diff options
Diffstat (limited to 'third_party/lpng_v163/pngrtran.c')
| -rw-r--r-- | third_party/lpng_v163/pngrtran.c | 5102 |
1 files changed, 0 insertions, 5102 deletions
diff --git a/third_party/lpng_v163/pngrtran.c b/third_party/lpng_v163/pngrtran.c deleted file mode 100644 index a81034cdf1..0000000000 --- a/third_party/lpng_v163/pngrtran.c +++ /dev/null @@ -1,5102 +0,0 @@ -/* pngrtran.c - transforms the data in a row for PNG readers
- *
- * Last changed in libpng 1.6.2 [April 25, 2013]
- * Copyright (c) 1998-2013 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.
- */
-
-#include "pngpriv.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_structrp 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;
- }
-}
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-/* Is it OK to set a transformation now? Only if png_start_read_image or
- * png_read_update_info have not been called. It is not necessary for the IHDR
- * to have been read in all cases, the parameter allows for this check too.
- */
-static int
-png_rtran_ok(png_structrp png_ptr, int need_IHDR)
-{
- if (png_ptr != NULL)
- {
- if (png_ptr->flags & PNG_FLAG_ROW_INIT)
- png_app_error(png_ptr,
- "invalid after png_start_read_image or png_read_update_info");
-
- else if (need_IHDR && (png_ptr->mode & PNG_HAVE_IHDR) == 0)
- png_app_error(png_ptr, "invalid before the PNG header has been read");
-
- else
- {
- /* Turn on failure to initialize correctly for all transforms. */
- png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
-
- return 1; /* Ok */
- }
- }
-
- return 0; /* no png_error possible! */
-}
-#endif
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-/* Handle alpha and tRNS via a background color */
-void PNGFAPI
-png_set_background_fixed(png_structrp png_ptr,
- png_const_color_16p background_color, int background_gamma_code,
- int need_expand, png_fixed_point background_gamma)
-{
- png_debug(1, "in png_set_background_fixed");
-
- if (!png_rtran_ok(png_ptr, 0) || background_color == 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_COMPOSE | PNG_STRIP_ALPHA;
- png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
- png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-
- png_ptr->background = *background_color;
- png_ptr->background_gamma = background_gamma;
- png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
- if (need_expand)
- png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
- else
- png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
-}
-
-# ifdef PNG_FLOATING_POINT_SUPPORTED
-void PNGAPI
-png_set_background(png_structrp png_ptr,
- png_const_color_16p background_color, int background_gamma_code,
- int need_expand, double background_gamma)
-{
- png_set_background_fixed(png_ptr, background_color, background_gamma_code,
- need_expand, png_fixed(png_ptr, background_gamma, "png_set_background"));
-}
-# endif /* FLOATING_POINT */
-#endif /* READ_BACKGROUND */
-
-/* Scale 16-bit depth files to 8-bit depth. If both of these are set then the
- * one that pngrtran does first (scale) happens. This is necessary to allow the
- * TRANSFORM and API behavior to be somewhat consistent, and it's simpler.
- */
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-void PNGAPI
-png_set_scale_16(png_structrp png_ptr)
-{
- png_debug(1, "in png_set_scale_16");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- png_ptr->transformations |= PNG_SCALE_16_TO_8;
-}
-#endif
-
-#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-/* Chop 16-bit depth files to 8-bit depth */
-void PNGAPI
-png_set_strip_16(png_structrp png_ptr)
-{
- png_debug(1, "in png_set_strip_16");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- png_ptr->transformations |= PNG_16_TO_8;
-}
-#endif
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-void PNGAPI
-png_set_strip_alpha(png_structrp png_ptr)
-{
- png_debug(1, "in png_set_strip_alpha");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- png_ptr->transformations |= PNG_STRIP_ALPHA;
-}
-#endif
-
-#if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
-static png_fixed_point
-translate_gamma_flags(png_structrp png_ptr, png_fixed_point output_gamma,
- int is_screen)
-{
- /* Check for flag values. The main reason for having the old Mac value as a
- * flag is that it is pretty near impossible to work out what the correct
- * value is from Apple documentation - a working Mac system is needed to
- * discover the value!
- */
- if (output_gamma == PNG_DEFAULT_sRGB ||
- output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
- {
- /* If there is no sRGB support this just sets the gamma to the standard
- * sRGB value. (This is a side effect of using this function!)
- */
-# ifdef PNG_READ_sRGB_SUPPORTED
- png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
-# else
- PNG_UNUSED(png_ptr)
-# endif
- if (is_screen)
- output_gamma = PNG_GAMMA_sRGB;
- else
- output_gamma = PNG_GAMMA_sRGB_INVERSE;
- }
-
- else if (output_gamma == PNG_GAMMA_MAC_18 ||
- output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18)
- {
- if (is_screen)
- output_gamma = PNG_GAMMA_MAC_OLD;
- else
- output_gamma = PNG_GAMMA_MAC_INVERSE;
- }
-
- return output_gamma;
-}
-
-# ifdef PNG_FLOATING_POINT_SUPPORTED
-static png_fixed_point
-convert_gamma_value(png_structrp png_ptr, double output_gamma)
-{
- /* The following silently ignores cases where fixed point (times 100,000)
- * gamma values are passed to the floating point API. This is safe and it
- * means the fixed point constants work just fine with the floating point
- * API. The alternative would just lead to undetected errors and spurious
- * bug reports. Negative values fail inside the _fixed API unless they
- * correspond to the flag values.
- */
- if (output_gamma > 0 && output_gamma < 128)
- output_gamma *= PNG_FP_1;
-
- /* This preserves -1 and -2 exactly: */
- output_gamma = floor(output_gamma + .5);
-
- if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN)
- png_fixed_error(png_ptr, "gamma value");
-
- return (png_fixed_point)output_gamma;
-}
-# endif
-#endif /* READ_ALPHA_MODE || READ_GAMMA */
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-void PNGFAPI
-png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
- png_fixed_point output_gamma)
-{
- int compose = 0;
- png_fixed_point file_gamma;
-
- png_debug(1, "in png_set_alpha_mode");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
-
- /* Validate the value to ensure it is in a reasonable range. The value
- * is expected to be 1 or greater, but this range test allows for some
- * viewing correction values. The intent is to weed out users of this API
- * who use the inverse of the gamma value accidentally! Since some of these
- * values are reasonable this may have to be changed.
- */
- if (output_gamma < 70000 || output_gamma > 300000)
- png_error(png_ptr, "output gamma out of expected range");
-
- /* The default file gamma is the inverse of the output gamma; the output
- * gamma may be changed below so get the file value first:
- */
- file_gamma = png_reciprocal(output_gamma);
-
- /* There are really 8 possibilities here, composed of any combination
- * of:
- *
- * premultiply the color channels
- * do not encode non-opaque pixels
- * encode the alpha as well as the color channels
- *
- * The differences disappear if the input/output ('screen') gamma is 1.0,
- * because then the encoding is a no-op and there is only the choice of
- * premultiplying the color channels or not.
- *
- * png_set_alpha_mode and png_set_background interact because both use
- * png_compose to do the work. Calling both is only useful when
- * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along
- * with a default gamma value. Otherwise PNG_COMPOSE must not be set.
- */
- switch (mode)
- {
- case PNG_ALPHA_PNG: /* default: png standard */
- /* No compose, but it may be set by png_set_background! */
- png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
- png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
- break;
-
- case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
- compose = 1;
- png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
- png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
- /* The output is linear: */
- output_gamma = PNG_FP_1;
- break;
-
- case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */
- compose = 1;
- png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
- png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA;
- /* output_gamma records the encoding of opaque pixels! */
- break;
-
- case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */
- compose = 1;
- png_ptr->transformations |= PNG_ENCODE_ALPHA;
- png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
- break;
-
- default:
- png_error(png_ptr, "invalid alpha mode");
- }
-
- /* Only set the default gamma if the file gamma has not been set (this has
- * the side effect that the gamma in a second call to png_set_alpha_mode will
- * be ignored.)
- */
- if (png_ptr->colorspace.gamma == 0)
- {
- png_ptr->colorspace.gamma = file_gamma;
- png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
- }
-
- /* But always set the output gamma: */
- png_ptr->screen_gamma = output_gamma;
-
- /* Finally, if pre-multiplying, set the background fields to achieve the
- * desired result.
- */
- if (compose)
- {
- /* And obtain alpha pre-multiplication by composing on black: */
- memset(&png_ptr->background, 0, (sizeof png_ptr->background));
- png_ptr->background_gamma = png_ptr->colorspace.gamma; /* just in case */
- png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
- png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
-
- if (png_ptr->transformations & PNG_COMPOSE)
- png_error(png_ptr,
- "conflicting calls to set alpha mode and background");
-
- png_ptr->transformations |= PNG_COMPOSE;
- }
-}
-
-# ifdef PNG_FLOATING_POINT_SUPPORTED
-void PNGAPI
-png_set_alpha_mode(png_structrp png_ptr, int mode, double output_gamma)
-{
- png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
- output_gamma));
-}
-# endif
-#endif
-
-#ifdef PNG_READ_QUANTIZE_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_quantize" indicates
- * whether we need a quantizing 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 * next;
- png_byte left;
- png_byte right;
-} png_dsort;
-typedef png_dsort * png_dsortp;
-typedef png_dsort * * png_dsortpp;
-
-void PNGAPI
-png_set_quantize(png_structrp png_ptr, png_colorp palette,
- int num_palette, int maximum_colors, png_const_uint_16p histogram,
- int full_quantize)
-{
- png_debug(1, "in png_set_quantize");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- png_ptr->transformations |= PNG_QUANTIZE;
-
- if (!full_quantize)
- {
- int i;
-
- png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
- (png_uint_32)(num_palette * (sizeof (png_byte))));
- for (i = 0; i < num_palette; i++)
- png_ptr->quantize_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->quantize_sort = (png_bytep)png_malloc(png_ptr,
- (png_uint_32)(num_palette * (sizeof (png_byte))));
-
- /* Initialize the quantize_sort array */
- for (i = 0; i < num_palette; i++)
- png_ptr->quantize_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->quantize_sort[j]]
- < histogram[png_ptr->quantize_sort[j + 1]])
- {
- png_byte t;
-
- t = png_ptr->quantize_sort[j];
- png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1];
- png_ptr->quantize_sort[j + 1] = t;
- done = 0;
- }
- }
-
- if (done)
- break;
- }
-
- /* Swap the palette around, and set up a table, if necessary */
- if (full_quantize)
- {
- 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->quantize_sort[i] >= maximum_colors)
- {
- do
- j--;
- while ((int)png_ptr->quantize_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->quantize_sort[i] >= maximum_colors)
- {
- png_color tmp_color;
-
- do
- j--;
- while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
-
- tmp_color = palette[j];
- palette[j] = palette[i];
- palette[i] = tmp_color;
- /* Indicate where the color went */
- png_ptr->quantize_index[j] = (png_byte)i;
- png_ptr->quantize_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->quantize_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->quantize_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->quantize_index[i] = (png_byte)min_k;
- }
- }
- }
- png_free(png_ptr, png_ptr->quantize_sort);
- png_ptr->quantize_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 * (sizeof (png_byte))));
- png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
- (png_uint_32)(num_palette * (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 *
- (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)(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_quantize)
- {
- int k;
-
- for (k = 0; k < num_palette; k++)
- {
- if (png_ptr->quantize_index[k] ==
- png_ptr->index_to_palette[j])
- png_ptr->quantize_index[k] =
- png_ptr->index_to_palette[next_j];
-
- if ((int)png_ptr->quantize_index[k] ==
- num_new_palette)
- png_ptr->quantize_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_quantize)
- {
- int i;
- png_bytep distance;
- int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS +
- PNG_QUANTIZE_BLUE_BITS;
- int num_red = (1 << PNG_QUANTIZE_RED_BITS);
- int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
- int num_blue = (1 << PNG_QUANTIZE_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 * (sizeof (png_byte))));
-
- distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *
- (sizeof (png_byte))));
-
- memset(distance, 0xff, num_entries * (sizeof (png_byte)));
-
- for (i = 0; i < num_palette; i++)
- {
- int ir, ig, ib;
- int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS));
- int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS));
- int b = (palette[i].blue >> (8 - PNG_QUANTIZE_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_QUANTIZE_BLUE_BITS +
- PNG_QUANTIZE_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_QUANTIZE_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 /* PNG_READ_QUANTIZE_SUPPORTED */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-void PNGFAPI
-png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
- png_fixed_point file_gamma)
-{
- png_debug(1, "in png_set_gamma_fixed");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- /* New in libpng-1.5.4 - reserve particular negative values as flags. */
- scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
- file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
-
- /* Checking the gamma values for being >0 was added in 1.5.4 along with the
- * premultiplied alpha support; this actually hides an undocumented feature
- * of the previous implementation which allowed gamma processing to be
- * disabled in background handling. There is no evidence (so far) that this
- * was being used; however, png_set_background itself accepted and must still
- * accept '0' for the gamma value it takes, because it isn't always used.
- *
- * Since this is an API change (albeit a very minor one that removes an
- * undocumented API feature) the following checks were only enabled in
- * libpng-1.6.0.
- */
- if (file_gamma <= 0)
- png_error(png_ptr, "invalid file gamma in png_set_gamma");
-
- if (scrn_gamma <= 0)
- png_error(png_ptr, "invalid screen gamma in png_set_gamma");
-
- /* Set the gamma values unconditionally - this overrides the value in the PNG
- * file if a gAMA chunk was present. png_set_alpha_mode provides a
- * different, easier, way to default the file gamma.
- */
- png_ptr->colorspace.gamma = file_gamma;
- png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
- png_ptr->screen_gamma = scrn_gamma;
-}
-
-# ifdef PNG_FLOATING_POINT_SUPPORTED
-void PNGAPI
-png_set_gamma(png_structrp png_ptr, double scrn_gamma, double file_gamma)
-{
- png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
- convert_gamma_value(png_ptr, file_gamma));
-}
-# endif /* FLOATING_POINT_SUPPORTED */
-#endif /* READ_GAMMA */
-
-#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_structrp png_ptr)
-{
- png_debug(1, "in png_set_expand");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
-}
-
-/* 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_structrp png_ptr)
-{
- png_debug(1, "in png_set_palette_to_rgb");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
-}
-
-/* Expand grayscale images of less than 8-bit depth to 8 bits. */
-void PNGAPI
-png_set_expand_gray_1_2_4_to_8(png_structrp png_ptr)
-{
- png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- png_ptr->transformations |= PNG_EXPAND;
-}
-
-/* Expand tRNS chunks to alpha channels. */
-void PNGAPI
-png_set_tRNS_to_alpha(png_structrp png_ptr)
-{
- png_debug(1, "in png_set_tRNS_to_alpha");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
-}
-#endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
- * it may not work correctly.)
- */
-void PNGAPI
-png_set_expand_16(png_structrp png_ptr)
-{
- png_debug(1, "in png_set_expand_16");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
-}
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-void PNGAPI
-png_set_gray_to_rgb(png_structrp png_ptr)
-{
- png_debug(1, "in png_set_gray_to_rgb");
-
- if (!png_rtran_ok(png_ptr, 0))
- return;
-
- /* Because rgb must be 8 bits or more: */
- png_set_expand_gray_1_2_4_to_8(png_ptr);
- png_ptr->transformations |= PNG_GRAY_TO_RGB;
-}
-#endif
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-void PNGFAPI
-png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
- png_fixed_point red, png_fixed_point green)
-{
- png_debug(1, "in png_set_rgb_to_gray");
-
- /* Need the IHDR here because of the check on color_type below. */
- /* TODO: fix this */
- if (!png_rtran_ok(png_ptr, 1))
- return;
-
- switch(error_action)
- {
- case PNG_ERROR_ACTION_NONE:
- png_ptr->transformations |= PNG_RGB_TO_GRAY;
- break;
-
- case PNG_ERROR_ACTION_WARN:
- png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
- break;
-
- case PNG_ERROR_ACTION_ERROR:
- png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
- break;
-
- default:
- png_error(png_ptr, "invalid error action to rgb_to_gray");
- break;
- }
-
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-#ifdef PNG_READ_EXPAND_SUPPORTED
- png_ptr->transformations |= PNG_EXPAND;
-#else
- {
- /* Make this an error in 1.6 because otherwise the application may assume
- * that it just worked and get a memory overwrite.
- */
- png_error(png_ptr,
- "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
-
- /* png_ptr->transformations &= ~PNG_RGB_TO_GRAY; */
- }
-#endif
- {
- if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
- {
- png_uint_16 red_int, green_int;
-
- /* NOTE: this calculation does not round, but this behavior is retained
- * for consistency, the inaccuracy is very small. The code here always
- * overwrites the coefficients, regardless of whether they have been
- * defaulted or set already.
- */
- red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
- green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
-
- png_ptr->rgb_to_gray_red_coeff = red_int;
- png_ptr->rgb_to_gray_green_coeff = green_int;
- png_ptr->rgb_to_gray_coefficients_set = 1;
- }
-
- else
- {
- if (red >= 0 && green >= 0)
- png_app_warning(png_ptr,
- "ignoring out of range rgb_to_gray coefficients");
-
- /* Use the defaults, from the cHRM chunk if set, else the historical
- * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See
- * png_do_rgb_to_gray for more discussion of the values. In this case
- * the coefficients are not marked as 'set' and are not overwritten if
- * something has already provided a default.
- */
- if (png_ptr->rgb_to_gray_red_coeff == 0 &&
- png_ptr->rgb_to_gray_green_coeff == 0)
- {
- png_ptr->rgb_to_gray_red_coeff = 6968;
- png_ptr->rgb_to_gray_green_coeff = 23434;
- /* png_ptr->rgb_to_gray_blue_coeff = 2366; */
- }
- }
- }
-}
-
-#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_structrp png_ptr, int error_action, double red,
- double green)
-{
- png_set_rgb_to_gray_fixed(png_ptr, error_action,
- png_fixed(png_ptr, red, "rgb to gray red coefficient"),
- png_fixed(png_ptr, green, "rgb to gray green coefficient"));
-}
-#endif /* FLOATING POINT */
-
-#endif /* RGB_TO_GRAY */
-
-#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
- defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
-void PNGAPI
-png_set_read_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
- read_user_transform_fn)
-{
- png_debug(1, "in png_set_read_user_transform_fn");
-
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
- png_ptr->transformations |= PNG_USER_TRANSFORM;
- png_ptr->read_user_transform_fn = read_user_transform_fn;
-#endif
-}
-#endif
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-#ifdef PNG_READ_GAMMA_SUPPORTED
-/* In the case of gamma transformations 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.
- */
-static int /* PRIVATE */
-png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
-{
- /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
- * correction as a difference of the overall transform from 1.0
- *
- * We want to compare the threshold with s*f - 1, if we get
- * overflow here it is because of wacky gamma values so we
- * turn on processing anyway.
- */
- png_fixed_point gtest;
- return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) ||
- png_gamma_significant(gtest);
-}
-#endif
-
-/* Initialize everything needed for the read. This includes modifying
- * the palette.
- */
-
-/*For the moment 'png_init_palette_transformations' and
- * 'png_init_rgb_transformations' only do some flag canceling optimizations.
- * The intent is that these two routines should have palette or rgb operations
- * extracted from 'png_init_read_transformations'.
- */
-static void /* PRIVATE */
-png_init_palette_transformations(png_structrp png_ptr)
-{
- /* Called to handle the (input) palette case. In png_do_read_transformations
- * the first step is to expand the palette if requested, so this code must
- * take care to only make changes that are invariant with respect to the
- * palette expansion, or only do them if there is no expansion.
- *
- * STRIP_ALPHA has already been handled in the caller (by setting num_trans
- * to 0.)
- */
- int input_has_alpha = 0;
- int input_has_transparency = 0;
-
- if (png_ptr->num_trans > 0)
- {
- int i;
-
- /* Ignore if all the entries are opaque (unlikely!) */
- for (i=0; i<png_ptr->num_trans; ++i)
- if (png_ptr->trans_alpha[i] == 255)
- continue;
- else if (png_ptr->trans_alpha[i] == 0)
- input_has_transparency = 1;
- else
- input_has_alpha = 1;
- }
-
- /* If no alpha we can optimize. */
- if (!input_has_alpha)
- {
- /* Any alpha means background and associative alpha processing is
- * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA
- * and ENCODE_ALPHA are irrelevant.
- */
- png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
- png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-
- if (!input_has_transparency)
- png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
- }
-
-#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
- /* png_set_background handling - deals with the complexity of whether the
- * background color is in the file format or the screen format in the case
- * where an 'expand' will happen.
- */
-
- /* The following code cannot be entered in the alpha pre-multiplication case
- * because PNG_BACKGROUND_EXPAND is cancelled below.
- */
- if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
- (png_ptr->transformations & PNG_EXPAND))
- {
- {
- 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)
- {
- if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
- {
- /* Invert the alpha channel (in tRNS) unless the pixels are
- * going to be expanded, in which case leave it for later
- */
- int i, istop = png_ptr->num_trans;
-
- for (i=0; i<istop; i++)
- png_ptr->trans_alpha[i] = (png_byte)(255 -
- png_ptr->trans_alpha[i]);
- }
- }
-#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
- }
- } /* background expand and (therefore) no alpha association. */
-#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
-}
-
-static void /* PRIVATE */
-png_init_rgb_transformations(png_structrp png_ptr)
-{
- /* Added to libpng-1.5.4: check the color type to determine whether there
- * is any alpha or transparency in the image and simply cancel the
- * background and alpha mode stuff if there isn't.
- */
- int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
- int input_has_transparency = png_ptr->num_trans > 0;
-
- /* If no alpha we can optimize. */
- if (!input_has_alpha)
- {
- /* Any alpha means background and associative alpha processing is
- * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA
- * and ENCODE_ALPHA are irrelevant.
- */
-# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
- png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-# endif
-
- if (!input_has_transparency)
- png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
- }
-
-#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
- /* png_set_background handling - deals with the complexity of whether the
- * background color is in the file format or the screen format in the case
- * where an 'expand' will happen.
- */
-
- /* The following code cannot be entered in the alpha pre-multiplication case
- * because PNG_BACKGROUND_EXPAND is cancelled below.
- */
- if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
- (png_ptr->transformations & PNG_EXPAND) &&
- !(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
- /* i.e., GRAY or GRAY_ALPHA */
- {
- {
- /* Expand background and tRNS chunks */
- int gray = png_ptr->background.gray;
- int trans_gray = png_ptr->trans_color.gray;
-
- switch (png_ptr->bit_depth)
- {
- case 1:
- gray *= 0xff;
- trans_gray *= 0xff;
- break;
-
- case 2:
- gray *= 0x55;
- trans_gray *= 0x55;
- break;
-
- case 4:
- gray *= 0x11;
- trans_gray *= 0x11;
- break;
-
- default:
-
- case 8:
- /* FALL THROUGH (Already 8 bits) */
-
- case 16:
- /* Already a full 16 bits */
- break;
- }
-
- png_ptr->background.red = png_ptr->background.green =
- png_ptr->background.blue = (png_uint_16)gray;
-
- if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
- {
- png_ptr->trans_color.red = png_ptr->trans_color.green =
- png_ptr->trans_color.blue = (png_uint_16)trans_gray;
- }
- }
- } /* background expand and (therefore) no alpha association. */
-#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
-}
-
-void /* PRIVATE */
-png_init_read_transformations(png_structrp png_ptr)
-{
- png_debug(1, "in png_init_read_transformations");
-
- /* This internal function is called from png_read_start_row in pngrutil.c
- * and it is called before the 'rowbytes' calculation is done, so the code
- * in here can change or update the transformations flags.
- *
- * First do updates that do not depend on the details of the PNG image data
- * being processed.
- */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
- /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
- * png_set_alpha_mode and this is another source for a default file gamma so
- * the test needs to be performed later - here. In addition prior to 1.5.4
- * the tests were repeated for the PALETTE color type here - this is no
- * longer necessary (and doesn't seem to have been necessary before.)
- */
- {
- /* The following temporary indicates if overall gamma correction is
- * required.
- */
- int gamma_correction = 0;
-
- if (png_ptr->colorspace.gamma != 0) /* has been set */
- {
- if (png_ptr->screen_gamma != 0) /* screen set too */
- gamma_correction = png_gamma_threshold(png_ptr->colorspace.gamma,
- png_ptr->screen_gamma);
-
- else
- /* Assume the output matches the input; a long time default behavior
- * of libpng, although the standard has nothing to say about this.
- */
- png_ptr->screen_gamma = png_reciprocal(png_ptr->colorspace.gamma);
- }
-
- else if (png_ptr->screen_gamma != 0)
- /* The converse - assume the file matches the screen, note that this
- * perhaps undesireable default can (from 1.5.4) be changed by calling
- * png_set_alpha_mode (even if the alpha handling mode isn't required
- * or isn't changed from the default.)
- */
- png_ptr->colorspace.gamma = png_reciprocal(png_ptr->screen_gamma);
-
- else /* neither are set */
- /* Just in case the following prevents any processing - file and screen
- * are both assumed to be linear and there is no way to introduce a
- * third gamma value other than png_set_background with 'UNIQUE', and,
- * prior to 1.5.4
- */
- png_ptr->screen_gamma = png_ptr->colorspace.gamma = PNG_FP_1;
-
- /* We have a gamma value now. */
- png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
-
- /* Now turn the gamma transformation on or off as appropriate. Notice
- * that PNG_GAMMA just refers to the file->screen correction. Alpha
- * composition may independently cause gamma correction because it needs
- * linear data (e.g. if the file has a gAMA chunk but the screen gamma
- * hasn't been specified.) In any case this flag may get turned off in
- * the code immediately below if the transform can be handled outside the
- * row loop.
- */
- if (gamma_correction)
- png_ptr->transformations |= PNG_GAMMA;
-
- else
- png_ptr->transformations &= ~PNG_GAMMA;
- }
-#endif
-
- /* Certain transformations have the effect of preventing other
- * transformations that happen afterward in png_do_read_transformations,
- * resolve the interdependencies here. From the code of
- * png_do_read_transformations the order is:
- *
- * 1) PNG_EXPAND (including PNG_EXPAND_tRNS)
- * 2) PNG_STRIP_ALPHA (if no compose)
- * 3) PNG_RGB_TO_GRAY
- * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
- * 5) PNG_COMPOSE
- * 6) PNG_GAMMA
- * 7) PNG_STRIP_ALPHA (if compose)
- * 8) PNG_ENCODE_ALPHA
- * 9) PNG_SCALE_16_TO_8
- * 10) PNG_16_TO_8
- * 11) PNG_QUANTIZE (converts to palette)
- * 12) PNG_EXPAND_16
- * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
- * 14) PNG_INVERT_MONO
- * 15) PNG_SHIFT
- * 16) PNG_PACK
- * 17) PNG_BGR
- * 18) PNG_PACKSWAP
- * 19) PNG_FILLER (includes PNG_ADD_ALPHA)
- * 20) PNG_INVERT_ALPHA
- * 21) PNG_SWAP_ALPHA
- * 22) PNG_SWAP_BYTES
- * 23) PNG_USER_TRANSFORM [must be last]
- */
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
- if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
- !(png_ptr->transformations & PNG_COMPOSE))
- {
- /* Stripping the alpha channel happens immediately after the 'expand'
- * transformations, before all other transformation, so it cancels out
- * the alpha handling. It has the side effect negating the effect of
- * PNG_EXPAND_tRNS too:
- */
- png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
- PNG_EXPAND_tRNS);
- png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-
- /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen
- * so transparency information would remain just so long as it wasn't
- * expanded. This produces unexpected API changes if the set of things
- * that do PNG_EXPAND_tRNS changes (perfectly possible given the
- * documentation - which says ask for what you want, accept what you
- * get.) This makes the behavior consistent from 1.5.4:
- */
- png_ptr->num_trans = 0;
- }
-#endif /* STRIP_ALPHA supported, no COMPOSE */
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
- * settings will have no effect.
- */
- if (!png_gamma_significant(png_ptr->screen_gamma))
- {
- png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
- png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
- }
-#endif
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
- /* Make sure the coefficients for the rgb to gray conversion are set
- * appropriately.
- */
- if (png_ptr->transformations & PNG_RGB_TO_GRAY)
- png_colorspace_set_rgb_coefficients(png_ptr);
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_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.
- *
- * TODO: this code needs to be revised to avoid the complexity and
- * interdependencies. The color type of the background should be recorded in
- * png_set_background, along with the bit depth, then the code has a record
- * of exactly what color space the background is currently in.
- */
- if (png_ptr->transformations & PNG_BACKGROUND_EXPAND)
- {
- /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
- * the file was grayscale the background value is gray.
- */
- if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
- png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
- }
-
- else if (png_ptr->transformations & PNG_COMPOSE)
- {
- /* PNG_COMPOSE: png_set_background was called with need_expand false,
- * so the color is in the color space of the output or png_set_alpha_mode
- * was called and the color is black. Ignore RGB_TO_GRAY because that
- * happens before GRAY_TO_RGB.
- */
- if (png_ptr->transformations & PNG_GRAY_TO_RGB)
- {
- if (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 /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
-#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
-
- /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
- * can be performed directly on the palette, and some (such as rgb to gray)
- * can be optimized inside the palette. This is particularly true of the
- * composite (background and alpha) stuff, which can be pretty much all done
- * in the palette even if the result is expanded to RGB or gray afterward.
- *
- * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
- * earlier and the palette stuff is actually handled on the first row. This
- * leads to the reported bug that the palette returned by png_get_PLTE is not
- * updated.
- */
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
- png_init_palette_transformations(png_ptr);
-
- else
- png_init_rgb_transformations(png_ptr);
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
- defined(PNG_READ_EXPAND_16_SUPPORTED)
- if ((png_ptr->transformations & PNG_EXPAND_16) &&
- (png_ptr->transformations & PNG_COMPOSE) &&
- !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
- png_ptr->bit_depth != 16)
- {
- /* TODO: fix this. Because the expand_16 operation is after the compose
- * handling the background color must be 8, not 16, bits deep, but the
- * application will supply a 16-bit value so reduce it here.
- *
- * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
- * present, so that case is ok (until do_expand_16 is moved.)
- *
- * NOTE: this discards the low 16 bits of the user supplied background
- * color, but until expand_16 works properly there is no choice!
- */
-# define CHOP(x) (x)=((png_uint_16)PNG_DIV257(x))
- CHOP(png_ptr->background.red);
- CHOP(png_ptr->background.green);
- CHOP(png_ptr->background.blue);
- CHOP(png_ptr->background.gray);
-# undef CHOP
- }
-#endif /* PNG_READ_BACKGROUND_SUPPORTED && PNG_READ_EXPAND_16_SUPPORTED */
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
- (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
- defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
- if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) &&
- (png_ptr->transformations & PNG_COMPOSE) &&
- !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
- png_ptr->bit_depth == 16)
- {
- /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
- * component this will also happen after PNG_COMPOSE and so the background
- * color must be pre-expanded here.
- *
- * TODO: fix this too.
- */
- png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
- png_ptr->background.green =
- (png_uint_16)(png_ptr->background.green * 257);
- png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
- png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
- }
-#endif
-
- /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
- * background support (see the comments in scripts/pnglibconf.dfa), this
- * allows pre-multiplication of the alpha channel to be implemented as
- * compositing on black. This is probably sub-optimal and has been done in
- * 1.5.4 betas simply to enable external critique and testing (i.e. to
- * implement the new API quickly, without lots of internal changes.)
- */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-# ifdef PNG_READ_BACKGROUND_SUPPORTED
- /* Includes ALPHA_MODE */
- png_ptr->background_1 = png_ptr->background;
-# endif
-
- /* This needs to change - in the palette image case a whole set of tables are
- * built when it would be quicker to just calculate the correct value for
- * each palette entry directly. Also, the test is too tricky - why check
- * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that
- * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the
- * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
- * the gamma tables will not be built even if composition is required on a
- * gamma encoded value.
- *
- * In 1.5.4 this is addressed below by an additional check on the individual
- * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
- * tables.
- */
- if ((png_ptr->transformations & PNG_GAMMA)
- || ((png_ptr->transformations & PNG_RGB_TO_GRAY)
- && (png_gamma_significant(png_ptr->colorspace.gamma) ||
- png_gamma_significant(png_ptr->screen_gamma)))
- || ((png_ptr->transformations & PNG_COMPOSE)
- && (png_gamma_significant(png_ptr->colorspace.gamma)
- || png_gamma_significant(png_ptr->screen_gamma)
-# ifdef PNG_READ_BACKGROUND_SUPPORTED
- || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE
- && png_gamma_significant(png_ptr->background_gamma))
-# endif
- )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA)
- && png_gamma_significant(png_ptr->screen_gamma))
- )
- {
- png_build_gamma_table(png_ptr, png_ptr->bit_depth);
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- if (png_ptr->transformations & PNG_COMPOSE)
- {
- /* Issue a warning about this combination: because RGB_TO_GRAY is
- * optimized to do the gamma transform if present yet do_background has
- * to do the same thing if both options are set a
- * double-gamma-correction happens. This is true in all versions of
- * libpng to date.
- */
- if (png_ptr->transformations & PNG_RGB_TO_GRAY)
- png_warning(png_ptr,
- "libpng does not support gamma+background+rgb_to_gray");
-
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
- {
- /* We don't get to here unless there is a tRNS chunk with non-opaque
- * entries - see the checking code at the start of this function.
- */
- 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
- {
- png_fixed_point g, gs;
-
- switch (png_ptr->background_gamma_type)
- {
- case PNG_BACKGROUND_GAMMA_SCREEN:
- g = (png_ptr->screen_gamma);
- gs = PNG_FP_1;
- break;
-
- case PNG_BACKGROUND_GAMMA_FILE:
- g = png_reciprocal(png_ptr->colorspace.gamma);
- gs = png_reciprocal2(png_ptr->colorspace.gamma,
- png_ptr->screen_gamma);
- break;
-
- case PNG_BACKGROUND_GAMMA_UNIQUE:
- g = png_reciprocal(png_ptr->background_gamma);
- gs = png_reciprocal2(png_ptr->background_gamma,
- png_ptr->screen_gamma);
- break;
- default:
- g = PNG_FP_1; /* back_1 */
- gs = PNG_FP_1; /* back */
- break;
- }
-
- if (png_gamma_significant(gs))
- {
- back.red = png_gamma_8bit_correct(png_ptr->background.red,
- gs);
- back.green = png_gamma_8bit_correct(png_ptr->background.green,
- gs);
- back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
- gs);
- }
-
- else
- {
- back.red = (png_byte)png_ptr->background.red;
- back.green = (png_byte)png_ptr->background.green;
- back.blue = (png_byte)png_ptr->background.blue;
- }
-
- if (png_gamma_significant(g))
- {
- back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
- g);
- back_1.green = png_gamma_8bit_correct(
- png_ptr->background.green, g);
- back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
- g);
- }
-
- else
- {
- back_1.red = (png_byte)png_ptr->background.red;
- back_1.green = (png_byte)png_ptr->background.green;
- back_1.blue = (png_byte)png_ptr->background.blue;
- }
- }
-
- for (i = 0; i < num_palette; i++)
- {
- if (i < (int)png_ptr->num_trans &&
- png_ptr->trans_alpha[i] != 0xff)
- {
- if (png_ptr->trans_alpha[i] == 0)
- {
- palette[i] = back;
- }
- else /* if (png_ptr->trans_alpha[i] != 0xff) */
- {
- png_byte v, w;
-
- v = png_ptr->gamma_to_1[palette[i].red];
- png_composite(w, v, png_ptr->trans_alpha[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_alpha[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_alpha[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.
- *
- * NOTE: this is highly dubious; it removes the transformations in
- * place. This seems inconsistent with the general treatment of the
- * transformations elsewhere.
- */
- png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
- } /* color_type == PNG_COLOR_TYPE_PALETTE */
-
- /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
- else /* color_type != PNG_COLOR_TYPE_PALETTE */
- {
- int gs_sig, g_sig;
- png_fixed_point g = PNG_FP_1; /* Correction to linear */
- png_fixed_point gs = PNG_FP_1; /* Correction to screen */
-
- switch (png_ptr->background_gamma_type)
- {
- case PNG_BACKGROUND_GAMMA_SCREEN:
- g = png_ptr->screen_gamma;
- /* gs = PNG_FP_1; */
- break;
-
- case PNG_BACKGROUND_GAMMA_FILE:
- g = png_reciprocal(png_ptr->colorspace.gamma);
- gs = png_reciprocal2(png_ptr->colorspace.gamma,
- png_ptr->screen_gamma);
- break;
-
- case PNG_BACKGROUND_GAMMA_UNIQUE:
- g = png_reciprocal(png_ptr->background_gamma);
- gs = png_reciprocal2(png_ptr->background_gamma,
- png_ptr->screen_gamma);
- break;
-
- default:
- png_error(png_ptr, "invalid background gamma type");
- }
-
- g_sig = png_gamma_significant(g);
- gs_sig = png_gamma_significant(gs);
-
- if (g_sig)
- png_ptr->background_1.gray = png_gamma_correct(png_ptr,
- png_ptr->background.gray, g);
-
- if (gs_sig)
- png_ptr->background.gray = png_gamma_correct(png_ptr,
- png_ptr->background.gray, gs);
-
- 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 */
- if (g_sig)
- {
- png_ptr->background_1.red = png_gamma_correct(png_ptr,
- png_ptr->background.red, g);
-
- png_ptr->background_1.green = png_gamma_correct(png_ptr,
- png_ptr->background.green, g);
-
- png_ptr->background_1.blue = png_gamma_correct(png_ptr,
- png_ptr->background.blue, g);
- }
-
- if (gs_sig)
- {
- png_ptr->background.red = png_gamma_correct(png_ptr,
- png_ptr->background.red, gs);
-
- png_ptr->background.green = png_gamma_correct(png_ptr,
- png_ptr->background.green, gs);
-
- png_ptr->background.blue = png_gamma_correct(png_ptr,
- png_ptr->background.blue, gs);
- }
- }
-
- 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;
- }
-
- /* The background is now in screen gamma: */
- png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
- } /* color_type != PNG_COLOR_TYPE_PALETTE */
- }/* png_ptr->transformations & PNG_BACKGROUND */
-
- else
- /* Transformation does not include PNG_BACKGROUND */
-#endif /* PNG_READ_BACKGROUND_SUPPORTED */
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
- /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
- && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
- (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
-#endif
- )
- {
- png_colorp palette = png_ptr->palette;
- int num_palette = png_ptr->num_palette;
- int i;
-
- /* NOTE: there are other transformations that should probably be in
- * here too.
- */
- 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;
- } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
- }
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- else
-#endif
-#endif /* PNG_READ_GAMMA_SUPPORTED */
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- /* No GAMMA transformation (see the hanging else 4 lines above) */
- if ((png_ptr->transformations & PNG_COMPOSE) &&
- (png_ptr->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_alpha[i] == 0)
- {
- palette[i] = back;
- }
-
- else if (png_ptr->trans_alpha[i] != 0xff)
- {
- /* The png_composite() macro is defined in png.h */
- png_composite(palette[i].red, palette[i].red,
- png_ptr->trans_alpha[i], back.red);
-
- png_composite(palette[i].green, palette[i].green,
- png_ptr->trans_alpha[i], back.green);
-
- png_composite(palette[i].blue, palette[i].blue,
- png_ptr->trans_alpha[i], back.blue);
- }
- }
-
- png_ptr->transformations &= ~PNG_COMPOSE;
-
- //png_ptr->flags |= PNG_FLAG_STRIP_ALPHA; /* Add by Sunliang.Liu */
- }
-#endif /* PNG_READ_BACKGROUND_SUPPORTED */
-
-#ifdef PNG_READ_SHIFT_SUPPORTED
- if ((png_ptr->transformations & PNG_SHIFT) &&
- !(png_ptr->transformations & PNG_EXPAND) &&
- (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
- {
- int i;
- int istop = png_ptr->num_palette;
- int shift = 8 - png_ptr->sig_bit.red;
-
- png_ptr->transformations &= ~PNG_SHIFT;
-
- /* significant bits can be in the range 1 to 7 for a meaninful result, if
- * the number of significant bits is 0 then no shift is done (this is an
- * error condition which is silently ignored.)
- */
- if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
- {
- int component = png_ptr->palette[i].red;
-
- component >>= shift;
- png_ptr->palette[i].red = (png_byte)component;
- }
-
- shift = 8 - png_ptr->sig_bit.green;
- if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
- {
- int component = png_ptr->palette[i].green;
-
- component >>= shift;
- png_ptr->palette[i].green = (png_byte)component;
- }
-
- shift = 8 - png_ptr->sig_bit.blue;
- if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
- {
- int component = png_ptr->palette[i].blue;
-
- component >>= shift;
- png_ptr->palette[i].blue = (png_byte)component;
- }
- }
-#endif /* PNG_READ_SHIFT_SUPPORTED */
-}
-
-/* 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_structrp png_ptr, png_inforp 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)
- {
- /* This check must match what actually happens in
- * png_do_expand_palette; if it ever checks the tRNS chunk to see if
- * it is all opaque we must do the same (at present it does not.)
- */
- if (png_ptr->num_trans > 0)
- 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
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
- defined(PNG_READ_ALPHA_MODE_SUPPORTED)
- /* The following is almost certainly wrong unless the background value is in
- * the screen space!
- */
- if (png_ptr->transformations & PNG_COMPOSE)
- info_ptr->background = png_ptr->background;
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
- /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
- * however it seems that the code in png_init_read_transformations, which has
- * been called before this from png_read_update_info->png_read_start_row
- * sometimes does the gamma transform and cancels the flag.
- *
- * TODO: this looks wrong; the info_ptr should end up with a gamma equal to
- * the screen_gamma value. The following probably results in weirdness if
- * the info_ptr is used by the app after the rows have been read.
- */
- info_ptr->colorspace.gamma = png_ptr->colorspace.gamma;
-#endif
-
- if (info_ptr->bit_depth == 16)
- {
-# ifdef PNG_READ_16BIT_SUPPORTED
-# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
- if (png_ptr->transformations & PNG_SCALE_16_TO_8)
- info_ptr->bit_depth = 8;
-# endif
-
-# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
- if (png_ptr->transformations & PNG_16_TO_8)
- info_ptr->bit_depth = 8;
-# endif
-
-# else
- /* No 16 bit support: force chopping 16-bit input down to 8, in this case
- * the app program can chose if both APIs are available by setting the
- * correct scaling to use.
- */
-# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
- /* For compatibility with previous versions use the strip method by
- * default. This code works because if PNG_SCALE_16_TO_8 is already
- * set the code below will do that in preference to the chop.
- */
- png_ptr->transformations |= PNG_16_TO_8;
- info_ptr->bit_depth = 8;
-# else
-
-# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
- png_ptr->transformations |= PNG_SCALE_16_TO_8;
- info_ptr->bit_depth = 8;
-# else
-
- CONFIGURATION ERROR: you must enable at least one 16 to 8 method
-# endif
-# endif
-#endif /* !READ_16BIT_SUPPORTED */
- }
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
- if (png_ptr->transformations & PNG_GRAY_TO_RGB)
- info_ptr->color_type = (png_byte)(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_byte)(info_ptr->color_type &
- ~PNG_COLOR_MASK_COLOR);
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
- if (png_ptr->transformations & PNG_QUANTIZE)
- {
- 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_EXPAND_16_SUPPORTED
- if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 &&
- info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
- {
- info_ptr->bit_depth = 16;
- }
-#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->transformations & PNG_STRIP_ALPHA)
- {
- info_ptr->color_type = (png_byte)(info_ptr->color_type &
- ~PNG_COLOR_MASK_ALPHA);
- info_ptr->num_trans = 0;
- }
-#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 */
- if (png_ptr->transformations & PNG_ADD_ALPHA)
- info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
- }
-#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);
-
- /* Adding in 1.5.4: cache the above value in png_struct so that we can later
- * check in png_rowbytes that the user buffer won't get overwritten. Note
- * that the field is not always set - if png_read_update_info isn't called
- * the application has to either not do any transforms or get the calculation
- * right itself.
- */
- png_ptr->info_rowbytes = info_ptr->rowbytes;
-
-#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_structrp png_ptr, png_row_infop row_info)
-{
- png_debug(1, "in png_do_read_transformations");
-
- if (png_ptr->row_buf == NULL)
- {
- /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
- * error is incredibly rare and incredibly easy to debug without this
- * information.
- */
- png_error(png_ptr, "NULL row buffer");
- }
-
- /* The following is debugging; prior to 1.5.4 the code was never compiled in;
- * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
- * PNG_WARN_UNINITIALIZED_ROW removed. In 1.6 the new flag is set only for
- * all transformations, however in practice the ROW_INIT always gets done on
- * demand, if necessary.
- */
- if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
- !(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 (but not enabled until 1.5.4).
- */
- png_error(png_ptr, "Uninitialized row");
- }
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
- if (png_ptr->transformations & PNG_EXPAND)
- {
- if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
- {
- png_do_expand_palette(row_info, png_ptr->row_buf + 1,
- png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
- }
-
- else
- {
- if (png_ptr->num_trans &&
- (png_ptr->transformations & PNG_EXPAND_tRNS))
- png_do_expand(row_info, png_ptr->row_buf + 1,
- &(png_ptr->trans_color));
-
- else
- png_do_expand(row_info, png_ptr->row_buf + 1,
- NULL);
- }
- }
-#endif
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
- if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
- !(png_ptr->transformations & PNG_COMPOSE) &&
- (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
- row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
- png_do_strip_channel(row_info, png_ptr->row_buf + 1,
- 0 /* at_start == false, because SWAP_ALPHA happens later */);
-#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, 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(row_info, png_ptr->row_buf + 1);
-#endif
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
- defined(PNG_READ_ALPHA_MODE_SUPPORTED)
- if (png_ptr->transformations & PNG_COMPOSE)
- png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if ((png_ptr->transformations & PNG_GAMMA) &&
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
- /* Because RGB_TO_GRAY does the gamma transform. */
- !(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
-#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
- defined(PNG_READ_ALPHA_MODE_SUPPORTED)
- /* Because PNG_COMPOSE does the gamma transform if there is something to
- * do (if there is an alpha channel or transparency.)
- */
- !((png_ptr->transformations & PNG_COMPOSE) &&
- ((png_ptr->num_trans != 0) ||
- (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
-#endif
- /* Because png_init_read_transformations transforms the palette, unless
- * RGB_TO_GRAY will do the transform.
- */
- (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
- png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
-#endif
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
- if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
- (png_ptr->transformations & PNG_COMPOSE) &&
- (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
- row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
- png_do_strip_channel(row_info, png_ptr->row_buf + 1,
- 0 /* at_start == false, because SWAP_ALPHA happens later */);
-#endif
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
- (row_info->color_type & PNG_COLOR_MASK_ALPHA))
- png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
-#endif
-
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
- if (png_ptr->transformations & PNG_SCALE_16_TO_8)
- png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
- /* There is no harm in doing both of these because only one has any effect,
- * by putting the 'scale' option first if the app asks for scale (either by
- * calling the API or in a TRANSFORM flag) this is what happens.
- */
- if (png_ptr->transformations & PNG_16_TO_8)
- png_do_chop(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
- if (png_ptr->transformations & PNG_QUANTIZE)
- {
- png_do_quantize(row_info, png_ptr->row_buf + 1,
- png_ptr->palette_lookup, png_ptr->quantize_index);
-
- if (row_info->rowbytes == 0)
- png_error(png_ptr, "png_do_quantize returned rowbytes=0");
- }
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
- /* Do the expansion now, after all the arithmetic has been done. Notice
- * that previous transformations can handle the PNG_EXPAND_16 flag if this
- * is efficient (particularly true in the case of gamma correction, where
- * better accuracy results faster!)
- */
- if (png_ptr->transformations & PNG_EXPAND_16)
- png_do_expand_16(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
- /* NOTE: moved here in 1.5.4 (from much later in this list.) */
- if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
- (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
- png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_INVERT_SUPPORTED
- if (png_ptr->transformations & PNG_INVERT_MONO)
- png_do_invert(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_SHIFT_SUPPORTED
- if (png_ptr->transformations & PNG_SHIFT)
- png_do_unshift(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(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
- /* Added at libpng-1.5.10 */
- if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
- png_ptr->num_palette_max >= 0)
- png_do_check_palette_indexes(png_ptr, row_info);
-#endif
-
-#ifdef PNG_READ_BGR_SUPPORTED
- if (png_ptr->transformations & PNG_BGR)
- png_do_bgr(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_PACKSWAP_SUPPORTED
- if (png_ptr->transformations & PNG_PACKSWAP)
- png_do_packswap(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_FILLER_SUPPORTED
- if (png_ptr->transformations & PNG_FILLER)
- png_do_read_filler(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(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(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-#ifdef PNG_READ_SWAP_SUPPORTED
- if (png_ptr->transformations & PNG_SWAP_BYTES)
- png_do_swap(row_info, png_ptr->row_buf + 1);
-#endif
-#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 */
- row_info, /* row_info: */
- /* png_uint_32 width; width of row */
- /* png_size_t 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)
- row_info->bit_depth = png_ptr->user_transform_depth;
-
- if (png_ptr->user_transform_channels)
- row_info->channels = png_ptr->user_transform_channels;
-#endif
- row_info->pixel_depth = (png_byte)(row_info->bit_depth *
- row_info->channels);
-
- row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, 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");
-
- if (row_info->bit_depth < 8)
- {
- 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;
- }
-
- default:
- 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_const_color_8p sig_bits)
-{
- int color_type;
-
- png_debug(1, "in png_do_unshift");
-
- /* The palette case has already been handled in the _init routine. */
- color_type = row_info->color_type;
-
- if (color_type != PNG_COLOR_TYPE_PALETTE)
- {
- int shift[4];
- int channels = 0;
- int bit_depth = row_info->bit_depth;
-
- if (color_type & PNG_COLOR_MASK_COLOR)
- {
- shift[channels++] = bit_depth - sig_bits->red;
- shift[channels++] = bit_depth - sig_bits->green;
- shift[channels++] = bit_depth - sig_bits->blue;
- }
-
- else
- {
- shift[channels++] = bit_depth - sig_bits->gray;
- }
-
- if (color_type & PNG_COLOR_MASK_ALPHA)
- {
- shift[channels++] = bit_depth - sig_bits->alpha;
- }
-
- {
- int c, have_shift;
-
- for (c = have_shift = 0; c < channels; ++c)
- {
- /* A shift of more than the bit depth is an error condition but it
- * gets ignored here.
- */
- if (shift[c] <= 0 || shift[c] >= bit_depth)
- shift[c] = 0;
-
- else
- have_shift = 1;
- }
-
- if (!have_shift)
- return;
- }
-
- switch (bit_depth)
- {
- default:
- /* Must be 1bpp gray: should not be here! */
- /* NOTREACHED */
- break;
-
- case 2:
- /* Must be 2bpp gray */
- /* assert(channels == 1 && shift[0] == 1) */
- {
- png_bytep bp = row;
- png_bytep bp_end = bp + row_info->rowbytes;
-
- while (bp < bp_end)
- {
- int b = (*bp >> 1) & 0x55;
- *bp++ = (png_byte)b;
- }
- break;
- }
-
- case 4:
- /* Must be 4bpp gray */
- /* assert(channels == 1) */
- {
- png_bytep bp = row;
- png_bytep bp_end = bp + row_info->rowbytes;
- int gray_shift = shift[0];
- int mask = 0xf >> gray_shift;
-
- mask |= mask << 4;
-
- while (bp < bp_end)
- {
- int b = (*bp >> gray_shift) & mask;
- *bp++ = (png_byte)b;
- }
- break;
- }
-
- case 8:
- /* Single byte components, G, GA, RGB, RGBA */
- {
- png_bytep bp = row;
- png_bytep bp_end = bp + row_info->rowbytes;
- int channel = 0;
-
- while (bp < bp_end)
- {
- int b = *bp >> shift[channel];
- if (++channel >= channels)
- channel = 0;
- *bp++ = (png_byte)b;
- }
- break;
- }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
- case 16:
- /* Double byte components, G, GA, RGB, RGBA */
- {
- png_bytep bp = row;
- png_bytep bp_end = bp + row_info->rowbytes;
- int channel = 0;
-
- while (bp < bp_end)
- {
- int value = (bp[0] << 8) + bp[1];
-
- value >>= shift[channel];
- if (++channel >= channels)
- channel = 0;
- *bp++ = (png_byte)(value >> 8);
- *bp++ = (png_byte)(value & 0xff);
- }
- break;
- }
-#endif
- }
- }
-}
-#endif
-
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-/* Scale rows of bit depth 16 down to 8 accurately */
-void /* PRIVATE */
-png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
-{
- png_debug(1, "in png_do_scale_16_to_8");
-
- if (row_info->bit_depth == 16)
- {
- png_bytep sp = row; /* source */
- png_bytep dp = row; /* destination */
- png_bytep ep = sp + row_info->rowbytes; /* end+1 */
-
- while (sp < ep)
- {
- /* The input is an array of 16 bit components, these must be scaled to
- * 8 bits each. For a 16 bit value V the required value (from the PNG
- * specification) is:
- *
- * (V * 255) / 65535
- *
- * This reduces to round(V / 257), or floor((V + 128.5)/257)
- *
- * Represent V as the two byte value vhi.vlo. Make a guess that the
- * result is the top byte of V, vhi, then the correction to this value
- * is:
- *
- * error = floor(((V-vhi.vhi) + 128.5) / 257)
- * = floor(((vlo-vhi) + 128.5) / 257)
- *
- * This can be approximated using integer arithmetic (and a signed
- * shift):
- *
- * error = (vlo-vhi+128) >> 8;
- *
- * The approximate differs from the exact answer only when (vlo-vhi) is
- * 128; it then gives a correction of +1 when the exact correction is
- * 0. This gives 128 errors. The exact answer (correct for all 16 bit
- * input values) is:
- *
- * error = (vlo-vhi+128)*65535 >> 24;
- *
- * An alternative arithmetic calculation which also gives no errors is:
- *
- * (V * 255 + 32895) >> 16
- */
-
- png_int_32 tmp = *sp++; /* must be signed! */
- tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
- *dp++ = (png_byte)tmp;
- }
-
- 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_STRIP_16_TO_8_SUPPORTED
-void /* PRIVATE */
-/* Simply discard the low byte. This was the default behavior prior
- * to libpng-1.5.4.
- */
-png_do_chop(png_row_infop row_info, png_bytep row)
-{
- png_debug(1, "in png_do_chop");
-
- if (row_info->bit_depth == 16)
- {
- png_bytep sp = row; /* source */
- png_bytep dp = row; /* destination */
- png_bytep ep = sp + row_info->rowbytes; /* end+1 */
-
- while (sp < ep)
- {
- *dp++ = *sp;
- sp += 2; /* skip low byte */
- }
-
- 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");
-
- {
- 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;
- }
- }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
- /* 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];
- }
- }
-#endif
- }
-
- 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;
- }
- }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
- /* 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
- }
- }
-}
-#endif
-
-#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-void /* PRIVATE */
-png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
-{
- png_uint_32 row_width;
- png_debug(1, "in png_do_read_invert_alpha");
-
- row_width = row_info->width;
- if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
- {
- if (row_info->bit_depth == 8)
- {
- /* This inverts the alpha channel in RGBA */
- 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;
- }
- }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
- /* 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;
- }
- }
-#endif
- }
- else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
- {
- if (row_info->bit_depth == 8)
- {
- /* This inverts the alpha channel in GA */
- 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);
- }
- }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
- else
- {
- /* This inverts the alpha channel in GGAA */
- 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
- }
-}
-#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;
-
-#ifdef PNG_READ_16BIT_SUPPORTED
- png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
-#endif
- png_byte lo_filler = (png_byte)(filler & 0xff);
-
- png_debug(1, "in png_do_read_filler");
-
- if (
- row_info->color_type == PNG_COLOR_TYPE_GRAY)
- {
- if (row_info->bit_depth == 8)
- {
- if (flags & PNG_FLAG_FILLER_AFTER)
- {
- /* This changes the data from G to GX */
- 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;
- }
-
- else
- {
- /* This changes the data from G to XG */
- 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;
- }
- }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
- else if (row_info->bit_depth == 16)
- {
- if (flags & PNG_FLAG_FILLER_AFTER)
- {
- /* This changes the data from GG to GGXX */
- 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;
- }
-
- else
- {
- /* This changes the data from GG to XXGG */
- 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;
- }
- }
-#endif
- } /* COLOR_TYPE == GRAY */
- else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
- {
- if (row_info->bit_depth == 8)
- {
- if (flags & PNG_FLAG_FILLER_AFTER)
- {
- /* This changes the data from RGB to RGBX */
- 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;
- }
-
- else
- {
- /* This changes the data from RGB to XRGB */
- 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;
- }
- }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
- else if (row_info->bit_depth == 16)
- {
- if (flags & PNG_FLAG_FILLER_AFTER)
- {
- /* This changes the data from RRGGBB to RRGGBBXX */
- 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;
- }
-
- else
- {
- /* This changes the data from RRGGBB to XXRRGGBB */
- 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;
- }
- }
-#endif
- } /* 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 &&
- !(row_info->color_type & PNG_COLOR_MASK_COLOR))
- {
- if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
- {
- if (row_info->bit_depth == 8)
- {
- /* This changes G to RGB */
- 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
- {
- /* This changes GG to RRGGBB */
- 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)
- {
- /* This changes GA to RGBA */
- 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
- {
- /* This changes GGAA to RRGGBBAA */
- 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)(row_info->channels + 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 of 1998-01-04 at
- * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008 but
- * versions dated 1998 through November 2002 have been archived at
- * http://web.archive.org/web/20000816232553/http://www.inforamp.net/
- * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
- * Charles Poynton poynton at poynton.com
- *
- * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
- *
- * which can be expressed with integers as
- *
- * Y = (6969 * R + 23434 * G + 2365 * B)/32768
- *
- * Poynton's current link (as of January 2003 through July 2011):
- * <http://www.poynton.com/notes/colour_and_gamma/>
- * has changed the numbers slightly:
- *
- * Y = 0.2126*R + 0.7152*G + 0.0722*B
- *
- * which can be expressed with integers as
- *
- * Y = (6966 * R + 23436 * G + 2366 * B)/32768
- *
- * Historically, however, libpng uses numbers derived from the ITU-R Rec 709
- * end point chromaticities and the D65 white point. Depending on the
- * precision used for the D65 white point this produces a variety of different
- * numbers, however if the four decimal place value used in ITU-R Rec 709 is
- * used (0.3127,0.3290) the Y calculation would be:
- *
- * Y = (6968 * R + 23435 * G + 2366 * B)/32768
- *
- * While this is correct the rounding results in an overflow for white, because
- * the sum of the rounded coefficients is 32769, not 32768. Consequently
- * libpng uses, instead, the closest non-overflowing approximation:
- *
- * Y = (6968 * R + 23434 * G + 2366 * B)/32768
- *
- * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
- * (including an sRGB chunk) then the chromaticities are used to calculate the
- * coefficients. See the chunk handling in pngrutil.c for more information.
- *
- * In all cases the calculation is to be done in a linear colorspace. If no
- * gamma information is available to correct the encoding of the original RGB
- * values this results in an implicit assumption that the original PNG RGB
- * values were linear.
- *
- * Other integer coefficents can be used via png_set_rgb_to_gray(). Because
- * the API takes just red and green coefficients the blue coefficient is
- * calculated to make the sum 32768. This will result in different rounding
- * to that used above.
- */
-int /* PRIVATE */
-png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
-
-{
- int rgb_error = 0;
-
- png_debug(1, "in png_do_rgb_to_gray");
-
- if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) &&
- (row_info->color_type & PNG_COLOR_MASK_COLOR))
- {
- PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
- PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
- PNG_CONST png_uint_32 bc = 32768 - rc - gc;
- PNG_CONST png_uint_32 row_width = row_info->width;
- PNG_CONST int have_alpha =
- (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
-
- if (row_info->bit_depth == 8)
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- /* Notice that gamma to/from 1 are not necessarily inverses (if
- * there is an overall gamma correction). Prior to 1.5.5 this code
- * checked the linearized values for equality; this doesn't match
- * the documentation, the original values must be checked.
- */
- if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
- {
- png_bytep sp = row;
- png_bytep dp = row;
- png_uint_32 i;
-
- for (i = 0; i < row_width; i++)
- {
- png_byte red = *(sp++);
- png_byte green = *(sp++);
- png_byte blue = *(sp++);
-
- if (red != green || red != blue)
- {
- red = png_ptr->gamma_to_1[red];
- green = png_ptr->gamma_to_1[green];
- blue = png_ptr->gamma_to_1[blue];
-
- rgb_error |= 1;
- *(dp++) = png_ptr->gamma_from_1[
- (rc*red + gc*green + bc*blue + 16384)>>15];
- }
-
- else
- {
- /* If there is no overall correction the table will not be
- * set.
- */
- if (png_ptr->gamma_table != NULL)
- red = png_ptr->gamma_table[red];
-
- *(dp++) = red;
- }
-
- if (have_alpha)
- *(dp++) = *(sp++);
- }
- }
- else
-#endif
- {
- png_bytep sp = row;
- png_bytep dp = row;
- png_uint_32 i;
-
- 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;
- /* NOTE: this is the historical approach which simply
- * truncates the results.
- */
- *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
- }
-
- else
- *(dp++) = red;
-
- if (have_alpha)
- *(dp++) = *(sp++);
- }
- }
- }
-
- else /* RGB bit_depth == 16 */
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
- {
- png_bytep sp = row;
- png_bytep dp = row;
- png_uint_32 i;
-
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 red, green, blue, w;
-
- red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-
- if (red == green && red == blue)
- {
- if (png_ptr->gamma_16_table != NULL)
- w = png_ptr->gamma_16_table[(red&0xff)
- >> png_ptr->gamma_shift][red>>8];
-
- else
- 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 + 16384)>>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);
-
- if (have_alpha)
- {
- *(dp++) = *(sp++);
- *(dp++) = *(sp++);
- }
- }
- }
- else
-#endif
- {
- png_bytep sp = row;
- png_bytep dp = row;
- png_uint_32 i;
-
- 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;
-
- /* From 1.5.5 in the 16 bit case do the accurate conversion even
- * in the 'fast' case - this is because this is where the code
- * ends up when handling linear 16 bit data.
- */
- gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
- 15);
- *(dp++) = (png_byte)((gray16>>8) & 0xff);
- *(dp++) = (png_byte)(gray16 & 0xff);
-
- if (have_alpha)
- {
- *(dp++) = *(sp++);
- *(dp++) = *(sp++);
- }
- }
- }
- }
-
- row_info->channels = (png_byte)(row_info->channels - 2);
- row_info->color_type = (png_byte)(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
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
-/* 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. This API is not used internally.
- */
-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;
- }
-}
-#endif
-
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
- defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-/* Replace any alpha or transparency with the supplied background color.
- * "background" is already in the screen gamma, while "background_1" is
- * at a gamma of 1.0. Paletted files have already been taken care of.
- */
-void /* PRIVATE */
-png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
-{
-#ifdef PNG_READ_GAMMA_SUPPORTED
- png_const_bytep gamma_table = png_ptr->gamma_table;
- png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
- png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
- png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
- png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
- png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
- int gamma_shift = png_ptr->gamma_shift;
- int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
-#endif
-
- png_bytep sp;
- png_uint_32 i;
- png_uint_32 row_width = row_info->width;
- int shift;
-
- png_debug(1, "in png_do_compose");
-
- {
- switch (row_info->color_type)
- {
- case PNG_COLOR_TYPE_GRAY:
- {
- switch (row_info->bit_depth)
- {
- case 1:
- {
- sp = row;
- shift = 7;
- for (i = 0; i < row_width; i++)
- {
- if ((png_uint_16)((*sp >> shift) & 0x01)
- == png_ptr->trans_color.gray)
- {
- unsigned int tmp = *sp & (0x7f7f >> (7 - shift));
- tmp |= png_ptr->background.gray << shift;
- *sp = (png_byte)(tmp & 0xff);
- }
-
- if (!shift)
- {
- shift = 7;
- sp++;
- }
-
- else
- shift--;
- }
- break;
- }
-
- case 2:
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (gamma_table != NULL)
- {
- sp = row;
- shift = 6;
- for (i = 0; i < row_width; i++)
- {
- if ((png_uint_16)((*sp >> shift) & 0x03)
- == png_ptr->trans_color.gray)
- {
- unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
- tmp |= png_ptr->background.gray << shift;
- *sp = (png_byte)(tmp & 0xff);
- }
-
- else
- {
- unsigned int p = (*sp >> shift) & 0x03;
- unsigned int g = (gamma_table [p | (p << 2) |
- (p << 4) | (p << 6)] >> 6) & 0x03;
- unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
- tmp |= g << shift;
- *sp = (png_byte)(tmp & 0xff);
- }
-
- if (!shift)
- {
- shift = 6;
- sp++;
- }
-
- else
- shift -= 2;
- }
- }
-
- else
-#endif
- {
- sp = row;
- shift = 6;
- for (i = 0; i < row_width; i++)
- {
- if ((png_uint_16)((*sp >> shift) & 0x03)
- == png_ptr->trans_color.gray)
- {
- unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
- tmp |= png_ptr->background.gray << shift;
- *sp = (png_byte)(tmp & 0xff);
- }
-
- if (!shift)
- {
- shift = 6;
- sp++;
- }
-
- else
- shift -= 2;
- }
- }
- break;
- }
-
- case 4:
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (gamma_table != NULL)
- {
- sp = row;
- shift = 4;
- for (i = 0; i < row_width; i++)
- {
- if ((png_uint_16)((*sp >> shift) & 0x0f)
- == png_ptr->trans_color.gray)
- {
- unsigned int tmp = *sp & (0xf0f >> (4 - shift));
- tmp |= png_ptr->background.gray << shift;
- *sp = (png_byte)(tmp & 0xff);
- }
-
- else
- {
- unsigned int p = (*sp >> shift) & 0x0f;
- unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
- 0x0f;
- unsigned int tmp = *sp & (0xf0f >> (4 - shift));
- tmp |= g << shift;
- *sp = (png_byte)(tmp & 0xff);
- }
-
- if (!shift)
- {
- shift = 4;
- sp++;
- }
-
- else
- shift -= 4;
- }
- }
-
- else
-#endif
- {
- sp = row;
- shift = 4;
- for (i = 0; i < row_width; i++)
- {
- if ((png_uint_16)((*sp >> shift) & 0x0f)
- == png_ptr->trans_color.gray)
- {
- unsigned int tmp = *sp & (0xf0f >> (4 - shift));
- tmp |= png_ptr->background.gray << shift;
- *sp = (png_byte)(tmp & 0xff);
- }
-
- if (!shift)
- {
- shift = 4;
- sp++;
- }
-
- else
- shift -= 4;
- }
- }
- break;
- }
-
- case 8:
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (gamma_table != NULL)
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp++)
- {
- if (*sp == png_ptr->trans_color.gray)
- *sp = (png_byte)png_ptr->background.gray;
-
- else
- *sp = gamma_table[*sp];
- }
- }
- else
-#endif
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp++)
- {
- if (*sp == png_ptr->trans_color.gray)
- *sp = (png_byte)png_ptr->background.gray;
- }
- }
- break;
- }
-
- case 16:
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (gamma_16 != NULL)
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 2)
- {
- png_uint_16 v;
-
- v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
- if (v == png_ptr->trans_color.gray)
- {
- /* Background is already in screen gamma */
- *sp = (png_byte)((png_ptr->background.gray >> 8)
- & 0xff);
- *(sp + 1) = (png_byte)(png_ptr->background.gray
- & 0xff);
- }
-
- else
- {
- v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- }
- }
- }
- else
-#endif
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 2)
- {
- png_uint_16 v;
-
- v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
- if (v == png_ptr->trans_color.gray)
- {
- *sp = (png_byte)((png_ptr->background.gray >> 8)
- & 0xff);
- *(sp + 1) = (png_byte)(png_ptr->background.gray
- & 0xff);
- }
- }
- }
- break;
- }
-
- default:
- break;
- }
- break;
- }
-
- case PNG_COLOR_TYPE_RGB:
- {
- if (row_info->bit_depth == 8)
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (gamma_table != NULL)
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 3)
- {
- if (*sp == png_ptr->trans_color.red &&
- *(sp + 1) == png_ptr->trans_color.green &&
- *(sp + 2) == png_ptr->trans_color.blue)
- {
- *sp = (png_byte)png_ptr->background.red;
- *(sp + 1) = (png_byte)png_ptr->background.green;
- *(sp + 2) = (png_byte)png_ptr->background.blue;
- }
-
- else
- {
- *sp = gamma_table[*sp];
- *(sp + 1) = gamma_table[*(sp + 1)];
- *(sp + 2) = gamma_table[*(sp + 2)];
- }
- }
- }
- else
-#endif
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 3)
- {
- if (*sp == png_ptr->trans_color.red &&
- *(sp + 1) == png_ptr->trans_color.green &&
- *(sp + 2) == png_ptr->trans_color.blue)
- {
- *sp = (png_byte)png_ptr->background.red;
- *(sp + 1) = (png_byte)png_ptr->background.green;
- *(sp + 2) = (png_byte)png_ptr->background.blue;
- }
- }
- }
- }
- else /* if (row_info->bit_depth == 16) */
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (gamma_16 != NULL)
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 6)
- {
- png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
- png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
- + *(sp + 3));
-
- png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
- + *(sp + 5));
-
- if (r == png_ptr->trans_color.red &&
- g == png_ptr->trans_color.green &&
- b == png_ptr->trans_color.blue)
- {
- /* Background is already in screen gamma */
- *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
- *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
- *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
- & 0xff);
- *(sp + 3) = (png_byte)(png_ptr->background.green
- & 0xff);
- *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
- & 0xff);
- *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
- }
-
- else
- {
- png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
-
- v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
- *(sp + 2) = (png_byte)((v >> 8) & 0xff);
- *(sp + 3) = (png_byte)(v & 0xff);
-
- v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
- *(sp + 4) = (png_byte)((v >> 8) & 0xff);
- *(sp + 5) = (png_byte)(v & 0xff);
- }
- }
- }
-
- else
-#endif
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 6)
- {
- png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
- png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
- + *(sp + 3));
-
- png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
- + *(sp + 5));
-
- if (r == png_ptr->trans_color.red &&
- g == png_ptr->trans_color.green &&
- b == png_ptr->trans_color.blue)
- {
- *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
- *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
- *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
- & 0xff);
- *(sp + 3) = (png_byte)(png_ptr->background.green
- & 0xff);
- *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
- & 0xff);
- *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
- }
- }
- }
- }
- break;
- }
-
- case PNG_COLOR_TYPE_GRAY_ALPHA:
- {
- if (row_info->bit_depth == 8)
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
- gamma_table != NULL)
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 2)
- {
- png_uint_16 a = *(sp + 1);
-
- if (a == 0xff)
- *sp = gamma_table[*sp];
-
- else if (a == 0)
- {
- /* Background is already in screen gamma */
- *sp = (png_byte)png_ptr->background.gray;
- }
-
- else
- {
- png_byte v, w;
-
- v = gamma_to_1[*sp];
- png_composite(w, v, a, png_ptr->background_1.gray);
- if (!optimize)
- w = gamma_from_1[w];
- *sp = w;
- }
- }
- }
- else
-#endif
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 2)
- {
- png_byte a = *(sp + 1);
-
- if (a == 0)
- *sp = (png_byte)png_ptr->background.gray;
-
- else if (a < 0xff)
- png_composite(*sp, *sp, a, png_ptr->background.gray);
- }
- }
- }
- else /* if (png_ptr->bit_depth == 16) */
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
- gamma_16_to_1 != NULL)
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 4)
- {
- png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
- + *(sp + 3));
-
- if (a == (png_uint_16)0xffff)
- {
- png_uint_16 v;
-
- v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- }
-
- else if (a == 0)
- {
- /* Background is already in screen gamma */
- *sp = (png_byte)((png_ptr->background.gray >> 8)
- & 0xff);
- *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
- }
-
- else
- {
- png_uint_16 g, v, w;
-
- g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
- png_composite_16(v, g, a, png_ptr->background_1.gray);
- if (optimize)
- w = v;
- else
- w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
- *sp = (png_byte)((w >> 8) & 0xff);
- *(sp + 1) = (png_byte)(w & 0xff);
- }
- }
- }
- else
-#endif
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 4)
- {
- png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
- + *(sp + 3));
-
- if (a == 0)
- {
- *sp = (png_byte)((png_ptr->background.gray >> 8)
- & 0xff);
- *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
- }
-
- else if (a < 0xffff)
- {
- png_uint_16 g, v;
-
- g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
- png_composite_16(v, g, a, png_ptr->background.gray);
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- }
- }
- }
- }
- break;
- }
-
- case PNG_COLOR_TYPE_RGB_ALPHA:
- {
- if (row_info->bit_depth == 8)
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
- gamma_table != NULL)
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 4)
- {
- png_byte a = *(sp + 3);
-
- if (a == 0xff)
- {
- *sp = gamma_table[*sp];
- *(sp + 1) = gamma_table[*(sp + 1)];
- *(sp + 2) = gamma_table[*(sp + 2)];
- }
-
- else if (a == 0)
- {
- /* Background is already in screen gamma */
- *sp = (png_byte)png_ptr->background.red;
- *(sp + 1) = (png_byte)png_ptr->background.green;
- *(sp + 2) = (png_byte)png_ptr->background.blue;
- }
-
- else
- {
- png_byte v, w;
-
- v = gamma_to_1[*sp];
- png_composite(w, v, a, png_ptr->background_1.red);
- if (!optimize) w = gamma_from_1[w];
- *sp = w;
-
- v = gamma_to_1[*(sp + 1)];
- png_composite(w, v, a, png_ptr->background_1.green);
- if (!optimize) w = gamma_from_1[w];
- *(sp + 1) = w;
-
- v = gamma_to_1[*(sp + 2)];
- png_composite(w, v, a, png_ptr->background_1.blue);
- if (!optimize) w = gamma_from_1[w];
- *(sp + 2) = w;
- }
- }
- }
- else
-#endif
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 4)
- {
- png_byte a = *(sp + 3);
-
- if (a == 0)
- {
- *sp = (png_byte)png_ptr->background.red;
- *(sp + 1) = (png_byte)png_ptr->background.green;
- *(sp + 2) = (png_byte)png_ptr->background.blue;
- }
-
- else if (a < 0xff)
- {
- png_composite(*sp, *sp, a, png_ptr->background.red);
-
- png_composite(*(sp + 1), *(sp + 1), a,
- png_ptr->background.green);
-
- png_composite(*(sp + 2), *(sp + 2), a,
- png_ptr->background.blue);
- }
- }
- }
- }
- else /* if (row_info->bit_depth == 16) */
- {
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
- gamma_16_to_1 != NULL)
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 8)
- {
- png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
- << 8) + (png_uint_16)(*(sp + 7)));
-
- if (a == (png_uint_16)0xffff)
- {
- png_uint_16 v;
-
- v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
- *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 if (a == 0)
- {
- /* Background is already in screen gamma */
- *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
- *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
- *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
- & 0xff);
- *(sp + 3) = (png_byte)(png_ptr->background.green
- & 0xff);
- *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
- & 0xff);
- *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
- }
-
- else
- {
- png_uint_16 v, w;
-
- v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
- png_composite_16(w, v, a, png_ptr->background_1.red);
- if (!optimize)
- w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >>
- 8];
- *sp = (png_byte)((w >> 8) & 0xff);
- *(sp + 1) = (png_byte)(w & 0xff);
-
- v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
- png_composite_16(w, v, a, png_ptr->background_1.green);
- if (!optimize)
- w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >>
- 8];
-
- *(sp + 2) = (png_byte)((w >> 8) & 0xff);
- *(sp + 3) = (png_byte)(w & 0xff);
-
- v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
- png_composite_16(w, v, a, png_ptr->background_1.blue);
- if (!optimize)
- w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >>
- 8];
-
- *(sp + 4) = (png_byte)((w >> 8) & 0xff);
- *(sp + 5) = (png_byte)(w & 0xff);
- }
- }
- }
-
- else
-#endif
- {
- sp = row;
- for (i = 0; i < row_width; i++, sp += 8)
- {
- png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
- << 8) + (png_uint_16)(*(sp + 7)));
-
- if (a == 0)
- {
- *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
- *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
- *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
- & 0xff);
- *(sp + 3) = (png_byte)(png_ptr->background.green
- & 0xff);
- *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
- & 0xff);
- *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
- }
-
- else if (a < 0xffff)
- {
- png_uint_16 v;
-
- png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
- png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
- + *(sp + 3));
- png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
- + *(sp + 5));
-
- png_composite_16(v, r, a, png_ptr->background.red);
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
-
- png_composite_16(v, g, a, png_ptr->background.green);
- *(sp + 2) = (png_byte)((v >> 8) & 0xff);
- *(sp + 3) = (png_byte)(v & 0xff);
-
- png_composite_16(v, b, a, png_ptr->background.blue);
- *(sp + 4) = (png_byte)((v >> 8) & 0xff);
- *(sp + 5) = (png_byte)(v & 0xff);
- }
- }
- }
- }
- break;
- }
-
- default:
- break;
- }
- }
-}
-#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_READ_ALPHA_MODE_SUPPORTED */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-/* Gamma correct the image, avoiding the alpha channel. Make sure
- * you do this after you deal with the transparency issue on grayscale
- * or RGB images. If your bit depth is 8, use gamma_table, if it
- * is 16, use gamma_16_table and gamma_shift. Build these with
- * build_gamma_table().
- */
-void /* PRIVATE */
-png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
-{
- png_const_bytep gamma_table = png_ptr->gamma_table;
- png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
- int gamma_shift = png_ptr->gamma_shift;
-
- png_bytep sp;
- png_uint_32 i;
- png_uint_32 row_width=row_info->width;
-
- png_debug(1, "in png_do_gamma");
-
- if (((row_info->bit_depth <= 8 && gamma_table != NULL) ||
- (row_info->bit_depth == 16 && gamma_16_table != NULL)))
- {
- switch (row_info->color_type)
- {
- case PNG_COLOR_TYPE_RGB:
- {
- if (row_info->bit_depth == 8)
- {
- sp = row;
- for (i = 0; i < row_width; i++)
- {
- *sp = gamma_table[*sp];
- sp++;
- *sp = gamma_table[*sp];
- sp++;
- *sp = gamma_table[*sp];
- sp++;
- }
- }
-
- else /* if (row_info->bit_depth == 16) */
- {
- sp = row;
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 v;
-
- v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- sp += 2;
-
- v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- sp += 2;
-
- v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- sp += 2;
- }
- }
- break;
- }
-
- case PNG_COLOR_TYPE_RGB_ALPHA:
- {
- if (row_info->bit_depth == 8)
- {
- sp = row;
- for (i = 0; i < row_width; i++)
- {
- *sp = gamma_table[*sp];
- sp++;
-
- *sp = gamma_table[*sp];
- sp++;
-
- *sp = gamma_table[*sp];
- sp++;
-
- sp++;
- }
- }
-
- else /* if (row_info->bit_depth == 16) */
- {
- sp = row;
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- sp += 2;
-
- v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- sp += 2;
-
- v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- sp += 4;
- }
- }
- break;
- }
-
- case PNG_COLOR_TYPE_GRAY_ALPHA:
- {
- if (row_info->bit_depth == 8)
- {
- sp = row;
- for (i = 0; i < row_width; i++)
- {
- *sp = gamma_table[*sp];
- sp += 2;
- }
- }
-
- else /* if (row_info->bit_depth == 16) */
- {
- sp = row;
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- sp += 4;
- }
- }
- break;
- }
-
- case PNG_COLOR_TYPE_GRAY:
- {
- if (row_info->bit_depth == 2)
- {
- sp = row;
- for (i = 0; i < row_width; i += 4)
- {
- int a = *sp & 0xc0;
- int b = *sp & 0x30;
- int c = *sp & 0x0c;
- int d = *sp & 0x03;
-
- *sp = (png_byte)(
- ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)]) ) & 0xc0)|
- ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
- ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
- ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
- sp++;
- }
- }
-
- if (row_info->bit_depth == 4)
- {
- sp = row;
- for (i = 0; i < row_width; i += 2)
- {
- int msb = *sp & 0xf0;
- int lsb = *sp & 0x0f;
-
- *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
- | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
- sp++;
- }
- }
-
- else if (row_info->bit_depth == 8)
- {
- sp = row;
- for (i = 0; i < row_width; i++)
- {
- *sp = gamma_table[*sp];
- sp++;
- }
- }
-
- else if (row_info->bit_depth == 16)
- {
- sp = row;
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
- *sp = (png_byte)((v >> 8) & 0xff);
- *(sp + 1) = (png_byte)(v & 0xff);
- sp += 2;
- }
- }
- break;
- }
-
- default:
- break;
- }
- }
-}
-#endif
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-/* Encode the alpha channel to the output gamma (the input channel is always
- * linear.) Called only with color types that have an alpha channel. Needs the
- * from_1 tables.
- */
-void /* PRIVATE */
-png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
-{
- png_uint_32 row_width = row_info->width;
-
- png_debug(1, "in png_do_encode_alpha");
-
- if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
- {
- if (row_info->bit_depth == 8)
- {
- PNG_CONST png_bytep table = png_ptr->gamma_from_1;
-
- if (table != NULL)
- {
- PNG_CONST int step =
- (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
-
- /* The alpha channel is the last component: */
- row += step - 1;
-
- for (; row_width > 0; --row_width, row += step)
- *row = table[*row];
-
- return;
- }
- }
-
- else if (row_info->bit_depth == 16)
- {
- PNG_CONST png_uint_16pp table = png_ptr->gamma_16_from_1;
- PNG_CONST int gamma_shift = png_ptr->gamma_shift;
-
- if (table != NULL)
- {
- PNG_CONST int step =
- (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
-
- /* The alpha channel is the last component: */
- row += step - 2;
-
- for (; row_width > 0; --row_width, row += step)
- {
- png_uint_16 v;
-
- v = table[*(row + 1) >> gamma_shift][*row];
- *row = (png_byte)((v >> 8) & 0xff);
- *(row + 1) = (png_byte)(v & 0xff);
- }
-
- return;
- }
- }
- }
-
- /* Only get to here if called with a weird row_info; no harm has been done,
- * so just issue a warning.
- */
- png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
-}
-#endif
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* Expands a palette row to an RGB or RGBA row depending
- * upon whether you supply trans and num_trans.
- */
-void /* PRIVATE */
-png_do_expand_palette(png_row_infop row_info, png_bytep row,
- png_const_colorp palette, png_const_bytep trans_alpha, int num_trans)
-{
- int shift, value;
- png_bytep sp, dp;
- png_uint_32 i;
- png_uint_32 row_width=row_info->width;
-
- png_debug(1, "in png_do_expand_palette");
-
- if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
- {
- if (row_info->bit_depth < 8)
- {
- switch (row_info->bit_depth)
- {
- case 1:
- {
- sp = row + (png_size_t)((row_width - 1) >> 3);
- dp = row + (png_size_t)row_width - 1;
- shift = 7 - (int)((row_width + 7) & 0x07);
- for (i = 0; i < row_width; i++)
- {
- if ((*sp >> shift) & 0x01)
- *dp = 1;
-
- else
- *dp = 0;
-
- if (shift == 7)
- {
- shift = 0;
- sp--;
- }
-
- else
- shift++;
-
- dp--;
- }
- break;
- }
-
- case 2:
- {
- sp = row + (png_size_t)((row_width - 1) >> 2);
- dp = row + (png_size_t)row_width - 1;
- shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
- for (i = 0; i < row_width; i++)
- {
- value = (*sp >> shift) & 0x03;
- *dp = (png_byte)value;
- if (shift == 6)
- {
- shift = 0;
- sp--;
- }
-
- else
- shift += 2;
-
- dp--;
- }
- break;
- }
-
- case 4:
- {
- sp = row + (png_size_t)((row_width - 1) >> 1);
- dp = row + (png_size_t)row_width - 1;
- shift = (int)((row_width & 0x01) << 2);
- for (i = 0; i < row_width; i++)
- {
- value = (*sp >> shift) & 0x0f;
- *dp = (png_byte)value;
- if (shift == 4)
- {
- shift = 0;
- sp--;
- }
-
- else
- shift += 4;
-
- dp--;
- }
- break;
- }
-
- default:
- break;
- }
- row_info->bit_depth = 8;
- row_info->pixel_depth = 8;
- row_info->rowbytes = row_width;
- }
-
- if (row_info->bit_depth == 8)
- {
- {
- if (num_trans > 0)
- {
- sp = row + (png_size_t)row_width - 1;
- dp = row + (png_size_t)(row_width << 2) - 1;
-
- for (i = 0; i < row_width; i++)
- {
- if ((int)(*sp) >= num_trans)
- *dp-- = 0xff;
-
- else
- *dp-- = trans_alpha[*sp];
-
- *dp-- = palette[*sp].blue;
- *dp-- = palette[*sp].green;
- *dp-- = palette[*sp].red;
- sp--;
- }
- row_info->bit_depth = 8;
- row_info->pixel_depth = 32;
- row_info->rowbytes = row_width * 4;
- row_info->color_type = 6;
- row_info->channels = 4;
- }
-
- else
- {
- sp = row + (png_size_t)row_width - 1;
- dp = row + (png_size_t)(row_width * 3) - 1;
-
- for (i = 0; i < row_width; i++)
- {
- *dp-- = palette[*sp].blue;
- *dp-- = palette[*sp].green;
- *dp-- = palette[*sp].red;
- sp--;
- }
-
- row_info->bit_depth = 8;
- row_info->pixel_depth = 24;
- row_info->rowbytes = row_width * 3;
- row_info->color_type = 2;
- row_info->channels = 3;
- }
- }
- }
- }
-}
-
-/* If the bit depth < 8, it is expanded to 8. Also, if the already
- * expanded transparency value is supplied, an alpha channel is built.
- */
-void /* PRIVATE */
-png_do_expand(png_row_infop row_info, png_bytep row,
- png_const_color_16p trans_color)
-{
- int shift, value;
- png_bytep sp, dp;
- png_uint_32 i;
- png_uint_32 row_width=row_info->width;
-
- png_debug(1, "in png_do_expand");
-
- {
- if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
- {
- unsigned int gray = trans_color ? trans_color->gray : 0;
-
- if (row_info->bit_depth < 8)
- {
- switch (row_info->bit_depth)
- {
- case 1:
- {
- gray = (gray & 0x01) * 0xff;
- sp = row + (png_size_t)((row_width - 1) >> 3);
- dp = row + (png_size_t)row_width - 1;
- shift = 7 - (int)((row_width + 7) & 0x07);
- for (i = 0; i < row_width; i++)
- {
- if ((*sp >> shift) & 0x01)
- *dp = 0xff;
-
- else
- *dp = 0;
-
- if (shift == 7)
- {
- shift = 0;
- sp--;
- }
-
- else
- shift++;
-
- dp--;
- }
- break;
- }
-
- case 2:
- {
- gray = (gray & 0x03) * 0x55;
- sp = row + (png_size_t)((row_width - 1) >> 2);
- dp = row + (png_size_t)row_width - 1;
- shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
- for (i = 0; i < row_width; i++)
- {
- value = (*sp >> shift) & 0x03;
- *dp = (png_byte)(value | (value << 2) | (value << 4) |
- (value << 6));
- if (shift == 6)
- {
- shift = 0;
- sp--;
- }
-
- else
- shift += 2;
-
- dp--;
- }
- break;
- }
-
- case 4:
- {
- gray = (gray & 0x0f) * 0x11;
- sp = row + (png_size_t)((row_width - 1) >> 1);
- dp = row + (png_size_t)row_width - 1;
- shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
- for (i = 0; i < row_width; i++)
- {
- value = (*sp >> shift) & 0x0f;
- *dp = (png_byte)(value | (value << 4));
- if (shift == 4)
- {
- shift = 0;
- sp--;
- }
-
- else
- shift = 4;
-
- dp--;
- }
- break;
- }
-
- default:
- break;
- }
-
- row_info->bit_depth = 8;
- row_info->pixel_depth = 8;
- row_info->rowbytes = row_width;
- }
-
- if (trans_color != NULL)
- {
- if (row_info->bit_depth == 8)
- {
- gray = gray & 0xff;
- sp = row + (png_size_t)row_width - 1;
- dp = row + (png_size_t)(row_width << 1) - 1;
-
- for (i = 0; i < row_width; i++)
- {
- if (*sp == gray)
- *dp-- = 0;
-
- else
- *dp-- = 0xff;
-
- *dp-- = *sp--;
- }
- }
-
- else if (row_info->bit_depth == 16)
- {
- unsigned int gray_high = (gray >> 8) & 0xff;
- unsigned int gray_low = gray & 0xff;
- sp = row + row_info->rowbytes - 1;
- dp = row + (row_info->rowbytes << 1) - 1;
- for (i = 0; i < row_width; i++)
- {
- if (*(sp - 1) == gray_high && *(sp) == gray_low)
- {
- *dp-- = 0;
- *dp-- = 0;
- }
-
- else
- {
- *dp-- = 0xff;
- *dp-- = 0xff;
- }
-
- *dp-- = *sp--;
- *dp-- = *sp--;
- }
- }
-
- row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
- row_info->channels = 2;
- row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
- row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
- row_width);
- }
- }
- else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color)
- {
- if (row_info->bit_depth == 8)
- {
- png_byte red = (png_byte)(trans_color->red & 0xff);
- png_byte green = (png_byte)(trans_color->green & 0xff);
- png_byte blue = (png_byte)(trans_color->blue & 0xff);
- sp = row + (png_size_t)row_info->rowbytes - 1;
- dp = row + (png_size_t)(row_width << 2) - 1;
- for (i = 0; i < row_width; i++)
- {
- if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
- *dp-- = 0;
-
- else
- *dp-- = 0xff;
-
- *dp-- = *sp--;
- *dp-- = *sp--;
- *dp-- = *sp--;
- }
- }
- else if (row_info->bit_depth == 16)
- {
- png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
- png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
- png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
- png_byte red_low = (png_byte)(trans_color->red & 0xff);
- png_byte green_low = (png_byte)(trans_color->green & 0xff);
- png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
- sp = row + row_info->rowbytes - 1;
- dp = row + (png_size_t)(row_width << 3) - 1;
- for (i = 0; i < row_width; i++)
- {
- if (*(sp - 5) == red_high &&
- *(sp - 4) == red_low &&
- *(sp - 3) == green_high &&
- *(sp - 2) == green_low &&
- *(sp - 1) == blue_high &&
- *(sp ) == blue_low)
- {
- *dp-- = 0;
- *dp-- = 0;
- }
-
- else
- {
- *dp-- = 0xff;
- *dp-- = 0xff;
- }
-
- *dp-- = *sp--;
- *dp-- = *sp--;
- *dp-- = *sp--;
- *dp-- = *sp--;
- *dp-- = *sp--;
- *dp-- = *sp--;
- }
- }
- row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
- row_info->channels = 4;
- row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
- row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
- }
- }
-}
-#endif
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* If the bit depth is 8 and the color type is not a palette type expand the
- * whole row to 16 bits. Has no effect otherwise.
- */
-void /* PRIVATE */
-png_do_expand_16(png_row_infop row_info, png_bytep row)
-{
- if (row_info->bit_depth == 8 &&
- row_info->color_type != PNG_COLOR_TYPE_PALETTE)
- {
- /* The row have a sequence of bytes containing [0..255] and we need
- * to turn it into another row containing [0..65535], to do this we
- * calculate:
- *
- * (input / 255) * 65535
- *
- * Which happens to be exactly input * 257 and this can be achieved
- * simply by byte replication in place (copying backwards).
- */
- png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */
- png_byte *dp = sp + row_info->rowbytes; /* destination, end + 1 */
- while (dp > sp)
- dp[-2] = dp[-1] = *--sp, dp -= 2;
-
- row_info->rowbytes *= 2;
- row_info->bit_depth = 16;
- row_info->pixel_depth = (png_byte)(row_info->channels * 16);
- }
-}
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-void /* PRIVATE */
-png_do_quantize(png_row_infop row_info, png_bytep row,
- png_const_bytep palette_lookup, png_const_bytep quantize_lookup)
-{
- png_bytep sp, dp;
- png_uint_32 i;
- png_uint_32 row_width=row_info->width;
-
- png_debug(1, "in png_do_quantize");
-
- if (row_info->bit_depth == 8)
- {
- if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup)
- {
- int r, g, b, p;
- sp = row;
- dp = row;
- for (i = 0; i < row_width; i++)
- {
- r = *sp++;
- g = *sp++;
- b = *sp++;
-
- /* This looks real messy, but the compiler will reduce
- * it down to a reasonable formula. For example, with
- * 5 bits per color, we get:
- * p = (((r >> 3) & 0x1f) << 10) |
- * (((g >> 3) & 0x1f) << 5) |
- * ((b >> 3) & 0x1f);
- */
- p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
- ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
- (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
- (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
- ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
- (PNG_QUANTIZE_BLUE_BITS)) |
- ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
- ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
-
- *dp++ = palette_lookup[p];
- }
-
- row_info->color_type = PNG_COLOR_TYPE_PALETTE;
- row_info->channels = 1;
- row_info->pixel_depth = row_info->bit_depth;
- row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
- }
-
- else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
- palette_lookup != NULL)
- {
- int r, g, b, p;
- sp = row;
- dp = row;
- for (i = 0; i < row_width; i++)
- {
- r = *sp++;
- g = *sp++;
- b = *sp++;
- sp++;
-
- p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
- ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
- (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
- (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
- ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
- (PNG_QUANTIZE_BLUE_BITS)) |
- ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
- ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
-
- *dp++ = palette_lookup[p];
- }
-
- row_info->color_type = PNG_COLOR_TYPE_PALETTE;
- row_info->channels = 1;
- row_info->pixel_depth = row_info->bit_depth;
- row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
- }
-
- else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
- quantize_lookup)
- {
- sp = row;
-
- for (i = 0; i < row_width; i++, sp++)
- {
- *sp = quantize_lookup[*sp];
- }
- }
- }
-}
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-/* Undoes intrapixel differencing */
-void /* PRIVATE */
-png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
-{
- png_debug(1, "in png_do_read_intrapixel");
-
- if (
- (row_info->color_type & PNG_COLOR_MASK_COLOR))
- {
- int bytes_per_pixel;
- png_uint_32 row_width = row_info->width;
-
- if (row_info->bit_depth == 8)
- {
- png_bytep rp;
- png_uint_32 i;
-
- if (row_info->color_type == PNG_COLOR_TYPE_RGB)
- bytes_per_pixel = 3;
-
- else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
- bytes_per_pixel = 4;
-
- else
- return;
-
- for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
- {
- *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
- *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
- }
- }
- else if (row_info->bit_depth == 16)
- {
- png_bytep rp;
- png_uint_32 i;
-
- if (row_info->color_type == PNG_COLOR_TYPE_RGB)
- bytes_per_pixel = 6;
-
- else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
- bytes_per_pixel = 8;
-
- else
- return;
-
- for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
- {
- png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
- png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
- png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
- png_uint_32 red = (s0 + s1 + 65536) & 0xffff;
- png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
- *(rp ) = (png_byte)((red >> 8) & 0xff);
- *(rp + 1) = (png_byte)(red & 0xff);
- *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
- *(rp + 5) = (png_byte)(blue & 0xff);
- }
- }
- }
-}
-#endif /* PNG_MNG_FEATURES_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED */
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