Gitiles
Code Review Sign In
gerrit-public.fairphone.software / platform / external / ImageMagick / 08a8820ef55dcd8ce5255aec02e86f556e7e323c / . / www / api / histogram.html
blob: 300a515793d1eca5055d6183db9ae152d71f7aee [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>
cristy1f9e1ed2009-11-18 04:09:38 +0000[diff] [blame]5 <meta http-equiv="Content-Type" value="application/xhtml+xml" />
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]6 <meta name="verify-v1" content="g222frIIxcQTrvDR3NBRUSKP3AnMNoqxOkIniCEkV7U=" />
7 <link rel="meta" type="application/rdf+xml" title="ICI" href="http://imagemagick.org/ici.rdf" />
8 <style type="text/css" media="screen,projection"><!--
9 @import url("../../www/magick.css");
10 --></style>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]11 <link rel="shortcut icon" href="../../images/wand.ico" type="images/vnd.microsoft.icon"/>
12 <title>ImageMagick: MagickCore, C API for ImageMagick: Image Histograms</title>
13 <meta http-equiv="Content-Language" content="en-US"/>
14 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
15 <meta http-equiv="Reply-to" content="magick-users@imagemagick.org"/>
16 <meta name="Generator" content="PHP"/>
17 <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"/>
18 <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."/>
19 <meta name="Rating" content="GENERAL"/>
20 <meta name="Robots" content="INDEX, FOLLOW"/>
21 <meta name="Generator" content="ImageMagick Studio LLC"/>
22 <meta name="Author" content="ImageMagick Studio LLC"/>
23 <meta name="Revisit-after" content="2 DAYS"/>
24 <meta name="Resource-type" content="document"/>
cristy16af1cb2009-12-11 21:38:29 +0000[diff] [blame]25 <meta name="Copyright" content="Copyright (c) 1999-2010 ImageMagick Studio LLC"/>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]26 <meta name="Distribution" content="Global"/>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]27</head>
28
29<body id="www-imagemagick-org">
30<div class="titlebar">
31<a href="../../index.html">
32 <img src="../../images/script.png" alt="[ImageMagick]"
33 style="width: 350px; height: 60px; margin: 28px auto; float: left;" /></a>
34<a href="http://www.networkredux.com">
35 <img src="../../images/networkredux.png" alt="[sponsor]"
36 style="margin: 45px auto; border: 0px; float: left;" /></a>
37<a href="http://www.imagemagick.org/discourse-server/">
38 <img src="../../images/logo.jpg" alt=""
39 style="width: 114px; height: 118px; border: 0px; float: right;" /></a>
40<a href="../../index.html">
41 <img src="../../images/sprite.jpg" alt=""
42 style="width: 114px; height: 118px; border: 0px; float: right;" /></a>
43</div>
44
45<div class="eastbar">
46
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]47<div class="menu">
48 <a href="../../index.html">About ImageMagick</a>
49</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]50<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]51<div class="menu">
52 <a href="../../www/command-line-tools.html">Command-line Tools</a>
53</div>
54<div class="sub">
55 <a href="../../www/command-line-processing.html">Processing</a>
56</div>
57<div class="sub">
58 <a href="../../www/command-line-options.html">Options</a>
59</div>
60<div class="sub">
61 <a href="http://www.imagemagick.org/Usage/">Usage</a>
62</div>
63<div class="menu">
64 <a href="../../www/api.html">Program Interfaces</a>
65</div>
66<div class="sub">
67 <a href="../../www/magick-wand.html">MagickWand</a>
68</div>
69<div class="sub">
70 <a href="../../www/magick-core.html">MagickCore</a>
71</div>
72<div class="sub">
73 <a href="../../www/perl-magick.html">PerlMagick</a>
74</div>
75<div class="sub">
76 <a href="../../Magick++/">Magick++</a>
77</div>
78<div class="menu">
79 <a href="../../www/architecture.html">Architecture</a>
80</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]81<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]82<div class="menu">
83 <a href="../../www/install-source.html">Install from Source</a>
84</div>
85<div class="sub">
86 <a href="../../www/install-source.html#unix">Unix</a>
87</div>
88<div class="sub">
89 <a href="../../www/install-source.html#windows">Windows</a>
90 </div>
91<div class="menu">
92 <a href="../../www/binary-releases.html">Binary Releases</a>
93</div>
94<div class="sub">
95 <a href="../../www/binary-releases.html#unix">Unix</a>
96</div>
97<div class="sub">
98 <a href="../../www/binary-releases.html#macosx">Mac OS X</a>
99</div>
100<div class="sub">
101 <a href="../../www/binary-releases.html#windows">Windows</a>
102</div>
103<div class="menu">
104 <a href="../../www/resources.html">Resources</a>
105</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]106<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]107<div class="menu">
108 <a href="../../www/download.html">Download</a>
109</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]110<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]111<div class="menu">
112 <a href="../http://www.imagemagick.org/script/search.php">Search</a>
113</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]114<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]115<div class="menu">
116 <a href="../../www/sitemap.html">Site Map</a>
117</div>
118<div class="sub">
119 <a href="../../www/links.html">Links</a>
120</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]121<div class="sep"></div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]122<div class="menu">
123 <a href="../../www/sponsors.html">Sponsors:</a>
124
125<div class="sponsbox">
126<div class="sponsor">
cristy1f9e1ed2009-11-18 04:09:38 +0000[diff] [blame]127 <a href="http://www.tomsgutscheine.de">Tom's Gutscheine</a><!-- 201005010360 invendio.de-->
128</div>
129<div class="sponsor">
cristycdbe2742010-02-07 19:30:44 +0000[diff] [blame]130 <a href="http://www.online-kredit-index.de">Kredit</a><!-- 201007010120 Buchhorn -->
cristy916e1922009-10-01 12:52:47 +0000[diff] [blame]131</div>
132<div class="sponsor">
cristy0f61e612009-11-10 20:03:57 +0000[diff] [blame]133 <a href="http://www.blumenversender.com">Blumenversand</a><!-- 201005010120 -->
cristyc1c61662009-09-30 14:04:37 +0000[diff] [blame]134</div>
135<div class="sponsor">
cristyb4c03bb2009-09-27 13:55:46 +0000[diff] [blame]136 <a href="http://www.print24.de/">Druckerei</a><!-- 201009010720 -->
137</div>
138<div class="sponsor">
cristy16ff93c2010-01-13 23:18:07 +0000[diff] [blame]139 <a href="http://www.goyax.de">Börse</a><!-- 201004010240 Gewiese digital-finance.de -->
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]140</div>
141<div class="sponsor">
cristy16ff93c2010-01-13 23:18:07 +0000[diff] [blame]142 <a href="http://www.allesdruck.de">Druckerei Online</a><!-- 201012011200 allesdruck.de-->
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]143</div>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]144</div>
145</div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]146
147
148</div>
149
150<div class="main">
151
cristy83543962009-10-16 19:04:28 +0000[diff] [blame]152<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]153
154<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
cristy83543962009-10-16 19:04:28 +0000[diff] [blame]155_8c.html" target="source" name="GetImageHistogram">GetImageHistogram</a></h2>
156<div class="doc-section">
157
158<p>GetImageHistogram() returns the unique colors in an image.</p></ol>
159
160<p>The format of the GetImageHistogram method is:</p>
161
162<pre class="code">
163 unsigned long GetImageHistogram(const Image *image,
164 unsigned long *number_colors,ExceptionInfo *exception)
165</pre>
166
167<p>A description of each parameter follows.</p></ol>
168
169<h5>image</h5>
170<ol><p>the image.</p></ol>
171
172<h5>file</h5>
173<ol><p>Write a histogram of the color distribution to this file handle.</p></ol>
174
175<h5>exception</h5>
176<ol><p>return any errors or warnings in this structure.</p></ol>
177
178 </div>
179<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
180_8c.html" target="source" name="IsHistogramImage">IsHistogramImage</a></h2>
181<div class="doc-section">
182
183<p>IsHistogramImage() returns MagickTrue if the image has 1024 unique colors or less.</p></ol>
184
185<p>The format of the IsHistogramImage method is:</p>
186
187<pre class="code">
188 MagickBooleanType IsHistogramImage(const Image *image,
189 ExceptionInfo *exception)
190</pre>
191
192<p>A description of each parameter follows.</p></ol>
193
194<h5>image</h5>
195<ol><p>the image.</p></ol>
196
197<h5>exception</h5>
198<ol><p>return any errors or warnings in this structure.</p></ol>
199
200 </div>
201<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
202_8c.html" target="source" name="IsPaletteImage">IsPaletteImage</a></h2>
203<div class="doc-section">
204
205<p>IsPaletteImage() returns MagickTrue if the image is PseudoClass and has 256 unique colors or less.</p></ol>
206
207<p>The format of the IsPaletteImage method is:</p>
208
209<pre class="code">
210 MagickBooleanType IsPaletteImage(const Image *image,
211 ExceptionInfo *exception)
212</pre>
213
214<p>A description of each parameter follows.</p></ol>
215
216<h5>image</h5>
217<ol><p>the image.</p></ol>
218
219<h5>exception</h5>
220<ol><p>return any errors or warnings in this structure.</p></ol>
221
222 </div>
223<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]224_8c.html" target="source" name="MinMaxStretchImage">MinMaxStretchImage</a></h2>
225<div class="doc-section">
226
227<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>
228
229<p>If the adjustment values are both zero this function is equivelent to a perfect normalization (or autolevel) of the image.</p></ol>
230
231<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>
232
233<p>The 'SyncChannels' is turned on in the 'DefaultChannels' setting by default.</p></ol>
234
235<p>The format of the MinMaxStretchImage method is:</p>
236
237<pre class="code">
238 MagickBooleanType MinMaxStretchImage(Image *image,
239 const ChannelType channel, const double black_adjust,
240 const double white_adjust)
241</pre>
242
243<p>A description of each parameter follows:</p></ol>
244
245<h5>image</h5>
246<ol><p>The image to auto-level</p></ol>
247
248<h5>channel</h5>
249<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>
250
251<h5>black_adjust, white_adjust</h5>
252<ol><p>Move the Black/White Point inward from the minimum and maximum points by this color value.</p></ol>
253
254 </div>
cristy83543962009-10-16 19:04:28 +0000[diff] [blame]255<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
256_8c.html" target="source" name="GetNumberColors">GetNumberColors</a></h2>
257<div class="doc-section">
258
259<p>GetNumberColors() returns the number of unique colors in an image.</p></ol>
260
261<p>The format of the GetNumberColors method is:</p>
262
263<pre class="code">
264 unsigned long GetNumberColors(const Image *image,FILE *file,
265 ExceptionInfo *exception)
266</pre>
267
268<p>A description of each parameter follows.</p></ol>
269
270<h5>image</h5>
271<ol><p>the image.</p></ol>
272
273<h5>file</h5>
274<ol><p>Write a histogram of the color distribution to this file handle.</p></ol>
275
276<h5>exception</h5>
277<ol><p>return any errors or warnings in this structure.</p></ol>
278
279 </div>
280<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
281_8c.html" target="source" name="UniqueImageColors">UniqueImageColors</a></h2>
282<div class="doc-section">
283
284<p>UniqueImageColors() returns the unique colors of an image.</p></ol>
285
286<p>The format of the UniqueImageColors method is:</p>
287
288<pre class="code">
289 Image *UniqueImageColors(const Image *image,ExceptionInfo *exception)
290</pre>
291
292<p>A description of each parameter follows.</p></ol>
293
294<h5>image</h5>
295<ol><p>the image.</p></ol>
296
297<h5>exception</h5>
298<ol><p>return any errors or warnings in this structure.</p></ol>
299
300 </div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]301
302</div>
303
304<div id="linkbar">
305 <!-- <span id="linkbar-west">&nbsp;</span> -->
306 <span id="linkbar-center">
307 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> &bull;
cristy19156992010-03-04 17:04:59 +0000[diff] [blame]308 <a href="http://www.imagemagick.org/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">
cristy16af1cb2009-12-11 21:38:29 +0000[diff] [blame]313 <span id="footer-west">&copy; 1999-2010 ImageMagick Studio LLC</span>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]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>