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146
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150
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]151<p class="navigation-index">[<a href="#AcquirePixelCacheNexus">AcquirePixelCacheNexus</a> &bull; <a href="#GetAuthenticIndexQueue">GetAuthenticIndexQueue</a> &bull; <a href="#GetAuthenticPixelQueue">GetAuthenticPixelQueue</a> &bull; <a href="#GetAuthenticPixels">GetAuthenticPixels</a> &bull; <a href="#GetOneAuthenticPixel">GetOneAuthenticPixel</a> &bull; <a href="#GetOneVirtualMagickPixel">GetOneVirtualMagickPixel</a> &bull; <a href="#GetOneVirtualMethodPixel">GetOneVirtualMethodPixel</a> &bull; <a href="#GetOneVirtualPixel">GetOneVirtualPixel</a> &bull; <a href="#GetVirtualIndexQueue">GetVirtualIndexQueue</a> &bull; <a href="#VirtualPixelModulo">VirtualPixelModulo</a> &bull; <a href="#GetVirtualPixelQueue">GetVirtualPixelQueue</a> &bull; <a href="#GetVirtualPixels">GetVirtualPixels</a> &bull; <a href="#QueueAuthenticPixels">QueueAuthenticPixels</a> &bull; <a href="#SetPixelCacheVirtualMethod">SetPixelCacheVirtualMethod</a> &bull; <a href="#SyncAuthenticPixels">SyncAuthenticPixels</a>]</p>
152
153<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
154_8c.html" target="source" name="AcquirePixelCacheNexus">AcquirePixelCacheNexus</a></h2>
155<div class="doc-section">
156
157<p>AcquirePixelCacheNexus() allocates the NexusInfo structure.</p></ol>
158
159<p>The format of the AcquirePixelCacheNexus method is:</p>
160
161<pre class="code">
162 NexusInfo **AcquirePixelCacheNexus(const unsigned long number_threads)
163</pre>
164
165<p>A description of each parameter follows:</p></ol>
166
167<h5>number_threads</h5>
168<ol><p>the number of nexus threads.</p></ol>
169
170 </div>
171<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
172_8c.html" target="source" name="GetAuthenticIndexQueue">GetAuthenticIndexQueue</a></h2>
173<div class="doc-section">
174
175<p>GetAuthenticIndexQueue() returns the authentic black channel or the colormap indexes associated with the last call to QueueAuthenticPixels() or GetVirtualPixels(). NULL is returned if the black channel or colormap indexes are not available.</p></ol>
176
177<p>The format of the GetAuthenticIndexQueue() method is:</p>
178
179<pre class="code">
180 IndexPacket *GetAuthenticIndexQueue(const Image *image)
181</pre>
182
183<p>A description of each parameter follows:</p></ol>
184
185<h5>image</h5>
186<ol><p>the image.</p></ol>
187
188 </div>
189<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
190_8c.html" target="source" name="GetAuthenticPixelQueue">GetAuthenticPixelQueue</a></h2>
191<div class="doc-section">
192
193<p>GetAuthenticPixelQueue() returns the authentic pixels associated with the last call to QueueAuthenticPixels() or GetAuthenticPixels().</p></ol>
194
195<p>The format of the GetAuthenticPixelQueue() method is:</p>
196
197<pre class="code">
198 PixelPacket *GetAuthenticPixelQueue(const Image image)
199</pre>
200
201<p>A description of each parameter follows:</p></ol>
202
203<h5>image</h5>
204<ol><p>the image.</p></ol>
205
206 </div>
207<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
208_8c.html" target="source" name="GetAuthenticPixels">GetAuthenticPixels</a></h2>
209<div class="doc-section">
210
211<p>GetAuthenticPixels() obtains a pixel region for read/write access. If the region is successfully accessed, a pointer to a PixelPacket array representing the region is returned, otherwise NULL is returned.</p></ol>
212
213<p>The returned pointer may point to a temporary working copy of the pixels or it may point to the original pixels in memory. Performance is maximized if the selected region is part of one row, or one or more full rows, since then there is opportunity to access the pixels in-place (without a copy) if the image is in RAM, or in a memory-mapped file. The returned pointer should *never* be deallocated by the user.</p></ol>
214
215<p>Pixels accessed via the returned pointer represent a simple array of type PixelPacket. If the image type is CMYK or if the storage class is PseduoClass, call GetAuthenticIndexQueue() after invoking GetAuthenticPixels() to obtain the black color component or colormap indexes (of type IndexPacket) corresponding to the region. Once the PixelPacket (and/or IndexPacket) array has been updated, the changes must be saved back to the underlying image using SyncAuthenticPixels() or they may be lost.</p></ol>
216
217<p>The format of the GetAuthenticPixels() method is:</p>
218
219<pre class="code">
220 PixelPacket *GetAuthenticPixels(Image *image,const long x,const long y,
221 const unsigned long columns,const unsigned long rows,
222 ExceptionInfo *exception)
223</pre>
224
225<p>A description of each parameter follows:</p></ol>
226
227<h5>image</h5>
228<ol><p>the image.</p></ol>
229
230<h5>x,y,columns,rows</h5>
231<ol><p>These values define the perimeter of a region of pixels.</p></ol>
232
233<h5>exception</h5>
234<ol><p>return any errors or warnings in this structure.</p></ol>
235
236 </div>
237<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
238_8c.html" target="source" name="GetOneAuthenticPixel">GetOneAuthenticPixel</a></h2>
239<div class="doc-section">
240
241<p>GetOneAuthenticPixel() returns a single pixel at the specified (x,y) location. The image background color is returned if an error occurs.</p></ol>
242
243<p>The format of the GetOneAuthenticPixel() method is:</p>
244
245<pre class="code">
246 MagickBooleanType GetOneAuthenticPixel(const Image image,const long x,
247 const long y,PixelPacket *pixel,ExceptionInfo *exception)
248</pre>
249
250<p>A description of each parameter follows:</p></ol>
251
252<h5>image</h5>
253<ol><p>the image.</p></ol>
254
255<h5>x,y</h5>
256<ol><p>These values define the location of the pixel to return.</p></ol>
257
258<h5>pixel</h5>
259<ol><p>return a pixel at the specified (x,y) location.</p></ol>
260
261<h5>exception</h5>
262<ol><p>return any errors or warnings in this structure.</p></ol>
263
264 </div>
265<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
266_8c.html" target="source" name="GetOneVirtualMagickPixel">GetOneVirtualMagickPixel</a></h2>
267<div class="doc-section">
268
269<p>GetOneVirtualMagickPixel() returns a single pixel at the specified (x,y) location. The image background color is returned if an error occurs. If you plan to modify the pixel, use GetOneAuthenticPixel() instead.</p></ol>
270
271<p>The format of the GetOneVirtualMagickPixel() method is:</p>
272
273<pre class="code">
274 MagickBooleanType GetOneVirtualMagickPixel(const Image image,
275 const long x,const long y,MagickPixelPacket *pixel,
276 ExceptionInfo exception)
277</pre>
278
279<p>A description of each parameter follows:</p></ol>
280
281<h5>image</h5>
282<ol><p>the image.</p></ol>
283
284<h5>x,y</h5>
285<ol><p>these values define the location of the pixel to return.</p></ol>
286
287<h5>pixel</h5>
288<ol><p>return a pixel at the specified (x,y) location.</p></ol>
289
290<h5>exception</h5>
291<ol><p>return any errors or warnings in this structure.</p></ol>
292
293 </div>
294<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
295_8c.html" target="source" name="GetOneVirtualMethodPixel">GetOneVirtualMethodPixel</a></h2>
296<div class="doc-section">
297
298<p>GetOneVirtualMethodPixel() returns a single pixel at the specified (x,y) location as defined by specified pixel method. The image background color is returned if an error occurs. If you plan to modify the pixel, use GetOneAuthenticPixel() instead.</p></ol>
299
300<p>The format of the GetOneVirtualMethodPixel() method is:</p>
301
302<pre class="code">
303 MagickBooleanType GetOneVirtualMethodPixel(const Image image,
304 const VirtualPixelMethod virtual_pixel_method,const long x,
305 const long y,Pixelpacket *pixel,ExceptionInfo exception)
306</pre>
307
308<p>A description of each parameter follows:</p></ol>
309
310<h5>image</h5>
311<ol><p>the image.</p></ol>
312
313<h5>virtual_pixel_method</h5>
314<ol><p>the virtual pixel method.</p></ol>
315
316<h5>x,y</h5>
317<ol><p>These values define the location of the pixel to return.</p></ol>
318
319<h5>pixel</h5>
320<ol><p>return a pixel at the specified (x,y) location.</p></ol>
321
322<h5>exception</h5>
323<ol><p>return any errors or warnings in this structure.</p></ol>
324
325 </div>
326<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
327_8c.html" target="source" name="GetOneVirtualPixel">GetOneVirtualPixel</a></h2>
328<div class="doc-section">
329
330<p>GetOneVirtualPixel() returns a single virtual pixel at the specified (x,y) location. The image background color is returned if an error occurs. If you plan to modify the pixel, use GetOneAuthenticPixel() instead.</p></ol>
331
332<p>The format of the GetOneVirtualPixel() method is:</p>
333
334<pre class="code">
335 MagickBooleanType GetOneVirtualPixel(const Image image,const long x,
336 const long y,PixelPacket *pixel,ExceptionInfo exception)
337</pre>
338
339<p>A description of each parameter follows:</p></ol>
340
341<h5>image</h5>
342<ol><p>the image.</p></ol>
343
344<h5>x,y</h5>
345<ol><p>These values define the location of the pixel to return.</p></ol>
346
347<h5>pixel</h5>
348<ol><p>return a pixel at the specified (x,y) location.</p></ol>
349
350<h5>exception</h5>
351<ol><p>return any errors or warnings in this structure.</p></ol>
352
353 </div>
354<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
355_8c.html" target="source" name="GetVirtualIndexQueue">GetVirtualIndexQueue</a></h2>
356<div class="doc-section">
357
358<p>GetVirtualIndexQueue() returns the virtual black channel or the colormap indexes associated with the last call to QueueAuthenticPixels() or GetVirtualPixels(). NULL is returned if the black channel or colormap indexes are not available.</p></ol>
359
360<p>The format of the GetVirtualIndexQueue() method is:</p>
361
362<pre class="code">
363 const IndexPacket *GetVirtualIndexQueue(const Image *image)
364</pre>
365
366<p>A description of each parameter follows:</p></ol>
367
368<h5>image</h5>
369<ol><p>the image.</p></ol>
370
371 </div>
372<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
373_8c.html" target="source" name="VirtualPixelModulo">VirtualPixelModulo</a></h2>
374<div class="doc-section">
375
376<p>VirtualPixelModulo() computes the remainder of dividing offset by extent. It returns not only the quotient (tile the offset falls in) but also the positive remainer within that tile such that 0 <= remainder < extent. This method is essentially a ldiv() using a floored modulo division rather than the normal default truncated modulo division. </p>
377 </div>
378<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
379_8c.html" target="source" name="GetVirtualPixelQueue">GetVirtualPixelQueue</a></h2>
380<div class="doc-section">
381
382<p>GetVirtualPixelQueue() returns the virtual pixels associated with the last call to QueueAuthenticPixels() or GetVirtualPixels().</p></ol>
383
384<p>The format of the GetVirtualPixelQueue() method is:</p>
385
386<pre class="code">
387 const PixelPacket *GetVirtualPixelQueue(const Image image)
388</pre>
389
390<p>A description of each parameter follows:</p></ol>
391
392<h5>image</h5>
393<ol><p>the image.</p></ol>
394
395 </div>
396<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
397_8c.html" target="source" name="GetVirtualPixels">GetVirtualPixels</a></h2>
398<div class="doc-section">
399
400<p>GetVirtualPixels() returns an immutable pixel region. If the region is successfully accessed, a pointer to it is returned, otherwise NULL is returned. The returned pointer may point to a temporary working copy of the pixels or it may point to the original pixels in memory. Performance is maximized if the selected region is part of one row, or one or more full rows, since there is opportunity to access the pixels in-place (without a copy) if the image is in RAM, or in a memory-mapped file. The returned pointer should *never* be deallocated by the user.</p></ol>
401
402<p>Pixels accessed via the returned pointer represent a simple array of type PixelPacket. If the image type is CMYK or the storage class is PseudoClass, call GetAuthenticIndexQueue() after invoking GetAuthenticPixels() to access the black color component or to obtain the colormap indexes (of type IndexPacket) corresponding to the region.</p></ol>
403
404<p>If you plan to modify the pixels, use GetAuthenticPixels() instead.</p></ol>
405
406<p>Note, the GetVirtualPixels() and GetAuthenticPixels() methods are not thread- safe. In a threaded environment, use GetCacheViewVirtualPixels() or GetCacheViewAuthenticPixels() instead.</p></ol>
407
408<p>The format of the GetVirtualPixels() method is:</p>
409
410<pre class="code">
411 const PixelPacket *GetVirtualPixels(const Image *image,const long x,
412 const long y,const unsigned long columns,const unsigned long rows,
413 ExceptionInfo *exception)
414</pre>
415
416<p>A description of each parameter follows:</p></ol>
417
418<h5>image</h5>
419<ol><p>the image.</p></ol>
420
421<h5>x,y,columns,rows</h5>
422<ol><p>These values define the perimeter of a region of pixels.</p></ol>
423
424<h5>exception</h5>
425<ol><p>return any errors or warnings in this structure.</p></ol>
426
427 </div>
428<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
429_8c.html" target="source" name="QueueAuthenticPixels">QueueAuthenticPixels</a></h2>
430<div class="doc-section">
431
432<p>QueueAuthenticPixels() queues a mutable pixel region. If the region is successfully intialized a pointer to a PixelPacket array representing the region is returned, otherwise NULL is returned. The returned pointer may point to a temporary working buffer for the pixels or it may point to the final location of the pixels in memory.</p></ol>
433
434<p>Write-only access means that any existing pixel values corresponding to the region are ignored. This is useful if the initial image is being created from scratch, or if the existing pixel values are to be completely replaced without need to refer to their pre-existing values. The application is free to read and write the pixel buffer returned by QueueAuthenticPixels() any way it pleases. QueueAuthenticPixels() does not initialize the pixel array values. Initializing pixel array values is the application's responsibility.</p></ol>
435
436<p>Performance is maximized if the selected region is part of one row, or one or more full rows, since then there is opportunity to access the pixels in-place (without a copy) if the image is in RAM, or in a memory-mapped file. The returned pointer should *never* be deallocated by the user.</p></ol>
437
438<p>Pixels accessed via the returned pointer represent a simple array of type PixelPacket. If the image type is CMYK or the storage class is PseudoClass, call GetAuthenticIndexQueue() after invoking GetAuthenticPixels() to obtain the black color component or the colormap indexes (of type IndexPacket) corresponding to the region. Once the PixelPacket (and/or IndexPacket) array has been updated, the changes must be saved back to the underlying image using SyncAuthenticPixels() or they may be lost.</p></ol>
439
440<p>The format of the QueueAuthenticPixels() method is:</p>
441
442<pre class="code">
443 PixelPacket *QueueAuthenticPixels(Image *image,const long x,const long y,
444 const unsigned long columns,const unsigned long rows,
445 ExceptionInfo *exception)
446</pre>
447
448<p>A description of each parameter follows:</p></ol>
449
450<h5>image</h5>
451<ol><p>the image.</p></ol>
452
453<h5>x,y,columns,rows</h5>
454<ol><p>These values define the perimeter of a region of pixels.</p></ol>
455
456<h5>exception</h5>
457<ol><p>return any errors or warnings in this structure.</p></ol>
458
459 </div>
460<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
461_8c.html" target="source" name="SetPixelCacheVirtualMethod">SetPixelCacheVirtualMethod</a></h2>
462<div class="doc-section">
463
464<p>SetPixelCacheVirtualMethod() sets the "virtual pixels" method for the pixel cache and returns the previous setting. A virtual pixel is any pixel access that is outside the boundaries of the image cache.</p></ol>
465
466<p>The format of the SetPixelCacheVirtualMethod() method is:</p>
467
468<pre class="code">
469 VirtualPixelMethod SetPixelCacheVirtualMethod(const Image *image,
470 const VirtualPixelMethod virtual_pixel_method)
471</pre>
472
473<p>A description of each parameter follows:</p></ol>
474
475<h5>image</h5>
476<ol><p>the image.</p></ol>
477
478<h5>virtual_pixel_method</h5>
479<ol><p>choose the type of virtual pixel.</p></ol>
480
481 </div>
482<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
483_8c.html" target="source" name="SyncAuthenticPixels">SyncAuthenticPixels</a></h2>
484<div class="doc-section">
485
486<p>SyncAuthenticPixels() saves the image pixels to the in-memory or disk cache. The method returns MagickTrue if the pixel region is flushed, otherwise MagickFalse.</p></ol>
487
488<p>The format of the SyncAuthenticPixels() method is:</p>
489
490<pre class="code">
491 MagickBooleanType SyncAuthenticPixels(Image *image,
492 ExceptionInfo *exception)
493</pre>
494
495<p>A description of each parameter follows:</p></ol>
496
497<h5>image</h5>
498<ol><p>the image.</p></ol>
499
500<h5>exception</h5>
501<ol><p>return any errors or warnings in this structure.</p></ol>
502
503 </div>
cristyf3bb4782009-09-08 13:10:04 +0000[diff] [blame]504
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