blob: 821fdc546daa27efbbe1f36289607640e47175a6 [file] [log] [blame]
/* pngrtran.c - transforms the data in a row for PNG readers
*
* Last changed in libpng 1.2.53 [February 26, 2015]
* Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*
* This file contains functions optionally called by an application
* in order to tell libpng how to handle data when reading a PNG.
* Transformations that are used in both reading and writing are
* in pngtrans.c.
*/
#define PNG_INTERNAL
#define PNG_NO_PEDANTIC_WARNINGS
#include "png.h"
#ifdef PNG_READ_SUPPORTED
/* Set the action on getting a CRC error for an ancillary or critical chunk. */
void PNGAPI
png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
{
png_debug(1, "in png_set_crc_action");
if (png_ptr == NULL)
return;
/* Tell libpng how we react to CRC errors in critical chunks */
switch (crit_action)
{
case PNG_CRC_NO_CHANGE: /* Leave setting as is */
break;
case PNG_CRC_WARN_USE: /* Warn/use data */
png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
break;
case PNG_CRC_QUIET_USE: /* Quiet/use data */
png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
PNG_FLAG_CRC_CRITICAL_IGNORE;
break;
case PNG_CRC_WARN_DISCARD: /* Not a valid action for critical data */
png_warning(png_ptr,
"Can't discard critical data on CRC error.");
case PNG_CRC_ERROR_QUIT: /* Error/quit */
case PNG_CRC_DEFAULT:
default:
png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
break;
}
/* Tell libpng how we react to CRC errors in ancillary chunks */
switch (ancil_action)
{
case PNG_CRC_NO_CHANGE: /* Leave setting as is */
break;
case PNG_CRC_WARN_USE: /* Warn/use data */
png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
break;
case PNG_CRC_QUIET_USE: /* Quiet/use data */
png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
PNG_FLAG_CRC_ANCILLARY_NOWARN;
break;
case PNG_CRC_ERROR_QUIT: /* Error/quit */
png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
break;
case PNG_CRC_WARN_DISCARD: /* Warn/discard data */
case PNG_CRC_DEFAULT:
default:
png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
break;
}
}
#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
defined(PNG_FLOATING_POINT_SUPPORTED)
/* Handle alpha and tRNS via a background color */
void PNGAPI
png_set_background(png_structp png_ptr,
png_color_16p background_color, int background_gamma_code,
int need_expand, double background_gamma)
{
png_debug(1, "in png_set_background");
if (png_ptr == NULL)
return;
if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
{
png_warning(png_ptr, "Application must supply a known background gamma");
return;
}
png_ptr->transformations |= PNG_BACKGROUND;
png_memcpy(&(png_ptr->background), background_color,
png_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
#ifdef PNG_READ_16_TO_8_SUPPORTED
/* Strip 16 bit depth files to 8 bit depth */
void PNGAPI
png_set_strip_16(png_structp png_ptr)
{
png_debug(1, "in png_set_strip_16");
if (png_ptr == NULL)
return;
png_ptr->transformations |= PNG_16_TO_8;
}
#endif
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
void PNGAPI
png_set_strip_alpha(png_structp png_ptr)
{
png_debug(1, "in png_set_strip_alpha");
if (png_ptr == NULL)
return;
png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;
}
#endif
#ifdef 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
* of colors is greater then the maximum number, the palette will be
* modified to fit in the maximum number. "full_dither" indicates
* whether we need a dithering cube set up for RGB images, or if we
* simply are reducing the number of colors in a paletted image.
*/
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 PNGAPI
png_set_dither(png_structp png_ptr, png_colorp palette,
int num_palette, int maximum_colors, png_uint_16p histogram,
int full_dither)
{
png_debug(1, "in png_set_dither");
if (png_ptr == NULL)
return;
png_ptr->transformations |= PNG_DITHER;
if (!full_dither)
{
int i;
png_ptr->dither_index = (png_bytep)png_malloc(png_ptr,
(png_uint_32)(num_palette * png_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 != NULL)
{
/* This is easy enough, just throw out the least used colors.
* Perhaps not the best solution, but good enough.
*/
int i;
/* Initialize an array to sort colors */
png_ptr->dither_sort = (png_bytep)png_malloc(png_ptr,
(png_uint_32)(num_palette * png_sizeof(png_byte)));
/* Initialize the dither_sort array */
for (i = 0; i < num_palette; i++)
png_ptr->dither_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[png_ptr->dither_sort[j]]
< histogram[png_ptr->dither_sort[j + 1]])
{
png_byte t;
t = png_ptr->dither_sort[j];
png_ptr->dither_sort[j] = png_ptr->dither_sort[j + 1];
png_ptr->dither_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 = num_palette;
/* Put all the useful colors within the max, but don't
* move the others.
*/
for (i = 0; i < maximum_colors; i++)
{
if ((int)png_ptr->dither_sort[i] >= maximum_colors)
{
do
j--;
while ((int)png_ptr->dither_sort[j] >= maximum_colors);
palette[i] = palette[j];
}
}
}
else
{
int j = num_palette;
/* Move all the used colors inside the max limit, and
* develop a translation table.
*/
for (i = 0; i < maximum_colors; i++)
{
/* Only move the colors we need to */
if ((int)png_ptr->dither_sort[i] >= maximum_colors)
{
png_color tmp_color;
do
j--;
while ((int)png_ptr->dither_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 ((int)png_ptr->dither_index[i] >= maximum_colors)
{
int min_d, k, min_k, d_index;
/* Find the closest color to one we threw out */
d_index = png_ptr->dither_index[i];
min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
for (k = 1, min_k = 0; k < maximum_colors; k++)
{
int d;
d = PNG_COLOR_DIST(palette[d_index], palette[k]);
if (d < min_d)
{
min_d = d;
min_k = k;
}
}
/* Point to closest color */
png_ptr->dither_index[i] = (png_byte)min_k;
}
}
}
png_free(png_ptr, png_ptr->dither_sort);
png_ptr->dither_sort = NULL;
}
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).
* [We don't understand this at all, so if someone wants to
* work on improving it, be our guest - AED, GRP]
*/
int i;
int max_d;
int num_new_palette;
png_dsortp t;
png_dsortpp hash;
t = NULL;
/* Initialize palette index arrays */
png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
(png_uint_32)(num_palette * png_sizeof(png_byte)));
png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
(png_uint_32)(num_palette * png_sizeof(png_byte)));
/* Initialize the sort array */
for (i = 0; i < num_palette; i++)
{
png_ptr->index_to_palette[i] = (png_byte)i;
png_ptr->palette_to_index[i] = (png_byte)i;
}
hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 *
png_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)
{
t = (png_dsortp)png_malloc_warn(png_ptr,
(png_uint_32)(png_sizeof(png_dsort)));
if (t == NULL)
break;
t->next = hash[d];
t->left = (png_byte)i;
t->right = (png_byte)j;
hash[d] = t;
}
}
if (t == NULL)
break;
}
if (t != NULL)
for (i = 0; i <= max_d; i++)
{
if (hash[i] != NULL)
{
png_dsortp p;
for (p = hash[i]; p; p = p->next)
{
if ((int)png_ptr->index_to_palette[p->left]
< num_new_palette &&
(int)png_ptr->index_to_palette[p->right]
< num_new_palette)
{
int j, next_j;
if (num_new_palette & 0x01)
{
j = p->left;
next_j = p->right;
}
else
{
j = p->right;
next_j = p->left;
}
num_new_palette--;
palette[png_ptr->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] ==
png_ptr->index_to_palette[j])
png_ptr->dither_index[k] =
png_ptr->index_to_palette[next_j];
if ((int)png_ptr->dither_index[k] ==
num_new_palette)
png_ptr->dither_index[k] =
png_ptr->index_to_palette[j];
}
}
png_ptr->index_to_palette[png_ptr->palette_to_index
[num_new_palette]] = png_ptr->index_to_palette[j];
png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
= png_ptr->palette_to_index[num_new_palette];
png_ptr->index_to_palette[j] =
(png_byte)num_new_palette;
png_ptr->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] != NULL)
{
png_dsortp p = hash[i];
while (p)
{
t = p->next;
png_free(png_ptr, p);
p = t;
}
}
hash[i] = 0;
}
max_d += 96;
}
png_free(png_ptr, hash);
png_free(png_ptr, png_ptr->palette_to_index);
png_free(png_ptr, png_ptr->index_to_palette);
png_ptr->palette_to_index = NULL;
png_ptr->index_to_palette = NULL;
}
num_palette = maximum_colors;
}
if (png_ptr->palette == NULL)
{
png_ptr->palette = palette;
}
png_ptr->num_palette = (png_uint_16)num_palette;
if (full_dither)
{
int i;
png_bytep distance;
int total_bits = PNG_DITHER_RED_BITS + PNG_DITHER_GREEN_BITS +
PNG_DITHER_BLUE_BITS;
int num_red = (1 << PNG_DITHER_RED_BITS);
int num_green = (1 << PNG_DITHER_GREEN_BITS);
int num_blue = (1 << PNG_DITHER_BLUE_BITS);
png_size_t num_entries = ((png_size_t)1 << total_bits);
png_ptr->palette_lookup = (png_bytep )png_calloc(png_ptr,
(png_uint_32)(num_entries * png_sizeof(png_byte)));
distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *
png_sizeof(png_byte)));
png_memset(distance, 0xff, num_entries * png_sizeof(png_byte));
for (i = 0; i < num_palette; i++)
{
int ir, ig, ib;
int r = (palette[i].red >> (8 - PNG_DITHER_RED_BITS));
int g = (palette[i].green >> (8 - PNG_DITHER_GREEN_BITS));
int b = (palette[i].blue >> (8 - PNG_DITHER_BLUE_BITS));
for (ir = 0; ir < num_red; ir++)
{
/* int dr = abs(ir - r); */
int dr = ((ir > r) ? ir - r : r - ir);
int index_r = (ir << (PNG_DITHER_BLUE_BITS +
PNG_DITHER_GREEN_BITS));
for (ig = 0; ig < num_green; ig++)
{
/* int dg = abs(ig - g); */
int dg = ((ig > g) ? ig - g : g - ig);
int dt = dr + dg;
int dm = ((dr > dg) ? dr : dg);
int index_g = index_r | (ig << PNG_DITHER_BLUE_BITS);
for (ib = 0; ib < num_blue; ib++)
{
int d_index = index_g | ib;
/* int db = abs(ib - b); */
int db = ((ib > b) ? ib - b : b - ib);
int dmax = ((dm > db) ? dm : db);
int d = dmax + dt + db;
if (d < (int)distance[d_index])
{
distance[d_index] = (png_byte)d;
png_ptr->palette_lookup[d_index] = (png_byte)i;
}
}
}
}
}
png_free(png_ptr, distance);
}
}
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
/* Transform the image from the file_gamma to the screen_gamma. We
* only do transformations on images where the file_gamma and screen_gamma
* are not close reciprocals, otherwise it slows things down slightly, and
* also needlessly introduces small errors.
*
* We will turn off gamma transformation later if no semitransparent entries
* are present in the tRNS array for palette images. We can't do it here
* because we don't necessarily have the tRNS chunk yet.
*/
void PNGAPI
png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
{
png_debug(1, "in png_set_gamma");
if (png_ptr == NULL)
return;
if ((fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD) ||
(png_ptr->color_type & PNG_COLOR_MASK_ALPHA) ||
(png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
png_ptr->transformations |= PNG_GAMMA;
png_ptr->gamma = (float)file_gamma;
png_ptr->screen_gamma = (float)scrn_gamma;
}
#endif
#ifdef PNG_READ_EXPAND_SUPPORTED
/* Expand paletted images to RGB, expand grayscale images of
* less than 8-bit depth to 8-bit depth, and expand tRNS chunks
* to alpha channels.
*/
void PNGAPI
png_set_expand(png_structp png_ptr)
{
png_debug(1, "in png_set_expand");
if (png_ptr == NULL)
return;
png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
}
/* GRR 19990627: the following three functions currently are identical
* to png_set_expand(). However, it is entirely reasonable that someone
* might wish to expand an indexed image to RGB but *not* expand a single,
* fully transparent palette entry to a full alpha channel--perhaps instead
* convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
* the transparent color with a particular RGB value, or drop tRNS entirely.
* IOW, a future version of the library may make the transformations flag
* a bit more fine-grained, with separate bits for each of these three
* functions.
*
* More to the point, these functions make it obvious what libpng will be
* doing, whereas "expand" can (and does) mean any number of things.
*
* GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
* to expand only the sample depth but not to expand the tRNS to alpha
* and its name was changed to png_set_expand_gray_1_2_4_to_8().
*/
/* Expand paletted images to RGB. */
void PNGAPI
png_set_palette_to_rgb(png_structp png_ptr)
{
png_debug(1, "in png_set_palette_to_rgb");
if (png_ptr == NULL)
return;
png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
}
#ifndef PNG_1_0_X
/* Expand grayscale images of less than 8-bit depth to 8 bits. */
void PNGAPI
png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)
{
png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
if (png_ptr == NULL)
return;
png_ptr->transformations |= PNG_EXPAND;
png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
}
#endif
#if defined(PNG_1_0_X) || defined(PNG_1_2_X)
/* Expand grayscale images of less than 8-bit depth to 8 bits. */
/* Deprecated as of libpng-1.2.9 */
void PNGAPI
png_set_gray_1_2_4_to_8(png_structp png_ptr)
{
png_debug(1, "in png_set_gray_1_2_4_to_8");
if (png_ptr == NULL)
return;
png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
}
#endif
/* Expand tRNS chunks to alpha channels. */
void PNGAPI
png_set_tRNS_to_alpha(png_structp png_ptr)
{
png_debug(1, "in png_set_tRNS_to_alpha");
png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
}
#endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
void PNGAPI
png_set_gray_to_rgb(png_structp png_ptr)
{
png_debug(1, "in png_set_gray_to_rgb");
png_ptr->transformations |= PNG_GRAY_TO_RGB;
png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
}
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
#ifdef PNG_FLOATING_POINT_SUPPORTED
/* Convert a RGB image to a grayscale of the same width. This allows us,
* for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
*/
void PNGAPI
png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red,
double green)
{
int red_fixed, green_fixed;
if (png_ptr == NULL)
return;
if (red > 21474.83647 || red < -21474.83648 ||
green > 21474.83647 || green < -21474.83648)
{
png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");
red_fixed = -1;
green_fixed = -1;
}
else
{
red_fixed = (int)((float)red*100000.0 + 0.5);
green_fixed = (int)((float)green*100000.0 + 0.5);
}
png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed);
}
#endif
void PNGAPI
png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action,
png_fixed_point red, png_fixed_point green)
{
png_debug(1, "in png_set_rgb_to_gray");
if (png_ptr == NULL)
return;
switch(error_action)
{
case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY;
break;
case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
break;
case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
}
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
#ifdef PNG_READ_EXPAND_SUPPORTED
png_ptr->transformations |= PNG_EXPAND;
#else
{
png_warning(png_ptr,
"Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED.");
png_ptr->transformations &= ~PNG_RGB_TO_GRAY;
}
#endif
{
png_uint_16 red_int, green_int;
if (red < 0 || green < 0)
{
red_int = 6968; /* .212671 * 32768 + .5 */
green_int = 23434; /* .715160 * 32768 + .5 */
}
else if (red + green < 100000L)
{
red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L);
green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L);
}
else
{
png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");
red_int = 6968;
green_int = 23434;
}
png_ptr->rgb_to_gray_red_coeff = red_int;
png_ptr->rgb_to_gray_green_coeff = green_int;
png_ptr->rgb_to_gray_blue_coeff =
(png_uint_16)(32768 - red_int - green_int);
}
}
#endif
#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
defined(PNG_LEGACY_SUPPORTED) || \
defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
void PNGAPI
png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
read_user_transform_fn)
{
png_debug(1, "in png_set_read_user_transform_fn");
if (png_ptr == NULL)
return;
#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
png_ptr->transformations |= PNG_USER_TRANSFORM;
png_ptr->read_user_transform_fn = read_user_transform_fn;
#endif
#ifdef PNG_LEGACY_SUPPORTED
if (read_user_transform_fn)
png_warning(png_ptr,
"This version of libpng does not support user transforms");
#endif
}
#endif
/* Initialize everything needed for the read. This includes modifying
* the palette.
*/
void /* PRIVATE */
png_init_read_transformations(png_structp png_ptr)
{
png_debug(1, "in png_init_read_transformations");
#ifdef PNG_USELESS_TESTS_SUPPORTED
if (png_ptr != NULL)
#endif
{
#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
defined(PNG_READ_SHIFT_SUPPORTED) || \
defined(PNG_READ_GAMMA_SUPPORTED)
int color_type = png_ptr->color_type;
#endif
#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
/* Detect gray background and attempt to enable optimization
* for gray --> RGB case
*
* Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
* RGB_ALPHA (in which case need_expand is superfluous anyway), the
* background color might actually be gray yet not be flagged as such.
* This is not a problem for the current code, which uses
* PNG_BACKGROUND_IS_GRAY only to decide when to do the
* png_do_gray_to_rgb() transformation.
*/
if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
!(color_type & PNG_COLOR_MASK_COLOR))
{
png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
} else if ((png_ptr->transformations & PNG_BACKGROUND) &&
!(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
(png_ptr->transformations & PNG_GRAY_TO_RGB) &&
png_ptr->background.red == png_ptr->background.green &&
png_ptr->background.red == png_ptr->background.blue)
{
png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
png_ptr->background.gray = png_ptr->background.red;
}
#endif
if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
(png_ptr->transformations & PNG_EXPAND))
{
if (!(color_type & PNG_COLOR_MASK_COLOR)) /* i.e., GRAY or GRAY_ALPHA */
{
/* Expand background and tRNS chunks */
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;
if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
{
png_ptr->trans_values.gray *= (png_uint_16)0xff;
png_ptr->trans_values.red = png_ptr->trans_values.green
= png_ptr->trans_values.blue = png_ptr->trans_values.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;
if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
{
png_ptr->trans_values.gray *= (png_uint_16)0x55;
png_ptr->trans_values.red = png_ptr->trans_values.green
= png_ptr->trans_values.blue = png_ptr->trans_values.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;
if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
{
png_ptr->trans_values.gray *= (png_uint_16)0x11;
png_ptr->trans_values.red = png_ptr->trans_values.green
= png_ptr->trans_values.blue = png_ptr->trans_values.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;
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_ALPHA)
{
#ifdef PNG_READ_EXPAND_SUPPORTED
if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
#endif
{
/* Invert the alpha channel (in tRNS) unless the pixels are
* going to be expanded, in which case leave it for later
*/
int i, istop;
istop=(int)png_ptr->num_trans;
for (i=0; i<istop; i++)
png_ptr->trans[i] = (png_byte)(255 - png_ptr->trans[i]);
}
}
#endif
}
}
#endif
#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
png_ptr->background_1 = png_ptr->background;
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
if ((color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_trans != 0)
&& (fabs(png_ptr->screen_gamma * png_ptr->gamma - 1.0)
< PNG_GAMMA_THRESHOLD))
{
int i, k;
k=0;
for (i=0; i<png_ptr->num_trans; i++)
{
if (png_ptr->trans[i] != 0 && png_ptr->trans[i] != 0xff)
{
k=1; /* Partial transparency is present */
break;
}
}
if (k == 0)
png_ptr->transformations &= ~PNG_GAMMA;
}
if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) &&
png_ptr->gamma != 0.0)
{
png_build_gamma_table(png_ptr);
#ifdef PNG_READ_BACKGROUND_SUPPORTED
if (png_ptr->transformations & PNG_BACKGROUND)
{
if (color_type == PNG_COLOR_TYPE_PALETTE)
{
/* Could skip if no transparency */
png_color back, back_1;
png_colorp palette = png_ptr->palette;
int num_palette = png_ptr->num_palette;
int i;
if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
{
back.red = png_ptr->gamma_table[png_ptr->background.red];
back.green = png_ptr->gamma_table[png_ptr->background.green];
back.blue = png_ptr->gamma_table[png_ptr->background.blue];
back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
}
else
{
double g, gs;
switch (png_ptr->background_gamma_type)
{
case PNG_BACKGROUND_GAMMA_SCREEN:
g = (png_ptr->screen_gamma);
gs = 1.0;
break;
case PNG_BACKGROUND_GAMMA_FILE:
g = 1.0 / (png_ptr->gamma);
gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
break;
case PNG_BACKGROUND_GAMMA_UNIQUE:
g = 1.0 / (png_ptr->background_gamma);
gs = 1.0 / (png_ptr->background_gamma *
png_ptr->screen_gamma);
break;
default:
g = 1.0; /* back_1 */
gs = 1.0; /* back */
}
if ( fabs(gs - 1.0) < PNG_GAMMA_THRESHOLD)
{
back.red = (png_byte)png_ptr->background.red;
back.green = (png_byte)png_ptr->background.green;
back.blue = (png_byte)png_ptr->background.blue;
}
else
{
back.red = (png_byte)(pow(
(double)png_ptr->background.red/255, gs) * 255.0 + .5);
back.green = (png_byte)(pow(
(double)png_ptr->background.green/255, gs) * 255.0
+ .5);
back.blue = (png_byte)(pow(
(double)png_ptr->background.blue/255, gs) * 255.0 + .5);
}
back_1.red = (png_byte)(pow(
(double)png_ptr->background.red/255, g) * 255.0 + .5);
back_1.green = (png_byte)(pow(
(double)png_ptr->background.green/255, g) * 255.0 + .5);
back_1.blue = (png_byte)(pow(
(double)png_ptr->background.blue/255, g) * 255.0 + .5);
}
for (i = 0; i < num_palette; i++)
{
if (i < (int)png_ptr->num_trans && png_ptr->trans[i] != 0xff)
{
if (png_ptr->trans[i] == 0)
{
palette[i] = back;
}
else /* if (png_ptr->trans[i] != 0xff) */
{
png_byte v, w;
v = png_ptr->gamma_to_1[palette[i].red];
png_composite(w, v, png_ptr->trans[i], back_1.red);
palette[i].red = png_ptr->gamma_from_1[w];
v = png_ptr->gamma_to_1[palette[i].green];
png_composite(w, v, png_ptr->trans[i], back_1.green);
palette[i].green = png_ptr->gamma_from_1[w];
v = png_ptr->gamma_to_1[palette[i].blue];
png_composite(w, v, png_ptr->trans[i], back_1.blue);
palette[i].blue = png_ptr->gamma_from_1[w];
}
}
else
{
palette[i].red = png_ptr->gamma_table[palette[i].red];
palette[i].green = png_ptr->gamma_table[palette[i].green];
palette[i].blue = png_ptr->gamma_table[palette[i].blue];
}
}
/* Prevent the transformations being done again, and make sure
* that the now spurious alpha channel is stripped - the code
* has just reduced background composition and gamma correction
* to a simple alpha channel strip.
*/
png_ptr->transformations &= ~PNG_BACKGROUND;
png_ptr->transformations &= ~PNG_GAMMA;
png_ptr->transformations |= PNG_STRIP_ALPHA;
}
/* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
else
/* color_type != PNG_COLOR_TYPE_PALETTE */
{
double m = (double)(((png_uint_32)1 << png_ptr->bit_depth) - 1);
double g = 1.0;
double gs = 1.0;
switch (png_ptr->background_gamma_type)
{
case PNG_BACKGROUND_GAMMA_SCREEN:
g = (png_ptr->screen_gamma);
gs = 1.0;
break;
case PNG_BACKGROUND_GAMMA_FILE:
g = 1.0 / (png_ptr->gamma);
gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
break;
case PNG_BACKGROUND_GAMMA_UNIQUE:
g = 1.0 / (png_ptr->background_gamma);
gs = 1.0 / (png_ptr->background_gamma *
png_ptr->screen_gamma);
break;
}
png_ptr->background_1.gray = (png_uint_16)(pow(
(double)png_ptr->background.gray / m, g) * m + .5);
png_ptr->background.gray = (png_uint_16)(pow(
(double)png_ptr->background.gray / m, gs) * m + .5);
if ((png_ptr->background.red != png_ptr->background.green) ||
(png_ptr->background.red != png_ptr->background.blue) ||
(png_ptr->background.red != png_ptr->background.gray))
{
/* RGB or RGBA with color background */
png_ptr->background_1.red = (png_uint_16)(pow(
(double)png_ptr->background.red / m, g) * m + .5);
png_ptr->background_1.green = (png_uint_16)(pow(
(double)png_ptr->background.green / m, g) * m + .5);
png_ptr->background_1.blue = (png_uint_16)(pow(
(double)png_ptr->background.blue / m, g) * m + .5);
png_ptr->background.red = (png_uint_16)(pow(
(double)png_ptr->background.red / m, gs) * m + .5);
png_ptr->background.green = (png_uint_16)(pow(
(double)png_ptr->background.green / m, gs) * m + .5);
png_ptr->background.blue = (png_uint_16)(pow(
(double)png_ptr->background.blue / m, gs) * m + .5);
}
else
{
/* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
png_ptr->background_1.red = png_ptr->background_1.green
= png_ptr->background_1.blue = png_ptr->background_1.gray;
png_ptr->background.red = png_ptr->background.green
= png_ptr->background.blue = png_ptr->background.gray;
}
}
}
else
/* Transformation does not include PNG_BACKGROUND */
#endif /* PNG_READ_BACKGROUND_SUPPORTED */
if (color_type == PNG_COLOR_TYPE_PALETTE)
{
png_colorp palette = png_ptr->palette;
int num_palette = png_ptr->num_palette;
int i;
for (i = 0; i < num_palette; i++)
{
palette[i].red = png_ptr->gamma_table[palette[i].red];
palette[i].green = png_ptr->gamma_table[palette[i].green];
palette[i].blue = png_ptr->gamma_table[palette[i].blue];
}
/* Done the gamma correction. */
png_ptr->transformations &= ~PNG_GAMMA;
}
}
#ifdef PNG_READ_BACKGROUND_SUPPORTED
else
#endif
#endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */
#ifdef PNG_READ_BACKGROUND_SUPPORTED
/* No GAMMA transformation */
if ((png_ptr->transformations & PNG_BACKGROUND) &&
(color_type == PNG_COLOR_TYPE_PALETTE))
{
int i;
int istop = (int)png_ptr->num_trans;
png_color back;
png_colorp palette = png_ptr->palette;
back.red = (png_byte)png_ptr->background.red;
back.green = (png_byte)png_ptr->background.green;
back.blue = (png_byte)png_ptr->background.blue;
for (i = 0; i < istop; i++)
{
if (png_ptr->trans[i] == 0)
{
palette[i] = back;
}
else if (png_ptr->trans[i] != 0xff)
{
/* The png_composite() macro is defined in png.h */
png_composite(palette[i].red, palette[i].red,
png_ptr->trans[i], back.red);
png_composite(palette[i].green, palette[i].green,
png_ptr->trans[i], back.green);
png_composite(palette[i].blue, palette[i].blue,
png_ptr->trans[i], back.blue);
}
}
/* Handled alpha, still need to strip the channel. */
png_ptr->transformations &= ~PNG_BACKGROUND;
png_ptr->transformations |= PNG_STRIP_ALPHA;
}
#endif /* PNG_READ_BACKGROUND_SUPPORTED */
#ifdef PNG_READ_SHIFT_SUPPORTED
if ((png_ptr->transformations & PNG_SHIFT) &&
!(png_ptr->transformations & PNG_EXPAND) &&
(color_type == PNG_COLOR_TYPE_PALETTE))
{
png_uint_16 i;
png_uint_16 istop = png_ptr->num_palette;
int sr = 8 - png_ptr->sig_bit.red;
int sg = 8 - png_ptr->sig_bit.green;
int sb = 8 - png_ptr->sig_bit.blue;
if (sr < 0 || sr > 8)
sr = 0;
if (sg < 0 || sg > 8)
sg = 0;
if (sb < 0 || sb > 8)
sb = 0;
for (i = 0; i < istop; i++)
{
png_ptr->palette[i].red >>= sr;
png_ptr->palette[i].green >>= sg;
png_ptr->palette[i].blue >>= sb;
}
png_ptr->transformations &= ~PNG_SHIFT;
}
#endif /* PNG_READ_SHIFT_SUPPORTED */
}
#if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
&& !defined(PNG_READ_BACKGROUND_SUPPORTED)
if (png_ptr)
return;
#endif
}
/* 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 /* PRIVATE */
png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
{
png_debug(1, "in png_read_transform_info");
#ifdef PNG_READ_EXPAND_SUPPORTED
if (png_ptr->transformations & PNG_EXPAND)
{
if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
if (png_ptr->num_trans)
info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
else
info_ptr->color_type = PNG_COLOR_TYPE_RGB;
info_ptr->bit_depth = 8;
info_ptr->num_trans = 0;
}
else
{
if (png_ptr->num_trans)
{
if (png_ptr->transformations & PNG_EXPAND_tRNS)
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
#ifdef 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
#ifdef PNG_READ_GAMMA_SUPPORTED
if (png_ptr->transformations & PNG_GAMMA)
{
#ifdef PNG_FLOATING_POINT_SUPPORTED
info_ptr->gamma = png_ptr->gamma;
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
info_ptr->int_gamma = png_ptr->int_gamma;
#endif
}
#endif
#ifdef 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
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
if (png_ptr->transformations & PNG_GRAY_TO_RGB)
info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
if (png_ptr->transformations & PNG_RGB_TO_GRAY)
info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR;
#endif
#ifdef 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
#ifdef PNG_READ_PACK_SUPPORTED
if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
info_ptr->bit_depth = 8;
#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;
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)
info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
#endif
if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
info_ptr->channels++;
#ifdef PNG_READ_FILLER_SUPPORTED
/* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */
if ((png_ptr->transformations & PNG_FILLER) &&
((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
(info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
{
info_ptr->channels++;
/* If adding a true alpha channel not just filler */
#ifndef PNG_1_0_X
if (png_ptr->transformations & PNG_ADD_ALPHA)
info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
#endif
}
#endif
#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
if (png_ptr->transformations & PNG_USER_TRANSFORM)
{
if (info_ptr->bit_depth < png_ptr->user_transform_depth)
info_ptr->bit_depth = png_ptr->user_transform_depth;
if (info_ptr->channels < png_ptr->user_transform_channels)
info_ptr->channels = png_ptr->user_transform_channels;
}
#endif
info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
info_ptr->bit_depth);
info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
#ifndef PNG_READ_EXPAND_SUPPORTED
if (png_ptr)
return;
#endif
}
/* 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 /* PRIVATE */
png_do_read_transformations(png_structp png_ptr)
{
png_debug(1, "in png_do_read_transformations");
if (png_ptr->row_buf == NULL)
{
#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
char msg[50];
png_snprintf2(msg, 50,
"NULL row buffer for row %ld, pass %d", (long)png_ptr->row_number,
png_ptr->pass);
png_error(png_ptr, msg);
#else
png_error(png_ptr, "NULL row buffer");
#endif
}
#ifdef PNG_WARN_UNINITIALIZED_ROW
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
/* Application has failed to call either png_read_start_image()
* or png_read_update_info() after setting transforms that expand
* pixels. This check added to libpng-1.2.19
*/
#if (PNG_WARN_UNINITIALIZED_ROW==1)
png_error(png_ptr, "Uninitialized row");
#else
png_warning(png_ptr, "Uninitialized row");
#endif
#endif
#ifdef PNG_READ_EXPAND_SUPPORTED
if (png_ptr->transformations & PNG_EXPAND)
{
if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE)
{
if (png_ptr->palette == NULL)
png_error (png_ptr, "Palette is NULL in indexed image");
png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1,
png_ptr->palette, png_ptr->trans, png_ptr->num_trans);
}
else
{
if (png_ptr->num_trans &&
(png_ptr->transformations & PNG_EXPAND_tRNS))
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
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)
png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
PNG_FLAG_FILLER_AFTER | (png_ptr->flags & PNG_FLAG_STRIP_ALPHA));
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
if (png_ptr->transformations & PNG_RGB_TO_GRAY)
{
int rgb_error =
png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info),
png_ptr->row_buf + 1);
if (rgb_error)
{
png_ptr->rgb_to_gray_status=1;
if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
PNG_RGB_TO_GRAY_WARN)
png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
PNG_RGB_TO_GRAY_ERR)
png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
}
}
#endif
/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
*
* In most cases, the "simple transparency" should be done prior to doing
* gray-to-RGB, or you will have to test 3x as many bytes to check if a
* pixel is transparent. You would also need to make sure that the
* transparency information is upgraded to RGB.
*
* To summarize, the current flow is:
* - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
* with background "in place" if transparent,
* convert to RGB if necessary
* - Gray + alpha -> composite with gray background and remove alpha bytes,
* convert to RGB if necessary
*
* To support RGB backgrounds for gray images we need:
* - Gray + simple transparency -> convert to RGB + simple transparency,
* compare 3 or 6 bytes and composite with
* background "in place" if transparent
* (3x compare/pixel compared to doing
* composite with gray bkgrnd)
* - Gray + alpha -> convert to RGB + alpha, composite with background and
* remove alpha bytes (3x float
* operations/pixel compared with composite
* on gray background)
*
* Greg's change will do this. The reason it wasn't done before is for
* performance, as this increases the per-pixel operations. If we would check
* in advance if the background was gray or RGB, and position the gray-to-RGB
* transform appropriately, then it would save a lot of work/time.
*/
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
/* If gray -> RGB, do so now only if background is non-gray; else do later
* for performance reasons
*/
if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
!(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_BACKGROUND_SUPPORTED
if ((png_ptr->transformations & PNG_BACKGROUND) &&
((png_ptr->num_trans != 0 ) ||
(png_ptr->color_type & PNG_COLOR_MASK_ALPHA)))
png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1,
&(png_ptr->trans_values), &(png_ptr->background)
#ifdef PNG_READ_GAMMA_SUPPORTED
, &(png_ptr->background_1),
png_ptr->gamma_table, png_ptr->gamma_from_1,
png_ptr->gamma_to_1, png_ptr->gamma_16_table,
png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1,
png_ptr->gamma_shift
#endif
);
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
if ((png_ptr->transformations & PNG_GAMMA) &&
#ifdef PNG_READ_BACKGROUND_SUPPORTED
!((png_ptr->transformations & PNG_BACKGROUND) &&
((png_ptr->num_trans != 0) ||
(png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
#endif
(png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1,
png_ptr->gamma_table, png_ptr->gamma_16_table,
png_ptr->gamma_shift);
#endif
#ifdef 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
#ifdef PNG_READ_DITHER_SUPPORTED
if (png_ptr->transformations & PNG_DITHER)
{
png_do_dither((png_row_infop)&(png_ptr->row_info), png_ptr->row_buf + 1,
png_ptr->palette_lookup, png_ptr->dither_index);
if (png_ptr->row_info.rowbytes == (png_uint_32)0)
png_error(png_ptr, "png_do_dither returned rowbytes=0");
}
#endif
#ifdef PNG_READ_INVERT_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_MONO)
png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#ifdef 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
#ifdef PNG_READ_PACK_SUPPORTED
if (png_ptr->transformations & PNG_PACK)
png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_BGR_SUPPORTED
if (png_ptr->transformations & PNG_BGR)
png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP)
png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
/* If gray -> RGB, do so now only if we did not do so above */
if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_FILLER_SUPPORTED
if (png_ptr->transformations & PNG_FILLER)
png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
(png_uint_32)png_ptr->filler, png_ptr->flags);
#endif
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_ALPHA)
png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_ALPHA)
png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_SWAP_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_BYTES)
png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
if (png_ptr->transformations & PNG_USER_TRANSFORM)
{
if (png_ptr->read_user_transform_fn != NULL)
(*(png_ptr->read_user_transform_fn)) /* User read transform function */
(png_ptr, /* png_ptr */
&(png_ptr->row_info), /* row_info: */
/* png_uint_32 width; width of row */
/* png_uint_32 rowbytes; number of bytes in row */
/* png_byte color_type; color type of pixels */
/* png_byte bit_depth; bit depth of samples */
/* png_byte channels; number of channels (1-4) */
/* png_byte pixel_depth; bits per pixel (depth*channels) */
png_ptr->row_buf + 1); /* start of pixel data for row */
#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
if (png_ptr->user_transform_depth)
png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;
if (png_ptr->user_transform_channels)
png_ptr->row_info.channels = png_ptr->user_transform_channels;
#endif
png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
png_ptr->row_info.channels);
png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
png_ptr->row_info.width);
}
#endif
}
#ifdef 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 /* PRIVATE */
png_do_unpack(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_unpack");
#ifdef PNG_USELESS_TESTS_SUPPORTED
if (row != NULL && row_info != NULL && row_info->bit_depth < 8)
#else
if (row_info->bit_depth < 8)
#endif
{
png_uint_32 i;
png_uint_32 row_width=row_info->width;
switch (row_info->bit_depth)
{
case 1:
{
png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
png_bytep dp = row + (png_size_t)row_width - 1;
png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07);
for (i = 0; i < row_width; i++)
{
*dp = (png_byte)((*sp >> shift) & 0x01);
if (shift == 7)
{
shift = 0;
sp--;
}
else
shift++;
dp--;
}
break;
}
case 2:
{
png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
png_bytep dp = row + (png_size_t)row_width - 1;
png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
for (i = 0; i < row_width; i++)
{
*dp = (png_byte)((*sp >> shift) & 0x03);
if (shift == 6)
{
shift = 0;
sp--;
}
else
shift += 2;
dp--;
}
break;
}
case 4:
{
png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
png_bytep dp = row + (png_size_t)row_width - 1;
png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
for (i = 0; i < row_width; i++)
{
*dp = (png_byte)((*sp >> shift) & 0x0f);
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_width * row_info->channels;
}
}
#endif
#ifdef 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 /* PRIVATE */
png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
{
png_debug(1, "in png_do_unshift");
if (
#ifdef PNG_USELESS_TESTS_SUPPORTED
row != NULL && row_info != NULL && sig_bits != NULL &&
#endif
row_info->color_type != PNG_COLOR_TYPE_PALETTE)
{
int shift[4];
int channels = 0;
int c;
png_uint_16 value = 0;
png_uint_32 row_width = row_info->width;
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;
}
for (c = 0; c < channels; c++)
{
if (shift[c] <= 0)
shift[c] = 0;
else
value = 1;
}
if (!value)
return;
switch (row_info->bit_depth)
{
case 2:
{
png_bytep bp;
png_uint_32 i;
png_uint_32 istop = row_info->rowbytes;
for (bp = row, i = 0; i < istop; i++)
{
*bp >>= 1;
*bp++ &= 0x55;
}
break;
}
case 4:
{
png_bytep bp = row;
png_uint_32 i;
png_uint_32 istop = row_info->rowbytes;
png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) |
(png_byte)((int)0xf >> shift[0]));
for (i = 0; i < istop; i++)
{
*bp >>= shift[0];
*bp++ &= mask;
}
break;
}
case 8:
{
png_bytep bp = row;
png_uint_32 i;
png_uint_32 istop = row_width * channels;
for (i = 0; i < istop; i++)
{
*bp++ >>= shift[i%channels];
}
break;
}
case 16:
{
png_bytep bp = row;
png_uint_32 i;
png_uint_32 istop = channels * row_width;
for (i = 0; i < istop; i++)
{
value = (png_uint_16)((*bp << 8) + *(bp + 1));
value >>= shift[i%channels];
*bp++ = (png_byte)(value >> 8);
*bp++ = (png_byte)(value & 0xff);
}
break;
}
}
}
}
#endif
#ifdef PNG_READ_16_TO_8_SUPPORTED
/* Chop rows of bit depth 16 down to 8 */
void /* PRIVATE */
png_do_chop(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_chop");
#ifdef PNG_USELESS_TESTS_SUPPORTED
if (row != NULL && row_info != NULL && row_info->bit_depth == 16)
#else
if (row_info->bit_depth == 16)
#endif
{
png_bytep sp = row;
png_bytep dp = row;
png_uint_32 i;
png_uint_32 istop = row_info->width * row_info->channels;
for (i = 0; i<istop; i++, sp += 2, dp++)
{
#ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
/* This does a more accurate scaling of the 16-bit color
* value, rather than a simple low-byte truncation.
*
* What the ideal calculation should be:
* *dp = (((((png_uint_32)(*sp) << 8) |
* (png_uint_32)(*(sp + 1))) * 255 + 127)
* / (png_uint_32)65535L;
*
* GRR: no, I think this is what it really should be:
* *dp = (((((png_uint_32)(*sp) << 8) |
* (png_uint_32)(*(sp + 1))) + 128L)
* / (png_uint_32)257L;
*
* GRR: here's the exact calculation with shifts:
* temp = (((png_uint_32)(*sp) << 8) |
* (png_uint_32)(*(sp + 1))) + 128L;
* *dp = (temp - (temp >> 8)) >> 8;
*
* Approximate calculation with shift/add instead of multiply/divide:
* *dp = ((((png_uint_32)(*sp) << 8) |
* (png_uint_32)((int)(*(sp + 1)) - *sp)) + 128) >> 8;
*
* What we actually do to avoid extra shifting and conversion:
*/
*dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0);
#else
/* Simply discard the low order byte */
*dp = *sp;
#endif
}
row_info->bit_depth = 8;
row_info->pixel_depth = (png_byte)(8 * row_info->channels);
row_info->rowbytes = row_info->width * row_info->channels;
}
}
#endif
#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
void /* PRIVATE */
png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_read_swap_alpha");
#ifdef PNG_USELESS_TESTS_SUPPORTED
if (row != NULL && row_info != NULL)
#endif
{
png_uint_32 row_width = row_info->width;
if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
{
/* This converts from RGBA to ARGB */
if (row_info->bit_depth == 8)
{
png_bytep sp = row + row_info->rowbytes;
png_bytep dp = sp;
png_byte save;
png_uint_32 i;
for (i = 0; i < row_width; i++)
{
save = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = save;
}
}
/* This converts from RRGGBBAA to AARRGGBB */
else
{
png_bytep sp = row + row_info->rowbytes;
png_bytep dp = sp;
png_byte save[2];
png_uint_32 i;
for (i = 0; i < row_width; i++)
{
save[0] = *(--sp);
save[1] = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = save[0];
*(--dp) = save[1];
}
}
}
else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
{
/* This converts from GA to AG */
if (row_info->bit_depth == 8)
{
png_bytep sp = row + row_info->rowbytes;
png_bytep dp = sp;
png_byte save;
png_uint_32 i;
for (i = 0; i < row_width; i++)
{
save = *(--sp);
*(--dp) = *(--sp);
*(--dp) = save;
}
}
/* This converts from GGAA to AAGG */
else
{
png_bytep sp = row + row_info->rowbytes;
png_bytep dp = sp;
png_byte save[2];
png_uint_32 i;
for (i = 0; i < row_width; i++)
{
save[0] = *(--sp);
save[1] = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = save[0];
*(--dp) = save[1];
}
}
}
}
}
#endif
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
void /* PRIVATE */
png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_read_invert_alpha");
#ifdef PNG_USELESS_TESTS_SUPPORTED
if (row != NULL && row_info != NULL)
#endif
{
png_uint_32 row_width = row_info->width;
if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
{
/* This inverts the alpha channel in RGBA */
if (row_info->bit_depth == 8)
{
png_bytep sp = row + row_info->rowbytes;
png_bytep dp = sp;
png_uint_32 i;
for (i = 0; i < row_width; i++)
{
*(--dp) = (png_byte)(255 - *(--sp));
/* This does nothing:
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
We can replace it with:
*/
sp-=3;
dp=sp;
}
}
/* This inverts the alpha channel in RRGGBBAA */
else
{
png_bytep sp = row + row_info->rowbytes;
png_bytep dp = sp;
png_uint_32 i;
for (i = 0; i < row_width; i++)
{
*(--dp) = (png_byte)(255 - *(--sp));
*(--dp) = (png_byte)(255 - *(--sp));
/* This does nothing:
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
We can replace it with:
*/
sp-=6;
dp=sp;
}
}
}
else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
{
/* This inverts the alpha channel in GA */
if (row_info->bit_depth == 8)
{
png_bytep sp = row + row_info->rowbytes;
png_bytep dp = sp;
png_uint_32 i;
for (i = 0; i < row_width; i++)
{
*(--dp) = (png_byte)(255 - *(--sp));
*(--dp) = *(--sp);
}
}
/* This inverts the alpha channel in GGAA */
else
{
png_bytep sp = row + row_info->rowbytes;
png_bytep dp = sp;
png_uint_32 i;
for (i = 0; i < row_width; i++)
{
*(--dp) = (png_byte)(255 - *(--sp));
*(--dp) = (png_byte)(255 - *(--sp));
/*
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*/
sp-=2;
dp=sp;
}
}
}
}
}
#endif
#ifdef PNG_READ_FILLER_SUPPORTED
/* Add filler channel if we have RGB color */
void /* PRIVATE */
png_do_read_filler(png_row_infop row_info, png_bytep row,
png_uint_32 filler, png_uint_32 flags)
{
png_uint_32 i;
png_uint_32 row_width = row_info->width;
png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
png_byte lo_filler = (png_byte)(filler & 0xff);
png_debug(1, "in png_do_read_filler");
if (
#ifdef PNG_USELESS_TESTS_SUPPORTED
row != NULL && row_info != NULL &&
#endif
row_info->color_type == PNG_COLOR_TYPE_GRAY)
{
if (row_info->bit_depth == 8)
{
/* This changes the data from G to GX */
if (flags & PNG_FLAG_FILLER_AFTER)
{
png_bytep sp = row + (png_size_t)row_width;
png_bytep dp = sp + (png_size_t)row_width;
for (i = 1; i < row_width; i++)
{
*(--dp) = lo_filler;
*(--dp) = *(--sp);
}
*(--dp) = lo_filler;
row_info->channels = 2;
row_info->pixel_depth = 16;
row_info->rowbytes = row_width * 2;
}
/* This changes the data from G to XG */
else
{
png_bytep sp = row + (png_size_t)row_width;
png_bytep dp = sp + (png_size_t)row_width;
for (i = 0; i < row_width; i++)
{
*(--dp) = *(--sp);
*(--dp) = lo_filler;
}
row_info->channels = 2;
row_info->pixel_depth = 16;
row_info->rowbytes = row_width * 2;
}
}
else if (row_info->bit_depth == 16)
{
/* This changes the data from GG to GGXX */
if (flags & PNG_FLAG_FILLER_AFTER)
{
png_bytep sp = row + (png_size_t)row_width * 2;
png_bytep dp = sp + (png_size_t)row_width * 2;
for (i = 1; i < row_width; i++)
{
*(--dp) = hi_filler;
*(--dp) = lo_filler;
*(--dp) = *(--sp);
*(--dp) = *(--sp);
}
*(--dp) = hi_filler;
*(--dp) = lo_filler;
row_info->channels = 2;
row_info->pixel_depth = 32;
row_info->rowbytes = row_width * 4;
}
/* This changes the data from GG to XXGG */
else
{
png_bytep sp = row + (png_size_t)row_width * 2;
png_bytep dp = sp + (png_size_t)row_width * 2;
for (i = 0; i < row_width; i++)
{
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = hi_filler;
*(--dp) = lo_filler;
}
row_info->channels = 2;
row_info->pixel_depth = 32;
row_info->rowbytes = row_width * 4;
}
}
} /* COLOR_TYPE == GRAY */
else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
{
if (row_info->bit_depth == 8)
{
/* This changes the data from RGB to RGBX */
if (flags & PNG_FLAG_FILLER_AFTER)
{
png_bytep sp = row + (png_size_t)row_width * 3;
png_bytep dp = sp + (png_size_t)row_width;
for (i = 1; i < row_width; i++)
{
*(--dp) = lo_filler;
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
}
*(--dp) = lo_filler;
row_info->channels = 4;
row_info->pixel_depth = 32;
row_info->rowbytes = row_width * 4;
}
/* This changes the data from RGB to XRGB */
else
{
png_bytep sp = row + (png_size_t)row_width * 3;
png_bytep dp = sp + (png_size_t)row_width;
for (i = 0; i < row_width; i++)
{
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = lo_filler;
}
row_info->channels = 4;
row_info->pixel_depth = 32;
row_info->rowbytes = row_width * 4;
}
}
else if (row_info->bit_depth == 16)
{
/* This changes the data from RRGGBB to RRGGBBXX */
if (flags & PNG_FLAG_FILLER_AFTER)
{
png_bytep sp = row + (png_size_t)row_width * 6;
png_bytep dp = sp + (png_size_t)row_width * 2;
for (i = 1; i < row_width; i++)
{
*(--dp) = hi_filler;
*(--dp) = lo_filler;
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
}
*(--dp) = hi_filler;
*(--dp) = lo_filler;
row_info->channels = 4;
row_info->pixel_depth = 64;
row_info->rowbytes = row_width * 8;
}
/* This changes the data from RRGGBB to XXRRGGBB */
else
{
png_bytep sp = row + (png_size_t)row_width * 6;
png_bytep dp = sp + (png_size_t)row_width * 2;
for (i = 0; i < row_width; i++)
{
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = *(--sp);
*(--dp) = hi_filler;
*(--dp) = lo_filler;
}
row_info->channels = 4;
row_info->pixel_depth = 64;
row_info->rowbytes = row_width * 8;
}
}
} /* COLOR_TYPE == RGB */
}
#endif
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
/* Expand grayscale files to RGB, with or without alpha */
void /* PRIVATE */
png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
{
png_uint_32 i;
png_uint_32 row_width = row_info->width;
png_debug(1, "in png_do_gray_to_rgb");
if (row_info->bit_depth >= 8 &&
#ifdef PNG_USELESS_TESTS_SUPPORTED
row != NULL && row_info != NULL &&
#endif
!(row_info->color_type & PNG_COLOR_MASK_COLOR))
{
if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
{
if (row_info->bit_depth == 8)
{
png_bytep sp = row + (png_size_t)row_width - 1;
png_bytep dp = sp + (png_size_t)row_width * 2;
for (i = 0; i < row_width; i++)
{
*(dp--) = *sp;
*(dp--) = *sp;
*(dp--) = *(sp--);
}
}
else
{
png_bytep sp = row + (png_size_t)row_width * 2 - 1;
png_bytep dp = sp + (png_size_t)row_width * 4;
for (i = 0; i < row_width; i++)
{
*(dp--) = *sp;
*(dp--) = *(sp - 1);
*(dp--) = *sp;
*(dp--) = *(sp - 1);
*(dp--) = *(sp--);
*(dp--) = *(sp--);
}
}
}
else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
{
if (row_info->bit_depth == 8)
{
png_bytep sp = row + (png_size_t)row_width * 2 - 1;
png_bytep dp = sp + (png_size_t)row_width * 2;
for (i = 0; i < row_width; i++)
{
*(dp--) = *(sp--);
*(dp--) = *sp;
*(dp--) = *sp;
*(dp--) = *(sp--);
}
}
else
{
png_bytep sp = row + (png_size_t)row_width * 4 - 1;
png_bytep dp = sp + (png_size_t)row_width * 4;
for (i = 0; i < row_width; i++)
{
*(dp--) = *(sp--);
*(dp--) = *(sp--);
*(dp--) = *sp;
*(dp--) = *(sp - 1);
*(dp--) = *sp;
*(dp--) = *(sp - 1);
*(dp--) = *(sp--);
*(dp--) = *(sp--);
}
}
}
row_info->channels += (png_byte)2;
row_info->color_type |= PNG_COLOR_MASK_COLOR;
row_info->pixel_depth = (png_byte)(row_info->channels *
row_info->bit_depth);
row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
}
}
#endif
#ifdef 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/> (THIS LINK IS DEAD June 2008)
* New link:
* <http://www.poynton.com/notes/colour_and_gamma/>
* Charles Poynton poynton at poynton.com
*
* 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_gray");
if (
#ifdef 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;
png_byte hi,lo;
hi=*(sp)++; lo=*(sp)++;
red = (png_uint_16)((hi << 8) | (lo));
hi=*(sp)++; lo=*(sp)++;
green = (png_uint_16)((hi << 8) | (lo));
hi=*(sp)++; lo=*(sp)++;
blue = (png_uint_16)((hi << 8) | (lo));
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;
png_byte hi,lo;
hi=*(sp)++; lo=*(sp)++;
red = (png_uint_16)((hi << 8) | (lo));
hi=*(sp)++; lo=*(sp)++;
green = (png_uint_16)((hi << 8) | (lo));
hi=*(sp)++; lo=*(sp)++;
blue = (png_uint_16)((hi << 8) | (lo));
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;
png_byte hi,lo;
hi=*(sp)++; lo=*(sp)++;
red = (png_uint_16)((hi << 8) | (lo));
hi=*(sp)++; lo=*(sp)++;
green = (png_uint_16)((hi << 8) | (lo));
hi=*(sp)++; lo=*(sp)++;
blue = (png_uint_16)((hi << 8) | (lo));
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_palette");
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_palette");
#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;