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lightning-sunbird  0.9+nobinonly
Defines | Functions | Variables
pngrtran.c File Reference
#include "png.h"

Go to the source code of this file.

Defines

#define PNG_INTERNAL

Functions

void PNGAPI png_set_crc_action (png_structp png_ptr, int crit_action, int ancil_action)
void PNGAPI png_set_strip_16 (png_structp png_ptr)
void PNGAPI png_set_gamma (png_structp png_ptr, double scrn_gamma, double file_gamma)
void PNGAPI png_set_expand (png_structp png_ptr)
void PNGAPI png_set_palette_to_rgb (png_structp png_ptr)
void PNGAPI png_set_gray_1_2_4_to_8 (png_structp png_ptr)
void PNGAPI png_set_tRNS_to_alpha (png_structp png_ptr)
void PNGAPI png_set_gray_to_rgb (png_structp png_ptr)
void png_init_read_transformations (png_structp png_ptr)
void png_read_transform_info (png_structp png_ptr, png_infop info_ptr)
void png_do_read_transformations (png_structp png_ptr)
void png_do_chop (png_row_infop row_info, png_bytep row)
void png_do_gray_to_rgb (png_row_infop row_info, png_bytep row)
void PNGAPI png_build_grayscale_palette (int bit_depth, png_colorp palette)
void png_do_gamma (png_row_infop row_info, png_bytep row, png_bytep gamma_table, png_uint_16pp gamma_16_table, int gamma_shift)
void png_do_expand_palette (png_row_infop row_info, png_bytep row, png_colorp palette, png_bytep trans, int num_trans)
void png_do_expand (png_row_infop row_info, png_bytep row, png_color_16p trans_value)
void png_build_gamma_table (png_structp png_ptr)

Variables

static int png_gamma_shift []

Define Documentation

Definition at line 16 of file pngrtran.c.


Function Documentation

Definition at line 3906 of file pngrtran.c.

{
  png_debug(1, "in png_build_gamma_table\n");
  if(png_ptr->gamma != 0.0)
  {
   if (png_ptr->bit_depth <= 8)
   {
      int i;
      double g;

      if (png_ptr->screen_gamma > .000001)
         g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
      else
         g = 1.0;

      png_ptr->gamma_table = (png_bytep)png_malloc(png_ptr,
         (png_uint_32)256);

      for (i = 0; i < 256; i++)
      {
         png_ptr->gamma_table[i] = (png_byte)(pow((double)i / 255.0,
            g) * 255.0 + .5);
      }

#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
      if (png_ptr->transformations & ((PNG_BACKGROUND) | PNG_RGB_TO_GRAY))
      {

         g = 1.0 / (png_ptr->gamma);

         png_ptr->gamma_to_1 = (png_bytep)png_malloc(png_ptr,
            (png_uint_32)256);

         for (i = 0; i < 256; i++)
         {
            png_ptr->gamma_to_1[i] = (png_byte)(pow((double)i / 255.0,
               g) * 255.0 + .5);
         }


         png_ptr->gamma_from_1 = (png_bytep)png_malloc(png_ptr,
            (png_uint_32)256);

         if(png_ptr->screen_gamma > 0.000001)
            g = 1.0 / png_ptr->screen_gamma;
         else
            g = png_ptr->gamma;   /* probably doing rgb_to_gray */

         for (i = 0; i < 256; i++)
         {
            png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0,
               g) * 255.0 + .5);

         }
      }
#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
   }
   else
   {
      double g;
      int i, j, shift, num;
      int sig_bit;
      png_uint_32 ig;

      if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
      {
         sig_bit = (int)png_ptr->sig_bit.red;
         if ((int)png_ptr->sig_bit.green > sig_bit)
            sig_bit = png_ptr->sig_bit.green;
         if ((int)png_ptr->sig_bit.blue > sig_bit)
            sig_bit = png_ptr->sig_bit.blue;
      }
      else
      {
         sig_bit = (int)png_ptr->sig_bit.gray;
      }

      if (sig_bit > 0)
         shift = 16 - sig_bit;
      else
         shift = 0;

      if (png_ptr->transformations & PNG_16_TO_8)
      {
         if (shift < (16 - PNG_MAX_GAMMA_8))
            shift = (16 - PNG_MAX_GAMMA_8);
      }

      if (shift > 8)
         shift = 8;
      if (shift < 0)
         shift = 0;

      png_ptr->gamma_shift = (png_byte)shift;

      num = (1 << (8 - shift));

      if (png_ptr->screen_gamma > .000001)
         g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
      else
         g = 1.0;

      png_ptr->gamma_16_table = (png_uint_16pp)png_malloc(png_ptr,
         (png_uint_32)(num * png_sizeof (png_uint_16p)));

      if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND))
      {
         double fin, fout;
         png_uint_32 last, max;

         for (i = 0; i < num; i++)
         {
            png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
               (png_uint_32)(256 * png_sizeof (png_uint_16)));
         }

         g = 1.0 / g;
         last = 0;
         for (i = 0; i < 256; i++)
         {
            fout = ((double)i + 0.5) / 256.0;
            fin = pow(fout, g);
            max = (png_uint_32)(fin * (double)((png_uint_32)num << 8));
            while (last <= max)
            {
               png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
                  [(int)(last >> (8 - shift))] = (png_uint_16)(
                  (png_uint_16)i | ((png_uint_16)i << 8));
               last++;
            }
         }
         while (last < ((png_uint_32)num << 8))
         {
            png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
               [(int)(last >> (8 - shift))] = (png_uint_16)65535L;
            last++;
         }
      }
      else
      {
         for (i = 0; i < num; i++)
         {
            png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
               (png_uint_32)(256 * png_sizeof (png_uint_16)));

            ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4);
            for (j = 0; j < 256; j++)
            {
               png_ptr->gamma_16_table[i][j] =
                  (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
                     65535.0, g) * 65535.0 + .5);
            }
         }
      }

#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
      if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY))
      {

         g = 1.0 / (png_ptr->gamma);

         png_ptr->gamma_16_to_1 = (png_uint_16pp)png_malloc(png_ptr,
            (png_uint_32)(num * png_sizeof (png_uint_16p )));

         for (i = 0; i < num; i++)
         {
            png_ptr->gamma_16_to_1[i] = (png_uint_16p)png_malloc(png_ptr,
               (png_uint_32)(256 * png_sizeof (png_uint_16)));

            ig = (((png_uint_32)i *
               (png_uint_32)png_gamma_shift[shift]) >> 4);
            for (j = 0; j < 256; j++)
            {
               png_ptr->gamma_16_to_1[i][j] =
                  (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
                     65535.0, g) * 65535.0 + .5);
            }
         }

         if(png_ptr->screen_gamma > 0.000001)
            g = 1.0 / png_ptr->screen_gamma;
         else
            g = png_ptr->gamma;   /* probably doing rgb_to_gray */

         png_ptr->gamma_16_from_1 = (png_uint_16pp)png_malloc(png_ptr,
            (png_uint_32)(num * png_sizeof (png_uint_16p)));

         for (i = 0; i < num; i++)
         {
            png_ptr->gamma_16_from_1[i] = (png_uint_16p)png_malloc(png_ptr,
               (png_uint_32)(256 * png_sizeof (png_uint_16)));

            ig = (((png_uint_32)i *
               (png_uint_32)png_gamma_shift[shift]) >> 4);
            for (j = 0; j < 256; j++)
            {
               png_ptr->gamma_16_from_1[i][j] =
                  (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
                     65535.0, g) * 65535.0 + .5);
            }
         }
      }
#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
   }
 }
}

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void PNGAPI png_build_grayscale_palette ( int  bit_depth,
png_colorp  palette 
)

Definition at line 2363 of file pngrtran.c.

{
   int num_palette;
   int color_inc;
   int i;
   int v;

   png_debug(1, "in png_do_build_grayscale_palette\n");
   if (palette == NULL)
      return;

   switch (bit_depth)
   {
      case 1:
         num_palette = 2;
         color_inc = 0xff;
         break;
      case 2:
         num_palette = 4;
         color_inc = 0x55;
         break;
      case 4:
         num_palette = 16;
         color_inc = 0x11;
         break;
      case 8:
         num_palette = 256;
         color_inc = 1;
         break;
      default:
         num_palette = 0;
         color_inc = 0;
         break;
   }

   for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
   {
      palette[i].red = (png_byte)v;
      palette[i].green = (png_byte)v;
      palette[i].blue = (png_byte)v;
   }
}
void png_do_chop ( png_row_infop  row_info,
png_bytep  row 
)

Definition at line 1602 of file pngrtran.c.

{
   png_debug(1, "in png_do_chop\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
   if (row != NULL && row_info != NULL && row_info->bit_depth == 16)
#else
   if (row_info->bit_depth == 16)
#endif
   {
      png_bytep sp = row;
      png_bytep dp = row;
      png_uint_32 i;
      png_uint_32 istop = row_info->width * row_info->channels;

      for (i = 0; i<istop; i++, sp += 2, dp++)
      {
#if defined(PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED)
      /* This does a more accurate scaling of the 16-bit color
       * value, rather than a simple low-byte truncation.
       *
       * What the ideal calculation should be:
       *   *dp = (((((png_uint_32)(*sp) << 8) |
       *          (png_uint_32)(*(sp + 1))) * 255 + 127) / (png_uint_32)65535L;
       *
       * GRR: no, I think this is what it really should be:
       *   *dp = (((((png_uint_32)(*sp) << 8) |
       *           (png_uint_32)(*(sp + 1))) + 128L) / (png_uint_32)257L;
       *
       * GRR: here's the exact calculation with shifts:
       *   temp = (((png_uint_32)(*sp) << 8) | (png_uint_32)(*(sp + 1))) + 128L;
       *   *dp = (temp - (temp >> 8)) >> 8;
       *
       * Approximate calculation with shift/add instead of multiply/divide:
       *   *dp = ((((png_uint_32)(*sp) << 8) |
       *          (png_uint_32)((int)(*(sp + 1)) - *sp)) + 128) >> 8;
       *
       * What we actually do to avoid extra shifting and conversion:
       */

         *dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0);
#else
       /* Simply discard the low order byte */
         *dp = *sp;
#endif
      }
      row_info->bit_depth = 8;
      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
      row_info->rowbytes = row_info->width * row_info->channels;
   }
}

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void png_do_expand ( png_row_infop  row_info,
png_bytep  row,
png_color_16p  trans_value 
)

Definition at line 3608 of file pngrtran.c.

{
   int shift, value;
   png_bytep sp, dp;
   png_uint_32 i;
   png_uint_32 row_width=row_info->width;

   png_debug(1, "in png_do_expand\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
   if (row != NULL && row_info != NULL)
#endif
   {
      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
      {
         png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0);

         if (row_info->bit_depth < 8)
         {
            switch (row_info->bit_depth)
            {
               case 1:
               {
                  gray = (png_uint_16)(gray*0xff);
                  sp = row + (png_size_t)((row_width - 1) >> 3);
                  dp = row + (png_size_t)row_width - 1;
                  shift = 7 - (int)((row_width + 7) & 0x07);
                  for (i = 0; i < row_width; i++)
                  {
                     if ((*sp >> shift) & 0x01)
                        *dp = 0xff;
                     else
                        *dp = 0;
                     if (shift == 7)
                     {
                        shift = 0;
                        sp--;
                     }
                     else
                        shift++;

                     dp--;
                  }
                  break;
               }
               case 2:
               {
                  gray = (png_uint_16)(gray*0x55);
                  sp = row + (png_size_t)((row_width - 1) >> 2);
                  dp = row + (png_size_t)row_width - 1;
                  shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
                  for (i = 0; i < row_width; i++)
                  {
                     value = (*sp >> shift) & 0x03;
                     *dp = (png_byte)(value | (value << 2) | (value << 4) |
                        (value << 6));
                     if (shift == 6)
                     {
                        shift = 0;
                        sp--;
                     }
                     else
                        shift += 2;

                     dp--;
                  }
                  break;
               }
               case 4:
               {
                  gray = (png_uint_16)(gray*0x11);
                  sp = row + (png_size_t)((row_width - 1) >> 1);
                  dp = row + (png_size_t)row_width - 1;
                  shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
                  for (i = 0; i < row_width; i++)
                  {
                     value = (*sp >> shift) & 0x0f;
                     *dp = (png_byte)(value | (value << 4));
                     if (shift == 4)
                     {
                        shift = 0;
                        sp--;
                     }
                     else
                        shift = 4;

                     dp--;
                  }
                  break;
               }
            }
            row_info->bit_depth = 8;
            row_info->pixel_depth = 8;
            row_info->rowbytes = row_width;
         }

         if (trans_value != NULL)
         {
            if (row_info->bit_depth == 8)
            {
               sp = row + (png_size_t)row_width - 1;
               dp = row + (png_size_t)(row_width << 1) - 1;
               for (i = 0; i < row_width; i++)
               {
                  if (*sp == gray)
                     *dp-- = 0;
                  else
                     *dp-- = 0xff;
                  *dp-- = *sp--;
               }
            }
            else if (row_info->bit_depth == 16)
            {
               sp = row + row_info->rowbytes - 1;
               dp = row + (row_info->rowbytes << 1) - 1;
               for (i = 0; i < row_width; i++)
               {
                  if (((png_uint_16)*(sp) |
                     ((png_uint_16)*(sp - 1) << 8)) == gray)
                  {
                     *dp-- = 0;
                     *dp-- = 0;
                  }
                  else
                  {
                     *dp-- = 0xff;
                     *dp-- = 0xff;
                  }
                  *dp-- = *sp--;
                  *dp-- = *sp--;
               }
            }
            row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
            row_info->channels = 2;
            row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
            row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
               row_width);
         }
      }
      else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value)
      {
         if (row_info->bit_depth == 8)
         {
            sp = row + (png_size_t)row_info->rowbytes - 1;
            dp = row + (png_size_t)(row_width << 2) - 1;
            for (i = 0; i < row_width; i++)
            {
               if (*(sp - 2) == trans_value->red &&
                  *(sp - 1) == trans_value->green &&
                  *(sp - 0) == trans_value->blue)
                  *dp-- = 0;
               else
                  *dp-- = 0xff;
               *dp-- = *sp--;
               *dp-- = *sp--;
               *dp-- = *sp--;
            }
         }
         else if (row_info->bit_depth == 16)
         {
            sp = row + row_info->rowbytes - 1;
            dp = row + (png_size_t)(row_width << 3) - 1;
            for (i = 0; i < row_width; i++)
            {
               if ((((png_uint_16)*(sp - 4) |
                  ((png_uint_16)*(sp - 5) << 8)) == trans_value->red) &&
                  (((png_uint_16)*(sp - 2) |
                  ((png_uint_16)*(sp - 3) << 8)) == trans_value->green) &&
                  (((png_uint_16)*(sp - 0) |
                  ((png_uint_16)*(sp - 1) << 8)) == trans_value->blue))
               {
                  *dp-- = 0;
                  *dp-- = 0;
               }
               else
               {
                  *dp-- = 0xff;
                  *dp-- = 0xff;
               }
               *dp-- = *sp--;
               *dp-- = *sp--;
               *dp-- = *sp--;
               *dp-- = *sp--;
               *dp-- = *sp--;
               *dp-- = *sp--;
            }
         }
         row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
         row_info->channels = 4;
         row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
      }
   }
}

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void png_do_expand_palette ( png_row_infop  row_info,
png_bytep  row,
png_colorp  palette,
png_bytep  trans,
int  num_trans 
)

Definition at line 3465 of file pngrtran.c.

{
   int shift, value;
   png_bytep sp, dp;
   png_uint_32 i;
   png_uint_32 row_width=row_info->width;

   png_debug(1, "in png_do_expand_palette\n");
   if (
#if defined(PNG_USELESS_TESTS_SUPPORTED)
       row != NULL && row_info != NULL &&
#endif
       row_info->color_type == PNG_COLOR_TYPE_PALETTE)
   {
      if (row_info->bit_depth < 8)
      {
         switch (row_info->bit_depth)
         {
            case 1:
            {
               sp = row + (png_size_t)((row_width - 1) >> 3);
               dp = row + (png_size_t)row_width - 1;
               shift = 7 - (int)((row_width + 7) & 0x07);
               for (i = 0; i < row_width; i++)
               {
                  if ((*sp >> shift) & 0x01)
                     *dp = 1;
                  else
                     *dp = 0;
                  if (shift == 7)
                  {
                     shift = 0;
                     sp--;
                  }
                  else
                     shift++;

                  dp--;
               }
               break;
            }
            case 2:
            {
               sp = row + (png_size_t)((row_width - 1) >> 2);
               dp = row + (png_size_t)row_width - 1;
               shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
               for (i = 0; i < row_width; i++)
               {
                  value = (*sp >> shift) & 0x03;
                  *dp = (png_byte)value;
                  if (shift == 6)
                  {
                     shift = 0;
                     sp--;
                  }
                  else
                     shift += 2;

                  dp--;
               }
               break;
            }
            case 4:
            {
               sp = row + (png_size_t)((row_width - 1) >> 1);
               dp = row + (png_size_t)row_width - 1;
               shift = (int)((row_width & 0x01) << 2);
               for (i = 0; i < row_width; i++)
               {
                  value = (*sp >> shift) & 0x0f;
                  *dp = (png_byte)value;
                  if (shift == 4)
                  {
                     shift = 0;
                     sp--;
                  }
                  else
                     shift += 4;

                  dp--;
               }
               break;
            }
         }
         row_info->bit_depth = 8;
         row_info->pixel_depth = 8;
         row_info->rowbytes = row_width;
      }
      switch (row_info->bit_depth)
      {
         case 8:
         {
            if (trans != NULL)
            {
               sp = row + (png_size_t)row_width - 1;
               dp = row + (png_size_t)(row_width << 2) - 1;

               for (i = 0; i < row_width; i++)
               {
                  if ((int)(*sp) >= num_trans)
                     *dp-- = 0xff;
                  else
                     *dp-- = trans[*sp];
                  *dp-- = palette[*sp].blue;
                  *dp-- = palette[*sp].green;
                  *dp-- = palette[*sp].red;
                  sp--;
               }
               row_info->bit_depth = 8;
               row_info->pixel_depth = 32;
               row_info->rowbytes = row_width * 4;
               row_info->color_type = 6;
               row_info->channels = 4;
            }
            else
            {
               sp = row + (png_size_t)row_width - 1;
               dp = row + (png_size_t)(row_width * 3) - 1;

               for (i = 0; i < row_width; i++)
               {
                  *dp-- = palette[*sp].blue;
                  *dp-- = palette[*sp].green;
                  *dp-- = palette[*sp].red;
                  sp--;
               }
               row_info->bit_depth = 8;
               row_info->pixel_depth = 24;
               row_info->rowbytes = row_width * 3;
               row_info->color_type = 2;
               row_info->channels = 3;
            }
            break;
         }
      }
   }
}

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void png_do_gamma ( png_row_infop  row_info,
png_bytep  row,
png_bytep  gamma_table,
png_uint_16pp  gamma_16_table,
int  gamma_shift 
)

Definition at line 3283 of file pngrtran.c.

{
   png_bytep sp;
   png_uint_32 i;
   png_uint_32 row_width=row_info->width;

   png_debug(1, "in png_do_gamma\n");
   if (
#if defined(PNG_USELESS_TESTS_SUPPORTED)
       row != NULL && row_info != NULL &&
#endif
       ((row_info->bit_depth <= 8 && gamma_table != NULL) ||
        (row_info->bit_depth == 16 && gamma_16_table != NULL)))
   {
      switch (row_info->color_type)
      {
         case PNG_COLOR_TYPE_RGB:
         {
            if (row_info->bit_depth == 8)
            {
               sp = row;
               for (i = 0; i < row_width; i++)
               {
                  *sp = gamma_table[*sp];
                  sp++;
                  *sp = gamma_table[*sp];
                  sp++;
                  *sp = gamma_table[*sp];
                  sp++;
               }
            }
            else /* if (row_info->bit_depth == 16) */
            {
               sp = row;
               for (i = 0; i < row_width; i++)
               {
                  png_uint_16 v;

                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
                  *sp = (png_byte)((v >> 8) & 0xff);
                  *(sp + 1) = (png_byte)(v & 0xff);
                  sp += 2;
                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
                  *sp = (png_byte)((v >> 8) & 0xff);
                  *(sp + 1) = (png_byte)(v & 0xff);
                  sp += 2;
                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
                  *sp = (png_byte)((v >> 8) & 0xff);
                  *(sp + 1) = (png_byte)(v & 0xff);
                  sp += 2;
               }
            }
            break;
         }
         case PNG_COLOR_TYPE_RGB_ALPHA:
         {
            if (row_info->bit_depth == 8)
            {
               sp = row;
               for (i = 0; i < row_width; i++)
               {
                  *sp = gamma_table[*sp];
                  sp++;
                  *sp = gamma_table[*sp];
                  sp++;
                  *sp = gamma_table[*sp];
                  sp++;
                  sp++;
               }
            }
            else /* if (row_info->bit_depth == 16) */
            {
               sp = row;
               for (i = 0; i < row_width; i++)
               {
                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
                  *sp = (png_byte)((v >> 8) & 0xff);
                  *(sp + 1) = (png_byte)(v & 0xff);
                  sp += 2;
                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
                  *sp = (png_byte)((v >> 8) & 0xff);
                  *(sp + 1) = (png_byte)(v & 0xff);
                  sp += 2;
                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
                  *sp = (png_byte)((v >> 8) & 0xff);
                  *(sp + 1) = (png_byte)(v & 0xff);
                  sp += 4;
               }
            }
            break;
         }
         case PNG_COLOR_TYPE_GRAY_ALPHA:
         {
            if (row_info->bit_depth == 8)
            {
               sp = row;
               for (i = 0; i < row_width; i++)
               {
                  *sp = gamma_table[*sp];
                  sp += 2;
               }
            }
            else /* if (row_info->bit_depth == 16) */
            {
               sp = row;
               for (i = 0; i < row_width; i++)
               {
                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
                  *sp = (png_byte)((v >> 8) & 0xff);
                  *(sp + 1) = (png_byte)(v & 0xff);
                  sp += 4;
               }
            }
            break;
         }
         case PNG_COLOR_TYPE_GRAY:
         {
            if (row_info->bit_depth == 2)
            {
               sp = row;
               for (i = 0; i < row_width; i += 4)
               {
                  int a = *sp & 0xc0;
                  int b = *sp & 0x30;
                  int c = *sp & 0x0c;
                  int d = *sp & 0x03;

                  *sp = (png_byte)(
                        ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)])   ) & 0xc0)|
                        ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
                        ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
                        ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
                  sp++;
               }
            }
            if (row_info->bit_depth == 4)
            {
               sp = row;
               for (i = 0; i < row_width; i += 2)
               {
                  int msb = *sp & 0xf0;
                  int lsb = *sp & 0x0f;

                  *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
                          | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
                  sp++;
               }
            }
            else if (row_info->bit_depth == 8)
            {
               sp = row;
               for (i = 0; i < row_width; i++)
               {
                  *sp = gamma_table[*sp];
                  sp++;
               }
            }
            else if (row_info->bit_depth == 16)
            {
               sp = row;
               for (i = 0; i < row_width; i++)
               {
                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
                  *sp = (png_byte)((v >> 8) & 0xff);
                  *(sp + 1) = (png_byte)(v & 0xff);
                  sp += 2;
               }
            }
            break;
         }
      }
   }
}

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Definition at line 2023 of file pngrtran.c.

{
   png_uint_32 i;
   png_uint_32 row_width = row_info->width;

   png_debug(1, "in png_do_gray_to_rgb\n");
   if (row_info->bit_depth >= 8 &&
#if defined(PNG_USELESS_TESTS_SUPPORTED)
       row != NULL && row_info != NULL &&
#endif
      !(row_info->color_type & PNG_COLOR_MASK_COLOR))
   {
      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
      {
         if (row_info->bit_depth == 8)
         {
            png_bytep sp = row + (png_size_t)row_width - 1;
            png_bytep dp = sp  + (png_size_t)row_width * 2;
            for (i = 0; i < row_width; i++)
            {
               *(dp--) = *sp;
               *(dp--) = *sp;
               *(dp--) = *(sp--);
            }
         }
         else
         {
            png_bytep sp = row + (png_size_t)row_width * 2 - 1;
            png_bytep dp = sp  + (png_size_t)row_width * 4;
            for (i = 0; i < row_width; i++)
            {
               *(dp--) = *sp;
               *(dp--) = *(sp - 1);
               *(dp--) = *sp;
               *(dp--) = *(sp - 1);
               *(dp--) = *(sp--);
               *(dp--) = *(sp--);
            }
         }
      }
      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
      {
         if (row_info->bit_depth == 8)
         {
            png_bytep sp = row + (png_size_t)row_width * 2 - 1;
            png_bytep dp = sp  + (png_size_t)row_width * 2;
            for (i = 0; i < row_width; i++)
            {
               *(dp--) = *(sp--);
               *(dp--) = *sp;
               *(dp--) = *sp;
               *(dp--) = *(sp--);
            }
         }
         else
         {
            png_bytep sp = row + (png_size_t)row_width * 4 - 1;
            png_bytep dp = sp  + (png_size_t)row_width * 4;
            for (i = 0; i < row_width; i++)
            {
               *(dp--) = *(sp--);
               *(dp--) = *(sp--);
               *(dp--) = *sp;
               *(dp--) = *(sp - 1);
               *(dp--) = *sp;
               *(dp--) = *(sp - 1);
               *(dp--) = *(sp--);
               *(dp--) = *(sp--);
            }
         }
      }
      row_info->channels += (png_byte)2;
      row_info->color_type |= PNG_COLOR_MASK_COLOR;
      row_info->pixel_depth = (png_byte)(row_info->channels *
         row_info->bit_depth);
      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
   }
}

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Definition at line 1173 of file pngrtran.c.

{
   png_debug(1, "in png_do_read_transformations\n");
#if !defined(PNG_USELESS_TESTS_SUPPORTED)
   if (png_ptr->row_buf == NULL)
   {
#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
      char msg[50];

      sprintf(msg, "NULL row buffer for row %ld, pass %d", png_ptr->row_number,
         png_ptr->pass);
      png_error(png_ptr, msg);
#else
      png_error(png_ptr, "NULL row buffer");
#endif
   }
#endif

#if defined(PNG_READ_EXPAND_SUPPORTED)
   if (png_ptr->transformations & PNG_EXPAND)
   {
      if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE)
      {
         png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1,
            png_ptr->palette, png_ptr->trans, png_ptr->num_trans);
      }
      else
      {
         if (png_ptr->num_trans)
            png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
               &(png_ptr->trans_values));
         else
            png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
               NULL);
      }
   }
#endif

#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
   if (png_ptr->transformations & PNG_STRIP_ALPHA)
      png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
         PNG_FLAG_FILLER_AFTER);
#endif

#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
   {
      int rgb_error =
         png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info), png_ptr->row_buf + 1);
      if(rgb_error)
      {
         png_ptr->rgb_to_gray_status=1;
         if(png_ptr->transformations == PNG_RGB_TO_GRAY_WARN)
            png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
         if(png_ptr->transformations == PNG_RGB_TO_GRAY_ERR)
            png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
      }
   }
#endif

/*
From Andreas Dilger e-mail to png-implement, 26 March 1998:

  In most cases, the "simple transparency" should be done prior to doing
  gray-to-RGB, or you will have to test 3x as many bytes to check if a
  pixel is transparent.  You would also need to make sure that the
  transparency information is upgraded to RGB.

  To summarize, the current flow is:
  - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
                                  with background "in place" if transparent,
                                  convert to RGB if necessary
  - Gray + alpha -> composite with gray background and remove alpha bytes,
                                  convert to RGB if necessary

  To support RGB backgrounds for gray images we need:
  - Gray + simple transparency -> convert to RGB + simple transparency, compare
                                  3 or 6 bytes and composite with background
                                  "in place" if transparent (3x compare/pixel
                                  compared to doing composite with gray bkgrnd)
  - Gray + alpha -> convert to RGB + alpha, composite with background and
                                  remove alpha bytes (3x float operations/pixel
                                  compared with composite on gray background)

  Greg's change will do this.  The reason it wasn't done before is for
  performance, as this increases the per-pixel operations.  If we would check
  in advance if the background was gray or RGB, and position the gray-to-RGB
  transform appropriately, then it would save a lot of work/time.
 */

#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
   /* if gray -> RGB, do so now only if background is non-gray; else do later
    * for performance reasons */
   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
       !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
      png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif

#if defined(PNG_READ_BACKGROUND_SUPPORTED)
   if ((png_ptr->transformations & PNG_BACKGROUND) &&
      ((png_ptr->num_trans != 0 ) ||
      (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)))
      png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1,
         &(png_ptr->trans_values), &(png_ptr->background)
#if defined(PNG_READ_GAMMA_SUPPORTED)
         , &(png_ptr->background_1),
         png_ptr->gamma_table, png_ptr->gamma_from_1,
         png_ptr->gamma_to_1, png_ptr->gamma_16_table,
         png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1,
         png_ptr->gamma_shift
#endif
);
#endif

#if defined(PNG_READ_GAMMA_SUPPORTED)
   if ((png_ptr->transformations & PNG_GAMMA) &&
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
      !((png_ptr->transformations & PNG_BACKGROUND) &&
      ((png_ptr->num_trans != 0) ||
      (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
#endif
      (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
      png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1,
         png_ptr->gamma_table, png_ptr->gamma_16_table,
         png_ptr->gamma_shift);
#endif

#if defined(PNG_READ_16_TO_8_SUPPORTED)
   if (png_ptr->transformations & PNG_16_TO_8)
      png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif

#if defined(PNG_READ_DITHER_SUPPORTED)
   if (png_ptr->transformations & PNG_DITHER)
   {
      png_do_dither((png_row_infop)&(png_ptr->row_info), png_ptr->row_buf + 1,
         png_ptr->palette_lookup, png_ptr->dither_index);
      if(png_ptr->row_info.rowbytes == (png_uint_32)0)
         png_error(png_ptr, "png_do_dither returned rowbytes=0");
   }
#endif

#if defined(PNG_READ_INVERT_SUPPORTED)
   if (png_ptr->transformations & PNG_INVERT_MONO)
      png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif

#if defined(PNG_READ_SHIFT_SUPPORTED)
   if (png_ptr->transformations & PNG_SHIFT)
      png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1,
         &(png_ptr->shift));
#endif

#if defined(PNG_READ_PACK_SUPPORTED)
   if (png_ptr->transformations & PNG_PACK)
      png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif

#if defined(PNG_READ_BGR_SUPPORTED)
   if (png_ptr->transformations & PNG_BGR)
      png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif

#if defined(PNG_READ_PACKSWAP_SUPPORTED)
   if (png_ptr->transformations & PNG_PACKSWAP)
      png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif

#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
   /* if gray -> RGB, do so now only if we did not do so above */
   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
      png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif

#if defined(PNG_READ_FILLER_SUPPORTED)
   if (png_ptr->transformations & PNG_FILLER)
      png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
         (png_uint_32)png_ptr->filler, png_ptr->flags);
#endif

#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
   if (png_ptr->transformations & PNG_INVERT_ALPHA)
      png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif

#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
   if (png_ptr->transformations & PNG_SWAP_ALPHA)
      png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif

#if defined(PNG_READ_SWAP_SUPPORTED)
   if (png_ptr->transformations & PNG_SWAP_BYTES)
      png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif

#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
   if (png_ptr->transformations & PNG_USER_TRANSFORM)
    {
      if(png_ptr->read_user_transform_fn != NULL)
        (*(png_ptr->read_user_transform_fn)) /* user read transform function */
          (png_ptr,                    /* png_ptr */
           &(png_ptr->row_info),       /* row_info:     */
             /*  png_uint_32 width;          width of row */
             /*  png_uint_32 rowbytes;       number of bytes in row */
             /*  png_byte color_type;        color type of pixels */
             /*  png_byte bit_depth;         bit depth of samples */
             /*  png_byte channels;          number of channels (1-4) */
             /*  png_byte pixel_depth;       bits per pixel (depth*channels) */
           png_ptr->row_buf + 1);      /* start of pixel data for row */
#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
      if(png_ptr->user_transform_depth)
         png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;
      if(png_ptr->user_transform_channels)
         png_ptr->row_info.channels = png_ptr->user_transform_channels;
#endif
      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);
   }
#endif

}

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Definition at line 690 of file pngrtran.c.

{
   png_debug(1, "in png_init_read_transformations\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
   if(png_ptr != NULL)
#endif
  {
#if defined(PNG_READ_BACKGROUND_SUPPORTED) || defined(PNG_READ_SHIFT_SUPPORTED) \
 || defined(PNG_READ_GAMMA_SUPPORTED)
   int color_type = png_ptr->color_type;
#endif

#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
       (png_ptr->transformations & PNG_EXPAND))
   {
      if (!(color_type & PNG_COLOR_MASK_COLOR))  /* i.e., GRAY or GRAY_ALPHA */
      {
         /* expand background chunk. */
         switch (png_ptr->bit_depth)
         {
            case 1:
               png_ptr->background.gray *= (png_uint_16)0xff;
               png_ptr->background.red = png_ptr->background.green
                 =  png_ptr->background.blue = png_ptr->background.gray;
               break;
            case 2:
               png_ptr->background.gray *= (png_uint_16)0x55;
               png_ptr->background.red = png_ptr->background.green
                 = png_ptr->background.blue = png_ptr->background.gray;
               break;
            case 4:
               png_ptr->background.gray *= (png_uint_16)0x11;
               png_ptr->background.red = png_ptr->background.green
                 = png_ptr->background.blue = png_ptr->background.gray;
               break;
            case 8:
            case 16:
               png_ptr->background.red = png_ptr->background.green
                 = png_ptr->background.blue = png_ptr->background.gray;
               break;
         }
      }
      else if (color_type == PNG_COLOR_TYPE_PALETTE)
      {
         png_ptr->background.red   =
            png_ptr->palette[png_ptr->background.index].red;
         png_ptr->background.green =
            png_ptr->palette[png_ptr->background.index].green;
         png_ptr->background.blue  =
            png_ptr->palette[png_ptr->background.index].blue;

#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
        if (png_ptr->transformations & PNG_INVERT_ALPHA)
        {
#if defined(PNG_READ_EXPAND_SUPPORTED)
           if (!(png_ptr->transformations & PNG_EXPAND))
#endif
           {
           /* invert the alpha channel (in tRNS) unless the pixels are
              going to be expanded, in which case leave it for later */
              int i,istop;
              istop=(int)png_ptr->num_trans;
              for (i=0; i<istop; i++)
                 png_ptr->trans[i] = (png_byte)(255 - png_ptr->trans[i]);
           }
        }
#endif

      }
   }
#endif

#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
   png_ptr->background_1 = png_ptr->background;
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)

   if ((color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_trans != 0)
       && (fabs(png_ptr->screen_gamma * png_ptr->gamma - 1.0)
         < PNG_GAMMA_THRESHOLD))
   {
    int i,k;
    k=0;
    for (i=0; i<png_ptr->num_trans; i++)
    {
      if (png_ptr->trans[i] != 0 && png_ptr->trans[i] != 0xff)
        k=1; /* partial transparency is present */
    }
    if (k == 0)
      png_ptr->transformations &= (~PNG_GAMMA);
   }

   if (png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY))
   {
      png_build_gamma_table(png_ptr);
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
      if (png_ptr->transformations & PNG_BACKGROUND)
      {
         if (color_type == PNG_COLOR_TYPE_PALETTE)
         {
           /* could skip if no transparency and 
           */
            png_color back, back_1;
            png_colorp palette = png_ptr->palette;
            int num_palette = png_ptr->num_palette;
            int i;
            if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
            {
               back.red = png_ptr->gamma_table[png_ptr->background.red];
               back.green = png_ptr->gamma_table[png_ptr->background.green];
               back.blue = png_ptr->gamma_table[png_ptr->background.blue];

               back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
               back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
               back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
            }
            else
            {
               double g, gs;

               switch (png_ptr->background_gamma_type)
               {
                  case PNG_BACKGROUND_GAMMA_SCREEN:
                     g = (png_ptr->screen_gamma);
                     gs = 1.0;
                     break;
                  case PNG_BACKGROUND_GAMMA_FILE:
                     g = 1.0 / (png_ptr->gamma);
                     gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
                     break;
                  case PNG_BACKGROUND_GAMMA_UNIQUE:
                     g = 1.0 / (png_ptr->background_gamma);
                     gs = 1.0 / (png_ptr->background_gamma *
                                 png_ptr->screen_gamma);
                     break;
                  default:
                     g = 1.0;    /* back_1 */
                     gs = 1.0;   /* back */
               }

               if ( fabs(gs - 1.0) < PNG_GAMMA_THRESHOLD)
               {
                  back.red   = (png_byte)png_ptr->background.red;
                  back.green = (png_byte)png_ptr->background.green;
                  back.blue  = (png_byte)png_ptr->background.blue;
               }
               else
               {
                  back.red = (png_byte)(pow(
                     (double)png_ptr->background.red/255, gs) * 255.0 + .5);
                  back.green = (png_byte)(pow(
                     (double)png_ptr->background.green/255, gs) * 255.0 + .5);
                  back.blue = (png_byte)(pow(
                     (double)png_ptr->background.blue/255, gs) * 255.0 + .5);
               }

               back_1.red = (png_byte)(pow(
                  (double)png_ptr->background.red/255, g) * 255.0 + .5);
               back_1.green = (png_byte)(pow(
                  (double)png_ptr->background.green/255, g) * 255.0 + .5);
               back_1.blue = (png_byte)(pow(
                  (double)png_ptr->background.blue/255, g) * 255.0 + .5);
            }
            for (i = 0; i < num_palette; i++)
            {
               if (i < (int)png_ptr->num_trans && png_ptr->trans[i] != 0xff)
               {
                  if (png_ptr->trans[i] == 0)
                  {
                     palette[i] = back;
                  }
                  else /* if (png_ptr->trans[i] != 0xff) */
                  {
                     png_byte v, w;

                     v = png_ptr->gamma_to_1[palette[i].red];
                     png_composite(w, v, png_ptr->trans[i], back_1.red);
                     palette[i].red = png_ptr->gamma_from_1[w];

                     v = png_ptr->gamma_to_1[palette[i].green];
                     png_composite(w, v, png_ptr->trans[i], back_1.green);
                     palette[i].green = png_ptr->gamma_from_1[w];

                     v = png_ptr->gamma_to_1[palette[i].blue];
                     png_composite(w, v, png_ptr->trans[i], back_1.blue);
                     palette[i].blue = png_ptr->gamma_from_1[w];
                  }
               }
               else
               {
                  palette[i].red = png_ptr->gamma_table[palette[i].red];
                  palette[i].green = png_ptr->gamma_table[palette[i].green];
                  palette[i].blue = png_ptr->gamma_table[palette[i].blue];
               }
            }
         }
         /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
         else
         /* color_type != PNG_COLOR_TYPE_PALETTE */
         {
            double m = (double)(((png_uint_32)1 << png_ptr->bit_depth) - 1);
            double g = 1.0;
            double gs = 1.0;

            switch (png_ptr->background_gamma_type)
            {
               case PNG_BACKGROUND_GAMMA_SCREEN:
                  g = (png_ptr->screen_gamma);
                  gs = 1.0;
                  break;
               case PNG_BACKGROUND_GAMMA_FILE:
                  g = 1.0 / (png_ptr->gamma);
                  gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
                  break;
               case PNG_BACKGROUND_GAMMA_UNIQUE:
                  g = 1.0 / (png_ptr->background_gamma);
                  gs = 1.0 / (png_ptr->background_gamma *
                     png_ptr->screen_gamma);
                  break;
            }

            png_ptr->background_1.gray = (png_uint_16)(pow(
               (double)png_ptr->background.gray / m, g) * m + .5);
            png_ptr->background.gray = (png_uint_16)(pow(
               (double)png_ptr->background.gray / m, gs) * m + .5);

            if ((png_ptr->background.red != png_ptr->background.green) ||
                (png_ptr->background.red != png_ptr->background.blue) ||
                (png_ptr->background.red != png_ptr->background.gray))
            {
               /* RGB or RGBA with color background */
               png_ptr->background_1.red = (png_uint_16)(pow(
                  (double)png_ptr->background.red / m, g) * m + .5);
               png_ptr->background_1.green = (png_uint_16)(pow(
                  (double)png_ptr->background.green / m, g) * m + .5);
               png_ptr->background_1.blue = (png_uint_16)(pow(
                  (double)png_ptr->background.blue / m, g) * m + .5);
               png_ptr->background.red = (png_uint_16)(pow(
                  (double)png_ptr->background.red / m, gs) * m + .5);
               png_ptr->background.green = (png_uint_16)(pow(
                  (double)png_ptr->background.green / m, gs) * m + .5);
               png_ptr->background.blue = (png_uint_16)(pow(
                  (double)png_ptr->background.blue / m, gs) * m + .5);
            }
            else
            {
               /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
               png_ptr->background_1.red = png_ptr->background_1.green
                 = png_ptr->background_1.blue = png_ptr->background_1.gray;
               png_ptr->background.red = png_ptr->background.green
                 = png_ptr->background.blue = png_ptr->background.gray;
            }
         }
      }
      else
      /* transformation does not include PNG_BACKGROUND */
#endif /* PNG_READ_BACKGROUND_SUPPORTED */
      if (color_type == PNG_COLOR_TYPE_PALETTE)
      {
         png_colorp palette = png_ptr->palette;
         int num_palette = png_ptr->num_palette;
         int i;

         for (i = 0; i < num_palette; i++)
         {
            palette[i].red = png_ptr->gamma_table[palette[i].red];
            palette[i].green = png_ptr->gamma_table[palette[i].green];
            palette[i].blue = png_ptr->gamma_table[palette[i].blue];
         }
      }
   }
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
   else
#endif
#endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
   /* No GAMMA transformation */
   if ((png_ptr->transformations & PNG_BACKGROUND) &&
       (color_type == PNG_COLOR_TYPE_PALETTE))
   {
      int i;
      int istop = (int)png_ptr->num_trans;
      png_color back;
      png_colorp palette = png_ptr->palette;

      back.red   = (png_byte)png_ptr->background.red;
      back.green = (png_byte)png_ptr->background.green;
      back.blue  = (png_byte)png_ptr->background.blue;

      for (i = 0; i < istop; i++)
      {
         if (png_ptr->trans[i] == 0)
         {
            palette[i] = back;
         }
         else if (png_ptr->trans[i] != 0xff)
         {
            /* The png_composite() macro is defined in png.h */
            png_composite(palette[i].red, palette[i].red,
               png_ptr->trans[i], back.red);
            png_composite(palette[i].green, palette[i].green,
               png_ptr->trans[i], back.green);
            png_composite(palette[i].blue, palette[i].blue,
               png_ptr->trans[i], back.blue);
         }
      }
   }
#endif /* PNG_READ_BACKGROUND_SUPPORTED */

#if defined(PNG_READ_SHIFT_SUPPORTED)
   if ((png_ptr->transformations & PNG_SHIFT) &&
      (color_type == PNG_COLOR_TYPE_PALETTE))
   {
      png_uint_16 i;
      png_uint_16 istop = png_ptr->num_palette;
      int sr = 8 - png_ptr->sig_bit.red;
      int sg = 8 - png_ptr->sig_bit.green;
      int sb = 8 - png_ptr->sig_bit.blue;

      if (sr < 0 || sr > 8)
         sr = 0;
      if (sg < 0 || sg > 8)
         sg = 0;
      if (sb < 0 || sb > 8)
         sb = 0;
      for (i = 0; i < istop; i++)
      {
         png_ptr->palette[i].red >>= sr;
         png_ptr->palette[i].green >>= sg;
         png_ptr->palette[i].blue >>= sb;
      }
   }
#endif  /* PNG_READ_SHIFT_SUPPORTED */
 }
#if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
 && !defined(PNG_READ_BACKGROUND_SUPPORTED)
   if(png_ptr)
      return;
#endif
}

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void png_read_transform_info ( png_structp  png_ptr,
png_infop  info_ptr 
)

Definition at line 1037 of file pngrtran.c.

{
   png_debug(1, "in png_read_transform_info\n");
#if defined(PNG_READ_EXPAND_SUPPORTED)
   if (png_ptr->transformations & PNG_EXPAND)
   {
      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
         if (png_ptr->num_trans)
            info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
         else
            info_ptr->color_type = PNG_COLOR_TYPE_RGB;
         info_ptr->bit_depth = 8;
         info_ptr->num_trans = 0;
      }
      else
      {
         if (png_ptr->num_trans)
            info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
         if (info_ptr->bit_depth < 8)
            info_ptr->bit_depth = 8;
         info_ptr->num_trans = 0;
      }
   }
#endif

#if defined(PNG_READ_BACKGROUND_SUPPORTED)
   if (png_ptr->transformations & PNG_BACKGROUND)
   {
      info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
      info_ptr->num_trans = 0;
      info_ptr->background = png_ptr->background;
   }
#endif

#if defined(PNG_READ_GAMMA_SUPPORTED)
   if (png_ptr->transformations & PNG_GAMMA)
   {
#ifdef PNG_FLOATING_POINT_SUPPORTED
      info_ptr->gamma = png_ptr->gamma;
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
      info_ptr->int_gamma = png_ptr->int_gamma;
#endif
   }
#endif

#if defined(PNG_READ_16_TO_8_SUPPORTED)
   if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16))
      info_ptr->bit_depth = 8;
#endif

#if defined(PNG_READ_DITHER_SUPPORTED)
   if (png_ptr->transformations & PNG_DITHER)
   {
      if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
         (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
         png_ptr->palette_lookup && info_ptr->bit_depth == 8)
      {
         info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
      }
   }
#endif

#if defined(PNG_READ_PACK_SUPPORTED)
   if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
      info_ptr->bit_depth = 8;
#endif

#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
   if (png_ptr->transformations & PNG_GRAY_TO_RGB)
      info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
#endif

#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
      info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR;
#endif

   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      info_ptr->channels = 1;
   else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
      info_ptr->channels = 3;
   else
      info_ptr->channels = 1;

#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
   if (png_ptr->transformations & PNG_STRIP_ALPHA)
      info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
#endif

   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
      info_ptr->channels++;

#if defined(PNG_READ_FILLER_SUPPORTED)
   /* STRIP_ALPHA and FILLER allowed:  MASK_ALPHA bit stripped above */
   if ((png_ptr->transformations & PNG_FILLER) &&
       ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
       (info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
   {
      info_ptr->channels++;
      /* if adding a true alpha channel not just filler */
#if !defined(PNG_1_0_X)
      if (png_ptr->transformations & PNG_ADD_ALPHA)
        info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
#endif
   }
#endif

#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
   if(png_ptr->transformations & PNG_USER_TRANSFORM)
     {
       if(info_ptr->bit_depth < png_ptr->user_transform_depth)
         info_ptr->bit_depth = png_ptr->user_transform_depth;
       if(info_ptr->channels < png_ptr->user_transform_channels)
         info_ptr->channels = png_ptr->user_transform_channels;
     }
#endif

   info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
      info_ptr->bit_depth);

   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth,info_ptr->width);

#if !defined(PNG_READ_EXPAND_SUPPORTED)
   if(png_ptr)
      return;
#endif
}

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void PNGAPI png_set_crc_action ( png_structp  png_ptr,
int  crit_action,
int  ancil_action 
)

Definition at line 21 of file pngrtran.c.

{
   png_debug(1, "in png_set_crc_action\n");
   /* Tell libpng how we react to CRC errors in critical chunks */
   switch (crit_action)
   {
      case PNG_CRC_NO_CHANGE:                        /* leave setting as is */
         break;
      case PNG_CRC_WARN_USE:                               /* warn/use data */
         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
         png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
         break;
      case PNG_CRC_QUIET_USE:                             /* quiet/use data */
         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
         png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
                           PNG_FLAG_CRC_CRITICAL_IGNORE;
         break;
      case PNG_CRC_WARN_DISCARD:    /* not a valid action for critical data */
         png_warning(png_ptr, "Can't discard critical data on CRC error.");
      case PNG_CRC_ERROR_QUIT:                                /* error/quit */
      case PNG_CRC_DEFAULT:
      default:
         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
         break;
   }

   switch (ancil_action)
   {
      case PNG_CRC_NO_CHANGE:                       /* leave setting as is */
         break;
      case PNG_CRC_WARN_USE:                              /* warn/use data */
         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
         break;
      case PNG_CRC_QUIET_USE:                            /* quiet/use data */
         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
                           PNG_FLAG_CRC_ANCILLARY_NOWARN;
         break;
      case PNG_CRC_ERROR_QUIT:                               /* error/quit */
         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
         break;
      case PNG_CRC_WARN_DISCARD:                      /* warn/discard data */
      case PNG_CRC_DEFAULT:
      default:
         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
         break;
   }
}

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Definition at line 549 of file pngrtran.c.

{
   png_debug(1, "in png_set_expand\n");
   png_ptr->transformations |= PNG_EXPAND;
}

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void PNGAPI png_set_gamma ( png_structp  png_ptr,
double  scrn_gamma,
double  file_gamma 
)

Definition at line 531 of file pngrtran.c.

{
   png_debug(1, "in png_set_gamma\n");
   if ((fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD) ||
       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) ||
       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
     png_ptr->transformations |= PNG_GAMMA;
   png_ptr->gamma = (float)file_gamma;
   png_ptr->screen_gamma = (float)scrn_gamma;
}

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Definition at line 579 of file pngrtran.c.

{
   png_debug(1, "in png_set_expand\n");
   png_ptr->transformations |= PNG_EXPAND;
}

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Definition at line 596 of file pngrtran.c.

{
   png_debug(1, "in png_set_gray_to_rgb\n");
   png_ptr->transformations |= PNG_GRAY_TO_RGB;
}

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Definition at line 571 of file pngrtran.c.

{
   png_debug(1, "in png_set_expand\n");
   png_ptr->transformations |= PNG_EXPAND;
}

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Definition at line 110 of file pngrtran.c.

{
   png_debug(1, "in png_set_strip_16\n");
   png_ptr->transformations |= PNG_16_TO_8;
}

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Definition at line 587 of file pngrtran.c.

{
   png_debug(1, "in png_set_expand\n");
   png_ptr->transformations |= PNG_EXPAND;
}

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Variable Documentation

int png_gamma_shift[] [static]
Initial value:
   {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0, 0x00}

Definition at line 3897 of file pngrtran.c.