/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%               CCCC   OOO   M   M  PPPP    AAA   RRRR    EEEEE               %
%              C      O   O  MM MM  P   P  A   A  R   R   E                   %
%              C      O   O  M M M  PPPP   AAAAA  RRRR    EEE                 %
%              C      O   O  M   M  P      A   A  R R     E                   %
%               CCCC   OOO   M   M  P      A   A  R  R    EEEEE               %
%                                                                             %
%                                                                             %
%                         Image Comparison Methods                            %
%                                                                             %
%                              Software Design                                %
%                                John Cristy                                  %
%                               December 2003                                 %
%                                                                             %
%                                                                             %
%  Copyright 1999-2007 ImageMagick Studio LLC, a non-profit organization      %
%  dedicated to making software imaging solutions freely available.           %
%                                                                             %
%  You may not use this file except in compliance with the License.  You may  %
%  obtain a copy of the License at                                            %
%                                                                             %
%    http://www.imagemagick.org/script/license.php                            %
%                                                                             %
%  Unless required by applicable law or agreed to in writing, software        %
%  distributed under the License is distributed on an "AS IS" BASIS,          %
%  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   %
%  See the License for the specific language governing permissions and        %
%  limitations under the License.                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%
%
*/

/*
  Include declarations.
*/
#include "wand/studio.h"
#include "wand/MagickWand.h"
#include "wand/mogrify-private.h"

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   C o m p a r e I m a g e C o m m a n d                                     %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  CompareImageCommand() compares two images and returns the difference between
%  them as a distortion metric and as a new image visually annotating their
%  differences.
%
%  The format of the CompareImageCommand method is:
%
%      MagickBooleanType CompareImageCommand(ImageInfo *image_info,int argc,
%        char **argv,char **metadata,ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image_info: The image info.
%
%    o argc: The number of elements in the argument vector.
%
%    o argv: A text array containing the command line arguments.
%
%    o metadata: any metadata is returned here.
%
%    o exception: Return any errors or warnings in this structure.
%
*/

static void CompareUsage(void)
{
  const char
    **p;

  static const char
    *settings[]=
    {
      "-alpha option        activate, deactivate, reset, or set the alpha channel",
      "-authenticate value  decrypt image with this password",
      "-channel type        apply option to select image channels",
      "-colorspace type     alternate image colorspace",
      "-compress type       type of pixel compression when writing the image",
      "-debug events        display copious debugging information",
      "-define format:option",
      "                     define one or more image format options",
      "-density geometry    horizontal and vertical density of the image",
      "-depth value         image depth",
      "-extract geometry    extract area from image",
      "-format \"string\"     output formatted image characteristics",
      "-fuzz distance       colors within this distance are considered equal",
      "-help                print program options",
      "-identify            identify the format and characteristics of the image",
      "-interlace type      type of image interlacing scheme",
      "-limit type value    pixel cache resource limit",
      "-log format          format of debugging information",
      "-metric type         measure differences between images with this metric",
      "-monitor             monitor progress",
      "-profile filename    add, delete, or apply an image profile",
      "-quality value       JPEG/MIFF/PNG compression level",
      "-quiet               suppress all warning messages",
      "-quantize colorspace reduce colors in this colorspace",
      "-regard-warnings     pay attention to warning messages",
      "-sampling-factor geometry",
      "                     horizontal and vertical sampling factor",
      "-seed value          seed a new sequence of pseudo-random numbers",
      "-set attribute value set an image attribute",
      "-size geometry       width and height of image",
      "-transparent-color color",
      "                     transparent color",
      "-type type           image type",
      "-verbose             print detailed information about the image",
      "-version             print version information",
      "-virtual-pixel method",
      "                     virtual pixel access method",
      (char *) NULL
    };

  (void) printf("Version: %s\n",GetMagickVersion((unsigned long *) NULL));
  (void) printf("Copyright: %s\n\n",GetMagickCopyright());
  (void) printf("Usage: %s [options ...] image reconstruct difference\n",
    GetClientName());
  (void) printf("\nImage Settings:\n");
  for (p=settings; *p != (char *) NULL; p++)
    (void) printf("  %s\n",*p);
  (void) printf(
    "\nBy default, the image format of `file' is determined by its magic\n");
  (void) printf(
    "number.  To specify a particular image format, precede the filename\n");
  (void) printf(
    "with an image format name and a colon (i.e. ps:image) or specify the\n");
  (void) printf(
    "image type as the filename suffix (i.e. image.ps).  Specify 'file' as\n");
  (void) printf("'-' for standard input or output.\n");
  exit(0);
}

WandExport MagickBooleanType CompareImageCommand(ImageInfo *image_info,
  int argc,char **argv,char **metadata,ExceptionInfo *exception)
{
#define DestroyCompare() \
{ \
  for ( ; k >= 0; k--) \
    image_stack[k]=DestroyImageList(image_stack[k]); \
  for (i=0; i < (long) argc; i++) \
    argv[i]=DestroyString(argv[i]); \
  argv=(char **) RelinquishMagickMemory(argv); \
}
#define ThrowCompareException(asperity,tag,option) \
{ \
  if (exception->severity < (asperity)) \
    (void) ThrowMagickException(exception,GetMagickModule(),asperity,tag, \
      "`%s'",option); \
  DestroyCompare(); \
  return(MagickFalse); \
}
#define ThrowCompareInvalidArgumentException(option,argument) \
{ \
  (void) ThrowMagickException(exception,GetMagickModule(),OptionError, \
    "InvalidArgument","`%s': %s",argument,option); \
  DestroyCompare(); \
  return(MagickFalse); \
}

  char
    *filename,
    *option;

  const char
    *format;

  ChannelType
    channel;

  double
    distortion;

  Image
    *difference_image,
    *image,
    *image_stack[MaxImageStackDepth+1],
    *reconstruct_image;

  long
    j,
    k;

  MagickBooleanType
    fire,
    pend;

  MagickStatusType
    status;

  MetricType
    metric;

  register long
    i;

  /*
    Set defaults.
  */
  assert(image_info != (ImageInfo *) NULL);
  assert(image_info->signature == MagickSignature);
  if (image_info->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
  assert(exception != (ExceptionInfo *) NULL);
  if (argc == 2)
    {
      option=argv[1];
      if ((LocaleCompare("version",option+1) == 0) ||
          (LocaleCompare("-version",option+1) == 0))
        {
          (void) fprintf(stdout,"Version: %s\n",
            GetMagickVersion((unsigned long *) NULL));
          (void) fprintf(stdout,"Copyright: %s\n\n",GetMagickCopyright());
          return(MagickTrue);
        }
    }
  if (argc < 3)
    CompareUsage();
  channel=AllChannels;
  difference_image=NewImageList();
  distortion=0.0;
  format=(char *) NULL;
  j=1;
  k=0;
  image_stack[k]=NewImageList();
  metric=UndefinedMetric;
  option=(char *) NULL;
  pend=MagickFalse;
  reconstruct_image=NewImageList();
  status=MagickTrue;
  /*
    Compare an image.
  */
  ReadCommandlLine(argc,&argv);
  status=ExpandFilenames(&argc,&argv);
  if (status == MagickFalse)
    {
      char
        *message;

      message=GetExceptionMessage(errno);
      ThrowCompareException(ResourceLimitError,"MemoryAllocationFailed",
        message);
      message=DestroyString(message);
    }
  for (i=1; i < (long) (argc-1); i++)
  {
    option=argv[i];
    if (LocaleCompare(option,"(") == 0)
      {
        if (k == MaxImageStackDepth)
          ThrowCompareException(OptionError,"ParenthesisNestedTooDeeply",
            option);
        MogrifyImageStack(image_stack[k],MagickTrue,pend);
        k++;
        image_stack[k]=NewImageList();
        continue;
      }
    if (LocaleCompare(option,")") == 0)
      {
        if (k == 0)
          ThrowCompareException(OptionError,"UnableToParseExpression",option);
        if (image_stack[k] != (Image *) NULL)
          {
            MogrifyImageStack(image_stack[k],MagickTrue,MagickTrue);
            AppendImageToList(&image_stack[k-1],image_stack[k]);
          }
        k--;
        continue;
      }
    if (IsMagickOption(option) == MagickFalse)
      {
        /*
          Read input image.
        */
        MogrifyImageStack(image_stack[k],MagickTrue,pend);
        filename=argv[i];
        if ((LocaleCompare(filename,"--") == 0) && (i < (argc-1)))
          filename=argv[++i];
        (void) CopyMagickString(image_info->filename,filename,MaxTextExtent);
        image=ReadImage(image_info,exception);
        status&=(image != (Image *) NULL) &&
          (exception->severity < ErrorException);
        if (image == (Image *) NULL)
          continue;
        AppendImageToList(&image_stack[k],image);
        continue;
      }
    pend=image_stack[k] != (Image *) NULL ? MagickTrue : MagickFalse;
    switch (*(option+1))
    {
      case 'a':
      {
        if (LocaleCompare("alpha",option+1) == 0)
          {
            long
              type;

            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            type=ParseMagickOption(MagickAlphaOptions,MagickFalse,argv[i]);
            if (type < 0)
              ThrowCompareException(OptionError,"UnrecognizedAlphaChannelType",
                argv[i]);
            break;
          }
        if (LocaleCompare("authenticate",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option);
      }
      case 'c':
      {
        if (LocaleCompare("cache",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (IsGeometry(argv[i]) == MagickFalse)
              ThrowCompareInvalidArgumentException(option,argv[i]);
            break;
          }
        if (LocaleCompare("channel",option+1) == 0)
          {
            long
              channel;

            if (*option == '+')
              break;
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            channel=ParseChannelOption(argv[i]);
            if (channel < 0)
              ThrowCompareException(OptionError,"UnrecognizedChannelType",
                argv[i]);
            break;
          }
        if (LocaleCompare("colorspace",option+1) == 0)
          {
            long
              colorspace;

            if (*option == '+')
              break;
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            colorspace=ParseMagickOption(MagickColorspaceOptions,MagickFalse,
              argv[i]);
            if (colorspace < 0)
              ThrowCompareException(OptionError,"UnrecognizedColorspace",
                argv[i]);
            break;
          }
        if (LocaleCompare("compress",option+1) == 0)
          {
            long
              compress;

            if (*option == '+')
              break;
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            compress=ParseMagickOption(MagickCompressOptions,MagickFalse,
              argv[i]);
            if (compress < 0)
              ThrowCompareException(OptionError,"UnrecognizedImageCompression",
                argv[i]);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'd':
      {
        if (LocaleCompare("debug",option+1) == 0)
          {
            LogEventType
              event_mask;

            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            event_mask=SetLogEventMask(argv[i]);
            if (event_mask == UndefinedEvents)
              ThrowCompareException(OptionError,"UnrecognizedEventType",
                argv[i]);
            break;
          }
        if (LocaleCompare("define",option+1) == 0)
          {
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (*option == '+')
              {
                const char
                  *define;

                define=GetImageOption(image_info,argv[i]);
                if (define == (const char *) NULL)
                  ThrowCompareException(OptionError,"NoSuchOption",argv[i]);
                break;
              }
            break;
          }
        if (LocaleCompare("density",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (IsGeometry(argv[i]) == MagickFalse)
              ThrowCompareInvalidArgumentException(option,argv[i]);
            break;
          }
        if (LocaleCompare("depth",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (IsGeometry(argv[i]) == MagickFalse)
              ThrowCompareInvalidArgumentException(option,argv[i]);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'e':
      {
        if (LocaleCompare("extract",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (IsGeometry(argv[i]) == MagickFalse)
              ThrowCompareInvalidArgumentException(option,argv[i]);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'f':
      {
        if (LocaleCompare("format",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            format=argv[i];
            break;
          }
        if (LocaleCompare("fuzz",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (IsGeometry(argv[i]) == MagickFalse)
              ThrowCompareInvalidArgumentException(option,argv[i]);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'h':
      {
        if ((LocaleCompare("help",option+1) == 0) ||
            (LocaleCompare("-help",option+1) == 0))
          CompareUsage();
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'i':
      {
        if (LocaleCompare("identify",option+1) == 0)
          break;
        if (LocaleCompare("interlace",option+1) == 0)
          {
            long
              interlace;

            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            interlace=ParseMagickOption(MagickInterlaceOptions,MagickFalse,
              argv[i]);
            if (interlace < 0)
              ThrowCompareException(OptionError,"UnrecognizedInterlaceType",
                argv[i]);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'l':
      {
        if (LocaleCompare("limit",option+1) == 0)
          {
            long
              resource;

            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            resource=ParseMagickOption(MagickResourceOptions,MagickFalse,
              argv[i]);
            if (resource < 0)
              ThrowCompareException(OptionError,"UnrecognizedResourceType",
                argv[i]);
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            if ((LocaleCompare("unlimited",argv[i]) != 0) &&
                (IsGeometry(argv[i]) == MagickFalse))
              ThrowCompareInvalidArgumentException(option,argv[i]);
            break;
          }
        if (LocaleCompare("log",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if ((i == (long) argc) || (strchr(argv[i],'%') == (char *) NULL))
              ThrowCompareException(OptionError,"MissingArgument",option);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'm':
      {
        if (LocaleCompare("matte",option+1) == 0)
          break;
        if (LocaleCompare("metric",option+1) == 0)
          {
            long
              type;

            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            type=ParseMagickOption(MagickMetricOptions,MagickTrue,argv[i]);
            if (type < 0)
              ThrowCompareException(OptionError,"UnrecognizedMetricType",
                argv[i]);
            metric=(MetricType) type;
            break;
          }
        if (LocaleCompare("monitor",option+1) == 0)
          break;
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'p':
      {
        if (LocaleCompare("profile",option+1) == 0)
          {
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'q':
      {
        if (LocaleCompare("quality",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (IsGeometry(argv[i]) == MagickFalse)
              ThrowCompareInvalidArgumentException(option,argv[i]);
            break;
          }
        if (LocaleCompare("quantize",option+1) == 0)
          {
            long
              colorspace;

            if (*option == '+')
              break;
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            colorspace=ParseMagickOption(MagickColorspaceOptions,
              MagickFalse,argv[i]);
            if (colorspace < 0)
              ThrowCompareException(OptionError,"UnrecognizedColorspace",
                argv[i]);
            break;
          }
        if (LocaleCompare("quiet",option+1) == 0)
          break;
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'r':
      {
        if (LocaleCompare("regard-warnings",option+1) == 0)
          break;
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 's':
      {
        if (LocaleCompare("sampling-factor",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (IsGeometry(argv[i]) == MagickFalse)
              ThrowCompareInvalidArgumentException(option,argv[i]);
            break;
          }
        if (LocaleCompare("seed",option+1) == 0)
          {
            unsigned long
              seed;

            if (*option == '+')
              {
                seed=(unsigned long) time((time_t *) NULL);
                SeedRandomReservoir(seed);
                break;
              }
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (IsGeometry(argv[i]) == MagickFalse)
              ThrowCompareInvalidArgumentException(option,argv[i]);
            seed=(unsigned long) atol(argv[i]);
            SeedRandomReservoir(seed);
            break;
          }
        if (LocaleCompare("set",option+1) == 0)
          {
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            break;
          }
        if (LocaleCompare("size",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            if (IsGeometry(argv[i]) == MagickFalse)
              ThrowCompareInvalidArgumentException(option,argv[i]);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 't':
      {
        if (LocaleCompare("transparent-color",option+1) == 0)
          {
            if (*option == '+')
              break;
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            break;
          }
        if (LocaleCompare("type",option+1) == 0)
          {
            long
              type;

            if (*option == '+')
              break;
            i++;
            if (i == (long) argc)
              ThrowCompareException(OptionError,"MissingArgument",option);
            type=ParseMagickOption(MagickTypeOptions,MagickFalse,argv[i]);
            if (type < 0)
              ThrowCompareException(OptionError,"UnrecognizedImageType",
                argv[i]);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case 'v':
      {
        if (LocaleCompare("verbose",option+1) == 0)
          break;
        if ((LocaleCompare("version",option+1) == 0) ||
            (LocaleCompare("-version",option+1) == 0))
          {
            (void) fprintf(stdout,"Version: %s\n",
              GetMagickVersion((unsigned long *) NULL));
            (void) fprintf(stdout,"Copyright: %s\n\n",GetMagickCopyright());
            break;
          }
        if (LocaleCompare("virtual-pixel",option+1) == 0)
          {
            long
              method;

            if (*option == '+')
              break;
            i++;
            if (i == (long) (argc-1))
              ThrowCompareException(OptionError,"MissingArgument",option);
            method=ParseMagickOption(MagickVirtualPixelOptions,MagickFalse,
              argv[i]);
            if (method < 0)
              ThrowCompareException(OptionError,
                "UnrecognizedVirtualPixelMethod",argv[i]);
            break;
          }
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
      }
      case '?':
        break;
      default:
        ThrowCompareException(OptionError,"UnrecognizedOption",option)
    }
    fire=(MagickBooleanType) ParseMagickOption(MagickMogrifyOptions,
      MagickFalse,option+1);
    if (fire == MagickTrue)
      MogrifyImageStack(image_stack[k],MagickTrue,MagickTrue);
  }
  if (k != 0)
    ThrowCompareException(OptionError,"UnbalancedParenthesis",argv[i]);
  if (i-- != (long) (argc-1))
    ThrowCompareException(OptionError,"MissingAnImageFilename",argv[i]);
  if ((image_stack[k] == (Image *) NULL) ||
      (GetImageListLength(image_stack[k]) < 2))
    ThrowCompareException(OptionError,"MissingAnImageFilename",argv[i]);
  MogrifyImageStack(image_stack[k],MagickTrue,MagickTrue);
  image=GetImageFromList(image_stack[k],0);
  reconstruct_image=GetImageFromList(image_stack[k],1);
  difference_image=CompareImageChannels(image,reconstruct_image,channel,
    metric,&distortion,exception);
  if (difference_image == (Image *) NULL)
    status=0;
  else
    {
      if (image_info->verbose != MagickFalse)
        (void) IsImagesEqual(image,reconstruct_image);
      status&=WriteImages(image_info,difference_image,argv[argc-1],exception);
      if ((metadata != (char **) NULL) && (format != (char *) NULL))
        {
          char
            *text;

          text=InterpretImageProperties(image_info,difference_image,format);
          if (text == (char *) NULL)
            {
              char
                *message;

              message=GetExceptionMessage(errno);
              ThrowCompareException(ResourceLimitError,"MemoryAllocationFailed",
                message);
              message=DestroyString(message);
            }
          (void) ConcatenateString(&(*metadata),text);
          (void) ConcatenateString(&(*metadata),"\n");
          text=DestroyString(text);
        }
      difference_image=DestroyImageList(difference_image);
      switch (metric)
      {
        case MeanAbsoluteErrorMetric:
        case RootMeanSquaredErrorMetric:
        case PeakAbsoluteErrorMetric:
        {
          (void) fprintf(stderr,"%g (%g)\n",distortion,(double) (QuantumScale*
            distortion));
          break;
        }
        case AbsoluteErrorMetric:
        case MeanSquaredErrorMetric:
        case PeakSignalToNoiseRatioMetric:
        {
          (void) fprintf(stderr,"%g\n",distortion);
          break;
        }
        case MeanErrorPerPixelMetric:
        {
          (void) fprintf(stderr,"%g (%g, %g)\n",distortion,
            image->error.normalized_mean_error,
            image->error.normalized_maximum_error);
          break;
        }
        case UndefinedMetric:
          break;
      }
    }
  DestroyCompare();
  return(status != 0 ? MagickTrue : MagickFalse);
}