coders/mono.c

/*
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%                                                                             %
%                                                                             %
%                                                                             %
%                         M   M   OOO   N   N   OOO                           %
%                         MM MM  O   O  NN  N  O   O                          %
%                         M M M  O   O  N N N  O   O                          %
%                         M   M  O   O  N  NN  O   O                          %
%                         M   M   OOO   N   N   OOO                           %
%                                                                             %
%                                                                             %
%                   Read/Write Raw Bi-Level Bitmap Format                     %
%                                                                             %
%                              Software Design                                %
%                                John Cristy                                  %
%                                 July 1992                                   %
%                                                                             %
%                                                                             %
%  Copyright 1999-2011 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 "MagickCore/studio.h"
#include "MagickCore/blob.h"
#include "MagickCore/blob-private.h"
#include "MagickCore/cache.h"
#include "MagickCore/color-private.h"
#include "MagickCore/colormap.h"
#include "MagickCore/colorspace.h"
#include "MagickCore/colorspace-private.h"
#include "MagickCore/exception.h"
#include "MagickCore/exception-private.h"
#include "MagickCore/image.h"
#include "MagickCore/image-private.h"
#include "MagickCore/list.h"
#include "MagickCore/magick.h"
#include "MagickCore/memory_.h"
#include "MagickCore/monitor.h"
#include "MagickCore/monitor-private.h"
#include "MagickCore/pixel-accessor.h"
#include "MagickCore/quantum-private.h"
#include "MagickCore/static.h"
#include "MagickCore/string_.h"
#include "MagickCore/module.h"

/*
  Forward declarations.
*/
static MagickBooleanType
  WriteMONOImage(const ImageInfo *,Image *,ExceptionInfo *);

/*
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%                                                                             %
%                                                                             %
%   R e a d M O N O I m a g e                                                 %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  ReadMONOImage() reads an image of raw bites in LSB order and returns
%  it.  It allocates the memory necessary for the new Image structure and
%  returns a pointer to the new image.
%
%  The format of the ReadMONOImage method is:
%
%      Image *ReadMONOImage(const ImageInfo *image_info,
%        ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image_info: the image info.
%
%    o exception: return any errors or warnings in this structure.
%
*/
static Image *ReadMONOImage(const ImageInfo *image_info,
  ExceptionInfo *exception)
{
  Image
    *image;

  MagickBooleanType
    status;

  register Quantum
    *q;

  register ssize_t
    x;

  size_t
    bit,
    byte;

  ssize_t
    y;

  /*
    Open image file.
  */
  assert(image_info != (const ImageInfo *) NULL);
  assert(image_info->signature == MagickSignature);
  if (image_info->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
      image_info->filename);
  assert(exception != (ExceptionInfo *) NULL);
  assert(exception->signature == MagickSignature);
  image=AcquireImage(image_info);
  if ((image->columns == 0) || (image->rows == 0))
    ThrowReaderException(OptionError,"MustSpecifyImageSize");
  status=OpenBlob(image_info,image,ReadBinaryBlobMode,exception);
  if (status == MagickFalse)
    {
      image=DestroyImageList(image);
      return((Image *) NULL);
    }
  if (DiscardBlobBytes(image,image->offset) == MagickFalse)
    ThrowFileException(exception,CorruptImageError,"UnexpectedEndOfFile",
      image->filename);
  /*
    Initialize image colormap.
  */
  image->depth=1;
  if (AcquireImageColormap(image,2) == MagickFalse)
    ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed");
  if (image_info->ping != MagickFalse)
    {
      (void) CloseBlob(image);
      return(GetFirstImageInList(image));
    }
  /*
    Convert bi-level image to pixel packets.
  */
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    q=QueueAuthenticPixels(image,0,y,image->columns,1,exception);
    if (q == (const Quantum *) NULL)
      break;
    bit=0;
    byte=0;
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if (bit == 0)
        byte=(size_t) ReadBlobByte(image);
      if (image_info->endian == LSBEndian)
        SetPixelIndex(image,((byte & 0x01) != 0) ? 0x00 : 0x01,q);
      else
        SetPixelIndex(image,((byte & 0x01) != 0) ? 0x01 : 0x00,q);
      bit++;
      if (bit == 8)
        bit=0;
      byte>>=1;
      q+=GetPixelChannels(image);
    }
    if (SyncAuthenticPixels(image,exception) == MagickFalse)
      break;
    status=SetImageProgress(image,LoadImageTag,(MagickOffsetType) y,
      image->rows);
    if (status == MagickFalse)
      break;
  }
  (void) SyncImage(image);
  if (EOFBlob(image) != MagickFalse)
    ThrowFileException(exception,CorruptImageError,"UnexpectedEndOfFile",
      image->filename);
  (void) CloseBlob(image);
  return(GetFirstImageInList(image));
}

/*
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%                                                                             %
%                                                                             %
%                                                                             %
%   R e g i s t e r M O N O I m a g e                                         %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  RegisterMONOImage() adds attributes for the MONO image format to
%  the list of supported formats.  The attributes include the image format
%  tag, a method to read and/or write the format, whether the format
%  supports the saving of more than one frame to the same file or blob,
%  whether the format supports native in-memory I/O, and a brief
%  description of the format.
%
%  The format of the RegisterMONOImage method is:
%
%      size_t RegisterMONOImage(void)
%
*/
ModuleExport size_t RegisterMONOImage(void)
{
  MagickInfo
    *entry;

  entry=SetMagickInfo("MONO");
  entry->decoder=(DecodeImageHandler *) ReadMONOImage;
  entry->encoder=(EncodeImageHandler *) WriteMONOImage;
  entry->raw=MagickTrue;
  entry->endian_support=MagickTrue;
  entry->adjoin=MagickFalse;
  entry->description=ConstantString("Raw bi-level bitmap");
  entry->module=ConstantString("MONO");
  (void) RegisterMagickInfo(entry);
  return(MagickImageCoderSignature);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   U n r e g i s t e r M O N O I m a g e                                     %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  UnregisterMONOImage() removes format registrations made by the
%  MONO module from the list of supported formats.
%
%  The format of the UnregisterMONOImage method is:
%
%      UnregisterMONOImage(void)
%
*/
ModuleExport void UnregisterMONOImage(void)
{
  (void) UnregisterMagickInfo("MONO");
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   W r i t e M O N O I m a g e                                               %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  WriteMONOImage() writes an image of raw bits in LSB order to a file.
%
%  The format of the WriteMONOImage method is:
%
%      MagickBooleanType WriteMONOImage(const ImageInfo *image_info,
%        Image *image,ExceptionInfo *exception)
%
%  A description of each parameter follows.
%
%    o image_info: the image info.
%
%    o image:  The image.
%
%    o exception: return any errors or warnings in this structure.
%
*/
static MagickBooleanType WriteMONOImage(const ImageInfo *image_info,
  Image *image,ExceptionInfo *exception)
{
  MagickBooleanType
    status;

  register const Quantum
    *p;

  register ssize_t
    x;

  size_t
    bit,
    byte;

  ssize_t
    y;

  /*
    Open output image file.
  */
  assert(image_info != (const ImageInfo *) NULL);
  assert(image_info->signature == MagickSignature);
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  status=OpenBlob(image_info,image,WriteBinaryBlobMode,exception);
  if (status == MagickFalse)
    return(status);
  if (IsRGBColorspace(image->colorspace) == MagickFalse)
    (void) TransformImageColorspace(image,RGBColorspace);
  /*
    Convert image to a bi-level image.
  */
  (void) SetImageType(image,BilevelType);
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    p=GetVirtualPixels(image,0,y,image->columns,1,exception);
    if (p == (const Quantum *) NULL)
      break;
    bit=0;
    byte=0;
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      byte>>=1;
      if (image->endian == LSBEndian)
        {
          if (GetPixelIntensity(image,p) < ((Quantum) QuantumRange/2.0))
            byte|=0x80;
        }
      else
        if (GetPixelIntensity(image,p) >= ((Quantum) QuantumRange/2.0))
          byte|=0x80;
      bit++;
      if (bit == 8)
        {
          (void) WriteBlobByte(image,(unsigned char) byte);
          bit=0;
          byte=0;
        }
      p+=GetPixelChannels(image);
    }
    if (bit != 0)
      (void) WriteBlobByte(image,(unsigned char) (byte >> (8-bit)));
    status=SetImageProgress(image,SaveImageTag,(MagickOffsetType) y,
      image->rows);
    if (status == MagickFalse)
      break;
  }
  (void) CloseBlob(image);
  return(MagickTrue);
}