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png.c

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%                            PPPP   N   N   GGGG                              %
%                            P   P  NN  N  G                                  %
%                            PPPP   N N N  G  GG                              %
%                            P      N  NN  G   G                              %
%                            P      N   N   GGG                               %
%                                                                             %
%                                                                             %
%                    Read/Write ImageMagick Image Format.                     %
%                                                                             %
%                                                                             %
%                              Software Design                                %
%                                John Cristy                                  %
%                               November 1997                                 %
%                                                                             %
%                                                                             %
%  Copyright 1997, 1998, 1999 E. I. du Pont de Nemours and Company            %
%                                                                             %
%  Permission is hereby granted, free of charge, to any person obtaining a    %
%  copy of this software and associated documentation files ("ImageMagick"),  %
%  to deal in ImageMagick without restriction, including without limitation   %
%  the rights to use, copy, modify, merge, publish, distribute, sublicense,   %
%  and/or sell copies of ImageMagick, and to permit persons to whom the       %
%  ImageMagick is furnished to do so, subject to the following conditions:    %
%                                                                             %
%  The above copyright notice and this permission notice shall be included in %
%  all copies or substantial portions of ImageMagick.                         %
%                                                                             %
%  The software is provided "as is", without warranty of any kind, express or %
%  implied, including but not limited to the warranties of merchantability,   %
%  fitness for a particular purpose and noninfringement.  In no event shall   %
%  E. I. du Pont de Nemours and Company be liable for any claim, damages or   %
%  other liability, whether in an action of contract, tort or otherwise,      %
%  arising from, out of or in connection with ImageMagick or the use or other %
%  dealings in ImageMagick.                                                   %
%                                                                             %
%  Except as contained in this notice, the name of the E. I. du Pont de       %
%  Nemours and Company shall not be used in advertising or otherwise to       %
%  promote the sale, use or other dealings in ImageMagick without prior       %
%  written authorization from the E. I. du Pont de Nemours and Company.       %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%
*/

/*
  Include declarations.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "magick.h"
#include "defines.h"
#include "config.h"

#if defined(HasPNG)
#include "png.h"
#include "zlib.h"
#include "mng.h"

#undef MNG_OBJECT_BUFFERS

#define MagickVersion "@(#)ImageMagick 4.2.9 99/09/01 cristy@mystic.es.dupont.com"

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   R e a d P N G I m a g e                                                   %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  Method ReadPNGImage reads a Portable Network Graphics (PNG) or
%  Multiple-image Network Graphics (MNG) image file and
%  returns it.  It allocates the memory necessary for the new Image structure
%  and returns a pointer to the new image or set of images.
%
%  MNG support written by Glenn Randers-Pehrson, randeg@alum.rpi.edu
%
%  The format of the ReadPNGImage method is:
%
%      Image *ReadPNGImage(const ImageInfo *image_info)
%
%  A description of each parameter follows:
%
%    o image:  Method ReadPNGImage returns a pointer to the image after
%      reading.  A null image is returned if there is a memory shortage or
%      if the image cannot be read.
%
%    o image_info: Specifies a pointer to an ImageInfo structure.
%
%  To do, more or less in chronological order (as of version 4.2.9,
%
%     August 29, 1999 -- glennrp -- see also "To do" under WritePNGImage):
%
%    (At this point, PNG decoding is supposed to be in full MNG-LC compliance)
%
%    Preserve all unknown and not-yet-handled known chunks found in input
%    PNG file and copy them into output PNG files according to the PNG
%    copying rules.
%
%    (At this point, PNG encoding should be in full MNG compliance)
%
%    Provide options for choice of background to use when the MNG BACK
%    chunk is not present or is not mandatory (i.e., leave transparent,
%    user specified, MNG BACK, PNG bKGD)
%
%    Implement LOOP/ENDL [done, but could do discretionary loops more
%    efficiently by linking in the duplicate frames.].
%
%    Decode JNG datastreams.
%
%    Decode and act on the MHDR simplicity profile (offer option to reject
%    files or attempt to process them anyway when the profile isn't LC or VLC).
%
%    Upgrade to full MNG without Delta-PNG.
%
%        o  BACK [done a while ago except for background image ID]
%        o  MOVE [done 15 May 1999]
%        o  CLIP [done 15 May 1999]
%        o  DISC [done 19 May 1999]
%        o  SAVE [partially done 19 May 1999 (marks objects frozen)]
%        o  SEEK [partially done 19 May 1999 (discard function only)]
%        o  SHOW
%        o  PAST
%        o  BASI
%        o  MNG-level tEXt/zTXt
%        o  pHYg
%        o  pHYs
%        o  sBIT
%        o  bKGD
%        o  iCCP (wait for libpng implementation).
%        o  iTXt (wait for libpng implementation).
%
%    Use the scene signature to discover when an identical scene is
%    being reused, and just point to the original image->pixels instead
%    of storing another set of pixels.  This is not specific to MNG
%    but could be applied generally.
%
%    Upgrade to full MNG with Delta-PNG.
*/

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

#if !defined(PNG_NO_STDIO)
/*
  This is the function that does the actual reading of data.  It is
  the same as the one supplied in libpng, except that it receives the
  datastream from the ReadBlob() function instead of standard input.
*/
static void png_get_data(png_structp png_ptr,png_bytep data,png_size_t length)
{
  Image *
    image=(Image *) png_get_io_ptr(png_ptr);

  /*
    Fread() returns 0 on error, so it is OK to store this in a png_size_t
    instead of an int, which is what fread() actually returns.
  */
  if (length)
    {
      png_size_t
        check;

      check=(png_size_t) ReadBlob(image,(unsigned long) length,(char *)data);
      if (check != length)
        png_error(png_ptr,"Read Error");
    }
}

#ifndef PNG_READ_EMPTY_PLTE_SUPPORTED
/* We use mng_get_data() instead of png_get_data() if we have a libpng
 * older than libpng-1.0.3a, which was the first to allow the empty
 * PLTE, or a newer libpng in which PNG_READ_EMPTY_PLTE_SUPPORTED was
 * ifdef'ed out.  Earlier versions would crash if the bKGD chunk was
 * encountered after an empty PLTE, so we have to look ahead for bKGD
 * chunks and remove them from the datastream that is passed to libpng,
 * and store their contents for later use.
 */
static void mng_get_data(png_structp png_ptr,png_bytep data,png_size_t length)
{
  Mng
    *m;

  Image
    *image;

  png_size_t
    check;

  register int
    i;

  i=0;
  m=(Mng *) png_get_io_ptr(png_ptr);
  image=(Image *) m->image;
  while (m->bytes_in_read_buffer && length)
  {
    data[i]=m->read_buffer[i];
    m->bytes_in_read_buffer--;
    length--;
    i++;
  }
  if (length)
    {
      /*
        fread() returns 0 on error, so it is OK to store this in a png_size_t
        instead of an int, which is what fread() actually returns.
      */
      check=(png_size_t)ReadBlob(image,(unsigned long) length,(char *)data);
      if (check != length)
        png_error(png_ptr,"Read Error");
      if (length == 4)
        {
          if ((data[0] == 0) && (data[1] == 0) && (data[2] == 0) &&
              (data[3] == 0))
            {
              check=(png_size_t)ReadBlob(image,(unsigned long) length,
                (char *) m->read_buffer);
              m->read_buffer[4]=0;
              m->bytes_in_read_buffer=4;
              if (!png_memcmp(m->read_buffer,mng_PLTE, 4))
                m->found_empty_plte=True;
              if (!png_memcmp(m->read_buffer,mng_IEND, 4))
                {
                  m->found_empty_plte=False;
                  m->have_saved_bkgd_index=False;
                }
            }
          if ((data[0] == 0) && (data[1] == 0) && (data[2] == 0) &&
              (data[3] == 1))
            {
              check=(png_size_t)ReadBlob(image,(unsigned long) length,
                (char *) m->read_buffer);
              m->read_buffer[4]=0;
              m->bytes_in_read_buffer=4;
              if (!png_memcmp(m->read_buffer,mng_bKGD,4))
              if (m->found_empty_plte)
                {
                  /*
                    Skip the bKGD data byte and CRC.
                  */
                  check=(png_size_t) ReadBlob(image,5L,(char *) m->read_buffer);
                  check=(png_size_t) ReadBlob(image,(unsigned long) length,
                    (char *) m->read_buffer);
                  m->saved_bkgd_index=m->read_buffer[0];
                  m->have_saved_bkgd_index=True;
                  m->bytes_in_read_buffer=0;
                  if (m->verbose)
                    printf("Read a bKGD chunk after empty PLTE.\n");
                  }
            }
        }
    }
}
#endif

static void png_put_data(png_structp png_ptr,png_bytep data,png_size_t length)
{
  Image
    *image;

  image=(Image *) png_get_io_ptr(png_ptr);
  if (length)
    {
      png_size_t check;
      check = (png_size_t)WriteBlob(image,(unsigned long) length,
          (char *) data);
      if (check != length)
          png_error(png_ptr, "Write Error");
    }
}

static void png_flush_data(png_structp png_ptr)
{
  Image
    *image;

  image=(Image *) png_get_io_ptr(png_ptr);
  FlushBlob(image);
}
#endif

int PalettesAreEqual(const ImageInfo *image_info,Image *a,Image *b)
{
  int
    i;

  if ((a == (Image *) NULL) || (b == (Image *) NULL))
    {
      if (image_info->verbose)
         printf("PalettesAreEqual: image is NULL.\n");
      return((int) False);
    }
  if (!IsPseudoClass(a) || !IsPseudoClass(b))
    {
      if (image_info->verbose)
         printf("PalettesAreEqual: image is not PseudoClass.\n");
      return((int) False);
    }
  if (a->colors != b->colors)
    {
      if (image_info->verbose)
        printf("PalettesAreEqual: a->colors=%d and b->colors=%d\n",
          a->colors,b->colors);
      return((int) False);
    }
  for (i=0; i < (int) a->colors; i++)
  {
    if ((a->colormap[i].red != b->colormap[i].red) ||
        (a->colormap[i].green != b->colormap[i].green) ||
        (a->colormap[i].blue != b->colormap[i].blue))
      {
        if (image_info->verbose)
          printf("PalettesAreEqual: Palettes differ.\n");
        return((int) False);
      }
  }
  return((int)True);
}

static void MngDiscardObject(Mng *m,int i)
{
  if (i && (i < MNG_MAX_OBJECTS) && (m != (Mng *) NULL) && m->exists[i] &&
      !m->frozen[i])
    {
#ifdef MNG_OBJECT_BUFFERS
      if (m->ob[i] != (MngBuffer *)NULL)
        {
          if (m->ob[i]->reference_count > 0)
            m->ob[i]->reference_count--;
          if (m->ob[i]->reference_count == 0)
            {
              if (m->ob[i]->image != (Image *)NULL)
                DestroyImage(m->ob[i]->image);
              if (m->verbose)
                printf("Discarded object buffer[%d]\n",i);
              FreeMemory((char *)m->ob[i]);
            }
        }
      m->ob[i]=(MngBuffer *)NULL;
#endif
      m->exists[i]=False;
      m->visible[i]=True;
      m->viewable[i]=False;
      m->frozen[i]=False;
      m->x_off[i]=0;
      m->y_off[i]=0;
      m->object_clip[i].left=0;
      m->object_clip[i].right=PNG_MAX_UINT;
      m->object_clip[i].top=0;
      m->object_clip[i].bottom=PNG_MAX_UINT;
      if (m->verbose)
        printf("Discarded object %d\n",i);
    }
}

static void MngFreeStruct(Mng *m,int *have_mng_structure)
{
  if (*have_mng_structure && (m != (Mng *) NULL))
    {
      register int
        i;

      if (m->verbose)
        printf("Free mng structure.\n");
      for (i=1; i < MNG_MAX_OBJECTS; i++)
        MngDiscardObject(m,i);
      if (m->global_plte != (png_colorp) NULL)
        FreeMemory(m->global_plte);
      if (m->global_sbit != (png_color_8p) NULL)
        FreeMemory(m->global_sbit);
      FreeMemory((char *) m);
      *have_mng_structure=False;
    }
}

MngBox mng_minimum_box(MngBox box1,MngBox box2)
{
  MngBox
    box;

  box=box1;
  if (box.left < box2.left)
    box.left=box2.left;
  if (box.top < box2.top)
    box.top=box2.top;
  if (box.right > box2.right)
    box.right=box2.right;
  if (box.bottom > box2.bottom)
    box.bottom=box2.bottom;
  return box;
}

MngBox mng_read_box(MngBox previous_box,char delta_type,unsigned char *p)
{
   MngBox
      box;

  /*
    Read clipping boundaries from DEFI, CLIP, FRAM, or PAST chunk.
  */
  box.left=(long) ((p[0]  << 24)| (p[1]  << 16)| (p[2]  << 8) | p[3]);
  box.right=(long) ((p[4]  << 24)| (p[5]  << 16)| (p[6]  << 8) | p[7]);
  box.top=(long) ((p[8]  << 24)| (p[9]  << 16)| (p[10] << 8) | p[11]);
  box.bottom=(long) ((p[12] << 24)| (p[13] << 16)| (p[14] << 8) | p[15]);
  if (delta_type != 0)
    {
      box.left+=previous_box.left;
      box.right+=previous_box.right;
      box.top+=previous_box.top;
      box.bottom+=previous_box.bottom;
    }
  return(box);
}

MngPair mng_read_pair(MngPair previous_pair,char delta_type,unsigned char *p)
{
  MngPair
    pair;

  /*
    Read two longs from MHDR, CLON, MOVE or PAST chunk
  */
  pair.a=(long) ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
  pair.b=(long) ((p[4] << 24) | (p[5] << 16) | (p[6] << 8) | p[7]);
  if (delta_type != 0)
    {
      pair.a+=previous_pair.a;
      pair.b+=previous_pair.b;
    }
  return(pair);
}

long mng_get_long(unsigned char *p)
{
  return((long) ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]));
}

static void MNGCoalesce(Image *image)
{
  long
    delay;

  register Image
    *p;

  if (image->previous == (Image *) NULL)
    return;
  p=image->previous;
  assert(p->next != (Image *) NULL);
  if (p->delay != 0)
    return;
  delay=(long)image->delay;
  CoalesceImages(p);
  p->file=(FILE *) NULL;
  p->orphan=False;
  DestroyImage(p);
  image->delay=delay;
}

static void PNGErrorHandler(png_struct *ping,png_const_charp message)
{
  MagickWarning(DelegateWarning,message,(char *) NULL);
  longjmp(ping->jmpbuf,1);
}

static void ReadTextChunk(png_info *ping_info,unsigned int i,char **value)
{
  unsigned int
    length;

  length=ping_info->text[i].text_length;
  if (*value != (char *) NULL)
    *value=(char *) ReallocateMemory((char *) *value,strlen(*value)+length+1);
  else
    {
      *value=(char *) AllocateMemory(length+1);
      if (*value != (char *) NULL)
        **value='\0';
    }
  if (*value == (char *) NULL)
    {
      MagickWarning(ResourceLimitWarning,"a. Memory allocation failed",
        (char *) NULL);
      return;
    }
  (void) strncat(*value,ping_info->text[i].text,length);
  (*value)[length]='\0';
}

static void PNGWarningHandler(png_struct *ping,png_const_charp message)
{
  MagickWarning(DelegateWarning,message,(char *) NULL);
  if (ping == (png_struct *)NULL)
     return;
}

#ifdef PNG_USER_MEM_SUPPORTED
extern PNG_EXPORT(png_voidp,png_IM_malloc)
  PNGARG((png_structp png_ptr,png_uint_32 size));
extern PNG_EXPORT(png_free_ptr,png_IM_free)
  PNGARG((png_structp png_ptr,png_voidp ptr));
png_voidp png_IM_malloc(png_structp png_ptr,png_uint_32 size)
{
  return((png_voidp) AllocateMemory((size_t)size));
}

/*
  Free a pointer.  It is removed from the list at the same time.
*/
png_free_ptr png_IM_free(png_structp png_ptr,png_voidp ptr)
{
  FreeMemory(ptr);
  return(png_free_ptr) NULL;
}
#endif

#if defined(__cplusplus) || defined(c_plusplus)
}
#endif

Export Image *ReadPNGImage(const ImageInfo *image_info)
{
  char
    page_geometry[MaxTextExtent];

  ColorPacket
    mng_background_color,
    mng_global_bkgd,
    transparent_color;

  Image
    *image;

  int
    have_global_bkgd,
    have_global_chrm,
    have_global_gama,
    have_global_phys,
    have_global_sbit,
    have_global_srgb,
    global_plte_length,
    global_trns_length,
    first_mng_object,
    image_found,
    have_mng_structure,
    object_id,
#if (QuantumDepth == 8)
    reduction_warning,
#endif
    term_chunk_found,
    skip_to_iend,
    y;

  long
    image_count = 0;

  Mng
    *m;

  MngBox
    clip,
    default_fb,
    fb,
    frame,
    image_box,
    previous_fb;

  register int
    i,
    x;

  register long
    packets;

  register unsigned char
    *p;

  register RunlengthPacket
    *q;

  png_info
    *end_info,
    *ping_info;

  png_struct
    *ping;

  short
    loop_level,
    loops_active,
    skipping_loop;

  unsigned char
    *png_pixels,
    **scanlines;

  unsigned int
    framing_mode = 1,
    mandatory_back = 0,
    mng_background_object = 0,
#ifdef MNG_LEVEL
    mng_level,
#endif
    mng_type = 0,   /* 0: PNG; 1: MNG; 2: MNG-LC; 3: MNG-VLC */
    simplicity = 0,
    status;

  unsigned long
    default_frame_delay,
    default_frame_timeout,
    final_delay,
    frame_delay,
    frame_timeout,
    image_height,
    image_width,
    length,
    mng_height = 0,
    mng_width = 0,
    subframe_height,
    subframe_width,
    ticks_per_second;

  unsigned short
    index,
    value;

#ifdef MNG_LEVEL
  mng_level=MNG_LEVEL;
#endif
#if (QuantumDepth == 8)
  reduction_warning=False;
#endif
  /*
    Allocate image structure.
  */
  image=AllocateImage(image_info);
  if (image == (Image *) NULL)
    return((Image *) NULL);
  /*
    Open image file.
  */
  status=OpenBlob(image_info,image,ReadBinaryType);
  if (status == False)
    ReaderExit(FileOpenWarning,"Unable to open file",image);
  first_mng_object=0;
  skipping_loop=(-1);
  have_mng_structure=False;
#ifndef MNG_ALWAYS_VERBOSE
  if (image_info->verbose)
#endif
    printf("Reading %s\n",image_info->filename);
  if (strcmp(image_info->magick,"MNG") == 0)
    {
      char
        magic_number[MaxTextExtent];

      /*
        Verify MNG signature.
      */
      (void) ReadBlob(image,8,magic_number);
      if (strncmp(magic_number,"\212MNG\r\n\032\n",8) != 0)
        ReaderExit(CorruptImageWarning,"Not a MNG image file",image);
#ifndef MNG_ALWAYS_VERBOSE
      if (image_info->verbose)
#endif
        printf("Reading MNG file.\n");
      first_mng_object=1;
      /*
        Allocate a Mng structure.
      */
      m=(Mng *)AllocateMemory(sizeof(Mng));
      if (m == (Mng *) NULL)
        ReaderExit(ResourceLimitWarning,"b. Memory allocation failed", image);
      have_mng_structure=True;
#ifdef MNG_ALWAYS_VERBOSE
      m->verbose = True;
#else
      m->verbose = image_info->verbose;
#endif
      m->image = image;
      m->global_plte=(png_colorp) NULL;
      m->global_sbit=(png_color_8p) NULL;
      m->basi_warning=False;
      m->clon_warning=False;
      m->dhdr_warning=False;
      m->jhdr_warning=False;
      m->past_warning=False;
      m->phyg_warning=False;
      m->phys_warning=False;
      m->sbit_warning=False;
      m->show_warning=False;
      for (i=0; i<MNG_MAX_OBJECTS; i++)
      {
        m->exists[i]=False;
        m->visible[i]=True;
        m->viewable[i]=False;
        m->frozen[i]=False;
        m->x_off[i]=0;
        m->y_off[i]=0;
        m->object_clip[i].left=0;
        m->object_clip[i].right=PNG_MAX_UINT;
        m->object_clip[i].top=0;
        m->object_clip[i].bottom=PNG_MAX_UINT;
#ifdef MNG_OBJECT_BUFFERS
        m->ob[i]=(MngBuffer *)NULL;
#endif
      }
      m->exists[0]=True;
      loop_level=0;
      loops_active=0;
      for (i=0; i < 256; i++)
      {
        m->loop_active[i]=0;
        m->loop_count[i]=0;
        m->loop_iteration[i]=0;
        m->loop_jump[i]=0;
      }
    }
  mng_type=0;
  default_frame_delay=0;
  default_frame_timeout=0;
  frame_delay=0;
  final_delay=100;
  ticks_per_second=100;
  object_id=0;
  skip_to_iend=False;
  term_chunk_found=False;
  image_found=0;
  framing_mode=1;
  mandatory_back=0;
  have_global_chrm=False;
  have_global_bkgd=False;
  have_global_gama=False;
  have_global_phys=False;
  have_global_sbit=False;
  have_global_srgb=False;
  global_plte_length=0;
  global_trns_length=0;
  mng_background_color=image->background_color;
#ifndef MNG_ALWAYS_VERBOSE
  if (image_info->verbose)
#endif
    printf("background color is %3d %3d %3d\n",mng_background_color.red,
      mng_background_color.green, mng_background_color.blue);
  do
  {
    if (strcmp(image_info->magick,"MNG") == 0)
      {
        char
          type[MaxTextExtent];

        unsigned char
          *chunk;

        /*
          Read a new chunk.
        */
        type[0]='\0';
        strcat(type,"errr");
        length=MSBFirstReadLong(image);
        status=ReadBlob(image,4,type);
        if (length > PNG_MAX_UINT)
           status=False;
        if (m->verbose)
          {
            char
              chunk_name[5];

            if (skip_to_iend)
              {
                if (type[0] == 0x4a)   /* 'J' */
                  printf("Skipping JNG ");
                else
                  printf("Skipping PNG ");
              }
            else
              {
                if (!png_memcmp(type, mng_IHDR, 4))
                  printf("PNG ");
                else
                  {
                    if (type[0] == 0x4a)   /* 'J' */
                      printf("Skipping JNG ");
                    else
                      printf("MNG ");
                  }
              }
            for (i=0; i<4; i++)
            {
               const char
                 upper[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
                 lower[] = "abcdefghijklmnopqrstuvwxyz";

               if ((type[i] >= 0x41) && (type[i] <= 0x5A))
                 chunk_name[i]=upper[type[i]-0x41];
               else
                 if ((type[i] >= 0x61) && (type[i] <= 0x7A))
                   chunk_name[i]=lower[type[i]-0x61];
                 else
                   {
                     printf("Invalid byte (0x%x) in chunk name\n",type[i]);
                     chunk_name[i]=0x3f;   /* '?' */
                   }
            }
            chunk_name[4]=0;
            printf("chunk %s, length=%lu\n",chunk_name,length);
          }
        if (status == False)
          {
            MagickWarning(CorruptImageWarning,"Corrupt MNG image",
              image->filename);
            break;
          }

        if (!png_memcmp(type,mng_JHDR,4))
          {
            skip_to_iend=True;
            if (!m->jhdr_warning)
              MagickWarning(DelegateWarning,"JNG is not implemented yet",
                image->filename);
            m->jhdr_warning++;
          }
        if (!png_memcmp(type,mng_DHDR,4))
          {
            skip_to_iend=True;
            if (!m->dhdr_warning)
            MagickWarning(DelegateWarning,"Delta-PNG is not implemented yet",
              image->filename);
            m->dhdr_warning++;
          }
        if (length)
          {
            chunk=(unsigned char *)
              AllocateMemory(length*sizeof(unsigned char));
            if (chunk == (unsigned char *) NULL)
              {
                if (m->verbose)
                  printf("chunk length = %lu\n",length);
                ReaderExit(ResourceLimitWarning,
                 "Unable to allocate memory for chunk data", image);
              }
            for (i=0; i < (int) length; i++)
              chunk[i]=ReadByte(image);
            p=chunk;
          }
        (void) MSBFirstReadLong(image);  /* read crc word */
        if (!png_memcmp(type,mng_MEND,4))
          break;
        if (skip_to_iend)
          {
            if (!png_memcmp(type,mng_IEND,4))
              skip_to_iend=False;
            if (length)
              FreeMemory((char *) chunk);
            continue;
          }

        if (!png_memcmp(type,mng_MHDR,4))
          {
            MngPair
               pair;

            pair.a=0;
            pair.b=0;
            pair=mng_read_pair(pair,0,p);
            mng_width=(unsigned long) pair.a;
            mng_height=(unsigned long) pair.b;
            p+=8;
            ticks_per_second=(unsigned long) mng_get_long(p);
            if (ticks_per_second == 0)
              default_frame_delay=0;
            else
              default_frame_delay=100/ticks_per_second;
            frame_delay=default_frame_delay;
            simplicity=0;
            if (length > 16)
              {
                p+=16;
                simplicity=(unsigned long) mng_get_long(p);
              }
            mng_type=1;    /* Full MNG */
            if ((simplicity != 0) && ((simplicity | 11) == 11))
              mng_type=2; /* LC */
            if ((simplicity != 0) && ((simplicity | 9) == 9))
              mng_type=3; /* VLC */
            if (image->pixels != (RunlengthPacket *) NULL)
              {
                /*
                  Allocate next image structure.
                */
                AllocateNextImage(image_info,image);
                if (image->next == (Image *) NULL)
                  {
                    DestroyImages(image);
                    MngFreeStruct(m,&have_mng_structure);
                    return((Image *) NULL);
                  }
                image=image->next;
              }

            if (mng_width > 65535 || mng_height > 65535)
              MagickWarning(DelegateWarning,"Image dimensions are too large.",
                (char *) NULL);
            FormatString(page_geometry,"%lux%lu%+0+0",mng_width,mng_height);
            frame.left=0;
            frame.right=(long) mng_width;
            frame.top=0;
            frame.bottom=(long) mng_height;
            clip=default_fb=previous_fb=frame;
            for (i=0; i < MNG_MAX_OBJECTS; i++)
              m->object_clip[i]=frame;
            if (m->verbose)
              {
                printf("MHDR data:\n");
                printf("     width=%ld, height=%ld\n",frame.right,frame.bottom);
                printf("     ticks per second=%lu\n",ticks_per_second);
                printf("     simplicity profile=0x%8.8x\n",simplicity);
              }
            FreeMemory((char *) chunk);
            continue;
          }

        if (!png_memcmp(type,mng_TERM,4))
          {
            int
              repeat=0;

            png_uint_32
              iterations;

            if (length > 0)
              repeat=p[0];
            if (repeat == 3)
              {
                final_delay=(int) mng_get_long(&p[2]);
                iterations=(int) mng_get_long(&p[6]);
                if (iterations == PNG_MAX_UINT)
                  iterations=0;
                if (image_info->iterations == (char *) NULL)
                  image->iterations=iterations;
                term_chunk_found = True;
                if (m->verbose)
                  printf("TERM: final_delay=%ld, iterations=%ld\n",
                    final_delay,iterations);
              }
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_DEFI,4))
          {
            if (mng_type == 3)
              MagickWarning(DelegateWarning,
                "DEFI chunk found in MNG-VLC datastream",(char *) NULL);
            object_id = (p[0]<<8) | p[1];
            if (mng_type == 2 && object_id != 0)
              MagickWarning(DelegateWarning,
               "Nonzero object_id in MNG-LC datastream",(char *) NULL);
            if (object_id > MNG_MAX_OBJECTS)
              {
                /*
                  Instead of issuing a warning we should allocate a larger
                  Mng structure and continue.
                */
                MagickWarning(DelegateWarning,"object_id too large",
                  (char *) NULL);
                object_id=MNG_MAX_OBJECTS;
              }
            if (m->exists[object_id])
              if (m->frozen[object_id])
                {
                  MagickWarning(DelegateWarning,
                   "DEFI cannot redefine a frozen MNG object",(char *) NULL);
                  FreeMemory((char *) chunk);
                  continue;
                }
            m->exists[object_id]=True;
            if (length > 2)
              m->visible[object_id]=!p[2];
            /*
              Extract object offset info.
            */
            if (length>11)
              {
                MngPair
                  pair;

                pair.a=0;
                pair.b=0;
                pair=mng_read_pair(pair,0,&p[4]);
                m->x_off[object_id]=pair.a;
                m->y_off[object_id]=pair.b;
              }
            /*
              Extract object clipping info.
            */
            if (length>27)
              m->object_clip[object_id]=mng_read_box(frame,0,&p[12]);
            if (m->verbose)
              {
                printf("  DEFI object_id=%d geometry=%ldx%ld%+ld%+ld\n",
                  object_id, mng_width, mng_height, m->x_off[object_id],
                  m->y_off[object_id]);
                printf("  clipping boundaries: L=%ld R=%ld T=%ld B=%ld\n",
                  m->object_clip[object_id].left,
                  m->object_clip[object_id].right,
                  m->object_clip[object_id].top,
                  m->object_clip[object_id].bottom);
              }
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_bKGD,4))
          {
            have_global_bkgd=False;
            if (length > 5)
              {
                mng_global_bkgd.red=
                  (unsigned short) XDownScale((p[0]<<8) | p[1]);
                mng_global_bkgd.green =
                  (unsigned short) XDownScale((p[2]<<8) | p[3]);
                mng_global_bkgd.blue  =
                  (unsigned short) XDownScale((p[4]<<8) | p[5]);
                have_global_bkgd=True;
              }
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_BACK,4))
          {
            if (length>6)
              mandatory_back=p[6];
            else
              mandatory_back=0;
            if (mandatory_back && length>5)
              {
                mng_background_color.red=
                  (unsigned short) XDownScale((p[0]<<8) | p[1]);
                mng_background_color.green=
                  (unsigned short) XDownScale((p[2]<<8) | p[3]);
                mng_background_color.blue=
                  (unsigned short) XDownScale((p[4]<<8) | p[5]);
              }
            if (length > 8)
              mng_background_object=(p[7] << 8) | p[8];
            if (m->verbose)
              {
                printf(" Background color= %3d %3d %3d, background object=%d",
                  mng_background_color.red,mng_background_color.green,
                  mng_background_color.blue,mng_background_object);
                printf(" (mandatory =%d)\n",mandatory_back);
              }
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_PLTE,4))
          {
            register int
             i;

            /*
              Read global PLTE.
            */
            if (length && (length < 769))
              {
                if (m->global_plte == (png_colorp) NULL)
                  m->global_plte=
                   (png_colorp) AllocateMemory(256*sizeof(png_color));
                for (i=0; i< (int) (length/3); i++)
                {
                  m->global_plte[i].red=p[3*i];
                  m->global_plte[i].green=p[3*i+1];
                  m->global_plte[i].blue=p[3*i+2];
                }
                global_plte_length=(int) length/3;
              }
#ifdef MNG_LOOSE
            for ( ; i < 256; i++)
            {
              m->global_plte[i].red=i;
              m->global_plte[i].green=i;
              m->global_plte[i].blue=i;
            }
            if (length)
              global_plte_length=256;
#endif
            else
              global_plte_length=0;
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_tRNS,4))
          {
            register int
              i;

            /* read global tRNS */

            if (length < 257)
              for (i=0; i<(int) length; i++)
                m->global_trns[i]=p[i];

#ifdef MNG_LOOSE
            for ( ; i<256; i++)
              m->global_trns[i]=255;
#endif
            global_trns_length=(int) length;
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_gAMA,4))
          {
            if (length == 4)
              {
                int igamma=(int) mng_get_long(p);
                m->global_gamma=((float) igamma)*0.00001;
                have_global_gama=True;
              }
            else
              have_global_gama=False;
            FreeMemory((char *) chunk);
            continue;
          }

        if (!png_memcmp(type,mng_cHRM,4))
          {
            /*
              Read global cHRM
            */
            if (length == 32)
              {
                m->global_chrm.white_point.x=.00001*mng_get_long(p);
                m->global_chrm.white_point.y=.00001*mng_get_long(&p[4]);
                m->global_chrm.red_primary.x=.00001*mng_get_long(&p[8]);
                m->global_chrm.red_primary.y=.00001*mng_get_long(&p[12]);
                m->global_chrm.green_primary.x=.00001*mng_get_long(&p[16]);
                m->global_chrm.green_primary.y=.00001*mng_get_long(&p[20]);
                m->global_chrm.blue_primary.x=.00001*mng_get_long(&p[24]);
                m->global_chrm.blue_primary.y=.00001*mng_get_long(&p[28]);
                have_global_chrm=True;
              }
            else
              have_global_chrm=False;
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_sRGB,4))
          {
            /*
              Read global sRGB.
            */
            if (length)
              {
                m->global_srgb_intent=(RenderingIntent) p[0];
                have_global_srgb=True;
              }
            else
              have_global_srgb=False;
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_FRAM,4))
          {
            if (mng_type == 3)
              MagickWarning(DelegateWarning,
                 "FRAM chunk found in MNG-VLC datastream",(char *) NULL);
            if ((framing_mode == 2) || (framing_mode == 4))
              image->delay=frame_delay;
            frame_delay=default_frame_delay;
            frame_timeout=default_frame_timeout;
            fb=default_fb;
            if (length > 0)
              framing_mode=p[0];
            if (length > 6)
              {
                /*
                  Note the delay and frame clipping boundaries.
                */
                p++; /* framing mode */
                while (*p && ((p-chunk) < (int) length))
                  p++;  /* frame name */
                p++;  /* frame name terminator */
                if ((p-chunk) < ((int) length-4))
                  {
                    int
                      change_delay,
                      change_timeout,
                      change_clipping;

                    change_delay=(*p++);
                    change_timeout=(*p++);
                    change_clipping=(*p++);
                    p++; /* change_sync */
                    if (change_delay)
                      {
                        frame_delay=(unsigned int)
                          (100*(mng_get_long(p))/ticks_per_second);
                        if (change_delay == 2)
                          default_frame_delay=frame_delay;
                        p+=4;
                      }
                    if (change_timeout)
                      {
                        frame_timeout=(unsigned int)
                          (100*(mng_get_long(p))/ticks_per_second);
                        if (change_delay == 2)
                          default_frame_timeout=frame_timeout;
                        p+=4;
                      }
                    if (change_clipping)
                      {
                        fb=mng_read_box(previous_fb,p[0],&p[1]);
                        p+=17;
                        previous_fb=fb;
                      }
                    if (change_clipping == 2)
                      default_fb=fb;
                  }
              }
            clip=fb;
            clip=mng_minimum_box(fb,frame);
            subframe_width=(unsigned int) (clip.right-clip.left);
            subframe_height=(unsigned int) (clip.bottom-clip.top);
            /*
              Insert a background layer behind the frame if framing_mode is 4.
            */
            if (image_info->insert_backdrops && (framing_mode == 4) &&
                (subframe_width > 0) && (subframe_height > 0))
              {
                char
                  background_page_geometry[MaxTextExtent];

                /*
                  Allocate next image structure.
                */
                AllocateNextImage(image_info,image);
                if (image->next == (Image *) NULL)
                  {
                    DestroyImages(image);
                    MngFreeStruct(m,&have_mng_structure);
                    return((Image *) NULL);
                  }
                image=image->next;
                if (term_chunk_found)
                  {
                    image->restart_animation_here=True;
                    term_chunk_found=False;
                    if (m->verbose)
                      printf("Setting restart_animation_here\n");
                  }
                image->columns=subframe_width;
                image->rows=subframe_height;
                FormatString(background_page_geometry,"%lux%lu%+ld%+ld",
                  subframe_width,subframe_height,clip.left,clip.top);
                if (image->page != (char *) NULL)
                  FreeMemory((char *) image->page);
                image->page=PostscriptGeometry(background_page_geometry);
                image->packets=image->columns*image->rows;
                image->pixels=(RunlengthPacket *)
                    AllocateMemory(image->packets*sizeof(RunlengthPacket));
                if (image->pixels == (RunlengthPacket *) NULL)
                  {
                    MagickWarning(ResourceLimitWarning,
                      "Memory allocation failed",(char *) NULL);
                    MngFreeStruct(m,&have_mng_structure);
                    return((Image *) NULL);
                  }
                image->background_color=mng_background_color;
                image->matte=False;
                SetImage(image);
                image->delay=0;
                if (image_info->coalesce_frames)
                  MNGCoalesce(image);
              }
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_CLIP,4))
          {
            unsigned int
              first_object,
              last_object;

            /*
              Read CLIP.
            */
            first_object=(p[0]<<8) | p[1];
            last_object=(p[2]<<8) | p[3];
            if (m->verbose)
              printf("CLIP: first_object=%u, last_object=%u\n",
                first_object,last_object);
            for (i=(int) first_object; i<=(int) last_object; i++)
            {
              if (m->exists[i] && !m->frozen[i])
                {
                  MngBox
                    box;

                  box=m->object_clip[i];
                  m->object_clip[i]=mng_read_box(box,p[4],&p[5]);
                  if (m->verbose)
                    printf("  new clip[%d]: L=%ld, R=%ld, T=%ld, B=%ld\n",
                       i,m->object_clip[i].left,m->object_clip[i].right,
                       m->object_clip[i].top,m->object_clip[i].bottom);
                }
            }
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_SAVE,4))
          {
            register int
              i;

            for (i=1; i<MNG_MAX_OBJECTS; i++)
              if (m->exists[i])
                {
                 m->frozen[i]=True;
#ifdef MNG_OBJECT_BUFFERS
                 if (m->ob[i] != (MngBuffer *)NULL)
                    m->ob[i]->frozen=True;
#endif
                }
            if (length > 0)
              FreeMemory((char *) chunk);
            continue;
          }

        if (!png_memcmp(type,mng_DISC,4) || !png_memcmp(type,mng_SEEK,4))
          {
            register int
              i;

            /*
              Read DISC or SEEK.
            */
            if ((length == 0) || !png_memcmp(type,mng_SEEK,4))
              {
                for (i=1; i < MNG_MAX_OBJECTS; i++)
                  MngDiscardObject(m,i);
              }
            else
              {
                register int
                  j;

                for (j=0; j<(int) length; j+=2)
                {
                  i=p[j]<<8 | p[j+1];
                  MngDiscardObject(m,i);
                }
              }
            if (length > 0)
              FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_MOVE,4))
          {
            long
              first_object,
              last_object;

            /*
              read MOVE
            */
            first_object=(p[0]<<8) | p[1];
            last_object=(p[2]<<8) | p[3];
            for (i=first_object; i <= last_object; i++)
            {
              if (m->exists[i] && !m->frozen[i])
                {
                  MngPair
                    new_pair,
                    old_pair;

                  old_pair.a=m->x_off[i];
                  old_pair.b=m->y_off[i];
                  new_pair=mng_read_pair(old_pair,p[4],&p[5]);
                  m->x_off[i]=new_pair.a;
                  m->y_off[i]=new_pair.b;
                  if (m->verbose)
                    printf("  MOVE to x[%d]=%ld, y[%d]=%ld\n",
                       i,m->x_off[i],i,m->y_off[i]);
                }
            }
            FreeMemory((char *) chunk);
            continue;
          }

        if (!png_memcmp(type,mng_LOOP,4))
          {
            long loop_iters=1;
            loop_level=chunk[0];
            loops_active++;
            m->loop_active[loop_level]=1;  /* mark loop active */
            /*
              Record starting point.
            */
            loop_iters = mng_get_long(&chunk[1]);
            if (loop_iters == 0)
              skipping_loop=loop_level;
            else
              {
                m->loop_jump[loop_level]=TellBlob(image);
                m->loop_count[loop_level]=loop_iters;
              }
            if (m->verbose)
              {
                printf("loop offset=%ld, ",m->loop_jump[loop_level]);
                printf("loop iterations=%ld\n",m->loop_count[loop_level]);
              }
            m->loop_iteration[loop_level]=0;
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_ENDL,4))
          {
            loop_level=chunk[0];
            if (skipping_loop > 0)
              {
                if (skipping_loop == loop_level)
                  {
                    /*
                      Found end of zero-iteration loop.
                    */
                    skipping_loop=(-1);
                    loops_active--;
                    m->loop_active[loop_level]=0;
                  }
              }
            else
              {
                if (m->loop_active[loop_level] == 1)
                  {
                    if (m->verbose)
                      printf("Processing ENDL chunk.\n");
                    m->loop_count[loop_level]--;
                    m->loop_iteration[loop_level]++;
                    if (m->loop_count[loop_level] == 0)
                      {
                        int
                          last_level;

                        /*
                          Finished loop.
                        */
                        loops_active--;
                        m->loop_active[loop_level]=0;
                        last_level=(-1);
                        for (i=0; i < loop_level; i++)
                          if (m->loop_active[i] == 1)
                            last_level=i;
                        loop_level=last_level;
                      }
                    else
                      {
                        /*
                          Jump back for another iteration of loop.
                        */
                        if (m->verbose != 0)
                          printf("LOOP back to %ld for another iteration\n",
                            m->loop_jump[loop_level]);
                        SeekBlob(image, m->loop_jump[loop_level], SEEK_SET);
                      }
                  }
              }
            FreeMemory((char *) chunk);
            continue;
          }
        if (!png_memcmp(type,mng_CLON,4))
          {
            if (!m->clon_warning)
              MagickWarning(DelegateWarning,"CLON is not implemented yet",
                image->filename);
            m->clon_warning++;
          }
        if (!png_memcmp(type,mng_PAST,4))
          {
            if (!m->past_warning)
              MagickWarning(DelegateWarning,"PAST is not implemented yet",
                image->filename);
            m->past_warning++;
          }
        if (!png_memcmp(type,mng_SHOW,4))
          {
            if (!m->show_warning)
              MagickWarning(DelegateWarning,"SHOW is not implemented yet",
                image->filename);
            m->show_warning++;
          }
        if (!png_memcmp(type,mng_sBIT,4))
          {
            if (length < 4)
              have_global_sbit=False;
            else
              {
                if (m->global_sbit == (png_color_8p) NULL)
                  m->global_sbit=
                    (png_color_8p) AllocateMemory(sizeof(png_color_8));
                m->global_sbit->gray=p[0];
                m->global_sbit->red=p[0];
                m->global_sbit->green=p[1];
                m->global_sbit->blue=p[2];
                m->global_sbit->alpha=p[3];
                have_global_sbit=True;
             }
          }
        if (!png_memcmp(type, mng_pHYs, 4))
          {
            if (length > 8)
              {
                m->global_x_pixels_per_unit=mng_get_long(p);
                m->global_y_pixels_per_unit=mng_get_long(&p[4]);
                m->global_phys_unit_type=p[8];
                have_global_phys=True;
              }
            else
              have_global_phys=False;
          }
        if (!png_memcmp(type,mng_pHYg,4))
          {
            if (!m->phyg_warning)
              MagickWarning(DelegateWarning,"pHYg is not implemented.",
                image->filename);
            m->phyg_warning++;
          }
        if (!png_memcmp(type,mng_BASI,4))
          {
#ifdef MNG_BASI_SUPPORTED
            MngPair
               pair;
#endif
            skip_to_iend=True;
            if (!m->basi_warning)
              MagickWarning(DelegateWarning,"BASI is not implemented yet",
                image->filename);
            m->basi_warning++;
#ifdef MNG_BASI_SUPPORTED
            pair.a=0;
            pair.b=0;
            pair=mng_read_pair(pair,0,p);
            basi_width=(unsigned long)pair.a;
            basi_height=(unsigned long)pair.b;
            basi_color_type=p[8];
            basi_compression_method=p[9];
            basi_filter_type=p[10];
            basi_interlace_method=p[11];
            if (length > 11)
              basi_red=(p[12] << 8) & p[13];
            else
              basi_red=0;
            if (length > 13)
              basi_green=(p[14] << 8) & p[15];
            else
              basi_green=0;
            if (length > 15)
              basi_blue=(p[16] << 8) & p[17];
            else
              basi_blue=0;
            if (length > 17)
              basi_alpha=(p[18] << 8) & p[19];
            else
              {
                if (basi_sample_depth == 16)
                  basi_alpha=65535;
                else
                  basi_alpha=255;
              }
            if (length > 19)
              basi_viewable=p[20];
            else
              basi_viewable=0;
#endif
            FreeMemory((char *) chunk);
            continue;
          }
        if (png_memcmp(type,mng_IHDR,4))
          {
            if (length > 0)
              FreeMemory((char *) chunk);
            continue;
          }
        m->exists[object_id]=True;
        m->viewable[object_id]=True;
        if (!m->visible[object_id])
          {
            if (!image_info->decode_all_MNG_objects)
              {
                if (m->verbose)
                  printf("skipping invisible object %d...\n",object_id);
                skip_to_iend=True;
                FreeMemory((char *) chunk);
                continue;
              }
          }
        if (m->verbose)
          printf("  object_id=%d geometry=%ldx%ld%+ld%+ld\n",
            object_id, mng_width, mng_height, m->x_off[object_id],
            m->y_off[object_id]);
        /*
          Insert a background layer behind the upcoming image if
          framing_mode is 3 and transparency might be present.
        */
        image_width=(unsigned int) mng_get_long(p);
        image_height=(unsigned int) mng_get_long(&p[4]);
        FreeMemory((char *) chunk);
        if (image_info->insert_backdrops && (framing_mode == 3) &&
            ((first_mng_object == 0) || ((clip.left == 0) && (clip.top == 0) &&
              (image_width == mng_width) && (image_height == mng_height))))
          {
            if (simplicity == 0 || (simplicity & 0x08) == 0x08)
              {
                char
                  background_page_geometry[MaxTextExtent];

                int
                  delay;

                /*
                  Allocate next image structure.
                */
                AllocateNextImage(image_info,image);
                if (image->next == (Image *) NULL)
                  {
                    DestroyImages(image);
                    MngFreeStruct(m,&have_mng_structure);
                    return((Image *) NULL);
                  }
                image=image->next;
                if (term_chunk_found)
                  {
                    image->restart_animation_here = True;
                    term_chunk_found=False;
                    if (m->verbose)
                      printf("Setting restart_animation_here\n");
                  }

                delay=image->delay;
                image->delay=0;
                image->columns=subframe_width;
                image->rows=subframe_height;
                FormatString(background_page_geometry,"%lux%lu%+ld%+ld",
                  subframe_width, subframe_height, clip.left, clip.top);
                if (image->page != (char *) NULL)
                  FreeMemory((char *) image->page);
                image->page=PostscriptGeometry(background_page_geometry);
                image->packets=image->columns*image->rows;
                image->pixels=(RunlengthPacket *)
                  AllocateMemory(image->packets*sizeof(RunlengthPacket));
                if (image->pixels == (RunlengthPacket *) NULL)
                  {
                    MagickWarning(ResourceLimitWarning,
                      "e. Memory allocation failed", (char *) NULL);
                    MngFreeStruct(m,&have_mng_structure);
                    return((Image *) NULL);
                  }
                image->background_color = mng_background_color;
                image->matte = False;
                SetImage(image);
                image->delay = delay;
                if (image_info->verbose)
                   printf("inserted a layer with color %5d %5d %5d\n",
                      image->background_color.red,
                      image->background_color.green,
                      image->background_color.blue);
              }
          }
        /*
          Insert a background layer behind the entire animation if it
          is not full screen or transparency might be present.
        */
        if (mng_type && image_info->insert_backdrops && first_mng_object)
          {
            if ((simplicity == 0) || ((simplicity & 0x08) == 0x08) ||
                ((clip.left != 0) || (clip.top != 0) ||
                (image_width != mng_width) || (image_height != mng_height)))
              {
                int
                  delay;

                char
                  background_page_geometry[MaxTextExtent];

                /*
                  Make a background rectangle.
                */
                delay=image->delay;
                image->delay=0;
                image->columns=mng_width;
                image->rows=mng_height;
                FormatString(background_page_geometry,"%lux%lu%+ld%+ld",
                  mng_width, mng_height, 0, 0);
                if (image->page != (char *) NULL)
                  FreeMemory((char *) image->page);
                image->page=PostscriptGeometry(background_page_geometry);
                image->packets=image->columns*image->rows;
                image->pixels=(RunlengthPacket *)
                  AllocateMemory(image->packets*sizeof(RunlengthPacket));
                if (image->pixels == (RunlengthPacket *) NULL)
                  {
                    MagickWarning(ResourceLimitWarning,
                     "Memory allocation failed", (char *) NULL);
                    MngFreeStruct(m,&have_mng_structure);
                    return((Image *) NULL);
                  }
                image->background_color=mng_background_color;
                image->matte=False;
                image->delay=delay;
                SetImage(image);
              }
          }
        first_mng_object=0;
        /*
          Read the PNG image.
        */
        if (image->pixels != (RunlengthPacket *) NULL)
          {
            /*
              Allocate next image structure.
            */
            AllocateNextImage(image_info,image);
            if (image->next == (Image *) NULL)
              {
                DestroyImages(image);
                MngFreeStruct(m,&have_mng_structure);
                return((Image *) NULL);
              }
            image=image->next;
          }
        if (term_chunk_found)
          {
            image->restart_animation_here = True;
            term_chunk_found=False;
            if (m->verbose)
              printf("Setting restart_animation_here\n");
          }
        if (framing_mode == 1 || framing_mode == 3)
          {
            image->delay=frame_delay;
            frame_delay = default_frame_delay;
          }
        else
          image->delay=0;
        FormatString(page_geometry,"%lux%lu%+ld%+ld",mng_width,
          mng_height,m->x_off[object_id], m->y_off[object_id]);
        if (image->page != (char *) NULL)
          FreeMemory((char *) image->page);
        image->page=PostscriptGeometry(page_geometry);
        /*
          Seek back to the beginning of the IHDR chunk's length field.
        */
        (void) SeekBlob(image,-((int) length+12),SEEK_CUR);
      }

    /*
      Allocate the PNG structures
    */
#ifdef PNG_USER_MEM_SUPPORTED
   ping=png_create_read_struct_2(PNG_LIBPNG_VER_STRING, (void *) NULL,
     PNGErrorHandler,PNGWarningHandler, (void *) NULL,
     (png_malloc_ptr) png_IM_malloc, (png_free_ptr) png_IM_free);
#else
    ping=png_create_read_struct(PNG_LIBPNG_VER_STRING,(void *) NULL,
      PNGErrorHandler,PNGWarningHandler);
#endif
    if (ping == (png_struct *) NULL)
      ReaderExit(ResourceLimitWarning,"g. Memory allocation failed",image);
    ping_info=png_create_info_struct(ping);
    if (ping_info == (png_info *) NULL)
      {
        png_destroy_read_struct(&ping,(png_info **) NULL,(png_info **) NULL);
        ReaderExit(ResourceLimitWarning,"h. Memory allocation failed",image);
      }
    end_info=png_create_info_struct(ping);
    if (end_info == (png_info *) NULL)
      {
        png_destroy_read_struct(&ping,&ping_info,(png_info **) NULL);
        ReaderExit(ResourceLimitWarning,"i. Memory allocation failed",image);
      }
    image->pixels=(RunlengthPacket *) NULL;
    png_pixels=(unsigned char *) NULL;
    scanlines=(unsigned char **) NULL;
    if (setjmp(ping->jmpbuf))
      {
        /*
          PNG image is corrupt.
        */
        png_destroy_read_struct(&ping,&ping_info,&end_info);
        if (scanlines != (unsigned char **) NULL)
          FreeMemory((char *) scanlines);
        if (png_pixels != (unsigned char *) NULL)
          FreeMemory((char *) png_pixels);
        CloseBlob(image);
        if ((image->columns == 0) || (image->rows == 0))
          {
            DestroyImage(image);
            MngFreeStruct(m,&have_mng_structure);
            return((Image *) NULL);
          }
        MngFreeStruct(m,&have_mng_structure);
        return(image);
      }
    /*
      Prepare PNG for reading.
    */
    image_found++;
    if (strcmp(image_info->magick,"MNG") == 0)
      {
        png_set_sig_bytes(ping,8);
#ifdef PNG_READ_EMPTY_PLTE_SUPPORTED
        png_permit_empty_plte(ping,True);
        png_set_read_fn(ping,image,png_get_data);
#else
        png_set_read_fn(ping,m,mng_get_data);
        m->bytes_in_read_buffer=0;
        m->found_empty_plte=False;
        m->have_saved_bkgd_index=False;
#endif
      }
    else
      png_set_read_fn(ping,image,png_get_data);
    png_read_info(ping,ping_info);
    image->depth=ping_info->bit_depth;
    if (ping_info->bit_depth < 8)
      {
        if ((ping_info->color_type == PNG_COLOR_TYPE_PALETTE) ||
            (ping_info->color_type == PNG_COLOR_TYPE_GRAY))
          png_set_packing(ping);
        image->depth=8;
      }
#if defined(PNG_READ_sRGB_SUPPORTED)
    if (have_global_srgb)
      image->rendering_intent=(RenderingIntent) (m->global_srgb_intent+1);
    if (ping_info->valid & PNG_INFO_sRGB)
      image->rendering_intent=(RenderingIntent) (ping_info->srgb_intent+1);
#endif
    if (have_global_gama)
      image->gamma=m->global_gamma;
    if (ping_info->valid & PNG_INFO_gAMA)
      image->gamma=ping_info->gamma;
    if (have_global_chrm)
        image->chromaticity=m->global_chrm;
    if (ping_info->valid & PNG_INFO_cHRM)
      {
        image->chromaticity.white_point.x=ping_info->x_white;
        image->chromaticity.white_point.y=ping_info->y_white;
        image->chromaticity.red_primary.x=ping_info->x_red;
        image->chromaticity.red_primary.y=ping_info->y_red;
        image->chromaticity.green_primary.x=ping_info->x_green;
        image->chromaticity.green_primary.y=ping_info->y_green;
        image->chromaticity.blue_primary.x=ping_info->x_blue;
        image->chromaticity.blue_primary.y=ping_info->y_blue;
      }
    if (image->rendering_intent)
      {
        image->gamma=.45455;
        image->chromaticity.white_point.x  =0.3127;
        image->chromaticity.white_point.y  =0.3290;
        image->chromaticity.red_primary.x  =0.6400;
        image->chromaticity.red_primary.y  =0.3300;
        image->chromaticity.green_primary.x=0.3000;
        image->chromaticity.green_primary.y=0.6000;
        image->chromaticity.blue_primary.x =0.1500;
        image->chromaticity.blue_primary.y =0.0600;
      }
    if (have_global_gama || image->rendering_intent)
      ping_info->valid |= PNG_INFO_gAMA;
    if (have_global_chrm || image->rendering_intent)
      ping_info->valid |= PNG_INFO_cHRM;
    if (ping_info->valid & PNG_INFO_pHYs)
      {
        /*
          Set image resolution.
        */
        image->x_resolution=(float)ping_info->x_pixels_per_unit;
        image->y_resolution=(float)ping_info->y_pixels_per_unit;
        if (ping_info->phys_unit_type == PNG_RESOLUTION_METER)
          {
            image->units=PixelsPerCentimeterResolution;
            image->x_resolution=(float)ping_info->x_pixels_per_unit/100.0;
            image->y_resolution=(float)ping_info->y_pixels_per_unit/100.0;
          }
      }
    else
      {
        if (have_global_phys)
          {
            image->x_resolution=(float)m->global_x_pixels_per_unit;
            image->y_resolution=(float)m->global_y_pixels_per_unit;
            if (m->global_phys_unit_type == PNG_RESOLUTION_METER)
              {
                image->units=PixelsPerCentimeterResolution;
                image->x_resolution=(float) m->global_x_pixels_per_unit/100.0;
                image->y_resolution=(float) m->global_y_pixels_per_unit/100.0;
              }
            ping_info->valid |= PNG_INFO_pHYs;
          }
      }

    if (ping_info->valid & PNG_INFO_PLTE)
      {
        int
          num_palette;

        png_colorp
          palette;

        png_get_PLTE(ping,ping_info,&palette,&num_palette);
        if (num_palette == 0 && ping_info->color_type == PNG_COLOR_TYPE_PALETTE)
          {
            if (global_plte_length)
              {
                png_set_PLTE(ping,ping_info,m->global_plte,global_plte_length);
                if (m->verbose)
                  printf("setting global PLTE.\n");
                if (!(ping_info->valid & PNG_INFO_tRNS))
                  if (global_trns_length)
                    {
                      if (m->verbose)
                        printf("setting global tRNS.\n");
                      if (global_trns_length > global_plte_length)
                        MagickWarning(DelegateWarning,
                          "global tRNS has more entries than global PLTE",
                          image_info->filename);
                      png_set_tRNS(ping,ping_info,m->global_trns,
                        global_trns_length,NULL);
                    }
#if defined(PNG_READ_bKGD_SUPPORTED)
                if (
#ifndef PNG_READ_EMPTY_PLTE_SUPPORTED
                     m->have_saved_bkgd_index ||
#endif
                     ping_info->valid & PNG_INFO_bKGD)
                  {
                    png_color_16
                       background;

#ifndef PNG_READ_EMPTY_PLTE_SUPPORTED
                    if (m->have_saved_bkgd_index)
                      background.index=m->saved_bkgd_index;
                    else
#endif
                      background.index=ping_info->background.index;
                    background.red=
                       (png_uint_16) m->global_plte[background.index].red;
                    background.green=
                       (png_uint_16) m->global_plte[background.index].green;
                    background.blue =
                       (png_uint_16) m->global_plte[background.index].blue;
                    png_set_bKGD(ping,ping_info,&background);
                  }
#endif
              }
            else
              MagickWarning(DelegateWarning,
                "No global PLTE in file",image_info->filename);
          }
      }

#if defined(PNG_READ_bKGD_SUPPORTED)
    if (have_global_bkgd && !(ping_info->valid & PNG_INFO_bKGD))
      {
#if (QuantumDepth == 16)
        image->background_color=mng_global_bkgd;
#else
        image->background_color.red=
          (unsigned short)XDownScale(mng_global_bkgd.red);
        image->background_color.green=
          (unsigned short)XDownScale(mng_global_bkgd.green);
        image->background_color.blue=
          (unsigned short)XDownScale(mng_global_bkgd.blue);
#endif
      }
    if (ping_info->valid & PNG_INFO_bKGD)
      {
        /*
          Set image background color.
        */
        if (ping_info->bit_depth <= QuantumDepth)
          {
            image->background_color.red=ping_info->background.red;
            image->background_color.green=ping_info->background.green;
            image->background_color.blue=ping_info->background.blue;
          }
        else
          {
            image->background_color.red=
              (unsigned short)XDownScale(ping_info->background.red);
            image->background_color.green=
              (unsigned short)XDownScale(ping_info->background.green);
            image->background_color.blue=
              (unsigned short)XDownScale(ping_info->background.blue);
          }
        if (image_info->verbose)
          printf("image background  = %5d %5d %5d (bKGD = %5d %5d %5d)\n",
            image->background_color.red,image->background_color.green,
            image->background_color.blue,ping_info->background.red,
            ping_info->background.green,ping_info->background.blue);
      }
#endif

    if (ping_info->valid & PNG_INFO_tRNS)
      {
        /*
          Image has a transparent background.
        */
        transparent_color.red=ping_info->trans_values.red;
        transparent_color.green=ping_info->trans_values.green;
        transparent_color.blue=ping_info->trans_values.blue;
        transparent_color.index=ping_info->trans_values.gray;
        if (ping_info->color_type == PNG_COLOR_TYPE_GRAY)
          {
            transparent_color.red=transparent_color.index;
            transparent_color.green=transparent_color.index;
            transparent_color.blue=transparent_color.index;
          }
        if (image_info->verbose)
          {
            printf("transparent color = %5d %5d %5d (tRNS = %5d %5d %5d %5d)\n",
                transparent_color.red,transparent_color.green,
                transparent_color.blue,ping_info->trans_values.red,
                ping_info->trans_values.green,ping_info->trans_values.blue,
                ping_info->trans_values.index);
            if (ping_info->color_type == PNG_COLOR_TYPE_GRAY)
              printf("transparent color index= %5d\n",transparent_color.index);
          }
      }
#if defined(PNG_READ_sBIT_SUPPORTED)
    if (have_global_sbit)
      if ((!ping_info->valid & PNG_INFO_sBIT))
        png_set_sBIT(ping, ping_info, m->global_sbit);
#endif
    png_read_update_info(ping,ping_info);
    /*
      Initialize image structure.
    */
    image_box.left=0;
    image_box.right=(long) ping_info->width;
    image_box.top=0;
    image_box.bottom=(long) ping_info->height;
    if (mng_type == 0)
      {
        mng_width=ping_info->width;
        mng_height=ping_info->height;
        frame=image_box;
        clip=image_box;
      }
#ifndef MNG_ALWAYS_VERBOSE
    if (image_info->verbose)
#endif
      printf("  Image width=%lu, height=%lu, delay=%d\n",
        ping_info->width,ping_info->height,image->delay);

    image->compression=ZipCompression;
    image->columns=(unsigned int) ping_info->width;
    image->rows=(unsigned int) ping_info->height;
    if ((ping_info->color_type == PNG_COLOR_TYPE_PALETTE) ||
        (ping_info->color_type == PNG_COLOR_TYPE_GRAY))
      {
        image->class=PseudoClass;
        image->colors=1 << Min(ping_info->bit_depth,QuantumDepth);
        if (ping_info->color_type == PNG_COLOR_TYPE_PALETTE)
          image->colors=ping_info->num_palette;
      }
    if (image_info->ping)
      {
        png_destroy_read_struct(&ping,&ping_info,&end_info);
        CloseBlob(image);
        MngFreeStruct(m,&have_mng_structure);
        return(image);
      }
    if (image_info->verbose)
      printf("rowbytes=%d\n",ping_info->rowbytes);
    png_pixels=(unsigned char *)
      AllocateMemory(ping_info->rowbytes*image->rows*sizeof(Quantum));
    scanlines=(unsigned char **)
      AllocateMemory(image->rows*sizeof(unsigned char *));
    if ((png_pixels == (unsigned char *) NULL) ||
        (scanlines == (unsigned char **) NULL))
      ReaderExit(ResourceLimitWarning,"Memory allocation failed",image);
    if (image->class == PseudoClass)
      {
        /*
          Initialize image colormap.
        */
        image->colormap=(ColorPacket *)
          AllocateMemory(image->colors*sizeof(ColorPacket));
        if (image->colormap == (ColorPacket *) NULL)
          ReaderExit(ResourceLimitWarning,"Memory allocation failed",image);
        for (i=0; i < (int) image->colors; i++)
        {
          image->colormap[i].red=(MaxRGB*i)/Max(image->colors-1,1);
          image->colormap[i].green=(MaxRGB*i)/Max(image->colors-1,1);
          image->colormap[i].blue=(MaxRGB*i)/Max(image->colors-1,1);
        }
        if (ping_info->color_type == PNG_COLOR_TYPE_PALETTE)
          for (i=0; i < (int) image->colors; i++)
          {
            image->colormap[i].red=
              (unsigned short) UpScale(ping_info->palette[i].red);
            image->colormap[i].green=
              (unsigned short) UpScale(ping_info->palette[i].green);
            image->colormap[i].blue=
              (unsigned short) UpScale(ping_info->palette[i].blue);
          }
      }
    packets=0;
    image->pixels=(RunlengthPacket *)
      AllocateMemory(image->columns*image->rows*sizeof(RunlengthPacket));
    if (image->pixels == (RunlengthPacket *) NULL)
      {
        FreeMemory((char *) png_pixels);
        FreeMemory((char *) scanlines);
        ReaderExit(ResourceLimitWarning,"Memory allocation failed",image);
      }
    /*
      Read image scanlines.
    */
    for (i=0; i < (int) image->rows; i++)
      scanlines[i]=png_pixels+(i*ping_info->rowbytes);
    png_read_image(ping,scanlines);
    png_read_end(ping,ping_info);
    /*
      Convert PNG pixels to runlength-encoded packets.
    */
    q=image->pixels;
    SetRunlengthEncoder(q);
    if (image->class == DirectClass)
      {
        Quantum
          blue,
          green,
          red;

        if (image_info->verbose)
          printf("Converting DirectClass pixels\n");
        /*
          Convert image to DirectClass runlength-encoded packets.
        */
        if ((ping_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) ||
            (ping_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) ||
            (ping_info->valid & PNG_INFO_tRNS))
          image->matte=True;
        for (y=0; y < (int) image->rows; y++)
        {
          p=scanlines[y];
          for (x=0; x < (int) image->columns; x++)
          {
            ReadQuantum(red,p);
            green=red;
            blue=red;
            if (ping_info->color_type != PNG_COLOR_TYPE_GRAY_ALPHA &&
                ping_info->color_type != PNG_COLOR_TYPE_GRAY)
              {
                ReadQuantum(green,p);
                ReadQuantum(blue,p);
              }
            index=Opaque;
            if ((ping_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) ||
                (ping_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
              ReadQuantum(index,p);
            if (ping_info->valid & PNG_INFO_tRNS &&
                (ping_info->color_type != PNG_COLOR_TYPE_PALETTE))
              {
#if (QuantumDepth == 8)
                if (ping_info->bit_depth <= QuantumDepth)
                  {
#endif
                    if ((red == transparent_color.red) &&
                        (green == transparent_color.green) &&
                        (blue == transparent_color.blue))
                      index=Transparent;
#if (QuantumDepth == 8)
                  }
                else
                  {
                    /*
                       We are reading a 16-bit/sample PNG but are storing
                       only 8 bits.  We must compare the full 16-bit samples
                       for transparency.
                    */
                    if (ping_info->color_type == PNG_COLOR_TYPE_GRAY)
                      {
                        png_uint_16
                          gray_16;

                        gray_16 = (*(p-2) << 8) + *(p-1);

                        if (gray_16 == transparent_color.red)
                          index=Transparent;
                      }
                    else
                      {
                        png_uint_16
                          red_16,
                          green_16,
                          blue_16;

                        red_16 = (*(p-6) << 8) | *(p-5);
                        green_16 = (*(p-4) << 8) | *(p-3);
                        blue_16 = (*(p-2) << 8) | *(p-1);

                        if ((red_16 == transparent_color.red) &&
                            (green_16 == transparent_color.green) &&
                            (blue_16 == transparent_color.blue))
                          index=Transparent;
                      }
                  }
#endif
              }
#if (QuantumDepth == 8)
            if (!reduction_warning && ping_info->bit_depth > 8)
              if ((*(p-1) != *(p-2)) ||
                  ((ping_info->color_type != PNG_COLOR_TYPE_GRAY) &&
                  (*(p-3) != *(p-4))) ||
                  ((ping_info->color_type == PNG_COLOR_TYPE_RGB) &&
                  (*(p-5) != *(p-6))) ||
                  ((ping_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
                  (*(p-5) != *(p-6)) || (*(p-7) != *(p-8))))
                {
                  MagickWarning(DelegateWarning,
                      "Lossy reduction of 16-bit PNG image to 8-bit",
                      image->filename);
                  reduction_warning=True;
                }
#endif
            if ((red == q->red) && (green == q->green) && (blue == q->blue) &&
                (index == q->index) && ((int) q->length < MaxRunlength))
              q->length++;
            else
              {
                if (packets != 0)
                  q++;
                packets++;
                q->red=red;
                q->green=green;
                q->blue=blue;
                q->index=index;
                q->length=0;
              }
          }
        }
        SetRunlengthPackets(image,packets);
      }
    else
      {
        Quantum
          *quantum_scanline;

        register Quantum
          *r;

        if (image_info->verbose)
          printf("Converting PseudoClass pixels\n");
        /*
          Convert image to PseudoClass runlength-encoded packets.
        */
        quantum_scanline=(Quantum *)
          AllocateMemory(image->columns*sizeof(Quantum));
        if (quantum_scanline == (Quantum *) NULL)
          ReaderExit(ResourceLimitWarning,"Memory allocation failed",image);
        for (y=0; y < (int) image->rows; y++)
        {
          p=scanlines[y];
          r=quantum_scanline;
          switch (ping_info->bit_depth)
          {
            case 1:
            {
              register int
                bit;

              for (x=0; x < ((int) image->columns-7); x+=8)
              {
                for (bit=7; bit >= 0; bit--)
                  *r++=((*p) & (0x01 << bit) ? 0x01 : 0x00);
                p++;
              }
              if ((image->columns % 8) != 0)
                {
                  for (bit=7; bit >= (int) (8-(image->columns % 8)); bit--)
                    *r++=((*p) & (0x01 << bit) ? 0x01 : 0x00);
                }
              break;
            }
            case 2:
            {
              for (x=0; x < ((int) image->columns-3); x+=4)
              {
                *r++=(*p >> 6) & 0x03;
                *r++=(*p >> 4) & 0x03;
                *r++=(*p >> 2) & 0x03;
                *r++=(*p) & 0x03;
                p++;
              }
              if ((image->columns % 4) != 0)
                {
                  for (i=3; i >= (int) (4-(image->columns % 4)); i--)
                    *r++=(*p >> (i*2)) & 0x03;
                }
              break;
            }
            case 4:
            {
              for (x=0; x < ((int) image->columns-1); x+=2)
              {
                *r++=(*p >> 4) & 0x0f;
                *r++=(*p) & 0x0f;
                p++;
              }
              if ((image->columns % 2) != 0)
                *r++=(*p++ >> 4) & 0x0f;
              break;
            }
            case 8:
            {
              for (x=0; x < (int) image->columns; x++)
                *r++=(*p++);
              break;
            }
            case 16:
            {
              for (x=0; x < (int) image->columns; x++)
              {
                ReadQuantum(*r,p);
                r++;
#if (QuantumDepth == 8)
                if (!reduction_warning)
                  {
                    if(*(p-1) != *(p-2))
                      {
                        MagickWarning(DelegateWarning,
                            "Lossy reduction of 16-bit PNG image to 8-bit",
                            image->filename);
                        reduction_warning=True;
                      }
                  }
#endif
              }
              break;
            }
            default:
              break;
          }
          /*
            Transfer image scanline.
          */
          r=quantum_scanline;
          for (x=0; x < (int) image->columns; x++)
          {
            index=(*r++);
            if ((index == q->index) && ((int) q->length < MaxRunlength))
              q->length++;
            else
              {
                if (packets != 0)
                  q++;
                packets++;
                q->index=index;
                q->length=0;
              }
          }
        }
        FreeMemory((char *) quantum_scanline);
        SetRunlengthPackets(image,packets);
        if (image->class == PseudoClass)
          SyncImage(image);
        if (ping_info->valid & PNG_INFO_tRNS)
          {
            /*
              Image has a transparent background.
            */
            image->class=DirectClass;
            image->matte=True;
            q=image->pixels;
            for (i=0; i < packets; i++)
              {
                index=q->index;
                q->index=Opaque;
                if (ping_info->color_type == PNG_COLOR_TYPE_PALETTE)
                  {
                    if (index < ping_info->num_trans)
                      q->index=(unsigned short)UpScale(ping_info->trans[index]);
                  }
                else
                  {
                    if (index == transparent_color.index)
                      q->index=Transparent;
                  }
                q++;
              }
          }
      }
#if (QuantumDepth == 8)
    if (image->depth > 8)
      image->depth = 8;
#endif
    if (ping_info->num_text > 0)
      for (i=0; i < ping_info->num_text; i++)
        {
          if (strcmp(ping_info->text[i].key,"Comment") == 0)
            ReadTextChunk(ping_info,i,&image->comments);
          if (strcmp(ping_info->text[i].key,"Delay") == 0)
            if (image_info->delay == (char *) NULL)
              {
                char
                  *delay;

                delay=(char *) NULL;
                ReadTextChunk(ping_info,i,&delay);
                image->delay=atoi(delay);
                FreeMemory(delay);
              }
          if (strcmp(ping_info->text[i].key,"Description") == 0)
            ReadTextChunk(ping_info,i,&image->comments);
          if (strcmp(ping_info->text[i].key,"Directory") == 0)
            ReadTextChunk(ping_info,i,&image->directory);
          if (strcmp(ping_info->text[i].key,"Label") == 0)
            ReadTextChunk(ping_info,i,&image->label);
          if (strcmp(ping_info->text[i].key,"Montage") == 0)
            ReadTextChunk(ping_info,i,&image->montage);
          if (strcmp(ping_info->text[i].key,"Page") == 0)
            {
              if (image_info->page == (char *) NULL)
                ReadTextChunk(ping_info,i,&image->page);
            }
          if (strcmp(ping_info->text[i].key,"Scene") == 0)
            {
              char
                *scene;

              scene=(char *) NULL;
              ReadTextChunk(ping_info,i,&scene);
              image->scene=atoi(scene);
              FreeMemory(scene);
            }
          if (strcmp(ping_info->text[i].key,"Signature") == 0)
            ReadTextChunk(ping_info,i,&image->signature);
          if (strcmp(ping_info->text[i].key,"Title") == 0)
            ReadTextChunk(ping_info,i,&image->label);
        }
#ifdef MNG_OBJECT_BUFFERS
    /*
      Store the object if necessary.
    */
    if (object_id && !m->frozen[object_id])
      {
        if (m->ob[object_id] == (MngBuffer *)NULL)
          {
            /*
              create a new object buffer.
            */
            if (m->verbose)
              printf("Allocating memory for object buffer[%d]\n",object_id);
            m->ob[object_id]=(MngBuffer *) AllocateMemory(sizeof(MngBuffer));
            if (m->ob[object_id] != (MngBuffer *)NULL)
              {
                m->ob[object_id]->image=(Image *) NULL;
                m->ob[object_id]->reference_count=1;
              }
          }
        if ((m->ob[object_id] == (MngBuffer *) NULL) ||
            m->ob[object_id]->frozen)
          {
            if (m->ob[object_id] == (MngBuffer *)NULL)
              MagickWarning(ResourceLimitWarning,
                "Memory allocation of MNG object buffer failed",
                image->filename);
            if (m->ob[object_id]->frozen)
              MagickWarning(ResourceLimitWarning,
                "Cannot overwrite frozen MNG object buffer",image->filename);
          }
        else
          {
            png_uint_32
              width,
              height;

            int
              bit_depth,
              color_type,
              interlace_method,
              compression_method,
              filter_method;

            if (m->verbose)
              {
                if (m->ob[object_id]->image != (Image *)NULL)
                  printf("Creating object buffer[%d]\n",object_id);
                else
                  printf("Updating object buffer[%d]\n",object_id);
              }
            if (m->ob[object_id]->image != (Image *)NULL)
              DestroyImage(m->ob[object_id]->image);
            image->orphan=True;
            m->ob[object_id]->image=
              CloneImage(image,image->columns,image->rows,True);
            image->orphan=False;
            if (m->ob[object_id]->image == (Image *)NULL)
              MagickWarning(ResourceLimitWarning,
                "Cloning image for object buffer failed",image->filename);
            else
              {
                if (m->verbose)
                  printf("Copied image to object buffer[%d]\n",object_id);
                m->ob[object_id]->image->file=(FILE *)NULL;
              }
            png_get_IHDR(ping,ping_info,&width,&height,&bit_depth,&color_type,
              &interlace_method,&compression_method,&filter_method);
            m->ob[object_id]->width=width;
            m->ob[object_id]->height=height;
            m->ob[object_id]->color_type=color_type;
            m->ob[object_id]->sample_depth=bit_depth;
            m->ob[object_id]->interlace_method=interlace_method;
            m->ob[object_id]->compression_method=compression_method;
            m->ob[object_id]->filter_method=filter_method;
            if (ping_info->valid & PNG_INFO_PLTE)
              {
                int
                  num_palette;

                png_colorp
                  plte;

                /*
                  Copy the PLTE to the object buffer.
                */
                png_get_PLTE(ping, ping_info, &plte, &num_palette);
                m->ob[object_id]->plte_length = num_palette;
                for (i=0; i<num_palette; i++)
                {
                  m->ob[object_id]->plte[i]=plte[i];
                }
              }
            else
                m->ob[object_id]->plte_length=0;
          }
      }
#endif
    /*
      Free memory.
    */
    png_destroy_read_struct(&ping,&ping_info,&end_info);
    FreeMemory((char *) png_pixels);
    FreeMemory((char *) scanlines);
#ifndef MNG_ALWAYS_VERBOSE
    if (image_info->verbose)
#endif
      printf("Destroyed the png read structure\n");
    if (mng_type)
      {
        MngBox
          crop_box;

        /*
          Crop_box is with respect to the upper left corner of the MNG.
        */
        crop_box.left=image_box.left+m->x_off[object_id];
        crop_box.right=image_box.right+m->x_off[object_id];
        crop_box.top=image_box.top+m->y_off[object_id];
        crop_box.bottom=image_box.bottom+m->y_off[object_id];
        crop_box=mng_minimum_box(crop_box,clip);
        crop_box=mng_minimum_box(crop_box,frame);
        crop_box=mng_minimum_box(crop_box,m->object_clip[object_id]);
        if ((crop_box.left != (image_box.left+m->x_off[object_id])) ||
            (crop_box.right != (image_box.right+m->x_off[object_id])) ||
            (crop_box.top != (image_box.top+m->y_off[object_id])) ||
            (crop_box.bottom != (image_box.bottom+m->y_off[object_id])))
          {
            if ((crop_box.left < crop_box.right) &&
                (crop_box.top < crop_box.bottom))
              {
                Image
                  *p;

                RectangleInfo
                  crop_info;

                char
                  *page,
                  page_geometry[MaxTextExtent];


                /*
                  Crop_info is with respect to the upper left corner of
                  the image.
                */
                crop_info.x=crop_box.left-m->x_off[object_id];
                crop_info.y=crop_box.top-m->y_off[object_id];
                crop_info.width=(unsigned int)
                  (crop_box.right-crop_box.left);
                crop_info.height=(unsigned int)
                  (crop_box.bottom-crop_box.top);
                page=image->page;
                image->page=(char *) NULL;
                FormatString(page_geometry,"%lux%lu+0+0",
                  image->columns,image->rows);
                image->page=PostscriptGeometry(page_geometry);
                image->orphan=True;
                p=CropImage(image, &crop_info);
                image->orphan=False;
                if (p == (Image *) NULL)
                  {
                    if (m->verbose)
                      MagickWarning(ResourceLimitWarning,"Unable to crop image",
                       "Who knows why?");
                    assert(image->page != (char *) NULL);
                    FreeMemory((char *) image->page);
                    image->page=page;
                  }
                else
                  {
                    image->columns=p->columns;
                    image->rows=p->rows;
                    image->packets=p->columns*p->rows;
                    if (image->pixels != (RunlengthPacket *) NULL)
                      FreeMemory((char *) image->pixels);
                    image->pixels=p->pixels;
                    if (image->pixels == (RunlengthPacket *) NULL)
                      MagickWarning(ResourceLimitWarning,"Unable to crop image",
                       "image->pixels == NULL");
                    p->pixels=(RunlengthPacket *)NULL;
                    if (image->packed_pixels != (unsigned char *) NULL)
                      FreeMemory((char *) image->packed_pixels);
                    image->packed_pixels = p->packed_pixels;
                    p->packed_pixels=(unsigned char *)NULL;
                    p->orphan=True;  /* don't mess up links or close FILE */
                    p->file=(FILE *)NULL;
                    DestroyImage(p);
                    FormatString(page_geometry,"%lux%lu%+ld%+ld",
                      image->columns, image->rows,crop_box.left,crop_box.top);
                    if (image->page != (char *) NULL)
                      FreeMemory((char *) image->page);
                    image->page=PostscriptGeometry(page_geometry);
                    CondenseImage(image);
                    if (m->verbose)
                      printf("  object_id %d cropped to geometry=%s\n",
                        object_id, page_geometry);
                  }
              }
            else
              {
                /*
                  No pixels in crop area.  The MNG spec still requires
                  a layer, though, so make a single transparent pixel in
                  the top left corner.
                */
                image->columns=(unsigned int)1;
                image->rows=(unsigned int)1;
                image->packets=(unsigned long)1;
                image->pixels=(RunlengthPacket *) ReallocateMemory((char *)
                  image->pixels,sizeof(RunlengthPacket));
                if (image->pixels == (RunlengthPacket *) NULL)
                  {
                    MagickWarning(ResourceLimitWarning,
                      "Unable to reallocate 1x1 image",
                      "Memory allocation failed");
                    return(False);
                  }
                image->matte=True;
                image->colors=2;
                SetImage(image);
                FormatString(page_geometry,"1x1+0+0");
                if (image->page != (char *) NULL)
                  FreeMemory((char *) image->page);
                image->page=PostscriptGeometry(page_geometry);
                CondenseImage(image);
                if (m->verbose)
                  printf("  object_id %d cropped to geometry=%s\n",
                    object_id, page_geometry);
              }
          }
        if (image_info->coalesce_frames)
          {
            image->background_color = mng_background_color;
            MNGCoalesce(image);
          }
      }
  } while (strcmp(image_info->magick,"MNG") == 0);
#ifndef MNG_ALWAYS_VERBOSE
  if (image_info->verbose)
#endif
    printf("Supposedly there are %d visible images.\n",image_found);
  if (image_info->insert_backdrops && !image_found && (mng_width > 0) &&
      (mng_height > 0))
    {
      char
        background_page_geometry[MaxTextExtent];

      /*
        Insert a background layer if nothing else was found.
      */
      if (image->pixels != (RunlengthPacket *) NULL)
        {
          /*
            Allocate next image structure.
          */
          AllocateNextImage(image_info,image);
          if (image->next == (Image *) NULL)
            {
              DestroyImages(image);
              MngFreeStruct(m,&have_mng_structure);
              return((Image *) NULL);
            }
          image=image->next;
        }
      image->columns=mng_width;
      image->rows=mng_height;
      FormatString(background_page_geometry,"%ux%u%+d%+d",
        image->columns,image->rows,0,0);
      if (image->page != (char *) NULL)
        FreeMemory((char *) image->page);
      image->page=PostscriptGeometry(background_page_geometry);
      image->packets=image->columns*image->rows;
      image->pixels=(RunlengthPacket *)
        AllocateMemory(image->packets*sizeof(RunlengthPacket));
      if (image->pixels == (RunlengthPacket *) NULL)
        {
          MagickWarning(ResourceLimitWarning,
           "Memory allocation failed for background layer",(char *) NULL);
          MngFreeStruct(m,&have_mng_structure);
          return((Image *) NULL);
        }
      image->background_color=mng_background_color;
      image->matte=False;
      SetImage(image);
      CondenseImage(image);
      image_found++;
#ifndef MNG_ALWAYS_VERBOSE
      if (image_info->verbose)
#endif
        printf("Inserted an empty %s frame behind empty MNG.\n",
          background_page_geometry);
    }
  if (ticks_per_second)
     image->delay=100*final_delay/ticks_per_second;
  else
     image->delay=final_delay;
  if (image_info->verbose)
     printf("terminal delay=%d (final_delay=%ld, tps=%ld)\n",image->delay,
       final_delay,ticks_per_second);
  while (image->previous != (Image *) NULL)
  {
    image_count++;
    if (image_count>10*image_found)
      {
        MagickWarning(DelegateWarning,
          "Linked list is corrupted, beginning of list not found",
          image_info->filename);
        return(Image *)NULL;
      }
    image=image->previous;
    if (image->next == (Image *)NULL)
      MagickWarning(DelegateWarning,
       "Linked list is corrupted; next_image is NULL",image_info->filename);
  }
  if (ticks_per_second && image_found > 1 && image->next == (Image *)NULL)
    MagickWarning(DelegateWarning,
     "image->next for first image is NULL but shouldn't be.",
     image_info->filename);
  if (!image_found)
    {
      MagickWarning(DelegateWarning,
        "No visible images in file",image_info->filename);
      if (image != (Image *) NULL)
        DestroyImages(image);
      MngFreeStruct(m,&have_mng_structure);
      return((Image *) NULL);
    }
#ifndef MNG_ALWAYS_VERBOSE
  if (image_info->verbose)
#endif
    printf("Finished loading %d visible images.\n",image_found);
  CloseBlob(image);
  MngFreeStruct(m,&have_mng_structure);
  have_mng_structure=False;
#ifndef MNG_ALWAYS_VERBOSE
  if (image_info->verbose)
#endif
    printf("Free'ed the mng structure if there was one.\n");
  return(image);
}
#else
Export Image *ReadPNGImage(const ImageInfo *image_info)
{
  MagickWarning(MissingDelegateWarning,"PNG library is not available",
    image_info->filename);
  return((Image *) NULL);
}
#endif

#if defined(HasPNG)
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   W r i t e P N G I m a g e                                                 %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  Method WritePNGImage writes an image in the Portable Network Graphics
%  encoded image format.
%
%  MNG support written by Glenn Randers-Pehrson, randeg@alum.rpi.edu
%
%  The format of the WritePNGImage method is:
%
%      unsigned int WritePNGImage(const ImageInfo *image_info,Image *image)
%
%  A description of each parameter follows.
%
%    o status: Method WritePNGImage return True if the image is written.
%      False is returned is there is a memory shortage or if the image file
%      fails to write.
%
%    o image_info: Specifies a pointer to an ImageInfo structure.
%
%    o image:  A pointer to an Image structure.
%
%
%  To do (as of version 4.2.9, August 29, 1999 -- glennrp -- see also
%    "To do" under ReadPNGImage):
%
%    Preserve all unknown and not-yet-handled known chunks found in input
%    PNG file and copy them  into output PNG files according to the PNG
%    copying rules.
%
%    Write the iCCP chunk at MNG level when (image->color_profile.length > 0)
%    Write the iCCP chunk at PNG level if appropriate, when libpng has
%    implemented iCCP.
%
%    Improve selection of color type (use indexed-colour or indexed-colour
%    with tRNS when 256 or fewer unique RGBA values are present).
%
%    Figure out what to do with "dispose=<restore-to-previous>" (dispose==3)
%    This will be complicated if we limit ourselves to generating MNG-LC
%    files.  For now we ignore disposal method 3 and simply overlay the next
%    image on it.
%
%    Check for identical PLTE's or PLTE/tRNS combinations and use a
%    global MNG PLTE or PLTE/tRNS combination when appropriate.
%    [mostly done 15 June 1999 but still need to take care of tRNS]
%
%    Check for identical sRGB and replace with a global sRGB (and remove
%    gAMA/cHRM if sRGB is found; check for identical gAMA/cHRM and
%    replace with global gAMA/cHRM (or with sRGB if appropriate; replace
%    local gAMA/cHRM with local sRGB if appropriate).
%
%    Check for identical sBIT chunks and write global ones.
%
%    Provide option to skip writing the signature tEXt chunks.
%
%    Use signatures to detect identical objects and reuse the first
%    instance of such objects instead of writing duplicate objects.
%
%    Use a smaller-than-32k value of compression window size when
%    appropriate.
%
%    Encode JNG datastreams.
%
%    Provide an option to force LC files (to ensure exact framing rate)
%    instead of VLC.
%
%    Provide an option to force VLC files instead of LC, even when offsets
%    are present.  This will involve expanding the embedded images with a
%    transparent region at the top and/or left.
*/

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

void PNGLong(png_bytep p,png_uint_32 value)
{
  *p++=(png_byte) ((value >> 24) & 0xff);
  *p++=(png_byte) ((value >> 16) & 0xff);
  *p++=(png_byte) ((value >> 8) & 0xff);
  *p++=(png_byte) (value & 0xff);
}

void PNGShort(png_bytep p,png_uint_16 value)
{
  *p++=(png_byte) ((value >> 8) & 0xff);
  *p++=(png_byte) (value & 0xff);
}

void PNGType(png_bytep p,png_bytep type)
{
  *p++=(*type++);
  *p++=(*type++);
  *p++=(*type++);
  *p++=(*type++);
}

static void WriteTextChunk(const ImageInfo *image_info,png_info *ping_info,
  char *keyword,char *value)
{
  register int
    i;

  i=ping_info->num_text++;
  ping_info->text[i].key=keyword;
  ping_info->text[i].text=value;
  ping_info->text[i].text_length=Extent(value);
  ping_info->text[i].compression=
    image_info->compression == NoCompression ||
    (image_info->compression == UndefinedCompression &&
    ping_info->text[i].text_length < 128) ? -1 : 0;
  if (image_info->verbose)
    printf("image_info->compression = %d for text chunk %d\n",
      image_info->compression,i);
}

#if defined(__cplusplus) || defined(c_plusplus)
}
#endif

Export unsigned int WritePNGImage(const ImageInfo *image_info,Image *image)
{
  int
    all_images_are_gray,
    equal_backgrounds,
    equal_chrms,
    equal_gammas,
    equal_palettes,
    equal_physs,
    equal_srgbs,
    framing_mode,
    have_write_global_chrm,
    have_write_global_gama,
    have_write_global_plte,
    have_write_global_srgb,
    image_count,
    need_defi,
    need_fram,
    need_iterations,
    need_local_plte,
    need_matte,
    old_framing_mode,
    rowbytes,
    save_image_depth,
    use_global_plte,
    x,
    y;

  register int
    i,
    j;

  register RunlengthPacket
    *p;

  register unsigned char
    *q;

  RectangleInfo
    page_info;

  png_info
    *ping_info;

  png_struct
    *ping;

  unsigned char
    chunk[800],
    *png_pixels,
    **scanlines;

  unsigned int
    delay,
    final_delay,
    initial_delay,
    matte,
#ifdef MNG_LEVEL
    mng_level,
#endif
    scene,
    status,
    ticks_per_second;

  unsigned short
    value;

  /*
    Open image file.
  */
#ifdef MNG_LEVEL
  mng_level=MNG_LEVEL;
#endif
  status=OpenBlob(image_info,image,WriteBinaryType);
  if (status == False)
    WriterExit(FileOpenWarning,"Unable to open file",image);
  if (image_info->verbose)
    printf("Writing PNG image\n");
  need_local_plte=True;
  use_global_plte=False;
  page_info.width=0;
  page_info.height=0;
  page_info.x=0;
  page_info.y=0;
  have_write_global_plte=False;
  need_local_plte=True;
  have_write_global_srgb=False;
  have_write_global_gama= False;
  have_write_global_chrm=False;
  need_defi=False;
  need_fram=False;
  need_matte=False;
  framing_mode=1;
  old_framing_mode=1;

  if (image_info->adjoin)
    {
      Image
        *next_image;

      unsigned int
        need_geom,
        height,
        width;

      unsigned short
        red,
        green,
        blue;
      /*
        Determine image bounding box.
      */
      need_geom=True;
      if (image_info->page != (char *) NULL)
        {
          (void) ParseGeometry(image_info->page,&page_info.x,&page_info.y,
            &page_info.width,&page_info.height);
          need_geom=False;
        }
      /*
        Check all the scenes.
      */
      initial_delay=image->delay;
      need_iterations=False;
      need_local_plte=False;
      equal_backgrounds=True;
      all_images_are_gray=True;
      equal_chrms=image->chromaticity.white_point.x != 0.0;
      equal_gammas=True;
      equal_srgbs=True;
      equal_palettes=False;
      equal_physs=True;
      image_count=0;
      for (next_image=image; next_image != (Image *) NULL; )
      {
        if (next_image->page != (char *) NULL)
          {
            (void) ParseGeometry(next_image->page,&page_info.x,
              &page_info.y, &width, &height);
          }
        else
          {
            page_info.x=0;
            page_info.y=0;
          }
        if (need_geom)
          {
            if ((next_image->columns+page_info.x) > page_info.width)
              page_info.width=next_image->columns+page_info.x;
            if ((next_image->rows+page_info.y) > page_info.height)
              page_info.height=next_image->rows+page_info.y;
          }
        if (page_info.x || page_info.y)
          need_defi=True;
        if (next_image->matte)
          need_matte=True;
        if (next_image->dispose >= 2)
          if (next_image->matte || page_info.x || page_info.y ||
              ((next_image->columns < page_info.width) &&
               (next_image->rows < page_info.height)))
            need_fram=True;
        if (next_image->iterations)
          need_iterations=True;
        final_delay=next_image->delay;
        if (final_delay != initial_delay)
          need_fram=1;
#ifdef PNG_WRITE_EMPTY_PLTE_SUPPORTED
        /*
          check for global palette possibility.
        */
        if (!IsGrayImage(image))
          all_images_are_gray=False;
        equal_palettes=PalettesAreEqual(image_info,image,next_image);
        if (!use_global_plte)
          use_global_plte=equal_palettes;
        if (!need_local_plte)
          need_local_plte=!equal_palettes;
#else
        need_local_plte=True;
#endif
        if (next_image->next != (Image *)NULL)
          {
            if (next_image->background_color.red !=
                next_image->next->background_color.red ||
                next_image->background_color.green !=
                next_image->next->background_color.green ||
                next_image->background_color.blue !=
                next_image->next->background_color.blue)
              equal_backgrounds=False;
            if (next_image->gamma != next_image->next->gamma)
              equal_gammas=False;
            if (next_image->rendering_intent != 
                next_image->next->rendering_intent)
              equal_srgbs=False;
            if ((next_image->units != next_image->next->units) ||
                (next_image->x_resolution != next_image->next->x_resolution) ||
                (next_image->y_resolution != next_image->next->y_resolution))
              equal_physs=False;
            if (equal_chrms)
              {
                if (next_image->chromaticity.red_primary.x !=
                    next_image->next->chromaticity.red_primary.x ||
                    next_image->chromaticity.red_primary.y !=
                    next_image->next->chromaticity.red_primary.y ||
                    next_image->chromaticity.green_primary.y !=
                    next_image->next->chromaticity.green_primary.x ||
                    next_image->chromaticity.blue_primary.x !=
                    next_image->next->chromaticity.green_primary.y ||
                    next_image->chromaticity.blue_primary.x !=
                    next_image->next->chromaticity.blue_primary.x ||
                    next_image->chromaticity.blue_primary.y !=
                    next_image->next->chromaticity.blue_primary.y ||
                    next_image->chromaticity.white_point.x !=
                    next_image->next->chromaticity.white_point.x ||
                    next_image->chromaticity.white_point.y !=
                    next_image->next->chromaticity.white_point.y)
                  equal_chrms=False;
              }
          }
        image_count++;
        next_image=next_image->next;
      }
      if (image_count < 2)
        {
          equal_backgrounds=False;
          equal_chrms=False;
          equal_gammas=False;
          equal_srgbs=False;
          equal_physs=False;
          use_global_plte=False;
          need_local_plte=True;
        }
     if (image_info->verbose)
       {
         printf("initial delay=%d, final delay=%d\n",initial_delay,final_delay);
         printf("need_defi=%d, need_fram=%d\n",need_defi,need_fram);
       }
     if (!need_fram)
       {
         /*
           Only certain framing rates 100/n are exactly representable without
           the FRAM chunk but we'll allow some slop in VLC files
         */
         if (final_delay == 0)
           {
             if (need_iterations)
               {
                 /*
                   It's probably a GIF with loop; don't run it *too* fast.
                 */
                 final_delay=10;
                 MagickWarning(DelegateWarning,
                   "input has zero delay between all frames; assuming 10 cs",
                   image->filename);
               }
             else
               ticks_per_second=0;
           }
         if (final_delay > 0)
           ticks_per_second=100/final_delay;
         if (final_delay > 50)
           ticks_per_second=2;
         if (final_delay > 75)
           ticks_per_second=1;
         if (final_delay > 125)
           need_fram=True;
         if (image_info->verbose)
            printf("final delay=%d, need_fram=%d\n",final_delay,need_fram);
         if (need_defi && final_delay > 2 && (final_delay != 4) &&
             (final_delay != 5) && (final_delay != 10) && (final_delay != 20) &&
             (final_delay != 25) && (final_delay != 50) && (final_delay != 100))
           need_fram=True;  /* make it exact; we cannot have VLC anyway */
       }
     if (need_fram)
        ticks_per_second = 100;
     /*
        If pseudocolor, we should also check to see if all the
        palettes are identical and write a global PLTE if they are.
        ../glennrp Feb 99.
     */
     /*
        Write the MNG version 0.96 signature and MHDR chunk.
     */
     (void) WriteBlob(image,8,"\212MNG\r\n\032\n");
     MSBFirstWriteLong(image,28L);  /* chunk data length = 28 */
     PNGType(chunk,mng_MHDR);
     PNGLong(chunk+4,page_info.width);
     PNGLong(chunk+8,page_info.height);
     PNGLong(chunk+12,ticks_per_second);
     PNGLong(chunk+16,0L);  /* layer count = unknown */
     PNGLong(chunk+20,0L);  /* frame count = unknown */
     PNGLong(chunk+24,0L);  /* play time = unknown   */
     if (need_matte)
       {
         if (need_defi || need_fram || use_global_plte)
           PNGLong(chunk+28,11L);    /* simplicity =  LC */
         else
           PNGLong(chunk+28,9L);    /* simplicity = VLC */
       }
     else
       {
         if (need_defi || need_fram || use_global_plte)
           PNGLong(chunk+28,3L);    /* simplicity =  LC, no transparency */
         else
           PNGLong(chunk+28,1L);    /* simplicity = VLC, no transparency */
       }
     (void) WriteBlob(image,32,(char *) chunk);
     MSBFirstWriteLong(image,crc32(0,chunk,32));
     if ((image->previous == (Image *) NULL) &&
         (image->next != (Image *) NULL) && (image->iterations != 1))
       {
         /*
           Write MNG TERM chunk
         */
         MSBFirstWriteLong(image,10L);  /* data length = 10 */
         PNGType(chunk,mng_TERM);
         chunk[4]=3;  /* repeat animation */
         chunk[5]=0;  /* show last frame when done */
         PNGLong(chunk+6, (png_uint_32)(ticks_per_second*final_delay/100));
         if (image_info->verbose)
            printf(
             "Wrote MNG TERM chunk with delay=%d (tps=%d, final_delay=%d)\n",
              ticks_per_second*final_delay/100,ticks_per_second,final_delay);
         if (image->iterations == 0)
           PNGLong(chunk+10, PNG_MAX_UINT);
         else
           PNGLong(chunk+10, (png_uint_32)image->iterations);
         (void) WriteBlob(image,14,(char *) chunk);
         MSBFirstWriteLong(image,crc32(0,chunk,14));
       }
     /*
       To do: check for cHRM+gAMA == sRGB, and write sRGB instead.
     */
     if ((image_info->colorspace==sRGBColorspace || image->rendering_intent) &&
          equal_srgbs)
       {
         /*
           Write MNG sRGB chunk
         */
         MSBFirstWriteLong(image,1L);
         PNGType(chunk,mng_sRGB);
         chunk[4]=image->rendering_intent+1;
         (void) WriteBlob(image,5,(char *) chunk);
         MSBFirstWriteLong(image,crc32(0,chunk,5));
         have_write_global_srgb=True;
       }
     else
       {
         if (image->gamma && equal_gammas)
           {
             /*
                Write MNG gAMA chunk
             */
             MSBFirstWriteLong(image,4L);
             PNGType(chunk,mng_gAMA);
             PNGLong(chunk+4, (unsigned long) (100000*image->gamma+0.5));
             (void) WriteBlob(image,8,(char *) chunk);
             MSBFirstWriteLong(image,crc32(0,chunk,8));
             have_write_global_gama=True;
           }
         if (equal_chrms)
           {
             /*
                Write MNG cHRM chunk
             */
             MSBFirstWriteLong(image,32L);
             PNGType(chunk,mng_cHRM);
             PNGLong(chunk+4,(unsigned long)
               (100000*image->chromaticity.white_point.x+0.5));
             PNGLong(chunk+8,(unsigned long)
               (100000*image->chromaticity.white_point.y+0.5));
             PNGLong(chunk+12,(unsigned long)
               (100000*image->chromaticity.red_primary.x+0.5));
             PNGLong(chunk+16,(unsigned long)
               (100000*image->chromaticity.red_primary.y+0.5));
             PNGLong(chunk+20,(unsigned long)
               (100000*image->chromaticity.green_primary.x+0.5));
             PNGLong(chunk+24,(unsigned long)
               (100000*image->chromaticity.green_primary.y+0.5));
             PNGLong(chunk+28,(unsigned long)
               (100000*image->chromaticity.blue_primary.x+0.5));
             PNGLong(chunk+32,(unsigned long)
               (100000*image->chromaticity.blue_primary.y+0.5));
             (void) WriteBlob(image,36,(char *) chunk);
             MSBFirstWriteLong(image,crc32(0,chunk,36));
             have_write_global_chrm=True;
           }
       }
     if (image->x_resolution && image->y_resolution && equal_physs)
       {
         /*
            Write MNG pHYs chunk
         */
         MSBFirstWriteLong(image,9L);
         PNGType(chunk,mng_pHYs);
         if (image->units == PixelsPerInchResolution)
           {
             PNGLong(chunk+4,(unsigned long)
               (image->x_resolution*100.0/2.54+0.5));
             PNGLong(chunk+8,(unsigned long)
               (image->y_resolution*100.0/2.54+0.5));
             chunk[12]=1;
           }
         else
           {
             if (image->units==PixelsPerCentimeterResolution)
               {
                 PNGLong(chunk+4,(unsigned long)
                   (image->x_resolution*100.0+0.5));
                 PNGLong(chunk+8,(unsigned long)
                   (image->y_resolution*100.0+0.5));
                 chunk[12]=1;
               }
             else
               {
                 PNGLong(chunk+4,(unsigned long) (image->x_resolution+0.5));
                 PNGLong(chunk+8,(unsigned long) (image->y_resolution+0.5));
                 chunk[12]=0;
               }
           }
         (void) WriteBlob(image,13,(char *) chunk);
         MSBFirstWriteLong(image,crc32(0,chunk,13));
       }
     /*
       Write MNG BACK chunk and global bKGD chunk
     */
     MSBFirstWriteLong(image,6L);
     PNGType(chunk,mng_BACK);
     red=(unsigned short) UpScale(image->background_color.red);
     green=(unsigned short) UpScale(image->background_color.green);
     blue=(unsigned short) UpScale(image->background_color.blue);
     PNGShort(chunk+4,red);
     PNGShort(chunk+6,green);
     PNGShort(chunk+8,blue);
     (void) WriteBlob(image,10,(char *) chunk);
     MSBFirstWriteLong(image,crc32(0,chunk,10));
     if (equal_backgrounds)
       {
         MSBFirstWriteLong(image,6L);
         PNGType(chunk,mng_bKGD);
         (void) WriteBlob(image,10,(char *) chunk);
         MSBFirstWriteLong(image,crc32(0,chunk,10));
       }
     if (!need_local_plte && IsPseudoClass(image) && !all_images_are_gray)
       {
         long
           data_length;

         /*
           Write MNG PLTE chunk
         */
         data_length=3*image->colors;
         MSBFirstWriteLong(image,data_length);
         PNGType(chunk,mng_PLTE);
         for (i=0; i < (int) image->colors; i++)
         {
           chunk[4+i*3]=
             (unsigned char) DownScale(image->colormap[i].red)&0xff;
           chunk[5+i*3]=
             (unsigned char) DownScale(image->colormap[i].green)&0xff;
           chunk[6+i*3]=
             (unsigned char) DownScale(image->colormap[i].blue)&0xff;
         }
         (void) WriteBlob(image,data_length+4,(char *) chunk);
         MSBFirstWriteLong(image,crc32(0,chunk,data_length+4));
         have_write_global_plte=True;
       }
    }
  scene=0;
  delay=0;
  equal_palettes=False;
  do
  {
    /*
      If we aren't using a global palette for the entire MNG, check to
      see if we can use one for two or more consecutive images.
    */
    if (need_local_plte && use_global_plte && !all_images_are_gray)
      {
        if (IsPseudoClass(image))
          {
            /*
              When equal_palettes is true, this image has the same palette
              as the previous PseudoClass image
            */
            have_write_global_plte=equal_palettes;
            equal_palettes=PalettesAreEqual(image_info,image,image->next);
            if (equal_palettes && !have_write_global_plte)
              {
                /*
                  Write MNG PLTE chunk
                */
                long
                  data_length;

                data_length=3*image->colors;
                MSBFirstWriteLong(image,data_length);
                PNGType(chunk,mng_PLTE);
                for (i=0; i < (int) image->colors; i++)
                {
                  chunk[4+i*3]=
                    (unsigned char) DownScale(image->colormap[i].red) & 0xff;
                  chunk[5+i*3]=
                    (unsigned char) DownScale(image->colormap[i].green) & 0xff;
                  chunk[6+i*3]=
                    (unsigned char) DownScale(image->colormap[i].blue) & 0xff;
                }
                (void) WriteBlob(image,data_length+4,(char *) chunk);
                MSBFirstWriteLong(image,crc32(0,chunk,data_length+4));
                have_write_global_plte=True;
              }
          }
        else
          have_write_global_plte=False;
      }
    if (need_defi)
      {
        int
          previous_x,
          previous_y;

        unsigned int
          width,
          height;

        if (scene)
          {
            previous_x=page_info.x;
            previous_y=page_info.y;
          }
        else
          {
            previous_x=0;
            previous_y=0;
          }
        if (image->page != (char *) NULL)
          {
            (void) ParseGeometry(image->page,&page_info.x,&page_info.y,
               &width,&height);
          }
        else
          {
            page_info.x=0;
            page_info.y=0;
          }
        if ((page_info.x !=  previous_x) || (page_info.y != previous_y))
          {
             MSBFirstWriteLong(image,12L);  /* data length = 12 */
             PNGType(chunk,mng_DEFI);
             chunk[4]=0; /* object 0 MSB */
             chunk[5]=0; /* object 0 LSB */
             chunk[6]=0; /* visible  */
             chunk[7]=0; /* abstract */
             PNGLong(chunk+8,page_info.x);
             PNGLong(chunk+12,page_info.y);
             (void) WriteBlob(image,16,(char *) chunk);
             MSBFirstWriteLong(image,crc32(0,chunk,16));
          }
      }
    /*
      Allocate the PNG structures
    */
    TransformRGBImage(image,RGBColorspace);
#ifdef PNG_USER_MEM_SUPPORTED
    ping = png_create_write_struct_2(PNG_LIBPNG_VER_STRING, (void *) NULL,
      PNGErrorHandler,PNGWarningHandler, (void *) NULL,
      (png_malloc_ptr) png_IM_malloc,  (png_free_ptr) png_IM_free);
#else
    ping=png_create_write_struct(PNG_LIBPNG_VER_STRING,(void *) NULL,
      PNGErrorHandler,PNGWarningHandler);
#endif
    if (ping == (png_struct *) NULL)
      WriterExit(ResourceLimitWarning,"Memory allocation failed",image);
    ping_info=png_create_info_struct(ping);
    if (ping_info == (png_info *) NULL)
      {
        png_destroy_write_struct(&ping,(png_info **) NULL);
        WriterExit(ResourceLimitWarning,"Memory allocation failed",image);
      }
    png_set_write_fn(ping, image, png_put_data, png_flush_data);
    png_pixels=(unsigned char *) NULL;
    scanlines=(unsigned char **) NULL;
    if (setjmp(ping->jmpbuf))
      {
        /*
          PNG write failed.
        */
        png_destroy_write_struct(&ping,&ping_info);
        if (scanlines != (unsigned char **) NULL)
          FreeMemory((char *) scanlines);
        if (png_pixels != (unsigned char *) NULL)
          FreeMemory((char *) png_pixels);
        CloseBlob(image);
        return(False);
      }
    /*
      Prepare PNG for writing.
    */
#ifdef PNG_WRITE_EMPTY_PLTE_SUPPORTED
    png_permit_empty_plte(ping, True);
#endif
    ping_info->width=image->columns;
    ping_info->height=image->rows;
    save_image_depth=image->depth;
    ping_info->bit_depth=save_image_depth;
    if (IsMonochromeImage(image))
      ping_info->bit_depth=1;
#if (QuantumDepth == 16)
    if (ping_info->bit_depth == 16)
      {
        /*
          Determine if bit depth can be reduced from 16 to 8.
        */

        int
          ok_to_reduce;

        p=image->pixels;
        for (i=0; i < (int) (image->packets-1); i++)
        {
          ok_to_reduce=((((p->red >> 8) & 0xff) == (p->red & 0xff)) &&
            (((p->green >> 8) & 0xff) == (p->green & 0xff)) &&
            (((p->blue >> 8) & 0xff) == (p->blue & 0xff)) &&
            (((!image->matte || ((p->index >> 8) & 0xff) == (p->index & 0xff)))));
          if (!ok_to_reduce)
            {
              if (image_info->verbose)
                {
                  int ii;
                  printf("Cannot reduce 16-bit samples to 8-bit because\n");
                  printf("packet %d has ",i);
                  printf("  red=%04x, ",p->red);
                  printf("green=%04x, ",p->green);
                  printf(" blue=%04x",p->blue);
                  if(image->matte)
                     printf(", alpha=%04x",p->index);
                  printf(".\n");
                  printf("\nPackets:\n");
                  p=image->pixels;
                }
              break;
            }
          p++;
        }
        if (ok_to_reduce)
          {
            if (image_info->verbose)
              printf("Reducing 16-bit samples to 8-bit.\n");
            ping_info->bit_depth=8;
            image->depth=8;
          }
      }
#endif
    ping_info->color_type=PNG_COLOR_TYPE_RGB;
    if ((image->x_resolution != 0) && (image->y_resolution != 0) &&
        (!image_info->adjoin || !equal_physs))
      {
        ping_info->valid|=PNG_INFO_pHYs;
        ping_info->phys_unit_type=PNG_RESOLUTION_UNKNOWN;
        ping_info->x_pixels_per_unit=(png_uint_32) image->x_resolution;
        ping_info->y_pixels_per_unit=(png_uint_32) image->y_resolution;
        if (image->units == PixelsPerInchResolution)
          {
            ping_info->phys_unit_type=PNG_RESOLUTION_METER;
            ping_info->x_pixels_per_unit=(png_uint_32)
              (100.0*image->x_resolution/2.54);
            ping_info->y_pixels_per_unit=(png_uint_32)
              (100.0*image->y_resolution/2.54);
          }
        if (image->units == PixelsPerCentimeterResolution)
          {
            ping_info->phys_unit_type=PNG_RESOLUTION_METER;
            ping_info->x_pixels_per_unit=(png_uint_32)
              (100.0*image->x_resolution);
            ping_info->y_pixels_per_unit=(png_uint_32)
              (100.0*image->y_resolution);
          }
      }
    if (!image_info->adjoin || !equal_backgrounds)
      {
        ping_info->valid|=PNG_INFO_bKGD;
        ping_info->background.red=
          (unsigned short)DownScale(image->background_color.red);
        ping_info->background.green=
          (unsigned short)DownScale(image->background_color.green);
        ping_info->background.blue=
          (unsigned short)DownScale(image->background_color.blue);
        ping_info->background.gray=
          (unsigned short)DownScale(Intensity(image->background_color));
        ping_info->background.index=ping_info->background.gray;
      }
    /*
      Select the color type.
    */
    matte=image->matte;
    if (matte)
      {
        ping_info->color_type=PNG_COLOR_TYPE_GRAY_ALPHA;
        p=image->pixels;
        for (i=0 ; i < (int) image->packets; i++)
        {
          if (!IsGray(*p))
            {
              ping_info->color_type=PNG_COLOR_TYPE_RGB_ALPHA;
              break;
            }
          p++;
        }
        /*
          Determine if there is any transparent color.
        */
        p=image->pixels;
        for (i=0; (p->index == Opaque) && (i < (int) (image->packets-1)); i++)
          p++;
        if (p->index != Opaque)
          {
            ping_info->valid|=PNG_INFO_tRNS;
            ping_info->trans_values.red=p->red;
            ping_info->trans_values.green=p->green;
            ping_info->trans_values.blue=p->blue;
            ping_info->trans_values.gray=(unsigned short) Intensity(*p);
            ping_info->trans_values.index=(unsigned short) DownScale(p->index);
          }
        else
          { 
            /*
              No transparent pixels are present.  Changes 4 or 6 to 0 or 2.
            */
            if (image_info->verbose)
              printf("There are no transparent pixels.\n");
            image->matte=False;
            ping_info->color_type&=0x03;
          }
        if (ping_info->valid & PNG_INFO_tRNS)
          {
            /*
              Determine if there is one and only one transparent color
              and if so if it is fully transparent.
            */
            p=image->pixels;
            for (i=0; i < (int) image->packets; i++)
            {
              if (p->index != Opaque)
                {
                  if (!ColorMatch(ping_info->trans_values,*p,0))
                    {
                      ping_info->valid&=(~PNG_INFO_tRNS);
                      if (image_info->verbose)
                        printf("There are two or more transparent colors.\n");
                      break;
                    }
                  if (p->index)
                    {
                      ping_info->valid&=(~PNG_INFO_tRNS);
                      if (image_info->verbose)
                        printf("A semitransparent color is present.\n");
                    }
                }
               else
                {
                  if (ColorMatch(ping_info->trans_values,*p,0))
                    {
                      /* Can't use RGB + tRNS */
                      ping_info->valid&=(~PNG_INFO_tRNS);
                      if (image_info->verbose)
                        printf("A color is both transparent and opaque.\n");
                      break;
                    }
                }
              p++;
            }
          }
        if (ping_info->valid & PNG_INFO_tRNS)
          {
            matte=False;
            ping_info->color_type &= 0x03;  /* changes 4 or 6 to 0 or 2 */
            if (save_image_depth == 16 && image->depth == 8)
              {
                if(image_info->verbose)
                  printf("reducing trans_values to 8-bit\n");
                ping_info->trans_values.red&=0xff;
                ping_info->trans_values.green&=0xff;
                ping_info->trans_values.blue&=0xff;
                ping_info->trans_values.gray&=0xff;
              }
          }
      }
    matte=image->matte;
    if (ping_info->valid & PNG_INFO_tRNS)
      image->matte=False;
    if (IsGrayImage(image))
      ping_info->color_type=PNG_COLOR_TYPE_GRAY;
    else
      if (image->depth <= 8 && IsPseudoClass(image))
        {
          /*
            Set image palette.
          */
          ping_info->color_type=PNG_COLOR_TYPE_PALETTE;
          ping_info->valid|=PNG_INFO_PLTE;
          if (have_write_global_plte)
            {
              if (image_info->verbose)
                printf("writing empty PLTE chunk\n");
              ping_info->num_palette=0;
            }
          else
            {
              ping_info->num_palette=image->colors;
              if (image_info->verbose)
                printf("Allocating memory for palette\n");
              ping_info->palette=(png_color *)
                AllocateMemory(image->colors*sizeof(png_color));
              if (ping_info->palette == (png_color *) NULL)
                WriterExit(ResourceLimitWarning,"Memory allocation failed",
                  image);
              for (i=0; i < (int) image->colors; i++)
              {
                ping_info->palette[i].red=
                  (unsigned short) DownScale(image->colormap[i].red);
                ping_info->palette[i].green=
                  (unsigned short) DownScale(image->colormap[i].green);
                ping_info->palette[i].blue=
                  (unsigned short) DownScale(image->colormap[i].blue);
              }
            }
          ping_info->bit_depth=1;
          while ((1 << ping_info->bit_depth) < (int) image->colors)
            ping_info->bit_depth<<=1;
          if (ping_info->valid & PNG_INFO_tRNS)
            {
              if (save_image_depth == 16 && image->depth == 8)
                {
                  if(image_info->verbose)
                    printf("re-expanding trans_values to 16-bit\n");
                  ping_info->trans_values.red*=0x0101;
                  ping_info->trans_values.green*=0x0101;
                  ping_info->trans_values.blue*=0x0101;
                  ping_info->trans_values.gray*=0x0101;
                }
              /*
                Identify which colormap entry is transparent.
              */
              if (image_info->verbose)
                printf("Allocating memory for trans\n");
              ping_info->trans=(unsigned char *)
                AllocateMemory(image->colors*sizeof(unsigned char));
              if (ping_info->trans == (unsigned char *) NULL)
                WriterExit(ResourceLimitWarning,"Memory allocation failed",
                  image);
              for (i=0; i < (int) image->colors; i++)
              {
                ping_info->trans[i]=DownScale(Opaque);
                if (ColorMatch(ping_info->trans_values,image->colormap[i],0))
                  {
                    ping_info->trans[i]=ping_info->trans_values.index;
                    break;
                  }
              }
              ping_info->num_trans=i+1;
              if (image_info->verbose)
                printf("transparent index = %d of %d\n",i, image->colors);
            }
          /*
            Identify which colormap entry is the background color.
          */
          for (i=0; i < (int) (image->colors-1); i++)
          {
            if (ColorMatch(ping_info->background,image->colormap[i],0))
              break;
          }
          if (image_info->verbose)
            printf("background index = %d of %d\n",i, image->colors);
          ping_info->background.index=(unsigned short) i;
        }
    if (image_info->verbose)
      {
        if(image->colors)
          printf("image->colors = %d\n",image->colors);
        printf("ping_info->color_type = %d\n",ping_info->color_type);
      }
    image->matte=matte;
#if defined(PNG_WRITE_sRGB_SUPPORTED)
    if (!have_write_global_srgb &&
        ((image->rendering_intent != UndefinedIntent) ||
        image_info->colorspace==sRGBColorspace))
      {
        /*
          Note image rendering intent.
        */
        ping_info->valid|=PNG_INFO_sRGB;
        if (image->rendering_intent)
          ping_info->srgb_intent=(int) image->rendering_intent-1;
        else
          ping_info->srgb_intent=1;
        image->gamma=0.45455;
      }
    if (!image_info->adjoin || (!ping_info->valid&PNG_INFO_sRGB))
#endif
      {
        if (!have_write_global_gama && image->gamma != 0.0)
          {
            /*
              Note image gamma.
              To do: check for cHRM+gAMA == sRGB, and write sRGB instead. 
            */
            ping_info->valid|=PNG_INFO_gAMA;
            ping_info->gamma=image->gamma;
          }
        if (!have_write_global_chrm && image->chromaticity.white_point.x != 0.0)
          {
            /*
              Note image chromaticity.
              To do: check for cHRM+gAMA == sRGB, and write sRGB instead. 
            */
            ping_info->valid|=PNG_INFO_cHRM;
            ping_info->x_red=image->chromaticity.red_primary.x;
            ping_info->y_red=image->chromaticity.red_primary.y;
            ping_info->x_green=image->chromaticity.green_primary.x;
            ping_info->y_green=image->chromaticity.green_primary.y;
            ping_info->x_blue=image->chromaticity.blue_primary.x;
            ping_info->y_blue=image->chromaticity.blue_primary.y;
            ping_info->x_white=image->chromaticity.white_point.x;
            ping_info->y_white=image->chromaticity.white_point.y;
         }
      }
    ping_info->interlace_type=image_info->interlace != NoInterlace;
    /*
      Initialize compression level and filtering.
    */
    png_set_compression_level(ping,Min(image_info->quality/10,9));
    if ((image_info->quality % 10) > 5)
      png_set_filter(ping,PNG_FILTER_TYPE_BASE,PNG_ALL_FILTERS);
    else
      if ((image_info->quality % 10) != 5)
        png_set_filter(ping,PNG_FILTER_TYPE_BASE,image_info->quality % 10);
      else
        if ((ping_info->color_type == PNG_COLOR_TYPE_GRAY) ||
            (ping_info->color_type == PNG_COLOR_TYPE_PALETTE) ||
            (image_info->quality < 50))
          png_set_filter(ping,PNG_FILTER_TYPE_BASE,PNG_NO_FILTERS);
        else
          png_set_filter(ping,PNG_FILTER_TYPE_BASE,PNG_ALL_FILTERS);
    if (need_fram && image_info->adjoin && ((image->delay != delay) ||
        (framing_mode != old_framing_mode)))
      {
        if (image->delay == delay)
          {
            /*
              Write a MNG FRAM chunk with the new framing mode.
            */
            MSBFirstWriteLong(image,1L);  /* data length = 1 */
            PNGType(chunk,mng_FRAM);
            chunk[4]=framing_mode;
            (void) WriteBlob(image,5,(char *) chunk);
            MSBFirstWriteLong(image,crc32(0,chunk,5));
          }
        else
          {
            /*
              Write a MNG FRAM chunk with the delay.
            */
            MSBFirstWriteLong(image,10L);  /* data length = 10 */
            PNGType(chunk,mng_FRAM);
            chunk[4]=framing_mode;
            chunk[5]=0;  /* frame name separator (no name) */
            chunk[6]=2;  /* flag for changing default delay */
            chunk[7]=0;  /* flag for changing frame timeout */
            chunk[8]=0;  /* flag for changing frame clipping */
            chunk[9]=0;  /* flag for changing frame sync_id */
            PNGLong(chunk+10,(png_uint_32)
              ((ticks_per_second*image->delay)/100));
            (void) WriteBlob(image,14,(char *) chunk);
            MSBFirstWriteLong(image,crc32(0,chunk,14));
            delay=image->delay;
          }
        old_framing_mode=framing_mode;
      }

    if (image_info->adjoin)
      png_set_sig_bytes(ping,8);
    png_write_info(ping,ping_info);
    png_set_packing(ping);
    /*
      Allocate memory.
    */
    rowbytes=image->columns;
    if (image->depth <= 8)
      {
        if (IsGrayImage(image))
          rowbytes*=(matte ? 2 : 1);
        else
          if(!IsPseudoClass(image))
            rowbytes*=(matte ? 4 : 3);
      }
    else
      {
        if (IsGrayImage(image))
          rowbytes*=(matte ? 4 : 2);
        else
          rowbytes*=(matte ? 8 : 6);
      }
    png_pixels=(unsigned char *)
      AllocateMemory(rowbytes*image->rows*sizeof(Quantum));
    scanlines=(unsigned char **)
      AllocateMemory(image->rows*sizeof(unsigned char *));
    if ((png_pixels == (unsigned char *) NULL) ||
        (scanlines == (unsigned char **) NULL))
      WriterExit(ResourceLimitWarning,"Memory allocation failed",image);
    /*
      Initialize image scanlines.
    */
    for (i=0; i < (int) image->rows; i++)
      scanlines[i]=png_pixels+(rowbytes*i);
    x=0;
    y=0;
    p=image->pixels;
    q=scanlines[y];
    if (IsMonochromeImage(image))
      {
        register unsigned char
          polarity;

        /*
          Convert PseudoClass image to a PNG monochrome image.
        */
        polarity=Intensity(image->colormap[0]) < (MaxRGB >> 1);
        if (image->colors == 2)
          polarity=
            Intensity(image->colormap[1]) > Intensity(image->colormap[0]);
        for (i=0; i < (int) image->packets; i++)
        {
          for (j=0; j <= ((int) p->length); j++)
          {
            WriteQuantum(p->index == polarity ? 1 : 0,q);
            x++;
            if (x == (int) image->columns)
              {
                x=0;
                y++;
                q=scanlines[y];
              }
          }
          p++;
        }
      }
    else
      if (IsGrayImage(image))
        {
          if (image_info->verbose)
            {
              printf("Writing GrayImage, QuantumDepth=%d and image->depth=%d\n",
                QuantumDepth,image->depth);
              printf("columns=%d, rowbytes=%d\n",image->columns,rowbytes);
            }
          for (i=0; i < (int) image->packets; i++)
          {
            for (j=0; j <= ((int) p->length); j++)
            {
              WriteQuantum(Intensity(*p),q);
              x++;
              if (x == (int) image->columns)
                {
                  x=0;
                  y++;
                  q=scanlines[y];
                }
            }
            p++;
          }
        }
      else
        {
          if (image_info->verbose)
            {
               printf("Writing image, QuantumDepth=%d and image->depth=%d\n",
                 QuantumDepth,image->depth);
               printf("columns=%d, rowbytes=%d\n",image->columns,
                 rowbytes);
             }
          if (image->depth > 8 || !IsPseudoClass(image))
            for (i=0; i < (int) image->packets; i++)
            {
              for (j=0; j <= ((int) p->length); j++)
              {
                WriteQuantum(p->red,q);
                if (ping_info->color_type != PNG_COLOR_TYPE_GRAY_ALPHA)
                  {
                    WriteQuantum(p->green,q);
                    WriteQuantum(p->blue,q);
                  }
                if (matte)
                  WriteQuantum(p->index,q);
                x++;
                if (x == (int) image->columns)
                  {
                    x=0;
                    y++;
                    if (y < (int) image->rows)
                      q=scanlines[y];
                  }
              }
              p++;
            }
        else
          for (i=0; i < (int) image->packets; i++)
          {
            for (j=0; j <= ((int) p->length); j++)
            {
              if (ping_info->color_type == PNG_COLOR_TYPE_GRAY)
                *q++=p->red;
              else
                *q++=p->index;
              x++;
              if (x == (int) image->columns)
                {
                  x=0;
                  y++;
                  if (y < (int) image->rows)
                    q=scanlines[y];
                }
            }
            p++;
          }
       }
    png_write_image(ping,scanlines);
    /*
      Generate text chunks.
    */
    ping_info->num_text=0;
    ping_info->text=(png_text *) AllocateMemory(256*sizeof(png_text));
    if (ping_info->text == (png_text *) NULL)
      WriterExit(ResourceLimitWarning,"Memory allocation failed",image);
    /* Write a Software tEXt chunk only in the first PNG datastream */
    if (image->scene == 0)
    WriteTextChunk(image_info,ping_info,"Software",MagickVersion);
    if (!image_info->adjoin)
      {
        SignatureImage(image);
        if (image->signature != (char *) NULL)
            WriteTextChunk(image_info,ping_info,"Signature",image->signature);
        if (image->delay != 0)
          {
            char
              delay[MaxTextExtent];

            FormatString(delay,"%u",image->delay);
            WriteTextChunk(image_info,ping_info,"Delay",delay);
          }
        if (image->scene != 0)
          {
            char
              scene[MaxTextExtent];

            FormatString(scene,"%u",image->scene);
            WriteTextChunk(image_info,ping_info,"Scene",scene);
          }
        if (image->page != (char *) NULL)
            WriteTextChunk(image_info,ping_info,"Page",image->page);
      }
    if (image->label != (char *) NULL)
      WriteTextChunk(image_info,ping_info,"Title",image->label);
    if (image->montage != (char *) NULL)
      WriteTextChunk(image_info,ping_info,"Montage",image->montage);
    if (image->directory != (char *) NULL)
      WriteTextChunk(image_info,ping_info,"Directory",image->directory);
    if (image->comments != (char *) NULL)
      WriteTextChunk(image_info,ping_info,"Comment",image->comments);
    png_write_end(ping,ping_info);
    if (need_fram && image->dispose == 2)
      {
        if (page_info.x || page_info.y ||
            (ping_info->width != page_info.width) ||
            (ping_info->height != page_info.height))
          {
            /*
              Write FRAM 4 with clipping boundaries followed by FRAM 1.
            */
            MSBFirstWriteLong(image,27L);  /* data length = 27 */
            PNGType(chunk,mng_FRAM);
            chunk[4]=4;
            chunk[5]=0;  /* frame name separator (no name) */
            chunk[6]=1;  /* flag for changing delay, for next frame only */
            chunk[7]=0;  /* flag for changing frame timeout */
            chunk[8]=1;  /* flag for changing frame clipping for next frame */
            chunk[9]=0;  /* flag for changing frame sync_id */
            PNGLong(chunk+10,(png_uint_32) (0L)); /* temporary 0 delay */
            chunk[14]=0; /* clipping boundaries delta type */
            PNGLong(chunk+15,(png_uint_32) (page_info.x)); /* left cb */
            PNGLong(chunk+19,(png_uint_32) (page_info.x + ping_info->width));
            PNGLong(chunk+23,(png_uint_32) (page_info.y)); /* top cb */
            PNGLong(chunk+27,(png_uint_32) (page_info.y + ping_info->height));
            (void) WriteBlob(image,31,(char *) chunk);
            MSBFirstWriteLong(image,crc32(0,chunk,31));
            old_framing_mode=4;
            framing_mode=1;
          }
        else
          framing_mode=3;
      }
    if (need_fram && (image->dispose == 3))
       MagickWarning(DelegateWarning,
         "Cannot convert GIF with disposal method 3 to MNG-LC",(char *) NULL);
    image->depth=save_image_depth;
    /*
      Free PNG resources.
    */
    if (ping_info->valid & PNG_INFO_PLTE)
      FreeMemory((char *) ping_info->palette);
    png_destroy_write_struct(&ping,&ping_info);
    FreeMemory((char *) scanlines);
    FreeMemory((char *) png_pixels);
    if (image->next == (Image *) NULL)
      break;
    image->next->file=image->file;
    image=image->next;
  } while (image_info->adjoin);
  if (image_info->adjoin)
    while (image->previous != (Image *) NULL)
      image=image->previous;
  if (image_info->adjoin)
    {
      /*
        Write the MEND chunk.
      */
      MSBFirstWriteLong(image,0x00000000L);
      PNGType(chunk,mng_MEND);
      (void) WriteBlob(image,4,(char *) chunk);
      MSBFirstWriteLong(image,crc32(0,chunk,4));
    }
  /*
    Free memory.
  */
  CloseBlob(image);
  return(True);
}
#else
Export unsigned int WritePNGImage(const ImageInfo *image_info,Image *image)
{
  MagickWarning(MissingDelegateWarning,"PNG library is not available",
    image->filename);
  return(False);
}
#endif


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