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 %                                 John Cristy                                 %
  17 %                                 October 1996                                %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2012 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/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/quantize.h"
  73 #include "MagickCore/quantum.h"
  74 #include "MagickCore/random_.h"
  75 #include "MagickCore/random-private.h"
  76 #include "MagickCore/resize.h"
  77 #include "MagickCore/resource_.h"
  78 #include "MagickCore/segment.h"
  79 #include "MagickCore/shear.h"
  80 #include "MagickCore/signature-private.h"
  81 #include "MagickCore/string_.h"
  82 #include "MagickCore/string-private.h"
  83 #include "MagickCore/thread-private.h"
  84 #include "MagickCore/threshold.h"
  85 #include "MagickCore/token.h"
  86 #include "MagickCore/transform.h"
  87 #include "MagickCore/xml-tree.h"
  88 #include "MagickCore/xml-tree-private.h"
  89 \f
  90 /*
  91   Define declarations.
  92 */
  93 #define ThresholdsFilename  "thresholds.xml"
  94 \f
  95 /*
  96   Typedef declarations.
  97 */
  98 struct _ThresholdMap
  99 {
 100   char
 101     *map_id,
 102     *description;
 103
 104   size_t
 105     width,
 106     height;
 107
 108   ssize_t
 109     divisor,
 110     *levels;
 111 };
 112 \f
 113 /*
 114   Forward declarations.
 115 */
 116 static ThresholdMap
 117   *GetThresholdMapFile(const char *,const char *,const char *,ExceptionInfo *);
 118 \f
 119 /*
 120 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 121 %                                                                             %
 122 %                                                                             %
 123 %                                                                             %
 124 %     A d a p t i v e T h r e s h o l d I m a g e                             %
 125 %                                                                             %
 126 %                                                                             %
 127 %                                                                             %
 128 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 129 %
 130 %  AdaptiveThresholdImage() selects an individual threshold for each pixel
 131 %  based on the range of intensity values in its local neighborhood.  This
 132 %  allows for thresholding of an image whose global intensity histogram
 133 %  doesn't contain distinctive peaks.
 134 %
 135 %  The format of the AdaptiveThresholdImage method is:
 136 %
 137 %      Image *AdaptiveThresholdImage(const Image *image,const size_t width,
 138 %        const size_t height,const double bias,ExceptionInfo *exception)
 139 %
 140 %  A description of each parameter follows:
 141 %
 142 %    o image: the image.
 143 %
 144 %    o width: the width of the local neighborhood.
 145 %
 146 %    o height: the height of the local neighborhood.
 147 %
 148 %    o bias: the mean bias.
 149 %
 150 %    o exception: return any errors or warnings in this structure.
 151 %
 152 */
 153 MagickExport Image *AdaptiveThresholdImage(const Image *image,
 154   const size_t width,const size_t height,const double bias,
 155   ExceptionInfo *exception)
 156 {
 157 #define AdaptiveThresholdImageTag  "AdaptiveThreshold/Image"
 158
 159   CacheView
 160     *image_view,
 161     *threshold_view;
 162
 163   Image
 164     *threshold_image;
 165
 166   MagickBooleanType
 167     status;
 168
 169   MagickOffsetType
 170     progress;
 171
 172   MagickSizeType
 173     number_pixels;
 174
 175   ssize_t
 176     y;
 177
 178   /*
 179     Initialize threshold image attributes.
 180   */
 181   assert(image != (Image *) NULL);
 182   assert(image->signature == MagickSignature);
 183   if (image->debug != MagickFalse)
 184     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 185   assert(exception != (ExceptionInfo *) NULL);
 186   assert(exception->signature == MagickSignature);
 187   if ((width % 2) == 0)
 188     ThrowImageException(OptionError,"KernelWidthMustBeAnOddNumber");
 189   threshold_image=CloneImage(image,image->columns,image->rows,MagickTrue,
 190     exception);
 191   if (threshold_image == (Image *) NULL)
 192     return((Image *) NULL);
 193   status=SetImageStorageClass(threshold_image,DirectClass,exception);
 194   if (status == MagickFalse)
 195     {
 196       threshold_image=DestroyImage(threshold_image);
 197       return((Image *) NULL);
 198     }
 199   /*
 200     Threshold image.
 201   */
 202   status=MagickTrue;
 203   progress=0;
 204   number_pixels=(MagickSizeType) width*height;
 205   image_view=AcquireVirtualCacheView(image,exception);
 206   threshold_view=AcquireAuthenticCacheView(threshold_image,exception);
 207 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 208   #pragma omp parallel for schedule(static,4) shared(progress,status) \
 209     dynamic_number_threads(image,image->columns,image->rows,1)
 210 #endif
 211   for (y=0; y < (ssize_t) image->rows; y++)
 212   {
 213     register const Quantum
 214       *restrict p;
 215
 216     register Quantum
 217       *restrict q;
 218
 219     register ssize_t
 220       x;
 221
 222     ssize_t
 223       center;
 224
 225     if (status == MagickFalse)
 226       continue;
 227     p=GetCacheViewVirtualPixels(image_view,-((ssize_t) width/2L),y-(ssize_t)
 228       (height/2L),image->columns+width,height,exception);
 229     q=QueueCacheViewAuthenticPixels(threshold_view,0,y,threshold_image->columns,
 230       1,exception);
 231     if ((p == (const Quantum *) NULL) || (q == (Quantum *) NULL))
 232       {
 233         status=MagickFalse;
 234         continue;
 235       }
 236     center=(ssize_t) GetPixelChannels(image)*(image->columns+width)*(height/2L)+
 237       GetPixelChannels(image)*(width/2);
 238     for (x=0; x < (ssize_t) image->columns; x++)
 239     {
 240       register ssize_t
 241         i;
 242
 243       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 244       {
 245         double
 246           mean,
 247           pixel;
 248
 249         PixelChannel
 250           channel;
 251
 252         PixelTrait
 253           threshold_traits,
 254           traits;
 255
 256         register const Quantum
 257           *restrict pixels;
 258
 259         register ssize_t
 260           u;
 261
 262         ssize_t
 263           v;
 264
 265         channel=GetPixelChannelChannel(image,i);
 266         traits=GetPixelChannelTraits(image,channel);
 267         threshold_traits=GetPixelChannelTraits(threshold_image,channel);
 268         if ((traits == UndefinedPixelTrait) ||
 269             (threshold_traits == UndefinedPixelTrait))
 270           continue;
 271         if (((threshold_traits & CopyPixelTrait) != 0) ||
 272             (GetPixelMask(image,p) != 0))
 273           {
 274             SetPixelChannel(threshold_image,channel,p[center+i],q);
 275             continue;
 276           }
 277         pixels=p;
 278         pixel=0.0;
 279         for (v=0; v < (ssize_t) height; v++)
 280         {
 281           for (u=0; u < (ssize_t) width; u++)
 282           {
 283             pixel+=pixels[i];
 284             pixels+=GetPixelChannels(image);
 285           }
 286           pixels+=image->columns*GetPixelChannels(image);
 287         }
 288         mean=(double) (pixel/number_pixels+bias);
 289         SetPixelChannel(threshold_image,channel,(Quantum) ((double)
 290           p[center+i] <= mean ? 0 : QuantumRange),q);
 291       }
 292       p+=GetPixelChannels(image);
 293       q+=GetPixelChannels(threshold_image);
 294     }
 295     if (SyncCacheViewAuthenticPixels(threshold_view,exception) == MagickFalse)
 296       status=MagickFalse;
 297     if (image->progress_monitor != (MagickProgressMonitor) NULL)
 298       {
 299         MagickBooleanType
 300           proceed;
 301
 302 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 303         #pragma omp critical (MagickCore_AdaptiveThresholdImage)
 304 #endif
 305         proceed=SetImageProgress(image,AdaptiveThresholdImageTag,progress++,
 306           image->rows);
 307         if (proceed == MagickFalse)
 308           status=MagickFalse;
 309       }
 310   }
 311   threshold_image->type=image->type;
 312   threshold_view=DestroyCacheView(threshold_view);
 313   image_view=DestroyCacheView(image_view);
 314   if (status == MagickFalse)
 315     threshold_image=DestroyImage(threshold_image);
 316   return(threshold_image);
 317 }
 318 \f
 319 /*
 320 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 321 %                                                                             %
 322 %                                                                             %
 323 %                                                                             %
 324 %     B i l e v e l I m a g e                                                 %
 325 %                                                                             %
 326 %                                                                             %
 327 %                                                                             %
 328 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 329 %
 330 %  BilevelImage() changes the value of individual pixels based on the
 331 %  intensity of each pixel channel.  The result is a high-contrast image.
 332 %
 333 %  More precisely each channel value of the image is 'thresholded' so that if
 334 %  it is equal to or less than the given value it is set to zero, while any
 335 %  value greater than that give is set to it maximum or QuantumRange.
 336 %
 337 %  This function is what is used to implement the "-threshold" operator for
 338 %  the command line API.
 339 %
 340 %  If the default channel setting is given the image is thresholded using just
 341 %  the gray 'intensity' of the image, rather than the individual channels.
 342 %
 343 %  The format of the BilevelImage method is:
 344 %
 345 %      MagickBooleanType BilevelImage(Image *image,const double threshold,
 346 %        ExceptionInfo *exception)
 347 %
 348 %  A description of each parameter follows:
 349 %
 350 %    o image: the image.
 351 %
 352 %    o threshold: define the threshold values.
 353 %
 354 %    o exception: return any errors or warnings in this structure.
 355 %
 356 %  Aside: You can get the same results as operator using LevelImages()
 357 %  with the 'threshold' value for both the black_point and the white_point.
 358 %
 359 */
 360 MagickExport MagickBooleanType BilevelImage(Image *image,const double threshold,
 361   ExceptionInfo *exception)
 362 {
 363 #define ThresholdImageTag  "Threshold/Image"
 364
 365   CacheView
 366     *image_view;
 367
 368   MagickBooleanType
 369     status;
 370
 371   MagickOffsetType
 372     progress;
 373
 374   ssize_t
 375     y;
 376
 377   assert(image != (Image *) NULL);
 378   assert(image->signature == MagickSignature);
 379   if (image->debug != MagickFalse)
 380     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 381   if (SetImageStorageClass(image,DirectClass,exception) == MagickFalse)
 382     return(MagickFalse);
 383   /*
 384     Bilevel threshold image.
 385   */
 386   status=MagickTrue;
 387   progress=0;
 388   image_view=AcquireAuthenticCacheView(image,exception);
 389 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 390   #pragma omp parallel for schedule(static,4) shared(progress,status) \
 391     dynamic_number_threads(image,image->columns,image->rows,1)
 392 #endif
 393   for (y=0; y < (ssize_t) image->rows; y++)
 394   {
 395     register ssize_t
 396       x;
 397
 398     register Quantum
 399       *restrict q;
 400
 401     if (status == MagickFalse)
 402       continue;
 403     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
 404     if (q == (Quantum *) NULL)
 405       {
 406         status=MagickFalse;
 407         continue;
 408       }
 409     for (x=0; x < (ssize_t) image->columns; x++)
 410     {
 411       double
 412         pixel;
 413
 414       register ssize_t
 415         i;
 416
 417       if (GetPixelMask(image,q) != 0)
 418         {
 419           q+=GetPixelChannels(image);
 420           continue;
 421         }
 422       pixel=GetPixelIntensity(image,q);
 423       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 424       {
 425         PixelChannel
 426           channel;
 427
 428         PixelTrait
 429           traits;
 430
 431         channel=GetPixelChannelChannel(image,i);
 432         traits=GetPixelChannelTraits(image,channel);
 433         if ((traits & UpdatePixelTrait) == 0)
 434           continue;
 435         if (image->channel_mask != DefaultChannels)
 436           pixel=(double) q[i];
 437         q[i]=(Quantum) (pixel <= threshold ? 0 : QuantumRange);
 438       }
 439       q+=GetPixelChannels(image);
 440     }
 441     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
 442       status=MagickFalse;
 443     if (image->progress_monitor != (MagickProgressMonitor) NULL)
 444       {
 445         MagickBooleanType
 446           proceed;
 447
 448 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 449         #pragma omp critical (MagickCore_BilevelImage)
 450 #endif
 451         proceed=SetImageProgress(image,ThresholdImageTag,progress++,
 452           image->rows);
 453         if (proceed == MagickFalse)
 454           status=MagickFalse;
 455       }
 456   }
 457   image_view=DestroyCacheView(image_view);
 458   return(status);
 459 }
 460 \f
 461 /*
 462 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 463 %                                                                             %
 464 %                                                                             %
 465 %                                                                             %
 466 %     B l a c k T h r e s h o l d I m a g e                                   %
 467 %                                                                             %
 468 %                                                                             %
 469 %                                                                             %
 470 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 471 %
 472 %  BlackThresholdImage() is like ThresholdImage() but forces all pixels below
 473 %  the threshold into black while leaving all pixels at or above the threshold
 474 %  unchanged.
 475 %
 476 %  The format of the BlackThresholdImage method is:
 477 %
 478 %      MagickBooleanType BlackThresholdImage(Image *image,
 479 %        const char *threshold,ExceptionInfo *exception)
 480 %
 481 %  A description of each parameter follows:
 482 %
 483 %    o image: the image.
 484 %
 485 %    o threshold: define the threshold value.
 486 %
 487 %    o exception: return any errors or warnings in this structure.
 488 %
 489 */
 490 MagickExport MagickBooleanType BlackThresholdImage(Image *image,
 491   const char *thresholds,ExceptionInfo *exception)
 492 {
 493 #define ThresholdImageTag  "Threshold/Image"
 494
 495   CacheView
 496     *image_view;
 497
 498   GeometryInfo
 499     geometry_info;
 500
 501   MagickBooleanType
 502     status;
 503
 504   MagickOffsetType
 505     progress;
 506
 507   PixelInfo
 508     threshold;
 509
 510   MagickStatusType
 511     flags;
 512
 513   ssize_t
 514     y;
 515
 516   assert(image != (Image *) NULL);
 517   assert(image->signature == MagickSignature);
 518   if (image->debug != MagickFalse)
 519     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 520   if (thresholds == (const char *) NULL)
 521     return(MagickTrue);
 522   if (SetImageStorageClass(image,DirectClass,exception) == MagickFalse)
 523     return(MagickFalse);
 524   if (IsGrayColorspace(image->colorspace) != MagickFalse)
 525     (void) TransformImageColorspace(image,RGBColorspace,exception);
 526   GetPixelInfo(image,&threshold);
 527   flags=ParseGeometry(thresholds,&geometry_info);
 528   threshold.red=geometry_info.rho;
 529   threshold.green=geometry_info.rho;
 530   threshold.blue=geometry_info.rho;
 531   threshold.black=geometry_info.rho;
 532   threshold.alpha=100.0;
 533   if ((flags & SigmaValue) != 0)
 534     threshold.green=geometry_info.sigma;
 535   if ((flags & XiValue) != 0)
 536     threshold.blue=geometry_info.xi;
 537   if ((flags & PsiValue) != 0)
 538     threshold.alpha=geometry_info.psi;
 539   if (threshold.colorspace == CMYKColorspace)
 540     {
 541       if ((flags & PsiValue) != 0)
 542         threshold.black=geometry_info.psi;
 543       if ((flags & ChiValue) != 0)
 544         threshold.alpha=geometry_info.chi;
 545     }
 546   if ((flags & PercentValue) != 0)
 547     {
 548       threshold.red*=(QuantumRange/100.0);
 549       threshold.green*=(QuantumRange/100.0);
 550       threshold.blue*=(QuantumRange/100.0);
 551       threshold.black*=(QuantumRange/100.0);
 552       threshold.alpha*=(QuantumRange/100.0);
 553     }
 554   /*
 555     White threshold image.
 556   */
 557   status=MagickTrue;
 558   progress=0;
 559   image_view=AcquireAuthenticCacheView(image,exception);
 560 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 561   #pragma omp parallel for schedule(static,4) shared(progress,status) \
 562     dynamic_number_threads(image,image->columns,image->rows,1)
 563 #endif
 564   for (y=0; y < (ssize_t) image->rows; y++)
 565   {
 566     register ssize_t
 567       x;
 568
 569     register Quantum
 570       *restrict q;
 571
 572     if (status == MagickFalse)
 573       continue;
 574     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
 575     if (q == (Quantum *) NULL)
 576       {
 577         status=MagickFalse;
 578         continue;
 579       }
 580     for (x=0; x < (ssize_t) image->columns; x++)
 581     {
 582       double
 583         pixel;
 584
 585       register ssize_t
 586         i;
 587
 588       if (GetPixelMask(image,q) != 0)
 589         {
 590           q+=GetPixelChannels(image);
 591           continue;
 592         }
 593       pixel=GetPixelIntensity(image,q);
 594       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 595       {
 596         PixelChannel
 597           channel;
 598
 599         PixelTrait
 600           traits;
 601
 602         channel=GetPixelChannelChannel(image,i);
 603         traits=GetPixelChannelTraits(image,channel);
 604         if ((traits & UpdatePixelTrait) == 0)
 605           continue;
 606         if (image->channel_mask != DefaultChannels)
 607           pixel=(double) q[i];
 608         if (pixel <= GetPixelInfoChannel(&threshold,channel))
 609           q[i]=0;
 610       }
 611       q+=GetPixelChannels(image);
 612     }
 613     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
 614       status=MagickFalse;
 615     if (image->progress_monitor != (MagickProgressMonitor) NULL)
 616       {
 617         MagickBooleanType
 618           proceed;
 619
 620 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 621         #pragma omp critical (MagickCore_BlackThresholdImage)
 622 #endif
 623         proceed=SetImageProgress(image,ThresholdImageTag,progress++,
 624           image->rows);
 625         if (proceed == MagickFalse)
 626           status=MagickFalse;
 627       }
 628   }
 629   image_view=DestroyCacheView(image_view);
 630   return(status);
 631 }
 632 \f
 633 /*
 634 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 635 %                                                                             %
 636 %                                                                             %
 637 %                                                                             %
 638 %     C l a m p I m a g e                                                     %
 639 %                                                                             %
 640 %                                                                             %
 641 %                                                                             %
 642 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 643 %
 644 %  ClampImage() restricts the color range from 0 to the quantum depth.
 645 %
 646 %  The format of the ClampImage method is:
 647 %
 648 %      MagickBooleanType ClampImage(Image *image,ExceptionInfo *exception)
 649 %
 650 %  A description of each parameter follows:
 651 %
 652 %    o image: the image.
 653 %
 654 %    o exception: return any errors or warnings in this structure.
 655 %
 656 */
 657
 658 static inline Quantum ClampToUnsignedQuantum(const Quantum quantum)
 659 {
 660   if (quantum <= 0)
 661     return(0);
 662   if (quantum >= QuantumRange)
 663     return(QuantumRange);
 664   return(quantum);
 665 }
 666
 667 MagickExport MagickBooleanType ClampImage(Image *image,ExceptionInfo *exception)
 668 {
 669 #if !defined(MAGICKCORE_HDRI_SUPPORT)
 670   return(MagickTrue);
 671 #else
 672 #define ClampImageTag  "Clamp/Image"
 673
 674   CacheView
 675     *image_view;
 676
 677   MagickBooleanType
 678     status;
 679
 680   MagickOffsetType
 681     progress;
 682
 683   ssize_t
 684     y;
 685
 686   assert(image != (Image *) NULL);
 687   assert(image->signature == MagickSignature);
 688   if (image->debug != MagickFalse)
 689     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 690   if (image->storage_class == PseudoClass)
 691     {
 692       register ssize_t
 693         i;
 694
 695       register PixelInfo
 696         *restrict q;
 697
 698       q=image->colormap;
 699       for (i=0; i < (ssize_t) image->colors; i++)
 700       {
 701         q->red=(double) ClampToUnsignedQuantum(ClampToQuantum(q->red));
 702         q->green=(double) ClampToUnsignedQuantum(ClampToQuantum(q->green));
 703         q->blue=(double) ClampToUnsignedQuantum(ClampToQuantum(q->blue));
 704         q->alpha=(double) ClampToUnsignedQuantum(ClampToQuantum(q->alpha));
 705         q++;
 706       }
 707       return(SyncImage(image,exception));
 708     }
 709   /*
 710     Clamp image.
 711   */
 712   status=MagickTrue;
 713   progress=0;
 714   image_view=AcquireAuthenticCacheView(image,exception);
 715 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 716   #pragma omp parallel for schedule(static,4) shared(progress,status) \
 717     dynamic_number_threads(image,image->columns,image->rows,1)
 718 #endif
 719   for (y=0; y < (ssize_t) image->rows; y++)
 720   {
 721     register ssize_t
 722       x;
 723
 724     register Quantum
 725       *restrict q;
 726
 727     if (status == MagickFalse)
 728       continue;
 729     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
 730     if (q == (Quantum *) NULL)
 731       {
 732         status=MagickFalse;
 733         continue;
 734       }
 735     for (x=0; x < (ssize_t) image->columns; x++)
 736     {
 737       register ssize_t
 738         i;
 739
 740       if (GetPixelMask(image,q) != 0)
 741         {
 742           q+=GetPixelChannels(image);
 743           continue;
 744         }
 745       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
 746       {
 747         PixelChannel
 748           channel;
 749
 750         PixelTrait
 751           traits;
 752
 753         channel=GetPixelChannelChannel(image,i);
 754         traits=GetPixelChannelTraits(image,channel);
 755         if (traits == UndefinedPixelTrait)
 756           continue;
 757         q[i]=ClampToUnsignedQuantum(q[i]);
 758       }
 759       q+=GetPixelChannels(image);
 760     }
 761     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
 762       status=MagickFalse;
 763     if (image->progress_monitor != (MagickProgressMonitor) NULL)
 764       {
 765         MagickBooleanType
 766           proceed;
 767
 768 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 769         #pragma omp critical (MagickCore_ClampImage)
 770 #endif
 771         proceed=SetImageProgress(image,ClampImageTag,progress++,image->rows);
 772         if (proceed == MagickFalse)
 773           status=MagickFalse;
 774       }
 775   }
 776   image_view=DestroyCacheView(image_view);
 777   return(status);
 778 #endif
 779 }
 780 \f
 781 /*
 782 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 783 %                                                                             %
 784 %                                                                             %
 785 %                                                                             %
 786 %  D e s t r o y T h r e s h o l d M a p                                      %
 787 %                                                                             %
 788 %                                                                             %
 789 %                                                                             %
 790 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 791 %
 792 %  DestroyThresholdMap() de-allocate the given ThresholdMap
 793 %
 794 %  The format of the ListThresholdMaps method is:
 795 %
 796 %      ThresholdMap *DestroyThresholdMap(Threshold *map)
 797 %
 798 %  A description of each parameter follows.
 799 %
 800 %    o map:    Pointer to the Threshold map to destroy
 801 %
 802 */
 803 MagickExport ThresholdMap *DestroyThresholdMap(ThresholdMap *map)
 804 {
 805   assert(map != (ThresholdMap *) NULL);
 806   if (map->map_id != (char *) NULL)
 807     map->map_id=DestroyString(map->map_id);
 808   if (map->description != (char *) NULL)
 809     map->description=DestroyString(map->description);
 810   if (map->levels != (ssize_t *) NULL)
 811     map->levels=(ssize_t *) RelinquishMagickMemory(map->levels);
 812   map=(ThresholdMap *) RelinquishMagickMemory(map);
 813   return(map);
 814 }
 815 \f
 816 /*
 817 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 818 %                                                                             %
 819 %                                                                             %
 820 %                                                                             %
 821 %  G e t T h r e s h o l d M a p                                              %
 822 %                                                                             %
 823 %                                                                             %
 824 %                                                                             %
 825 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 826 %
 827 %  GetThresholdMap() loads and searches one or more threshold map files for the
 828 %  map matching the given name or alias.
 829 %
 830 %  The format of the GetThresholdMap method is:
 831 %
 832 %      ThresholdMap *GetThresholdMap(const char *map_id,
 833 %        ExceptionInfo *exception)
 834 %
 835 %  A description of each parameter follows.
 836 %
 837 %    o map_id:  ID of the map to look for.
 838 %
 839 %    o exception: return any errors or warnings in this structure.
 840 %
 841 */
 842 MagickExport ThresholdMap *GetThresholdMap(const char *map_id,
 843   ExceptionInfo *exception)
 844 {
 845   const StringInfo
 846     *option;
 847
 848   LinkedListInfo
 849     *options;
 850
 851   ThresholdMap
 852     *map;
 853
 854   map=(ThresholdMap *)NULL;
 855   options=GetConfigureOptions(ThresholdsFilename,exception);
 856   while ((option=(const StringInfo *) GetNextValueInLinkedList(options)) !=
 857          (const StringInfo *) NULL && (map == (ThresholdMap *) NULL))
 858     map=GetThresholdMapFile((const char *) GetStringInfoDatum(option),
 859       GetStringInfoPath(option),map_id,exception);
 860   options=DestroyConfigureOptions(options);
 861   return(map);
 862 }
 863 \f
 864 /*
 865 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 866 %                                                                             %
 867 %                                                                             %
 868 %                                                                             %
 869 +  G e t T h r e s h o l d M a p F i l e                                      %
 870 %                                                                             %
 871 %                                                                             %
 872 %                                                                             %
 873 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 874 %
 875 %  GetThresholdMapFile() look for a given threshold map name or alias in the
 876 %  given XML file data, and return the allocated the map when found.
 877 %
 878 %  The format of the ListThresholdMaps method is:
 879 %
 880 %      ThresholdMap *GetThresholdMap(const char *xml,const char *filename,
 881 %         const char *map_id,ExceptionInfo *exception)
 882 %
 883 %  A description of each parameter follows.
 884 %
 885 %    o xml:  The threshold map list in XML format.
 886 %
 887 %    o filename:  The threshold map XML filename.
 888 %
 889 %    o map_id:  ID of the map to look for in XML list.
 890 %
 891 %    o exception: return any errors or warnings in this structure.
 892 %
 893 */
 894 static ThresholdMap *GetThresholdMapFile(const char *xml,
 895   const char *filename,const char *map_id,ExceptionInfo *exception)
 896 {
 897   char
 898     *p;
 899
 900   const char
 901     *attribute,
 902     *content;
 903
 904   double
 905     value;
 906
 907   register ssize_t
 908     i;
 909
 910   ThresholdMap
 911     *map;
 912
 913   XMLTreeInfo
 914     *description,
 915     *levels,
 916     *threshold,
 917     *thresholds;
 918
 919   (void) LogMagickEvent(ConfigureEvent,GetMagickModule(),
 920     "Loading threshold map file \"%s\" ...",filename);
 921   map=(ThresholdMap *) NULL;
 922   thresholds=NewXMLTree(xml,exception);
 923   if (thresholds == (XMLTreeInfo *) NULL)
 924     return(map);
 925   for (threshold=GetXMLTreeChild(thresholds,"threshold");
 926        threshold != (XMLTreeInfo *) NULL;
 927        threshold=GetNextXMLTreeTag(threshold))
 928   {
 929     attribute=GetXMLTreeAttribute(threshold,"map");
 930     if ((attribute != (char *) NULL) && (LocaleCompare(map_id,attribute) == 0))
 931       break;
 932     attribute=GetXMLTreeAttribute(threshold,"alias");
 933     if ((attribute != (char *) NULL) && (LocaleCompare(map_id,attribute) == 0))
 934       break;
 935   }
 936   if (threshold == (XMLTreeInfo *) NULL)
 937     return(map);
 938   description=GetXMLTreeChild(threshold,"description");
 939   if (description == (XMLTreeInfo *) NULL)
 940     {
 941       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 942         "XmlMissingElement", "<description>, map \"%s\"",map_id);
 943       thresholds=DestroyXMLTree(thresholds);
 944       return(map);
 945     }
 946   levels=GetXMLTreeChild(threshold,"levels");
 947   if (levels == (XMLTreeInfo *) NULL)
 948     {
 949       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 950         "XmlMissingElement", "<levels>, map \"%s\"", map_id);
 951       thresholds=DestroyXMLTree(thresholds);
 952       return(map);
 953     }
 954   map=(ThresholdMap *) AcquireMagickMemory(sizeof(ThresholdMap));
 955   if (map == (ThresholdMap *) NULL)
 956     ThrowFatalException(ResourceLimitFatalError,"UnableToAcquireThresholdMap");
 957   map->map_id=(char *) NULL;
 958   map->description=(char *) NULL;
 959   map->levels=(ssize_t *) NULL;
 960   attribute=GetXMLTreeAttribute(threshold,"map");
 961   if (attribute != (char *) NULL)
 962     map->map_id=ConstantString(attribute);
 963   content=GetXMLTreeContent(description);
 964   if (content != (char *) NULL)
 965     map->description=ConstantString(content);
 966   attribute=GetXMLTreeAttribute(levels,"width");
 967   if (attribute == (char *) NULL)
 968     {
 969       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 970         "XmlMissingAttribute", "<levels width>, map \"%s\"",map_id);
 971       thresholds=DestroyXMLTree(thresholds);
 972       map=DestroyThresholdMap(map);
 973       return(map);
 974     }
 975   map->width=StringToUnsignedLong(attribute);
 976   if (map->width == 0)
 977     {
 978       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 979        "XmlInvalidAttribute", "<levels width>, map \"%s\"",map_id);
 980       thresholds=DestroyXMLTree(thresholds);
 981       map=DestroyThresholdMap(map);
 982       return(map);
 983     }
 984   attribute=GetXMLTreeAttribute(levels,"height");
 985   if (attribute == (char *) NULL)
 986     {
 987       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 988         "XmlMissingAttribute", "<levels height>, map \"%s\"",map_id);
 989       thresholds=DestroyXMLTree(thresholds);
 990       map=DestroyThresholdMap(map);
 991       return(map);
 992     }
 993   map->height=StringToUnsignedLong(attribute);
 994   if (map->height == 0)
 995     {
 996       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
 997         "XmlInvalidAttribute", "<levels height>, map \"%s\"",map_id);
 998       thresholds=DestroyXMLTree(thresholds);
 999       map=DestroyThresholdMap(map);
1000       return(map);
1001     }
1002   attribute=GetXMLTreeAttribute(levels,"divisor");
1003   if (attribute == (char *) NULL)
1004     {
1005       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1006         "XmlMissingAttribute", "<levels divisor>, map \"%s\"",map_id);
1007       thresholds=DestroyXMLTree(thresholds);
1008       map=DestroyThresholdMap(map);
1009       return(map);
1010     }
1011   map->divisor=(ssize_t) StringToLong(attribute);
1012   if (map->divisor < 2)
1013     {
1014       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1015         "XmlInvalidAttribute", "<levels divisor>, map \"%s\"",map_id);
1016       thresholds=DestroyXMLTree(thresholds);
1017       map=DestroyThresholdMap(map);
1018       return(map);
1019     }
1020   content=GetXMLTreeContent(levels);
1021   if (content == (char *) NULL)
1022     {
1023       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1024         "XmlMissingContent", "<levels>, map \"%s\"",map_id);
1025       thresholds=DestroyXMLTree(thresholds);
1026       map=DestroyThresholdMap(map);
1027       return(map);
1028     }
1029   map->levels=(ssize_t *) AcquireQuantumMemory((size_t) map->width,map->height*
1030     sizeof(*map->levels));
1031   if (map->levels == (ssize_t *) NULL)
1032     ThrowFatalException(ResourceLimitFatalError,"UnableToAcquireThresholdMap");
1033   for (i=0; i < (ssize_t) (map->width*map->height); i++)
1034   {
1035     map->levels[i]=(ssize_t) strtol(content,&p,10);
1036     if (p == content)
1037       {
1038         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1039           "XmlInvalidContent", "<level> too few values, map \"%s\"",map_id);
1040         thresholds=DestroyXMLTree(thresholds);
1041         map=DestroyThresholdMap(map);
1042         return(map);
1043       }
1044     if ((map->levels[i] < 0) || (map->levels[i] > map->divisor))
1045       {
1046         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1047           "XmlInvalidContent", "<level> %.20g out of range, map \"%s\"",
1048           (double) map->levels[i],map_id);
1049         thresholds=DestroyXMLTree(thresholds);
1050         map=DestroyThresholdMap(map);
1051         return(map);
1052       }
1053     content=p;
1054   }
1055   value=(double) strtol(content,&p,10);
1056   (void) value;
1057   if (p != content)
1058     {
1059       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1060         "XmlInvalidContent", "<level> too many values, map \"%s\"",map_id);
1061      thresholds=DestroyXMLTree(thresholds);
1062      map=DestroyThresholdMap(map);
1063      return(map);
1064    }
1065   thresholds=DestroyXMLTree(thresholds);
1066   return(map);
1067 }
1068 \f
1069 /*
1070 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1071 %                                                                             %
1072 %                                                                             %
1073 %                                                                             %
1074 +  L i s t T h r e s h o l d M a p F i l e                                    %
1075 %                                                                             %
1076 %                                                                             %
1077 %                                                                             %
1078 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1079 %
1080 %  ListThresholdMapFile() lists the threshold maps and their descriptions
1081 %  in the given XML file data.
1082 %
1083 %  The format of the ListThresholdMaps method is:
1084 %
1085 %      MagickBooleanType ListThresholdMaps(FILE *file,const char*xml,
1086 %         const char *filename,ExceptionInfo *exception)
1087 %
1088 %  A description of each parameter follows.
1089 %
1090 %    o file:  An pointer to the output FILE.
1091 %
1092 %    o xml:  The threshold map list in XML format.
1093 %
1094 %    o filename:  The threshold map XML filename.
1095 %
1096 %    o exception: return any errors or warnings in this structure.
1097 %
1098 */
1099 MagickBooleanType ListThresholdMapFile(FILE *file,const char *xml,
1100   const char *filename,ExceptionInfo *exception)
1101 {
1102   const char
1103     *alias,
1104     *content,
1105     *map;
1106
1107   XMLTreeInfo
1108     *description,
1109     *threshold,
1110     *thresholds;
1111
1112   assert( xml != (char *)NULL );
1113   assert( file != (FILE *)NULL );
1114   (void) LogMagickEvent(ConfigureEvent,GetMagickModule(),
1115     "Loading threshold map file \"%s\" ...",filename);
1116   thresholds=NewXMLTree(xml,exception);
1117   if ( thresholds == (XMLTreeInfo *)NULL )
1118     return(MagickFalse);
1119   (void) FormatLocaleFile(file,"%-16s %-12s %s\n","Map","Alias","Description");
1120   (void) FormatLocaleFile(file,
1121     "----------------------------------------------------\n");
1122   threshold=GetXMLTreeChild(thresholds,"threshold");
1123   for ( ; threshold != (XMLTreeInfo *) NULL;
1124           threshold=GetNextXMLTreeTag(threshold))
1125   {
1126     map=GetXMLTreeAttribute(threshold,"map");
1127     if (map == (char *) NULL)
1128       {
1129         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1130           "XmlMissingAttribute", "<map>");
1131         thresholds=DestroyXMLTree(thresholds);
1132         return(MagickFalse);
1133       }
1134     alias=GetXMLTreeAttribute(threshold,"alias");
1135     description=GetXMLTreeChild(threshold,"description");
1136     if (description == (XMLTreeInfo *) NULL)
1137       {
1138         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1139           "XmlMissingElement", "<description>, map \"%s\"",map);
1140         thresholds=DestroyXMLTree(thresholds);
1141         return(MagickFalse);
1142       }
1143     content=GetXMLTreeContent(description);
1144     if (content == (char *) NULL)
1145       {
1146         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1147           "XmlMissingContent", "<description>, map \"%s\"", map);
1148         thresholds=DestroyXMLTree(thresholds);
1149         return(MagickFalse);
1150       }
1151     (void) FormatLocaleFile(file,"%-16s %-12s %s\n",map,alias ? alias : "",
1152       content);
1153   }
1154   thresholds=DestroyXMLTree(thresholds);
1155   return(MagickTrue);
1156 }
1157 \f
1158 /*
1159 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1160 %                                                                             %
1161 %                                                                             %
1162 %                                                                             %
1163 %  L i s t T h r e s h o l d M a p s                                          %
1164 %                                                                             %
1165 %                                                                             %
1166 %                                                                             %
1167 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1168 %
1169 %  ListThresholdMaps() lists the threshold maps and their descriptions
1170 %  as defined by "threshold.xml" to a file.
1171 %
1172 %  The format of the ListThresholdMaps method is:
1173 %
1174 %      MagickBooleanType ListThresholdMaps(FILE *file,ExceptionInfo *exception)
1175 %
1176 %  A description of each parameter follows.
1177 %
1178 %    o file:  An pointer to the output FILE.
1179 %
1180 %    o exception: return any errors or warnings in this structure.
1181 %
1182 */
1183 MagickExport MagickBooleanType ListThresholdMaps(FILE *file,
1184   ExceptionInfo *exception)
1185 {
1186   const StringInfo
1187     *option;
1188
1189   LinkedListInfo
1190     *options;
1191
1192   MagickStatusType
1193     status;
1194
1195   status=MagickFalse;
1196   if (file == (FILE *) NULL)
1197     file=stdout;
1198   options=GetConfigureOptions(ThresholdsFilename,exception);
1199   (void) FormatLocaleFile(file,
1200     "\n   Threshold Maps for Ordered Dither Operations\n");
1201   while ((option=(const StringInfo *) GetNextValueInLinkedList(options)) !=
1202          (const StringInfo *) NULL)
1203   {
1204     (void) FormatLocaleFile(file,"\nPATH: %s\n\n",GetStringInfoPath(option));
1205     status|=ListThresholdMapFile(file,(const char *) GetStringInfoDatum(option),
1206       GetStringInfoPath(option),exception);
1207   }
1208   options=DestroyConfigureOptions(options);
1209   return(status != 0 ? MagickTrue : MagickFalse);
1210 }
1211 \f
1212 /*
1213 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1214 %                                                                             %
1215 %                                                                             %
1216 %                                                                             %
1217 %     O r d e r e d P o s t e r i z e I m a g e                               %
1218 %                                                                             %
1219 %                                                                             %
1220 %                                                                             %
1221 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1222 %
1223 %  OrderedPosterizeImage() will perform a ordered dither based on a number
1224 %  of pre-defined dithering threshold maps, but over multiple intensity
1225 %  levels, which can be different for different channels, according to the
1226 %  input argument.
1227 %
1228 %  The format of the OrderedPosterizeImage method is:
1229 %
1230 %      MagickBooleanType OrderedPosterizeImage(Image *image,
1231 %        const char *threshold_map,ExceptionInfo *exception)
1232 %
1233 %  A description of each parameter follows:
1234 %
1235 %    o image: the image.
1236 %
1237 %    o threshold_map: A string containing the name of the threshold dither
1238 %      map to use, followed by zero or more numbers representing the number
1239 %      of color levels tho dither between.
1240 %
1241 %      Any level number less than 2 will be equivalent to 2, and means only
1242 %      binary dithering will be applied to each color channel.
1243 %
1244 %      No numbers also means a 2 level (bitmap) dither will be applied to all
1245 %      channels, while a single number is the number of levels applied to each
1246 %      channel in sequence.  More numbers will be applied in turn to each of
1247 %      the color channels.
1248 %
1249 %      For example: "o3x3,6" will generate a 6 level posterization of the
1250 %      image with a ordered 3x3 diffused pixel dither being applied between
1251 %      each level. While checker,8,8,4 will produce a 332 colormaped image
1252 %      with only a single checkerboard hash pattern (50% grey) between each
1253 %      color level, to basically double the number of color levels with
1254 %      a bare minimim of dithering.
1255 %
1256 %    o exception: return any errors or warnings in this structure.
1257 %
1258 */
1259 MagickExport MagickBooleanType OrderedPosterizeImage(Image *image,
1260   const char *threshold_map,ExceptionInfo *exception)
1261 {
1262 #define DitherImageTag  "Dither/Image"
1263
1264   CacheView
1265     *image_view;
1266
1267   char
1268     token[MaxTextExtent];
1269
1270   const char
1271     *p;
1272
1273   MagickBooleanType
1274     status;
1275
1276   MagickOffsetType
1277     progress;
1278
1279   double
1280     levels[CompositePixelChannel];
1281
1282   register ssize_t
1283     i;
1284
1285   ssize_t
1286     y;
1287
1288   ThresholdMap
1289     *map;
1290
1291   assert(image != (Image *) NULL);
1292   assert(image->signature == MagickSignature);
1293   if (image->debug != MagickFalse)
1294     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1295   assert(exception != (ExceptionInfo *) NULL);
1296   assert(exception->signature == MagickSignature);
1297   if (threshold_map == (const char *) NULL)
1298     return(MagickTrue);
1299   p=(char *) threshold_map;
1300   while (((isspace((int) ((unsigned char) *p)) != 0) || (*p == ',')) &&
1301          (*p != '\0'))
1302     p++;
1303   threshold_map=p;
1304   while (((isspace((int) ((unsigned char) *p)) == 0) && (*p != ',')) &&
1305          (*p != '\0'))
1306   {
1307     if ((p-threshold_map) >= (MaxTextExtent-1))
1308       break;
1309     token[p-threshold_map]=(*p);
1310     p++;
1311   }
1312   token[p-threshold_map]='\0';
1313   map=GetThresholdMap(token,exception);
1314   if (map == (ThresholdMap *) NULL)
1315     {
1316       (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
1317         "InvalidArgument","%s : '%s'","ordered-dither",threshold_map);
1318       return(MagickFalse);
1319     }
1320   for (i=0; i < MaxPixelChannels; i++)
1321     levels[i]=2.0;
1322   p=strchr((char *) threshold_map,',');
1323   if ((p != (char *) NULL) && (isdigit((int) ((unsigned char) *(++p))) != 0))
1324     for (i=0; (*p != '\0') && (i < MaxPixelChannels); i++)
1325     {
1326       GetMagickToken(p,&p,token);
1327       if (*token == ',')
1328         GetMagickToken(p,&p,token);
1329       levels[i]=StringToDouble(token,(char **) NULL);
1330     }
1331   for (i=0; i < MaxPixelChannels; i++)
1332     if (fabs(levels[i]) >= 1)
1333       levels[i]-=1.0;
1334   if (SetImageStorageClass(image,DirectClass,exception) == MagickFalse)
1335     return(MagickFalse);
1336   status=MagickTrue;
1337   progress=0;
1338   image_view=AcquireAuthenticCacheView(image,exception);
1339 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1340   #pragma omp parallel for schedule(static,4) shared(progress,status) \
1341     dynamic_number_threads(image,image->columns,image->rows,1)
1342 #endif
1343   for (y=0; y < (ssize_t) image->rows; y++)
1344   {
1345     register ssize_t
1346       x;
1347
1348     register Quantum
1349       *restrict q;
1350
1351     if (status == MagickFalse)
1352       continue;
1353     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1354     if (q == (Quantum *) NULL)
1355       {
1356         status=MagickFalse;
1357         continue;
1358       }
1359     for (x=0; x < (ssize_t) image->columns; x++)
1360     {
1361       register ssize_t
1362         i;
1363
1364       ssize_t
1365         n;
1366
1367       n=0;
1368       if (GetPixelMask(image,q) != 0)
1369         {
1370           q+=GetPixelChannels(image);
1371           continue;
1372         }
1373       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1374       {
1375         PixelChannel
1376           channel;
1377
1378         PixelTrait
1379           traits;
1380
1381         ssize_t
1382           level,
1383           threshold;
1384
1385         channel=GetPixelChannelChannel(image,i);
1386         traits=GetPixelChannelTraits(image,channel);
1387         if ((traits & UpdatePixelTrait) == 0)
1388           continue;
1389         if (fabs(levels[n++]) < MagickEpsilon)
1390           continue;
1391         threshold=(ssize_t) (QuantumScale*q[i]*(levels[n]*(map->divisor-1)+1));
1392         level=threshold/(map->divisor-1);
1393         threshold-=level*(map->divisor-1);
1394         q[i]=ClampToQuantum((double) (level+(threshold >=
1395           map->levels[(x % map->width)+map->width*(y % map->height)]))*
1396           QuantumRange/levels[n]);
1397         n++;
1398       }
1399       q+=GetPixelChannels(image);
1400     }
1401     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1402       status=MagickFalse;
1403     if (image->progress_monitor != (MagickProgressMonitor) NULL)
1404       {
1405         MagickBooleanType
1406           proceed;
1407
1408 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1409         #pragma omp critical (MagickCore_OrderedPosterizeImage)
1410 #endif
1411         proceed=SetImageProgress(image,DitherImageTag,progress++,image->rows);
1412         if (proceed == MagickFalse)
1413           status=MagickFalse;
1414       }
1415   }
1416   image_view=DestroyCacheView(image_view);
1417   map=DestroyThresholdMap(map);
1418   return(MagickTrue);
1419 }
1420 \f
1421 /*
1422 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1423 %                                                                             %
1424 %                                                                             %
1425 %                                                                             %
1426 %     R a n d o m T h r e s h o l d I m a g e                                 %
1427 %                                                                             %
1428 %                                                                             %
1429 %                                                                             %
1430 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1431 %
1432 %  RandomThresholdImage() changes the value of individual pixels based on the
1433 %  intensity of each pixel compared to a random threshold.  The result is a
1434 %  low-contrast, two color image.
1435 %
1436 %  The format of the RandomThresholdImage method is:
1437 %
1438 %      MagickBooleanType RandomThresholdImage(Image *image,
1439 %        const char *thresholds,ExceptionInfo *exception)
1440 %
1441 %  A description of each parameter follows:
1442 %
1443 %    o image: the image.
1444 %
1445 %    o thresholds: a geometry string containing low,high thresholds.  If the
1446 %      string contains 2x2, 3x3, or 4x4, an ordered dither of order 2, 3, or 4
1447 %      is performed instead.
1448 %
1449 %    o exception: return any errors or warnings in this structure.
1450 %
1451 */
1452 MagickExport MagickBooleanType RandomThresholdImage(Image *image,
1453   const char *thresholds,ExceptionInfo *exception)
1454 {
1455 #define ThresholdImageTag  "Threshold/Image"
1456
1457   CacheView
1458     *image_view;
1459
1460   GeometryInfo
1461     geometry_info;
1462
1463   MagickStatusType
1464     flags;
1465
1466   MagickBooleanType
1467     status;
1468
1469   MagickOffsetType
1470     progress;
1471
1472   PixelInfo
1473     threshold;
1474
1475   double
1476     min_threshold,
1477     max_threshold;
1478
1479   RandomInfo
1480     **restrict random_info;
1481
1482   ssize_t
1483     y;
1484
1485   unsigned long
1486     key;
1487
1488   assert(image != (Image *) NULL);
1489   assert(image->signature == MagickSignature);
1490   if (image->debug != MagickFalse)
1491     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1492   assert(exception != (ExceptionInfo *) NULL);
1493   assert(exception->signature == MagickSignature);
1494   if (thresholds == (const char *) NULL)
1495     return(MagickTrue);
1496   if (SetImageStorageClass(image,DirectClass,exception) == MagickFalse)
1497     return(MagickFalse);
1498   GetPixelInfo(image,&threshold);
1499   min_threshold=0.0;
1500   max_threshold=(double) QuantumRange;
1501   flags=ParseGeometry(thresholds,&geometry_info);
1502   min_threshold=geometry_info.rho;
1503   max_threshold=geometry_info.sigma;
1504   if ((flags & SigmaValue) == 0)
1505     max_threshold=min_threshold;
1506   if (strchr(thresholds,'%') != (char *) NULL)
1507     {
1508       max_threshold*=(double) (0.01*QuantumRange);
1509       min_threshold*=(double) (0.01*QuantumRange);
1510     }
1511   /*
1512     Random threshold image.
1513   */
1514   status=MagickTrue;
1515   progress=0;
1516   random_info=AcquireRandomInfoThreadSet();
1517   key=GetRandomSecretKey(random_info[0]);
1518   image_view=AcquireAuthenticCacheView(image,exception);
1519 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1520   #pragma omp parallel for schedule(static,4) shared(progress,status) \
1521     dynamic_number_threads(image,image->columns,image->rows,key == ~0UL)
1522 #endif
1523   for (y=0; y < (ssize_t) image->rows; y++)
1524   {
1525     const int
1526       id = GetOpenMPThreadId();
1527
1528     register Quantum
1529       *restrict q;
1530
1531     register ssize_t
1532       x;
1533
1534     if (status == MagickFalse)
1535       continue;
1536     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1537     if (q == (Quantum *) NULL)
1538       {
1539         status=MagickFalse;
1540         continue;
1541       }
1542     for (x=0; x < (ssize_t) image->columns; x++)
1543     {
1544       register ssize_t
1545         i;
1546
1547       if (GetPixelMask(image,q) != 0)
1548         {
1549           q+=GetPixelChannels(image);
1550           continue;
1551         }
1552       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1553       {
1554         double
1555           threshold;
1556
1557         PixelChannel
1558           channel;
1559
1560         PixelTrait
1561           traits;
1562
1563         channel=GetPixelChannelChannel(image,i);
1564         traits=GetPixelChannelTraits(image,channel);
1565         if ((traits & UpdatePixelTrait) == 0)
1566           continue;
1567         if ((double) q[i] < min_threshold)
1568           threshold=min_threshold;
1569         else
1570           if ((double) q[i] > max_threshold)
1571             threshold=max_threshold;
1572           else
1573             threshold=(double) (QuantumRange*
1574               GetPseudoRandomValue(random_info[id]));
1575         q[i]=(double) q[i] <= threshold ? 0 : QuantumRange;
1576       }
1577       q+=GetPixelChannels(image);
1578     }
1579     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1580       status=MagickFalse;
1581     if (image->progress_monitor != (MagickProgressMonitor) NULL)
1582       {
1583         MagickBooleanType
1584           proceed;
1585
1586 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1587         #pragma omp critical (MagickCore_RandomThresholdImage)
1588 #endif
1589         proceed=SetImageProgress(image,ThresholdImageTag,progress++,
1590           image->rows);
1591         if (proceed == MagickFalse)
1592           status=MagickFalse;
1593       }
1594   }
1595   image_view=DestroyCacheView(image_view);
1596   random_info=DestroyRandomInfoThreadSet(random_info);
1597   return(status);
1598 }
1599 \f
1600 /*
1601 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1602 %                                                                             %
1603 %                                                                             %
1604 %                                                                             %
1605 %     W h i t e T h r e s h o l d I m a g e                                   %
1606 %                                                                             %
1607 %                                                                             %
1608 %                                                                             %
1609 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1610 %
1611 %  WhiteThresholdImage() is like ThresholdImage() but forces all pixels above
1612 %  the threshold into white while leaving all pixels at or below the threshold
1613 %  unchanged.
1614 %
1615 %  The format of the WhiteThresholdImage method is:
1616 %
1617 %      MagickBooleanType WhiteThresholdImage(Image *image,
1618 %        const char *threshold,ExceptionInfo *exception)
1619 %
1620 %  A description of each parameter follows:
1621 %
1622 %    o image: the image.
1623 %
1624 %    o threshold: Define the threshold value.
1625 %
1626 %    o exception: return any errors or warnings in this structure.
1627 %
1628 */
1629 MagickExport MagickBooleanType WhiteThresholdImage(Image *image,
1630   const char *thresholds,ExceptionInfo *exception)
1631 {
1632 #define ThresholdImageTag  "Threshold/Image"
1633
1634   CacheView
1635     *image_view;
1636
1637   GeometryInfo
1638     geometry_info;
1639
1640   MagickBooleanType
1641     status;
1642
1643   MagickOffsetType
1644     progress;
1645
1646   PixelInfo
1647     threshold;
1648
1649   MagickStatusType
1650     flags;
1651
1652   ssize_t
1653     y;
1654
1655   assert(image != (Image *) NULL);
1656   assert(image->signature == MagickSignature);
1657   if (image->debug != MagickFalse)
1658     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1659   if (thresholds == (const char *) NULL)
1660     return(MagickTrue);
1661   if (SetImageStorageClass(image,DirectClass,exception) == MagickFalse)
1662     return(MagickFalse);
1663   if (IsGrayColorspace(image->colorspace) != MagickFalse)
1664     (void) TransformImageColorspace(image,RGBColorspace,exception);
1665   GetPixelInfo(image,&threshold);
1666   flags=ParseGeometry(thresholds,&geometry_info);
1667   threshold.red=geometry_info.rho;
1668   threshold.green=geometry_info.rho;
1669   threshold.blue=geometry_info.rho;
1670   threshold.black=geometry_info.rho;
1671   threshold.alpha=100.0;
1672   if ((flags & SigmaValue) != 0)
1673     threshold.green=geometry_info.sigma;
1674   if ((flags & XiValue) != 0)
1675     threshold.blue=geometry_info.xi;
1676   if ((flags & PsiValue) != 0)
1677     threshold.alpha=geometry_info.psi;
1678   if (threshold.colorspace == CMYKColorspace)
1679     {
1680       if ((flags & PsiValue) != 0)
1681         threshold.black=geometry_info.psi;
1682       if ((flags & ChiValue) != 0)
1683         threshold.alpha=geometry_info.chi;
1684     }
1685   if ((flags & PercentValue) != 0)
1686     {
1687       threshold.red*=(QuantumRange/100.0);
1688       threshold.green*=(QuantumRange/100.0);
1689       threshold.blue*=(QuantumRange/100.0);
1690       threshold.black*=(QuantumRange/100.0);
1691       threshold.alpha*=(QuantumRange/100.0);
1692     }
1693   /*
1694     White threshold image.
1695   */
1696   status=MagickTrue;
1697   progress=0;
1698   image_view=AcquireAuthenticCacheView(image,exception);
1699 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1700   #pragma omp parallel for schedule(static,4) shared(progress,status) \
1701     dynamic_number_threads(image,image->columns,image->rows,1)
1702 #endif
1703   for (y=0; y < (ssize_t) image->rows; y++)
1704   {
1705     register ssize_t
1706       x;
1707
1708     register Quantum
1709       *restrict q;
1710
1711     if (status == MagickFalse)
1712       continue;
1713     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1714     if (q == (Quantum *) NULL)
1715       {
1716         status=MagickFalse;
1717         continue;
1718       }
1719     for (x=0; x < (ssize_t) image->columns; x++)
1720     {
1721       double
1722         pixel;
1723
1724       register ssize_t
1725         i;
1726
1727       if (GetPixelMask(image,q) != 0)
1728         {
1729           q+=GetPixelChannels(image);
1730           continue;
1731         }
1732       pixel=GetPixelIntensity(image,q);
1733       for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1734       {
1735         PixelChannel
1736           channel;
1737
1738         PixelTrait
1739           traits;
1740
1741         channel=GetPixelChannelChannel(image,i);
1742         traits=GetPixelChannelTraits(image,channel);
1743         if ((traits & UpdatePixelTrait) == 0)
1744           continue;
1745         if (image->channel_mask != DefaultChannels)
1746           pixel=(double) q[i];
1747         if (pixel > GetPixelInfoChannel(&threshold,channel))
1748           q[i]=QuantumRange;
1749       }
1750       q+=GetPixelChannels(image);
1751     }
1752     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1753       status=MagickFalse;
1754     if (image->progress_monitor != (MagickProgressMonitor) NULL)
1755       {
1756         MagickBooleanType
1757           proceed;
1758
1759 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1760         #pragma omp critical (MagickCore_WhiteThresholdImage)
1761 #endif
1762         proceed=SetImageProgress(image,ThresholdImageTag,progress++,
1763           image->rows);
1764         if (proceed == MagickFalse)
1765           status=MagickFalse;
1766       }
1767   }
1768   image_view=DestroyCacheView(image_view);
1769   return(status);
1770 }