Gitiles
Code Review Sign In
gerrit-public.fairphone.software / platform / external / ImageMagick / 7363fdec3d60ce2a051a6d363a95d0634002e6e7 / . / www / compose.html
blob: 29809c5b229a5d060329b5aa7b6d46407f1c4d5e [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"/>
cristyaf8d6652011-02-04 21:57:45 +0000[diff] [blame]13 <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."/>
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/">
cristyaf8d6652011-02-04 21:57:45 +0000[diff] [blame]56 <img src="../images/logo.jpg"
57 alt="ImageMagick Logo"
cristy178edaf2011-01-23 03:42:39 +0000[diff] [blame]58 style="width: 123px; height: 118px; border: 0px; float: right;" /></a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]59<a href="../index.html">
cristyaf8d6652011-02-04 21:57:45 +0000[diff] [blame]60 <img src="../images/sprite.jpg"
61 alt="ImageMagick Sprite"
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]62 style="width: 114px; height: 118px; border: 0px; float: right;" /></a>
63</div>
64
65<div class="westbar">
66
67<div class="menu">
68 <a title="About ImageMagick" href="../index.html">About ImageMagick</a>
69</div>
70<div class="sep"></div>
71<div class="menu">
72 <a title="Binary Releases" href="../www/binary-releases.html">Binary Releases</a>
73</div>
74<div class="sub">
75 <a title="Binary Release: Unix" href="../www/binary-releases.html#unix">Unix</a>
76</div>
77<div class="sub">
78 <a title="Binary Release: MacOS X" href="../www/binary-releases.html#macosx">Mac OS X</a>
79</div>
80<div class="sub">
81 <a title="Binary Release: Windows" href="../www/binary-releases.html#windows">Windows</a>
82</div>
83<div class="sep"></div>
84<div class="menu">
85 <a title="Command-line Tools" href="../www/command-line-tools.html">Command-line Tools</a>
86</div>
87<div class="sub">
88 <a title="Command-line Tools: Processing" href="../www/command-line-processing.html">Processing</a>
89</div>
90<div class="sub">
91 <a title="Command-line Tools: Options" href="../www/command-line-options.html">Options</a>
92</div>
93<div class="sub">
94 <a title="Command-line Tools: Usage" href="http://www.imagemagick.org/Usage/">Usage</a>
95</div>
96<div class="menu">
97 <a title="Program Interfaces" href="../www/api.html">Program Interfaces</a>
98</div>
99<div class="sub">
100 <a title="Program Interface: MagickWand" href="../www/magick-wand.html">MagickWand</a>
101</div>
102<div class="sub">
103 <a title="Program Interface: MagickCore" href="../www/magick-core.html">MagickCore</a>
104</div>
105<div class="sub">
106 <a title="Program Interface: PerlMagick" href="../www/perl-magick.html">PerlMagick</a>
107</div>
108<div class="sub">
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]109 <a title="Program Interface: Magick++" href="../www/magick++.html">Magick++</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]110</div>
111<div class="sep"></div>
112<div class="menu">
113 <a title="Install from Source" href="../www/install-source.html">Install from Source</a>
114</div>
115<div class="sub">
116 <a title="Install from Source: Unix" href="../www/install-source.html#unix">Unix</a>
117</div>
118<div class="sub">
119 <a title="Install from Source: Windows" href="../www/install-source.html#windows">Windows</a>
120 </div>
121<div class="menu">
122 <a title="Resources" href="../www/resources.html">Resources</a>
123</div>
124<div class="menu">
125 <a title="Architecture" href="../www/architecture.html">Architecture</a>
126</div>
127<div class="menu">
128 <a title="Download" href="../www/download.html">Download</a>
129</div>
130<div class="sep"></div>
131<div class="menu">
cristy52923442011-01-15 22:54:31 +0000[diff] [blame]132 <a title="Search" href="../www/search.html">Search</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]133</div>
134<div class="sep"></div>
135<div class="menu">
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]136 <a title="Site Map" href="../www/sitemap.html">Site Map</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]137</div>
138<div class="sub">
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]139 <a title="Site Map: Links" href="../www/links.html">Links</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]140</div>
141<div class="sep"></div>
142<div class="menu">
143 <a title="Sponsors" href="../www/sponsors.html">Sponsors:</a>
144
145<div class="sponsbox">
cristy178edaf2011-01-23 03:42:39 +0000[diff] [blame]146<div class="sponsor">
cristyaf8d6652011-02-04 21:57:45 +0000[diff] [blame]147 <a title="Sponsor: Best Web Hosting" href="http://webhostinggeeks.com">Best Web Hosting</a><!-- 201110010720 -->
148</div>
149<div class="sponsor">
150 <a title="Sponsor: Web Hosting Ratings" href="http://webhostingrating.com">Web Hosting Ratings</a><!-- 201110010720 -->
151</div>
152<div class="sponsor">
cristy178edaf2011-01-23 03:42:39 +0000[diff] [blame]153 <a title="Sponsor: Druckerei" href="http://www.allesdruck.de">Druckerei</a><!-- 201106010240 -->
154</div>
cristyec6b4752011-01-08 03:16:23 +0000[diff] [blame]155<div class="sponsor">
cristy52923442011-01-15 22:54:31 +0000[diff] [blame]156 <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]157</div>
158<div class="sponsor">
cristyc5baf4f2010-08-31 15:05:33 +0000[diff] [blame]159 <a title="Sponsor: Image Converter" href="http://www.batchphoto.com">Image Converter</a><!-- 201103010900 Bits Coffee-->
160</div>
161<div class="sponsor">
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]162 <a title="Sponsor: Flyer drucken" href="http://www.online-druck.biz">Flyer drucken</a><!-- 201109010900 Floeter-->
163</div>
cristyec6b4752011-01-08 03:16:23 +0000[diff] [blame]164<div class="sponsor">
cristy178edaf2011-01-23 03:42:39 +0000[diff] [blame]165 <a title="Sponsor: Druckerei" href="http://print24.com/de/">Druckerei</a><!-- 201110010720 -->
166</div>
167<div class="sponsor">
cristya3c43262011-02-13 16:50:35 +0000[diff] [blame]168 <a title="Sponsor: Fernsehdienst Berlin" href="http://www.atlas-multimedia.de">Fernsehdienst Berlin</a><!-- 2011050100025 atlas.multimedia-->
cristyec6b4752011-01-08 03:16:23 +0000[diff] [blame]169</div>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]170</div>
171</div>
172</div>
173
174<div class="eastbar">
175 <script type="text/javascript">
176 <!--
177 google_ad_client = "pub-3129977114552745";
178 google_ad_slot = "0574824969";
179 google_ad_width = 160;
180 google_ad_height = 600;
181 //-->
182 </script>
183 <script type="text/javascript"
184 src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
185 </script>
186</div>
187
188<div class="main">
189
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]190<h1>ImageMagick Image Composition</h1>
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]191<p>This page descibed the Image composition methods that is used to define how
192two images should be merged together in various image operations. For the
193Command Line API it is typically set using the <A
194HREF="../www/command-line-options.html#compose" >-compose</A> setting option. </p>
195
196
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]197<p>The description of composition uses abstract terminology in order to allow
198the description to be more precise, while avoiding constant values which are
199specific to a particular build configuration. Each image pixel is represented
200by red, green, and blue levels (which are equal for a gray pixel). The
201build-dependent value <em class="QR">QuantumRange</em> is the maximum integral
202value which may be stored, per pixel, in the red, green, or blue channels of
203the image. Each image pixel may also optionally (if the image matte channel is
204enabled) have an associated level of opacity, ranging from <em>opaque</em> to
205<em>transparent</em>, which may be used to determine the influence of the pixel
206color when compositing the pixel with another image pixel. If the image matte
207channel is disabled, then all pixels in the image are treated as opaque. The
208color of an opaque pixel is fully visible while the color of a transparent
209pixel color is entirely absent (pixel color is ignored).</p>
210
211<p>By definition, raster images have a rectangular shape. All image rows are of
212equal length, as are all image columns. By treating the alpha channel as a
213visual "mask" the rectangular image may be given a "shape" by treating the
214alpha channel as a cookie-cutter for the image. This is done by setting the
215pixels within the shape to be opaque, with pixels outside the shape set as
216transparent. Pixels on the boundary of the shape may be between opaque and
217transparent in order to provide antialiasing (visually smooth edges). The
218description of the composition operators use this concept of image "shape" in
219order to make the description of the operators easier to understand. While it
220is convenient to describe the operators in terms of "shapes" they are by no
221means limited to mask-style operations since they are based on continuous
222floating-point mathematics rather than simple boolean operations.</p>
223
224<p>The following alpha blending (Duff-Porter) compose methods are available:</p>
225
226<table class="doc">
227 <tbody>
228 <tr valign="top">
229 <th align="left" style="width: 8%">Method</th>
230 <th align="left">Description</th>
231 </tr>
232
233 <tr valign="top">
234 <td valign="top">clear</td>
235 <td valign="top">Both the color and the alpha of the destination are
236 cleared. Neither the source nor the destination are used (except for
237 destinations size and other meta-data which is always preserved.</td>
238 </tr>
239
240 <tr valign="top">
241 <td valign="top">src</td>
242 <td valign="top">The source is copied to the destination. The destination
243 is not used as input, though it is cleared.</td>
244 </tr>
245
246 <tr valign="top">
247 <td valign="top">dst</td>
248 <td valign="top">The destination is left untouched. The source image is
249 completely ignored.</td>
250 </tr>
251
252 <tr valign="top">
253 <td valign="top">src-over</td>
254 <td valign="top">The source is composited over the destination. this is
255 the default alpha blending compose method, when neither the compose
256 setting is set, nor is set in the image meta-data.</td>
257 </tr>
258
259 <tr valign="top">
260 <td valign="top">dst-over</td>
261 <td valign="top">The destination is composited over the source and the
262 result replaces the destination.</td>
263 </tr>
264
265 <tr valign="top">
266 <td valign="top">src-in</td>
267 <td valign="top">The part of the source lying inside of the destination
268 replaces the destination.</td>
269 </tr>
270
271 <tr valign="top">
272 <td valign="top">dst-in</td>
273 <td valign="top">The part of the destination lying inside of the source
274 replaces the destination. Areas not overlaid are cleared.</td>
275 </tr>
276
277 <tr valign="top">
278 <td valign="top">src-out</td>
279 <td valign="top">The part of the source lying outside of the destination
280 replaces the destination.</td>
281 </tr>
282
283 <tr valign="top">
284 <td valign="top">dst-out</td>
285 <td valign="top">The part of the destination lying outside of the source
286 replaces the destination.</td>
287 </tr>
288
289 <tr valign="top">
290 <td valign="top">src-atop</td>
291 <td valign="top">The part of the source lying inside of the destination is
292 composited onto the destination.</td>
293 </tr>
294
295 <tr valign="top">
296 <td valign="top">dst-atop</td>
297 <td valign="top">The part of the destination lying inside of the source is
298 composited over the source and replaces the destination. Areas not
299 overlaid are cleared. </td>
300 </tr>
301
302 <tr valign="top">
303 <td valign="top">xor</td>
304 <td valign="top">The part of the source that lies outside of the
305 destination is combined with the part of the destination that lies
306 outside of the source. Source or Destination, but not both. </td>
307 </tr>
308
309 </tbody>
310</table>
311
312<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part.
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]313For example the default compose method can be specified as just 'Over'.</p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]314
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]315<p>Many of these compose methods will clear the destination image which was
316not overlaid by the source image. This is to be expected as part of that
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]317specific composition methods defintion. You can disable this by setting the
318special <A HREF="../www/command-line-options.html#define"
319>-define</A> 'compose:outside-overlay' to a value of 'false' will turn off
320this behaviour. </p>
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]321
322<p>On top of the above 12 Duff-Porter Alpha Composition methods, one special
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]323related method '<kbd>Copy</kbd>' has been provided. This is equivelent to
324using the '<kbd>Src</kbd>' with the special <A HREF="../www/command-line-options.html#define"
325>-define</A> option '<kbd>compose:outside-overlay</kbd>' set to
326'<kbd>false</kbd>', so as to only modify the overlaid area, without clearing
327the rest of the image outside the overlaid area. </p>
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]328
329<br><br>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]330
331<p>The following mathemathical composition methods are also available. </p>
332
333<table class="doc">
334 <tbody>
335 <tr valign="top">
336 <th align="left" style="width: 8%">Method</th>
337 <th align="left">Description</th>
338 </tr>
339
340 <tr valign="top">
341 <td valign="top">multiply</td>
342 <td valign="top">The source is multiplied by the destination and replaces
343 the destination. The resultant color is always at least as dark as
344 either of the two constituent colors. Multiplying any color with black
345 produces black. Multiplying any color with white leaves the original
346 color unchanged.</td>
347 </tr>
348
349 <tr valign="top">
350 <td valign="top">screen</td>
351 <td valign="top">The source and destination are complemented and then
352 multiplied and then replace the destination. The resultant color is
353 always at least as light as either of the two constituent colors.
354 Screening any color with white produces white. Screening any color
355 with black leaves the original color unchanged.</td>
356 </tr>
357
358 <tr valign="top">
359 <td valign="top">plus</td>
360 <td valign="top">The source is added to the destination and replaces the
361 destination. This operator is useful for averaging or a controled
362 merger of two images, rather than a direct overlay.</td>
363 </tr>
364
365 <tr valign="top">
366 <td valign="top">add</td>
367 <td valign="top">As per 'plus' but transparency data is treated as matte
368 values. As such any transparent areas in either image remain
369 transparent. </td>
370 </tr>
371
372 <tr valign="top">
373 <td valign="top">minus</td>
374 <td valign="top">Subtract the colors in the source image from the
375 destination image. When transparency is involved, opaque areas is
376 subtracted from any destination opaque areas. </td>
377 </tr>
378
379 <tr valign="top">
380 <td valign="top">subtract</td>
381 <td valign="top">Subtract the colors in the source image from the
382 destination image. When transparency is involved transparent areas are
383 subtracted, so only the opaque areas in the source remain opaque in
384 the destination image. </td>
385 </tr>
386
387 <tr valign="top">
388 <td valign="top">difference</td>
389 <td valign="top">Subtracts the darker of the two constituent colors from
390 the lighter. Painting with white inverts the destination color.
391 Painting with black produces no change.</td>
392 </tr>
393
394 <tr valign="top">
395 <td valign="top">exclusion</td>
396 <td valign="top">Produces an effect similar to that of 'difference', but
397 appears as lower contrast. Painting with white inverts the
398 destination color. Painting with black produces no change.</td>
399 </tr>
400
401 <tr valign="top">
402 <td valign="top">darken</td>
403 <td valign="top">Selects the darker of the destination and source colors.
404 The destination is replaced with the source when the source is darker,
405 otherwise it is left unchanged.</td>
406 </tr>
407
408 <tr valign="top">
409 <td valign="top">lighten</td>
410 <td valign="top">Selects the lighter of the destination and source colors.
411 The destination is replaced with the source when the source is
412 lighter, otherwise it is left unchanged. </td>
413 </tr>
414
415 </tbody>
416</table>
417
418<p>Typically these use the default 'Over' alpha blending when transparencies
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]419are also involved, except for 'Plus' which uses a 'plus' alpha blending. This
420means the alpha channel of both images will only be used to ensure that any
421visible input remains visible even in parts not overlaid. It also means that
422any values are weighted by the alpha channel of the input and output images.
423This 'Over' alpha blending is also applied to the lighting composition methods
424below. </p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]425
426<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]427(enabled by default) with the <a href="../www/command-line-options.html#channel"
428>-channel</a> setting, then the above mathematical compositions will nolonger
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]429syncronise its actions with the alpha channel. Instead the math composition
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]430will be applied on an individual channel basis as defined by the <a
431href="../www/command-line-options.html#channel"
432>-channel</a>. This includes the alpha channel. This special usage
433allows you to perform true mathematics of the image channels, without alpha
434compostion effects, becomming involved. </p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]435
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]436<p>This special flag is not applied to the lighting composition methods (see
437below) even though they are closely related to mathematical composition
438methods.</p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]439
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]440<br><br>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]441
442<p>The following lighting composition methods are also available. </p>
443
444<table class="doc">
445 <tbody>
446 <tr valign="top">
447 <th align="left" style="width: 8%">Method</th>
448 <th align="left">Description</th>
449 </tr>
450
451 <tr valign="top">
452 <td valign="top">linear-dodge</td>
453 <td valign="top">This is equivelent to 'Plus' in that the color channels
454 are simply added, however it does not 'Plus' the alpha channel, but
455 uses the normal 'Over' alpha blending, which transparencies are
456 involved. Produces a sort of additive multiply-like result. Added
457 ImageMagick version 6.5.4-3. </td>
458 </tr>
459
460 <tr valign="top">
461 <td valign="top">linear-burn</td>
462 <td valign="top">As 'Linear-Dodge', but also subtract one from the result.
463 Sort of a additive 'Screen' of the images. Added ImageMagick version
464 6.5.4-3. </td>
465 </tr>
466
467 <tr valign="top">
468 <td valign="top">color-dodge</td>
469 <td valign="top">Brightens the destination color to reflect the source
470 color. Painting with black produces no change.</td>
471 </tr>
472
473 <tr valign="top">
474 <td valign="top">color-burn</td>
475 <td valign="top">Darkens the destination color to reflect the source
476 color. Painting with white produces no change. Fixed in ImageMagick
477 version 6.5.4-3. </td>
478 </tr>
479
480 <tr valign="top">
481 <td valign="top">overlay</td>
482 <td valign="top">Multiplies or screens the colors, dependent on the
483 destination color. Source colors overlay the destination whilst
484 preserving its highlights and shadows. The destination color is not
485 replaced, but is mixed with the source color to reflect the lightness
486 or darkness of the destination.</td>
487 </tr>
488
489 <tr valign="top">
490 <td valign="top">hard-light</td>
491 <td valign="top">Multiplies or screens the colors, dependent on the source
492 color value. If the source color is lighter than 0.5, the destination
493 is lightened as if it were screened. If the source color is darker
494 than 0.5, the destination is darkened, as if it were multiplied. The
495 degree of lightening or darkening is proportional to the difference
496 between the source color and 0.5. If it is equal to 0.5 the
497 destination is unchanged. Painting with pure black or white produces
498 black or white.</td>
499 </tr>
500
501
502 <tr valign="top">
503 <td valign="top">linear-light</td>
504 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn
505 instead. Increases contrast slightly with an impact on the
506 foreground's tonal values.</td>
507 </tr>
508
509 <tr valign="top">
510 <td valign="top">soft-light</td>
511 <td valign="top">Darkens or lightens the colors, dependent on the source
512 color value. If the source color is lighter than 0.5, the destination
513 is lightened. If the source color is darker than 0.5, the destination
514 is darkened, as if it were burned in. The degree of darkening or
515 lightening is proportional to the difference between the source color
516 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting
517 with pure black or white produces a distinctly darker or lighter area,
518 but does not result in pure black or white. Fixed in ImageMagick
519 version 6.5.4-3. </td>
520 </tr>
521
522 <tr valign="top">
523 <td valign="top">pegtop-light</td>
524 <td valign="top">Almost equivelent to 'Soft-Light', but using a
525 continuious mathematical formula rather than two conditionally
526 selected formulae. Added ImageMagick version 6.5.4-3. </td>
527 </tr>
528
529 <tr valign="top">
530 <td valign="top">vivid-light</td>
531 <td valign="top">A modified 'Linear-Light' designed to preserve very stong
532 primary and secondary colors in the image. Added ImageMagick version
533 6.5.4-3. </td>
534 </tr>
535
536 <tr valign="top">
537 <td valign="top">pin-light</td>
538 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings,
539 to similate the effects of a strong 'pinhole' light source. Added
540 ImageMagick version 6.5.4-3. </td>
541 </tr>
542
543 </tbody>
544</table>
545
546
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]547<br><br>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]548
549<p>Also included are these special purpose compose methods:</p>
550
551<table class="doc">
552 <tbody>
553 <tr valign="top">
554 <th align="left" style="width: 8%">Method</th>
555 <th align="left">Description</th>
556 </tr>
557
558 <tr valign="top">
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]559 <td valign="top">copy</td>
560 <td valign="top">This is equivelent to the Duff-Porter composition method
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]561 '<kbd>Src,</kbd>' but without clearing the parts of the destination
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]562 image that is not overlaid. </td>
563 </tr>
564
565 <tr valign="top">
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]566 <td valign="top">copy-*</td>
567 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan,
568 Magenta, Yellow, Black, or Opacity) in the source image to the
569 same channel in the destination image. If the channel specified
570 does not exist in the source image, (which can only happen for methods,
571 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is
572 assumed that the source image is a special grayscale channel image
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]573 of the values that is to be copied. </td>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]574 </tr>
575
576 <tr valign="top">
577 <td valign="top">change-mask</td>
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]578 <td valign="top">Replace any destination pixel that is the similar to the
579 source images pixel (as defined by the current <a
580 href="../www/command-line-options.html#fuzz">-fuzz</a> factor), with transparency.
581 </td>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]582 </tr>
583 </tbody>
584</table>
585
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]586<br><br>
587
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]588<p>On top of these composed methods are a few special ones that not only require
589the two images that are being merged or overlaid, but have some extra numerical
590arguments, which are tabled below. </p>
591
592<p>In the "<code>composite</code>" command these composition methods are
593selected using special options with the arguments needed. They are usually,
594but not always, the same name as the composte 'method' they use, and replaces
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]595the normal use of the <a href="../www/command-line-options.html#compose" >-compose</a>
596setting in the "<code>composite</code>" command. For example... </p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]597
598<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>composite ... -blend 50x50 ...</span></p>
599<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]600these extra arguments to its <a href="../www/command-line-options.html#composite"
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]601>-composite</a> operator, using the special <a href="../www/command-line-options.html#define">-define</a>
602attribute of '<kbd class="arg">compose:args</kbd>'. This means you can now
603make use of these special argumented <a href="../www/command-line-options.html#compose"
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]604>-compose</a> methods, those the argument and the method both need to be set
605separatally. For example... </p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]606
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]607<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]608<p>The following is a table of these special 'argumented' compose methods,
609with a brief summary of what they do. For more details see the equivalent
610"composite" command option name. </p>
611
612<table class="doc">
613 <tbody>
614 <tr valign="top">
615 <th align="left" style="width: 8%">Method</th>
616 <th align="left">Description</th>
617 </tr>
618
619 <tr valign="top">
620 <td valign="top">dissolve</td>
621 <td valign="top">Arguments:
622 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]623 <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]624 <br>Dissolve the 'source' image by the percentage given before overlaying
625 'over' the 'destination' image. If <em class="arg">src_percent</em> is
626 greater than 100, it starts dissolving the main image so it will
627 become transparent at a value of '<kbd class="arg">200</kbd>'. If
628 both percentages are given, each image are dissolved to the
629 percentages given.
630 </td>
631 </tr>
632
633 <tr valign="top">
634 <td valign="top">blend</td>
635 <td valign="top">Arguments:
636 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]637 <br>Equivalent to "<code>composite</code>" <a
638 href="../www/command-line-options.html#blend">-blend</a>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]639 <br>Average the images together ('plus') according to the percentages
640 given and each pixels transparency. If only a single percentage value
641 is given it sets the weight of the composite or 'source' image, while
642 the background image is weighted by the exact opposite amount. That is
643 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of
644 the 'destination' image. Thus it is equivalent to <kbd>-blend
645 30x70</kbd>.
646 </td>
647 </tr>
648
649 <tr valign="top">
650 <td valign="top">mathematics</td>
651 <td valign="top">Arguments: <em class="arg">A, B, C, D</em>
652 <br>Not available in "<code>composite</code>" at this time.
653 <br>Merge the source and destination images according to the formula
654 <br>&nbsp; &nbsp; &nbsp;<code>A*Sc*Dc + B*Sc + C*Dc + D</code>
655 <br>Can be used to generate a custom composition method that would
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]656 otherwise need to be implemented using the slow <a
657 href="../www/command-line-options.html#fx">-fx</a> DIY image operator. Added
658 to ImageMagick version 6.5.4-3.
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]659 <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]660 if the 'Sync' flag is removed from <a
661 href="../www/command-line-options.html#channel" >-channel</a>, just like all
662 the other mathematical compostion methods above.
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]663 </td>
664 </tr>
665
666 <tr valign="top">
667 <td valign="top">modulate</td>
668 <td valign="top">Arguments:
669 <em class="arg">brightness</em>[x<em class="arg">saturation</em>]
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]670 <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]671 <br>Take a grayscale image (with alpha mask) and modify the destination
672 image's brightness according to watermark image's grayscale value and
673 the <em class="arg">brightness</em> percentage. The destinations
674 color saturation attribute is just direct modified by the <em
675 class="arg">saturation</em> percentage, which defaults to 100 percent
676 (no color change).
677
678 </td>
679 </tr>
680
681 <tr valign="top">
682 <td valign="top">displace</td>
683 <td valign="top">Arguments:
684 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%]
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]685 <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]686 <br>With this option, the 'overlay' image, and optionally the 'mask'
687 image, is used as a relative displacement map, which is used to
688 displace the lookup of what part of the destination image is seen at
689 each point of the overlaid area. Much like the displacement map is a
690 'lens' that distorts the original 'background' image behind it.
691 <br><br>
692 The X-scale is modilated by the 'red' channel of the overlay image
693 while the Y-scale is modulated by the green channel, (the mask image
694 if given is rolled into green channel of the overlay image. This
695 separation allows you to modulate the X and Y lookup displacement
696 separatally allowing you to di 2 dimentional displacements, rather
697 than 1 dimentional verctored displacements (using grayscale image).
698 <br><br>
699 If the overlay image contains transparency this is used as a mask
700 of the resulting image to remove 'invalid' pixels.
701 <br><br>
702 The '%' flag makes the displacement scale relative to the size of the
703 overlay image (100% = half width/height of image). Using '!' switches
704 percentage arguments to refer to the destination image size instead.
705 <br><br>
706 Special flags were added Added to ImageMagick version 6.5.3-5.
707 </td>
708 </tr>
709
710 <tr valign="top">
711 <td valign="top">distort</td>
712 <td valign="top">Arguments:
713 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em
714 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%]
715 <br>Not available in "<code>composite</code>" at this time.
716 <br>Exactly as per 'Displace' (above), but using absolute coordinates,
717 relative to the center of the overlay (or that given). Basically
718 allows you to generate absolute distortion maps where 'black' will
719 look up the left/top edge, and 'white' looks up the bottom/right
720 edge of the destination image, according to the scale given.
721 <br><br>
722 The '!' flag not only switches percentage scaling, to use the
723 destination image, but also the image the center offset of the lookup.
724 This means the overlay can lookup a completely different region of the
725 destination image.
726 <br><br>
727 Added to ImageMagick version 6.5.3-5.
728 </td>
729 </tr>
730
731 <tr valign="top">
732 <td valign="top">blur</td>
733 <td valign="top">Arguments:
734 <em class="arg">Width</em>[x<em class="arg">Height</em
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]735 >[+<em class="arg">Angle</em>][+<em class="arg">Angle2</em>]]
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]736 <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]737 <br>A Variable Blur Mapping Composition method, where each pixel in the
738 overlaid region is replaced with an Elliptical Weighted Average (EWA),
739 with an ellipse (typically a circle) of the given sigma size, scaled
740 according to overlay (source image) grayscale mapping.
741 <br><br>
742 As per 'Displace' and 'Distort', the red channel will modulate the
743 width of the ellipse, while the green channel will modulate the height
cristy075ad252010-10-30 21:56:17 +0000[diff] [blame]744 of the ellipse. If a single Angle value is given in the arguments,
745 then the ellipse will then be rotated by the angle specifed.
746 <br><br>
747 Normally the blue channel of the mapping overlay image is ignored.
748 However if a second ellipse angle is given, then it is assumed that
749 the blue channel defines a variable angle for the ellipse ranging from
750 the first angle to the second angle given. This allows to generate
751 radial blurs, or a rough approximation for rotational blur. Or any mix
752 of the two.
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]753 <br><br>
754 Added to ImageMagick version 6.5.4-0.
755 </td>
756 </tr>
757
758 </tbody>
759</table>
760
761<p>To print a complete list of all the available compose operators, use <a
cristyabd337d2010-08-17 01:06:59 +0000[diff] [blame]762href="../www/command-line-options.html#list">-list compose</a>.</p>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]763
764
765
766</div>
767
768<div id="linkbar">
769 <span id="linkbar-west">&nbsp;</span>
770 <span id="linkbar-center">
771 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> &bull;
772 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a>
773 </span>
774 <span id="linkbar-east">&nbsp;</span>
775 </div>
776 <div class="footer">
cristy7e41fe82010-12-04 23:12:08 +0000[diff] [blame]777 <span id="footer-west">&copy; 1999-2011 ImageMagick Studio LLC</span>
cristybc9539a2010-08-16 18:06:20 +0000[diff] [blame]778 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span>
779 </div>
780 <div style="clear: both; margin: 0; width: 100%; "></div>
781 <script type="text/javascript">
782 var _gaq = _gaq || [];
783 _gaq.push(['_setAccount', 'UA-17690367-1']);
784 _gaq.push(['_trackPageview']);
785
786 (function() {
787 var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
788 ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
789 var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
790 })();
791 </script>
792</body>
793</html>