-01-08 20:31:18 +0000[diff] [blame]28 <link rel="stylesheet" href="http://www.google.com/cse/style/look/default.css" type="text/css" />
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]29 <style type="text/css" media="all">
30 @import url("../www/magick.css");
31 </style>
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]32 <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>
cristy361f4662010-12-31 23:02:52 +0000[diff] [blame]33 <script type="text/javascript" src="../fancybox/jquery.fancybox-1.3.4.pack.js"></script>
34 <link rel="stylesheet" type="text/css" href="../fancybox/jquery.fancybox-1.3.4.css" media="screen" />
35 <script type="text/javascript">
36 $(document).ready(function() {
37 $("a[href$=.jpg],a[href$=.png],a[href$=.gif]").fancybox({
38 'transitionIn' : 'elastic',
39 'transitionOut' : 'elastic',
40 'overlayShow' : false,
41 'opacity' : true
42 });
43 });
44 </script>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]45</head>
46
47<body id="www-imagemagick-org">
48<div class="titlebar">
49<a href="../index.html">
50 <img src="../images/script.png" alt="[ImageMagick]"
51 style="width: 350px; height: 60px; margin: 28px auto; float: left;" /></a>
52<a href="http://www.networkredux.com">
53 <img src="../images/networkredux.png" alt="[sponsor]"
cristy52923442011-01-15 22:54:31 +0000[diff] [blame]54 style="margin-top: 42px; border: 0px; float: left;" /></a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]55<a href="http://www.imagemagick.org/discourse-server/">
56 <img src="../images/logo.jpg" alt=""
cristy178edaf2011-01-23 03:42:39 +0000[diff] [blame]57 style="width: 123px; height: 118px; border: 0px; float: right;" /></a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]58<a href="../index.html">
59 <img src="../images/sprite.jpg" alt=""
60 style="width: 114px; height: 118px; border: 0px; float: right;" /></a>
61</div>
62
63<div class="westbar">
64
65<div class="menu">
66 <a title="About ImageMagick" href="../index.html">About ImageMagick</a>
67</div>
68<div class="sep"></div>
69<div class="menu">
70 <a title="Binary Releases" href="../www/binary-releases.html">Binary Releases</a>
71</div>
72<div class="sub">
73 <a title="Binary Release: Unix" href="../www/binary-releases.html#unix">Unix</a>
74</div>
75<div class="sub">
76 <a title="Binary Release: MacOS X" href="../www/binary-releases.html#macosx">Mac OS X</a>
77</div>
78<div class="sub">
79 <a title="Binary Release: Windows" href="../www/binary-releases.html#windows">Windows</a>
80</div>
81<div class="sep"></div>
82<div class="menu">
83 <a title="Command-line Tools" href="../www/command-line-tools.html">Command-line Tools</a>
84</div>
85<div class="sub">
86 <a title="Command-line Tools: Processing" href="../www/command-line-processing.html">Processing</a>
87</div>
88<div class="sub">
89 <a title="Command-line Tools: Options" href="../www/command-line-options.html">Options</a>
90</div>
91<div class="sub">
92 <a title="Command-line Tools: Usage" href="http://www.imagemagick.org/Usage/">Usage</a>
93</div>
94<div class="menu">
95 <a title="Program Interfaces" href="../www/api.html">Program Interfaces</a>
96</div>
97<div class="sub">
98 <a title="Program Interface: MagickWand" href="../www/magick-wand.html">MagickWand</a>
99</div>
100<div class="sub">
101 <a title="Program Interface: MagickCore" href="../www/magick-core.html">MagickCore</a>
102</div>
103<div class="sub">
104 <a title="Program Interface: PerlMagick" href="../www/perl-magick.html">PerlMagick</a>
105</div>
106<div class="sub">
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]107 <a title="Program Interface: Magick++" href="../www/magick++.html">Magick++</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]108</div>
109<div class="sep"></div>
110<div class="menu">
111 <a title="Install from Source" href="../www/install-source.html">Install from Source</a>
112</div>
113<div class="sub">
114 <a title="Install from Source: Unix" href="../www/install-source.html#unix">Unix</a>
115</div>
116<div class="sub">
117 <a title="Install from Source: Windows" href="../www/install-source.html#windows">Windows</a>
118 </div>
119<div class="menu">
120 <a title="Resources" href="../www/resources.html">Resources</a>
121</div>
122<div class="menu">
123 <a title="Architecture" href="../www/architecture.html">Architecture</a>
124</div>
125<div class="menu">
126 <a title="Download" href="../www/download.html">Download</a>
127</div>
128<div class="sep"></div>
129<div class="menu">
cristy52923442011-01-15 22:54:31 +0000[diff] [blame]130 <a title="Search" href="../www/search.html">Search</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]131</div>
132<div class="sep"></div>
133<div class="menu">
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]134 <a title="Site Map" href="../www/sitemap.html">Site Map</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]135</div>
136<div class="sub">
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]137 <a title="Site Map: Links" href="../www/links.html">Links</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]138</div>
139<div class="sep"></div>
140<div class="menu">
141 <a title="Sponsors" href="../www/sponsors.html">Sponsors:</a>
142
143<div class="sponsbox">
cristy178edaf2011-01-23 03:42:39 +0000[diff] [blame]144<div class="sponsor">
145 <a title="Sponsor: Druckerei" href="http://www.allesdruck.de">Druckerei</a><!-- 201106010240 -->
146</div>
cristyec6b4752011-01-08 03:16:23 +0000[diff] [blame]147<div class="sponsor">
cristy52923442011-01-15 22:54:31 +0000[diff] [blame]148 <a title="Sponsor: Web Hosting" href="http://www.bodhost.com/hosting.shtml">Web Hosting</a><!-- 201104010090 -->
cristy7d52cd62010-10-01 17:26:59 +0000[diff] [blame]149</div>
150<div class="sponsor">
cristyc5baf4f2010-08-31 15:05:33 +0000[diff] [blame]151 <a title="Sponsor: Image Converter" href="http://www.batchphoto.com">Image Converter</a><!-- 201103010900 Bits Coffee-->
152</div>
153<div class="sponsor">
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]154 <a title="Sponsor: Flyer drucken" href="http://www.online-druck.biz">Flyer drucken</a><!-- 201109010900 Floeter-->
155</div>
cristyec6b4752011-01-08 03:16:23 +0000[diff] [blame]156<div class="sponsor">
cristy178edaf2011-01-23 03:42:39 +0000[diff] [blame]157 <a title="Sponsor: Druckerei" href="http://print24.com/de/">Druckerei</a><!-- 201110010720 -->
158</div>
159<div class="sponsor">
160 <a title="Sponsor: alaTest.com" href="http://alatest.com">alaTest.com</a><!-- 20110801000300 -->
cristyec6b4752011-01-08 03:16:23 +0000[diff] [blame]161</div>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]162</div>
163</div>
164</div>
165
166<div class="eastbar">
167 <script type="text/javascript">
168 <!--
169 google_ad_client = "pub-3129977114552745";
170 google_ad_slot = "0574824969";
171 google_ad_width = 160;
172 google_ad_height = 600;
173 //-->
174 </script>
175 <script type="text/javascript"
176 src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
177 </script>
178</div>
179
180<div class="main">
181
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]182<h1>ImageMagick Image Composition</h1>
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]183<p>This page descibed the Image composition methods that is used to define how
184two images should be merged together in various image operations. For the
185Command Line API it is typically set using the <A
186HREF="../www/command-line-options.html#compose" >-compose</A> setting option. </p>
187
188
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]189<p>The description of composition uses abstract terminology in order to allow
190the description to be more precise, while avoiding constant values which are
191specific to a particular build configuration. Each image pixel is represented
192by red, green, and blue levels (which are equal for a gray pixel). The
193build-dependent value <em class="QR">QuantumRange</em> is the maximum integral
194value which may be stored, per pixel, in the red, green, or blue channels of
195the image. Each image pixel may also optionally (if the image matte channel is
196enabled) have an associated level of opacity, ranging from <em>opaque</em> to
197<em>transparent</em>, which may be used to determine the influence of the pixel
198color when compositing the pixel with another image pixel. If the image matte
199channel is disabled, then all pixels in the image are treated as opaque. The
200color of an opaque pixel is fully visible while the color of a transparent
201pixel color is entirely absent (pixel color is ignored).</p>
202
203<p>By definition, raster images have a rectangular shape. All image rows are of
204equal length, as are all image columns. By treating the alpha channel as a
205visual "mask" the rectangular image may be given a "shape" by treating the
206alpha channel as a cookie-cutter for the image. This is done by setting the
207pixels within the shape to be opaque, with pixels outside the shape set as
208transparent. Pixels on the boundary of the shape may be between opaque and
209transparent in order to provide antialiasing (visually smooth edges). The
210description of the composition operators use this concept of image "shape" in
211order to make the description of the operators easier to understand. While it
212is convenient to describe the operators in terms of "shapes" they are by no
213means limited to mask-style operations since they are based on continuous
214floating-point mathematics rather than simple boolean operations.</p>
215
216<p>The following alpha blending (Duff-Porter) compose methods are available:</p>
217
218<table class="doc">
219 <tbody>
220 <tr valign="top">
221 <th align="left" style="width: 8%">Method</th>
222 <th align="left">Description</th>
223 </tr>
224
225 <tr valign="top">
226 <td valign="top">clear</td>
227 <td valign="top">Both the color and the alpha of the destination are
228 cleared. Neither the source nor the destination are used (except for
229 destinations size and other meta-data which is always preserved.</td>
230 </tr>
231
232 <tr valign="top">
233 <td valign="top">src</td>
234 <td valign="top">The source is copied to the destination. The destination
235 is not used as input, though it is cleared.</td>
236 </tr>
237
238 <tr valign="top">
239 <td valign="top">dst</td>
240 <td valign="top">The destination is left untouched. The source image is
241 completely ignored.</td>
242 </tr>
243
244 <tr valign="top">
245 <td valign="top">src-over</td>
246 <td valign="top">The source is composited over the destination. this is
247 the default alpha blending compose method, when neither the compose
248 setting is set, nor is set in the image meta-data.</td>
249 </tr>
250
251 <tr valign="top">
252 <td valign="top">dst-over</td>
253 <td valign="top">The destination is composited over the source and the
254 result replaces the destination.</td>
255 </tr>
256
257 <tr valign="top">
258 <td valign="top">src-in</td>
259 <td valign="top">The part of the source lying inside of the destination
260 replaces the destination.</td>
261 </tr>
262
263 <tr valign="top">
264 <td valign="top">dst-in</td>
265 <td valign="top">The part of the destination lying inside of the source
266 replaces the destination. Areas not overlaid are cleared.</td>
267 </tr>
268
269 <tr valign="top">
270 <td valign="top">src-out</td>
271 <td valign="top">The part of the source lying outside of the destination
272 replaces the destination.</td>
273 </tr>
274
275 <tr valign="top">
276 <td valign="top">dst-out</td>
277 <td valign="top">The part of the destination lying outside of the source
278 replaces the destination.</td>
279 </tr>
280
281 <tr valign="top">
282 <td valign="top">src-atop</td>
283 <td valign="top">The part of the source lying inside of the destination is
284 composited onto the destination.</td>
285 </tr>
286
287 <tr valign="top">
288 <td valign="top">dst-atop</td>
289 <td valign="top">The part of the destination lying inside of the source is
290 composited over the source and replaces the destination. Areas not
291 overlaid are cleared. </td>
292 </tr>
293
294 <tr valign="top">
295 <td valign="top">xor</td>
296 <td valign="top">The part of the source that lies outside of the
297 destination is combined with the part of the destination that lies
298 outside of the source. Source or Destination, but not both. </td>
299 </tr>
300
301 </tbody>
302</table>
303
304<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part.
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]305For example the default compose method can be specified as just 'Over'.</p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]306
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]307<p>Many of these compose methods will clear the destination image which was
308not overlaid by the source image. This is to be expected as part of that
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]309specific composition methods defintion. You can disable this by setting the
310special <A HREF="../www/command-line-options.html#define"
311>-define</A> 'compose:outside-overlay' to a value of 'false' will turn off
312this behaviour. </p>
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]313
314<p>On top of the above 12 Duff-Porter Alpha Composition methods, one special
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]315related method '<kbd>Copy</kbd>' has been provided. This is equivelent to
316using the '<kbd>Src</kbd>' with the special <A HREF="../www/command-line-options.html#define"
317>-define</A> option '<kbd>compose:outside-overlay</kbd>' set to
318'<kbd>false</kbd>', so as to only modify the overlaid area, without clearing
319the rest of the image outside the overlaid area. </p>
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]320
321<br><br>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]322
323<p>The following mathemathical composition methods are also available. </p>
324
325<table class="doc">
326 <tbody>
327 <tr valign="top">
328 <th align="left" style="width: 8%">Method</th>
329 <th align="left">Description</th>
330 </tr>
331
332 <tr valign="top">
333 <td valign="top">multiply</td>
334 <td valign="top">The source is multiplied by the destination and replaces
335 the destination. The resultant color is always at least as dark as
336 either of the two constituent colors. Multiplying any color with black
337 produces black. Multiplying any color with white leaves the original
338 color unchanged.</td>
339 </tr>
340
341 <tr valign="top">
342 <td valign="top">screen</td>
343 <td valign="top">The source and destination are complemented and then
344 multiplied and then replace the destination. The resultant color is
345 always at least as light as either of the two constituent colors.
346 Screening any color with white produces white. Screening any color
347 with black leaves the original color unchanged.</td>
348 </tr>
349
350 <tr valign="top">
351 <td valign="top">plus</td>
352 <td valign="top">The source is added to the destination and replaces the
353 destination. This operator is useful for averaging or a controled
354 merger of two images, rather than a direct overlay.</td>
355 </tr>
356
357 <tr valign="top">
358 <td valign="top">add</td>
359 <td valign="top">As per 'plus' but transparency data is treated as matte
360 values. As such any transparent areas in either image remain
361 transparent. </td>
362 </tr>
363
364 <tr valign="top">
365 <td valign="top">minus</td>
366 <td valign="top">Subtract the colors in the source image from the
367 destination image. When transparency is involved, opaque areas is
368 subtracted from any destination opaque areas. </td>
369 </tr>
370
371 <tr valign="top">
372 <td valign="top">subtract</td>
373 <td valign="top">Subtract the colors in the source image from the
374 destination image. When transparency is involved transparent areas are
375 subtracted, so only the opaque areas in the source remain opaque in
376 the destination image. </td>
377 </tr>
378
379 <tr valign="top">
380 <td valign="top">difference</td>
381 <td valign="top">Subtracts the darker of the two constituent colors from
382 the lighter. Painting with white inverts the destination color.
383 Painting with black produces no change.</td>
384 </tr>
385
386 <tr valign="top">
387 <td valign="top">exclusion</td>
388 <td valign="top">Produces an effect similar to that of 'difference', but
389 appears as lower contrast. Painting with white inverts the
390 destination color. Painting with black produces no change.</td>
391 </tr>
392
393 <tr valign="top">
394 <td valign="top">darken</td>
395 <td valign="top">Selects the darker of the destination and source colors.
396 The destination is replaced with the source when the source is darker,
397 otherwise it is left unchanged.</td>
398 </tr>
399
400 <tr valign="top">
401 <td valign="top">lighten</td>
402 <td valign="top">Selects the lighter of the destination and source colors.
403 The destination is replaced with the source when the source is
404 lighter, otherwise it is left unchanged. </td>
405 </tr>
406
407 </tbody>
408</table>
409
410<p>Typically these use the default 'Over' alpha blending when transparencies
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]411are also involved, except for 'Plus' which uses a 'plus' alpha blending. This
412means the alpha channel of both images will only be used to ensure that any
413visible input remains visible even in parts not overlaid. It also means that
414any values are weighted by the alpha channel of the input and output images.
415This 'Over' alpha blending is also applied to the lighting composition methods
416below. </p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]417
418<p>As of IM v6.6.1-6, if the special '<kbd>Sync</kbd>' flag is not specified
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]419(enabled by default) with the <a href="../www/command-line-options.html#channel"
420>-channel</a> setting, then the above mathematical compositions will nolonger
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]421syncronise its actions with the alpha channel. Instead the math composition
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]422will be applied on an individual channel basis as defined by the <a
423href="../www/command-line-options.html#channel"
424>-channel</a>. This includes the alpha channel. This special usage
425allows you to perform true mathematics of the image channels, without alpha
426compostion effects, becomming involved. </p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]427
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]428<p>This special flag is not applied to the lighting composition methods (see
429below) even though they are closely related to mathematical composition
430methods.</p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]431
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]432<br><br>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]433
434<p>The following lighting composition methods are also available. </p>
435
436<table class="doc">
437 <tbody>
438 <tr valign="top">
439 <th align="left" style="width: 8%">Method</th>
440 <th align="left">Description</th>
441 </tr>
442
443 <tr valign="top">
444 <td valign="top">linear-dodge</td>
445 <td valign="top">This is equivelent to 'Plus' in that the color channels
446 are simply added, however it does not 'Plus' the alpha channel, but
447 uses the normal 'Over' alpha blending, which transparencies are
448 involved. Produces a sort of additive multiply-like result. Added
449 ImageMagick version 6.5.4-3. </td>
450 </tr>
451
452 <tr valign="top">
453 <td valign="top">linear-burn</td>
454 <td valign="top">As 'Linear-Dodge', but also subtract one from the result.
455 Sort of a additive 'Screen' of the images. Added ImageMagick version
456 6.5.4-3. </td>
457 </tr>
458
459 <tr valign="top">
460 <td valign="top">color-dodge</td>
461 <td valign="top">Brightens the destination color to reflect the source
462 color. Painting with black produces no change.</td>
463 </tr>
464
465 <tr valign="top">
466 <td valign="top">color-burn</td>
467 <td valign="top">Darkens the destination color to reflect the source
468 color. Painting with white produces no change. Fixed in ImageMagick
469 version 6.5.4-3. </td>
470 </tr>
471
472 <tr valign="top">
473 <td valign="top">overlay</td>
474 <td valign="top">Multiplies or screens the colors, dependent on the
475 destination color. Source colors overlay the destination whilst
476 preserving its highlights and shadows. The destination color is not
477 replaced, but is mixed with the source color to reflect the lightness
478 or darkness of the destination.</td>
479 </tr>
480
481 <tr valign="top">
482 <td valign="top">hard-light</td>
483 <td valign="top">Multiplies or screens the colors, dependent on the source
484 color value. If the source color is lighter than 0.5, the destination
485 is lightened as if it were screened. If the source color is darker
486 than 0.5, the destination is darkened, as if it were multiplied. The
487 degree of lightening or darkening is proportional to the difference
488 between the source color and 0.5. If it is equal to 0.5 the
489 destination is unchanged. Painting with pure black or white produces
490 black or white.</td>
491 </tr>
492
493
494 <tr valign="top">
495 <td valign="top">linear-light</td>
496 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn
497 instead. Increases contrast slightly with an impact on the
498 foreground's tonal values.</td>
499 </tr>
500
501 <tr valign="top">
502 <td valign="top">soft-light</td>
503 <td valign="top">Darkens or lightens the colors, dependent on the source
504 color value. If the source color is lighter than 0.5, the destination
505 is lightened. If the source color is darker than 0.5, the destination
506 is darkened, as if it were burned in. The degree of darkening or
507 lightening is proportional to the difference between the source color
508 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting
509 with pure black or white produces a distinctly darker or lighter area,
510 but does not result in pure black or white. Fixed in ImageMagick
511 version 6.5.4-3. </td>
512 </tr>
513
514 <tr valign="top">
515 <td valign="top">pegtop-light</td>
516 <td valign="top">Almost equivelent to 'Soft-Light', but using a
517 continuious mathematical formula rather than two conditionally
518 selected formulae. Added ImageMagick version 6.5.4-3. </td>
519 </tr>
520
521 <tr valign="top">
522 <td valign="top">vivid-light</td>
523 <td valign="top">A modified 'Linear-Light' designed to preserve very stong
524 primary and secondary colors in the image. Added ImageMagick version
525 6.5.4-3. </td>
526 </tr>
527
528 <tr valign="top">
529 <td valign="top">pin-light</td>
530 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings,
531 to similate the effects of a strong 'pinhole' light source. Added
532 ImageMagick version 6.5.4-3. </td>
533 </tr>
534
535 </tbody>
536</table>
537
538
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]539<br><br>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]540
541<p>Also included are these special purpose compose methods:</p>
542
543<table class="doc">
544 <tbody>
545 <tr valign="top">
546 <th align="left" style="width: 8%">Method</th>
547 <th align="left">Description</th>
548 </tr>
549
550 <tr valign="top">
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]551 <td valign="top">copy</td>
552 <td valign="top">This is equivelent to the Duff-Porter composition method
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]553 '<kbd>Src,</kbd>' but without clearing the parts of the destination
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]554 image that is not overlaid. </td>
555 </tr>
556
557 <tr valign="top">
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]558 <td valign="top">copy-*</td>
559 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan,
560 Magenta, Yellow, Black, or Opacity) in the source image to the
561 same channel in the destination image. If the channel specified
562 does not exist in the source image, (which can only happen for methods,
563 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is
564 assumed that the source image is a special grayscale channel image
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]565 of the values that is to be copied. </td>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]566 </tr>
567
568 <tr valign="top">
569 <td valign="top">change-mask</td>
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]570 <td valign="top">Replace any destination pixel that is the similar to the
571 source images pixel (as defined by the current <a
572 href="../www/command-line-options.html#fuzz">-fuzz</a> factor), with transparency.
573 </td>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]574 </tr>
575 </tbody>
576</table>
577
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]578<br><br>
579
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]580<p>On top of these composed methods are a few special ones that not only require
581the two images that are being merged or overlaid, but have some extra numerical
582arguments, which are tabled below. </p>
583
584<p>In the "<code>composite</code>" command these composition methods are
585selected using special options with the arguments needed. They are usually,
586but not always, the same name as the composte 'method' they use, and replaces
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]587the normal use of the <a href="../www/command-line-options.html#compose" >-compose</a>
588setting in the "<code>composite</code>" command. For example... </p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]589
590<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>composite ... -blend 50x50 ...</span></p>
591<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]592these extra arguments to its <a href="../www/command-line-options.html#composite"
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]593>-composite</a> operator, using the special <a href="../www/command-line-options.html#define">-define</a>
594attribute of '<kbd class="arg">compose:args</kbd>'. This means you can now
595make use of these special argumented <a href="../www/command-line-options.html#compose"
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]596>-compose</a> methods, those the argument and the method both need to be set
597separatally. For example... </p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]598
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]599<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert ... -compose blend -define compose:args=50,50 -composite ...</span></p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]600<p>The following is a table of these special 'argumented' compose methods,
601with a brief summary of what they do. For more details see the equivalent
602"composite" command option name. </p>
603
604<table class="doc">
605 <tbody>
606 <tr valign="top">
607 <th align="left" style="width: 8%">Method</th>
608 <th align="left">Description</th>
609 </tr>
610
611 <tr valign="top">
612 <td valign="top">dissolve</td>
613 <td valign="top">Arguments:
614 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]615 <br>Equivalent to "<code>composite</code>" <a href="../www/command-line-options.html#dissolve">-dissolve</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]616 <br>Dissolve the 'source' image by the percentage given before overlaying
617 'over' the 'destination' image. If <em class="arg">src_percent</em> is
618 greater than 100, it starts dissolving the main image so it will
619 become transparent at a value of '<kbd class="arg">200</kbd>'. If
620 both percentages are given, each image are dissolved to the
621 percentages given.
622 </td>
623 </tr>
624
625 <tr valign="top">
626 <td valign="top">blend</td>
627 <td valign="top">Arguments:
628 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]629 <br>Equivalent to "<code>composite</code>" <a
630 href="../www/command-line-options.html#blend">-blend</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]631 <br>Average the images together ('plus') according to the percentages
632 given and each pixels transparency. If only a single percentage value
633 is given it sets the weight of the composite or 'source' image, while
634 the background image is weighted by the exact opposite amount. That is
635 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of
636 the 'destination' image. Thus it is equivalent to <kbd>-blend
637 30x70</kbd>.
638 </td>
639 </tr>
640
641 <tr valign="top">
642 <td valign="top">mathematics</td>
643 <td valign="top">Arguments: <em class="arg">A, B, C, D</em>
644 <br>Not available in "<code>composite</code>" at this time.
645 <br>Merge the source and destination images according to the formula
646 <br>&nbsp; &nbsp; &nbsp;<code>A*Sc*Dc + B*Sc + C*Dc + D</code>
647 <br>Can be used to generate a custom composition method that would
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]648 otherwise need to be implemented using the slow <a
649 href="../www/command-line-options.html#fx">-fx</a> DIY image operator. Added
650 to ImageMagick version 6.5.4-3.
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]651 <br>As of IM v6.6.1-6 this method will do per-channel math compositions
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]652 if the 'Sync' flag is removed from <a
653 href="../www/command-line-options.html#channel" >-channel</a>, just like all
654 the other mathematical compostion methods above.
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]655 </td>
656 </tr>
657
658 <tr valign="top">
659 <td valign="top">modulate</td>
660 <td valign="top">Arguments:
661 <em class="arg">brightness</em>[x<em class="arg">saturation</em>]
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]662 <br>Equivalent to "<code>composite</code>" <a href="../www/command-line-options.html#watermark">-watermark</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]663 <br>Take a grayscale image (with alpha mask) and modify the destination
664 image's brightness according to watermark image's grayscale value and
665 the <em class="arg">brightness</em> percentage. The destinations
666 color saturation attribute is just direct modified by the <em
667 class="arg">saturation</em> percentage, which defaults to 100 percent
668 (no color change).
669
670 </td>
671 </tr>
672
673 <tr valign="top">
674 <td valign="top">displace</td>
675 <td valign="top">Arguments:
676 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%]
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]677 <br>Equivalent to "<code>composite</code>" <a href="../www/command-line-options.html#displace">-displace</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]678 <br>With this option, the 'overlay' image, and optionally the 'mask'
679 image, is used as a relative displacement map, which is used to
680 displace the lookup of what part of the destination image is seen at
681 each point of the overlaid area. Much like the displacement map is a
682 'lens' that distorts the original 'background' image behind it.
683 <br><br>
684 The X-scale is modilated by the 'red' channel of the overlay image
685 while the Y-scale is modulated by the green channel, (the mask image
686 if given is rolled into green channel of the overlay image. This
687 separation allows you to modulate the X and Y lookup displacement
688 separatally allowing you to di 2 dimentional displacements, rather
689 than 1 dimentional verctored displacements (using grayscale image).
690 <br><br>
691 If the overlay image contains transparency this is used as a mask
692 of the resulting image to remove 'invalid' pixels.
693 <br><br>
694 The '%' flag makes the displacement scale relative to the size of the
695 overlay image (100% = half width/height of image). Using '!' switches
696 percentage arguments to refer to the destination image size instead.
697 <br><br>
698 Special flags were added Added to ImageMagick version 6.5.3-5.
699 </td>
700 </tr>
701
702 <tr valign="top">
703 <td valign="top">distort</td>
704 <td valign="top">Arguments:
705 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em
706 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%]
707 <br>Not available in "<code>composite</code>" at this time.
708 <br>Exactly as per 'Displace' (above), but using absolute coordinates,
709 relative to the center of the overlay (or that given). Basically
710 allows you to generate absolute distortion maps where 'black' will
711 look up the left/top edge, and 'white' looks up the bottom/right
712 edge of the destination image, according to the scale given.
713 <br><br>
714 The '!' flag not only switches percentage scaling, to use the
715 destination image, but also the image the center offset of the lookup.
716 This means the overlay can lookup a completely different region of the
717 destination image.
718 <br><br>
719 Added to ImageMagick version 6.5.3-5.
720 </td>
721 </tr>
722
723 <tr valign="top">
724 <td valign="top">blur</td>
725 <td valign="top">Arguments:
726 <em class="arg">Width</em>[x<em class="arg">Height</em
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]727 >[+<em class="arg">Angle</em>][+<em class="arg">Angle2</em>]]
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]728 <br>Equivalent to "<code>composite</code>" <a href="../www/command-line-options.html#blur-composite">-blur</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]729 <br>A Variable Blur Mapping Composition method, where each pixel in the
730 overlaid region is replaced with an Elliptical Weighted Average (EWA),
731 with an ellipse (typically a circle) of the given sigma size, scaled
732 according to overlay (source image) grayscale mapping.
733 <br><br>
734 As per 'Displace' and 'Distort', the red channel will modulate the
735 width of the ellipse, while the green channel will modulate the height
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]736 of the ellipse. If a single Angle value is given in the arguments,
737 then the ellipse will then be rotated by the angle specifed.
738 <br><br>
739 Normally the blue channel of the mapping overlay image is ignored.
740 However if a second ellipse angle is given, then it is assumed that
741 the blue channel defines a variable angle for the ellipse ranging from
742 the first angle to the second angle given. This allows to generate
743 radial blurs, or a rough approximation for rotational blur. Or any mix
744 of the two.
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]745 <br><br>
746 Added to ImageMagick version 6.5.4-0.
747 </td>
748 </tr>
749
750 </tbody>
751</table>
752
753<p>To print a complete list of all the available compose operators, use <a
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]754href="../www/command-line-options.html#list">-list compose</a>.</p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]755
756
757
758</div>
759
760<div id="linkbar">
761 <span id="linkbar-west">&nbsp;</span>
762 <span id="linkbar-center">
763 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> &bull;
764 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a>
765 </span>
766 <span id="linkbar-east">&nbsp;</span>
767 </div>
768 <div class="footer">
cristy7e41fe82010-12-04 23:12:08 +0000[diff] [blame]769 <span id="footer-west">&copy; 1999-2011 ImageMagick Studio LLC</span>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]770 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span>
771 </div>
772 <div style="clear: both; margin: 0; width: 100%; "></div>
773 <script type="text/javascript">
774 var _gaq = _gaq || [];
775 _gaq.push(['_setAccount', 'UA-17690367-1']);
776 _gaq.push(['_trackPageview']);
777
778 (function() {
779 var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
780 ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
781 var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
782 })();
783 </script>
784</body>
785</html>