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src/Source/LibPNG/pngwutil.c  view on Meta::CPAN

   png_debug(1, "in png_write_tRNS");

   if (color_type == PNG_COLOR_TYPE_PALETTE)
   {
      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
      {
         png_app_warning(png_ptr,
             "Invalid number of transparent colors specified");
         return;
      }

      /* Write the chunk out as it is */
      png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
         (png_size_t)num_trans);
   }

   else if (color_type == PNG_COLOR_TYPE_GRAY)
   {
      /* One 16 bit value */
      if (tran->gray >= (1 << png_ptr->bit_depth))
      {
         png_app_warning(png_ptr,
             "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");

         return;
      }

      png_save_uint_16(buf, tran->gray);
      png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
   }

   else if (color_type == PNG_COLOR_TYPE_RGB)
   {
      /* Three 16 bit values */
      png_save_uint_16(buf, tran->red);
      png_save_uint_16(buf + 2, tran->green);
      png_save_uint_16(buf + 4, tran->blue);
#ifdef PNG_WRITE_16BIT_SUPPORTED
      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
#else
      if ((buf[0] | buf[2] | buf[4]) != 0)
#endif
      {
         png_app_warning(png_ptr,
           "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
         return;
      }

      png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
   }

   else
   {
      png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");
   }
}
#endif

#ifdef PNG_WRITE_bKGD_SUPPORTED
/* Write the background chunk */
void /* PRIVATE */
png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
{
   png_byte buf[6];

   png_debug(1, "in png_write_bKGD");

   if (color_type == PNG_COLOR_TYPE_PALETTE)
   {
      if (
#ifdef PNG_MNG_FEATURES_SUPPORTED
          (png_ptr->num_palette != 0 ||
          (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
#endif
         back->index >= png_ptr->num_palette)
      {
         png_warning(png_ptr, "Invalid background palette index");
         return;
      }

      buf[0] = back->index;
      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
   }

   else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      png_save_uint_16(buf, back->red);
      png_save_uint_16(buf + 2, back->green);
      png_save_uint_16(buf + 4, back->blue);
#ifdef PNG_WRITE_16BIT_SUPPORTED
      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
#else
      if ((buf[0] | buf[2] | buf[4]) != 0)
#endif
      {
         png_warning(png_ptr,
             "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");

         return;
      }

      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
   }

   else
   {
      if (back->gray >= (1 << png_ptr->bit_depth))
      {
         png_warning(png_ptr,
             "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");

         return;
      }

      png_save_uint_16(buf, back->gray);
      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
   }
}
#endif

#ifdef PNG_WRITE_hIST_SUPPORTED
/* Write the histogram */
void /* PRIVATE */
png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist)
{
   int i;
   png_byte buf[3];

   png_debug(1, "in png_write_hIST");

   if (num_hist > (int)png_ptr->num_palette)
   {
      png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
          png_ptr->num_palette);

      png_warning(png_ptr, "Invalid number of histogram entries specified");
      return;