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 *

 * Last changed in libpng 1.6.2 [April 25, 2013]

 * Copyright (c) 1998-2013 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.)

 *

 * This code is released under the libpng license.

 * For conditions of distribution and use, see the disclaimer

 * and license in png.h

 */

#if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)

#  include 

#endif

/* Write out all the unknown chunks for the current given location */

static void

write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,

   unsigned int where)

{

   if (info_ptr->unknown_chunks_num)

   {

      png_const_unknown_chunkp up;

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

           ++up)

         if (up->location & where)

      {

         /* If per-chunk unknown chunk handling is enabled use it, otherwise

          * just write the chunks the application has set.

          */

#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED

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

          * matter of handling an ancillary unknown chunk.  In the read side

          * the default behavior is to discard it, in the code below the default

          * behavior is to write it.  Critical chunks are, however, only

          * written if explicitly listed or if the default is set to write all

          * unknown chunks.

          *

          * The default handling is also slightly weird - it is not possible to

          * stop the writing of all unsafe-to-copy chunks!

          *

          * TODO: REVIEW: this would seem to be a bug.

          */

         if (keep != PNG_HANDLE_CHUNK_NEVER &&

             ((up->name[3] & 0x20) /* safe-to-copy overrides everything */ ||

              keep == PNG_HANDLE_CHUNK_ALWAYS ||

              (keep == PNG_HANDLE_CHUNK_AS_DEFAULT &&

               png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS)))

#endif

         {

            /* TODO: review, what is wrong with a zero length unknown chunk? */

            if (up->size == 0)

               png_warning(png_ptr, "Writing zero-length unknown chunk");

         }

      }

   }

}

#endif /* PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED */

 * 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_structrp png_ptr, png_const_inforp info_ptr)

{

   png_debug(1, "in png_write_info_before_PLTE");

      return;

   {

   /* Write PNG signature */

   png_write_sig(png_ptr);

   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

   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,

#ifdef PNG_WRITE_INTERLACING_SUPPORTED

       info_ptr->interlace_type

#else

       0

      );

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

    *

    * 1.6.0: COLORSPACE support controls the writing of these chunks too, and

    * the chunks will be written if the WRITE routine is there and information

    * is available in the COLORSPACE.  (See png_colorspace_sync_info in png.c

    * for where the valid flags get set.)

    *

    * Under certain circumstances the colorspace can be invalidated without

    * syncing the info_struct 'valid' flags; this happens if libpng detects and

    * error and calls png_error while the color space is being set, yet the

    * application continues writing the PNG.  So check the 'invalid' flag here

    * too.

    */

#ifdef PNG_GAMMA_SUPPORTED

#  ifdef PNG_WRITE_gAMA_SUPPORTED

      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&

         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) &&

         (info_ptr->valid & PNG_INFO_gAMA))

         png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);

#  endif

#endif

   /* Write only one of sRGB or an ICC profile.  If a profile was supplied

    * and it matches one of the known sRGB ones issue a warning.

    */

#  ifdef PNG_WRITE_iCCP_SUPPORTED

      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&

         (info_ptr->valid & PNG_INFO_iCCP))

      {

#        ifdef PNG_WRITE_sRGB_SUPPORTED

            if (info_ptr->valid & PNG_INFO_sRGB)

               png_app_warning(png_ptr,

                  "profile matches sRGB but writing iCCP instead");

#        endif

            info_ptr->iccp_profile);

      }

#     ifdef PNG_WRITE_sRGB_SUPPORTED

         else

#     endif

#  endif

      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&

         (info_ptr->valid & PNG_INFO_sRGB))

         png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);

#  endif /* WRITE_sRGB */

#endif /* COLORSPACE */

   if (info_ptr->valid & PNG_INFO_sBIT)

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

#endif

#  ifdef PNG_WRITE_cHRM_SUPPORTED

      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&

         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) &&

         (info_ptr->valid & PNG_INFO_cHRM))

         png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);

#  endif

#endif

      write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);

#endif

   }

}

png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)

{

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

   int i;

#endif

      return;

      png_write_PLTE(png_ptr, info_ptr->palette,

          (png_uint_32)info_ptr->num_palette);

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

   if (info_ptr->valid & PNG_INFO_tRNS)

   {

#ifdef 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_alpha[j] =

               (png_byte)(255 - info_ptr->trans_alpha[j]);

      }

#endif

      png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),

          info_ptr->num_trans, info_ptr->color_type);

   }

#endif

#ifdef 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 (info_ptr->valid & PNG_INFO_hIST)

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

#endif

   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 (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 (info_ptr->valid & PNG_INFO_sCAL)

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

          info_ptr->scal_s_width, info_ptr->scal_s_height);

#endif /* sCAL */

   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 /* pHYs */

   if (info_ptr->valid & PNG_INFO_tIME)

   {

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

      png_ptr->mode |= PNG_WROTE_tIME;

   }

#endif /* tIME */

   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 /* sPLT */

   /* 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", i,

          info_ptr->text[i].compression);

      /* An internationalized chunk? */

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

      {

#ifdef 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)

      {

#ifdef 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;

      }

      {

#ifdef PNG_WRITE_tEXt_SUPPORTED

         /* Write uncompressed chunk */

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

             info_ptr->text[i].text,

             0);

         /* Mark this chunk as written */

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

#else

         /* Can't get here */

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

#endif

      }

   }

#endif /* tEXt */

   write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);

#endif

}

 * 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_structrp png_ptr, png_inforp info_ptr)

{

   png_debug(1, "in png_write_end");

      return;

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

   if (png_ptr->num_palette_max > png_ptr->num_palette)

      png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");

#endif

   if (info_ptr != NULL)

   {

#ifdef PNG_WRITE_TEXT_SUPPORTED

      int i; /* local index variable */

#endif

#ifdef 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));

#ifdef 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", i,

            info_ptr->text[i].compression);

         /* An internationalized chunk? */

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

         {

#ifdef 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;

         }

         {

#ifdef 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;

         }

         {

#ifdef 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

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

         }

      }

#endif

#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED

      write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);

#endif

   }

   png_write_IEND(png_ptr);

   /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,

    * and restored again in libpng-1.2.30, may cause some applications that

    * do not set png_ptr->output_flush_fn to crash.  If your application

    * experiences a problem, please try building libpng with

    * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to

    * png-mng-implement at lists.sf.net .

    */

#ifdef PNG_WRITE_FLUSH_SUPPORTED

#  ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED

   png_flush(png_ptr);

#  endif

#endif

}

void PNGAPI

png_convert_from_struct_tm(png_timep ptime, PNG_CONST struct tm * ttime)

{

   png_debug(1, "in png_convert_from_struct_tm");

   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;

}

png_convert_from_time_t(png_timep ptime, time_t ttime)

{

   struct tm *tbuf;

   png_convert_from_struct_tm(ptime, tbuf);

}

#endif

PNG_FUNCTION(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),PNG_ALLOCATED)

{

#ifndef PNG_USER_MEM_SUPPORTED

   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,

      error_fn, warn_fn, NULL, NULL, NULL);

#else

   return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,

       warn_fn, NULL, NULL, NULL);

}

PNG_FUNCTION(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),PNG_ALLOCATED)

{

   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,

      error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);

#endif /* PNG_USER_MEM_SUPPORTED */

   if (png_ptr != NULL)

   {

      /* Set the zlib control values to defaults; they can be overridden by the

       * application after the struct has been created.

       */

      png_ptr->zbuffer_size = PNG_ZBUF_SIZE;

       * pngwutil.c defaults it according to whether or not filters will be

       * used, and ignores this setting.

       */

      png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;

      png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;

      png_ptr->zlib_mem_level = 8;

      png_ptr->zlib_window_bits = 15;

      png_ptr->zlib_method = 8;

      png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;

      png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;

      png_ptr->zlib_text_mem_level = 8;

      png_ptr->zlib_text_window_bits = 15;

      png_ptr->zlib_text_method = 8;

#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */

       * but it may be appropriate for private builds that are testing

       * extensions not conformant to the current specification, or of

       * applications that must not fail to write at all costs!

       */

#ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED

      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;

      /* In stable builds only warn if an application error can be completely

       * handled.

       */

#endif

       * are errors during development.

       */

#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC

      png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;

#endif

       * do it itself) avoiding setting the default function if it is not

       * required.

       */

      png_set_write_fn(png_ptr, NULL, NULL, NULL);

   }

}

 * 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_structrp png_ptr, png_bytepp row,

    png_uint_32 num_rows)

{

   png_uint_32 i; /* row counter */

   png_bytepp rp; /* row pointer */

      return;

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

   {

      png_write_row(png_ptr, *rp);

   }

}

 * if you are writing an interlaced image.

 */

void PNGAPI

png_write_image(png_structrp png_ptr, png_bytepp image)

{

   png_uint_32 i; /* row index */

   int pass, num_pass; /* pass variables */

   png_bytepp rp; /* points to current row */

      return;

   /* Initialize 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);

      }

   }

}

void PNGAPI

png_write_row(png_structrp png_ptr, png_const_bytep row)

{

   /* 1.5.6: moved from png_struct to be a local structure: */

   png_row_info row_info;

      return;

      png_ptr->row_number, png_ptr->pass);

   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");

#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 (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 (png_ptr->transformations & PNG_PACK)

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

#endif

      if (png_ptr->transformations & PNG_SHIFT)

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

#endif

      if (png_ptr->transformations & PNG_BGR)

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

#endif

      if (png_ptr->transformations & PNG_SWAP_BYTES)

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

#endif

   }

   /* 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;

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

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

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

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

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

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

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

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

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

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

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

            {

               png_write_finish_row(png_ptr);

               return;

            }

            break;

            break;

      }

   }

#endif

   row_info.color_type = png_ptr->color_type;

   row_info.width = png_ptr->usr_width;

   row_info.channels = png_ptr->usr_channels;

   row_info.bit_depth = png_ptr->usr_bit_depth;

   row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);

   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);

   png_debug1(3, "row_info->width = %u", row_info.width);

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

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

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

   png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);

   memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);

   /* Handle interlacing */

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

       (png_ptr->transformations & PNG_INTERLACE))

   {

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

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

      if (!(row_info.width))

      {

         png_write_finish_row(png_ptr);

         return;

      }

   }

#endif

   /* Handle other transformations */

   if (png_ptr->transformations)

      png_do_write_transformations(png_ptr, &row_info);

#endif

    * which is also the output depth.

    */

   if (row_info.pixel_depth != png_ptr->pixel_depth ||

      row_info.pixel_depth != png_ptr->transformed_pixel_depth)

      png_error(png_ptr, "internal write transform logic error");

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

   }

#endif

#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED

   /* Check for out-of-range palette index */

   if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&

       png_ptr->num_palette_max >= 0)

      png_do_check_palette_indexes(png_ptr, &row_info);

#endif

   png_write_find_filter(png_ptr, &row_info);

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

}

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

void PNGAPI

png_set_flush(png_structrp png_ptr, int nrows)

{

   png_debug(1, "in png_set_flush");

      return;

}

void PNGAPI

png_write_flush(png_structrp png_ptr)

{

   png_debug(1, "in png_write_flush");

      return;

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

      return;

   png_ptr->flush_rows = 0;

   png_flush(png_ptr);

}

#endif /* PNG_WRITE_FLUSH_SUPPORTED */

static void png_reset_filter_heuristics(png_structrp png_ptr);/* forward decl */

#endif

static void

png_write_destroy(png_structrp png_ptr)

{

   png_debug(1, "in png_write_destroy");

   if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)

      deflateEnd(&png_ptr->zstream);

   png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);

   png_free(png_ptr, png_ptr->row_buf);

#ifdef PNG_WRITE_FILTER_SUPPORTED

   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);

#endif

   /* Use this to save a little code space, it doesn't free the filter_costs */

   png_reset_filter_heuristics(png_ptr);

   png_free(png_ptr, png_ptr->filter_costs);

   png_free(png_ptr, png_ptr->inv_filter_costs);

#endif

   png_free(png_ptr, png_ptr->chunk_list);

#endif

    * point: the jmp_buf may still have to be freed.  See png_destroy_png_struct

    * for how this happens.

    */

}

 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for

 * *png_ptr_ptr.  Prior to 1.6.0 it would accept such a value and it would free

 * the passed in info_structs but it would quietly fail to free any of the data

 * inside them.  In 1.6.0 it quietly does nothing (it has to be quiet because it

 * has no png_ptr.)

 */

void PNGAPI

png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)

{

   png_debug(1, "in png_destroy_write_struct");

   {

      png_structrp png_ptr = *png_ptr_ptr;

      {

         png_destroy_info_struct(png_ptr, info_ptr_ptr);

         png_write_destroy(png_ptr);

         png_destroy_png_struct(png_ptr);

      }

   }

}

void PNGAPI

png_set_filter(png_structrp png_ptr, int method, int filters)

{

   png_debug(1, "in png_set_filter");

      return;

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

       (method == PNG_INTRAPIXEL_DIFFERENCING))

      method = PNG_FILTER_TYPE_BASE;

   if (method == PNG_FILTER_TYPE_BASE)

   {

      switch (filters & (PNG_ALL_FILTERS | 0x07))

      {

#ifdef PNG_WRITE_FILTER_SUPPORTED

         case 5:

         case 6:

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

            /* FALL THROUGH */

#endif /* PNG_WRITE_FILTER_SUPPORTED */

         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;

            png_ptr->do_filter = PNG_FILTER_UP; break;

            png_ptr->do_filter = PNG_FILTER_AVG; break;

            png_ptr->do_filter = PNG_FILTER_PAETH; break;

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

#else

         default:

            png_app_error(png_ptr, "Unknown row filter for method 0");

#endif /* PNG_WRITE_FILTER_SUPPORTED */

      }

       * 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)

      {

#ifdef PNG_WRITE_FILTER_SUPPORTED

         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->prev_row == NULL)

            {

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

               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &

                   ~PNG_FILTER_UP);

            }

            {

               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->prev_row == NULL)

            {

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

               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &

                   ~PNG_FILTER_AVG);

            }

            {

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

                   (png_ptr->rowbytes + 1));

               png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;

            }

         }

             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);

            }

            {

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

                   (png_ptr->rowbytes + 1));

               png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;

            }

         }

#endif /* PNG_WRITE_FILTER_SUPPORTED */

            png_ptr->do_filter = PNG_FILTER_NONE;

      }

   }

   else

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

}

 * 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.

 */

#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED      /* GRR 970116 */

/* Convenience reset API. */

static void

png_reset_filter_heuristics(png_structrp png_ptr)

{

   /* Clear out any old values in the 'weights' - this must be done because if

    * the app calls set_filter_heuristics multiple times with different

    * 'num_weights' values we would otherwise potentially have wrong sized

    * arrays.

    */

   png_ptr->num_prev_filters = 0;

   png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;

   if (png_ptr->prev_filters != NULL)

   {

      png_bytep old = png_ptr->prev_filters;

      png_ptr->prev_filters = NULL;

      png_free(png_ptr, old);

   }

   if (png_ptr->filter_weights != NULL)

   {

      png_uint_16p old = png_ptr->filter_weights;

      png_ptr->filter_weights = NULL;

      png_free(png_ptr, old);

   }

   {

      png_uint_16p old = png_ptr->inv_filter_weights;

      png_ptr->inv_filter_weights = NULL;

      png_free(png_ptr, old);

   }

}

png_init_filter_heuristics(png_structrp png_ptr, int heuristic_method,

   int num_weights)

{

   if (png_ptr == NULL)

      return 0;

   png_reset_filter_heuristics(png_ptr);

    * unweighted case, but we must handle the weight case by initializing the

    * arrays for the caller.

    */

   if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

   {

      int i;

      {

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

             (png_uint_32)((sizeof (png_byte)) * num_weights));