C++ GetCacheViewVirtualPixels函数代码示例

/*
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%   G e t I m a g e V i e w I t e r a t o r                                   %
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  GetImageViewIterator() iterates over the image view in parallel and calls
%  your get method for each scanline of the view.  The pixel extent is
%  not confined to the image canvas-- that is you can include negative offsets
%  or widths or heights that exceed the image dimension.  Any updates to
%  the pixels in your callback are ignored.
%
%  The callback signature is:
%
%      MagickBooleanType GetImageViewMethod(const ImageView *source,
%        const ssize_t y,const int thread_id,void *context)
%
%  Use this pragma if the view is not single threaded:
%
%    #pragma omp critical
%
%  to define a section of code in your callback get method that must be
%  executed by a single thread at a time.
%
%  The format of the GetImageViewIterator method is:
%
%      MagickBooleanType GetImageViewIterator(ImageView *source,
%        GetImageViewMethod get,void *context)
%
%  A description of each parameter follows:
%
%    o source: the source image view.
%
%    o get: the get callback method.
%
%    o context: the user defined context.
%
*/
MagickExport MagickBooleanType GetImageViewIterator(ImageView *source,
  GetImageViewMethod get,void *context)
{
  Image
    *source_image;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  ssize_t
    y;

  assert(source != (ImageView *) NULL);
  assert(source->signature == MagickSignature);
  if (get == (GetImageViewMethod) NULL)
    return(MagickFalse);
  source_image=source->image;
  status=MagickTrue;
  progress=0;
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(static,1) shared(progress,status) num_threads(source->number_threads)
#endif
  for (y=source->extent.y; y < (ssize_t) source->extent.height; y++)
  {
    const int
      id = GetOpenMPThreadId();

    register const PixelPacket
      *pixels;

    if (status == MagickFalse)
      continue;
    pixels=GetCacheViewVirtualPixels(source->view,source->extent.x,y,
      source->extent.width,1,source->exception);
    if (pixels == (const PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    if (get(source,y,id,context) == MagickFalse)
      status=MagickFalse;
    if (source_image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_GetImageViewIterator)
#endif
        proceed=SetImageProgress(source_image,source->description,progress++,
          source->extent.height);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
//.........这里部分代码省略.........

/*
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%     I s I m a g e G r a y                                                   %
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%
%  IsImageGray() returns MagickTrue if all the pixels in the image have the
%  same red, green, and blue intensities.
%
%  The format of the IsImageGray method is:
%
%      MagickBooleanType IsImageGray(const Image *image,
%        ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o exception: return any errors or warnings in this structure.
%
*/
MagickExport MagickBooleanType IsImageGray(const Image *image,
  ExceptionInfo *exception)
{
  CacheView
    *image_view;

  ImageType
    type;

  register const Quantum
    *p;

  register ssize_t
    x;

  ssize_t
    y;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if ((image->type == BilevelType) || (image->type == GrayscaleType) ||
      (image->type == GrayscaleMatteType))
    return(MagickTrue);
  if ((IsGrayColorspace(image->colorspace) == MagickFalse) &&
      (IssRGBCompatibleColorspace(image->colorspace) == MagickFalse))
    return(MagickFalse);
  type=BilevelType;
  image_view=AcquireVirtualCacheView(image,exception);
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
    if (p == (const Quantum *) NULL)
      break;
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if (IsPixelGray(image,p) == MagickFalse)
        {
          type=UndefinedType;
          break;
        }
      if ((type == BilevelType) &&
          (IsPixelMonochrome(image,p) == MagickFalse))
        type=GrayscaleType;
      p+=GetPixelChannels(image);
    }
    if (type == UndefinedType)
      break;
  }
  image_view=DestroyCacheView(image_view);
  if (type == UndefinedType)
    return(MagickFalse);
  ((Image *) image)->type=type;
  if ((type == GrayscaleType) && (image->alpha_trait == BlendPixelTrait))
    ((Image *) image)->type=GrayscaleMatteType;
  return(SetImageColorspace((Image *) image,GRAYColorspace,exception));
}

/*
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%     I s G r a y I m a g e                                                   %
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%
%  IsGrayImage() returns MagickTrue if all the pixels in the image have the
%  same red, green, and blue intensities.
%
%  The format of the IsGrayImage method is:
%
%      MagickBooleanType IsGrayImage(const Image *image,
%        ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o exception: return any errors or warnings in this structure.
%
*/
MagickExport MagickBooleanType IsGrayImage(const Image *image,
  ExceptionInfo *exception)
{
  CacheView
    *image_view;

  ImageType
    type;

  long
    y;

  register const PixelPacket
    *p;

  register long
    x;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if ((image->type == BilevelType) || (image->type == GrayscaleType) ||
      (image->type == GrayscaleMatteType))
    return(MagickTrue);
  if (image->colorspace == CMYKColorspace)
    return(MagickFalse);
  type=BilevelType;
  image_view=AcquireCacheView(image);
  for (y=0; y < (long) image->rows; y++)
  {
    p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
    if (p == (const PixelPacket *) NULL)
      break;
    for (x=0; x < (long) image->columns; x++)
    {
      if (IsGrayPixel(p) == MagickFalse)
        {
          type=UndefinedType;
          break;
        }
      if ((type == BilevelType) && (IsMonochromePixel(p) == MagickFalse))
        type=GrayscaleType;
      p++;
    }
    if (type == UndefinedType)
      break;
  }
  image_view=DestroyCacheView(image_view);
  if (type == UndefinedType)
    return(MagickFalse);
  ((Image *) image)->type=type;
  if ((type == GrayscaleType) && (image->matte != MagickFalse))
    ((Image *) image)->type=GrayscaleMatteType;
  return(MagickTrue);
}

MAGICK_NET_EXPORT const Quantum *PixelCollection_GetArea(const CacheView *instance, const size_t x, const size_t y, const size_t width, const size_t height, ExceptionInfo **exception)
{
  const Quantum
    *pixels;

  MAGICK_NET_GET_EXCEPTION;
  pixels = GetCacheViewVirtualPixels(instance, x, y, width, height, exceptionInfo);
  MAGICK_NET_SET_EXCEPTION;
  return pixels;
}

const Magick::PixelPacket* Magick::Pixels::getConst(const ssize_t x_,
  const ssize_t y_,const size_t columns_,const size_t rows_)
{
  _x=x_;
  _y=y_;
  _columns=columns_;
  _rows=rows_;

  GetPPException;
  const PixelPacket* pixels=GetCacheViewVirtualPixels(_view,x_,y_,columns_,
    rows_,exceptionInfo);
  ThrowPPException(_image.quiet());

  return pixels;
}

const Magick::PixelPacket* Magick::Pixels::getConst(const ssize_t x_,
  const ssize_t y_,const size_t columns_,const size_t rows_)
{
  _x=x_;
  _y=y_;
  _columns=columns_;
  _rows=rows_;

  const PixelPacket* pixels=GetCacheViewVirtualPixels(_view,x_,y_,columns_,
    rows_,&_exception);

  if (!pixels)
    throwException(_exception);

  return pixels;
}

/*
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%     I s I m a g e O p a q u e                                               %
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  IsImageOpaque() returns MagickTrue if none of the pixels in the image have
%  an alpha value other than OpaqueAlpha (QuantumRange).
%
%  Will return true immediatally is alpha channel is not available.
%
%  The format of the IsImageOpaque method is:
%
%      MagickBooleanType IsImageOpaque(const Image *image,
%        ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o exception: return any errors or warnings in this structure.
%
*/
MagickExport MagickBooleanType IsImageOpaque(const Image *image,
  ExceptionInfo *exception)
{
  CacheView
    *image_view;

  register const Quantum
    *p;

  register ssize_t
    x;

  ssize_t
    y;

  /*
    Determine if image is opaque.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if (image->alpha_trait != BlendPixelTrait)
    return(MagickTrue);
  image_view=AcquireVirtualCacheView(image,exception);
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
    if (p == (const Quantum *) NULL)
      break;
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if (GetPixelAlpha(image,p) != OpaqueAlpha)
        break;
      p+=GetPixelChannels(image);
    }
    if (x < (ssize_t) image->columns)
     break;
  }
  image_view=DestroyCacheView(image_view);
  return(y < (ssize_t) image->rows ? MagickFalse : MagickTrue);
}

/*
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%     I s O p a q u e I m a g e                                               %
%                                                                             %
%                                                                             %
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  IsOpaqueImage() returns MagickTrue if none of the pixels in the image have
%  an opacity value other than opaque (0).
%
%  The format of the IsOpaqueImage method is:
%
%      MagickBooleanType IsOpaqueImage(const Image *image,
%        ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o exception: return any errors or warnings in this structure.
%
*/
MagickExport MagickBooleanType IsOpaqueImage(const Image *image,
  ExceptionInfo *exception)
{
  CacheView
    *image_view;

  long
    y;

  register const PixelPacket
    *p;

  register long
    x;

  /*
    Determine if image is opaque.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if (image->matte == MagickFalse)
    return(MagickTrue);
  image_view=AcquireCacheView(image);
  for (y=0; y < (long) image->rows; y++)
  {
    p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
    if (p == (const PixelPacket *) NULL)
      break;
    for (x=0; x < (long) image->columns; x++)
    {
      if (p->opacity != OpaqueOpacity)
        break;
      p++;
    }
    if (x < (long) image->columns)
     break;
  }
  image_view=DestroyCacheView(image_view);
  return(y < (long) image->rows ? MagickFalse : MagickTrue);
}

//.........这里部分代码省略.........
    {
      channel_features=(ChannelFeatures *) RelinquishMagickMemory(
        channel_features);
      (void) ThrowMagickException(exception,GetMagickModule(),
        ResourceLimitError,"MemoryAllocationFailed","`%s'",image->filename);
      return(channel_features);
    }
  for (i=0; i <= (ssize_t) MaxMap; i++)
  {
    grays[i].red=(~0U);
    grays[i].green=(~0U);
    grays[i].blue=(~0U);
    grays[i].opacity=(~0U);
    grays[i].index=(~0U);
  }
  status=MagickTrue;
  image_view=AcquireCacheView(image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(static,4) shared(status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register const IndexPacket
      *restrict indexes;

    register const PixelPacket
      *restrict p;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
    if (p == (const PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewVirtualIndexQueue(image_view);
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      grays[ScaleQuantumToMap(GetPixelRed(p))].red=
        ScaleQuantumToMap(GetPixelRed(p));
      grays[ScaleQuantumToMap(GetPixelGreen(p))].green=
        ScaleQuantumToMap(GetPixelGreen(p));
      grays[ScaleQuantumToMap(GetPixelBlue(p))].blue=
        ScaleQuantumToMap(GetPixelBlue(p));
      if (image->colorspace == CMYKColorspace)
        grays[ScaleQuantumToMap(GetPixelIndex(indexes+x))].index=
          ScaleQuantumToMap(GetPixelIndex(indexes+x));
      if (image->matte != MagickFalse)
        grays[ScaleQuantumToMap(GetPixelOpacity(p))].opacity=
          ScaleQuantumToMap(GetPixelOpacity(p));
      p++;
    }
  }
  image_view=DestroyCacheView(image_view);
  if (status == MagickFalse)
    {
      grays=(LongPixelPacket *) RelinquishMagickMemory(grays);
      channel_features=(ChannelFeatures *) RelinquishMagickMemory(
        channel_features);
      return(channel_features);
    }
  (void) ResetMagickMemory(&gray,0,sizeof(gray));

//.........这里部分代码省略.........
    object[i].id=i;
    object[i].bounding_box.x=(ssize_t) image->columns;
    object[i].bounding_box.y=(ssize_t) image->rows;
    GetPixelInfo(image,&object[i].color);
  }
  /*
    Find connected components.
  */
  status=MagickTrue;
  progress=0;
  image_view=AcquireVirtualCacheView(image,exception);
  for (n=0; n < (ssize_t) (connectivity > 4 ? 4 : 2); n++)
  {
    ssize_t
      connect4[2][2] = { { -1,  0 }, {  0, -1 } },
      connect8[4][2] = { { -1, -1 }, { -1,  0 }, { -1,  1 }, {  0, -1 } },
      dx,
      dy;

    if (status == MagickFalse)
      continue;
    dy=connectivity > 4 ? connect8[n][0] : connect4[n][0];
    dx=connectivity > 4 ? connect8[n][1] : connect4[n][1];
    for (y=0; y < (ssize_t) image->rows; y++)
    {
      register const Quantum
        *magick_restrict p;

      register ssize_t
        x;

      if (status == MagickFalse)
        continue;
      p=GetCacheViewVirtualPixels(image_view,0,y-1,image->columns,3,exception);
      if (p == (const Quantum *) NULL)
        {
          status=MagickFalse;
          continue;
        }
      p+=GetPixelChannels(image)*image->columns;
      for (x=0; x < (ssize_t) image->columns; x++)
      {
        PixelInfo
          pixel,
          target;

        ssize_t
          neighbor_offset,
          object,
          offset,
          ox,
          oy,
          root;

        /*
          Is neighbor an authentic pixel and a different color than the pixel?
        */
        GetPixelInfoPixel(image,p,&pixel);
        neighbor_offset=dy*(GetPixelChannels(image)*image->columns)+dx*
          GetPixelChannels(image);
        GetPixelInfoPixel(image,p+neighbor_offset,&target);
        if (((x+dx) < 0) || ((x+dx) >= (ssize_t) image->columns) ||
            ((y+dy) < 0) || ((y+dy) >= (ssize_t) image->rows) ||
            (IsFuzzyEquivalencePixelInfo(&pixel,&target) == MagickFalse))
          {
            p+=GetPixelChannels(image);

static MagickBooleanType InverseFourier(FourierInfo *fourier_info,
  const Image *magnitude_image,const Image *phase_image,fftw_complex *fourier,
  ExceptionInfo *exception)
{
  CacheView
    *magnitude_view,
    *phase_view;

  double
    *magnitude,
    *phase,
    *magnitude_source,
    *phase_source;

  MagickBooleanType
    status;

  register const IndexPacket
    *indexes;

  register const PixelPacket
    *p;

  register ssize_t
    i,
    x;

  ssize_t
    y;

  /*
    Inverse fourier - read image and break down into a double array.
  */
  magnitude_source=(double *) AcquireQuantumMemory((size_t)
    fourier_info->height,fourier_info->width*sizeof(*magnitude_source));
  if (magnitude_source == (double *) NULL)
    {
      (void) ThrowMagickException(exception,GetMagickModule(),
        ResourceLimitError,"MemoryAllocationFailed","`%s'",
        magnitude_image->filename);
      return(MagickFalse);
    }
  phase_source=(double *) AcquireQuantumMemory((size_t) fourier_info->height,
    fourier_info->width*sizeof(*phase_source));
  if (phase_source == (double *) NULL)
    {
      (void) ThrowMagickException(exception,GetMagickModule(),
        ResourceLimitError,"MemoryAllocationFailed","`%s'",
        magnitude_image->filename);
      magnitude_source=(double *) RelinquishMagickMemory(magnitude_source);
      return(MagickFalse);
    }
  i=0L;
  magnitude_view=AcquireVirtualCacheView(magnitude_image,exception);
  for (y=0L; y < (ssize_t) fourier_info->height; y++)
  {
    p=GetCacheViewVirtualPixels(magnitude_view,0L,y,fourier_info->width,1UL,
      exception);
    if (p == (const PixelPacket *) NULL)
      break;
    indexes=GetCacheViewAuthenticIndexQueue(magnitude_view);
    for (x=0L; x < (ssize_t) fourier_info->width; x++)
    {
      switch (fourier_info->channel)
      {
        case RedChannel:
        default:
        {
          magnitude_source[i]=QuantumScale*GetPixelRed(p);
          break;
        }
        case GreenChannel:
        {
          magnitude_source[i]=QuantumScale*GetPixelGreen(p);
          break;
        }
        case BlueChannel:
        {
          magnitude_source[i]=QuantumScale*GetPixelBlue(p);
          break;
        }
        case OpacityChannel:
        {
          magnitude_source[i]=QuantumScale*GetPixelOpacity(p);
          break;
        }
        case IndexChannel:
        {
          magnitude_source[i]=QuantumScale*GetPixelIndex(indexes+x);
          break;
        }
        case GrayChannels:
        {
          magnitude_source[i]=QuantumScale*GetPixelGray(p);
          break;
        }
      }
      i++;
      p++;
    }
//.........这里部分代码省略.........

static MagickBooleanType ForwardFourierTransform(FourierInfo *fourier_info,
  const Image *image,double *magnitude,double *phase,ExceptionInfo *exception)
{
  CacheView
    *image_view;

  double
    n,
    *source;

  fftw_complex
    *fourier;

  fftw_plan
    fftw_r2c_plan;

  register const IndexPacket
    *indexes;

  register const PixelPacket
    *p;

  register ssize_t
    i,
    x;

  ssize_t
    y;

  /*
    Generate the forward Fourier transform.
  */
  source=(double *) AcquireQuantumMemory((size_t) fourier_info->height,
    fourier_info->width*sizeof(*source));
  if (source == (double *) NULL)
    {
      (void) ThrowMagickException(exception,GetMagickModule(),
        ResourceLimitError,"MemoryAllocationFailed","`%s'",image->filename);
      return(MagickFalse);
    }
  ResetMagickMemory(source,0,fourier_info->height*fourier_info->width*
    sizeof(*source));
  i=0L;
  image_view=AcquireVirtualCacheView(image,exception);
  for (y=0L; y < (ssize_t) fourier_info->height; y++)
  {
    p=GetCacheViewVirtualPixels(image_view,0L,y,fourier_info->width,1UL,
      exception);
    if (p == (const PixelPacket *) NULL)
      break;
    indexes=GetCacheViewVirtualIndexQueue(image_view);
    for (x=0L; x < (ssize_t) fourier_info->width; x++)
    {
      switch (fourier_info->channel)
      {
        case RedChannel:
        default:
        {
          source[i]=QuantumScale*GetPixelRed(p);
          break;
        }
        case GreenChannel:
        {
          source[i]=QuantumScale*GetPixelGreen(p);
          break;
        }
        case BlueChannel:
        {
          source[i]=QuantumScale*GetPixelBlue(p);
          break;
        }
        case OpacityChannel:
        {
          source[i]=QuantumScale*GetPixelOpacity(p);
          break;
        }
        case IndexChannel:
        {
          source[i]=QuantumScale*GetPixelIndex(indexes+x);
          break;
        }
        case GrayChannels:
        {
          source[i]=QuantumScale*GetPixelGray(p);
          break;
        }
      }
      i++;
      p++;
    }
  }
  image_view=DestroyCacheView(image_view);
  fourier=(fftw_complex *) AcquireQuantumMemory((size_t) fourier_info->height,
    fourier_info->center*sizeof(*fourier));
  if (fourier == (fftw_complex *) NULL)
    {
      (void) ThrowMagickException(exception,GetMagickModule(),
        ResourceLimitError,"MemoryAllocationFailed","`%s'",image->filename);
      source=(double *) RelinquishMagickMemory(source);
      return(MagickFalse);
//.........这里部分代码省略.........

//.........这里部分代码省略.........
  */
  assert(image != (const Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  assert(exception != (ExceptionInfo *) NULL);
  assert(exception->signature == MagickSignature);
  combine_image=CloneImage(image,0,0,MagickTrue,exception);
  if (combine_image == (Image *) NULL)
    return((Image *) NULL);
  if (SetImageStorageClass(combine_image,DirectClass,exception) == MagickFalse)
    {
      combine_image=DestroyImage(combine_image);
      return((Image *) NULL);
    }
  (void) SetImageColorspace(combine_image,colorspace,exception);
  if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
    combine_image->alpha_trait=BlendPixelTrait;
  /*
    Combine images.
  */
  status=MagickTrue;
  progress=0;
  combine_view=AcquireAuthenticCacheView(combine_image,exception);
  for (y=0; y < (ssize_t) combine_image->rows; y++)
  {
    CacheView
      *image_view;

    const Image
      *next;

    Quantum
      *pixels;

    register const Quantum
      *restrict p;

    register Quantum
      *restrict q;

    register ssize_t
      i;

    if (status == MagickFalse)
      continue;
    pixels=GetCacheViewAuthenticPixels(combine_view,0,y,combine_image->columns,
      1,exception);
    if (pixels == (Quantum *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    next=image;
    for (i=0; i < (ssize_t) GetPixelChannels(combine_image); i++)
    {
      register ssize_t
        x;

      PixelChannel channel=GetPixelChannelChannel(combine_image,i);
      PixelTrait traits=GetPixelChannelTraits(combine_image,channel);
      if (traits == UndefinedPixelTrait)
        continue;
      if (next == (Image *) NULL)
        continue;
      image_view=AcquireVirtualCacheView(next,exception);
      p=GetCacheViewVirtualPixels(image_view,0,y,next->columns,1,exception);
      if (p == (const Quantum *) NULL)
        continue;
      q=pixels;
      for (x=0; x < (ssize_t) combine_image->columns; x++)
      {
        if (x < (ssize_t) next->columns)
          {
            q[i]=GetPixelGray(next,p);
            p+=GetPixelChannels(next);
          }
        q+=GetPixelChannels(combine_image);
      }
      image_view=DestroyCacheView(image_view);
      next=GetNextImageInList(next);
    }
    if (SyncCacheViewAuthenticPixels(combine_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

        proceed=SetImageProgress(image,CombineImageTag,progress++,
          combine_image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  combine_view=DestroyCacheView(combine_view);
  if (status == MagickFalse)
    combine_image=DestroyImage(combine_image);
  return(combine_image);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   S i g n a t u r e I m a g e                                               %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  SignatureImage() computes a message digest from an image pixel stream with
%  an implementation of the NIST SHA-256 Message Digest algorithm.  This
%  signature uniquely identifies the image and is convenient for determining
%  if an image has been modified or whether two images are identical.
%
%  The format of the SignatureImage method is:
%
%      MagickBooleanType SignatureImage(Image *image,ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o exception: return any errors or warnings in this structure.
%
*/
MagickExport MagickBooleanType SignatureImage(Image *image,
  ExceptionInfo *exception)
{
  CacheView
    *image_view;

  char
    *hex_signature;

  double
    pixel;

  register const Quantum
    *p;

  SignatureInfo
    *signature_info;

  ssize_t
    y;

  StringInfo
    *signature;

  unsigned char
    *pixels;

  /*
    Compute image digital signature.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  signature_info=AcquireSignatureInfo();
  signature=AcquireStringInfo(image->columns*GetPixelChannels(image)*
    sizeof(pixel));
  image_view=AcquireVirtualCacheView(image,exception);
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register ssize_t
      x;

    register unsigned char
      *q;

    p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
    if (p == (const Quantum *) NULL)
      break;
    SetStringInfoLength(signature,image->columns*GetPixelChannels(image)*
      sizeof(pixel));
    pixels=GetStringInfoDatum(signature);
    q=pixels;
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      register ssize_t
        i;

      if (GetPixelReadMask(image,p) == 0)
        {
          p+=GetPixelChannels(image);
          continue;
        }
      for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
      {
        register ssize_t
          j;

        PixelChannel channel=GetPixelChannelChannel(image,i);
        PixelTrait traits=GetPixelChannelTraits(image,channel);
        if (traits == UndefinedPixelTrait)
          continue;
        pixel=QuantumScale*p[i];
//.........这里部分代码省略.........

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
+   G e t I m a g e B o u n d i n g B o x                                     %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  GetImageBoundingBox() returns the bounding box of an image canvas.
%
%  The format of the GetImageBoundingBox method is:
%
%      RectangleInfo GetImageBoundingBox(const Image *image,
%        ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o bounds: Method GetImageBoundingBox returns the bounding box of an
%      image canvas.
%
%    o image: the image.
%
%    o exception: return any errors or warnings in this structure.
%
*/
MagickExport RectangleInfo GetImageBoundingBox(const Image *image,
  ExceptionInfo *exception)
{
  CacheView
    *image_view;

  MagickBooleanType
    status;

  PixelInfo
    target[3],
    zero;

  RectangleInfo
    bounds;

  register const Quantum
    *p;

  ssize_t
    y;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  bounds.width=0;
  bounds.height=0;
  bounds.x=(ssize_t) image->columns;
  bounds.y=(ssize_t) image->rows;
  GetPixelInfo(image,&target[0]);
  image_view=AcquireVirtualCacheView(image,exception);
  p=GetCacheViewVirtualPixels(image_view,0,0,1,1,exception);
  if (p == (const Quantum *) NULL)
    {
      image_view=DestroyCacheView(image_view);
      return(bounds);
    }
  GetPixelInfoPixel(image,p,&target[0]);
  GetPixelInfo(image,&target[1]);
  p=GetCacheViewVirtualPixels(image_view,(ssize_t) image->columns-1,0,1,1,
    exception);
  GetPixelInfoPixel(image,p,&target[1]);
  GetPixelInfo(image,&target[2]);
  p=GetCacheViewVirtualPixels(image_view,0,(ssize_t) image->rows-1,1,1,
    exception);
  GetPixelInfoPixel(image,p,&target[2]);
  status=MagickTrue;
  GetPixelInfo(image,&zero);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(static,4) shared(status) \
    magick_threads(image,image,image->rows,1)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    PixelInfo
      pixel;

    RectangleInfo
      bounding_box;

    register const Quantum
      *restrict p;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#  pragma omp critical (MagickCore_GetImageBoundingBox)
#endif
//.........这里部分代码省略.........