granicus.if.org Git - imagemagick/blob - MagickCore/channel.c

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %                                                                             %
   6 %               CCCC  H   H   AAA   N   N  N   N  EEEEE   L                   %
   7 %              C      H   H  A   A  NN  N  NN  N  E       L                   %
   8 %              C      HHHHH  AAAAA  N N N  N N N  RRR     L                   %
   9 %              C      H   H  A   A  N  NN  N  NN  E       L                   %
  10 %               CCCC  H   H  A   A  N   N  N   N  EEEEE   LLLLL               %
  11 %                                                                             %
  12 %                                                                             %
  13 %                      MagickCore Image Channel Methods                       %
  14 %                                                                             %
  15 %                              Software Design                                %
  16 %                                John Cristy                                  %
  17 %                               December 2003                                 %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2013 ImageMagick Studio LLC, a non-profit organization      %
  21 %  dedicated to making software imaging solutions freely available.           %
  22 %                                                                             %
  23 %  You may not use this file except in compliance with the License.  You may  %
  24 %  obtain a copy of the License at                                            %
  25 %                                                                             %
  26 %    http://www.imagemagick.org/script/license.php                            %
  27 %                                                                             %
  28 %  Unless required by applicable law or agreed to in writing, software        %
  29 %  distributed under the License is distributed on an "AS IS" BASIS,          %
  30 %  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   %
  31 %  See the License for the specific language governing permissions and        %
  32 %  limitations under the License.                                             %
  33 %                                                                             %
  34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  35 %
  36 %
  37 %
  38 */
  39 \f
  40 /*
  41   Include declarations.
  42 */
  43 #include "MagickCore/studio.h"
  44 #include "MagickCore/colorspace-private.h"
  45 #include "MagickCore/image.h"
  46 #include "MagickCore/list.h"
  47 #include "MagickCore/log.h"
  48 #include "MagickCore/monitor.h"
  49 #include "MagickCore/monitor-private.h"
  50 #include "MagickCore/option.h"
  51 #include "MagickCore/pixel-accessor.h"
  52 #include "MagickCore/resource_.h"
  53 #include "MagickCore/string-private.h"
  54 #include "MagickCore/thread-private.h"
  55 #include "MagickCore/token.h"
  56 #include "MagickCore/utility.h"
  57 #include "MagickCore/version.h"
  58 \f
  59 /*
  60 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  61 %                                                                             %
  62 %                                                                             %
  63 %                                                                             %
  64 %     C h a n n e l F x I m a g e                                             %
  65 %                                                                             %
  66 %                                                                             %
  67 %                                                                             %
  68 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  69 %
  70 %  ChannelFxImage() applies a channel expression to the specified image.  The
  71 %  expression consists of one or more channels, either mnemonic or numeric (e.g.
  72 %  red, 1), separated by actions as follows:
  73 %
  74 %    <=>     exchange two channels (e.g. red<=>blue)
  75 %    =>      copy one channel to another channel (e.g. red=>green)
  76 %    =       assign a constant value to a channel (e.g. red=50%)
  77 %    ,       write new image channels in the specified order (e.g. red, green)
  78 %    |       add a new output image for the next set of channel operations
  79 %    ;       move to the next input image for the source of channel data
  80 %
  81 %  For example, to create 3 grayscale images from the red, green, and blue
  82 %  channels of an image, use:
  83 %
  84 %    -channel-fx "red; green; blue"
  85 %
  86 %  A channel without an operation symbol implies separate (i.e, semicolon).
  87 %
  88 %  The format of the ChannelFxImage method is:
  89 %
  90 %      Image *ChannelFxImage(const Image *image,const char *expression,
  91 %        ExceptionInfo *exception)
  92 %
  93 %  A description of each parameter follows:
  94 %
  95 %    o image: the image.
  96 %
  97 %    o expression: A channel expression.
  98 %
  99 %    o exception: return any errors or warnings in this structure.
 100 %
 101 */
 102
 103 typedef enum
 104 {
 105   ExtractChannelOp,
 106   AssignChannelOp,
 107   ExchangeChannelOp,
 108   TransferChannelOp
 109 } ChannelFx;
 110
 111 static inline size_t MagickMin(const size_t x,const size_t y)
 112 {
 113   if (x < y)
 114     return(x);
 115   return(y);
 116 }
 117
 118 static MagickBooleanType ChannelImage(Image *destination_image,
 119   const PixelChannel destination_channel,const ChannelFx channel_op,
 120   const Image *source_image,const PixelChannel source_channel,
 121   const Quantum pixel,ExceptionInfo *exception)
 122 {
 123   CacheView
 124     *source_view,
 125     *destination_view;
 126
 127   MagickBooleanType
 128     status;
 129
 130   size_t
 131     height,
 132     width;
 133
 134   ssize_t
 135     y;
 136
 137   status=MagickTrue;
 138   source_view=AcquireVirtualCacheView(source_image,exception);
 139   destination_view=AcquireAuthenticCacheView(destination_image,exception);
 140   height=MagickMin(source_image->rows,destination_image->rows);
 141   width=MagickMin(source_image->columns,destination_image->columns);
 142 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 143   #pragma omp parallel for schedule(static,4) shared(status) \
 144     magick_threads(source_image,source_image,height,1)
 145 #endif
 146   for (y=0; y < (ssize_t) height; y++)
 147   {
 148     PixelTrait
 149       destination_traits,
 150       source_traits;
 151
 152     register const Quantum
 153       *restrict p;
 154
 155     register Quantum
 156       *restrict q;
 157
 158     register ssize_t
 159       x;
 160
 161     if (status == MagickFalse)
 162       continue;
 163     p=GetCacheViewVirtualPixels(source_view,0,y,source_image->columns,1,
 164       exception);
 165     q=GetCacheViewAuthenticPixels(destination_view,0,y,
 166       destination_image->columns,1,exception);
 167     if ((p == (const Quantum *) NULL) || (q == (Quantum *) NULL))
 168       {
 169         status=MagickFalse;
 170         continue;
 171       }
 172     destination_traits=GetPixelChannelTraits(destination_image,
 173       destination_channel);
 174     source_traits=GetPixelChannelTraits(source_image,source_channel);
 175     if ((destination_traits == UndefinedPixelTrait) ||
 176         (source_traits == UndefinedPixelTrait))
 177       continue;
 178     for (x=0; x < (ssize_t) width; x++)
 179     {
 180       if (channel_op == AssignChannelOp)
 181         SetPixelChannel(destination_image,destination_channel,pixel,q);
 182       else
 183         SetPixelChannel(destination_image,destination_channel,
 184           GetPixelChannel(source_image,source_channel,p),q);
 185       p+=GetPixelChannels(source_image);
 186       q+=GetPixelChannels(destination_image);
 187     }
 188     if (SyncCacheViewAuthenticPixels(destination_view,exception) == MagickFalse)
 189       status=MagickFalse;
 190   }
 191   destination_view=DestroyCacheView(destination_view);
 192   source_view=DestroyCacheView(source_view);
 193   return(status);
 194 }
 195
 196 MagickExport Image *ChannelFxImage(const Image *image,const char *expression,
 197   ExceptionInfo *exception)
 198 {
 199 #define ChannelFxImageTag  "ChannelFx/Image"
 200
 201   ChannelFx
 202     channel_op;
 203
 204   ChannelType
 205     channel_mask;
 206
 207   char
 208     token[MaxTextExtent];
 209
 210   const char
 211     *p;
 212
 213   const Image
 214     *source_image;
 215
 216   double
 217     pixel;
 218
 219   Image
 220     *destination_image;
 221
 222   MagickBooleanType
 223     status;
 224
 225   PixelChannel
 226     source_channel,
 227     destination_channel;
 228
 229   ssize_t
 230     channels;
 231
 232   assert(image != (Image *) NULL);
 233   assert(image->signature == MagickSignature);
 234   if (image->debug != MagickFalse)
 235     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 236   assert(exception != (ExceptionInfo *) NULL);
 237   assert(exception->signature == MagickSignature);
 238   source_image=image;
 239   destination_image=CloneImage(source_image,0,0,MagickTrue,exception);
 240   if (destination_image == (Image *) NULL)
 241     return((Image *) NULL);
 242   if (expression == (const char *) NULL)
 243     return(destination_image);
 244   destination_channel=RedPixelChannel;
 245   channel_mask=UndefinedChannel;
 246   pixel=0.0;
 247   p=(char *) expression;
 248   GetMagickToken(p,&p,token);
 249   channel_op=ExtractChannelOp;
 250   for (channels=0; *token != '\0'; )
 251   {
 252     MagickBooleanType
 253       delete_channel;
 254
 255     ssize_t
 256       i;
 257
 258     /*
 259       Interpret channel expression.
 260     */
 261     delete_channel=MagickFalse;
 262     switch (*token)
 263     {
 264       case '~':
 265       {
 266         delete_channel=MagickTrue;
 267         GetMagickToken(p,&p,token);
 268         break;
 269       }
 270       case ',':
 271       {
 272         destination_channel=(PixelChannel) ((ssize_t) destination_channel+1);
 273         GetMagickToken(p,&p,token);
 274         break;
 275       }
 276       case '|':
 277       {
 278         if (GetNextImageInList(source_image) != (Image *) NULL)
 279           source_image=GetNextImageInList(source_image);
 280         else
 281           source_image=GetFirstImageInList(source_image);
 282         GetMagickToken(p,&p,token);
 283         break;
 284       }
 285       case ';':
 286       {
 287         Image
 288           *canvas;
 289
 290         SetPixelChannelMask(destination_image,channel_mask);
 291         if ((channel_op == ExtractChannelOp) && (channels == 1))
 292           (void) SetImageColorspace(destination_image,GRAYColorspace,exception);
 293         status=SetImageStorageClass(destination_image,DirectClass,exception);
 294         if (status == MagickFalse)
 295           {
 296             destination_image=DestroyImageList(destination_image);
 297             return(destination_image);
 298           }
 299         canvas=CloneImage(source_image,0,0,MagickTrue,exception);
 300         if (canvas == (Image *) NULL)
 301           {
 302             destination_image=DestroyImageList(destination_image);
 303             return(destination_image);
 304           }
 305         AppendImageToList(&destination_image,canvas);
 306         destination_image=GetLastImageInList(destination_image);
 307         GetMagickToken(p,&p,token);
 308         channels=0;
 309         destination_channel=RedPixelChannel;
 310         channel_mask=UndefinedChannel;
 311         break;
 312       }
 313       default:
 314         break;
 315     }
 316     i=ParsePixelChannelOption(token);
 317     if (i < 0)
 318       {
 319         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 320           "UnrecognizedChannelType","`%s'",token);
 321         destination_image=DestroyImageList(destination_image);
 322         return(destination_image);
 323       }
 324     source_channel=(PixelChannel) i;
 325     channel_op=ExtractChannelOp;
 326     GetMagickToken(p,&p,token);
 327     if (*token == '<')
 328       {
 329         channel_op=ExchangeChannelOp;
 330         GetMagickToken(p,&p,token);
 331       }
 332     if (*token == '=')
 333       {
 334         if (channel_op != ExchangeChannelOp)
 335           channel_op=AssignChannelOp;
 336         GetMagickToken(p,&p,token);
 337       }
 338     if (*token == '>')
 339       {
 340         if (channel_op != ExchangeChannelOp)
 341           channel_op=TransferChannelOp;
 342         GetMagickToken(p,&p,token);
 343       }
 344     switch (channel_op)
 345     {
 346       case AssignChannelOp:
 347       {
 348         pixel=StringToDoubleInterval(token,(double) QuantumRange+1.0);
 349         GetMagickToken(p,&p,token);
 350         break;
 351       }
 352       case ExchangeChannelOp:
 353       case TransferChannelOp:
 354       {
 355         i=ParsePixelChannelOption(token);
 356         if (i < 0)
 357           {
 358             (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 359               "UnrecognizedChannelType","`%s'",token);
 360             destination_image=DestroyImageList(destination_image);
 361             return(destination_image);
 362           }
 363         destination_channel=(PixelChannel) i;
 364         switch (destination_channel)
 365         {
 366           case AlphaPixelChannel:
 367           {
 368             destination_image->alpha_trait=BlendPixelTrait;
 369             break;
 370           }
 371           case ReadMaskPixelChannel:
 372           {
 373             destination_image->read_mask=MagickTrue;
 374             break;
 375           }
 376           case WriteMaskPixelChannel:
 377           {
 378             destination_image->write_mask=MagickTrue;
 379             break;
 380           }
 381           default:
 382             break;
 383         }
 384         channel_mask=(ChannelType) (channel_mask | ParseChannelOption(token));
 385         if (((channels >= 1)  || (destination_channel >= 1)) &&
 386             (IsGrayColorspace(destination_image->colorspace) != MagickFalse))
 387           (void) SetImageColorspace(destination_image,sRGBColorspace,exception);
 388         if (i >= (ssize_t) GetPixelChannels(destination_image))
 389           (void) SetPixelMetaChannels(destination_image,(size_t) (i-
 390             GetPixelChannels(destination_image)+1),exception);
 391         GetMagickToken(p,&p,token);
 392         break;
 393       }
 394       default:
 395         break;
 396     }
 397     status=ChannelImage(destination_image,destination_channel,channel_op,
 398       source_image,source_channel,ClampToQuantum(pixel),exception);
 399     if (status == MagickFalse)
 400       {
 401         destination_image=DestroyImageList(destination_image);
 402         break;
 403       }
 404     channels++;
 405     if (channel_op == ExchangeChannelOp)
 406       {
 407         status=ChannelImage(destination_image,source_channel,channel_op,
 408           source_image,destination_channel,ClampToQuantum(pixel),exception);
 409         if (status == MagickFalse)
 410           {
 411             destination_image=DestroyImageList(destination_image);
 412             break;
 413           }
 414         channels++;
 415       }
 416     switch (channel_op)
 417     {
 418       case ExtractChannelOp:
 419       {
 420         if (delete_channel == MagickFalse)
 421           channel_mask=(ChannelType) (channel_mask &~
 422             (1 << destination_channel));
 423         else
 424           channel_mask=(ChannelType) (channel_mask |
 425             (1 << destination_channel));
 426         destination_channel=(PixelChannel) (destination_channel+1);
 427         break;
 428       }
 429       default:
 430         break;
 431     }
 432     status=SetImageProgress(source_image,ChannelFxImageTag,p-expression,
 433       strlen(expression));
 434     if (status == MagickFalse)
 435       break;
 436   }
 437   SetPixelChannelMask(destination_image,channel_mask);
 438   if ((channel_op == ExtractChannelOp) && (channels == 1))
 439     (void) SetImageColorspace(destination_image,GRAYColorspace,exception);
 440   status=SetImageStorageClass(destination_image,DirectClass,exception);
 441   if (status == MagickFalse)
 442     {
 443       destination_image=GetLastImageInList(destination_image);
 444       return((Image *) NULL);
 445     }
 446   return(GetFirstImageInList(destination_image));
 447 }
 448 \f
 449 /*
 450 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 451 %                                                                             %
 452 %                                                                             %
 453 %                                                                             %
 454 %     C o m b i n e I m a g e s                                               %
 455 %                                                                             %
 456 %                                                                             %
 457 %                                                                             %
 458 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 459 %
 460 %  CombineImages() combines one or more images into a single image.  The
 461 %  grayscale value of the pixels of each image in the sequence is assigned in
 462 %  order to the specified channels of the combined image.   The typical
 463 %  ordering would be image 1 => Red, 2 => Green, 3 => Blue, etc.
 464 %
 465 %  The format of the CombineImages method is:
 466 %
 467 %      Image *CombineImages(const Image *images,const ColorspaceType colorspace,
 468 %        ExceptionInfo *exception)
 469 %
 470 %  A description of each parameter follows:
 471 %
 472 %    o images: the image sequence.
 473 %
 474 %    o colorspace: the image colorspace.
 475 %
 476 %    o exception: return any errors or warnings in this structure.
 477 %
 478 */
 479 MagickExport Image *CombineImages(const Image *image,
 480   const ColorspaceType colorspace,ExceptionInfo *exception)
 481 {
 482 #define CombineImageTag  "Combine/Image"
 483
 484   CacheView
 485     *combine_view;
 486
 487   Image
 488     *combine_image;
 489
 490   MagickBooleanType
 491     status;
 492
 493   MagickOffsetType
 494     progress;
 495
 496   ssize_t
 497     y;
 498
 499   /*
 500     Ensure the image are the same size.
 501   */
 502   assert(image != (const Image *) NULL);
 503   assert(image->signature == MagickSignature);
 504   if (image->debug != MagickFalse)
 505     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 506   assert(exception != (ExceptionInfo *) NULL);
 507   assert(exception->signature == MagickSignature);
 508   combine_image=CloneImage(image,0,0,MagickTrue,exception);
 509   if (combine_image == (Image *) NULL)
 510     return((Image *) NULL);
 511   if (SetImageStorageClass(combine_image,DirectClass,exception) == MagickFalse)
 512     {
 513       combine_image=DestroyImage(combine_image);
 514       return((Image *) NULL);
 515     }
 516   (void) SetImageColorspace(combine_image,colorspace,exception);
 517   if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
 518     combine_image->alpha_trait=BlendPixelTrait;
 519   /*
 520     Combine images.
 521   */
 522   status=MagickTrue;
 523   progress=0;
 524   combine_view=AcquireAuthenticCacheView(combine_image,exception);
 525   for (y=0; y < (ssize_t) combine_image->rows; y++)
 526   {
 527     CacheView
 528       *image_view;
 529
 530     const Image
 531       *next;
 532
 533     Quantum
 534       *pixels;
 535
 536     register const Quantum
 537       *restrict p;
 538
 539     register Quantum
 540       *restrict q;
 541
 542     register ssize_t
 543       i;
 544
 545     if (status == MagickFalse)
 546       continue;
 547     pixels=GetCacheViewAuthenticPixels(combine_view,0,y,combine_image->columns,
 548       1,exception);
 549     if (pixels == (Quantum *) NULL)
 550       {
 551         status=MagickFalse;
 552         continue;
 553       }
 554     next=image;
 555     for (i=0; i < (ssize_t) GetPixelChannels(combine_image); i++)
 556     {
 557       register ssize_t
 558         x;
 559
 560       PixelChannel channel=GetPixelChannelChannel(combine_image,i);
 561       PixelTrait traits=GetPixelChannelTraits(combine_image,channel);
 562       if (traits == UndefinedPixelTrait)
 563         continue;
 564       if (next == (Image *) NULL)
 565         continue;
 566       image_view=AcquireVirtualCacheView(next,exception);
 567       p=GetCacheViewVirtualPixels(image_view,0,y,next->columns,1,exception);
 568       if (p == (const Quantum *) NULL)
 569         continue;
 570       q=pixels;
 571       for (x=0; x < (ssize_t) combine_image->columns; x++)
 572       {
 573         if (x < (ssize_t) next->columns)
 574           {
 575             q[i]=GetPixelGray(next,p);
 576             p+=GetPixelChannels(next);
 577           }
 578         q+=GetPixelChannels(combine_image);
 579       }
 580       image_view=DestroyCacheView(image_view);
 581       next=GetNextImageInList(next);
 582     }
 583     if (SyncCacheViewAuthenticPixels(combine_view,exception) == MagickFalse)
 584       status=MagickFalse;
 585     if (image->progress_monitor != (MagickProgressMonitor) NULL)
 586       {
 587         MagickBooleanType
 588           proceed;
 589
 590         proceed=SetImageProgress(image,CombineImageTag,progress++,
 591           combine_image->rows);
 592         if (proceed == MagickFalse)
 593           status=MagickFalse;
 594       }
 595   }
 596   combine_view=DestroyCacheView(combine_view);
 597   if (status == MagickFalse)
 598     combine_image=DestroyImage(combine_image);
 599   return(combine_image);
 600 }
 601 \f
 602 /*
 603 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 604 %                                                                             %
 605 %                                                                             %
 606 %                                                                             %
 607 %     S e p a r a t e I m a g e                                               %
 608 %                                                                             %
 609 %                                                                             %
 610 %                                                                             %
 611 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 612 %
 613 %  SeparateImage() separates a channel from the image and returns it as a
 614 %  grayscale image.
 615 %
 616 %  The format of the SeparateImage method is:
 617 %
 618 %      Image *SeparateImage(const Image *image,const ChannelType channel,
 619 %        ExceptionInfo *exception)
 620 %
 621 %  A description of each parameter follows:
 622 %
 623 %    o image: the image.
 624 %
 625 %    o channel: the image channel.
 626 %
 627 %    o exception: return any errors or warnings in this structure.
 628 %
 629 */
 630 MagickExport Image *SeparateImage(const Image *image,
 631   const ChannelType channel_type,ExceptionInfo *exception)
 632 {
 633 #define GetChannelBit(mask,bit)  (((size_t) (mask) >> (size_t) (bit)) & 0x01)
 634 #define SeparateImageTag  "Separate/Image"
 635
 636   CacheView
 637     *image_view,
 638     *separate_view;
 639
 640   Image
 641     *separate_image;
 642
 643   MagickBooleanType
 644     status;
 645
 646   MagickOffsetType
 647     progress;
 648
 649   ssize_t
 650     y;
 651
 652   /*
 653     Initialize separate image attributes.
 654   */
 655   assert(image != (Image *) NULL);
 656   assert(image->signature == MagickSignature);
 657   if (image->debug != MagickFalse)
 658     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 659   assert(exception != (ExceptionInfo *) NULL);
 660   assert(exception->signature == MagickSignature);
 661   separate_image=CloneImage(image,image->columns,image->rows,MagickTrue,
 662     exception);
 663   if (separate_image == (Image *) NULL)
 664     return((Image *) NULL);
 665   if (SetImageStorageClass(separate_image,DirectClass,exception) == MagickFalse)
 666     {
 667       separate_image=DestroyImage(separate_image);
 668       return((Image *) NULL);
 669     }
 670   (void) SetImageColorspace(separate_image,GRAYColorspace,exception);
 671   separate_image->alpha_trait=UndefinedPixelTrait;
 672   /*
 673     Separate image.
 674   */
 675   status=MagickTrue;
 676   progress=0;
 677   image_view=AcquireVirtualCacheView(image,exception);
 678   separate_view=AcquireAuthenticCacheView(separate_image,exception);
 679 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 680   #pragma omp parallel for schedule(static,4) shared(progress,status) \
 681     magick_threads(image,image,image->rows,1)
 682 #endif
 683   for (y=0; y < (ssize_t) image->rows; y++)
 684   {
 685     register const Quantum
 686       *restrict p;
 687
 688     register Quantum
 689       *restrict q;
 690
 691     register ssize_t
 692       x;
 693
 694     if (status == MagickFalse)
 695       continue;
 696     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 697     q=QueueCacheViewAuthenticPixels(separate_view,0,y,separate_image->columns,1,
 698       exception);
 699     if ((p == (const Quantum *) NULL) || (q == (Quantum *) NULL))
 700       {
 701         status=MagickFalse;
 702         continue;
 703       }
 704     for (x=0; x < (ssize_t) image->columns; x++)
 705     {
 706       register ssize_t
 707         i;
 708
 709       if (GetPixelReadMask(image,p) == 0)
 710         {
 711           p+=GetPixelChannels(image);
 712           q+=GetPixelChannels(separate_image);
 713           continue;
 714         }
 715       SetPixelChannel(separate_image,GrayPixelChannel,0,q);
 716       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 717       {
 718         PixelChannel channel=GetPixelChannelChannel(image,i);
 719         PixelTrait traits=GetPixelChannelTraits(image,channel);
 720         if ((traits == UndefinedPixelTrait) ||
 721             (GetChannelBit(channel_type,channel) == 0))
 722           continue;
 723         SetPixelChannel(separate_image,GrayPixelChannel,p[i],q);
 724       }
 725       p+=GetPixelChannels(image);
 726       q+=GetPixelChannels(separate_image);
 727     }
 728     if (SyncCacheViewAuthenticPixels(separate_view,exception) == MagickFalse)
 729       status=MagickFalse;
 730     if (image->progress_monitor != (MagickProgressMonitor) NULL)
 731       {
 732         MagickBooleanType
 733           proceed;
 734
 735 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 736         #pragma omp critical (MagickCore_SeparateImage)
 737 #endif
 738         proceed=SetImageProgress(image,SeparateImageTag,progress++,image->rows);
 739         if (proceed == MagickFalse)
 740           status=MagickFalse;
 741       }
 742   }
 743   separate_view=DestroyCacheView(separate_view);
 744   image_view=DestroyCacheView(image_view);
 745   if (status == MagickFalse)
 746     separate_image=DestroyImage(separate_image);
 747   return(separate_image);
 748 }
 749 \f
 750 /*
 751 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 752 %                                                                             %
 753 %                                                                             %
 754 %                                                                             %
 755 %     S e p a r a t e I m a g e s                                             %
 756 %                                                                             %
 757 %                                                                             %
 758 %                                                                             %
 759 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 760 %
 761 %  SeparateImages() returns a separate grayscale image for each channel
 762 %  specified.
 763 %
 764 %  The format of the SeparateImages method is:
 765 %
 766 %      Image *SeparateImages(const Image *image,ExceptionInfo *exception)
 767 %
 768 %  A description of each parameter follows:
 769 %
 770 %    o image: the image.
 771 %
 772 %    o exception: return any errors or warnings in this structure.
 773 %
 774 */
 775 MagickExport Image *SeparateImages(const Image *image,ExceptionInfo *exception)
 776 {
 777   Image
 778     *images,
 779     *separate_image;
 780
 781   register ssize_t
 782     i;
 783
 784   assert(image != (Image *) NULL);
 785   assert(image->signature == MagickSignature);
 786   if (image->debug != MagickFalse)
 787     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 788   images=NewImageList();
 789   for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 790   {
 791     PixelChannel channel=GetPixelChannelChannel(image,i);
 792     PixelTrait traits=GetPixelChannelTraits(image,channel);
 793     if ((traits == UndefinedPixelTrait) ||
 794         ((traits & UpdatePixelTrait) == 0))
 795       continue;
 796     separate_image=SeparateImage(image,(ChannelType) (1 << channel),exception);
 797     if (separate_image != (Image *) NULL)
 798       AppendImageToList(&images,separate_image);
 799   }
 800   if (images == (Image *) NULL)
 801     images=SeparateImage(image,UndefinedChannel,exception);
 802   return(images);
 803 }