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pngrtran.c：源码内容

*(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);
}
}
#endif
#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
/* reduce RGB files to grayscale, with or without alpha
* using the equation given in Poynton's ColorFAQ at
* <http://www.inforamp.net/~poynton/>
*
* Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
*
* We approximate this with
*
* Y = 0.21268 * R + 0.7151 * G + 0.07217 * B
*
* which can be expressed with integers as
*
* Y = (6969 * R + 23434 * G + 2365 * B)/32768
*
* The calculation is to be done in a linear colorspace.
*
* Other integer coefficents can be used via png_set_rgb_to_gray().
*/
int /* PRIVATE */
png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
{
png_uint_32 i;
png_uint_32 row_width = row_info->width;
int rgb_error = 0;
png_debug(1, "in png_do_rgb_to_grayn");
if (
#if defined(PNG_USELESS_TESTS_SUPPORTED)
row != NULL && row_info != NULL &&
#endif
(row_info->color_type & PNG_COLOR_MASK_COLOR))
{
png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
png_uint_32 bc = png_ptr->rgb_to_gray_blue_coeff;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
{
if (row_info->bit_depth == 8)
{
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
{
png_bytep sp = row;
png_bytep dp = row;
for (i = 0; i < row_width; i++)
{
png_byte red = png_ptr->gamma_to_1[*(sp++)];
png_byte green = png_ptr->gamma_to_1[*(sp++)];
png_byte blue = png_ptr->gamma_to_1[*(sp++)];
if(red != green || red != blue)
{
rgb_error |= 1;
*(dp++) = png_ptr->gamma_from_1[
(rc*red+gc*green+bc*blue)>>15];
}
else
*(dp++) = *(sp-1);
}
}
else
#endif
{
png_bytep sp = row;
png_bytep dp = row;
for (i = 0; i < row_width; i++)
{
png_byte red = *(sp++);
png_byte green = *(sp++);
png_byte blue = *(sp++);
if(red != green || red != blue)
{
rgb_error |= 1;
*(dp++) = (png_byte)((rc*red+gc*green+bc*blue)>>15);
}
else
*(dp++) = *(sp-1);
}
}
}
else /* RGB bit_depth == 16 */
{
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
if (png_ptr->gamma_16_to_1 != NULL &&
png_ptr->gamma_16_from_1 != NULL)
{
png_bytep sp = row;
png_bytep dp = row;
for (i = 0; i < row_width; i++)
{
png_uint_16 red, green, blue, w;
red = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
blue = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
if(red == green && red == blue)
w = red;
else
{
png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >>
png_ptr->gamma_shift][red>>8];
png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >>
png_ptr->gamma_shift][green>>8];
png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >>
png_ptr->gamma_shift][blue>>8];
png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
+ bc*blue_1)>>15);
w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
png_ptr->gamma_shift][gray16 >> 8];
rgb_error |= 1;
}
*(dp++) = (png_byte)((w>>8) & 0xff);
*(dp++) = (png_byte)(w & 0xff);
}
}
else
#endif
{
png_bytep sp = row;
png_bytep dp = row;
for (i = 0; i < row_width; i++)
{
png_uint_16 red, green, blue, gray16;
red = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
blue = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
if(red != green || red != blue)
rgb_error |= 1;
gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
*(dp++) = (png_byte)((gray16>>8) & 0xff);
*(dp++) = (png_byte)(gray16 & 0xff);
}
}
}
}
if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
{
if (row_info->bit_depth == 8)
{
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
{
png_bytep sp = row;
png_bytep dp = row;
for (i = 0; i < row_width; i++)
{
png_byte red = png_ptr->gamma_to_1[*(sp++)];
png_byte green = png_ptr->gamma_to_1[*(sp++)];
png_byte blue = png_ptr->gamma_to_1[*(sp++)];
if(red != green || red != blue)
rgb_error |= 1;
*(dp++) = png_ptr->gamma_from_1
[(rc*red + gc*green + bc*blue)>>15];
*(dp++) = *(sp++); /* alpha */
}
}
else
#endif
{
png_bytep sp = row;
png_bytep dp = row;
for (i = 0; i < row_width; i++)
{
png_byte red = *(sp++);
png_byte green = *(sp++);
png_byte blue = *(sp++);
if(red != green || red != blue)
rgb_error |= 1;
*(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
*(dp++) = *(sp++); /* alpha */
}
}
}
else /* RGBA bit_depth == 16 */
{
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
if (png_ptr->gamma_16_to_1 != NULL &&
png_ptr->gamma_16_from_1 != NULL)
{
png_bytep sp = row;
png_bytep dp = row;
for (i = 0; i < row_width; i++)
{
png_uint_16 red, green, blue, w;
red = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
blue = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
if(red == green && red == blue)
w = red;
else
{
png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >>
png_ptr->gamma_shift][red>>8];
png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >>
png_ptr->gamma_shift][green>>8];
png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >>
png_ptr->gamma_shift][blue>>8];
png_uint_16 gray16 = (png_uint_16)((rc * red_1
+ gc * green_1 + bc * blue_1)>>15);
w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
png_ptr->gamma_shift][gray16 >> 8];
rgb_error |= 1;
}
*(dp++) = (png_byte)((w>>8) & 0xff);
*(dp++) = (png_byte)(w & 0xff);
*(dp++) = *(sp++); /* alpha */
*(dp++) = *(sp++);
}
}
else
#endif
{
png_bytep sp = row;
png_bytep dp = row;
for (i = 0; i < row_width; i++)
{
png_uint_16 red, green, blue, gray16;
red = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
green = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
blue = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
if(red != green || red != blue)
rgb_error |= 1;
gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
*(dp++) = (png_byte)((gray16>>8) & 0xff);
*(dp++) = (png_byte)(gray16 & 0xff);
*(dp++) = *(sp++); /* alpha */
*(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);
}
return rgb_error;
}
#endif
/* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
* large of png_color. This lets grayscale images be treated as
* paletted. Most useful for gamma correction and simplification
* of code.
*/
void PNGAPI
png_build_grayscale_palette(int bit_depth, png_colorp palette)
{
int num_palette;
int color_inc;
int i;
int v;
png_debug(1, "in png_do_build_grayscale_paletten");
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;
}
}
/* This function is currently unused. Do we really need it? */
#if defined(PNG_READ_DITHER_SUPPORTED) && defined(PNG_CORRECT_PALETTE_SUPPORTED)
void /* PRIVATE */
png_correct_palette(png_structp png_ptr, png_colorp palette,
int num_palette)
{
png_debug(1, "in png_correct_paletten");
#if defined(PNG_READ_BACKGROUND_SUPPORTED) &&
defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
if (png_ptr->transformations & (PNG_GAMMA | PNG_BACKGROUND))
{
png_color back, back_1;
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;
g = 1.0 / (png_ptr->background_gamma * png_ptr->screen_gamma);
if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_SCREEN ||
fabs(g - 1.0) < PNG_GAMMA_THRESHOLD)
{
back.red = png_ptr->background.red;
back.green = png_ptr->background.green;
back.blue = png_ptr->background.blue;
}
else
{
back.red =
(png_byte)(pow((double)png_ptr->background.red/255, g) *
255.0 + 0.5);
back.green =
(png_byte)(pow((double)png_ptr->background.green/255, g) *
255.0 + 0.5);
back.blue =
(png_byte)(pow((double)png_ptr->background.blue/255, g) *
255.0 + 0.5);
}
g = 1.0 / png_ptr->background_gamma;
back_1.red =
(png_byte)(pow((double)png_ptr->background.red/255, g) *
255.0 + 0.5);
back_1.green =
(png_byte)(pow((double)png_ptr->background.green/255, g) *
255.0 + 0.5);
back_1.blue =
(png_byte)(pow((double)png_ptr->background.blue/255, g) *
255.0 + 0.5);
}
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
png_uint_32 i;
for (i = 0; i < (png_uint_32)num_palette; i++)
{
if (i < png_ptr->num_trans && png_ptr->trans[i] == 0)
{
palette[i] = back;
}
else if (i < png_ptr->num_trans && png_ptr->trans[i] != 0xff)
{
png_byte v, w;
v = png_ptr->gamma_to_1[png_ptr->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[png_ptr->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[png_ptr->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];
}
}
}
else
{
int i;
for (i = 0; i < num_palette; i++)
{
if (palette[i].red == (png_byte)png_ptr->trans_values.gray)
{
palette[i] = back;
}
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];
}
}
}
}
else
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (png_ptr->transformations & PNG_GAMMA)
{
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
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
if (png_ptr->transformations & PNG_BACKGROUND)
{
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
png_color back;
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 < (int)png_ptr->num_trans; i++)
{
if (png_ptr->trans[i] == 0)
{
palette[i].red = back.red;
palette[i].green = back.green;
palette[i].blue = back.blue;
}
else if (png_ptr->trans[i] != 0xff)
{
png_composite(palette[i].red, png_ptr->palette[i].red,
png_ptr->trans[i], back.red);
png_composite(palette[i].green, png_ptr->palette[i].green,
png_ptr->trans[i], back.green);
png_composite(palette[i].blue, png_ptr->palette[i].blue,
png_ptr->trans[i], back.blue);
}
}
}
else /* assume grayscale palette (what else could it be?) */
{
int i;
for (i = 0; i < num_palette; i++)
{
if (i == (png_byte)png_ptr->trans_values.gray)
{
palette[i].red = (png_byte)png_ptr->background.red;
palette[i].green = (png_byte)png_ptr->background.green;
palette[i].blue = (png_byte)png_ptr->background.blue;
}
}
}
}
#endif
}
#endif
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
/* Replace any alpha or transparency with the supplied background color.
* "background" is already in the screen gamma, while "background_1" is
* at a gamma of 1.0. Paletted files have already been taken care of.
*/
void /* PRIVATE */
png_do_background(png_row_infop row_info, png_bytep row,
png_color_16p trans_values, png_color_16p background
#if defined(PNG_READ_GAMMA_SUPPORTED)
, png_color_16p background_1,
png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1,
png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1,
png_uint_16pp gamma_16_to_1, int gamma_shift
#endif
)
{
png_bytep sp, dp;
png_uint_32 i;
png_uint_32 row_width=row_info->width;
int shift;
png_debug(1, "in png_do_backgroundn");
if (background != NULL &&
#if defined(PNG_USELESS_TESTS_SUPPORTED)
row != NULL && row_info != NULL &&
#endif
(!(row_info->color_type & PNG_COLOR_MASK_ALPHA) ||
(row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_values)))
{
switch (row_info->color_type)
{
case PNG_COLOR_TYPE_GRAY:
{
switch (row_info->bit_depth)
{
case 1:
{
sp = row;
shift = 7;
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x01)
== trans_values->gray)
{
*sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
*sp |= (png_byte)(background->gray << shift);
}
if (!shift)
{
shift = 7;
sp++;
}
else
shift--;
}
break;
}
case 2:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_table != NULL)
{
sp = row;
shift = 6;
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x03)
== trans_values->gray)
{
*sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
*sp |= (png_byte)(background->gray << shift);
}
else
{
png_byte p = (png_byte)((*sp >> shift) & 0x03);
png_byte g = (png_byte)((gamma_table [p | (p << 2) |
(p << 4) | (p << 6)] >> 6) & 0x03);
*sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
*sp |= (png_byte)(g << shift);
}
if (!shift)
{
shift = 6;
sp++;
}
else
shift -= 2;
}
}
else
#endif
{
sp = row;
shift = 6;
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x03)
== trans_values->gray)
{
*sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
*sp |= (png_byte)(background->gray << shift);
}
if (!shift)
{
shift = 6;
sp++;
}
else
shift -= 2;
}
}
break;
}
case 4:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_table != NULL)
{
sp = row;
shift = 4;
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x0f)
== trans_values->gray)
{
*sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
*sp |= (png_byte)(background->gray << shift);
}
else
{
png_byte p = (png_byte)((*sp >> shift) & 0x0f);
png_byte g = (png_byte)((gamma_table[p |
(p << 4)] >> 4) & 0x0f);
*sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
*sp |= (png_byte)(g << shift);
}
if (!shift)
{
shift = 4;
sp++;
}
else
shift -= 4;
}
}
else
#endif
{
sp = row;
shift = 4;
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x0f)
== trans_values->gray)
{
*sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
*sp |= (png_byte)(background->gray << shift);
}
if (!shift)
{
shift = 4;
sp++;
}
else
shift -= 4;
}
}
break;
}
case 8:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_table != NULL)
{
sp = row;
for (i = 0; i < row_width; i++, sp++)
{
if (*sp == trans_values->gray)
{
*sp = (png_byte)background->gray;
}
else
{
*sp = gamma_table[*sp];
}
}
}
else
#endif
{
sp = row;
for (i = 0; i < row_width; i++, sp++)
{
if (*sp == trans_values->gray)
{
*sp = (png_byte)background->gray;
}
}
}
break;
}
case 16:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_16 != NULL)
{
sp = row;
for (i = 0; i < row_width; i++, sp += 2)
{
png_uint_16 v;
v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
if (v == trans_values->gray)
{
/* background is already in screen gamma */
*sp = (png_byte)((background->gray >> 8) & 0xff);
*(sp + 1) = (png_byte)(background->gray & 0xff);
}
else
{
v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
*sp = (png_byte)((v >> 8) & 0xff);
*(sp + 1) = (png_byte)(v & 0xff);
}
}
}
else
#endif
{
sp = row;
for (i = 0; i < row_width; i++, sp += 2)
{
png_uint_16 v;
v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
if (v == trans_values->gray)
{
*sp = (png_byte)((background->gray >> 8) & 0xff);
*(sp + 1) = (png_byte)(background->gray & 0xff);
}
}
}
break;
}
}
break;
}
case PNG_COLOR_TYPE_RGB:
{
if (row_info->bit_depth == 8)
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_table != NULL)
{
sp = row;
for (i = 0; i < row_width; i++, sp += 3)
{
if (*sp == trans_values->red &&
*(sp + 1) == trans_values->green &&
*(sp + 2) == trans_values->blue)
{
*sp = (png_byte)background->red;
*(sp + 1) = (png_byte)background->green;
*(sp + 2) = (png_byte)background->blue;
}
else
{
*sp = gamma_table[*sp];
*(sp + 1) = gamma_table[*(sp + 1)];
*(sp + 2) = gamma_table[*(sp + 2)];
}
}
}
else
#endif
{
sp = row;
for (i = 0; i < row_width; i++, sp += 3)
{
if (*sp == trans_values->red &&
*(sp + 1) == trans_values->green &&
*(sp + 2) == trans_values->blue)
{
*sp = (png_byte)background->red;
*(sp + 1) = (png_byte)background->green;
*(sp + 2) = (png_byte)background->blue;
}
}
}
}
else /* if (row_info->bit_depth == 16) */
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_16 != NULL)
{
sp = row;
for (i = 0; i < row_width; i++, sp += 6)
{
png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5));
if (r == trans_values->red && g == trans_values->green &&
b == trans_values->blue)
{
/* background is already in screen gamma */
*sp = (png_byte)((background->red >> 8) & 0xff);
*(sp + 1) = (png_byte)(background->red & 0xff);
*(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
*(sp + 3) = (png_byte)(background->green & 0xff);
*(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
*(sp + 5) = (png_byte)(background->blue & 0xff);
}
else
{
png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
*sp = (png_byte)((v >> 8) & 0xff);
*(sp + 1) = (png_byte)(v & 0xff);
v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
*(sp + 2) = (png_byte)((v >> 8) & 0xff);
*(sp + 3) = (png_byte)(v & 0xff);
v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
*(sp + 4) = (png_byte)((v >> 8) & 0xff);
*(sp + 5) = (png_byte)(v & 0xff);
}
}
}
else
#endif
{
sp = row;
for (i = 0; i < row_width; i++, sp += 6)
{
png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp+1));
png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5));
if (r == trans_values->red && g == trans_values->green &&
b == trans_values->blue)
{
*sp = (png_byte)((background->red >> 8) & 0xff);
*(sp + 1) = (png_byte)(background->red & 0xff);
*(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
*(sp + 3) = (png_byte)(background->green & 0xff);
*(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
*(sp + 5) = (png_byte)(background->blue & 0xff);
}
}
}
}
break;
}
case PNG_COLOR_TYPE_GRAY_ALPHA:
{
if (row_info->bit_depth == 8)
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
gamma_table != NULL)
{
sp = row;
dp = row;
for (i = 0; i < row_width; i++, sp += 2, dp++)
{
png_uint_16 a = *(sp + 1);
if (a == 0xff)
{
*dp = gamma_table[*sp];
}
else if (a == 0)
{
/* background is already in screen gamma */
*dp = (png_byte)background->gray;
}
else
{
png_byte v, w;
v = gamma_to_1[*sp];
png_composite(w, v, a, background_1->gray);
*dp = gamma_from_1[w];
}
}
}
else
#endif
{
sp = row;
dp = row;
for (i = 0; i < row_width; i++, sp += 2, dp++)
{
png_byte a = *(sp + 1);
if (a == 0xff)
{
*dp = *sp;
}
#if defined(PNG_READ_GAMMA_SUPPORTED)
else if (a == 0)
{
*dp = (png_byte)background->gray;
}
else
{
png_composite(*dp, *sp, a, background_1->gray);
}
#else
*dp = (png_byte)background->gray;
#endif
}
}
}
else /* if (png_ptr->bit_depth == 16) */
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
gamma_16_to_1 != NULL)
{
sp = row;
dp = row;
for (i = 0; i < row_width; i++, sp += 4, dp += 2)
{
png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
if (a == (png_uint_16)0xffff)
{
png_uint_16 v;
v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
*dp = (png_byte)((v >> 8) & 0xff);
*(dp + 1) = (png_byte)(v & 0xff);
}
#if defined(PNG_READ_GAMMA_SUPPORTED)
else if (a == 0)
#else
else
#endif
{
/* background is already in screen gamma */
*dp = (png_byte)((background->gray >> 8) & 0xff);
*(dp + 1) = (png_byte)(background->gray & 0xff);
}
#if defined(PNG_READ_GAMMA_SUPPORTED)
else
{
png_uint_16 g, v, w;
g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
png_composite_16(v, g, a, background_1->gray);
w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
*dp = (png_byte)((w >> 8) & 0xff);
*(dp + 1) = (png_byte)(w & 0xff);
}
#endif
}
}
else
#endif
{
sp = row;
dp = row;
for (i = 0; i < row_width; i++, sp += 4, dp += 2)
{
png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
if (a == (png_uint_16)0xffff)
{
png_memcpy(dp, sp, 2);
}
#if defined(PNG_READ_GAMMA_SUPPORTED)
else if (a == 0)
#else
else
#endif
{
*dp = (png_byte)((background->gray >> 8) & 0xff);
*(dp + 1) = (png_byte)(background->gray & 0xff);
}
#if defined(PNG_READ_GAMMA_SUPPORTED)
else
{
png_uint_16 g, v;
g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
png_composite_16(v, g, a, background_1->gray);
*dp = (png_byte)((v >> 8) & 0xff);
*(dp + 1) = (png_byte)(v & 0xff);
}
#endif
}
}
}
break;
}
case PNG_COLOR_TYPE_RGB_ALPHA:
{
if (row_info->bit_depth == 8)
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
gamma_table != NULL)
{
sp = row;
dp = row;
for (i = 0; i < row_width; i++, sp += 4, dp += 3)
{
png_byte a = *(sp + 3);
if (a == 0xff)
{
*dp = gamma_table[*sp];
*(dp + 1) = gamma_table[*(sp + 1)];
*(dp + 2) = gamma_table[*(sp + 2)];
}
else if (a == 0)
{
/* background is already in screen gamma */
*dp = (png_byte)background->red;
*(dp + 1) = (png_byte)background->green;
*(dp + 2) = (png_byte)background->blue;
}
else
{
png_byte v, w;
v = gamma_to_1[*sp];
png_composite(w, v, a, background_1->red);
*dp = gamma_from_1[w];
v = gamma_to_1[*(sp + 1)];
png_composite(w, v, a, background_1->green);
*(dp + 1) = gamma_from_1[w];
v = gamma_to_1[*(sp + 2)];
png_composite(w, v, a, background_1->blue);
*(dp + 2) = gamma_from_1[w];
}
}
}
else
#endif
{
sp = row;
dp = row;
for (i = 0; i < row_width; i++, sp += 4, dp += 3)
{
png_byte a = *(sp + 3);
if (a == 0xff)
{
*dp = *sp;
*(dp + 1) = *(sp + 1);
*(dp + 2) = *(sp + 2);
}
else if (a == 0)
{
*dp = (png_byte)background->red;
*(dp + 1) = (png_byte)background->green;
*(dp + 2) = (png_byte)background->blue;
}
else
{
png_composite(*dp, *sp, a, background->red);
png_composite(*(dp + 1), *(sp + 1), a,
background->green);
png_composite(*(dp + 2), *(sp + 2), a,
background->blue);
}
}
}
}
else /* if (row_info->bit_depth == 16) */
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
gamma_16_to_1 != NULL)
{
sp = row;
dp = row;
for (i = 0; i < row_width; i++, sp += 8, dp += 6)
{
png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
<< 8) + (png_uint_16)(*(sp + 7)));
if (a == (png_uint_16)0xffff)
{
png_uint_16 v;
v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
*dp = (png_byte)((v >> 8) & 0xff);
*(dp + 1) = (png_byte)(v & 0xff);
v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
*(dp + 2) = (png_byte)((v >> 8) & 0xff);
*(dp + 3) = (png_byte)(v & 0xff);
v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
*(dp + 4) = (png_byte)((v >> 8) & 0xff);
*(dp + 5) = (png_byte)(v & 0xff);
}
else if (a == 0)
{
/* background is already in screen gamma */
*dp = (png_byte)((background->red >> 8) & 0xff);
*(dp + 1) = (png_byte)(background->red & 0xff);
*(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
*(dp + 3) = (png_byte)(background->green & 0xff);
*(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
*(dp + 5) = (png_byte)(background->blue & 0xff);
}
else
{
png_uint_16 v, w, x;
v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
png_composite_16(w, v, a, background_1->red);
x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
*dp = (png_byte)((x >> 8) & 0xff);
*(dp + 1) = (png_byte)(x & 0xff);
v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
png_composite_16(w, v, a, background_1->green);
x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
*(dp + 2) = (png_byte)((x >> 8) & 0xff);
*(dp + 3) = (png_byte)(x & 0xff);
v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
png_composite_16(w, v, a, background_1->blue);
x = gamma_16_from_1[(w & 0xff) >> gamma_shift][w >> 8];
*(dp + 4) = (png_byte)((x >> 8) & 0xff);
*(dp + 5) = (png_byte)(x & 0xff);
}
}
}
else
#endif
{
sp = row;
dp = row;
for (i = 0; i < row_width; i++, sp += 8, dp += 6)
{
png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
<< 8) + (png_uint_16)(*(sp + 7)));
if (a == (png_uint_16)0xffff)
{
png_memcpy(dp, sp, 6);
}
else if (a == 0)
{
*dp = (png_byte)((background->red >> 8) & 0xff);
*(dp + 1) = (png_byte)(background->red & 0xff);
*(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
*(dp + 3) = (png_byte)(background->green & 0xff);
*(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
*(dp + 5) = (png_byte)(background->blue & 0xff);
}
else
{
png_uint_16 v;
png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+ *(sp + 3));
png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+ *(sp + 5));
png_composite_16(v, r, a, background->red);
*dp = (png_byte)((v >> 8) & 0xff);
*(dp + 1) = (png_byte)(v & 0xff);
png_composite_16(v, g, a, background->green);
*(dp + 2) = (png_byte)((v >> 8) & 0xff);
*(dp + 3) = (png_byte)(v & 0xff);
png_composite_16(v, b, a, background->blue);
*(dp + 4) = (png_byte)((v >> 8) & 0xff);
*(dp + 5) = (png_byte)(v & 0xff);
}
}
}
}
break;
}
}
if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
{
row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
row_info->channels--;
row_info->pixel_depth = (png_byte)(row_info->channels *
row_info->bit_depth);
row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
}
}
}
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED)
/* Gamma correct the image, avoiding the alpha channel. Make sure
* you do this after you deal with the transparency issue on grayscale
* or RGB images. If your bit depth is 8, use gamma_table, if it
* is 16, use gamma_16_table and gamma_shift. Build these with
* build_gamma_table().
*/
void /* PRIVATE */
png_do_gamma(png_row_infop row_info, png_bytep row,
png_bytep gamma_table, png_uint_16pp gamma_16_table,
int gamma_shift)
{
png_bytep sp;
png_uint_32 i;
png_uint_32 row_width=row_info->width;
png_debug(1, "in png_do_gamman");
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;
}
}
}
}
#endif
#if defined(PNG_READ_EXPAND_SUPPORTED)
/* Expands a palette row to an RGB or RGBA row depending
* upon whether you supply trans and num_trans.
*/
void /* PRIVATE */
png_do_expand_palette(png_row_infop row_info, png_bytep row,
png_colorp palette, png_bytep trans, int num_trans)
{
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_paletten");
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;
}
}
}
}
/* If the bit depth < 8, it is expanded to 8. Also, if the
* transparency value is supplied, an alpha channel is built.
*/
void /* PRIVATE */
png_do_expand(png_row_infop row_info, png_bytep row,
png_color_16p trans_value)
{
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_expandn");
#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);
}
}
}
#endif
#if defined(PNG_READ_DITHER_SUPPORTED)
void /* PRIVATE */
png_do_dither(png_row_infop row_info, png_bytep row,
png_bytep palette_lookup, png_bytep dither_lookup)
{
png_bytep sp, dp;
png_uint_32 i;
png_uint_32 row_width=row_info->width;
png_debug(1, "in png_do_dithern");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
if (row != NULL && row_info != NULL)
#endif
{
if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
palette_lookup && row_info->bit_depth == 8)
{
int r, g, b, p;
sp = row;
dp = row;
for (i = 0; i < row_width; i++)
{
r = *sp++;
g = *sp++;
b = *sp++;
/* this looks real messy, but the compiler will reduce
it down to a reasonable formula. For example, with
5 bits per color, we get:
p = (((r >> 3) & 0x1f) << 10) |
(((g >> 3) & 0x1f) << 5) |
((b >> 3) & 0x1f);
*/
p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
((1 << PNG_DITHER_RED_BITS) - 1)) <<
(PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
(((g >> (8 - PNG_DITHER_GREEN_BITS)) &
((1 << PNG_DITHER_GREEN_BITS) - 1)) <<
(PNG_DITHER_BLUE_BITS)) |
((b >> (8 - PNG_DITHER_BLUE_BITS)) &
((1 << PNG_DITHER_BLUE_BITS) - 1));
*dp++ = palette_lookup[p];
}
row_info->color_type = PNG_COLOR_TYPE_PALETTE;
row_info->channels = 1;
row_info->pixel_depth = row_info->bit_depth;
row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
}
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
palette_lookup != NULL && row_info->bit_depth == 8)
{
int r, g, b, p;
sp = row;
dp = row;
for (i = 0; i < row_width; i++)
{
r = *sp++;
g = *sp++;
b = *sp++;
sp++;
p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
((1 << PNG_DITHER_RED_BITS) - 1)) <<
(PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
(((g >> (8 - PNG_DITHER_GREEN_BITS)) &
((1 << PNG_DITHER_GREEN_BITS) - 1)) <<
(PNG_DITHER_BLUE_BITS)) |
((b >> (8 - PNG_DITHER_BLUE_BITS)) &
((1 << PNG_DITHER_BLUE_BITS) - 1));
*dp++ = palette_lookup[p];
}
row_info->color_type = PNG_COLOR_TYPE_PALETTE;
row_info->channels = 1;
row_info->pixel_depth = row_info->bit_depth;
row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
}
else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
dither_lookup && row_info->bit_depth == 8)
{
sp = row;
for (i = 0; i < row_width; i++, sp++)
{
*sp = dither_lookup[*sp];
}
}
}
}
#endif
#ifdef PNG_FLOATING_POINT_SUPPORTED
#if defined(PNG_READ_GAMMA_SUPPORTED)
static int png_gamma_shift[] =
{0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0};
/* We build the 8- or 16-bit gamma tables here. Note that for 16-bit
* tables, we don't make a full table if we are reducing to 8-bit in
* the future. Note also how the gamma_16 tables are segmented so that
* we don't need to allocate > 64K chunks for a full 16-bit table.
*/
void /* PRIVATE */
png_build_gamma_table(png_structp png_ptr)
{
png_debug(1, "in png_build_gamma_tablen");
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 */
}
}
}
#endif
/* To do: install integer version of png_build_gamma_table here */
#endif
#if defined(PNG_MNG_FEATURES_SUPPORTED)
/* undoes intrapixel differencing */
void /* PRIVATE */
png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_read_intrapixeln");
if (
#if defined(PNG_USELESS_TESTS_SUPPORTED)
row != NULL && row_info != NULL &&
#endif
(row_info->color_type & PNG_COLOR_MASK_COLOR))
{
int bytes_per_pixel;
png_uint_32 row_width = row_info->width;
if (row_info->bit_depth == 8)
{
png_bytep rp;
png_uint_32 i;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 3;
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 4;
else
return;
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
*(rp) = (png_byte)((256 + *rp + *(rp+1))&0xff);
*(rp+2) = (png_byte)((256 + *(rp+2) + *(rp+1))&0xff);
}
}
else if (row_info->bit_depth == 16)
{
png_bytep rp;
png_uint_32 i;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 6;
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 8;
else
return;
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
png_uint_32 s0 = (*(rp ) << 8) | *(rp+1);
png_uint_32 s1 = (*(rp+2) << 8) | *(rp+3);
png_uint_32 s2 = (*(rp+4) << 8) | *(rp+5);
png_uint_32 red = (png_uint_32)((s0+s1+65536L) & 0xffffL);
png_uint_32 blue = (png_uint_32)((s2+s1+65536L) & 0xffffL);
*(rp ) = (png_byte)((red >> 8) & 0xff);
*(rp+1) = (png_byte)(red & 0xff);
*(rp+4) = (png_byte)((blue >> 8) & 0xff);
*(rp+5) = (png_byte)(blue & 0xff);
}
}
}
}
#endif /* PNG_MNG_FEATURES_SUPPORTED */