diff options
Diffstat (limited to 'third_party/libpng/pngrtran.c')
| -rw-r--r-- | third_party/libpng/pngrtran.c | 4997 |
1 files changed, 0 insertions, 4997 deletions
diff --git a/third_party/libpng/pngrtran.c b/third_party/libpng/pngrtran.c deleted file mode 100644 index f129ef129c..0000000000 --- a/third_party/libpng/pngrtran.c +++ /dev/null @@ -1,4997 +0,0 @@ - -/* pngrtran.c - transforms the data in a row for PNG readers - * - * Last changed in libpng 1.6.19 [November 12, 2015] - * Copyright (c) 1998-2015 Glenn Randers-Pehrson - * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) - * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) - * - * This code is released under the libpng license. - * For conditions of distribution and use, see the disclaimer - * and license in png.h - * - * This file contains functions optionally called by an application - * in order to tell libpng how to handle data when reading a PNG. - * Transformations that are used in both reading and writing are - * in pngtrans.c. - */ - -#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 need_IHDR 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) != 0) - 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) == 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 != 0) - 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) == 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) == 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) == 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 != 0) - 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 != 0) - 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) == 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 != 0) - { - /* 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) != 0) - 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 than 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) == 0) - return; - - png_ptr->transformations |= PNG_QUANTIZE; - - if (full_quantize == 0) - { - 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 != 0) - break; - } - - /* Swap the palette around, and set up a table, if necessary */ - if (full_quantize != 0) - { - 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 == 0) - { - 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 != 0) - { - 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 /* READ_QUANTIZE */ - -#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) == 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 */ -#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) == 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) == 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) == 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) == 0) - return; - - png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); -} -#endif /* READ_EXPAND */ - -#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) == 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) == 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) == 0) - 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"); - } - - 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_transparency = 1; - input_has_alpha = 1; - break; - } - } - } - - /* If no alpha we can optimize. */ - if (input_has_alpha == 0) - { - /* Any alpha means background and associative alpha processing is - * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA - * and ENCODE_ALPHA are irrelevant. - */ - png_ptr->transformations &= ~PNG_ENCODE_ALPHA; - png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; - - if (input_has_transparency == 0) - 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) != 0 && - (png_ptr->transformations & PNG_EXPAND) != 0) - { - { - 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) != 0) - { - if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0) - { - /* 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 /* READ_INVERT_ALPHA */ - } - } /* background expand and (therefore) no alpha association. */ -#endif /* READ_EXPAND && READ_BACKGROUND */ -} - -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 == 0) - { - /* Any alpha means background and associative alpha processing is - * required, however if the alpha is 0 or 1 throughout OPTIMIZE_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 == 0) - 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) != 0 && - (png_ptr->transformations & PNG_EXPAND) != 0 && - (png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) - /* 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) == 0) - { - 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 /* READ_EXPAND && READ_BACKGROUND */ -} - -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 != 0) - 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_INVERT_ALPHA - * 16) PNG_SHIFT - * 17) PNG_PACK - * 18) PNG_BGR - * 19) PNG_PACKSWAP - * 20) PNG_FILLER (includes PNG_ADD_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) != 0 && - (png_ptr->transformations & PNG_COMPOSE) == 0) - { - /* 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) == 0) - { - 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) != 0) - 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) != 0) - { - /* 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) == 0) - png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; - } - - else if ((png_ptr->transformations & PNG_COMPOSE) != 0) - { - /* 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) != 0) - { - 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 /* READ_EXPAND && READ_BACKGROUND */ -#endif /* READ_GRAY_TO_RGB */ - - /* 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) != 0 && - (png_ptr->transformations & PNG_COMPOSE) != 0 && - (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 && - 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 /* READ_BACKGROUND && READ_EXPAND_16 */ - -#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)) != 0 && - (png_ptr->transformations & PNG_COMPOSE) != 0 && - (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 && - 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) != 0 || - ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0 && - (png_gamma_significant(png_ptr->colorspace.gamma) != 0 || - png_gamma_significant(png_ptr->screen_gamma) != 0)) || - ((png_ptr->transformations & PNG_COMPOSE) != 0 && - (png_gamma_significant(png_ptr->colorspace.gamma) != 0 || - png_gamma_significant(png_ptr->screen_gamma) != 0 -# ifdef PNG_READ_BACKGROUND_SUPPORTED - || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE && - png_gamma_significant(png_ptr->background_gamma) != 0) -# endif - )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 && - png_gamma_significant(png_ptr->screen_gamma) != 0)) - { - png_build_gamma_table(png_ptr, png_ptr->bit_depth); - -#ifdef PNG_READ_BACKGROUND_SUPPORTED - if ((png_ptr->transformations & PNG_COMPOSE) != 0) - { - /* 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) != 0) - png_warning(png_ptr, - "libpng does not support gamma+background+rgb_to_gray"); - - if ((png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) != 0) - { - /* 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) != 0) - { - 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) != 0) - { - 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 != 0) - png_ptr->background_1.gray = png_gamma_correct(png_ptr, - png_ptr->background.gray, g); - - if (gs_sig != 0) - 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 != 0) - { - 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 != 0) - { - 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 /* READ_BACKGROUND */ - 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 /* READ_GAMMA */ - -#ifdef PNG_READ_BACKGROUND_SUPPORTED - /* No GAMMA transformation (see the hanging else 4 lines above) */ - if ((png_ptr->transformations & PNG_COMPOSE) != 0 && - (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; - } -#endif /* READ_BACKGROUND */ - -#ifdef PNG_READ_SHIFT_SUPPORTED - if ((png_ptr->transformations & PNG_SHIFT) != 0 && - (png_ptr->transformations & PNG_EXPAND) == 0 && - (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 /* READ_SHIFT */ -} - -/* 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) != 0) - { - 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; - - if (png_ptr->palette == NULL) - png_error (png_ptr, "Palette is NULL in indexed image"); - } - else - { - if (png_ptr->num_trans != 0) - { - if ((png_ptr->transformations & PNG_EXPAND_tRNS) != 0) - 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) != 0) - 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) != 0) - info_ptr->bit_depth = 8; -# endif - -# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED - if ((png_ptr->transformations & PNG_16_TO_8) != 0) - 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 */ - } - -#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED - if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0) - 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) != 0) - 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) != 0) - { - if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) || - (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) && - png_ptr->palette_lookup != 0 && 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) != 0 && - 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) != 0 && - (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) != 0) - info_ptr->channels = 3; - - else - info_ptr->channels = 1; - -#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED - if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0) - { - 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) != 0) - info_ptr->channels++; - -#ifdef PNG_READ_FILLER_SUPPORTED - /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */ - if ((png_ptr->transformations & PNG_FILLER) != 0 && - (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) != 0) - 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) != 0) - { - if (png_ptr->user_transform_depth != 0) - info_ptr->bit_depth = png_ptr->user_transform_depth; - - if (png_ptr->user_transform_channels != 0) - 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 != NULL) - return; -#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. - */ -static void -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. - */ -static void -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) != 0) - { - 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) != 0) - { - 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 == 0) - 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; - } - break; - } -#endif - } - } -} -#endif - -#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED -/* Scale rows of bit depth 16 down to 8 accurately */ -static void -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 -static void -/* 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 -static void -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 -static void -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 */ -static void -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); -#endif - png_byte lo_filler = (png_byte)filler; - - 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) != 0) - { - /* 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) != 0) - { - /* 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) = lo_filler; - *(--dp) = hi_filler; - *(--dp) = *(--sp); - *(--dp) = *(--sp); - } - *(--dp) = lo_filler; - *(--dp) = hi_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) = lo_filler; - *(--dp) = hi_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) != 0) - { - /* 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) != 0) - { - /* 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) = lo_filler; - *(--dp) = hi_filler; - *(--dp) = *(--sp); - *(--dp) = *(--sp); - *(--dp) = *(--sp); - *(--dp) = *(--sp); - *(--dp) = *(--sp); - *(--dp) = *(--sp); - } - *(--dp) = lo_filler; - *(--dp) = hi_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) = lo_filler; - *(--dp) = hi_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 */ -static void -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) == 0) - { - 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. - */ -static int -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) == 0 && - (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0) - { - 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 != 0) - *(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 != 0) - *(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; - png_byte hi,lo; - - hi=*(sp)++; lo=*(sp)++; red = (png_uint_16)((hi << 8) | (lo)); - hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo)); - hi=*(sp)++; lo=*(sp)++; blue = (png_uint_16)((hi << 8) | (lo)); - - if (red == green && red == blue) - { - 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 != 0) - { - *(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; - png_byte hi,lo; - - hi=*(sp)++; lo=*(sp)++; red = (png_uint_16)((hi << 8) | (lo)); - hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo)); - hi=*(sp)++; lo=*(sp)++; blue = (png_uint_16)((hi << 8) | (lo)); - - if (red != green || red != blue) - rgb_error |= 1; - - /* 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 != 0) - { - *(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 - -#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. - */ -static void -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 == 0) - { - 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 == 0) - { - 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 == 0) - { - 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 & (0x0f0f >> (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 & (0x0f0f >> (4 - shift)); - tmp |= g << shift; - *sp = (png_byte)(tmp & 0xff); - } - - if (shift == 0) - { - 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 & (0x0f0f >> (4 - shift)); - tmp |= png_ptr->background.gray << shift; - *sp = (png_byte)(tmp & 0xff); - } - - if (shift == 0) - { - 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 == 0) - 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 != 0) - 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 == 0) 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 == 0) 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 == 0) 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 == 0) - 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 == 0) - 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 == 0) - 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 /* READ_BACKGROUND || READ_ALPHA_MODE */ - -#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(). - */ -static void -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. - */ -static void -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) != 0) - { - 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. - */ -static void -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. - */ -static void -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 != NULL ? 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 & 0xffU) == 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) & 0xffU) == gray_high && - (*(sp) & 0xffU) == 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 != NULL) - { - 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. - */ -static void -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 -static void -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 /* READ_QUANTIZE */ - -/* 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) == 0) - { - /* 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) != 0) - { - 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 != 0 && - (png_ptr->transformations & PNG_EXPAND_tRNS) != 0) - 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) != 0 && - (png_ptr->transformations & PNG_COMPOSE) == 0 && - (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) != 0) - { - int rgb_error = - png_do_rgb_to_gray(png_ptr, row_info, - png_ptr->row_buf + 1); - - if (rgb_error != 0) - { - 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) != 0 && - (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) == 0) - 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) != 0) - png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr); -#endif - -#ifdef PNG_READ_GAMMA_SUPPORTED - if ((png_ptr->transformations & PNG_GAMMA) != 0 && -#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED - /* Because RGB_TO_GRAY does the gamma transform. */ - (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0 && -#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) != 0 && - ((png_ptr->num_trans != 0) || - (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)) && -#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) != 0 && - (png_ptr->transformations & PNG_COMPOSE) != 0 && - (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) != 0 && - (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0) - 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) != 0) - 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) != 0) - png_do_chop(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_QUANTIZE_SUPPORTED - if ((png_ptr->transformations & PNG_QUANTIZE) != 0) - { - 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 /* READ_QUANTIZE */ - -#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) != 0) - 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) != 0 && - (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) != 0) - 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) != 0) - png_do_invert(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED - if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0) - png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_SHIFT_SUPPORTED - if ((png_ptr->transformations & PNG_SHIFT) != 0) - 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) != 0) - 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) != 0) - png_do_bgr(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_PACKSWAP_SUPPORTED - if ((png_ptr->transformations & PNG_PACKSWAP) != 0) - png_do_packswap(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_FILLER_SUPPORTED - if ((png_ptr->transformations & PNG_FILLER) != 0) - png_do_read_filler(row_info, png_ptr->row_buf + 1, - (png_uint_32)png_ptr->filler, png_ptr->flags); -#endif - -#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED - if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0) - 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) != 0) - 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) != 0) - { - 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 != 0) - row_info->bit_depth = png_ptr->user_transform_depth; - - if (png_ptr->user_transform_channels != 0) - 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 -} - -#endif /* READ_TRANSFORMS */ -#endif /* READ */ |