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

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %                                                                             %
   6 %       TTTTT  H   H  RRRR   EEEEE  SSSSS  H   H   OOO   L      DDDD          %
   7 %         T    H   H  R   R  E      SS     H   H  O   O  L      D   D         %
   8 %         T    HHHHH  RRRR   EEE     SSS   HHHHH  O   O  L      D   D         %
   9 %         T    H   H  R R    E         SS  H   H  O   O  L      D   D         %
  10 %         T    H   H  R  R   EEEEE  SSSSS  H   H   OOO   LLLLL  DDDD          %
  11 %                                                                             %
  12 %                                                                             %
  13 %                      MagickCore Image Threshold Methods                     %
  14 %                                                                             %
  15 %                               Software Design                               %
  16 %                                    Cristy                                   %
  17 %                                 October 1996                                %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2017 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 %    https://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/property.h"
  45 #include "MagickCore/blob.h"
  46 #include "MagickCore/cache-view.h"
  47 #include "MagickCore/color.h"
  48 #include "MagickCore/color-private.h"
  49 #include "MagickCore/colormap.h"
  50 #include "MagickCore/colorspace.h"
  51 #include "MagickCore/colorspace-private.h"
  52 #include "MagickCore/configure.h"
  53 #include "MagickCore/constitute.h"
  54 #include "MagickCore/decorate.h"
  55 #include "MagickCore/draw.h"
  56 #include "MagickCore/enhance.h"
  57 #include "MagickCore/exception.h"
  58 #include "MagickCore/exception-private.h"
  59 #include "MagickCore/effect.h"
  60 #include "MagickCore/fx.h"
  61 #include "MagickCore/gem.h"
  62 #include "MagickCore/geometry.h"
  63 #include "MagickCore/image-private.h"
  64 #include "MagickCore/list.h"
  65 #include "MagickCore/log.h"
  66 #include "MagickCore/memory_.h"
  67 #include "MagickCore/monitor.h"
  68 #include "MagickCore/monitor-private.h"
  69 #include "MagickCore/montage.h"
  70 #include "MagickCore/option.h"
  71 #include "MagickCore/pixel-accessor.h"
  72 #include "MagickCore/pixel-private.h"
  73 #include "MagickCore/quantize.h"
  74 #include "MagickCore/quantum.h"
  75 #include "MagickCore/random_.h"
  76 #include "MagickCore/random-private.h"
  77 #include "MagickCore/resize.h"
  78 #include "MagickCore/resource_.h"
  79 #include "MagickCore/segment.h"
  80 #include "MagickCore/shear.h"
  81 #include "MagickCore/signature-private.h"
  82 #include "MagickCore/string_.h"
  83 #include "MagickCore/string-private.h"
  84 #include "MagickCore/thread-private.h"
  85 #include "MagickCore/threshold.h"
  86 #include "MagickCore/token.h"
  87 #include "MagickCore/transform.h"
  88 #include "MagickCore/xml-tree.h"
  89 #include "MagickCore/xml-tree-private.h"
  90 \f
  91 /*
  92   Define declarations.
  93 */
  94 #define ThresholdsFilename  "thresholds.xml"
  95 \f
  96 /*
  97   Typedef declarations.
  98 */
  99 struct _ThresholdMap
 100 {
 101   char
 102     *map_id,
 103     *description;
 104
 105   size_t
 106     width,
 107     height;
 108
 109   ssize_t
 110     divisor,
 111     *levels;
 112 };
 113 \f
 114 /*
 115   Static declarations.
 116 */
 117 static const char
 118   *MinimalThresholdMap =
 119     "<?xml version=\"1.0\"?>"
 120     "<thresholds>"
 121     "  <threshold map=\"threshold\" alias=\"1x1\">"
 122     "    <description>Threshold 1x1 (non-dither)</description>"
 123     "    <levels width=\"1\" height=\"1\" divisor=\"2\">"
 124     "        1"
 125     "    </levels>"
 126     "  </threshold>"
 127     "  <threshold map=\"checks\" alias=\"2x1\">"
 128     "    <description>Checkerboard 2x1 (dither)</description>"
 129     "    <levels width=\"2\" height=\"2\" divisor=\"3\">"
 130     "       1 2"
 131     "       2 1"
 132     "    </levels>"
 133     "  </threshold>"
 134     "</thresholds>";
 135 \f
 136 /*
 137   Forward declarations.
 138 */
 139 static ThresholdMap
 140   *GetThresholdMapFile(const char *,const char *,const char *,ExceptionInfo *);
 141 \f
 142 /*
 143 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 144 %                                                                             %
 145 %                                                                             %
 146 %                                                                             %
 147 %     A d a p t i v e T h r e s h o l d I m a g e                             %
 148 %                                                                             %
 149 %                                                                             %
 150 %                                                                             %
 151 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 152 %
 153 %  AdaptiveThresholdImage() selects an individual threshold for each pixel
 154 %  based on the range of intensity values in its local neighborhood.  This
 155 %  allows for thresholding of an image whose global intensity histogram
 156 %  doesn't contain distinctive peaks.
 157 %
 158 %  The format of the AdaptiveThresholdImage method is:
 159 %
 160 %      Image *AdaptiveThresholdImage(const Image *image,const size_t width,
 161 %        const size_t height,const double bias,ExceptionInfo *exception)
 162 %
 163 %  A description of each parameter follows:
 164 %
 165 %    o image: the image.
 166 %
 167 %    o width: the width of the local neighborhood.
 168 %
 169 %    o height: the height of the local neighborhood.
 170 %
 171 %    o bias: the mean bias.
 172 %
 173 %    o exception: return any errors or warnings in this structure.
 174 %
 175 */
 176 MagickExport Image *AdaptiveThresholdImage(const Image *image,
 177   const size_t width,const size_t height,const double bias,
 178   ExceptionInfo *exception)
 179 {
 180 #define AdaptiveThresholdImageTag  "AdaptiveThreshold/Image"
 181
 182   CacheView
 183     *image_view,
 184     *threshold_view;
 185
 186   Image
 187     *threshold_image;
 188
 189   MagickBooleanType
 190     status;
 191
 192   MagickOffsetType
 193     progress;
 194
 195   MagickSizeType
 196     number_pixels;
 197
 198   ssize_t
 199     y;
 200
 201   /*
 202     Initialize threshold image attributes.
 203   */
 204   assert(image != (Image *) NULL);
 205   assert(image->signature == MagickCoreSignature);
 206   if (image->debug != MagickFalse)
 207     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 208   assert(exception != (ExceptionInfo *) NULL);
 209   assert(exception->signature == MagickCoreSignature);
 210   threshold_image=CloneImage(image,image->columns,image->rows,MagickTrue,
 211     exception);
 212   if (threshold_image == (Image *) NULL)
 213     return((Image *) NULL);
 214   status=SetImageStorageClass(threshold_image,DirectClass,exception);
 215   if (status == MagickFalse)
 216     {
 217       threshold_image=DestroyImage(threshold_image);
 218       return((Image *) NULL);
 219     }
 220   /*
 221     Threshold image.
 222   */
 223   status=MagickTrue;
 224   progress=0;
 225   number_pixels=(MagickSizeType) width*height;
 226   image_view=AcquireVirtualCacheView(image,exception);
 227   threshold_view=AcquireAuthenticCacheView(threshold_image,exception);
 228 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 229   #pragma omp parallel for schedule(static,4) shared(progress,status) \
 230     magick_threads(image,threshold_image,image->rows,1)
 231 #endif
 232   for (y=0; y < (ssize_t) image->rows; y++)
 233   {
 234     double
 235       channel_bias[MaxPixelChannels],
 236       channel_sum[MaxPixelChannels];
 237
 238     register const Quantum
 239       *magick_restrict p,
 240       *magick_restrict pixels;
 241
 242     register Quantum
 243       *magick_restrict q;
 244
 245     register ssize_t
 246       i,
 247       x;
 248
 249     ssize_t
 250       center,
 251       u,
 252       v;
 253
 254     if (status == MagickFalse)
 255       continue;
 256     p=GetCacheViewVirtualPixels(image_view,-((ssize_t) width/2L),y-(ssize_t)
 257       (height/2L),image->columns+width,height,exception);
 258     q=QueueCacheViewAuthenticPixels(threshold_view,0,y,threshold_image->columns,
 259       1,exception);
 260     if ((p == (const Quantum *) NULL) || (q == (Quantum *) NULL))
 261       {
 262         status=MagickFalse;
 263         continue;
 264       }
 265     center=(ssize_t) GetPixelChannels(image)*(image->columns+width)*(height/2L)+
 266       GetPixelChannels(image)*(width/2);
 267     for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 268     {
 269       PixelChannel channel=GetPixelChannelChannel(image,i);
 270       PixelTrait traits=GetPixelChannelTraits(image,channel);
 271       PixelTrait threshold_traits=GetPixelChannelTraits(threshold_image,
 272         channel);
 273       if ((traits == UndefinedPixelTrait) ||
 274           (threshold_traits == UndefinedPixelTrait))
 275         continue;
 276       if (((threshold_traits & CopyPixelTrait) != 0) ||
 277           (GetPixelWriteMask(image,p) == 0))
 278         {
 279           SetPixelChannel(threshold_image,channel,p[center+i],q);
 280           continue;
 281         }
 282       pixels=p;
 283       channel_bias[channel]=0.0;
 284       channel_sum[channel]=0.0;
 285       for (v=0; v < (ssize_t) height; v++)
 286       {
 287         for (u=0; u < (ssize_t) width; u++)
 288         {
 289           if (u == (ssize_t) (width-1))
 290             channel_bias[channel]+=pixels[i];
 291           channel_sum[channel]+=pixels[i];
 292           pixels+=GetPixelChannels(image);
 293         }
 294         pixels+=GetPixelChannels(image)*image->columns;
 295       }
 296     }
 297     for (x=0; x < (ssize_t) image->columns; x++)
 298     {
 299       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 300       {
 301         double
 302           mean;
 303
 304         PixelChannel channel=GetPixelChannelChannel(image,i);
 305         PixelTrait traits=GetPixelChannelTraits(image,channel);
 306         PixelTrait threshold_traits=GetPixelChannelTraits(threshold_image,
 307           channel);
 308         if ((traits == UndefinedPixelTrait) ||
 309             (threshold_traits == UndefinedPixelTrait))
 310           continue;
 311         if (((threshold_traits & CopyPixelTrait) != 0) ||
 312             (GetPixelWriteMask(image,p) == 0))
 313           {
 314             SetPixelChannel(threshold_image,channel,p[center+i],q);
 315             continue;
 316           }
 317         channel_sum[channel]-=channel_bias[channel];
 318         channel_bias[channel]=0.0;
 319         pixels=p;
 320         for (v=0; v < (ssize_t) height; v++)
 321         {
 322           channel_bias[channel]+=pixels[i];
 323           pixels+=(width-1)*GetPixelChannels(image);
 324           channel_sum[channel]+=pixels[i];
 325           pixels+=GetPixelChannels(image)*(image->columns+1);
 326         }
 327         mean=(double) (channel_sum[channel]/number_pixels+bias);
 328         SetPixelChannel(threshold_image,channel,(Quantum) ((double)
 329           p[center+i] <= mean ? 0 : QuantumRange),q);
 330       }
 331       p+=GetPixelChannels(image);
 332       q+=GetPixelChannels(threshold_image);
 333     }
 334     if (SyncCacheViewAuthenticPixels(threshold_view,exception) == MagickFalse)
 335       status=MagickFalse;
 336     if (image->progress_monitor != (MagickProgressMonitor) NULL)
 337       {
 338         MagickBooleanType
 339           proceed;
 340
 341 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 342         #pragma omp critical (MagickCore_AdaptiveThresholdImage)
 343 #endif
 344         proceed=SetImageProgress(image,AdaptiveThresholdImageTag,progress++,
 345           image->rows);
 346         if (proceed == MagickFalse)
 347           status=MagickFalse;
 348       }
 349   }
 350   threshold_image->type=image->type;
 351   threshold_view=DestroyCacheView(threshold_view);
 352   image_view=DestroyCacheView(image_view);
 353   if (status == MagickFalse)
 354     threshold_image=DestroyImage(threshold_image);
 355   return(threshold_image);
 356 }
 357 \f
 358 /*
 359 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 360 %                                                                             %
 361 %                                                                             %
 362 %                                                                             %
 363 %     B i l e v e l I m a g e                                                 %
 364 %                                                                             %
 365 %                                                                             %
 366 %                                                                             %
 367 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 368 %
 369 %  BilevelImage() changes the value of individual pixels based on the
 370 %  intensity of each pixel channel.  The result is a high-contrast image.
 371 %
 372 %  More precisely each channel value of the image is 'thresholded' so that if
 373 %  it is equal to or less than the given value it is set to zero, while any
 374 %  value greater than that give is set to it maximum or QuantumRange.
 375 %
 376 %  This function is what is used to implement the "-threshold" operator for
 377 %  the command line API.
 378 %
 379 %  If the default channel setting is given the image is thresholded using just
 380 %  the gray 'intensity' of the image, rather than the individual channels.
 381 %
 382 %  The format of the BilevelImage method is:
 383 %
 384 %      MagickBooleanType BilevelImage(Image *image,const double threshold,
 385 %        ExceptionInfo *exception)
 386 %
 387 %  A description of each parameter follows:
 388 %
 389 %    o image: the image.
 390 %
 391 %    o threshold: define the threshold values.
 392 %
 393 %    o exception: return any errors or warnings in this structure.
 394 %
 395 %  Aside: You can get the same results as operator using LevelImages()
 396 %  with the 'threshold' value for both the black_point and the white_point.
 397 %
 398 */
 399 MagickExport MagickBooleanType BilevelImage(Image *image,const double threshold,
 400   ExceptionInfo *exception)
 401 {
 402 #define ThresholdImageTag  "Threshold/Image"
 403
 404   CacheView
 405     *image_view;
 406
 407   MagickBooleanType
 408     status;
 409
 410   MagickOffsetType
 411     progress;
 412
 413   ssize_t
 414     y;
 415
 416   assert(image != (Image *) NULL);
 417   assert(image->signature == MagickCoreSignature);
 418   if (image->debug != MagickFalse)
 419     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 420   if (SetImageStorageClass(image,DirectClass,exception) == MagickFalse)
 421     return(MagickFalse);
 422   if (IsGrayColorspace(image->colorspace) != MagickFalse)
 423     (void) SetImageColorspace(image,sRGBColorspace,exception);
 424   /*
 425     Bilevel threshold image.
 426   */
 427   status=MagickTrue;
 428   progress=0;
 429   image_view=AcquireAuthenticCacheView(image,exception);
 430 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 431   #pragma omp parallel for schedule(static,4) shared(progress,status) \
 432     magick_threads(image,image,image->rows,1)
 433 #endif
 434   for (y=0; y < (ssize_t) image->rows; y++)
 435   {
 436     register ssize_t
 437       x;
 438
 439     register Quantum
 440       *magick_restrict q;
 441
 442     if (status == MagickFalse)
 443       continue;
 444     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
 445     if (q == (Quantum *) NULL)
 446       {
 447         status=MagickFalse;
 448         continue;
 449       }
 450     for (x=0; x < (ssize_t) image->columns; x++)
 451     {
 452       double
 453         pixel;
 454
 455       register ssize_t
 456         i;
 457
 458       if (GetPixelWriteMask(image,q) == 0)
 459         {
 460           q+=GetPixelChannels(image);
 461           continue;
 462         }
 463       pixel=GetPixelIntensity(image,q);
 464       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 465       {
 466         PixelChannel channel=GetPixelChannelChannel(image,i);
 467         PixelTrait traits=GetPixelChannelTraits(image,channel);
 468         if ((traits & UpdatePixelTrait) == 0)
 469           continue;
 470         if (image->channel_mask != DefaultChannels)
 471           pixel=(double) q[i];
 472         q[i]=(Quantum) (pixel <= threshold ? 0 : QuantumRange);
 473       }
 474       q+=GetPixelChannels(image);
 475     }
 476     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
 477       status=MagickFalse;
 478     if (image->progress_monitor != (MagickProgressMonitor) NULL)
 479       {
 480         MagickBooleanType
 481           proceed;
 482
 483 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 484         #pragma omp critical (MagickCore_BilevelImage)
 485 #endif
 486         proceed=SetImageProgress(image,ThresholdImageTag,progress++,
 487           image->rows);
 488         if (proceed == MagickFalse)
 489           status=MagickFalse;
 490       }
 491   }
 492   image_view=DestroyCacheView(image_view);
 493   return(status);
 494 }
 495 \f
 496 /*
 497 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 498 %                                                                             %
 499 %                                                                             %
 500 %                                                                             %
 501 %     B l a c k T h r e s h o l d I m a g e                                   %
 502 %                                                                             %
 503 %                                                                             %
 504 %                                                                             %
 505 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 506 %
 507 %  BlackThresholdImage() is like ThresholdImage() but forces all pixels below
 508 %  the threshold into black while leaving all pixels at or above the threshold
 509 %  unchanged.
 510 %
 511 %  The format of the BlackThresholdImage method is:
 512 %
 513 %      MagickBooleanType BlackThresholdImage(Image *image,
 514 %        const char *threshold,ExceptionInfo *exception)
 515 %
 516 %  A description of each parameter follows:
 517 %
 518 %    o image: the image.
 519 %
 520 %    o threshold: define the threshold value.
 521 %
 522 %    o exception: return any errors or warnings in this structure.
 523 %
 524 */
 525 MagickExport MagickBooleanType BlackThresholdImage(Image *image,
 526   const char *thresholds,ExceptionInfo *exception)
 527 {
 528 #define ThresholdImageTag  "Threshold/Image"
 529
 530   CacheView
 531     *image_view;
 532
 533   GeometryInfo
 534     geometry_info;
 535
 536   MagickBooleanType
 537     status;
 538
 539   MagickOffsetType
 540     progress;
 541
 542   PixelInfo
 543     threshold;
 544
 545   MagickStatusType
 546     flags;
 547
 548   ssize_t
 549     y;
 550
 551   assert(image != (Image *) NULL);
 552   assert(image->signature == MagickCoreSignature);
 553   if (image->debug != MagickFalse)
 554     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 555   if (thresholds == (const char *) NULL)
 556     return(MagickTrue);
 557   if (SetImageStorageClass(image,DirectClass,exception) == MagickFalse)
 558     return(MagickFalse);
 559   if (IsGrayColorspace(image->colorspace) != MagickFalse)
 560     (void) SetImageColorspace(image,sRGBColorspace,exception);
 561   GetPixelInfo(image,&threshold);
 562   flags=ParseGeometry(thresholds,&geometry_info);
 563   threshold.red=geometry_info.rho;
 564   threshold.green=geometry_info.rho;
 565   threshold.blue=geometry_info.rho;
 566   threshold.black=geometry_info.rho;
 567   threshold.alpha=100.0;
 568   if ((flags & SigmaValue) != 0)
 569     threshold.green=geometry_info.sigma;
 570   if ((flags & XiValue) != 0)
 571     threshold.blue=geometry_info.xi;
 572   if ((flags & PsiValue) != 0)
 573     threshold.alpha=geometry_info.psi;
 574   if (threshold.colorspace == CMYKColorspace)
 575     {
 576       if ((flags & PsiValue) != 0)
 577         threshold.black=geometry_info.psi;
 578       if ((flags & ChiValue) != 0)
 579         threshold.alpha=geometry_info.chi;
 580     }
 581   if ((flags & PercentValue) != 0)
 582     {
 583       threshold.red*=(MagickRealType) (QuantumRange/100.0);
 584       threshold.green*=(MagickRealType) (QuantumRange/100.0);
 585       threshold.blue*=(MagickRealType) (QuantumRange/100.0);
 586       threshold.black*=(MagickRealType) (QuantumRange/100.0);
 587       threshold.alpha*=(MagickRealType) (QuantumRange/100.0);
 588     }
 589   /*
 590     White threshold image.
 591   */
 592   status=MagickTrue;
 593   progress=0;
 594   image_view=AcquireAuthenticCacheView(image,exception);
 595 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 596   #pragma omp parallel for schedule(static,4) shared(progress,status) \
 597     magick_threads(image,image,image->rows,1)
 598 #endif
 599   for (y=0; y < (ssize_t) image->rows; y++)
 600   {
 601     register ssize_t
 602       x;
 603
 604     register Quantum
 605       *magick_restrict q;
 606
 607     if (status == MagickFalse)
 608       continue;
 609     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
 610     if (q == (Quantum *) NULL)
 611       {
 612         status=MagickFalse;
 613         continue;
 614       }
 615     for (x=0; x < (ssize_t) image->columns; x++)
 616     {
 617       double
 618         pixel;
 619
 620       register ssize_t
 621         i;
 622
 623       if (GetPixelWriteMask(image,q) == 0)
 624         {
 625           q+=GetPixelChannels(image);
 626           continue;
 627         }
 628       pixel=GetPixelIntensity(image,q);
 629       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 630       {
 631         PixelChannel channel=GetPixelChannelChannel(image,i);
 632         PixelTrait traits=GetPixelChannelTraits(image,channel);
 633         if ((traits & UpdatePixelTrait) == 0)
 634           continue;
 635         if (image->channel_mask != DefaultChannels)
 636           pixel=(double) q[i];
 637         if (pixel < GetPixelInfoChannel(&threshold,channel))
 638           q[i]=(Quantum) 0;
 639       }
 640       q+=GetPixelChannels(image);
 641     }
 642     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
 643       status=MagickFalse;
 644     if (image->progress_monitor != (MagickProgressMonitor) NULL)
 645       {
 646         MagickBooleanType
 647           proceed;
 648
 649 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 650         #pragma omp critical (MagickCore_BlackThresholdImage)
 651 #endif
 652         proceed=SetImageProgress(image,ThresholdImageTag,progress++,
 653           image->rows);
 654         if (proceed == MagickFalse)
 655           status=MagickFalse;
 656       }
 657   }
 658   image_view=DestroyCacheView(image_view);
 659   return(status);
 660 }
 661 \f
 662 /*
 663 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 664 %                                                                             %
 665 %                                                                             %
 666 %                                                                             %
 667 %     C l a m p I m a g e                                                     %
 668 %                                                                             %
 669 %                                                                             %
 670 %                                                                             %
 671 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 672 %
 673 %  ClampImage() set each pixel whose value is below zero to zero and any the
 674 %  pixel whose value is above the quantum range to the quantum range (e.g.
 675 %  65535) otherwise the pixel value remains unchanged.
 676 %
 677 %  The format of the ClampImage method is:
 678 %
 679 %      MagickBooleanType ClampImage(Image *image,ExceptionInfo *exception)
 680 %
 681 %  A description of each parameter follows:
 682 %
 683 %    o image: the image.
 684 %
 685 %    o exception: return any errors or warnings in this structure.
 686 %
 687 */
 688
 689 MagickExport MagickBooleanType ClampImage(Image *image,ExceptionInfo *exception)
 690 {
 691 #define ClampImageTag  "Clamp/Image"
 692
 693   CacheView
 694     *image_view;
 695
 696   MagickBooleanType
 697     status;
 698
 699   MagickOffsetType
 700     progress;
 701
 702   ssize_t
 703     y;
 704
 705   assert(image != (Image *) NULL);
 706   assert(image->signature == MagickCoreSignature);
 707   if (image->debug != MagickFalse)
 708     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 709   if (image->storage_class == PseudoClass)
 710     {
 711       register ssize_t
 712         i;
 713
 714       register PixelInfo
 715         *magick_restrict q;
 716
 717       q=image->colormap;
 718       for (i=0; i < (ssize_t) image->colors; i++)
 719       {
 720         q->red=(double) ClampPixel(q->red);
 721         q->green=(double) ClampPixel(q->green);
 722         q->blue=(double) ClampPixel(q->blue);
 723         q->alpha=(double) ClampPixel(q->alpha);
 724         q++;
 725       }
 726       return(SyncImage(image,exception));
 727     }
 728   /*
 729     Clamp image.
 730   */
 731   status=MagickTrue;
 732   progress=0;
 733   image_view=AcquireAuthenticCacheView(image,exception);
 734 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 735   #pragma omp parallel for schedule(static,4) shared(progress,status) \
 736     magick_threads(image,image,image->rows,1)
 737 #endif
 738   for (y=0; y < (ssize_t) image->rows; y++)
 739   {
 740     register ssize_t
 741       x;
 742
 743     register Quantum
 744       *magick_restrict q;
 745
 746     if (status == MagickFalse)
 747       continue;
 748     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
 749     if (q == (Quantum *) NULL)
 750       {
 751         status=MagickFalse;
 752         continue;
 753       }
 754     for (x=0; x < (ssize_t) image->columns; x++)
 755     {
 756       register ssize_t
 757         i;
 758
 759       if (GetPixelWriteMask(image,q) == 0)
 760         {
 761           q+=GetPixelChannels(image);
 762           continue;
 763         }
 764       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 765       {
 766         PixelChannel channel=GetPixelChannelChannel(image,i);
 767         PixelTrait traits=GetPixelChannelTraits(image,channel);
 768         if ((traits & UpdatePixelTrait) == 0)
 769           continue;
 770         q[i]=ClampPixel(q[i]);
 771       }
 772       q+=GetPixelChannels(image);
 773     }
 774     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
 775       status=MagickFalse;
 776     if (image->progress_monitor != (MagickProgressMonitor) NULL)
 777       {
 778         MagickBooleanType
 779           proceed;
 780
 781 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 782         #pragma omp critical (MagickCore_ClampImage)
 783 #endif
 784         proceed=SetImageProgress(image,ClampImageTag,progress++,image->rows);
 785         if (proceed == MagickFalse)
 786           status=MagickFalse;
 787       }
 788   }
 789   image_view=DestroyCacheView(image_view);
 790   return(status);
 791 }
 792 \f
 793 /*
 794 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 795 %                                                                             %
 796 %                                                                             %
 797 %                                                                             %
 798 %  D e s t r o y T h r e s h o l d M a p                                      %
 799 %                                                                             %
 800 %                                                                             %
 801 %                                                                             %
 802 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 803 %
 804 %  DestroyThresholdMap() de-allocate the given ThresholdMap
 805 %
 806 %  The format of the ListThresholdMaps method is:
 807 %
 808 %      ThresholdMap *DestroyThresholdMap(Threshold *map)
 809 %
 810 %  A description of each parameter follows.
 811 %
 812 %    o map:    Pointer to the Threshold map to destroy
 813 %
 814 */
 815 MagickExport ThresholdMap *DestroyThresholdMap(ThresholdMap *map)
 816 {
 817   assert(map != (ThresholdMap *) NULL);
 818   if (map->map_id != (char *) NULL)
 819     map->map_id=DestroyString(map->map_id);
 820   if (map->description != (char *) NULL)
 821     map->description=DestroyString(map->description);
 822   if (map->levels != (ssize_t *) NULL)
 823     map->levels=(ssize_t *) RelinquishMagickMemory(map->levels);
 824   map=(ThresholdMap *) RelinquishMagickMemory(map);
 825   return(map);
 826 }
 827 \f
 828 /*
 829 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 830 %                                                                             %
 831 %                                                                             %
 832 %                                                                             %
 833 %  G e t T h r e s h o l d M a p                                              %
 834 %                                                                             %
 835 %                                                                             %
 836 %                                                                             %
 837 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 838 %
 839 %  GetThresholdMap() loads and searches one or more threshold map files for the
 840 %  map matching the given name or alias.
 841 %
 842 %  The format of the GetThresholdMap method is:
 843 %
 844 %      ThresholdMap *GetThresholdMap(const char *map_id,
 845 %        ExceptionInfo *exception)
 846 %
 847 %  A description of each parameter follows.
 848 %
 849 %    o map_id:  ID of the map to look for.
 850 %
 851 %    o exception: return any errors or warnings in this structure.
 852 %
 853 */
 854 MagickExport ThresholdMap *GetThresholdMap(const char *map_id,
 855   ExceptionInfo *exception)
 856 {
 857   ThresholdMap
 858     *map;
 859
 860   map=GetThresholdMapFile(MinimalThresholdMap,"built-in",map_id,exception);
 861   if (map != (ThresholdMap *) NULL)
 862     return(map);
 863 #if !defined(MAGICKCORE_ZERO_CONFIGURATION_SUPPORT)
 864   {
 865     const StringInfo
 866       *option;
 867
 868     LinkedListInfo
 869       *options;
 870
 871     options=GetConfigureOptions(ThresholdsFilename,exception);
 872     option=(const StringInfo *) GetNextValueInLinkedList(options);
 873     while (option != (const StringInfo *) NULL)
 874     {
 875       map=GetThresholdMapFile((const char *) GetStringInfoDatum(option),
 876         GetStringInfoPath(option),map_id,exception);
 877       if (map != (ThresholdMap *) NULL)
 878         break;
 879       option=(const StringInfo *) GetNextValueInLinkedList(options);
 880     }
 881     options=DestroyConfigureOptions(options);
 882   }
 883 #endif
 884   return(map);
 885 }
 886 \f
 887 /*
 888 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 889 %                                                                             %
 890 %                                                                             %
 891 %                                                                             %
 892 +  G e t T h r e s h o l d M a p F i l e                                      %
 893 %                                                                             %
 894 %                                                                             %
 895 %                                                                             %
 896 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 897 %
 898 %  GetThresholdMapFile() look for a given threshold map name or alias in the
 899 %  given XML file data, and return the allocated the map when found.
 900 %
 901 %  The format of the ListThresholdMaps method is:
 902 %
 903 %      ThresholdMap *GetThresholdMap(const char *xml,const char *filename,
 904 %         const char *map_id,ExceptionInfo *exception)
 905 %
 906 %  A description of each parameter follows.
 907 %
 908 %    o xml:  The threshold map list in XML format.
 909 %
 910 %    o filename:  The threshold map XML filename.
 911 %
 912 %    o map_id:  ID of the map to look for in XML list.
 913 %
 914 %    o exception: return any errors or warnings in this structure.
 915 %
 916 */
 917 static ThresholdMap *GetThresholdMapFile(const char *xml,const char *filename,
 918   const char *map_id,ExceptionInfo *exception)
 919 {
 920   char
 921     *p;
 922
 923   const char
 924     *attribute,
 925     *content;
 926
 927   double
 928     value;
 929
 930   register ssize_t
 931     i;
 932
 933   ThresholdMap
 934     *map;
 935
 936   XMLTreeInfo
 937     *description,
 938     *levels,
 939     *threshold,
 940     *thresholds;
 941
 942   (void) LogMagickEvent(ConfigureEvent,GetMagickModule(),
 943     "Loading threshold map file \"%s\" ...",filename);
 944   map=(ThresholdMap *) NULL;
 945   thresholds=NewXMLTree(xml,exception);
 946   if (thresholds == (XMLTreeInfo *) NULL)
 947     return(map);
 948   for (threshold=GetXMLTreeChild(thresholds,"threshold");
 949        threshold != (XMLTreeInfo *) NULL;
 950        threshold=GetNextXMLTreeTag(threshold))
 951   {
 952     attribute=GetXMLTreeAttribute(threshold,"map");
 953     if ((attribute != (char *) NULL) && (LocaleCompare(map_id,attribute) == 0))
 954       break;
 955     attribute=GetXMLTreeAttribute(threshold,"alias");
 956     if ((attribute != (char *) NULL) && (LocaleCompare(map_id,attribute) == 0))
 957       break;
 958   }
 959   if (threshold == (XMLTreeInfo *) NULL)
 960     {
 961       thresholds=DestroyXMLTree(thresholds);
 962       return(map);
 963     }
 964   description=GetXMLTreeChild(threshold,"description");
 965   if (description == (XMLTreeInfo *) NULL)
 966     {
 967       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 968         "XmlMissingElement", "<description>, map \"%s\"",map_id);
 969       thresholds=DestroyXMLTree(thresholds);
 970       return(map);
 971     }
 972   levels=GetXMLTreeChild(threshold,"levels");
 973   if (levels == (XMLTreeInfo *) NULL)
 974     {
 975       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 976         "XmlMissingElement", "<levels>, map \"%s\"", map_id);
 977       thresholds=DestroyXMLTree(thresholds);
 978       return(map);
 979     }
 980   map=(ThresholdMap *) AcquireMagickMemory(sizeof(ThresholdMap));
 981   if (map == (ThresholdMap *) NULL)
 982     ThrowFatalException(ResourceLimitFatalError,"UnableToAcquireThresholdMap");
 983   map->map_id=(char *) NULL;
 984   map->description=(char *) NULL;
 985   map->levels=(ssize_t *) NULL;
 986   attribute=GetXMLTreeAttribute(threshold,"map");
 987   if (attribute != (char *) NULL)
 988     map->map_id=ConstantString(attribute);
 989   content=GetXMLTreeContent(description);
 990   if (content != (char *) NULL)
 991     map->description=ConstantString(content);
 992   attribute=GetXMLTreeAttribute(levels,"width");
 993   if (attribute == (char *) NULL)
 994     {
 995       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 996         "XmlMissingAttribute", "<levels width>, map \"%s\"",map_id);
 997       thresholds=DestroyXMLTree(thresholds);
 998       map=DestroyThresholdMap(map);
 999       return(map);
1000     }
1001   map->width=StringToUnsignedLong(attribute);
1002   if (map->width == 0)
1003     {
1004       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1005        "XmlInvalidAttribute", "<levels width>, map \"%s\"",map_id);
1006       thresholds=DestroyXMLTree(thresholds);
1007       map=DestroyThresholdMap(map);
1008       return(map);
1009     }
1010   attribute=GetXMLTreeAttribute(levels,"height");
1011   if (attribute == (char *) NULL)
1012     {
1013       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1014         "XmlMissingAttribute", "<levels height>, map \"%s\"",map_id);
1015       thresholds=DestroyXMLTree(thresholds);
1016       map=DestroyThresholdMap(map);
1017       return(map);
1018     }
1019   map->height=StringToUnsignedLong(attribute);
1020   if (map->height == 0)
1021     {
1022       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1023         "XmlInvalidAttribute", "<levels height>, map \"%s\"",map_id);
1024       thresholds=DestroyXMLTree(thresholds);
1025       map=DestroyThresholdMap(map);
1026       return(map);
1027     }
1028   attribute=GetXMLTreeAttribute(levels,"divisor");
1029   if (attribute == (char *) NULL)
1030     {
1031       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1032         "XmlMissingAttribute", "<levels divisor>, map \"%s\"",map_id);
1033       thresholds=DestroyXMLTree(thresholds);
1034       map=DestroyThresholdMap(map);
1035       return(map);
1036     }
1037   map->divisor=(ssize_t) StringToLong(attribute);
1038   if (map->divisor < 2)
1039     {
1040       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1041         "XmlInvalidAttribute", "<levels divisor>, map \"%s\"",map_id);
1042       thresholds=DestroyXMLTree(thresholds);
1043       map=DestroyThresholdMap(map);
1044       return(map);
1045     }
1046   content=GetXMLTreeContent(levels);
1047   if (content == (char *) NULL)
1048     {
1049       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1050         "XmlMissingContent", "<levels>, map \"%s\"",map_id);
1051       thresholds=DestroyXMLTree(thresholds);
1052       map=DestroyThresholdMap(map);
1053       return(map);
1054     }
1055   map->levels=(ssize_t *) AcquireQuantumMemory((size_t) map->width,map->height*
1056     sizeof(*map->levels));
1057   if (map->levels == (ssize_t *) NULL)
1058     ThrowFatalException(ResourceLimitFatalError,"UnableToAcquireThresholdMap");
1059   for (i=0; i < (ssize_t) (map->width*map->height); i++)
1060   {
1061     map->levels[i]=(ssize_t) strtol(content,&p,10);
1062     if (p == content)
1063       {
1064         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1065           "XmlInvalidContent", "<level> too few values, map \"%s\"",map_id);
1066         thresholds=DestroyXMLTree(thresholds);
1067         map=DestroyThresholdMap(map);
1068         return(map);
1069       }
1070     if ((map->levels[i] < 0) || (map->levels[i] > map->divisor))
1071       {
1072         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1073           "XmlInvalidContent", "<level> %.20g out of range, map \"%s\"",
1074           (double) map->levels[i],map_id);
1075         thresholds=DestroyXMLTree(thresholds);
1076         map=DestroyThresholdMap(map);
1077         return(map);
1078       }
1079     content=p;
1080   }
1081   value=(double) strtol(content,&p,10);
1082   (void) value;
1083   if (p != content)
1084     {
1085       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1086         "XmlInvalidContent", "<level> too many values, map \"%s\"",map_id);
1087      thresholds=DestroyXMLTree(thresholds);
1088      map=DestroyThresholdMap(map);
1089      return(map);
1090    }
1091   thresholds=DestroyXMLTree(thresholds);
1092   return(map);
1093 }
1094 \f
1095 /*
1096 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1097 %                                                                             %
1098 %                                                                             %
1099 %                                                                             %
1100 +  L i s t T h r e s h o l d M a p F i l e                                    %
1101 %                                                                             %
1102 %                                                                             %
1103 %                                                                             %
1104 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1105 %
1106 %  ListThresholdMapFile() lists the threshold maps and their descriptions
1107 %  in the given XML file data.
1108 %
1109 %  The format of the ListThresholdMaps method is:
1110 %
1111 %      MagickBooleanType ListThresholdMaps(FILE *file,const char*xml,
1112 %         const char *filename,ExceptionInfo *exception)
1113 %
1114 %  A description of each parameter follows.
1115 %
1116 %    o file:  An pointer to the output FILE.
1117 %
1118 %    o xml:  The threshold map list in XML format.
1119 %
1120 %    o filename:  The threshold map XML filename.
1121 %
1122 %    o exception: return any errors or warnings in this structure.
1123 %
1124 */
1125 MagickBooleanType ListThresholdMapFile(FILE *file,const char *xml,
1126   const char *filename,ExceptionInfo *exception)
1127 {
1128   const char
1129     *alias,
1130     *content,
1131     *map;
1132
1133   XMLTreeInfo
1134     *description,
1135     *threshold,
1136     *thresholds;
1137
1138   assert( xml != (char *) NULL );
1139   assert( file != (FILE *) NULL );
1140   (void) LogMagickEvent(ConfigureEvent,GetMagickModule(),
1141     "Loading threshold map file \"%s\" ...",filename);
1142   thresholds=NewXMLTree(xml,exception);
1143   if ( thresholds == (XMLTreeInfo *) NULL )
1144     return(MagickFalse);
1145   (void) FormatLocaleFile(file,"%-16s %-12s %s\n","Map","Alias","Description");
1146   (void) FormatLocaleFile(file,
1147     "----------------------------------------------------\n");
1148   threshold=GetXMLTreeChild(thresholds,"threshold");
1149   for ( ; threshold != (XMLTreeInfo *) NULL;
1150           threshold=GetNextXMLTreeTag(threshold))
1151   {
1152     map=GetXMLTreeAttribute(threshold,"map");
1153     if (map == (char *) NULL)
1154       {
1155         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1156           "XmlMissingAttribute", "<map>");
1157         thresholds=DestroyXMLTree(thresholds);
1158         return(MagickFalse);
1159       }
1160     alias=GetXMLTreeAttribute(threshold,"alias");
1161     description=GetXMLTreeChild(threshold,"description");
1162     if (description == (XMLTreeInfo *) NULL)
1163       {
1164         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1165           "XmlMissingElement", "<description>, map \"%s\"",map);
1166         thresholds=DestroyXMLTree(thresholds);
1167         return(MagickFalse);
1168       }
1169     content=GetXMLTreeContent(description);
1170     if (content == (char *) NULL)
1171       {
1172         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1173           "XmlMissingContent", "<description>, map \"%s\"", map);
1174         thresholds=DestroyXMLTree(thresholds);
1175         return(MagickFalse);
1176       }
1177     (void) FormatLocaleFile(file,"%-16s %-12s %s\n",map,alias ? alias : "",
1178       content);
1179   }
1180   thresholds=DestroyXMLTree(thresholds);
1181   return(MagickTrue);
1182 }
1183 \f
1184 /*
1185 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1186 %                                                                             %
1187 %                                                                             %
1188 %                                                                             %
1189 %  L i s t T h r e s h o l d M a p s                                          %
1190 %                                                                             %
1191 %                                                                             %
1192 %                                                                             %
1193 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1194 %
1195 %  ListThresholdMaps() lists the threshold maps and their descriptions
1196 %  as defined by "threshold.xml" to a file.
1197 %
1198 %  The format of the ListThresholdMaps method is:
1199 %
1200 %      MagickBooleanType ListThresholdMaps(FILE *file,ExceptionInfo *exception)
1201 %
1202 %  A description of each parameter follows.
1203 %
1204 %    o file:  An pointer to the output FILE.
1205 %
1206 %    o exception: return any errors or warnings in this structure.
1207 %
1208 */
1209 MagickExport MagickBooleanType ListThresholdMaps(FILE *file,
1210   ExceptionInfo *exception)
1211 {
1212   const StringInfo
1213     *option;
1214
1215   LinkedListInfo
1216     *options;
1217
1218   MagickStatusType
1219     status;
1220
1221   status=MagickTrue;
1222   if (file == (FILE *) NULL)
1223     file=stdout;
1224   options=GetConfigureOptions(ThresholdsFilename,exception);
1225   (void) FormatLocaleFile(file,
1226     "\n   Threshold Maps for Ordered Dither Operations\n");
1227   option=(const StringInfo *) GetNextValueInLinkedList(options);
1228   while (option != (const StringInfo *) NULL)
1229   {
1230     (void) FormatLocaleFile(file,"\nPath: %s\n\n",GetStringInfoPath(option));
1231     status&=ListThresholdMapFile(file,(const char *) GetStringInfoDatum(option),
1232       GetStringInfoPath(option),exception);
1233     option=(const StringInfo *) GetNextValueInLinkedList(options);
1234   }
1235   options=DestroyConfigureOptions(options);
1236   return(status != 0 ? MagickTrue : MagickFalse);
1237 }
1238 \f
1239 /*
1240 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1241 %                                                                             %
1242 %                                                                             %
1243 %                                                                             %
1244 %     O r d e r e d D i t h e r I m a g e                                     %
1245 %                                                                             %
1246 %                                                                             %
1247 %                                                                             %
1248 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1249 %
1250 %  OrderedDitherImage() will perform a ordered dither based on a number
1251 %  of pre-defined dithering threshold maps, but over multiple intensity
1252 %  levels, which can be different for different channels, according to the
1253 %  input argument.
1254 %
1255 %  The format of the OrderedDitherImage method is:
1256 %
1257 %      MagickBooleanType OrderedDitherImage(Image *image,
1258 %        const char *threshold_map,ExceptionInfo *exception)
1259 %
1260 %  A description of each parameter follows:
1261 %
1262 %    o image: the image.
1263 %
1264 %    o threshold_map: A string containing the name of the threshold dither
1265 %      map to use, followed by zero or more numbers representing the number
1266 %      of color levels tho dither between.
1267 %
1268 %      Any level number less than 2 will be equivalent to 2, and means only
1269 %      binary dithering will be applied to each color channel.
1270 %
1271 %      No numbers also means a 2 level (bitmap) dither will be applied to all
1272 %      channels, while a single number is the number of levels applied to each
1273 %      channel in sequence.  More numbers will be applied in turn to each of
1274 %      the color channels.
1275 %
1276 %      For example: "o3x3,6" will generate a 6 level posterization of the
1277 %      image with a ordered 3x3 diffused pixel dither being applied between
1278 %      each level. While checker,8,8,4 will produce a 332 colormaped image
1279 %      with only a single checkerboard hash pattern (50% grey) between each
1280 %      color level, to basically double the number of color levels with
1281 %      a bare minimim of dithering.
1282 %
1283 %    o exception: return any errors or warnings in this structure.
1284 %
1285 */
1286 MagickExport MagickBooleanType OrderedDitherImage(Image *image,
1287   const char *threshold_map,ExceptionInfo *exception)
1288 {
1289 #define DitherImageTag  "Dither/Image"
1290
1291   CacheView
1292     *image_view;
1293
1294   char
1295     token[MagickPathExtent];
1296
1297   const char
1298     *p;
1299
1300   double
1301     levels[CompositePixelChannel];
1302
1303   MagickBooleanType
1304     status;
1305
1306   MagickOffsetType
1307     progress;
1308
1309   register ssize_t
1310     i;
1311
1312   ssize_t
1313     y;
1314
1315   ThresholdMap
1316     *map;
1317
1318   assert(image != (Image *) NULL);
1319   assert(image->signature == MagickCoreSignature);
1320   if (image->debug != MagickFalse)
1321     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1322   assert(exception != (ExceptionInfo *) NULL);
1323   assert(exception->signature == MagickCoreSignature);
1324   if (threshold_map == (const char *) NULL)
1325     return(MagickTrue);
1326   p=(char *) threshold_map;
1327   while (((isspace((int) ((unsigned char) *p)) != 0) || (*p == ',')) &&
1328          (*p != '\0'))
1329     p++;
1330   threshold_map=p;
1331   while (((isspace((int) ((unsigned char) *p)) == 0) && (*p != ',')) &&
1332          (*p != '\0'))
1333   {
1334     if ((p-threshold_map) >= (MagickPathExtent-1))
1335       break;
1336     token[p-threshold_map]=(*p);
1337     p++;
1338   }
1339   token[p-threshold_map]='\0';
1340   map=GetThresholdMap(token,exception);
1341   if (map == (ThresholdMap *) NULL)
1342     {
1343       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1344         "InvalidArgument","%s : '%s'","ordered-dither",threshold_map);
1345       return(MagickFalse);
1346     }
1347   for (i=0; i < MaxPixelChannels; i++)
1348     levels[i]=2.0;
1349   p=strchr((char *) threshold_map,',');
1350   if ((p != (char *) NULL) && (isdigit((int) ((unsigned char) *(++p))) != 0))
1351     {
1352       GetNextToken(p,&p,MagickPathExtent,token);
1353       for (i=0; (i < MaxPixelChannels); i++)
1354         levels[i]=StringToDouble(token,(char **) NULL);
1355       for (i=0; (*p != '\0') && (i < MaxPixelChannels); i++)
1356       {
1357         GetNextToken(p,&p,MagickPathExtent,token);
1358         if (*token == ',')
1359           GetNextToken(p,&p,MagickPathExtent,token);
1360         levels[i]=StringToDouble(token,(char **) NULL);
1361       }
1362     }
1363   for (i=0; i < MaxPixelChannels; i++)
1364     if (fabs(levels[i]) >= 1)
1365       levels[i]-=1.0;
1366   if (SetImageStorageClass(image,DirectClass,exception) == MagickFalse)
1367     return(MagickFalse);
1368   status=MagickTrue;
1369   progress=0;
1370   image_view=AcquireAuthenticCacheView(image,exception);
1371 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1372   #pragma omp parallel for schedule(static,4) shared(progress,status) \
1373     magick_threads(image,image,image->rows,1)
1374 #endif
1375   for (y=0; y < (ssize_t) image->rows; y++)
1376   {
1377     register ssize_t
1378       x;
1379
1380     register Quantum
1381       *magick_restrict q;
1382
1383     if (status == MagickFalse)
1384       continue;
1385     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1386     if (q == (Quantum *) NULL)
1387       {
1388         status=MagickFalse;
1389         continue;
1390       }
1391     for (x=0; x < (ssize_t) image->columns; x++)
1392     {
1393       register ssize_t
1394         i;
1395
1396       ssize_t
1397         n;
1398
1399       n=0;
1400       if (GetPixelWriteMask(image,q) == 0)
1401         {
1402           q+=GetPixelChannels(image);
1403           continue;
1404         }
1405       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1406       {
1407         ssize_t
1408           level,
1409           threshold;
1410
1411         PixelChannel channel=GetPixelChannelChannel(image,i);
1412         PixelTrait traits=GetPixelChannelTraits(image,channel);
1413         if ((traits & UpdatePixelTrait) == 0)
1414           continue;
1415         if (fabs(levels[n]) < MagickEpsilon)
1416           {
1417             n++;
1418             continue;
1419           }
1420         threshold=(ssize_t) (QuantumScale*q[i]*(levels[n]*(map->divisor-1)+1));
1421         level=threshold/(map->divisor-1);
1422         threshold-=level*(map->divisor-1);
1423         q[i]=ClampToQuantum((double) (level+(threshold >=
1424           map->levels[(x % map->width)+map->width*(y % map->height)]))*
1425           QuantumRange/levels[n]);
1426         n++;
1427       }
1428       q+=GetPixelChannels(image);
1429     }
1430     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1431       status=MagickFalse;
1432     if (image->progress_monitor != (MagickProgressMonitor) NULL)
1433       {
1434         MagickBooleanType
1435           proceed;
1436
1437 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1438         #pragma omp critical (MagickCore_OrderedDitherImage)
1439 #endif
1440         proceed=SetImageProgress(image,DitherImageTag,progress++,image->rows);
1441         if (proceed == MagickFalse)
1442           status=MagickFalse;
1443       }
1444   }
1445   image_view=DestroyCacheView(image_view);
1446   map=DestroyThresholdMap(map);
1447   return(MagickTrue);
1448 }
1449 \f
1450 /*
1451 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1452 %                                                                             %
1453 %                                                                             %
1454 %                                                                             %
1455 %     P e r c e p t i b l e I m a g e                                         %
1456 %                                                                             %
1457 %                                                                             %
1458 %                                                                             %
1459 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1460 %
1461 %  PerceptibleImage() set each pixel whose value is less than |epsilon| to
1462 %  epsilon or -epsilon (whichever is closer) otherwise the pixel value remains
1463 %  unchanged.
1464 %
1465 %  The format of the PerceptibleImage method is:
1466 %
1467 %      MagickBooleanType PerceptibleImage(Image *image,const double epsilon,
1468 %        ExceptionInfo *exception)
1469 %
1470 %  A description of each parameter follows:
1471 %
1472 %    o image: the image.
1473 %
1474 %    o epsilon: the epsilon threshold (e.g. 1.0e-9).
1475 %
1476 %    o exception: return any errors or warnings in this structure.
1477 %
1478 */
1479
1480 static inline Quantum PerceptibleThreshold(const Quantum quantum,
1481   const double epsilon)
1482 {
1483   double
1484     sign;
1485
1486   sign=(double) quantum < 0.0 ? -1.0 : 1.0;
1487   if ((sign*quantum) >= epsilon)
1488     return(quantum);
1489   return((Quantum) (sign*epsilon));
1490 }
1491
1492 MagickExport MagickBooleanType PerceptibleImage(Image *image,
1493   const double epsilon,ExceptionInfo *exception)
1494 {
1495 #define PerceptibleImageTag  "Perceptible/Image"
1496
1497   CacheView
1498     *image_view;
1499
1500   MagickBooleanType
1501     status;
1502
1503   MagickOffsetType
1504     progress;
1505
1506   ssize_t
1507     y;
1508
1509   assert(image != (Image *) NULL);
1510   assert(image->signature == MagickCoreSignature);
1511   if (image->debug != MagickFalse)
1512     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1513   if (image->storage_class == PseudoClass)
1514     {
1515       register ssize_t
1516         i;
1517
1518       register PixelInfo
1519         *magick_restrict q;
1520
1521       q=image->colormap;
1522       for (i=0; i < (ssize_t) image->colors; i++)
1523       {
1524         q->red=(double) PerceptibleThreshold(ClampToQuantum(q->red),
1525           epsilon);
1526         q->green=(double) PerceptibleThreshold(ClampToQuantum(q->green),
1527           epsilon);
1528         q->blue=(double) PerceptibleThreshold(ClampToQuantum(q->blue),
1529           epsilon);
1530         q->alpha=(double) PerceptibleThreshold(ClampToQuantum(q->alpha),
1531           epsilon);
1532         q++;
1533       }
1534       return(SyncImage(image,exception));
1535     }
1536   /*
1537     Perceptible image.
1538   */
1539   status=MagickTrue;
1540   progress=0;
1541   image_view=AcquireAuthenticCacheView(image,exception);
1542 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1543   #pragma omp parallel for schedule(static,4) shared(progress,status) \
1544     magick_threads(image,image,image->rows,1)
1545 #endif
1546   for (y=0; y < (ssize_t) image->rows; y++)
1547   {
1548     register ssize_t
1549       x;
1550
1551     register Quantum
1552       *magick_restrict q;
1553
1554     if (status == MagickFalse)
1555       continue;
1556     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1557     if (q == (Quantum *) NULL)
1558       {
1559         status=MagickFalse;
1560         continue;
1561       }
1562     for (x=0; x < (ssize_t) image->columns; x++)
1563     {
1564       register ssize_t
1565         i;
1566
1567       if (GetPixelWriteMask(image,q) == 0)
1568         {
1569           q+=GetPixelChannels(image);
1570           continue;
1571         }
1572       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1573       {
1574         PixelChannel channel=GetPixelChannelChannel(image,i);
1575         PixelTrait traits=GetPixelChannelTraits(image,channel);
1576         if (traits == UndefinedPixelTrait)
1577           continue;
1578         q[i]=PerceptibleThreshold(q[i],epsilon);
1579       }
1580       q+=GetPixelChannels(image);
1581     }
1582     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1583       status=MagickFalse;
1584     if (image->progress_monitor != (MagickProgressMonitor) NULL)
1585       {
1586         MagickBooleanType
1587           proceed;
1588
1589 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1590         #pragma omp critical (MagickCore_PerceptibleImage)
1591 #endif
1592         proceed=SetImageProgress(image,PerceptibleImageTag,progress++,image->rows);
1593         if (proceed == MagickFalse)
1594           status=MagickFalse;
1595       }
1596   }
1597   image_view=DestroyCacheView(image_view);
1598   return(status);
1599 }
1600 \f
1601 /*
1602 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1603 %                                                                             %
1604 %                                                                             %
1605 %                                                                             %
1606 %     R a n d o m T h r e s h o l d I m a g e                                 %
1607 %                                                                             %
1608 %                                                                             %
1609 %                                                                             %
1610 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1611 %
1612 %  RandomThresholdImage() changes the value of individual pixels based on the
1613 %  intensity of each pixel compared to a random threshold.  The result is a
1614 %  low-contrast, two color image.
1615 %
1616 %  The format of the RandomThresholdImage method is:
1617 %
1618 %      MagickBooleanType RandomThresholdImage(Image *image,
1619 %        const char *thresholds,ExceptionInfo *exception)
1620 %
1621 %  A description of each parameter follows:
1622 %
1623 %    o image: the image.
1624 %
1625 %    o low,high: Specify the high and low thresholds. These values range from
1626 %      0 to QuantumRange.
1627 %
1628 %    o exception: return any errors or warnings in this structure.
1629 %
1630 */
1631 MagickExport MagickBooleanType RandomThresholdImage(Image *image,
1632   const double min_threshold, const double max_threshold,ExceptionInfo *exception)
1633 {
1634 #define ThresholdImageTag  "Threshold/Image"
1635
1636   CacheView
1637     *image_view;
1638
1639   MagickBooleanType
1640     status;
1641
1642   MagickOffsetType
1643     progress;
1644
1645   PixelInfo
1646     threshold;
1647
1648   RandomInfo
1649     **magick_restrict random_info;
1650
1651   ssize_t
1652     y;
1653
1654 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1655   unsigned long
1656     key;
1657 #endif
1658
1659   assert(image != (Image *) NULL);
1660   assert(image->signature == MagickCoreSignature);
1661   if (image->debug != MagickFalse)
1662     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1663   assert(exception != (ExceptionInfo *) NULL);
1664   assert(exception->signature == MagickCoreSignature);
1665   if (SetImageStorageClass(image,DirectClass,exception) == MagickFalse)
1666     return(MagickFalse);
1667   GetPixelInfo(image,&threshold);
1668   /*
1669     Random threshold image.
1670   */
1671   status=MagickTrue;
1672   progress=0;
1673   random_info=AcquireRandomInfoThreadSet();
1674   image_view=AcquireAuthenticCacheView(image,exception);
1675 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1676   key=GetRandomSecretKey(random_info[0]);
1677   #pragma omp parallel for schedule(static,4) shared(progress,status) \
1678     magick_threads(image,image,image->rows,key == ~0UL)
1679 #endif
1680   for (y=0; y < (ssize_t) image->rows; y++)
1681   {
1682     const int
1683       id = GetOpenMPThreadId();
1684
1685     register Quantum
1686       *magick_restrict q;
1687
1688     register ssize_t
1689       x;
1690
1691     if (status == MagickFalse)
1692       continue;
1693     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1694     if (q == (Quantum *) NULL)
1695       {
1696         status=MagickFalse;
1697         continue;
1698       }
1699     for (x=0; x < (ssize_t) image->columns; x++)
1700     {
1701       register ssize_t
1702         i;
1703
1704       if (GetPixelWriteMask(image,q) == 0)
1705         {
1706           q+=GetPixelChannels(image);
1707           continue;
1708         }
1709       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1710       {
1711         double
1712           threshold;
1713
1714         PixelChannel channel=GetPixelChannelChannel(image,i);
1715         PixelTrait traits=GetPixelChannelTraits(image,channel);
1716         if ((traits & UpdatePixelTrait) == 0)
1717           continue;
1718         if ((double) q[i] < min_threshold)
1719           threshold=min_threshold;
1720         else
1721           if ((double) q[i] > max_threshold)
1722             threshold=max_threshold;
1723           else
1724             threshold=(double) (QuantumRange*
1725               GetPseudoRandomValue(random_info[id]));
1726         q[i]=(double) q[i] <= threshold ? 0 : QuantumRange;
1727       }
1728       q+=GetPixelChannels(image);
1729     }
1730     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1731       status=MagickFalse;
1732     if (image->progress_monitor != (MagickProgressMonitor) NULL)
1733       {
1734         MagickBooleanType
1735           proceed;
1736
1737 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1738         #pragma omp critical (MagickCore_RandomThresholdImage)
1739 #endif
1740         proceed=SetImageProgress(image,ThresholdImageTag,progress++,
1741           image->rows);
1742         if (proceed == MagickFalse)
1743           status=MagickFalse;
1744       }
1745   }
1746   image_view=DestroyCacheView(image_view);
1747   random_info=DestroyRandomInfoThreadSet(random_info);
1748   return(status);
1749 }
1750 \f
1751 /*
1752 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1753 %                                                                             %
1754 %                                                                             %
1755 %                                                                             %
1756 %     W h i t e T h r e s h o l d I m a g e                                   %
1757 %                                                                             %
1758 %                                                                             %
1759 %                                                                             %
1760 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1761 %
1762 %  WhiteThresholdImage() is like ThresholdImage() but forces all pixels above
1763 %  the threshold into white while leaving all pixels at or below the threshold
1764 %  unchanged.
1765 %
1766 %  The format of the WhiteThresholdImage method is:
1767 %
1768 %      MagickBooleanType WhiteThresholdImage(Image *image,
1769 %        const char *threshold,ExceptionInfo *exception)
1770 %
1771 %  A description of each parameter follows:
1772 %
1773 %    o image: the image.
1774 %
1775 %    o threshold: Define the threshold value.
1776 %
1777 %    o exception: return any errors or warnings in this structure.
1778 %
1779 */
1780 MagickExport MagickBooleanType WhiteThresholdImage(Image *image,
1781   const char *thresholds,ExceptionInfo *exception)
1782 {
1783 #define ThresholdImageTag  "Threshold/Image"
1784
1785   CacheView
1786     *image_view;
1787
1788   GeometryInfo
1789     geometry_info;
1790
1791   MagickBooleanType
1792     status;
1793
1794   MagickOffsetType
1795     progress;
1796
1797   PixelInfo
1798     threshold;
1799
1800   MagickStatusType
1801     flags;
1802
1803   ssize_t
1804     y;
1805
1806   assert(image != (Image *) NULL);
1807   assert(image->signature == MagickCoreSignature);
1808   if (image->debug != MagickFalse)
1809     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1810   if (thresholds == (const char *) NULL)
1811     return(MagickTrue);
1812   if (SetImageStorageClass(image,DirectClass,exception) == MagickFalse)
1813     return(MagickFalse);
1814   if (IsGrayColorspace(image->colorspace) != MagickFalse)
1815     (void) TransformImageColorspace(image,sRGBColorspace,exception);
1816   GetPixelInfo(image,&threshold);
1817   flags=ParseGeometry(thresholds,&geometry_info);
1818   threshold.red=geometry_info.rho;
1819   threshold.green=geometry_info.rho;
1820   threshold.blue=geometry_info.rho;
1821   threshold.black=geometry_info.rho;
1822   threshold.alpha=100.0;
1823   if ((flags & SigmaValue) != 0)
1824     threshold.green=geometry_info.sigma;
1825   if ((flags & XiValue) != 0)
1826     threshold.blue=geometry_info.xi;
1827   if ((flags & PsiValue) != 0)
1828     threshold.alpha=geometry_info.psi;
1829   if (threshold.colorspace == CMYKColorspace)
1830     {
1831       if ((flags & PsiValue) != 0)
1832         threshold.black=geometry_info.psi;
1833       if ((flags & ChiValue) != 0)
1834         threshold.alpha=geometry_info.chi;
1835     }
1836   if ((flags & PercentValue) != 0)
1837     {
1838       threshold.red*=(MagickRealType) (QuantumRange/100.0);
1839       threshold.green*=(MagickRealType) (QuantumRange/100.0);
1840       threshold.blue*=(MagickRealType) (QuantumRange/100.0);
1841       threshold.black*=(MagickRealType) (QuantumRange/100.0);
1842       threshold.alpha*=(MagickRealType) (QuantumRange/100.0);
1843     }
1844   /*
1845     White threshold image.
1846   */
1847   status=MagickTrue;
1848   progress=0;
1849   image_view=AcquireAuthenticCacheView(image,exception);
1850 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1851   #pragma omp parallel for schedule(static,4) shared(progress,status) \
1852     magick_threads(image,image,image->rows,1)
1853 #endif
1854   for (y=0; y < (ssize_t) image->rows; y++)
1855   {
1856     register ssize_t
1857       x;
1858
1859     register Quantum
1860       *magick_restrict q;
1861
1862     if (status == MagickFalse)
1863       continue;
1864     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1865     if (q == (Quantum *) NULL)
1866       {
1867         status=MagickFalse;
1868         continue;
1869       }
1870     for (x=0; x < (ssize_t) image->columns; x++)
1871     {
1872       double
1873         pixel;
1874
1875       register ssize_t
1876         i;
1877
1878       if (GetPixelWriteMask(image,q) == 0)
1879         {
1880           q+=GetPixelChannels(image);
1881           continue;
1882         }
1883       pixel=GetPixelIntensity(image,q);
1884       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1885       {
1886         PixelChannel channel=GetPixelChannelChannel(image,i);
1887         PixelTrait traits=GetPixelChannelTraits(image,channel);
1888         if ((traits & UpdatePixelTrait) == 0)
1889           continue;
1890         if (image->channel_mask != DefaultChannels)
1891           pixel=(double) q[i];
1892         if (pixel > GetPixelInfoChannel(&threshold,channel))
1893           q[i]=QuantumRange;
1894       }
1895       q+=GetPixelChannels(image);
1896     }
1897     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1898       status=MagickFalse;
1899     if (image->progress_monitor != (MagickProgressMonitor) NULL)
1900       {
1901         MagickBooleanType
1902           proceed;
1903
1904 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1905         #pragma omp critical (MagickCore_WhiteThresholdImage)
1906 #endif
1907         proceed=SetImageProgress(image,ThresholdImageTag,progress++,
1908           image->rows);
1909         if (proceed == MagickFalse)
1910           status=MagickFalse;
1911       }
1912   }
1913   image_view=DestroyCacheView(image_view);
1914   return(status);
1915 }