

/* pngwrite.c - general routines to write a PNG file

 *

 * Last changed in libpng 1.2.15 January 5, 2007

 * For conditions of distribution and use, see copyright notice in png.h

 * Copyright (c) 1998-2007 Glenn Randers-Pehrson

 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)

 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)

 */



/* get internal access to png.h */

#define PNG_INTERNAL

#include "png.h"

#ifdef PNG_WRITE_SUPPORTED



/* Writes all the PNG information.  This is the suggested way to use the

 * library.  If you have a new chunk to add, make a function to write it,

 * and put it in the correct location here.  If you want the chunk written

 * after the image data, put it in png_write_end().  I strongly encourage

 * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing

 * the chunk, as that will keep the code from breaking if you want to just

 * write a plain PNG file.  If you have long comments, I suggest writing

 * them in png_write_end(), and compressing them.

 */

void PNGAPI

png_write_info_before_PLTE(png_structp png_ptr, png_infop info_ptr)

{

   png_debug(1, "in png_write_info_before_PLTE\n");

   if (png_ptr == NULL || info_ptr == NULL)

      return;

   if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))

   {

   png_write_sig(png_ptr); /* write PNG signature */

#if defined(PNG_MNG_FEATURES_SUPPORTED)

   if((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&(png_ptr->mng_features_permitted))

   {

      png_warning(png_ptr,"MNG features are not allowed in a PNG datastream");

      png_ptr->mng_features_permitted=0;

   }

#endif

   /* write IHDR information. */

   png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,

      info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,

      info_ptr->filter_type,

#if defined(PNG_WRITE_INTERLACING_SUPPORTED)

      info_ptr->interlace_type);

#else

      0);

#endif

   /* the rest of these check to see if the valid field has the appropriate

      flag set, and if it does, writes the chunk. */

#if defined(PNG_WRITE_gAMA_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_gAMA)

   {

#  ifdef PNG_FLOATING_POINT_SUPPORTED

      png_write_gAMA(png_ptr, info_ptr->gamma);

#else

#ifdef PNG_FIXED_POINT_SUPPORTED

      png_write_gAMA_fixed(png_ptr, info_ptr->int_gamma);

#  endif

#endif

   }

#endif

#if defined(PNG_WRITE_sRGB_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_sRGB)

      png_write_sRGB(png_ptr, (int)info_ptr->srgb_intent);

#endif

#if defined(PNG_WRITE_iCCP_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_iCCP)

      png_write_iCCP(png_ptr, info_ptr->iccp_name, PNG_COMPRESSION_TYPE_BASE,

                     info_ptr->iccp_profile, (int)info_ptr->iccp_proflen);

#endif

#if defined(PNG_WRITE_sBIT_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_sBIT)

      png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);

#endif

#if defined(PNG_WRITE_cHRM_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_cHRM)

   {

#ifdef PNG_FLOATING_POINT_SUPPORTED

      png_write_cHRM(png_ptr,

         info_ptr->x_white, info_ptr->y_white,

         info_ptr->x_red, info_ptr->y_red,

         info_ptr->x_green, info_ptr->y_green,

         info_ptr->x_blue, info_ptr->y_blue);

#else

#  ifdef PNG_FIXED_POINT_SUPPORTED

      png_write_cHRM_fixed(png_ptr,

         info_ptr->int_x_white, info_ptr->int_y_white,

         info_ptr->int_x_red, info_ptr->int_y_red,

         info_ptr->int_x_green, info_ptr->int_y_green,

         info_ptr->int_x_blue, info_ptr->int_y_blue);

#  endif

#endif

   }

#endif

#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)

   if (info_ptr->unknown_chunks_num)

   {

       png_unknown_chunk *up;



       png_debug(5, "writing extra chunks\n");



       for (up = info_ptr->unknown_chunks;

            up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;

            up++)

       {

         int keep=png_handle_as_unknown(png_ptr, up->name);

         if (keep != PNG_HANDLE_CHUNK_NEVER &&

            up->location && !(up->location & PNG_HAVE_PLTE) &&

            !(up->location & PNG_HAVE_IDAT) &&

            ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||

            (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))

         {

            png_write_chunk(png_ptr, up->name, up->data, up->size);

         }

       }

   }

#endif

      png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;

   }

}



void PNGAPI

png_write_info(png_structp png_ptr, png_infop info_ptr)

{

#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)

   int i;

#endif



   png_debug(1, "in png_write_info\n");



   if (png_ptr == NULL || info_ptr == NULL)

      return;



   png_write_info_before_PLTE(png_ptr, info_ptr);



   if (info_ptr->valid & PNG_INFO_PLTE)

      png_write_PLTE(png_ptr, info_ptr->palette,

         (png_uint_32)info_ptr->num_palette);

   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)

      png_error(png_ptr, "Valid palette required for paletted images");



#if defined(PNG_WRITE_tRNS_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_tRNS)

      {

#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)

         /* invert the alpha channel (in tRNS) */

         if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&

            info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)

         {

            int j;

            for (j=0; j<(int)info_ptr->num_trans; j++)

               info_ptr->trans[j] = (png_byte)(255 - info_ptr->trans[j]);

         }

#endif

      png_write_tRNS(png_ptr, info_ptr->trans, &(info_ptr->trans_values),

         info_ptr->num_trans, info_ptr->color_type);

      }

#endif

#if defined(PNG_WRITE_bKGD_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_bKGD)

      png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);

#endif

#if defined(PNG_WRITE_hIST_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_hIST)

      png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);

#endif

#if defined(PNG_WRITE_oFFs_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_oFFs)

      png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,

         info_ptr->offset_unit_type);

#endif

#if defined(PNG_WRITE_pCAL_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_pCAL)

      png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,

         info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,

         info_ptr->pcal_units, info_ptr->pcal_params);

#endif

#if defined(PNG_WRITE_sCAL_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_sCAL)

#if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)

      png_write_sCAL(png_ptr, (int)info_ptr->scal_unit,

          info_ptr->scal_pixel_width, info_ptr->scal_pixel_height);

#else

#ifdef PNG_FIXED_POINT_SUPPORTED

      png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,

          info_ptr->scal_s_width, info_ptr->scal_s_height);

#else

      png_warning(png_ptr,

          "png_write_sCAL not supported; sCAL chunk not written.");

#endif

#endif

#endif

#if defined(PNG_WRITE_pHYs_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_pHYs)

      png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,

         info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);

#endif

#if defined(PNG_WRITE_tIME_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_tIME)

   {

      png_write_tIME(png_ptr, &(info_ptr->mod_time));

      png_ptr->mode |= PNG_WROTE_tIME;

   }

#endif

#if defined(PNG_WRITE_sPLT_SUPPORTED)

   if (info_ptr->valid & PNG_INFO_sPLT)

     for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)

       png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);

#endif

#if defined(PNG_WRITE_TEXT_SUPPORTED)

   /* Check to see if we need to write text chunks */

   for (i = 0; i < info_ptr->num_text; i++)

   {

      png_debug2(2, "Writing header text chunk %d, type %d\n", i,

         info_ptr->text[i].compression);

      /* an internationalized chunk? */

      if (info_ptr->text[i].compression > 0)

      {

#if defined(PNG_WRITE_iTXt_SUPPORTED)

          /* write international chunk */

          png_write_iTXt(png_ptr,

                         info_ptr->text[i].compression,

                         info_ptr->text[i].key,

                         info_ptr->text[i].lang,

                         info_ptr->text[i].lang_key,

                         info_ptr->text[i].text);

#else

          png_warning(png_ptr, "Unable to write international text");

#endif

          /* Mark this chunk as written */

          info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;

      }

      /* If we want a compressed text chunk */

      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)

      {

#if defined(PNG_WRITE_zTXt_SUPPORTED)

         /* write compressed chunk */

         png_write_zTXt(png_ptr, info_ptr->text[i].key,

            info_ptr->text[i].text, 0,

            info_ptr->text[i].compression);

#else

         png_warning(png_ptr, "Unable to write compressed text");

#endif

         /* Mark this chunk as written */

         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;

      }

      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)

      {

#if defined(PNG_WRITE_tEXt_SUPPORTED)

         /* write uncompressed chunk */

         png_write_tEXt(png_ptr, info_ptr->text[i].key,

                         info_ptr->text[i].text,

                         0);

#else

         png_warning(png_ptr, "Unable to write uncompressed text");

#endif

         /* Mark this chunk as written */

         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;

      }

   }

#endif

#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)

   if (info_ptr->unknown_chunks_num)

   {

       png_unknown_chunk *up;



       png_debug(5, "writing extra chunks\n");



       for (up = info_ptr->unknown_chunks;

            up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;

            up++)

       {

         int keep=png_handle_as_unknown(png_ptr, up->name);

         if (keep != PNG_HANDLE_CHUNK_NEVER &&

            up->location && (up->location & PNG_HAVE_PLTE) &&

            !(up->location & PNG_HAVE_IDAT) &&

            ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||

            (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))

         {

            png_write_chunk(png_ptr, up->name, up->data, up->size);

         }

       }

   }

#endif

}



/* Writes the end of the PNG file.  If you don't want to write comments or

 * time information, you can pass NULL for info.  If you already wrote these

 * in png_write_info(), do not write them again here.  If you have long

 * comments, I suggest writing them here, and compressing them.

 */

void PNGAPI

png_write_end(png_structp png_ptr, png_infop info_ptr)

{

   png_debug(1, "in png_write_end\n");

   if (png_ptr == NULL)

      return;

   if (!(png_ptr->mode & PNG_HAVE_IDAT))

      png_error(png_ptr, "No IDATs written into file");



   /* see if user wants us to write information chunks */

   if (info_ptr != NULL)

   {

#if defined(PNG_WRITE_TEXT_SUPPORTED)

      int i; /* local index variable */

#endif

#if defined(PNG_WRITE_tIME_SUPPORTED)

      /* check to see if user has supplied a time chunk */

      if ((info_ptr->valid & PNG_INFO_tIME) &&

         !(png_ptr->mode & PNG_WROTE_tIME))

         png_write_tIME(png_ptr, &(info_ptr->mod_time));

#endif

#if defined(PNG_WRITE_TEXT_SUPPORTED)

      /* loop through comment chunks */

      for (i = 0; i < info_ptr->num_text; i++)

      {

         png_debug2(2, "Writing trailer text chunk %d, type %d\n", i,

            info_ptr->text[i].compression);

         /* an internationalized chunk? */

         if (info_ptr->text[i].compression > 0)

         {

#if defined(PNG_WRITE_iTXt_SUPPORTED)

             /* write international chunk */

             png_write_iTXt(png_ptr,

                         info_ptr->text[i].compression,

                         info_ptr->text[i].key,

                         info_ptr->text[i].lang,

                         info_ptr->text[i].lang_key,

                         info_ptr->text[i].text);

#else

             png_warning(png_ptr, "Unable to write international text");

#endif

             /* Mark this chunk as written */

             info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;

         }

         else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)

         {

#if defined(PNG_WRITE_zTXt_SUPPORTED)

            /* write compressed chunk */

            png_write_zTXt(png_ptr, info_ptr->text[i].key,

               info_ptr->text[i].text, 0,

               info_ptr->text[i].compression);

#else

            png_warning(png_ptr, "Unable to write compressed text");

#endif

            /* Mark this chunk as written */

            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;

         }

         else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)

         {

#if defined(PNG_WRITE_tEXt_SUPPORTED)

            /* write uncompressed chunk */

            png_write_tEXt(png_ptr, info_ptr->text[i].key,

               info_ptr->text[i].text, 0);

#else

            png_warning(png_ptr, "Unable to write uncompressed text");

#endif



            /* Mark this chunk as written */

            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;

         }

      }

#endif

#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)

   if (info_ptr->unknown_chunks_num)

   {

       png_unknown_chunk *up;



       png_debug(5, "writing extra chunks\n");



       for (up = info_ptr->unknown_chunks;

            up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;

            up++)

       {

         int keep=png_handle_as_unknown(png_ptr, up->name);

         if (keep != PNG_HANDLE_CHUNK_NEVER &&

            up->location && (up->location & PNG_AFTER_IDAT) &&

            ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||

            (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))

         {

            png_write_chunk(png_ptr, up->name, up->data, up->size);

         }

       }

   }

#endif

   }



   png_ptr->mode |= PNG_AFTER_IDAT;



   /* write end of PNG file */

   png_write_IEND(png_ptr);

#if 0

/* This flush, added in libpng-1.0.8,  causes some applications to crash

   because they do not set png_ptr->output_flush_fn */

   png_flush(png_ptr);

#endif

}



#if defined(PNG_WRITE_tIME_SUPPORTED)

#if !defined(_WIN32_WCE)

/* "time.h" functions are not supported on WindowsCE */

void PNGAPI

png_convert_from_struct_tm(png_timep ptime, struct tm FAR * ttime)

{

   png_debug(1, "in png_convert_from_struct_tm\n");

   ptime->year = (png_uint_16)(1900 + ttime->tm_year);

   ptime->month = (png_byte)(ttime->tm_mon + 1);

   ptime->day = (png_byte)ttime->tm_mday;

   ptime->hour = (png_byte)ttime->tm_hour;

   ptime->minute = (png_byte)ttime->tm_min;

   ptime->second = (png_byte)ttime->tm_sec;

}



void PNGAPI

png_convert_from_time_t(png_timep ptime, time_t ttime)

{

   struct tm *tbuf;



   png_debug(1, "in png_convert_from_time_t\n");

   tbuf = gmtime(&ttime);

   png_convert_from_struct_tm(ptime, tbuf);

}

#endif

#endif



/* Initialize png_ptr structure, and allocate any memory needed */

png_structp PNGAPI

png_create_write_struct(png_const_charp user_png_ver, png_voidp error_ptr,

   png_error_ptr error_fn, png_error_ptr warn_fn)

{

#ifdef PNG_USER_MEM_SUPPORTED

   return (png_create_write_struct_2(user_png_ver, error_ptr, error_fn,

      warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));

}



/* Alternate initialize png_ptr structure, and allocate any memory needed */

png_structp PNGAPI

png_create_write_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,

   png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,

   png_malloc_ptr malloc_fn, png_free_ptr free_fn)

{

#endif /* PNG_USER_MEM_SUPPORTED */

   png_structp png_ptr;

#ifdef PNG_SETJMP_SUPPORTED

#ifdef USE_FAR_KEYWORD

   jmp_buf jmpbuf;

#endif

#endif

   int i;

   png_debug(1, "in png_create_write_struct\n");

#ifdef PNG_USER_MEM_SUPPORTED

   png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,

      (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);

#else

   png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);

#endif /* PNG_USER_MEM_SUPPORTED */

   if (png_ptr == NULL)

      return (NULL);



#if !defined(PNG_1_0_X)

#ifdef PNG_ASSEMBLER_CODE_SUPPORTED

#ifdef PNG_MMX_CODE_SUPPORTED

   png_init_mmx_flags(png_ptr);   /* 1.2.0 addition */

#endif

#endif

#endif /* PNG_1_0_X */



   /* added at libpng-1.2.6 */

#ifdef PNG_SET_USER_LIMITS_SUPPORTED

   png_ptr->user_width_max=PNG_USER_WIDTH_MAX;

   png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;

#endif



#ifdef PNG_SETJMP_SUPPORTED

#ifdef USE_FAR_KEYWORD

   if (setjmp(jmpbuf))

#else

   if (setjmp(png_ptr->jmpbuf))

#endif

   {

      png_free(png_ptr, png_ptr->zbuf);

      png_ptr->zbuf=NULL;

      png_destroy_struct(png_ptr);

      return (NULL);

   }

#ifdef USE_FAR_KEYWORD

   png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));

#endif

#endif



#ifdef PNG_USER_MEM_SUPPORTED

   png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);

#endif /* PNG_USER_MEM_SUPPORTED */

   png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);



   i=0;

   do

   {

     if(user_png_ver[i] != png_libpng_ver[i])

        png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;

   } while (png_libpng_ver[i++]);



   if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)

   {

     /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so

      * we must recompile any applications that use any older library version.

      * For versions after libpng 1.0, we will be compatible, so we need

      * only check the first digit.

      */

     if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||

         (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||

         (user_png_ver[0] == '0' && user_png_ver[2] < '9'))

     {

#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)

        char msg[80];

        if (user_png_ver)

        {

          sprintf(msg, "Application was compiled with png.h from libpng-%.20s",

             user_png_ver);

          png_warning(png_ptr, msg);

        }

        sprintf(msg, "Application  is  running with png.c from libpng-%.20s",

           png_libpng_ver);

        png_warning(png_ptr, msg);

#endif

#ifdef PNG_ERROR_NUMBERS_SUPPORTED

        png_ptr->flags=0;

#endif

        png_error(png_ptr,

           "Incompatible libpng version in application and library");

     }

   }



   /* initialize zbuf - compression buffer */

   png_ptr->zbuf_size = PNG_ZBUF_SIZE;

   png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,

      (png_uint_32)png_ptr->zbuf_size);



   png_set_write_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL,

      png_flush_ptr_NULL);



#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)

   png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,

      1, png_doublep_NULL, png_doublep_NULL);

#endif



#ifdef PNG_SETJMP_SUPPORTED

/* Applications that neglect to set up their own setjmp() and then encounter

   a png_error() will longjmp here.  Since the jmpbuf is then meaningless we

   abort instead of returning. */

#ifdef USE_FAR_KEYWORD

   if (setjmp(jmpbuf))

      PNG_ABORT();

   png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));

#else

   if (setjmp(png_ptr->jmpbuf))

      PNG_ABORT();

#endif

#endif

   return (png_ptr);

}



/* Initialize png_ptr structure, and allocate any memory needed */

#if defined(PNG_1_0_X) || defined(PNG_1_2_X)

/* Deprecated. */

#undef png_write_init

void PNGAPI

png_write_init(png_structp png_ptr)

{

   /* We only come here via pre-1.0.7-compiled applications */

   png_write_init_2(png_ptr, "1.0.6 or earlier", 0, 0);

}



void PNGAPI

png_write_init_2(png_structp png_ptr, png_const_charp user_png_ver,

   png_size_t png_struct_size, png_size_t png_info_size)

{

   /* We only come here via pre-1.0.12-compiled applications */

   if(png_ptr == NULL) return;

#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)

   if(png_sizeof(png_struct) > png_struct_size ||

      png_sizeof(png_info) > png_info_size)

   {

      char msg[80];

      png_ptr->warning_fn=NULL;

      if (user_png_ver)

      {

        sprintf(msg, "Application was compiled with png.h from libpng-%.20s",

           user_png_ver);

        png_warning(png_ptr, msg);

      }

      sprintf(msg, "Application  is  running with png.c from libpng-%.20s",

         png_libpng_ver);

      png_warning(png_ptr, msg);

   }

#endif

   if(png_sizeof(png_struct) > png_struct_size)

     {

       png_ptr->error_fn=NULL;

#ifdef PNG_ERROR_NUMBERS_SUPPORTED

       png_ptr->flags=0;

#endif

       png_error(png_ptr,

       "The png struct allocated by the application for writing is too small.");

     }

   if(png_sizeof(png_info) > png_info_size)

     {

       png_ptr->error_fn=NULL;

#ifdef PNG_ERROR_NUMBERS_SUPPORTED

       png_ptr->flags=0;

#endif

       png_error(png_ptr,

       "The info struct allocated by the application for writing is too small.");

     }

   png_write_init_3(&png_ptr, user_png_ver, png_struct_size);

}

#endif /* PNG_1_0_X || PNG_1_2_X */





void PNGAPI

png_write_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,

   png_size_t png_struct_size)

{

   png_structp png_ptr=*ptr_ptr;

#ifdef PNG_SETJMP_SUPPORTED

   jmp_buf tmp_jmp; /* to save current jump buffer */

#endif



   int i = 0;



   if (png_ptr == NULL)

      return;



   do

   {

     if (user_png_ver[i] != png_libpng_ver[i])

     {

#ifdef PNG_LEGACY_SUPPORTED

       png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;

#else

       png_ptr->warning_fn=NULL;

       png_warning(png_ptr,

     "Application uses deprecated png_write_init() and should be recompiled.");

       break;

#endif

     }

   } while (png_libpng_ver[i++]);



   png_debug(1, "in png_write_init_3\n");



#ifdef PNG_SETJMP_SUPPORTED

   /* save jump buffer and error functions */

   png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));

#endif



   if (png_sizeof(png_struct) > png_struct_size)

     {

       png_destroy_struct(png_ptr);

       png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);

       *ptr_ptr = png_ptr;

     }



   /* reset all variables to 0 */

   png_memset(png_ptr, 0, png_sizeof (png_struct));



   /* added at libpng-1.2.6 */

#ifdef PNG_SET_USER_LIMITS_SUPPORTED

   png_ptr->user_width_max=PNG_USER_WIDTH_MAX;

   png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;

#endif



#if !defined(PNG_1_0_X)

#ifdef PNG_ASSEMBLER_CODE_SUPPORTED

#ifdef PNG_MMX_CODE_SUPPORTED

   png_init_mmx_flags(png_ptr);   /* 1.2.0 addition */

#endif

#endif

#endif /* PNG_1_0_X */



#ifdef PNG_SETJMP_SUPPORTED

   /* restore jump buffer */

   png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));

#endif



   png_set_write_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL,

      png_flush_ptr_NULL);



   /* initialize zbuf - compression buffer */

   png_ptr->zbuf_size = PNG_ZBUF_SIZE;

   png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,

      (png_uint_32)png_ptr->zbuf_size);



#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)

   png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,

      1, png_doublep_NULL, png_doublep_NULL);

#endif

}



/* Write a few rows of image data.  If the image is interlaced,

 * either you will have to write the 7 sub images, or, if you

 * have called png_set_interlace_handling(), you will have to

 * "write" the image seven times.

 */

void PNGAPI

png_write_rows(png_structp png_ptr, png_bytepp row,

   png_uint_32 num_rows)

{

   png_uint_32 i; /* row counter */

   png_bytepp rp; /* row pointer */



   png_debug(1, "in png_write_rows\n");



   if (png_ptr == NULL)

      return;



   /* loop through the rows */

   for (i = 0, rp = row; i < num_rows; i++, rp++)

   {

      png_write_row(png_ptr, *rp);

   }

}



/* Write the image.  You only need to call this function once, even

 * if you are writing an interlaced image.

 */

void PNGAPI

png_write_image(png_structp png_ptr, png_bytepp image)

{

   png_uint_32 i; /* row index */

   int pass, num_pass; /* pass variables */

   png_bytepp rp; /* points to current row */



   if (png_ptr == NULL)

      return;



   png_debug(1, "in png_write_image\n");

#if defined(PNG_WRITE_INTERLACING_SUPPORTED)

   /* intialize interlace handling.  If image is not interlaced,

      this will set pass to 1 */

   num_pass = png_set_interlace_handling(png_ptr);

#else

   num_pass = 1;

#endif

   /* loop through passes */

   for (pass = 0; pass < num_pass; pass++)

   {

      /* loop through image */

      for (i = 0, rp = image; i < png_ptr->height; i++, rp++)

      {

         png_write_row(png_ptr, *rp);

      }

   }

}



/* called by user to write a row of image data */

void PNGAPI

png_write_row(png_structp png_ptr, png_bytep row)

{

   if (png_ptr == NULL)

      return;

   png_debug2(1, "in png_write_row (row %ld, pass %d)\n",

      png_ptr->row_number, png_ptr->pass);



   /* initialize transformations and other stuff if first time */

   if (png_ptr->row_number == 0 && png_ptr->pass == 0)

   {

   /* make sure we wrote the header info */

   if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))

      png_error(png_ptr,

         "png_write_info was never called before png_write_row.");



   /* check for transforms that have been set but were defined out */

#if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)

   if (png_ptr->transformations & PNG_INVERT_MONO)

      png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined.");

#endif

#if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)

   if (png_ptr->transformations & PNG_FILLER)

      png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined.");

#endif

#if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && defined(PNG_READ_PACKSWAP_SUPPORTED)

   if (png_ptr->transformations & PNG_PACKSWAP)

      png_warning(png_ptr, "PNG_WRITE_PACKSWAP_SUPPORTED is not defined.");

#endif

#if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)

   if (png_ptr->transformations & PNG_PACK)

      png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined.");

#endif

#if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)

   if (png_ptr->transformations & PNG_SHIFT)

      png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined.");

#endif

#if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)

   if (png_ptr->transformations & PNG_BGR)

      png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined.");

#endif

#if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)

   if (png_ptr->transformations & PNG_SWAP_BYTES)

      png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined.");

#endif



      png_write_start_row(png_ptr);

   }



#if defined(PNG_WRITE_INTERLACING_SUPPORTED)

   /* if interlaced and not interested in row, return */

   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))

   {

      switch (png_ptr->pass)

      {

         case 0:

            if (png_ptr->row_number & 0x07)

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

         case 1:

            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

         case 2:

            if ((png_ptr->row_number & 0x07) != 4)

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

         case 3:

            if ((png_ptr->row_number & 0x03) || png_ptr->width < 3)

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

         case 4:

            if ((png_ptr->row_number & 0x03) != 2)

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

         case 5:

            if ((png_ptr->row_number & 0x01) || png_ptr->width < 2)

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

         case 6:

            if (!(png_ptr->row_number & 0x01))

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

      }

   }

#endif



   /* set up row info for transformations */

   png_ptr->row_info.color_type = png_ptr->color_type;

   png_ptr->row_info.width = png_ptr->usr_width;

   png_ptr->row_info.channels = png_ptr->usr_channels;

   png_ptr->row_info.bit_depth = png_ptr->usr_bit_depth;

   png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *

      png_ptr->row_info.channels);



   png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,

      png_ptr->row_info.width);



   png_debug1(3, "row_info->color_type = %d\n", png_ptr->row_info.color_type);

   png_debug1(3, "row_info->width = %lu\n", png_ptr->row_info.width);

   png_debug1(3, "row_info->channels = %d\n", png_ptr->row_info.channels);

   png_debug1(3, "row_info->bit_depth = %d\n", png_ptr->row_info.bit_depth);

   png_debug1(3, "row_info->pixel_depth = %d\n", png_ptr->row_info.pixel_depth);

   png_debug1(3, "row_info->rowbytes = %lu\n", png_ptr->row_info.rowbytes);



   /* Copy user's row into buffer, leaving room for filter byte. */

   png_memcpy_check(png_ptr, png_ptr->row_buf + 1, row,

      png_ptr->row_info.rowbytes);



#if defined(PNG_WRITE_INTERLACING_SUPPORTED)

   /* handle interlacing */

   if (png_ptr->interlaced && png_ptr->pass < 6 &&

      (png_ptr->transformations & PNG_INTERLACE))

   {

      png_do_write_interlace(&(png_ptr->row_info),

         png_ptr->row_buf + 1, png_ptr->pass);

      /* this should always get caught above, but still ... */

      if (!(png_ptr->row_info.width))

      {

         png_write_finish_row(png_ptr);

         return;

      }

   }

#endif



   /* handle other transformations */

   if (png_ptr->transformations)

      png_do_write_transformations(png_ptr);



#if defined(PNG_MNG_FEATURES_SUPPORTED)

   /* Write filter_method 64 (intrapixel differencing) only if

    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and

    * 2. Libpng did not write a PNG signature (this filter_method is only

    *    used in PNG datastreams that are embedded in MNG datastreams) and

    * 3. The application called png_permit_mng_features with a mask that

    *    included PNG_FLAG_MNG_FILTER_64 and

    * 4. The filter_method is 64 and

    * 5. The color_type is RGB or RGBA

    */

   if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&

      (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))

   {

      /* Intrapixel differencing */

      png_do_write_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);

   }

#endif



   /* Find a filter if necessary, filter the row and write it out. */

   png_write_find_filter(png_ptr, &(png_ptr->row_info));



   if (png_ptr->write_row_fn != NULL)

      (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);

}



#if defined(PNG_WRITE_FLUSH_SUPPORTED)

/* Set the automatic flush interval or 0 to turn flushing off */

void PNGAPI

png_set_flush(png_structp png_ptr, int nrows)

{

   png_debug(1, "in png_set_flush\n");

   if (png_ptr == NULL)

      return;

   png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);

}



/* flush the current output buffers now */

void PNGAPI

png_write_flush(png_structp png_ptr)

{

   int wrote_IDAT;



   png_debug(1, "in png_write_flush\n");

   if (png_ptr == NULL)

      return;

   /* We have already written out all of the data */

   if (png_ptr->row_number >= png_ptr->num_rows)

     return;



   do

   {

      int ret;



      /* compress the data */

      ret = deflate(&png_ptr->zstream, Z_SYNC_FLUSH);

      wrote_IDAT = 0;



      /* check for compression errors */

      if (ret != Z_OK)

      {

         if (png_ptr->zstream.msg != NULL)

            png_error(png_ptr, png_ptr->zstream.msg);

         else

            png_error(png_ptr, "zlib error");

      }



      if (!(png_ptr->zstream.avail_out))

      {

         /* write the IDAT and reset the zlib output buffer */

         png_write_IDAT(png_ptr, png_ptr->zbuf,

                        png_ptr->zbuf_size);

         png_ptr->zstream.next_out = png_ptr->zbuf;

         png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;

         wrote_IDAT = 1;

      }

   } while(wrote_IDAT == 1);



   /* If there is any data left to be output, write it into a new IDAT */

   if (png_ptr->zbuf_size != png_ptr->zstream.avail_out)

   {

      /* write the IDAT and reset the zlib output buffer */

      png_write_IDAT(png_ptr, png_ptr->zbuf,

                     png_ptr->zbuf_size - png_ptr->zstream.avail_out);

      png_ptr->zstream.next_out = png_ptr->zbuf;

      png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;

   }

   png_ptr->flush_rows = 0;

   png_flush(png_ptr);

}

#endif /* PNG_WRITE_FLUSH_SUPPORTED */



/* free all memory used by the write */

void PNGAPI

png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)

{

   png_structp png_ptr = NULL;

   png_infop info_ptr = NULL;

#ifdef PNG_USER_MEM_SUPPORTED

   png_free_ptr free_fn = NULL;

   png_voidp mem_ptr = NULL;

#endif



   png_debug(1, "in png_destroy_write_struct\n");

   if (png_ptr_ptr != NULL)

   {

      png_ptr = *png_ptr_ptr;

#ifdef PNG_USER_MEM_SUPPORTED

      free_fn = png_ptr->free_fn;

      mem_ptr = png_ptr->mem_ptr;

#endif

   }



   if (info_ptr_ptr != NULL)

      info_ptr = *info_ptr_ptr;



   if (info_ptr != NULL)

   {

      png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);



#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)

      if (png_ptr->num_chunk_list)

      {

         png_free(png_ptr, png_ptr->chunk_list);

         png_ptr->chunk_list=NULL;

         png_ptr->num_chunk_list=0;

      }

#endif



#ifdef PNG_USER_MEM_SUPPORTED

      png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,

         (png_voidp)mem_ptr);

#else

      png_destroy_struct((png_voidp)info_ptr);

#endif

      *info_ptr_ptr = NULL;

   }



   if (png_ptr != NULL)

   {

      png_write_destroy(png_ptr);

#ifdef PNG_USER_MEM_SUPPORTED

      png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,

         (png_voidp)mem_ptr);

#else

      png_destroy_struct((png_voidp)png_ptr);

#endif

      *png_ptr_ptr = NULL;

   }

}





/* Free any memory used in png_ptr struct (old method) */

void /* PRIVATE */

png_write_destroy(png_structp png_ptr)

{

#ifdef PNG_SETJMP_SUPPORTED

   jmp_buf tmp_jmp; /* save jump buffer */

#endif

   png_error_ptr error_fn;

   png_error_ptr warning_fn;

   png_voidp error_ptr;

#ifdef PNG_USER_MEM_SUPPORTED

   png_free_ptr free_fn;

#endif



   png_debug(1, "in png_write_destroy\n");

   /* free any memory zlib uses */

   deflateEnd(&png_ptr->zstream);



   /* free our memory.  png_free checks NULL for us. */

   png_free(png_ptr, png_ptr->zbuf);

   png_free(png_ptr, png_ptr->row_buf);

   png_free(png_ptr, png_ptr->prev_row);

   png_free(png_ptr, png_ptr->sub_row);

   png_free(png_ptr, png_ptr->up_row);

   png_free(png_ptr, png_ptr->avg_row);

   png_free(png_ptr, png_ptr->paeth_row);



#if defined(PNG_TIME_RFC1123_SUPPORTED)

   png_free(png_ptr, png_ptr->time_buffer);

#endif



#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)

   png_free(png_ptr, png_ptr->prev_filters);

   png_free(png_ptr, png_ptr->filter_weights);

   png_free(png_ptr, png_ptr->inv_filter_weights);

   png_free(png_ptr, png_ptr->filter_costs);

   png_free(png_ptr, png_ptr->inv_filter_costs);

#endif



#ifdef PNG_SETJMP_SUPPORTED

   /* reset structure */

   png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));

#endif



   error_fn = png_ptr->error_fn;

   warning_fn = png_ptr->warning_fn;

   error_ptr = png_ptr->error_ptr;

#ifdef PNG_USER_MEM_SUPPORTED

   free_fn = png_ptr->free_fn;

#endif



   png_memset(png_ptr, 0, png_sizeof (png_struct));



   png_ptr->error_fn = error_fn;

   png_ptr->warning_fn = warning_fn;

   png_ptr->error_ptr = error_ptr;

#ifdef PNG_USER_MEM_SUPPORTED

   png_ptr->free_fn = free_fn;

#endif



#ifdef PNG_SETJMP_SUPPORTED

   png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));

#endif

}



/* Allow the application to select one or more row filters to use. */

void PNGAPI

png_set_filter(png_structp png_ptr, int method, int filters)

{

   png_debug(1, "in png_set_filter\n");

   if (png_ptr == NULL)

      return;

#if defined(PNG_MNG_FEATURES_SUPPORTED)

   if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&

      (method == PNG_INTRAPIXEL_DIFFERENCING))

         method = PNG_FILTER_TYPE_BASE;

#endif

   if (method == PNG_FILTER_TYPE_BASE)

   {

      switch (filters & (PNG_ALL_FILTERS | 0x07))

      {

         case 5:

         case 6:

         case 7: png_warning(png_ptr, "Unknown row filter for method 0");

         case PNG_FILTER_VALUE_NONE:  png_ptr->do_filter=PNG_FILTER_NONE; break;

         case PNG_FILTER_VALUE_SUB:   png_ptr->do_filter=PNG_FILTER_SUB;  break;

         case PNG_FILTER_VALUE_UP:    png_ptr->do_filter=PNG_FILTER_UP;   break;

         case PNG_FILTER_VALUE_AVG:   png_ptr->do_filter=PNG_FILTER_AVG;  break;

         case PNG_FILTER_VALUE_PAETH: png_ptr->do_filter=PNG_FILTER_PAETH;break;

         default: png_ptr->do_filter = (png_byte)filters; break;

      }



      /* If we have allocated the row_buf, this means we have already started

       * with the image and we should have allocated all of the filter buffers

       * that have been selected.  If prev_row isn't already allocated, then

       * it is too late to start using the filters that need it, since we

       * will be missing the data in the previous row.  If an application

       * wants to start and stop using particular filters during compression,

       * it should start out with all of the filters, and then add and

       * remove them after the start of compression.

       */

      if (png_ptr->row_buf != NULL)

      {

         if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)

         {

            png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,

              (png_ptr->rowbytes + 1));

            png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;

         }



         if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)

         {

            if (png_ptr->prev_row == NULL)

            {

               png_warning(png_ptr, "Can't add Up filter after starting");

               png_ptr->do_filter &= ~PNG_FILTER_UP;

            }

            else

            {

               png_ptr->up_row = (png_bytep)png_malloc(png_ptr,

                  (png_ptr->rowbytes + 1));

               png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;

            }

         }



         if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)

         {

            if (png_ptr->prev_row == NULL)

            {

               png_warning(png_ptr, "Can't add Average filter after starting");

               png_ptr->do_filter &= ~PNG_FILTER_AVG;

            }

            else

            {

               png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,

                  (png_ptr->rowbytes + 1));

               png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;

            }

         }



         if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&

             png_ptr->paeth_row == NULL)

         {

            if (png_ptr->prev_row == NULL)

            {

               png_warning(png_ptr, "Can't add Paeth filter after starting");

               png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);

            }

            else

            {

               png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,

                  (png_ptr->rowbytes + 1));

               png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;

            }

         }



         if (png_ptr->do_filter == PNG_NO_FILTERS)

            png_ptr->do_filter = PNG_FILTER_NONE;

      }

   }

   else

      png_error(png_ptr, "Unknown custom filter method");

}



/* This allows us to influence the way in which libpng chooses the "best"

 * filter for the current scanline.  While the "minimum-sum-of-absolute-

 * differences metric is relatively fast and effective, there is some

 * question as to whether it can be improved upon by trying to keep the

 * filtered data going to zlib more consistent, hopefully resulting in

 * better compression.

 */

#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)      /* GRR 970116 */

void PNGAPI

png_set_filter_heuristics(png_structp png_ptr, int heuristic_method,

   int num_weights, png_doublep filter_weights,

   png_doublep filter_costs)

{

   int i;



   png_debug(1, "in png_set_filter_heuristics\n");

   if (png_ptr == NULL)

      return;

   if (heuristic_method >= PNG_FILTER_HEURISTIC_LAST)

   {

      png_warning(png_ptr, "Unknown filter heuristic method");

      return;

   }



   if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT)

   {

      heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;

   }



   if (num_weights < 0 || filter_weights == NULL ||

      heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED)

   {

      num_weights = 0;

   }



   png_ptr->num_prev_filters = (png_byte)num_weights;

   png_ptr->heuristic_method = (png_byte)heuristic_method;



   if (num_weights > 0)

   {

      if (png_ptr->prev_filters == NULL)

      {

         png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr,

            (png_uint_32)(png_sizeof(png_byte) * num_weights));



         /* To make sure that the weighting starts out fairly */

         for (i = 0; i < num_weights; i++)

         {

            png_ptr->prev_filters[i] = 255;

         }

      }



      if (png_ptr->filter_weights == NULL)

      {

         png_ptr->filter_weights = (png_uint_16p)png_malloc(png_ptr,

            (png_uint_32)(png_sizeof(png_uint_16) * num_weights));



         png_ptr->inv_filter_weights = (png_uint_16p)png_malloc(png_ptr,

            (png_uint_32)(png_sizeof(png_uint_16) * num_weights));

         for (i = 0; i < num_weights; i++)

         {

            png_ptr->inv_filter_weights[i] =

            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;

         }

      }



      for (i = 0; i < num_weights; i++)

      {

         if (filter_weights[i] < 0.0)

         {

            png_ptr->inv_filter_weights[i] =

            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;

         }

         else

         {

            png_ptr->inv_filter_weights[i] =

               (png_uint_16)((double)PNG_WEIGHT_FACTOR*filter_weights[i]+0.5);

            png_ptr->filter_weights[i] =

               (png_uint_16)((double)PNG_WEIGHT_FACTOR/filter_weights[i]+0.5);

         }

      }

   }



   /* If, in the future, there are other filter methods, this would

    * need to be based on png_ptr->filter.

    */

   if (png_ptr->filter_costs == NULL)

   {

      png_ptr->filter_costs = (png_uint_16p)png_malloc(png_ptr,

         (png_uint_32)(png_sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));



      png_ptr->inv_filter_costs = (png_uint_16p)png_malloc(png_ptr,

         (png_uint_32)(png_sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));



      for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)

      {

         png_ptr->inv_filter_costs[i] =

         png_ptr->filter_costs[i] = PNG_COST_FACTOR;

      }

   }



   /* Here is where we set the relative costs of the different filters.  We

    * should take the desired compression level into account when setting

    * the costs, so that Paeth, for instance, has a high relative cost at low

    * compression levels, while it has a lower relative cost at higher

    * compression settings.  The filter types are in order of increasing

    * relative cost, so it would be possible to do this with an algorithm.

    */

   for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)

   {

      if (filter_costs == NULL || filter_costs[i] < 0.0)

      {

         png_ptr->inv_filter_costs[i] =

         png_ptr->filter_costs[i] = PNG_COST_FACTOR;

      }

      else if (filter_costs[i] >= 1.0)

      {

         png_ptr->inv_filter_costs[i] =

            (png_uint_16)((double)PNG_COST_FACTOR / filter_costs[i] + 0.5);

         png_ptr->filter_costs[i] =

            (png_uint_16)((double)PNG_COST_FACTOR * filter_costs[i] + 0.5);

      }

   }

}

#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */



void PNGAPI

png_set_compression_level(png_structp png_ptr, int level)

{

   png_debug(1, "in png_set_compression_level\n");

   if (png_ptr == NULL)

      return;

   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_LEVEL;

   png_ptr->zlib_level = level;

}



void PNGAPI

png_set_compression_mem_level(png_structp png_ptr, int mem_level)

{

   png_debug(1, "in png_set_compression_mem_level\n");

   if (png_ptr == NULL)

      return;

   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL;

   png_ptr->zlib_mem_level = mem_level;

}



void PNGAPI

png_set_compression_strategy(png_structp png_ptr, int strategy)

{

   png_debug(1, "in png_set_compression_strategy\n");

   if (png_ptr == NULL)

      return;

   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;

   png_ptr->zlib_strategy = strategy;

}



void PNGAPI

png_set_compression_window_bits(png_structp png_ptr, int window_bits)

{

   if (png_ptr == NULL)

      return;

   if (window_bits > 15)

      png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");

   else if (window_bits < 8)

      png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");

#ifndef WBITS_8_OK

   /* avoid libpng bug with 256-byte windows */

   if (window_bits == 8)

     {

       png_warning(png_ptr, "Compression window is being reset to 512");

       window_bits=9;

     }

#endif

   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS;

   png_ptr->zlib_window_bits = window_bits;

}



void PNGAPI

png_set_compression_method(png_structp png_ptr, int method)

{

   png_debug(1, "in png_set_compression_method\n");

   if (png_ptr == NULL)

      return;

   if (method != 8)

      png_warning(png_ptr, "Only compression method 8 is supported by PNG");

   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_METHOD;

   png_ptr->zlib_method = method;

}



void PNGAPI

png_set_write_status_fn(png_structp png_ptr, png_write_status_ptr write_row_fn)

{

   if (png_ptr == NULL)

      return;

   png_ptr->write_row_fn = write_row_fn;

}



#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)

void PNGAPI

png_set_write_user_transform_fn(png_structp png_ptr, png_user_transform_ptr

   write_user_transform_fn)

{

   png_debug(1, "in png_set_write_user_transform_fn\n");

   if (png_ptr == NULL)

      return;

   png_ptr->transformations |= PNG_USER_TRANSFORM;

   png_ptr->write_user_transform_fn = write_user_transform_fn;

}

#endif





#if defined(PNG_INFO_IMAGE_SUPPORTED)

void PNGAPI

png_write_png(png_structp png_ptr, png_infop info_ptr,

              int transforms, voidp params)

{

   if (png_ptr == NULL || info_ptr == NULL)

      return;

#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)

   /* invert the alpha channel from opacity to transparency */

   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)

       png_set_invert_alpha(png_ptr);

#endif



   /* Write the file header information. */

   png_write_info(png_ptr, info_ptr);



   /* ------ these transformations don't touch the info structure ------- */



#if defined(PNG_WRITE_INVERT_SUPPORTED)

   /* invert monochrome pixels */

   if (transforms & PNG_TRANSFORM_INVERT_MONO)

       png_set_invert_mono(png_ptr);

#endif



#if defined(PNG_WRITE_SHIFT_SUPPORTED)

   /* Shift the pixels up to a legal bit depth and fill in

    * as appropriate to correctly scale the image.

    */

   if ((transforms & PNG_TRANSFORM_SHIFT)

               && (info_ptr->valid & PNG_INFO_sBIT))

       png_set_shift(png_ptr, &info_ptr->sig_bit);

#endif



#if defined(PNG_WRITE_PACK_SUPPORTED)

   /* pack pixels into bytes */

   if (transforms & PNG_TRANSFORM_PACKING)

       png_set_packing(png_ptr);

#endif



#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)

   /* swap location of alpha bytes from ARGB to RGBA */

   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)

       png_set_swap_alpha(png_ptr);

#endif



#if defined(PNG_WRITE_FILLER_SUPPORTED)

   /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into

    * RGB (4 channels -> 3 channels). The second parameter is not used.

    */

   if (transforms & PNG_TRANSFORM_STRIP_FILLER)

       png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);

#endif



#if defined(PNG_WRITE_BGR_SUPPORTED)

   /* flip BGR pixels to RGB */

   if (transforms & PNG_TRANSFORM_BGR)

       png_set_bgr(png_ptr);

#endif



#if defined(PNG_WRITE_SWAP_SUPPORTED)

   /* swap bytes of 16-bit files to most significant byte first */

   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)

       png_set_swap(png_ptr);

#endif



#if defined(PNG_WRITE_PACKSWAP_SUPPORTED)

   /* swap bits of 1, 2, 4 bit packed pixel formats */

   if (transforms & PNG_TRANSFORM_PACKSWAP)

       png_set_packswap(png_ptr);

#endif



   /* ----------------------- end of transformations ------------------- */



   /* write the bits */

   if (info_ptr->valid & PNG_INFO_IDAT)

       png_write_image(png_ptr, info_ptr->row_pointers);



   /* It is REQUIRED to call this to finish writing the rest of the file */

   png_write_end(png_ptr, info_ptr);



   if(transforms == 0 || params == NULL)

      /* quiet compiler warnings */ return;

}

#endif

#endif /* PNG_WRITE_SUPPORTED */

