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170
171<div class="main">
172
cristy83543962009-10-16 19:04:28 +0000173<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 +0000174
175<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
cristy83543962009-10-16 19:04:28 +0000176_8c.html" target="source" name="GetImageHistogram">GetImageHistogram</a></h2>
177<div class="doc-section">
178
179<p>GetImageHistogram() returns the unique colors in an image.</p></ol>
180
181<p>The format of the GetImageHistogram method is:</p>
182
183<pre class="code">
cristybb503372010-05-27 20:51:26 +0000184 size_t GetImageHistogram(const Image *image,
185 size_t *number_colors,ExceptionInfo *exception)
cristy83543962009-10-16 19:04:28 +0000186</pre>
187
188<p>A description of each parameter follows.</p></ol>
189
190<h5>image</h5>
191<ol><p>the image.</p></ol>
192
193<h5>file</h5>
194<ol><p>Write a histogram of the color distribution to this file handle.</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="IsHistogramImage">IsHistogramImage</a></h2>
202<div class="doc-section">
203
204<p>IsHistogramImage() returns MagickTrue if the image has 1024 unique colors or less.</p></ol>
205
206<p>The format of the IsHistogramImage method is:</p>
207
208<pre class="code">
209 MagickBooleanType IsHistogramImage(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
223_8c.html" target="source" name="IsPaletteImage">IsPaletteImage</a></h2>
224<div class="doc-section">
225
226<p>IsPaletteImage() returns MagickTrue if the image is PseudoClass and has 256 unique colors or less.</p></ol>
227
228<p>The format of the IsPaletteImage method is:</p>
229
230<pre class="code">
231 MagickBooleanType IsPaletteImage(const Image *image,
232 ExceptionInfo *exception)
233</pre>
234
235<p>A description of each parameter follows.</p></ol>
236
237<h5>image</h5>
238<ol><p>the image.</p></ol>
239
240<h5>exception</h5>
241<ol><p>return any errors or warnings in this structure.</p></ol>
242
243 </div>
244<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
cristy3ed852e2009-09-05 21:47:34 +0000245_8c.html" target="source" name="MinMaxStretchImage">MinMaxStretchImage</a></h2>
246<div class="doc-section">
247
248<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>
249
250<p>If the adjustment values are both zero this function is equivelent to a perfect normalization (or autolevel) of the image.</p></ol>
251
252<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>
253
cristy031b7a82010-04-08 00:33:24 +0000254<p>In the special case that only ONE value is found in a channel of the image that value is not stretched, that value is left as is.</p></ol>
255
cristy3ed852e2009-09-05 21:47:34 +0000256<p>The 'SyncChannels' is turned on in the 'DefaultChannels' setting by default.</p></ol>
257
258<p>The format of the MinMaxStretchImage method is:</p>
259
260<pre class="code">
261 MagickBooleanType MinMaxStretchImage(Image *image,
262 const ChannelType channel, const double black_adjust,
263 const double white_adjust)
264</pre>
265
266<p>A description of each parameter follows:</p></ol>
267
268<h5>image</h5>
269<ol><p>The image to auto-level</p></ol>
270
271<h5>channel</h5>
272<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>
273
274<h5>black_adjust, white_adjust</h5>
275<ol><p>Move the Black/White Point inward from the minimum and maximum points by this color value.</p></ol>
276
277 </div>
cristy83543962009-10-16 19:04:28 +0000278<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
279_8c.html" target="source" name="GetNumberColors">GetNumberColors</a></h2>
280<div class="doc-section">
281
282<p>GetNumberColors() returns the number of unique colors in an image.</p></ol>
283
284<p>The format of the GetNumberColors method is:</p>
285
286<pre class="code">
cristybb503372010-05-27 20:51:26 +0000287 size_t GetNumberColors(const Image *image,FILE *file,
cristy83543962009-10-16 19:04:28 +0000288 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>file</h5>
297<ol><p>Write a histogram of the color distribution to this file handle.</p></ol>
298
299<h5>exception</h5>
300<ol><p>return any errors or warnings in this structure.</p></ol>
301
302 </div>
303<h2><a href="http://www.imagemagick.org/api/MagickCore/histogram
304_8c.html" target="source" name="UniqueImageColors">UniqueImageColors</a></h2>
305<div class="doc-section">
306
307<p>UniqueImageColors() returns the unique colors of an image.</p></ol>
308
309<p>The format of the UniqueImageColors method is:</p>
310
311<pre class="code">
312 Image *UniqueImageColors(const Image *image,ExceptionInfo *exception)
313</pre>
314
315<p>A description of each parameter follows.</p></ol>
316
317<h5>image</h5>
318<ol><p>the image.</p></ol>
319
320<h5>exception</h5>
321<ol><p>return any errors or warnings in this structure.</p></ol>
322
323 </div>
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