Gitiles
Code Review Sign In
gerrit-public.fairphone.software / platform / external / ImageMagick / 2744bd91de384c5ef276f9afb4dec138f76bfd0b / . / www / api / histogram.html
blob: 187f593f680e556e8bb2137d88d95a1ad1359ead [file] [log] [blame]
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
3<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
4<head>
5 <meta name="verify-v1" content="g222frIIxcQTrvDR3NBRUSKP3AnMNoqxOkIniCEkV7U=" />
6 <link rel="meta" type="application/rdf+xml" title="ICI" href="http://imagemagick.org/ici.rdf" />
7 <style type="text/css" media="screen,projection"><!--
8 @import url("../../www/magick.css");
9 --></style>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]10 <link rel="shortcut icon" href="../../images/wand.ico" type="images/vnd.microsoft.icon"/>
11 <title>ImageMagick: MagickCore, C API for ImageMagick: Image Histograms</title>
12 <meta http-equiv="Content-Language" content="en-US"/>
13 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
14 <meta http-equiv="Reply-to" content="magick-users@imagemagick.org"/>
15 <meta name="Generator" content="PHP"/>
16 <meta name="Keywords" content="magickcore, c, api, for, imagemagick:, image, histograms, ImageMagick, ImageMagic, MagickCore, MagickWand, PerlMagick, Magick++, RMagick, PythonMagick, JMagick, TclMagick, Image, Magick, Magic, Wand, ImageMagickObject, Swiss, Army, Knife, Image, Processing"/>
17 <meta name="Description" content="ImageMagick® is a software suite to create, edit, and compose bitmap images. It can read, convert and write images in a variety of formats (about 100) including GIF, JPEG, JPEG-2000, PNG, PDF, PhotoCD, TIFF, and DPX. Use ImageMagick to translate, flip, mirror, rotate, scale, shear and transform images, adjust image colors, apply various special effects, or draw text, lines, polygons, ellipses and Bézier curves. ImageMagick is free software delivered as a ready-to-run binary distribution or as source code that you can freely use, copy, modify, and distribute. Its license is compatible with the GPL. It runs on all major operating systems. The functionality of ImageMagick is typically utilized from the command line or you can use the features from programs written in your favorite programming language. Choose from these interfaces: MagickCore (C), MagickWand (C), ChMagick (Ch), Magick++ (C++), JMagick (Java), L-Magick (Lisp), PascalMagick (Pascal), PerlMagick (Perl), MagickWand for PHP (PHP), PythonMagick (Python), RMagick (Ruby), or TclMagick (Tcl/TK). With a language interface, use ImageMagick to modify or create images automagically and dynamically."/>
18 <meta name="Rating" content="GENERAL"/>
19 <meta name="Robots" content="INDEX, FOLLOW"/>
20 <meta name="Generator" content="ImageMagick Studio LLC"/>
21 <meta name="Author" content="ImageMagick Studio LLC"/>
22 <meta name="Revisit-after" content="2 DAYS"/>
23 <meta name="Resource-type" content="document"/>
24 <meta name="Copyright" content="Copyright (c) 1999-2009 ImageMagick Studio LLC"/>
25 <meta name="Distribution" content="Global"/>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]26</head>
27
28<body id="www-imagemagick-org">
29<div class="titlebar">
30<a href="../../index.html">
31 <img src="../../images/script.png" alt="[ImageMagick]"
32 style="width: 350px; height: 60px; margin: 28px auto; float: left;" /></a>
33<a href="http://www.networkredux.com">
34 <img src="../../images/networkredux.png" alt="[sponsor]"
35 style="margin: 45px auto; border: 0px; float: left;" /></a>
36<a href="http://www.imagemagick.org/discourse-server/">
37 <img src="../../images/logo.jpg" alt=""
38 style="width: 114px; height: 118px; border: 0px; float: right;" /></a>
39<a href="../../index.html">
40 <img src="../../images/sprite.jpg" alt=""
41 style="width: 114px; height: 118px; border: 0px; float: right;" /></a>
42</div>
43
44<div class="eastbar">
45
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]46<div class="menu">
47 <a href="../../index.html">About ImageMagick</a>
48</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]49<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]50<div class="menu">
51 <a href="../../www/command-line-tools.html">Command-line Tools</a>
52</div>
53<div class="sub">
54 <a href="../../www/command-line-processing.html">Processing</a>
55</div>
56<div class="sub">
57 <a href="../../www/command-line-options.html">Options</a>
58</div>
59<div class="sub">
60 <a href="http://www.imagemagick.org/Usage/">Usage</a>
61</div>
62<div class="menu">
63 <a href="../../www/api.html">Program Interfaces</a>
64</div>
65<div class="sub">
66 <a href="../../www/magick-wand.html">MagickWand</a>
67</div>
68<div class="sub">
69 <a href="../../www/magick-core.html">MagickCore</a>
70</div>
71<div class="sub">
72 <a href="../../www/perl-magick.html">PerlMagick</a>
73</div>
74<div class="sub">
75 <a href="../../Magick++/">Magick++</a>
76</div>
77<div class="menu">
78 <a href="../../www/architecture.html">Architecture</a>
79</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]80<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]81<div class="menu">
82 <a href="../../www/install-source.html">Install from Source</a>
83</div>
84<div class="sub">
85 <a href="../../www/install-source.html#unix">Unix</a>
86</div>
87<div class="sub">
88 <a href="../../www/install-source.html#windows">Windows</a>
89 </div>
90<div class="menu">
91 <a href="../../www/binary-releases.html">Binary Releases</a>
92</div>
93<div class="sub">
94 <a href="../../www/binary-releases.html#unix">Unix</a>
95</div>
96<div class="sub">
97 <a href="../../www/binary-releases.html#macosx">Mac OS X</a>
98</div>
99<div class="sub">
100 <a href="../../www/binary-releases.html#windows">Windows</a>
101</div>
102<div class="menu">
103 <a href="../../www/resources.html">Resources</a>
104</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]105<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]106<div class="menu">
107 <a href="../../www/download.html">Download</a>
108</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]109<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]110<div class="menu">
111 <a href="../http://www.imagemagick.org/script/search.php">Search</a>
112</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]113<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]114<div class="menu">
115 <a href="../../www/sitemap.html">Site Map</a>
116</div>
117<div class="sub">
118 <a href="../../www/links.html">Links</a>
119</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]120<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]121<div class="menu">
122 <a href="../../www/sponsors.html">Sponsors:</a>
123
124<div class="sponsbox">
125<div class="sponsor">
cristy2744bd92009-11-08 22:57:52 +0000[diff] [blame^]126 <a href="http://www.blumenversender.com">Blumenversand</a><!-- 201005010120 -->
cristy916e1922009-10-01 12:52:47 +0000[diff] [blame]127</div>
128<div class="sponsor">
129 <a href="http://www.online-kredit-index.de">Kredit</a><!-- 201003010120 Buchhorn -->
cristyc1c61662009-09-30 14:04:37 +0000[diff] [blame]130</div>
131<div class="sponsor">
cristyb4c03bb2009-09-27 13:55:46 +0000[diff] [blame]132 <a href="http://www.print24.de/">Druckerei</a><!-- 201009010720 -->
133</div>
134<div class="sponsor">
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]135 <a href="http://www.goyax.de">Börse</a><!-- 201001000240 Gewiese digital-finance.de -->
136</div>
137<div class="sponsor">
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]138 <a href="http://www.allesdruck.de">Druckerei Online</a><!-- 201012001200 allesdruck.de-->
139</div>
140<div class="sponsor">
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]141 <a href="http://www.who-sells-it.com/">Free Catalogs</a><!-- 201002010000 -->
142</div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]143</div>
144</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]145
146
147</div>
148
149<div class="main">
150
cristy83543962009-10-16 19:04:28 +0000[diff] [blame]151<p class="navigation-index">[<a href="#GetImageHistogram">GetImageHistogram</a> &bull; <a href="#IsHistogramImage">IsHistogramImage</a> &bull; <a href="#IsPaletteImage">IsPaletteImage</a> &bull; <a href="#MinMaxStretchImage">MinMaxStretchImage</a> &bull; <a href="#GetNumberColors">GetNumberColors</a> &bull; <a href="#UniqueImageColors">UniqueImageColors</a>]</p>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]152
153<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
cristy83543962009-10-16 19:04:28 +0000[diff] [blame]154_8c.html" target="source" name="GetImageHistogram">GetImageHistogram</a></h2>
155<div class="doc-section">
156
157<p>GetImageHistogram() returns the unique colors in an image.</p></ol>
158
159<p>The format of the GetImageHistogram method is:</p>
160
161<pre class="code">
162 unsigned long GetImageHistogram(const Image *image,
163 unsigned long *number_colors,ExceptionInfo *exception)
164</pre>
165
166<p>A description of each parameter follows.</p></ol>
167
168<h5>image</h5>
169<ol><p>the image.</p></ol>
170
171<h5>file</h5>
172<ol><p>Write a histogram of the color distribution to this file handle.</p></ol>
173
174<h5>exception</h5>
175<ol><p>return any errors or warnings in this structure.</p></ol>
176
177 </div>
178<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
179_8c.html" target="source" name="IsHistogramImage">IsHistogramImage</a></h2>
180<div class="doc-section">
181
182<p>IsHistogramImage() returns MagickTrue if the image has 1024 unique colors or less.</p></ol>
183
184<p>The format of the IsHistogramImage method is:</p>
185
186<pre class="code">
187 MagickBooleanType IsHistogramImage(const Image *image,
188 ExceptionInfo *exception)
189</pre>
190
191<p>A description of each parameter follows.</p></ol>
192
193<h5>image</h5>
194<ol><p>the image.</p></ol>
195
196<h5>exception</h5>
197<ol><p>return any errors or warnings in this structure.</p></ol>
198
199 </div>
200<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
201_8c.html" target="source" name="IsPaletteImage">IsPaletteImage</a></h2>
202<div class="doc-section">
203
204<p>IsPaletteImage() returns MagickTrue if the image is PseudoClass and has 256 unique colors or less.</p></ol>
205
206<p>The format of the IsPaletteImage method is:</p>
207
208<pre class="code">
209 MagickBooleanType IsPaletteImage(const Image *image,
210 ExceptionInfo *exception)
211</pre>
212
213<p>A description of each parameter follows.</p></ol>
214
215<h5>image</h5>
216<ol><p>the image.</p></ol>
217
218<h5>exception</h5>
219<ol><p>return any errors or warnings in this structure.</p></ol>
220
221 </div>
222<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]223_8c.html" target="source" name="MinMaxStretchImage">MinMaxStretchImage</a></h2>
224<div class="doc-section">
225
226<p>MinMaxStretchImage() uses the exact minimum and maximum values found in each of the channels given, as the BlackPoint and WhitePoint to linearly stretch the colors (and histogram) of the image. The stretch points are also moved further inward by the adjustment values given.</p></ol>
227
228<p>If the adjustment values are both zero this function is equivelent to a perfect normalization (or autolevel) of the image.</p></ol>
229
230<p>Each channel is stretched independantally of each other (producing color distortion) unless the special 'SyncChannels' flag is also provided in the channels setting. If this flag is present the minimum and maximum point will be extracted from all the given channels, and those channels will be stretched by exactly the same amount (preventing color distortion).</p></ol>
231
232<p>The 'SyncChannels' is turned on in the 'DefaultChannels' setting by default.</p></ol>
233
234<p>The format of the MinMaxStretchImage method is:</p>
235
236<pre class="code">
237 MagickBooleanType MinMaxStretchImage(Image *image,
238 const ChannelType channel, const double black_adjust,
239 const double white_adjust)
240</pre>
241
242<p>A description of each parameter follows:</p></ol>
243
244<h5>image</h5>
245<ol><p>The image to auto-level</p></ol>
246
247<h5>channel</h5>
248<ol><p>The channels to auto-level. If the special 'SyncChannels' flag is set, all the given channels are stretched by the same amount.</p></ol>
249
250<h5>black_adjust, white_adjust</h5>
251<ol><p>Move the Black/White Point inward from the minimum and maximum points by this color value.</p></ol>
252
253 </div>
cristy83543962009-10-16 19:04:28 +0000[diff] [blame]254<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
255_8c.html" target="source" name="GetNumberColors">GetNumberColors</a></h2>
256<div class="doc-section">
257
258<p>GetNumberColors() returns the number of unique colors in an image.</p></ol>
259
260<p>The format of the GetNumberColors method is:</p>
261
262<pre class="code">
263 unsigned long GetNumberColors(const Image *image,FILE *file,
264 ExceptionInfo *exception)
265</pre>
266
267<p>A description of each parameter follows.</p></ol>
268
269<h5>image</h5>
270<ol><p>the image.</p></ol>
271
272<h5>file</h5>
273<ol><p>Write a histogram of the color distribution to this file handle.</p></ol>
274
275<h5>exception</h5>
276<ol><p>return any errors or warnings in this structure.</p></ol>
277
278 </div>
279<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
280_8c.html" target="source" name="UniqueImageColors">UniqueImageColors</a></h2>
281<div class="doc-section">
282
283<p>UniqueImageColors() returns the unique colors of an image.</p></ol>
284
285<p>The format of the UniqueImageColors method is:</p>
286
287<pre class="code">
288 Image *UniqueImageColors(const Image *image,ExceptionInfo *exception)
289</pre>
290
291<p>A description of each parameter follows.</p></ol>
292
293<h5>image</h5>
294<ol><p>the image.</p></ol>
295
296<h5>exception</h5>
297<ol><p>return any errors or warnings in this structure.</p></ol>
298
299 </div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]300
301</div>
302
303<div id="linkbar">
304 <!-- <span id="linkbar-west">&nbsp;</span> -->
305 <span id="linkbar-center">
306 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> &bull;
307 <a href="../../www/mailing-list.html">Mailing Lists</a> &bull;
cristy2744bd92009-11-08 22:57:52 +0000[diff] [blame^]308 <a href="http://studio.webbyland.com/ImageMagick/MagickStudio/scripts/MagickStudio.cgi">Studio</a>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]309 </span>
310 <span id="linkbar-east">&nbsp;</span>
311 </div>
312 <div class="footer">
313 <span id="footer-west">&copy; 1999-2009 ImageMagick Studio LLC</span>
314 <span id="footer-east"> <a href="../http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span>
315 </div>
316 <div style="clear: both; margin: 0; width: 100%; "></div>
317</body>
318</html>