This is pngrtran.c in view mode; [Download] [Up]
/* pngrtran.c - transforms the data in a row for png readers
libpng 1.0 beta 3 - version 0.89
For conditions of distribution and use, see copyright notice in png.h
Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
May 25, 1996
*/
#define PNG_INTERNAL
#include "png.h"
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
/* handle alpha and tRNS via a background color */
void
png_set_background(png_structp png_ptr,
png_color_16p background_color, int background_gamma_code,
int need_expand, double background_gamma)
{
png_ptr->transformations |= PNG_BACKGROUND;
png_memcpy(&(png_ptr->background), background_color,
sizeof(png_color_16));
png_ptr->background_gamma = (float)background_gamma;
png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0);
}
#endif
#if defined(PNG_READ_16_TO_8_SUPPORTED)
/* strip 16 bit depth files to 8 bit depth */
void
png_set_strip_16(png_structp png_ptr)
{
png_ptr->transformations |= PNG_16_TO_8;
}
#endif
#if defined(PNG_READ_DITHER_SUPPORTED)
/* dither file to 8 bit. Supply a palette, the current number
of elements in the palette, the maximum number of elements
allowed, and a histogram, if possible. If the current number
is greater then the maximum number, the palette will be
modified to fit in the maximum number */
typedef struct png_dsort_struct
{
struct png_dsort_struct FAR * next;
png_byte left;
png_byte right;
} png_dsort;
typedef png_dsort FAR * png_dsortp;
typedef png_dsort FAR * FAR * png_dsortpp;
void
png_set_dither(png_structp png_ptr, png_colorp palette,
int num_palette, int maximum_colors, png_uint_16p histogram,
int full_dither)
{
png_ptr->transformations |= PNG_DITHER;
if (!full_dither)
{
int i;
png_ptr->dither_index = (png_bytep)png_large_malloc(png_ptr,
num_palette * sizeof (png_byte));
for (i = 0; i < num_palette; i++)
png_ptr->dither_index[i] = (png_byte)i;
}
if (num_palette > maximum_colors)
{
if (histogram)
{
/* this is easy enough, just throw out the least used colors.
perhaps not the best solution, but good enough */
int i;
png_bytep sort;
/* initialize an array to sort colors */
sort = (png_bytep)png_large_malloc(png_ptr, num_palette * sizeof (png_byte));
/* initialize the sort array */
for (i = 0; i < num_palette; i++)
sort[i] = (png_byte)i;
/* find the least used palette entries by starting a
bubble sort, and running it until we have sorted
out enough colors. Note that we don't care about
sorting all the colors, just finding which are
least used. */
for (i = num_palette - 1; i >= maximum_colors; i--)
{
int done; /* to stop early if the list is pre-sorted */
int j;
done = 1;
for (j = 0; j < i; j++)
{
if (histogram[sort[j]] < histogram[sort[j + 1]])
{
png_byte t;
t = sort[j];
sort[j] = sort[j + 1];
sort[j + 1] = t;
done = 0;
}
}
if (done)
break;
}
/* swap the palette around, and set up a table, if necessary */
if (full_dither)
{
int j;
/* put all the useful colors within the max, but don't
move the others */
j = num_palette;
for (i = 0; i < maximum_colors; i++)
{
if (sort[i] >= maximum_colors)
{
do
j--;
while (sort[j] >= maximum_colors);
palette[i] = palette[j];
}
}
}
else
{
int j;
/* move all the used colors inside the max limit, and
develop a translation table */
j = num_palette;
for (i = 0; i < maximum_colors; i++)
{
/* only move the colors we need to */
if (sort[i] >= maximum_colors)
{
png_color tmp_color;
do
j--;
while (sort[j] >= maximum_colors);
tmp_color = palette[j];
palette[j] = palette[i];
palette[i] = tmp_color;
/* indicate where the color went */
png_ptr->dither_index[j] = (png_byte)i;
png_ptr->dither_index[i] = (png_byte)j;
}
}
/* find closest color for those colors we are not
using */
for (i = 0; i < num_palette; i++)
{
if (png_ptr->dither_index[i] >= maximum_colors)
{
int min_d, j, min_j, index;
/* find the closest color to one we threw out */
index = png_ptr->dither_index[i];
min_d = PNG_COLOR_DIST(palette[index],
palette[0]);
min_j = 0;
for (j = 1; j < maximum_colors; j++)
{
int d;
d = PNG_COLOR_DIST(palette[index],
palette[j]);
if (d < min_d)
{
min_d = d;
min_j = j;
}
}
/* point to closest color */
png_ptr->dither_index[i] = (png_byte)min_j;
}
}
}
png_large_free(png_ptr, sort);
}
else
{
/* this is much harder to do simply (and quickly). Perhaps
we need to go through a median cut routine, but those
don't always behave themselves with only a few colors
as input. So we will just find the closest two colors,
and throw out one of them (chosen somewhat randomly).
*/
int i;
int max_d;
int num_new_palette;
png_dsortpp hash;
png_bytep index_to_palette;
/* where the original index currently is in the palette */
png_bytep palette_to_index;
/* which original index points to this palette color */
/* initialize palette index arrays */
index_to_palette = (png_bytep)png_large_malloc(png_ptr,
num_palette * sizeof (png_byte));
palette_to_index = (png_bytep)png_large_malloc(png_ptr,
num_palette * sizeof (png_byte));
/* initialize the sort array */
for (i = 0; i < num_palette; i++)
{
index_to_palette[i] = (png_byte)i;
palette_to_index[i] = (png_byte)i;
}
hash = (png_dsortpp)png_large_malloc(png_ptr, 769 * sizeof (png_dsortp));
for (i = 0; i < 769; i++)
hash[i] = (png_dsortp)0;
/* png_memset(hash, 0, 769 * sizeof (png_dsortp)); */
num_new_palette = num_palette;
/* initial wild guess at how far apart the farthest pixel
pair we will be eliminating will be. Larger
numbers mean more areas will be allocated, Smaller
numbers run the risk of not saving enough data, and
having to do this all over again.
I have not done extensive checking on this number.
*/
max_d = 96;
while (num_new_palette > maximum_colors)
{
for (i = 0; i < num_new_palette - 1; i++)
{
int j;
for (j = i + 1; j < num_new_palette; j++)
{
int d;
d = PNG_COLOR_DIST(palette[i], palette[j]);
if (d <= max_d)
{
png_dsortp t;
t = png_large_malloc(png_ptr, sizeof (png_dsort));
t->next = hash[d];
t->left = (png_byte)i;
t->right = (png_byte)j;
hash[d] = t;
}
}
}
for (i = 0; i <= max_d; i++)
{
if (hash[i])
{
png_dsortp p;
for (p = hash[i]; p; p = p->next)
{
if (index_to_palette[p->left] < num_new_palette &&
index_to_palette[p->right] < num_new_palette)
{
int j, next_j;
if (num_new_palette & 1)
{
j = p->left;
next_j = p->right;
}
else
{
j = p->right;
next_j = p->left;
}
num_new_palette--;
palette[index_to_palette[j]] =
palette[num_new_palette];
if (!full_dither)
{
int k;
for (k = 0; k < num_palette; k++)
{
if (png_ptr->dither_index[k] ==
index_to_palette[j])
png_ptr->dither_index[k] =
index_to_palette[next_j];
if (png_ptr->dither_index[k] ==
num_new_palette)
png_ptr->dither_index[k] =
index_to_palette[j];
}
}
index_to_palette[palette_to_index[num_new_palette]] =
index_to_palette[j];
palette_to_index[index_to_palette[j]] =
palette_to_index[num_new_palette];
index_to_palette[j] = (png_byte)num_new_palette;
palette_to_index[num_new_palette] = (png_byte)j;
}
if (num_new_palette <= maximum_colors)
break;
}
if (num_new_palette <= maximum_colors)
break;
}
}
for (i = 0; i < 769; i++)
{
if (hash[i])
{
png_dsortp p;
p = hash[i];
while (p)
{
png_dsortp t;
t = p->next;
png_large_free(png_ptr, p);
p = t;
}
}
hash[i] = 0;
}
max_d += 96;
}
png_large_free(png_ptr, hash);
png_large_free(png_ptr, palette_to_index);
png_large_free(png_ptr, index_to_palette);
}
num_palette = maximum_colors;
}
if (!(png_ptr->palette))
{
png_ptr->palette = palette;
}
png_ptr->num_palette = (png_uint_16)num_palette;
if (full_dither)
{
int i;
int total_bits, num_red, num_green, num_blue;
png_uint_32 num_entries;
png_bytep distance;
total_bits = PNG_DITHER_RED_BITS + PNG_DITHER_GREEN_BITS +
PNG_DITHER_BLUE_BITS;
num_red = (1 << PNG_DITHER_RED_BITS);
num_green = (1 << PNG_DITHER_GREEN_BITS);
num_blue = (1 << PNG_DITHER_BLUE_BITS);
num_entries = ((png_uint_32)1 << total_bits);
png_ptr->palette_lookup = (png_bytep )png_large_malloc(png_ptr,
(png_size_t)num_entries * sizeof (png_byte));
png_memset(png_ptr->palette_lookup, 0, (png_size_t)num_entries * sizeof (png_byte));
distance = (png_bytep )png_large_malloc(png_ptr,
(png_size_t)num_entries * sizeof (png_byte));
png_memset(distance, 0xff, (png_size_t)num_entries * sizeof (png_byte));
for (i = 0; i < num_palette; i++)
{
int r, g, b, ir, ig, ib;
r = (palette[i].red >> (8 - PNG_DITHER_RED_BITS));
g = (palette[i].green >> (8 - PNG_DITHER_GREEN_BITS));
b = (palette[i].blue >> (8 - PNG_DITHER_BLUE_BITS));
for (ir = 0; ir < num_red; ir++)
{
int dr, index_r;
dr = abs(ir - r);
index_r = (ir << (PNG_DITHER_BLUE_BITS + PNG_DITHER_GREEN_BITS));
for (ig = 0; ig < num_green; ig++)
{
int dg, dt, dm, index_g;
dg = abs(ig - g);
dt = dr + dg;
dm = ((dr > dg) ? dr : dg);
index_g = index_r | (ig << PNG_DITHER_BLUE_BITS);
for (ib = 0; ib < num_blue; ib++)
{
int index, db, dmax, d;
index = index_g | ib;
db = abs(ib - b);
dmax = ((dm > db) ? dm : db);
d = dmax + dt + db;
if (d < distance[index])
{
distance[index] = (png_byte)d;
png_ptr->palette_lookup[index] = (png_byte)i;
}
}
}
}
}
png_large_free(png_ptr, distance);
}
}
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED)
/* transform the image from the file_gamma to the screen_gamma */
void
png_set_gamma(png_structp png_ptr, double screen_gamma,
double file_gamma)
{
png_ptr->transformations |= PNG_GAMMA;
png_ptr->gamma = (float)file_gamma;
png_ptr->display_gamma = (float)screen_gamma;
}
#endif
#if defined(PNG_READ_EXPAND_SUPPORTED)
/* expand paletted images to rgb, expand grayscale images of
less then 8 bit depth to 8 bit depth, and expand tRNS chunks
to alpha channels */
void
png_set_expand(png_structp png_ptr)
{
png_ptr->transformations |= PNG_EXPAND;
}
#endif
#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
void
png_set_gray_to_rgb(png_structp png_ptr)
{
png_ptr->transformations |= PNG_GRAY_TO_RGB;
}
#endif
/* initialize everything needed for the read. This includes modifying
the palette */
void
png_init_read_transformations(png_structp png_ptr)
{
int color_type;
color_type = png_ptr->color_type;
#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
if (png_ptr->transformations & PNG_BACKGROUND_EXPAND)
{
if (color_type == PNG_COLOR_TYPE_GRAY)
{
/* 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;
}
}
#endif
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
png_ptr->background_1 = png_ptr->background;
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (png_ptr->transformations & PNG_GAMMA)
{
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)
{
int num_palette, i;
png_color back, back_1;
png_colorp palette;
palette = png_ptr->palette;
num_palette = png_ptr->num_palette;
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];
for (i = 0; i < num_palette; i++)
{
if (i < (int)png_ptr->num_trans)
{
if (png_ptr->trans[i] == 0)
{
palette[i] = back;
}
else if (png_ptr->trans[i] != 0xff)
{
int v, w;
v = png_ptr->gamma_to_1[palette[i].red];
w = (int)(((png_uint_32)(v) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back_1.red) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
palette[i].red = png_ptr->gamma_from_1[w];
v = png_ptr->gamma_to_1[palette[i].green];
w = (int)(((png_uint_32)(v) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back_1.green) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
palette[i].green = png_ptr->gamma_from_1[w];
v = png_ptr->gamma_to_1[palette[i].blue];
w = (int)(((png_uint_32)(v) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back_1.blue) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
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 if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN)
{
double g, gs, m;
m = (double)(((png_uint_32)1 << png_ptr->bit_depth) - 1);
g = 1.0;
gs = 1.0;
switch (png_ptr->background_gamma_type)
{
case PNG_BACKGROUND_GAMMA_SCREEN:
g = (png_ptr->display_gamma);
gs = 1.0;
break;
case PNG_BACKGROUND_GAMMA_FILE:
g = 1.0 / (png_ptr->gamma);
gs = 1.0 / (png_ptr->gamma * png_ptr->display_gamma);
break;
case PNG_BACKGROUND_GAMMA_UNIQUE:
g = 1.0 / (png_ptr->background_gamma);
gs = 1.0 / (png_ptr->background_gamma *
png_ptr->display_gamma);
break;
}
if (color_type & PNG_COLOR_MASK_COLOR)
{
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
{
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);
}
}
}
else
#endif
if (color_type == PNG_COLOR_TYPE_PALETTE)
{
int num_palette, i;
png_colorp palette;
palette = png_ptr->palette;
num_palette = png_ptr->num_palette;
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 &&
color_type == PNG_COLOR_TYPE_PALETTE)
{
int i;
png_color back;
png_colorp palette;
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 < png_ptr->num_trans; i++)
{
if (png_ptr->trans[i] == 0)
{
palette[i] = back;
}
else if (png_ptr->trans[i] != 0xff)
{
palette[i].red = (png_byte)((
(png_uint_32)(palette[i].red) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back.red) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
palette[i].green = (png_byte)((
(png_uint_32)(palette[i].green) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back.green) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
palette[i].blue = (png_byte)((
(png_uint_32)(palette[i].blue) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back.blue) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
}
}
}
#endif
#if defined(PNG_READ_SHIFT_SUPPORTED)
if ((png_ptr->transformations & PNG_SHIFT) &&
color_type == PNG_COLOR_TYPE_PALETTE)
{
png_uint_16 i;
int sr, sg, sb;
sr = 8 - png_ptr->sig_bit.red;
if (sr < 0 || sr > 8)
sr = 0;
sg = 8 - png_ptr->sig_bit.green;
if (sg < 0 || sg > 8)
sg = 0;
sb = 8 - png_ptr->sig_bit.blue;
if (sb < 0 || sb > 8)
sb = 0;
for (i = 0; i < png_ptr->num_palette; i++)
{
png_ptr->palette[i].red >>= sr;
png_ptr->palette[i].green >>= sg;
png_ptr->palette[i].blue >>= sb;
}
}
#endif
}
/* modify the info structure to reflect the transformations. The
info should be updated so a png file could be written with it,
assuming the transformations result in valid png data */
void
png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
{
#if defined(PNG_READ_EXPAND_SUPPORTED)
if ((png_ptr->transformations & PNG_EXPAND) &&
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->transformations & PNG_EXPAND)
{
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_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))
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 (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
info_ptr->channels++;
info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
info_ptr->bit_depth);
info_ptr->rowbytes = ((info_ptr->width * info_ptr->pixel_depth + 7) >> 3);
}
/* transform the row. The order of transformations is significant,
and is very touchy. If you add a transformation, take care to
decide how it fits in with the other transformations here */
void
png_do_read_transformations(png_structp png_ptr)
{
#if defined(PNG_READ_EXPAND_SUPPORTED)
if ((png_ptr->transformations & PNG_EXPAND) &&
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->transformations & PNG_EXPAND)
{
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_BACKGROUND_SUPPORTED)
if (png_ptr->transformations & PNG_BACKGROUND)
png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1,
&(png_ptr->trans_values), &(png_ptr->background),
&(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
#if defined(PNG_READ_GAMMA_SUPPORTED)
if ((png_ptr->transformations & PNG_GAMMA) &&
!(png_ptr->transformations & PNG_BACKGROUND))
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);
}
#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_GRAY_TO_RGB_SUPPORTED)
if (png_ptr->transformations & PNG_GRAY_TO_RGB)
png_do_gray_to_rgb(&(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_FILLER_SUPPORTED)
if (png_ptr->transformations & PNG_FILLER)
png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
png_ptr->filler, png_ptr->flags);
#endif
}
#if defined(PNG_READ_PACK_SUPPORTED)
/* unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
without changing the actual values. Thus, if you had a row with
a bit depth of 1, you would end up with bytes that only contained
the numbers 0 or 1. If you would rather they contain 0 and 255, use
png_do_shift() after this. */
void
png_do_unpack(png_row_infop row_info, png_bytep row)
{
int shift;
png_bytep sp, dp;
png_uint_32 i;
if (row && row_info && row_info->bit_depth < 8)
{
switch (row_info->bit_depth)
{
case 1:
{
sp = row + (png_size_t)((row_info->width - 1) >> 3);
dp = row + (png_size_t)row_info->width - 1;
shift = 7 - (int)((row_info->width + 7) & 7);
for (i = 0; i < row_info->width; i++)
{
*dp = (png_byte)((*sp >> shift) & 0x1);
if (shift == 7)
{
shift = 0;
sp--;
}
else
shift++;
dp--;
}
break;
}
case 2:
{
sp = row + (png_size_t)((row_info->width - 1) >> 2);
dp = row + (png_size_t)row_info->width - 1;
shift = (int)((3 - ((row_info->width + 3) & 3)) << 1);
for (i = 0; i < row_info->width; i++)
{
*dp = (png_byte)((*sp >> shift) & 0x3);
if (shift == 6)
{
shift = 0;
sp--;
}
else
shift += 2;
dp--;
}
break;
}
case 4:
{
sp = row + (png_size_t)((row_info->width - 1) >> 1);
dp = row + (png_size_t)row_info->width - 1;
shift = (int)((1 - ((row_info->width + 1) & 1)) << 2);
for (i = 0; i < row_info->width; i++)
{
*dp = (png_byte)((*sp >> shift) & 0xf);
if (shift == 4)
{
shift = 0;
sp--;
}
else
shift = 4;
dp--;
}
break;
}
}
row_info->bit_depth = 8;
row_info->pixel_depth = (png_byte)(8 * row_info->channels);
row_info->rowbytes = row_info->width * row_info->channels;
}
}
#endif
#if defined(PNG_READ_SHIFT_SUPPORTED)
/* reverse the effects of png_do_shift. This routine merely shifts the
pixels back to their significant bits values. Thus, if you have
a row of bit depth 8, but only 5 are significant, this will shift
the values back to 0 through 31 */
void
png_do_unshift(png_row_infop row_info, png_bytep row,
png_color_8p sig_bits)
{
png_bytep bp;
png_uint_16 value;
png_uint_32 i;
if (row && row_info && sig_bits &&
row_info->color_type != PNG_COLOR_TYPE_PALETTE)
{
int shift[4];
int channels;
channels = 0;
if (row_info->color_type & PNG_COLOR_MASK_COLOR)
{
shift[channels++] = row_info->bit_depth - sig_bits->red;
shift[channels++] = row_info->bit_depth - sig_bits->green;
shift[channels++] = row_info->bit_depth - sig_bits->blue;
}
else
{
shift[channels++] = row_info->bit_depth - sig_bits->gray;
}
if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
{
shift[channels++] = row_info->bit_depth - sig_bits->alpha;
}
value = 0;
for (i = 0; i < channels; i++)
{
if (shift[(png_size_t)i] <= 0)
shift[(png_size_t)i] = 0;
else
value = 1;
}
if (!value)
return;
switch (row_info->bit_depth)
{
case 2:
{
for (bp = row, i = 0;
i < row_info->rowbytes;
i++, bp++)
{
*bp >>= 1;
*bp &= 0x55;
}
break;
}
case 4:
{
png_byte mask;
mask = (png_byte)(((int)0xf0 >> shift[0]) & (int)0xf0) |
(png_byte)((int)0xf >> shift[0]);
for (bp = row, i = 0;
i < row_info->rowbytes;
i++, bp++)
{
*bp >>= shift[0];
*bp &= mask;
}
break;
}
case 8:
{
for (bp = row, i = 0;
i < row_info->width; i++)
{
int c;
for (c = 0; c < row_info->channels; c++, bp++)
{
*bp >>= shift[c];
}
}
break;
}
case 16:
{
for (bp = row, i = 0;
i < row_info->width; i++)
{
int c;
for (c = 0; c < row_info->channels; c++, bp += 2)
{
value = (png_uint_16)((*bp << 8) + *(bp + 1));
value >>= shift[c];
*bp = (png_byte)(value >> 8);
*(bp + 1) = (png_byte)(value & 0xff);
}
}
break;
}
}
}
}
#endif
#if defined(PNG_READ_16_TO_8_SUPPORTED)
/* chop rows of bit depth 16 down to 8 */
void
png_do_chop(png_row_infop row_info, png_bytep row)
{
png_bytep sp, dp;
png_uint_32 i;
if (row && row_info && row_info->bit_depth == 16)
{
sp = row;
dp = row;
for (i = 0; i < row_info->width * row_info->channels; i++)
{
*dp = *sp;
/* not yet, as I'm afraid of overflow here
*dp = ((((((png_uint_16)(*sp) << 8)) |
(png_uint_16)((*(sp + 1) - *sp) & 0xff) +
0x7f) >> 8) & 0xff);
*/
sp += 2;
dp++;
}
row_info->bit_depth = 8;
row_info->pixel_depth = (png_byte)(8 * row_info->channels);
row_info->rowbytes = row_info->width * row_info->channels;
}
}
#endif
#if defined(PNG_READ_FILLER_SUPPORTED)
/* add filler byte */
void
png_do_read_filler(png_row_infop row_info, png_bytep row,
png_byte filler, png_byte flags)
{
png_bytep sp, dp;
png_uint_32 i;
if (row && row_info && row_info->color_type == 2 &&
row_info->bit_depth == 8)
{
if (flags & PNG_FLAG_FILLER_AFTER)
{
for (i = 1, sp = row + (png_size_t)row_info->width * 3,
dp = row + (png_size_t)row_info->width * 4;
i < row_info->width;
i++)
{
*(--dp) = filler;
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
}
*(--dp) = filler;
row_info->channels = 4;
row_info->pixel_depth = 32;
row_info->rowbytes = row_info->width * 4;
}
else
{
for (i = 0, sp = row + (png_size_t)row_info->width * 3,
dp = row + (png_size_t)row_info->width * 4;
i < row_info->width;
i++)
{
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = filler;
}
row_info->channels = 4;
row_info->pixel_depth = 32;
row_info->rowbytes = row_info->width * 4;
}
}
}
#endif
#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
/* expand grayscale files to rgb, with or without alpha */
void
png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
{
png_bytep sp, dp;
png_uint_32 i;
if (row && row_info && row_info->bit_depth >= 8 &&
!(row_info->color_type & PNG_COLOR_MASK_COLOR))
{
if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
{
if (row_info->bit_depth == 8)
{
for (i = 0, sp = row + (png_size_t)row_info->width - 1,
dp = row + (png_size_t)row_info->width * 3 - 1;
i < row_info->width;
i++)
{
*(dp--) = *sp;
*(dp--) = *sp;
*(dp--) = *sp;
sp--;
}
}
else
{
for (i = 0, sp = row + (png_size_t)row_info->width * 2 - 1,
dp = row + (png_size_t)row_info->width * 6 - 1;
i < row_info->width;
i++)
{
*(dp--) = *sp;
*(dp--) = *(sp - 1);
*(dp--) = *sp;
*(dp--) = *(sp - 1);
*(dp--) = *sp;
*(dp--) = *(sp - 1);
sp--;
sp--;
}
}
}
else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
{
if (row_info->bit_depth == 8)
{
for (i = 0, sp = row + (png_size_t)row_info->width * 2 - 1,
dp = row + (png_size_t)row_info->width * 4 - 1;
i < row_info->width;
i++)
{
*(dp--) = *(sp--);
*(dp--) = *sp;
*(dp--) = *sp;
*(dp--) = *sp;
sp--;
}
}
else
{
for (i = 0, sp = row + (png_size_t)row_info->width * 4 - 1,
dp = row + (png_size_t)row_info->width * 8 - 1;
i < row_info->width;
i++)
{
*(dp--) = *(sp--);
*(dp--) = *(sp--);
*(dp--) = *sp;
*(dp--) = *(sp - 1);
*(dp--) = *sp;
*(dp--) = *(sp - 1);
*(dp--) = *sp;
*(dp--) = *(sp - 1);
sp--;
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 = ((row_info->width *
row_info->pixel_depth + 7) >> 3);
}
}
#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
png_build_grayscale_palette(int bit_depth, png_colorp palette)
{
int num_palette;
int color_inc;
int i;
int v;
if (!palette)
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? */
#if defined(PNG_READ_DITHER_SUPPORTED) || defined(PNG_CORRECT_PALETTE_SUPPORTED)
void
png_correct_palette(png_structp png_ptr, png_colorp palette,
int num_palette)
{
#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
if ((png_ptr->transformations & (PNG_GAMMA)) &&
(png_ptr->transformations & (PNG_BACKGROUND)))
{
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
int i;
png_color back, back_1;
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];
for (i = 0; i < num_palette; i++)
{
if (i < (int)png_ptr->num_trans &&
png_ptr->trans[i] == 0)
{
palette[i] = back;
}
else if (i < (int)png_ptr->num_trans &&
png_ptr->trans[i] != 0xff)
{
int v;
v = png_ptr->gamma_to_1[png_ptr->palette[i].red];
v = (int)(((png_uint_32)(v) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back_1.red) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
palette[i].red = png_ptr->gamma_from_1[v];
v = png_ptr->gamma_to_1[png_ptr->palette[i].green];
v = (int)(((png_uint_32)(v) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back_1.green) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
palette[i].green = png_ptr->gamma_from_1[v];
v = png_ptr->gamma_to_1[png_ptr->palette[i].blue];
v = (int)(((png_uint_32)(v) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back_1.blue) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
palette[i].blue = png_ptr->gamma_from_1[v];
}
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;
png_color back;
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];
for (i = 0; i < num_palette; i++)
{
if (palette[i].red == 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)
{
int i;
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 < num_palette; i++)
{
if (i >= (int)png_ptr->num_trans ||
png_ptr->trans[i] == 0)
{
palette[i].red = back.red;
palette[i].green = back.green;
palette[i].blue = back.blue;
}
else if (i < (int)png_ptr->num_trans ||
png_ptr->trans[i] != 0xff)
{
palette[i].red = (png_byte)((
(png_uint_32)(png_ptr->palette[i].red) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back.red) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
palette[i].green = (png_byte)((
(png_uint_32)(png_ptr->palette[i].green) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back.green) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
palette[i].blue = (png_byte)((
(png_uint_32)(png_ptr->palette[i].blue) *
(png_uint_32)(png_ptr->trans[i]) +
(png_uint_32)(back.blue) *
(png_uint_32)(255 - png_ptr->trans[i]) +
127) / 255);
}
}
}
else /* assume grayscale palette (what else could it be?) */
{
int i;
for (i = 0; i < num_palette; i++)
{
if (i == (int)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 the color. note that paletted files are taken care of
elsewhere */
void
png_do_background(png_row_infop row_info, png_bytep row,
png_color_16p trans_values, png_color_16p background,
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)
{
png_bytep sp, dp;
png_uint_32 i;
int shift;
if (row && row_info && background &&
(!(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_info->width; i++)
{
if (((*sp >> shift) & 0x1) ==
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:
{
sp = row;
shift = 6;
for (i = 0; i < row_info->width; i++)
{
if (((*sp >> shift) & 0x3) ==
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:
{
sp = row;
shift = 4;
for (i = 0; i < row_info->width; i++)
{
if (((*sp >> shift) & 0xf) ==
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)
{
for (i = 0, sp = row;
i < row_info->width; i++, sp++)
{
if (*sp == trans_values->gray)
{
*sp = background->gray;
}
else
{
*sp = gamma_table[*sp];
}
}
}
else
#endif
{
for (i = 0, sp = row;
i < row_info->width; i++, sp++)
{
if (*sp == trans_values->gray)
{
*sp = background->gray;
}
}
}
break;
}
case 16:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_16)
{
for (i = 0, sp = row;
i < row_info->width; i++, sp += 2)
{
png_uint_16 v;
v = (png_uint_16)(((png_uint_16)(*sp) << 8) +
(png_uint_16)(*(sp + 1)));
if (v == trans_values->gray)
{
*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
{
for (i = 0, sp = row;
i < row_info->width; i++, sp += 2)
{
png_uint_16 v;
v = (png_uint_16)(((png_uint_16)(*sp) << 8) +
(png_uint_16)(*(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)
{
for (i = 0, sp = row;
i < row_info->width; i++, sp += 3)
{
if (*sp == trans_values->red &&
*(sp + 1) == trans_values->green &&
*(sp + 2) == trans_values->blue)
{
*sp = background->red;
*(sp + 1) = background->green;
*(sp + 2) = background->blue;
}
else
{
*sp = gamma_table[*sp];
*(sp + 1) = gamma_table[*(sp + 1)];
*(sp + 2) = gamma_table[*(sp + 2)];
}
}
}
else
#endif
{
for (i = 0, sp = row;
i < row_info->width; i++, sp += 3)
{
if (*sp == trans_values->red &&
*(sp + 1) == trans_values->green &&
*(sp + 2) == trans_values->blue)
{
*sp = background->red;
*(sp + 1) = background->green;
*(sp + 2) = background->blue;
}
}
}
}
else if (row_info->bit_depth == 16)
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_16)
{
for (i = 0, sp = row;
i < row_info->width; i++, sp += 6)
{
png_uint_16 r, g, b;
r = (png_uint_16)(((png_uint_16)(*sp) << 8) +
(png_uint_16)(*(sp + 1)));
g = (png_uint_16)(((png_uint_16)(*(sp + 2)) << 8) +
(png_uint_16)(*(sp + 3)));
b = (png_uint_16)(((png_uint_16)(*(sp + 4)) << 8) +
(png_uint_16)(*(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);
}
else
{
png_uint_16 v;
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
{
for (i = 0, sp = row;
i < row_info->width; i++, sp += 6)
{
png_uint_16 r, g, b;
r = (png_uint_16)(((png_uint_16)(*sp) << 8) +
(png_uint_16)(*(sp + 1)));
g = (png_uint_16)(((png_uint_16)(*(sp + 2)) << 8) +
(png_uint_16)(*(sp + 3)));
b = (png_uint_16)(((png_uint_16)(*(sp + 4)) << 8) +
(png_uint_16)(*(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:
{
switch (row_info->bit_depth)
{
case 8:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_to_1 && gamma_from_1 && gamma_table)
{
for (i = 0, sp = row,
dp = row;
i < row_info->width; i++, sp += 2, dp++)
{
png_uint_16 a;
a = *(sp + 1);
if (a == 0xff)
{
*dp = gamma_table[*sp];
}
else if (a == 0)
{
*dp = background->gray;
}
else
{
png_uint_16 v;
v = gamma_to_1[*sp];
v = (png_uint_16)(((png_uint_16)(v) * a +
(png_uint_16)background_1->gray *
(255 - a) + 127) / 255);
*dp = gamma_from_1[v];
}
}
}
else
#endif
{
for (i = 0, sp = row,
dp = row;
i < row_info->width; i++, sp += 2, dp++)
{
png_uint_16 a;
a = *(sp + 1);
if (a == 0xff)
{
*dp = *sp;
}
else if (a == 0)
{
*dp = background->gray;
}
else
{
*dp = (png_byte)(((png_uint_16)(*sp) * a +
(png_uint_16)background_1->gray *
(255 - a) + 127) / 255);
}
}
}
break;
}
case 16:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_16 && gamma_16_from_1 && gamma_16_to_1)
{
for (i = 0, sp = row,
dp = row;
i < row_info->width; i++, sp += 4, dp += 2)
{
png_uint_16 a;
a = (png_uint_16)(((png_uint_16)(*(sp + 2)) << 8) +
(png_uint_16)(*(sp + 3)));
if (a == (png_uint_16)0xffff)
{
png_uint_32 v;
v = gamma_16[
*(sp + 1) >> gamma_shift][*sp];
*dp = (png_byte)((v >> 8) & 0xff);
*(dp + 1) = (png_byte)(v & 0xff);
}
else if (a == 0)
{
*dp = (png_byte)((background->gray >> 8) & 0xff);
*(dp + 1) = (png_byte)(background->gray & 0xff);
}
else
{
png_uint_32 g, v;
g = gamma_16_to_1[
*(sp + 1) >> gamma_shift][*sp];
v = (g * (png_uint_32)a +
(png_uint_32)background_1->gray *
(png_uint_32)((png_uint_16)65535L - a) +
(png_uint_16)32767) / (png_uint_16)65535L;
v = gamma_16_from_1[(size_t)(
(v & 0xff) >> gamma_shift)][(size_t)(v >> 8)];
*dp = (png_byte)((v >> 8) & 0xff);
*(dp + 1) = (png_byte)(v & 0xff);
}
}
}
else
#endif
{
for (i = 0, sp = row,
dp = row;
i < row_info->width; i++, sp += 4, dp += 2)
{
png_uint_16 a;
a = (png_uint_16)(((png_uint_16)(*(sp + 2)) << 8) +
(png_uint_16)(*(sp + 3)));
if (a == (png_uint_16)0xffff)
{
png_memcpy(dp, sp, 2);
}
else if (a == 0)
{
*dp = (png_byte)((background->gray >> 8) & 0xff);
*(dp + 1) = (png_byte)(background->gray & 0xff);
}
else
{
png_uint_32 g, v;
g = ((png_uint_32)(*sp) << 8) +
(png_uint_32)(*(sp + 1));
v = (g * (png_uint_32)a +
(png_uint_32)background_1->gray *
(png_uint_32)((png_uint_16)65535L - a) +
(png_uint_16)32767) / (png_uint_16)65535L;
*dp = (png_byte)((v >> 8) & 0xff);
*(dp + 1) = (png_byte)(v & 0xff);
}
}
}
break;
}
}
break;
}
case PNG_COLOR_TYPE_RGB_ALPHA:
{
if (row_info->bit_depth == 8)
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_to_1 && gamma_from_1 && gamma_table)
{
for (i = 0, sp = row,
dp = row;
i < row_info->width; i++, sp += 4, dp += 3)
{
png_uint_16 a;
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)
{
*dp = background->red;
*(dp + 1) = background->green;
*(dp + 2) = background->blue;
}
else
{
png_uint_16 v;
v = gamma_to_1[*sp];
v = (png_uint_16)(((png_uint_16)(v) * a +
(png_uint_16)background_1->red *
(255 - a) + 127) / 255);
*dp = gamma_from_1[v];
v = gamma_to_1[*(sp + 1)];
v = (png_uint_16)(((png_uint_16)(v) * a +
(png_uint_16)background_1->green *
(255 - a) + 127) / 255);
*(dp + 1) = gamma_from_1[v];
v = gamma_to_1[*(sp + 2)];
v = (png_uint_16)(((png_uint_16)(v) * a +
(png_uint_16)background_1->blue *
(255 - a) + 127) / 255);
*(dp + 2) = gamma_from_1[v];
}
}
}
else
#endif
{
for (i = 0, sp = row,
dp = row;
i < row_info->width; i++, sp += 4, dp += 3)
{
png_uint_16 a;
a = *(sp + 3);
if (a == 0xff)
{
*dp = *sp;
*(dp + 1) = *(sp + 1);
*(dp + 2) = *(sp + 2);
}
else if (a == 0)
{
*dp = background->red;
*(dp + 1) = background->green;
*(dp + 2) = background->blue;
}
else
{
*dp = (png_byte)(((png_uint_16)(*sp) * a +
(png_uint_16)background->red *
(255 - a) + 127) / 255);
*(dp + 1) = (png_byte)(((png_uint_16)(*(sp + 1)) * a +
(png_uint_16)background->green *
(255 - a) + 127) / 255);
*(dp + 2) = (png_byte)(((png_uint_16)(*(sp + 2)) * a +
(png_uint_16)background->blue *
(255 - a) + 127) / 255);
}
}
}
}
else if (row_info->bit_depth == 16)
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (gamma_16 && gamma_16_from_1 && gamma_16_to_1)
{
for (i = 0, sp = row,
dp = row;
i < row_info->width; i++, sp += 8, dp += 6)
{
png_uint_16 a;
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)
{
*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_32 v;
v = gamma_16_to_1[
*(sp + 1) >> gamma_shift][*sp];
v = (v * (png_uint_32)a +
(png_uint_32)background->red *
(png_uint_32)((png_uint_16)65535L - a) +
(png_uint_16)32767) / (png_uint_16)65535L;
v = gamma_16_from_1[(size_t)(
(v & 0xff) >> gamma_shift)][(size_t)(v >> 8)];
*dp = (png_byte)((v >> 8) & 0xff);
*(dp + 1) = (png_byte)(v & 0xff);
v = gamma_16_to_1[
*(sp + 3) >> gamma_shift][*(sp + 2)];
v = (v * (png_uint_32)a +
(png_uint_32)background->green *
(png_uint_32)((png_uint_16)65535L - a) +
(png_uint_16)32767) / (png_uint_16)65535L;
v = gamma_16_from_1[(size_t)(
(v & 0xff) >> gamma_shift)][(size_t)(v >> 8)];
*(dp + 2) = (png_byte)((v >> 8) & 0xff);
*(dp + 3) = (png_byte)(v & 0xff);
v = gamma_16_to_1[
*(sp + 5) >> gamma_shift][*(sp + 4)];
v = (v * (png_uint_32)a +
(png_uint_32)background->blue *
(png_uint_32)((png_uint_16)65535L - a) +
(png_uint_16)32767) / (png_uint_16)65535L;
v = gamma_16_from_1[(size_t)(
(v & 0xff) >> gamma_shift)][(size_t)(v >> 8)];
*(dp + 4) = (png_byte)((v >> 8) & 0xff);
*(dp + 5) = (png_byte)(v & 0xff);
}
}
}
else
#endif
{
for (i = 0, sp = row,
dp = row;
i < row_info->width; i++, sp += 8, dp += 6)
{
png_uint_16 a;
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_32 r, g, b, v;
r = ((png_uint_32)(*sp) << 8) +
(png_uint_32)(*(sp + 1));
g = ((png_uint_32)(*(sp + 2)) << 8) +
(png_uint_32)(*(sp + 3));
b = ((png_uint_32)(*(sp + 4)) << 8) +
(png_uint_32)(*(sp + 5));
v = (r * (png_uint_32)a +
(png_uint_32)background->red *
(png_uint_32)((png_uint_32)65535L - a) +
(png_uint_32)32767) / (png_uint_32)65535L;
*dp = (png_byte)((v >> 8) & 0xff);
*(dp + 1) = (png_byte)(v & 0xff);
v = (g * (png_uint_32)a +
(png_uint_32)background->green *
(png_uint_32)((png_uint_32)65535L - a) +
(png_uint_32)32767) / (png_uint_32)65535L;
*(dp + 2) = (png_byte)((v >> 8) & 0xff);
*(dp + 3) = (png_byte)(v & 0xff);
v = (b * (png_uint_32)a +
(png_uint_32)background->blue *
(png_uint_32)((png_uint_32)65535L - a) +
(png_uint_32)32767) / (png_uint_32)65535L;
*(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 = ((row_info->width *
row_info->pixel_depth + 7) >> 3);
}
}
}
#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 trasparency 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(). If your bit depth <= 8, gamma correct a
palette, not the data. */
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)
{
png_bytep sp;
png_uint_32 i;
if (row && row_info && ((row_info->bit_depth <= 8 && gamma_table) ||
(row_info->bit_depth == 16 && gamma_16_table)))
{
switch (row_info->color_type)
{
case PNG_COLOR_TYPE_RGB:
{
if (row_info->bit_depth == 8)
{
for (i = 0, sp = row;
i < row_info->width; i++)
{
*sp = gamma_table[*sp];
sp++;
*sp = gamma_table[*sp];
sp++;
*sp = gamma_table[*sp];
sp++;
}
}
else if (row_info->bit_depth == 16)
{
for (i = 0, sp = row;
i < row_info->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)
{
for (i = 0, sp = row;
i < row_info->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)
{
for (i = 0, sp = row;
i < row_info->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 += 4;
}
}
break;
}
case PNG_COLOR_TYPE_GRAY_ALPHA:
{
if (row_info->bit_depth == 8)
{
for (i = 0, sp = row;
i < row_info->width; i++)
{
*sp = gamma_table[*sp];
sp++;
sp++;
}
}
else if (row_info->bit_depth == 16)
{
for (i = 0, sp = row;
i < row_info->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 += 4;
}
}
break;
}
case PNG_COLOR_TYPE_GRAY:
{
if (row_info->bit_depth == 8)
{
for (i = 0, sp = row;
i < row_info->width; i++)
{
*sp = gamma_table[*sp];
sp++;
}
}
else if (row_info->bit_depth == 16)
{
for (i = 0, sp = row;
i < row_info->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;
}
}
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
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;
if (row && row_info && 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_info->width - 1) >> 3);
dp = row + (png_size_t)row_info->width - 1;
shift = 7 - (int)((row_info->width + 7) & 7);
for (i = 0; i < row_info->width; i++)
{
if ((*sp >> shift) & 0x1)
*dp = 1;
else
*dp = 0;
if (shift == 7)
{
shift = 0;
sp--;
}
else
shift++;
dp--;
}
break;
}
case 2:
{
sp = row + (png_size_t)((row_info->width - 1) >> 2);
dp = row + (png_size_t)row_info->width - 1;
shift = (int)((3 - ((row_info->width + 3) & 3)) << 1);
for (i = 0; i < row_info->width; i++)
{
value = (*sp >> shift) & 0x3;
*dp = (png_byte)value;
if (shift == 6)
{
shift = 0;
sp--;
}
else
shift += 2;
dp--;
}
break;
}
case 4:
{
sp = row + (png_size_t)((row_info->width - 1) >> 1);
dp = row + (png_size_t)row_info->width - 1;
shift = (int)((row_info->width & 1) << 2);
for (i = 0; i < row_info->width; i++)
{
value = (*sp >> shift) & 0xf;
*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_info->width;
}
switch (row_info->bit_depth)
{
case 8:
{
if (trans)
{
sp = row + (png_size_t)row_info->width - 1;
dp = row + (png_size_t)(row_info->width << 2) - 1;
for (i = 0; i < row_info->width; i++)
{
if (*sp >= (png_byte)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_info->width * 4;
row_info->color_type = 6;
row_info->channels = 4;
}
else
{
sp = row + (png_size_t)row_info->width - 1;
dp = row + (png_size_t)(row_info->width * 3) - 1;
for (i = 0; i < row_info->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_info->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
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;
if (row && row_info)
{
if (row_info->color_type == PNG_COLOR_TYPE_GRAY &&
row_info->bit_depth < 8)
{
switch (row_info->bit_depth)
{
case 1:
{
sp = row + (png_size_t)((row_info->width - 1) >> 3);
dp = row + (png_size_t)row_info->width - 1;
shift = 7 - (int)((row_info->width + 7) & 7);
for (i = 0; i < row_info->width; i++)
{
if ((*sp >> shift) & 0x1)
*dp = 0xff;
else
*dp = 0;
if (shift == 7)
{
shift = 0;
sp--;
}
else
shift++;
dp--;
}
break;
}
case 2:
{
sp = row + (png_size_t)((row_info->width - 1) >> 2);
dp = row + (png_size_t)row_info->width - 1;
shift = (int)((3 - ((row_info->width + 3) & 3)) << 1);
for (i = 0; i < row_info->width; i++)
{
value = (*sp >> shift) & 0x3;
*dp = (png_byte)(value | (value << 2) | (value << 4) |
(value << 6));
if (shift == 6)
{
shift = 0;
sp--;
}
else
shift += 2;
dp--;
}
break;
}
case 4:
{
sp = row + (png_size_t)((row_info->width - 1) >> 1);
dp = row + (png_size_t)row_info->width - 1;
shift = (int)((1 - ((row_info->width + 1) & 1)) << 2);
for (i = 0; i < row_info->width; i++)
{
value = (*sp >> shift) & 0xf;
*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_info->width;
}
if (row_info->color_type == PNG_COLOR_TYPE_GRAY && trans_value)
{
if (row_info->bit_depth == 8)
{
sp = row + (png_size_t)row_info->width - 1;
dp = row + (png_size_t)(row_info->width << 1) - 1;
for (i = 0; i < row_info->width; i++)
{
if (*sp == trans_value->gray)
*dp-- = 0;
else
*dp-- = 0xff;
*dp-- = *sp--;
}
}
else if (row_info->bit_depth == 16)
{
sp = row + (png_size_t)row_info->rowbytes - 1;
dp = row + (png_size_t)(row_info->rowbytes << 1) - 1;
for (i = 0; i < row_info->width; i++)
{
if (((png_uint_16)*(sp) |
((png_uint_16)*(sp - 1) << 8)) == trans_value->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 =
((row_info->width * row_info->pixel_depth) >> 3);
}
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_info->width << 2) - 1;
for (i = 0; i < row_info->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 + (png_size_t)row_info->rowbytes - 1;
dp = row + (png_size_t)(row_info->width << 3) - 1;
for (i = 0; i < row_info->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 =
((row_info->width * row_info->pixel_depth) >> 3);
}
}
}
#endif
#if defined(PNG_READ_DITHER_SUPPORTED)
void
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;
if (row && row_info)
{
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_info->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 =
((row_info->width * row_info->pixel_depth + 7) >> 3);
}
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
palette_lookup && row_info->bit_depth == 8)
{
int r, g, b, p;
sp = row;
dp = row;
for (i = 0; i < row_info->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 =
((row_info->width * row_info->pixel_depth + 7) >> 3);
}
else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
dither_lookup && row_info->bit_depth == 8)
{
sp = row;
for (i = 0; i < row_info->width; i++, sp++)
{
*sp = dither_lookup[*sp];
}
}
}
}
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED)
static int png_gamma_shift[] =
{0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0};
void
png_build_gamma_table(png_structp png_ptr)
{
if (png_ptr->bit_depth <= 8)
{
int i;
double g;
g = 1.0 / (png_ptr->gamma * png_ptr->display_gamma);
png_ptr->gamma_table = (png_bytep)png_large_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 (png_ptr->transformations & PNG_BACKGROUND)
{
g = 1.0 / (png_ptr->gamma);
png_ptr->gamma_to_1 = (png_bytep)png_large_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);
}
g = 1.0 / (png_ptr->display_gamma);
png_ptr->gamma_from_1 = (png_bytep)png_large_malloc(png_ptr,
(png_uint_32)256);
for (i = 0; i < 256; i++)
{
png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0,
g) * 255.0 + .5);
}
}
}
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));
g = 1.0 / (png_ptr->gamma * png_ptr->display_gamma);
png_ptr->gamma_16_table = (png_uint_16pp)png_large_malloc(png_ptr,
num * sizeof (png_uint_16p ));
if ((png_ptr->transformations & PNG_16_TO_8) &&
!(png_ptr->transformations & 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_large_malloc(png_ptr,
256 * 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_large_malloc(png_ptr,
256 * 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 (png_ptr->transformations & PNG_BACKGROUND)
{
g = 1.0 / (png_ptr->gamma);
png_ptr->gamma_16_to_1 = (png_uint_16pp)png_large_malloc(png_ptr,
num * sizeof (png_uint_16p ));
for (i = 0; i < num; i++)
{
png_ptr->gamma_16_to_1[i] = (png_uint_16p)png_large_malloc(png_ptr,
256 * 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);
}
}
g = 1.0 / (png_ptr->display_gamma);
png_ptr->gamma_16_from_1 = (png_uint_16pp)png_large_malloc(png_ptr,
num * sizeof (png_uint_16p));
for (i = 0; i < num; i++)
{
png_ptr->gamma_16_from_1[i] = (png_uint_16p)png_large_malloc(png_ptr,
256 * 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
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.