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Diffstat (limited to 'third_party/libpng/pngrtran.c')
| -rw-r--r-- | third_party/libpng/pngrtran.c | 4292 |
1 files changed, 4292 insertions, 0 deletions
diff --git a/third_party/libpng/pngrtran.c b/third_party/libpng/pngrtran.c new file mode 100644 index 0000000..873b22c --- /dev/null +++ b/third_party/libpng/pngrtran.c @@ -0,0 +1,4292 @@ + +/* pngrtran.c - transforms the data in a row for PNG readers + * + * Last changed in libpng 1.2.27 [April 29, 2008] + * For conditions of distribution and use, see copyright notice in png.h + * Copyright (c) 1998-2008 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 file contains functions optionally called by an application + * in order to tell libpng how to handle data when reading a PNG. + * Transformations that are used in both reading and writing are + * in pngtrans.c. + */ + +#define PNG_INTERNAL +#include "png.h" + +#if defined(PNG_READ_SUPPORTED) + +/* Set the action on getting a CRC error for an ancillary or critical chunk. */ +void PNGAPI +png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action) +{ + png_debug(1, "in png_set_crc_action\n"); + /* Tell libpng how we react to CRC errors in critical chunks */ + if(png_ptr == NULL) return; + 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; + } + + switch (ancil_action) + { + case PNG_CRC_NO_CHANGE: /* leave setting as is */ + break; + case PNG_CRC_WARN_USE: /* warn/use data */ + png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; + png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE; + break; + case PNG_CRC_QUIET_USE: /* quiet/use data */ + png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; + png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE | + PNG_FLAG_CRC_ANCILLARY_NOWARN; + break; + case PNG_CRC_ERROR_QUIT: /* error/quit */ + png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; + png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN; + break; + case PNG_CRC_WARN_DISCARD: /* warn/discard data */ + case PNG_CRC_DEFAULT: + default: + png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; + break; + } +} + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ + defined(PNG_FLOATING_POINT_SUPPORTED) +/* handle alpha and tRNS via a background color */ +void PNGAPI +png_set_background(png_structp png_ptr, + png_color_16p background_color, int background_gamma_code, + int need_expand, double background_gamma) +{ + png_debug(1, "in png_set_background\n"); + if(png_ptr == NULL) return; + if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN) + { + png_warning(png_ptr, "Application must supply a known background gamma"); + return; + } + + png_ptr->transformations |= PNG_BACKGROUND; + png_memcpy(&(png_ptr->background), background_color, + png_sizeof(png_color_16)); + png_ptr->background_gamma = (float)background_gamma; + png_ptr->background_gamma_type = (png_byte)(background_gamma_code); + png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0); +} +#endif + +#if defined(PNG_READ_16_TO_8_SUPPORTED) +/* strip 16 bit depth files to 8 bit depth */ +void PNGAPI +png_set_strip_16(png_structp png_ptr) +{ + png_debug(1, "in png_set_strip_16\n"); + if(png_ptr == NULL) return; + png_ptr->transformations |= PNG_16_TO_8; +} +#endif + +#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED) +void PNGAPI +png_set_strip_alpha(png_structp png_ptr) +{ + png_debug(1, "in png_set_strip_alpha\n"); + if(png_ptr == NULL) return; + png_ptr->flags |= PNG_FLAG_STRIP_ALPHA; +} +#endif + +#if defined(PNG_READ_DITHER_SUPPORTED) +/* Dither file to 8 bit. Supply a palette, the current number + * of elements in the palette, the maximum number of elements + * allowed, and a histogram if possible. If the current number + * of colors is greater then the maximum number, the palette will be + * modified to fit in the maximum number. "full_dither" indicates + * whether we need a dithering cube set up for RGB images, or if we + * simply are reducing the number of colors in a paletted image. + */ + +typedef struct png_dsort_struct +{ + struct png_dsort_struct FAR * next; + png_byte left; + png_byte right; +} png_dsort; +typedef png_dsort FAR * png_dsortp; +typedef png_dsort FAR * FAR * png_dsortpp; + +void PNGAPI +png_set_dither(png_structp png_ptr, png_colorp palette, + int num_palette, int maximum_colors, png_uint_16p histogram, + int full_dither) +{ + png_debug(1, "in png_set_dither\n"); + if(png_ptr == NULL) return; + png_ptr->transformations |= PNG_DITHER; + + if (!full_dither) + { + int i; + + png_ptr->dither_index = (png_bytep)png_malloc(png_ptr, + (png_uint_32)(num_palette * png_sizeof (png_byte))); + for (i = 0; i < num_palette; i++) + png_ptr->dither_index[i] = (png_byte)i; + } + + if (num_palette > maximum_colors) + { + if (histogram != NULL) + { + /* This is easy enough, just throw out the least used colors. + Perhaps not the best solution, but good enough. */ + + int i; + + /* initialize an array to sort colors */ + png_ptr->dither_sort = (png_bytep)png_malloc(png_ptr, + (png_uint_32)(num_palette * png_sizeof (png_byte))); + + /* initialize the dither_sort array */ + for (i = 0; i < num_palette; i++) + png_ptr->dither_sort[i] = (png_byte)i; + + /* Find the least used palette entries by starting a + bubble sort, and running it until we have sorted + out enough colors. Note that we don't care about + sorting all the colors, just finding which are + least used. */ + + for (i = num_palette - 1; i >= maximum_colors; i--) + { + int done; /* to stop early if the list is pre-sorted */ + int j; + + done = 1; + for (j = 0; j < i; j++) + { + if (histogram[png_ptr->dither_sort[j]] + < histogram[png_ptr->dither_sort[j + 1]]) + { + png_byte t; + + t = png_ptr->dither_sort[j]; + png_ptr->dither_sort[j] = png_ptr->dither_sort[j + 1]; + png_ptr->dither_sort[j + 1] = t; + done = 0; + } + } + if (done) + break; + } + + /* swap the palette around, and set up a table, if necessary */ + if (full_dither) + { + int j = num_palette; + + /* put all the useful colors within the max, but don't + move the others */ + for (i = 0; i < maximum_colors; i++) + { + if ((int)png_ptr->dither_sort[i] >= maximum_colors) + { + do + j--; + while ((int)png_ptr->dither_sort[j] >= maximum_colors); + palette[i] = palette[j]; + } + } + } + else + { + int j = num_palette; + + /* move all the used colors inside the max limit, and + develop a translation table */ + for (i = 0; i < maximum_colors; i++) + { + /* only move the colors we need to */ + if ((int)png_ptr->dither_sort[i] >= maximum_colors) + { + png_color tmp_color; + + do + j--; + while ((int)png_ptr->dither_sort[j] >= maximum_colors); + + tmp_color = palette[j]; + palette[j] = palette[i]; + palette[i] = tmp_color; + /* indicate where the color went */ + png_ptr->dither_index[j] = (png_byte)i; + png_ptr->dither_index[i] = (png_byte)j; + } + } + + /* find closest color for those colors we are not using */ + for (i = 0; i < num_palette; i++) + { + if ((int)png_ptr->dither_index[i] >= maximum_colors) + { + int min_d, k, min_k, d_index; + + /* find the closest color to one we threw out */ + d_index = png_ptr->dither_index[i]; + min_d = PNG_COLOR_DIST(palette[d_index], palette[0]); + for (k = 1, min_k = 0; k < maximum_colors; k++) + { + int d; + + d = PNG_COLOR_DIST(palette[d_index], palette[k]); + + if (d < min_d) + { + min_d = d; + min_k = k; + } + } + /* point to closest color */ + png_ptr->dither_index[i] = (png_byte)min_k; + } + } + } + png_free(png_ptr, png_ptr->dither_sort); + png_ptr->dither_sort=NULL; + } + else + { + /* This is much harder to do simply (and quickly). Perhaps + we need to go through a median cut routine, but those + don't always behave themselves with only a few colors + as input. So we will just find the closest two colors, + and throw out one of them (chosen somewhat randomly). + [We don't understand this at all, so if someone wants to + work on improving it, be our guest - AED, GRP] + */ + int i; + int max_d; + int num_new_palette; + png_dsortp t; + png_dsortpp hash; + + t=NULL; + + /* initialize palette index arrays */ + png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr, + (png_uint_32)(num_palette * png_sizeof (png_byte))); + png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr, + (png_uint_32)(num_palette * png_sizeof (png_byte))); + + /* initialize the sort array */ + for (i = 0; i < num_palette; i++) + { + png_ptr->index_to_palette[i] = (png_byte)i; + png_ptr->palette_to_index[i] = (png_byte)i; + } + + hash = (png_dsortpp)png_malloc(png_ptr, (png_uint_32)(769 * + png_sizeof (png_dsortp))); + for (i = 0; i < 769; i++) + hash[i] = NULL; +/* png_memset(hash, 0, 769 * png_sizeof (png_dsortp)); */ + + num_new_palette = num_palette; + + /* initial wild guess at how far apart the farthest pixel + pair we will be eliminating will be. Larger + numbers mean more areas will be allocated, Smaller + numbers run the risk of not saving enough data, and + having to do this all over again. + + I have not done extensive checking on this number. + */ + max_d = 96; + + while (num_new_palette > maximum_colors) + { + for (i = 0; i < num_new_palette - 1; i++) + { + int j; + + for (j = i + 1; j < num_new_palette; j++) + { + int d; + + d = PNG_COLOR_DIST(palette[i], palette[j]); + + if (d <= max_d) + { + + t = (png_dsortp)png_malloc_warn(png_ptr, + (png_uint_32)(png_sizeof(png_dsort))); + if (t == NULL) + break; + t->next = hash[d]; + t->left = (png_byte)i; + t->right = (png_byte)j; + hash[d] = t; + } + } + if (t == NULL) + break; + } + + if (t != NULL) + for (i = 0; i <= max_d; i++) + { + if (hash[i] != NULL) + { + png_dsortp p; + + for (p = hash[i]; p; p = p->next) + { + if ((int)png_ptr->index_to_palette[p->left] + < num_new_palette && + (int)png_ptr->index_to_palette[p->right] + < num_new_palette) + { + int j, next_j; + + if (num_new_palette & 0x01) + { + j = p->left; + next_j = p->right; + } + else + { + j = p->right; + next_j = p->left; + } + + num_new_palette--; + palette[png_ptr->index_to_palette[j]] + = palette[num_new_palette]; + if (!full_dither) + { + int k; + + for (k = 0; k < num_palette; k++) + { + if (png_ptr->dither_index[k] == + png_ptr->index_to_palette[j]) + png_ptr->dither_index[k] = + png_ptr->index_to_palette[next_j]; + if ((int)png_ptr->dither_index[k] == + num_new_palette) + png_ptr->dither_index[k] = + png_ptr->index_to_palette[j]; + } + } + + png_ptr->index_to_palette[png_ptr->palette_to_index + [num_new_palette]] = png_ptr->index_to_palette[j]; + png_ptr->palette_to_index[png_ptr->index_to_palette[j]] + = png_ptr->palette_to_index[num_new_palette]; + + png_ptr->index_to_palette[j] = (png_byte)num_new_palette; + png_ptr->palette_to_index[num_new_palette] = (png_byte)j; + } + if (num_new_palette <= maximum_colors) + break; + } + if (num_new_palette <= maximum_colors) + break; + } + } + + for (i = 0; i < 769; i++) + { + if (hash[i] != NULL) + { + png_dsortp p = hash[i]; + while (p) + { + t = p->next; + png_free(png_ptr, p); + p = t; + } + } + hash[i] = 0; + } + max_d += 96; + } + png_free(png_ptr, hash); + png_free(png_ptr, png_ptr->palette_to_index); + png_free(png_ptr, png_ptr->index_to_palette); + png_ptr->palette_to_index=NULL; + png_ptr->index_to_palette=NULL; + } + num_palette = maximum_colors; + } + if (png_ptr->palette == NULL) + { + png_ptr->palette = palette; + } + png_ptr->num_palette = (png_uint_16)num_palette; + + if (full_dither) + { + int i; + png_bytep distance; + int total_bits = PNG_DITHER_RED_BITS + PNG_DITHER_GREEN_BITS + + PNG_DITHER_BLUE_BITS; + int num_red = (1 << PNG_DITHER_RED_BITS); + int num_green = (1 << PNG_DITHER_GREEN_BITS); + int num_blue = (1 << PNG_DITHER_BLUE_BITS); + png_size_t num_entries = ((png_size_t)1 << total_bits); + + png_ptr->palette_lookup = (png_bytep )png_malloc(png_ptr, + (png_uint_32)(num_entries * png_sizeof (png_byte))); + + png_memset(png_ptr->palette_lookup, 0, num_entries * + png_sizeof (png_byte)); + + distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries * + png_sizeof(png_byte))); + + png_memset(distance, 0xff, num_entries * png_sizeof(png_byte)); + + for (i = 0; i < num_palette; i++) + { + int ir, ig, ib; + int r = (palette[i].red >> (8 - PNG_DITHER_RED_BITS)); + int g = (palette[i].green >> (8 - PNG_DITHER_GREEN_BITS)); + int b = (palette[i].blue >> (8 - PNG_DITHER_BLUE_BITS)); + + for (ir = 0; ir < num_red; ir++) + { + /* int dr = abs(ir - r); */ + int dr = ((ir > r) ? ir - r : r - ir); + int index_r = (ir << (PNG_DITHER_BLUE_BITS + PNG_DITHER_GREEN_BITS)); + + for (ig = 0; ig < num_green; ig++) + { + /* int dg = abs(ig - g); */ + int dg = ((ig > g) ? ig - g : g - ig); + int dt = dr + dg; + int dm = ((dr > dg) ? dr : dg); + int index_g = index_r | (ig << PNG_DITHER_BLUE_BITS); + + for (ib = 0; ib < num_blue; ib++) + { + int d_index = index_g | ib; + /* int db = abs(ib - b); */ + int db = ((ib > b) ? ib - b : b - ib); + int dmax = ((dm > db) ? dm : db); + int d = dmax + dt + db; + + if (d < (int)distance[d_index]) + { + distance[d_index] = (png_byte)d; + png_ptr->palette_lookup[d_index] = (png_byte)i; + } + } + } + } + } + + png_free(png_ptr, distance); + } +} +#endif + +#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED) +/* Transform the image from the file_gamma to the screen_gamma. We + * only do transformations on images where the file_gamma and screen_gamma + * are not close reciprocals, otherwise it slows things down slightly, and + * also needlessly introduces small errors. + * + * We will turn off gamma transformation later if no semitransparent entries + * are present in the tRNS array for palette images. We can't do it here + * because we don't necessarily have the tRNS chunk yet. + */ +void PNGAPI +png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma) +{ + png_debug(1, "in png_set_gamma\n"); + if(png_ptr == NULL) return; + if ((fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD) || + (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) || + (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)) + png_ptr->transformations |= PNG_GAMMA; + png_ptr->gamma = (float)file_gamma; + png_ptr->screen_gamma = (float)scrn_gamma; +} +#endif + +#if defined(PNG_READ_EXPAND_SUPPORTED) +/* Expand paletted images to RGB, expand grayscale images of + * less than 8-bit depth to 8-bit depth, and expand tRNS chunks + * to alpha channels. + */ +void PNGAPI +png_set_expand(png_structp png_ptr) +{ + png_debug(1, "in png_set_expand\n"); + if(png_ptr == NULL) return; + png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; +} + +/* GRR 19990627: the following three functions currently are identical + * to png_set_expand(). However, it is entirely reasonable that someone + * might wish to expand an indexed image to RGB but *not* expand a single, + * fully transparent palette entry to a full alpha channel--perhaps instead + * convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace + * the transparent color with a particular RGB value, or drop tRNS entirely. + * IOW, a future version of the library may make the transformations flag + * a bit more fine-grained, with separate bits for each of these three + * functions. + * + * More to the point, these functions make it obvious what libpng will be + * doing, whereas "expand" can (and does) mean any number of things. + * + * GRP 20060307: In libpng-1.4.0, png_set_gray_1_2_4_to_8() was modified + * to expand only the sample depth but not to expand the tRNS to alpha. + */ + +/* Expand paletted images to RGB. */ +void PNGAPI +png_set_palette_to_rgb(png_structp png_ptr) +{ + png_debug(1, "in png_set_palette_to_rgb\n"); + if(png_ptr == NULL) return; + png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; +} + +#if !defined(PNG_1_0_X) +/* Expand grayscale images of less than 8-bit depth to 8 bits. */ +void PNGAPI +png_set_expand_gray_1_2_4_to_8(png_structp png_ptr) +{ + png_debug(1, "in png_set_expand_gray_1_2_4_to_8\n"); + if(png_ptr == NULL) return; + png_ptr->transformations |= PNG_EXPAND; + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; +} +#endif + +#if defined(PNG_1_0_X) || defined(PNG_1_2_X) +/* Expand grayscale images of less than 8-bit depth to 8 bits. */ +/* Deprecated as of libpng-1.2.9 */ +void PNGAPI +png_set_gray_1_2_4_to_8(png_structp png_ptr) +{ + png_debug(1, "in png_set_gray_1_2_4_to_8\n"); + if(png_ptr == NULL) return; + png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); +} +#endif + + +/* Expand tRNS chunks to alpha channels. */ +void PNGAPI +png_set_tRNS_to_alpha(png_structp png_ptr) +{ + png_debug(1, "in png_set_tRNS_to_alpha\n"); + png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; +} +#endif /* defined(PNG_READ_EXPAND_SUPPORTED) */ + +#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) +void PNGAPI +png_set_gray_to_rgb(png_structp png_ptr) +{ + png_debug(1, "in png_set_gray_to_rgb\n"); + png_ptr->transformations |= PNG_GRAY_TO_RGB; + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; +} +#endif + +#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) +#if defined(PNG_FLOATING_POINT_SUPPORTED) +/* Convert a RGB image to a grayscale of the same width. This allows us, + * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image. + */ + +void PNGAPI +png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red, + double green) +{ + int red_fixed = (int)((float)red*100000.0 + 0.5); + int green_fixed = (int)((float)green*100000.0 + 0.5); + if(png_ptr == NULL) return; + png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed); +} +#endif + +void PNGAPI +png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action, + png_fixed_point red, png_fixed_point green) +{ + png_debug(1, "in png_set_rgb_to_gray\n"); + if(png_ptr == NULL) return; + switch(error_action) + { + case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY; + break; + case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN; + break; + case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR; + } + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) +#if defined(PNG_READ_EXPAND_SUPPORTED) + png_ptr->transformations |= PNG_EXPAND; +#else + { + png_warning(png_ptr, "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED."); + png_ptr->transformations &= ~PNG_RGB_TO_GRAY; + } +#endif + { + png_uint_16 red_int, green_int; + if(red < 0 || green < 0) + { + red_int = 6968; /* .212671 * 32768 + .5 */ + green_int = 23434; /* .715160 * 32768 + .5 */ + } + else if(red + green < 100000L) + { + red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L); + green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L); + } + else + { + png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients"); + red_int = 6968; + green_int = 23434; + } + png_ptr->rgb_to_gray_red_coeff = red_int; + png_ptr->rgb_to_gray_green_coeff = green_int; + png_ptr->rgb_to_gray_blue_coeff = (png_uint_16)(32768-red_int-green_int); + } +} +#endif + +#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ + defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \ + defined(PNG_LEGACY_SUPPORTED) +void PNGAPI +png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr + read_user_transform_fn) +{ + png_debug(1, "in png_set_read_user_transform_fn\n"); + if(png_ptr == NULL) return; +#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) + png_ptr->transformations |= PNG_USER_TRANSFORM; + png_ptr->read_user_transform_fn = read_user_transform_fn; +#endif +#ifdef PNG_LEGACY_SUPPORTED + if(read_user_transform_fn) + png_warning(png_ptr, + "This version of libpng does not support user transforms"); +#endif +} +#endif + +/* Initialize everything needed for the read. This includes modifying + * the palette. + */ +void /* PRIVATE */ +png_init_read_transformations(png_structp png_ptr) +{ + png_debug(1, "in png_init_read_transformations\n"); +#if defined(PNG_USELESS_TESTS_SUPPORTED) + if(png_ptr != NULL) +#endif + { +#if defined(PNG_READ_BACKGROUND_SUPPORTED) || defined(PNG_READ_SHIFT_SUPPORTED) \ + || defined(PNG_READ_GAMMA_SUPPORTED) + int color_type = png_ptr->color_type; +#endif + +#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED) + +#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) + /* Detect gray background and attempt to enable optimization + * for gray --> RGB case */ + /* Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or + * RGB_ALPHA (in which case need_expand is superfluous anyway), the + * background color might actually be gray yet not be flagged as such. + * This is not a problem for the current code, which uses + * PNG_BACKGROUND_IS_GRAY only to decide when to do the + * png_do_gray_to_rgb() transformation. + */ + if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + !(color_type & PNG_COLOR_MASK_COLOR)) + { + png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; + } else if ((png_ptr->transformations & PNG_BACKGROUND) && + !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + (png_ptr->transformations & PNG_GRAY_TO_RGB) && + png_ptr->background.red == png_ptr->background.green && + png_ptr->background.red == png_ptr->background.blue) + { + png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; + png_ptr->background.gray = png_ptr->background.red; + } +#endif + + if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + (png_ptr->transformations & PNG_EXPAND)) + { + if (!(color_type & PNG_COLOR_MASK_COLOR)) /* i.e., GRAY or GRAY_ALPHA */ + { + /* expand background and tRNS chunks */ + switch (png_ptr->bit_depth) + { + case 1: + png_ptr->background.gray *= (png_uint_16)0xff; + png_ptr->background.red = png_ptr->background.green + = png_ptr->background.blue = png_ptr->background.gray; + if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) + { + png_ptr->trans_values.gray *= (png_uint_16)0xff; + png_ptr->trans_values.red = png_ptr->trans_values.green + = png_ptr->trans_values.blue = png_ptr->trans_values.gray; + } + break; + case 2: + png_ptr->background.gray *= (png_uint_16)0x55; + png_ptr->background.red = png_ptr->background.green + = png_ptr->background.blue = png_ptr->background.gray; + if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) + { + png_ptr->trans_values.gray *= (png_uint_16)0x55; + png_ptr->trans_values.red = png_ptr->trans_values.green + = png_ptr->trans_values.blue = png_ptr->trans_values.gray; + } + break; + case 4: + png_ptr->background.gray *= (png_uint_16)0x11; + png_ptr->background.red = png_ptr->background.green + = png_ptr->background.blue = png_ptr->background.gray; + if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) + { + png_ptr->trans_values.gray *= (png_uint_16)0x11; + png_ptr->trans_values.red = png_ptr->trans_values.green + = png_ptr->trans_values.blue = png_ptr->trans_values.gray; + } + break; + case 8: + case 16: + png_ptr->background.red = png_ptr->background.green + = png_ptr->background.blue = png_ptr->background.gray; + break; + } + } + else if (color_type == PNG_COLOR_TYPE_PALETTE) + { + png_ptr->background.red = + png_ptr->palette[png_ptr->background.index].red; + png_ptr->background.green = + png_ptr->palette[png_ptr->background.index].green; + png_ptr->background.blue = + png_ptr->palette[png_ptr->background.index].blue; + +#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) + if (png_ptr->transformations & PNG_INVERT_ALPHA) + { +#if defined(PNG_READ_EXPAND_SUPPORTED) + if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) +#endif + { + /* invert the alpha channel (in tRNS) unless the pixels are + going to be expanded, in which case leave it for later */ + int i,istop; + istop=(int)png_ptr->num_trans; + for (i=0; i<istop; i++) + png_ptr->trans[i] = (png_byte)(255 - png_ptr->trans[i]); + } + } +#endif + + } + } +#endif + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED) + png_ptr->background_1 = png_ptr->background; +#endif +#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED) + + if ((color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_trans != 0) + && (fabs(png_ptr->screen_gamma * png_ptr->gamma - 1.0) + < PNG_GAMMA_THRESHOLD)) + { + int i,k; + k=0; + for (i=0; i<png_ptr->num_trans; i++) + { + if (png_ptr->trans[i] != 0 && png_ptr->trans[i] != 0xff) + k=1; /* partial transparency is present */ + } + if (k == 0) + png_ptr->transformations &= ~PNG_GAMMA; + } + + if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) && + png_ptr->gamma != 0.0) + { + png_build_gamma_table(png_ptr); +#if defined(PNG_READ_BACKGROUND_SUPPORTED) + if (png_ptr->transformations & PNG_BACKGROUND) + { + if (color_type == PNG_COLOR_TYPE_PALETTE) + { + /* could skip if no transparency and + */ + png_color back, back_1; + png_colorp palette = png_ptr->palette; + int num_palette = png_ptr->num_palette; + int i; + if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE) + { + back.red = png_ptr->gamma_table[png_ptr->background.red]; + back.green = png_ptr->gamma_table[png_ptr->background.green]; + back.blue = png_ptr->gamma_table[png_ptr->background.blue]; + + back_1.red = png_ptr->gamma_to_1[png_ptr->background.red]; + back_1.green = png_ptr->gamma_to_1[png_ptr->background.green]; + back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue]; + } + else + { + double g, gs; + + switch (png_ptr->background_gamma_type) + { + case PNG_BACKGROUND_GAMMA_SCREEN: + g = (png_ptr->screen_gamma); + gs = 1.0; + break; + case PNG_BACKGROUND_GAMMA_FILE: + g = 1.0 / (png_ptr->gamma); + gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); + break; + case PNG_BACKGROUND_GAMMA_UNIQUE: + g = 1.0 / (png_ptr->background_gamma); + gs = 1.0 / (png_ptr->background_gamma * + png_ptr->screen_gamma); + break; + default: + g = 1.0; /* back_1 */ + gs = 1.0; /* back */ + } + + if ( fabs(gs - 1.0) < PNG_GAMMA_THRESHOLD) + { + back.red = (png_byte)png_ptr->background.red; + back.green = (png_byte)png_ptr->background.green; + back.blue = (png_byte)png_ptr->background.blue; + } + else + { + back.red = (png_byte)(pow( + (double)png_ptr->background.red/255, gs) * 255.0 + .5); + back.green = (png_byte)(pow( + (double)png_ptr->background.green/255, gs) * 255.0 + .5); + back.blue = (png_byte)(pow( + (double)png_ptr->background.blue/255, gs) * 255.0 + .5); + } + + back_1.red = (png_byte)(pow( + (double)png_ptr->background.red/255, g) * 255.0 + .5); + back_1.green = (png_byte)(pow( + (double)png_ptr->background.green/255, g) * 255.0 + .5); + back_1.blue = (png_byte)(pow( + (double)png_ptr->background.blue/255, g) * 255.0 + .5); + } + for (i = 0; i < num_palette; i++) + { + if (i < (int)png_ptr->num_trans && png_ptr->trans[i] != 0xff) + { + if (png_ptr->trans[i] == 0) + { + palette[i] = back; + } + else /* if (png_ptr->trans[i] != 0xff) */ + { + png_byte v, w; + + v = png_ptr->gamma_to_1[palette[i].red]; + png_composite(w, v, png_ptr->trans[i], back_1.red); + palette[i].red = png_ptr->gamma_from_1[w]; + + v = png_ptr->gamma_to_1[palette[i].green]; + png_composite(w, v, png_ptr->trans[i], back_1.green); + palette[i].green = png_ptr->gamma_from_1[w]; + + v = png_ptr->gamma_to_1[palette[i].blue]; + png_composite(w, v, png_ptr->trans[i], back_1.blue); + palette[i].blue = png_ptr->gamma_from_1[w]; + } + } + else + { + palette[i].red = png_ptr->gamma_table[palette[i].red]; + palette[i].green = png_ptr->gamma_table[palette[i].green]; + palette[i].blue = png_ptr->gamma_table[palette[i].blue]; + } + } + /* Prevent the transformations being done again, and make sure + * that the now spurious alpha channel is stripped - the code + * has just reduced background composition and gamma correction + * to a simple alpha channel strip. + */ + png_ptr->transformations &= ~PNG_BACKGROUND; + png_ptr->transformations &= ~PNG_GAMMA; + png_ptr->transformations |= PNG_STRIP_ALPHA; + } + /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */ + else + /* color_type != PNG_COLOR_TYPE_PALETTE */ + { + double m = (double)(((png_uint_32)1 << png_ptr->bit_depth) - 1); + double g = 1.0; + double gs = 1.0; + + switch (png_ptr->background_gamma_type) + { + case PNG_BACKGROUND_GAMMA_SCREEN: + g = (png_ptr->screen_gamma); + gs = 1.0; + break; + case PNG_BACKGROUND_GAMMA_FILE: + g = 1.0 / (png_ptr->gamma); + gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); + break; + case PNG_BACKGROUND_GAMMA_UNIQUE: + g = 1.0 / (png_ptr->background_gamma); + gs = 1.0 / (png_ptr->background_gamma * + png_ptr->screen_gamma); + break; + } + + png_ptr->background_1.gray = (png_uint_16)(pow( + (double)png_ptr->background.gray / m, g) * m + .5); + png_ptr->background.gray = (png_uint_16)(pow( + (double)png_ptr->background.gray / m, gs) * m + .5); + + if ((png_ptr->background.red != png_ptr->background.green) || + (png_ptr->background.red != png_ptr->background.blue) || + (png_ptr->background.red != png_ptr->background.gray)) + { + /* RGB or RGBA with color background */ + png_ptr->background_1.red = (png_uint_16)(pow( + (double)png_ptr->background.red / m, g) * m + .5); + png_ptr->background_1.green = (png_uint_16)(pow( + (double)png_ptr->background.green / m, g) * m + .5); + png_ptr->background_1.blue = (png_uint_16)(pow( + (double)png_ptr->background.blue / m, g) * m + .5); + png_ptr->background.red = (png_uint_16)(pow( + (double)png_ptr->background.red / m, gs) * m + .5); + png_ptr->background.green = (png_uint_16)(pow( + (double)png_ptr->background.green / m, gs) * m + .5); + png_ptr->background.blue = (png_uint_16)(pow( + (double)png_ptr->background.blue / m, gs) * m + .5); + } + else + { + /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */ + png_ptr->background_1.red = png_ptr->background_1.green + = png_ptr->background_1.blue = png_ptr->background_1.gray; + png_ptr->background.red = png_ptr->background.green + = png_ptr->background.blue = png_ptr->background.gray; + } + } + } + else + /* transformation does not include PNG_BACKGROUND */ +#endif /* PNG_READ_BACKGROUND_SUPPORTED */ + if (color_type == PNG_COLOR_TYPE_PALETTE) + { + png_colorp palette = png_ptr->palette; + int num_palette = png_ptr->num_palette; + int i; + + for (i = 0; i < num_palette; i++) + { + palette[i].red = png_ptr->gamma_table[palette[i].red]; + palette[i].green = png_ptr->gamma_table[palette[i].green]; + palette[i].blue = png_ptr->gamma_table[palette[i].blue]; + } + + /* Done the gamma correction. */ + png_ptr->transformations &= ~PNG_GAMMA; + } + } +#if defined(PNG_READ_BACKGROUND_SUPPORTED) + else +#endif +#endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */ +#if defined(PNG_READ_BACKGROUND_SUPPORTED) + /* No GAMMA transformation */ + if ((png_ptr->transformations & PNG_BACKGROUND) && + (color_type == PNG_COLOR_TYPE_PALETTE)) + { + int i; + int istop = (int)png_ptr->num_trans; + png_color back; + png_colorp palette = png_ptr->palette; + + back.red = (png_byte)png_ptr->background.red; + back.green = (png_byte)png_ptr->background.green; + back.blue = (png_byte)png_ptr->background.blue; + + for (i = 0; i < istop; i++) + { + if (png_ptr->trans[i] == 0) + { + palette[i] = back; + } + else if (png_ptr->trans[i] != 0xff) + { + /* The png_composite() macro is defined in png.h */ + png_composite(palette[i].red, palette[i].red, + png_ptr->trans[i], back.red); + png_composite(palette[i].green, palette[i].green, + png_ptr->trans[i], back.green); + png_composite(palette[i].blue, palette[i].blue, + png_ptr->trans[i], back.blue); + } + } + + /* Handled alpha, still need to strip the channel. */ + png_ptr->transformations &= ~PNG_BACKGROUND; + png_ptr->transformations |= PNG_STRIP_ALPHA; + } +#endif /* PNG_READ_BACKGROUND_SUPPORTED */ + +#if defined(PNG_READ_SHIFT_SUPPORTED) + if ((png_ptr->transformations & PNG_SHIFT) && + (color_type == PNG_COLOR_TYPE_PALETTE)) + { + png_uint_16 i; + png_uint_16 istop = png_ptr->num_palette; + int sr = 8 - png_ptr->sig_bit.red; + int sg = 8 - png_ptr->sig_bit.green; + int sb = 8 - png_ptr->sig_bit.blue; + + if (sr < 0 || sr > 8) + sr = 0; + if (sg < 0 || sg > 8) + sg = 0; + if (sb < 0 || sb > 8) + sb = 0; + for (i = 0; i < istop; i++) + { + png_ptr->palette[i].red >>= sr; + png_ptr->palette[i].green >>= sg; + png_ptr->palette[i].blue >>= sb; + } + } +#endif /* PNG_READ_SHIFT_SUPPORTED */ + } +#if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \ + && !defined(PNG_READ_BACKGROUND_SUPPORTED) + if(png_ptr) + return; +#endif +} + +/* Modify the info structure to reflect the transformations. The + * info should be updated so a PNG file could be written with it, + * assuming the transformations result in valid PNG data. + */ +void /* PRIVATE */ +png_read_transform_info(png_structp png_ptr, png_infop info_ptr) +{ + png_debug(1, "in png_read_transform_info\n"); +#if defined(PNG_READ_EXPAND_SUPPORTED) + if (png_ptr->transformations & PNG_EXPAND) + { + if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (png_ptr->num_trans && + (png_ptr->transformations & PNG_EXPAND_tRNS)) + info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA; + else + info_ptr->color_type = PNG_COLOR_TYPE_RGB; + info_ptr->bit_depth = 8; + info_ptr->num_trans = 0; + } + else + { + if (png_ptr->num_trans) + { + if (png_ptr->transformations & PNG_EXPAND_tRNS) + info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; +#if 0 /* Removed from libpng-1.2.27 */ + else + info_ptr->color_type |= PNG_COLOR_MASK_COLOR; +#endif + } + if (info_ptr->bit_depth < 8) + info_ptr->bit_depth = 8; + info_ptr->num_trans = 0; + } + } +#endif + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) + if (png_ptr->transformations & PNG_BACKGROUND) + { + info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA; + info_ptr->num_trans = 0; + info_ptr->background = png_ptr->background; + } +#endif + +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (png_ptr->transformations & PNG_GAMMA) + { +#ifdef PNG_FLOATING_POINT_SUPPORTED + info_ptr->gamma = png_ptr->gamma; +#endif +#ifdef PNG_FIXED_POINT_SUPPORTED + info_ptr->int_gamma = png_ptr->int_gamma; +#endif + } +#endif + +#if defined(PNG_READ_16_TO_8_SUPPORTED) + if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16)) + info_ptr->bit_depth = 8; +#endif + +#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) + if (png_ptr->transformations & PNG_GRAY_TO_RGB) + info_ptr->color_type |= PNG_COLOR_MASK_COLOR; +#endif + +#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) + if (png_ptr->transformations & PNG_RGB_TO_GRAY) + info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR; +#endif + +#if defined(PNG_READ_DITHER_SUPPORTED) + if (png_ptr->transformations & PNG_DITHER) + { + if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) || + (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) && + png_ptr->palette_lookup && info_ptr->bit_depth == 8) + { + info_ptr->color_type = PNG_COLOR_TYPE_PALETTE; + } + } +#endif + +#if defined(PNG_READ_PACK_SUPPORTED) + if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8)) + info_ptr->bit_depth = 8; +#endif + + if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + info_ptr->channels = 1; + else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR) + info_ptr->channels = 3; + else + info_ptr->channels = 1; + +#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED) + if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA) + info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA; +#endif + + if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA) + info_ptr->channels++; + +#if defined(PNG_READ_FILLER_SUPPORTED) + /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */ + if ((png_ptr->transformations & PNG_FILLER) && + ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) || + (info_ptr->color_type == PNG_COLOR_TYPE_GRAY))) + { + info_ptr->channels++; + /* if adding a true alpha channel not just filler */ +#if !defined(PNG_1_0_X) + if (png_ptr->transformations & PNG_ADD_ALPHA) + info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; +#endif + } +#endif + +#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \ +defined(PNG_READ_USER_TRANSFORM_SUPPORTED) + if(png_ptr->transformations & PNG_USER_TRANSFORM) + { + if(info_ptr->bit_depth < png_ptr->user_transform_depth) + info_ptr->bit_depth = png_ptr->user_transform_depth; + if(info_ptr->channels < png_ptr->user_transform_channels) + info_ptr->channels = png_ptr->user_transform_channels; + } +#endif + + info_ptr->pixel_depth = (png_byte)(info_ptr->channels * + info_ptr->bit_depth); + + info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth,info_ptr->width); + +#if !defined(PNG_READ_EXPAND_SUPPORTED) + if(png_ptr) + return; +#endif +} + +/* Transform the row. The order of transformations is significant, + * and is very touchy. If you add a transformation, take care to + * decide how it fits in with the other transformations here. + */ +void /* PRIVATE */ +png_do_read_transformations(png_structp png_ptr) +{ + png_debug(1, "in png_do_read_transformations\n"); + if (png_ptr->row_buf == NULL) + { +#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE) + char msg[50]; + + png_snprintf2(msg, 50, + "NULL row buffer for row %ld, pass %d", png_ptr->row_number, + png_ptr->pass); + png_error(png_ptr, msg); +#else + png_error(png_ptr, "NULL row buffer"); +#endif + } +#ifdef PNG_WARN_UNINITIALIZED_ROW + if (!(png_ptr->flags & PNG_FLAG_ROW_INIT)) + /* Application has failed to call either png_read_start_image() + * or png_read_update_info() after setting transforms that expand + * pixels. This check added to libpng-1.2.19 */ +#if (PNG_WARN_UNINITIALIZED_ROW==1) + png_error(png_ptr, "Uninitialized row"); +#else + png_warning(png_ptr, "Uninitialized row"); +#endif +#endif + +#if defined(PNG_READ_EXPAND_SUPPORTED) + if (png_ptr->transformations & PNG_EXPAND) + { + if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE) + { + png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1, + png_ptr->palette, png_ptr->trans, png_ptr->num_trans); + } + else + { + if (png_ptr->num_trans && + (png_ptr->transformations & PNG_EXPAND_tRNS)) + png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, + &(png_ptr->trans_values)); + else + png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, + NULL); + } + } +#endif + +#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED) + if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA) + png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, + PNG_FLAG_FILLER_AFTER | (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)); +#endif + +#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) + if (png_ptr->transformations & PNG_RGB_TO_GRAY) + { + int rgb_error = + png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info), png_ptr->row_buf + 1); + if(rgb_error) + { + png_ptr->rgb_to_gray_status=1; + if((png_ptr->transformations & PNG_RGB_TO_GRAY) == + PNG_RGB_TO_GRAY_WARN) + png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel"); + if((png_ptr->transformations & PNG_RGB_TO_GRAY) == + PNG_RGB_TO_GRAY_ERR) + png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel"); + } + } +#endif + +/* +From Andreas Dilger e-mail to png-implement, 26 March 1998: + + In most cases, the "simple transparency" should be done prior to doing + gray-to-RGB, or you will have to test 3x as many bytes to check if a + pixel is transparent. You would also need to make sure that the + transparency information is upgraded to RGB. + + To summarize, the current flow is: + - Gray + simple transparency -> compare 1 or 2 gray bytes and composite + with background "in place" if transparent, + convert to RGB if necessary + - Gray + alpha -> composite with gray background and remove alpha bytes, + convert to RGB if necessary + + To support RGB backgrounds for gray images we need: + - Gray + simple transparency -> convert to RGB + simple transparency, compare + 3 or 6 bytes and composite with background + "in place" if transparent (3x compare/pixel + compared to doing composite with gray bkgrnd) + - Gray + alpha -> convert to RGB + alpha, composite with background and + remove alpha bytes (3x float operations/pixel + compared with composite on gray background) + + Greg's change will do this. The reason it wasn't done before is for + performance, as this increases the per-pixel operations. If we would check + in advance if the background was gray or RGB, and position the gray-to-RGB + transform appropriately, then it would save a lot of work/time. + */ + +#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) + /* if gray -> RGB, do so now only if background is non-gray; else do later + * for performance reasons */ + if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && + !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) + png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) + if ((png_ptr->transformations & PNG_BACKGROUND) && + ((png_ptr->num_trans != 0 ) || + (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) + png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1, + &(png_ptr->trans_values), &(png_ptr->background) +#if defined(PNG_READ_GAMMA_SUPPORTED) + , &(png_ptr->background_1), + png_ptr->gamma_table, png_ptr->gamma_from_1, + png_ptr->gamma_to_1, png_ptr->gamma_16_table, + png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1, + png_ptr->gamma_shift +#endif +); +#endif + +#if defined(PNG_READ_GAMMA_SUPPORTED) + if ((png_ptr->transformations & PNG_GAMMA) && +#if defined(PNG_READ_BACKGROUND_SUPPORTED) + !((png_ptr->transformations & PNG_BACKGROUND) && + ((png_ptr->num_trans != 0) || + (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) && +#endif + (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)) + png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1, + png_ptr->gamma_table, png_ptr->gamma_16_table, + png_ptr->gamma_shift); +#endif + +#if defined(PNG_READ_16_TO_8_SUPPORTED) + if (png_ptr->transformations & PNG_16_TO_8) + png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_DITHER_SUPPORTED) + if (png_ptr->transformations & PNG_DITHER) + { + png_do_dither((png_row_infop)&(png_ptr->row_info), png_ptr->row_buf + 1, + png_ptr->palette_lookup, png_ptr->dither_index); + if(png_ptr->row_info.rowbytes == (png_uint_32)0) + png_error(png_ptr, "png_do_dither returned rowbytes=0"); + } +#endif + +#if defined(PNG_READ_INVERT_SUPPORTED) + if (png_ptr->transformations & PNG_INVERT_MONO) + png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_SHIFT_SUPPORTED) + if (png_ptr->transformations & PNG_SHIFT) + png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1, + &(png_ptr->shift)); +#endif + +#if defined(PNG_READ_PACK_SUPPORTED) + if (png_ptr->transformations & PNG_PACK) + png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_BGR_SUPPORTED) + if (png_ptr->transformations & PNG_BGR) + png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_PACKSWAP_SUPPORTED) + if (png_ptr->transformations & PNG_PACKSWAP) + png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) + /* if gray -> RGB, do so now only if we did not do so above */ + if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && + (png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) + png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_FILLER_SUPPORTED) + if (png_ptr->transformations & PNG_FILLER) + png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, + (png_uint_32)png_ptr->filler, png_ptr->flags); +#endif + +#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) + if (png_ptr->transformations & PNG_INVERT_ALPHA) + png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) + if (png_ptr->transformations & PNG_SWAP_ALPHA) + png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_SWAP_SUPPORTED) + if (png_ptr->transformations & PNG_SWAP_BYTES) + png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) + if (png_ptr->transformations & PNG_USER_TRANSFORM) + { + if(png_ptr->read_user_transform_fn != NULL) + (*(png_ptr->read_user_transform_fn)) /* user read transform function */ + (png_ptr, /* png_ptr */ + &(png_ptr->row_info), /* row_info: */ + /* png_uint_32 width; width of row */ + /* png_uint_32 rowbytes; number of bytes in row */ + /* png_byte color_type; color type of pixels */ + /* png_byte bit_depth; bit depth of samples */ + /* png_byte channels; number of channels (1-4) */ + /* png_byte pixel_depth; bits per pixel (depth*channels) */ + png_ptr->row_buf + 1); /* start of pixel data for row */ +#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) + if(png_ptr->user_transform_depth) + png_ptr->row_info.bit_depth = png_ptr->user_transform_depth; + if(png_ptr->user_transform_channels) + png_ptr->row_info.channels = png_ptr->user_transform_channels; +#endif + png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth * + png_ptr->row_info.channels); + png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth, + png_ptr->row_info.width); + } +#endif + +} + +#if defined(PNG_READ_PACK_SUPPORTED) +/* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel, + * without changing the actual values. Thus, if you had a row with + * a bit depth of 1, you would end up with bytes that only contained + * the numbers 0 or 1. If you would rather they contain 0 and 255, use + * png_do_shift() after this. + */ +void /* PRIVATE */ +png_do_unpack(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_unpack\n"); +#if defined(PNG_USELESS_TESTS_SUPPORTED) + if (row != NULL && row_info != NULL && row_info->bit_depth < 8) +#else + if (row_info->bit_depth < 8) +#endif + { + png_uint_32 i; + png_uint_32 row_width=row_info->width; + + switch (row_info->bit_depth) + { + case 1: + { + png_bytep sp = row + (png_size_t)((row_width - 1) >> 3); + png_bytep dp = row + (png_size_t)row_width - 1; + png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07); + for (i = 0; i < row_width; i++) + { + *dp = (png_byte)((*sp >> shift) & 0x01); + if (shift == 7) + { + shift = 0; + sp--; + } + else + shift++; + + dp--; + } + break; + } + case 2: + { + + png_bytep sp = row + (png_size_t)((row_width - 1) >> 2); + png_bytep dp = row + (png_size_t)row_width - 1; + png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1); + for (i = 0; i < row_width; i++) + { + *dp = (png_byte)((*sp >> shift) & 0x03); + if (shift == 6) + { + shift = 0; + sp--; + } + else + shift += 2; + + dp--; + } + break; + } + case 4: + { + png_bytep sp = row + (png_size_t)((row_width - 1) >> 1); + png_bytep dp = row + (png_size_t)row_width - 1; + png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2); + for (i = 0; i < row_width; i++) + { + *dp = (png_byte)((*sp >> shift) & 0x0f); + if (shift == 4) + { + shift = 0; + sp--; + } + else + shift = 4; + + dp--; + } + break; + } + } + row_info->bit_depth = 8; + row_info->pixel_depth = (png_byte)(8 * row_info->channels); + row_info->rowbytes = row_width * row_info->channels; + } +} +#endif + +#if defined(PNG_READ_SHIFT_SUPPORTED) +/* Reverse the effects of png_do_shift. This routine merely shifts the + * pixels back to their significant bits values. Thus, if you have + * a row of bit depth 8, but only 5 are significant, this will shift + * the values back to 0 through 31. + */ +void /* PRIVATE */ +png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) +{ + png_debug(1, "in png_do_unshift\n"); + if ( +#if defined(PNG_USELESS_TESTS_SUPPORTED) + row != NULL && row_info != NULL && sig_bits != NULL && +#endif + row_info->color_type != PNG_COLOR_TYPE_PALETTE) + { + int shift[4]; + int channels = 0; + int c; + png_uint_16 value = 0; + png_uint_32 row_width = row_info->width; + + if (row_info->color_type & PNG_COLOR_MASK_COLOR) + { + shift[channels++] = row_info->bit_depth - sig_bits->red; + shift[channels++] = row_info->bit_depth - sig_bits->green; + shift[channels++] = row_info->bit_depth - sig_bits->blue; + } + else + { + shift[channels++] = row_info->bit_depth - sig_bits->gray; + } + if (row_info->color_type & PNG_COLOR_MASK_ALPHA) + { + shift[channels++] = row_info->bit_depth - sig_bits->alpha; + } + + for (c = 0; c < channels; c++) + { + if (shift[c] <= 0) + shift[c] = 0; + else + value = 1; + } + + if (!value) + return; + + switch (row_info->bit_depth) + { + case 2: + { + png_bytep bp; + png_uint_32 i; + png_uint_32 istop = row_info->rowbytes; + + for (bp = row, i = 0; i < istop; i++) + { + *bp >>= 1; + *bp++ &= 0x55; + } + break; + } + case 4: + { + png_bytep bp = row; + png_uint_32 i; + png_uint_32 istop = row_info->rowbytes; + png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) | + (png_byte)((int)0xf >> shift[0])); + + for (i = 0; i < istop; i++) + { + *bp >>= shift[0]; + *bp++ &= mask; + } + break; + } + case 8: + { + png_bytep bp = row; + png_uint_32 i; + png_uint_32 istop = row_width * channels; + + for (i = 0; i < istop; i++) + { + *bp++ >>= shift[i%channels]; + } + break; + } + case 16: + { + png_bytep bp = row; + png_uint_32 i; + png_uint_32 istop = channels * row_width; + + for (i = 0; i < istop; i++) + { + value = (png_uint_16)((*bp << 8) + *(bp + 1)); + value >>= shift[i%channels]; + *bp++ = (png_byte)(value >> 8); + *bp++ = (png_byte)(value & 0xff); + } + break; + } + } + } +} +#endif + +#if defined(PNG_READ_16_TO_8_SUPPORTED) +/* chop rows of bit depth 16 down to 8 */ +void /* PRIVATE */ +png_do_chop(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_chop\n"); +#if defined(PNG_USELESS_TESTS_SUPPORTED) + if (row != NULL && row_info != NULL && row_info->bit_depth == 16) +#else + if (row_info->bit_depth == 16) +#endif + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; + png_uint_32 istop = row_info->width * row_info->channels; + + for (i = 0; i<istop; i++, sp += 2, dp++) + { +#if defined(PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED) + /* This does a more accurate scaling of the 16-bit color + * value, rather than a simple low-byte truncation. + * + * What the ideal calculation should be: + * *dp = (((((png_uint_32)(*sp) << 8) | + * (png_uint_32)(*(sp + 1))) * 255 + 127) / (png_uint_32)65535L; + * + * GRR: no, I think this is what it really should be: + * *dp = (((((png_uint_32)(*sp) << 8) | + * (png_uint_32)(*(sp + 1))) + 128L) / (png_uint_32)257L; + * + * GRR: here's the exact calculation with shifts: + * temp = (((png_uint_32)(*sp) << 8) | (png_uint_32)(*(sp + 1))) + 128L; + * *dp = (temp - (temp >> 8)) >> 8; + * + * Approximate calculation with shift/add instead of multiply/divide: + * *dp = ((((png_uint_32)(*sp) << 8) | + * (png_uint_32)((int)(*(sp + 1)) - *sp)) + 128) >> 8; + * + * What we actually do to avoid extra shifting and conversion: + */ + + *dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0); +#else + /* Simply discard the low order byte */ + *dp = *sp; +#endif + } + row_info->bit_depth = 8; + row_info->pixel_depth = (png_byte)(8 * row_info->channels); + row_info->rowbytes = row_info->width * row_info->channels; + } +} +#endif + +#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) +void /* PRIVATE */ +png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_read_swap_alpha\n"); +#if defined(PNG_USELESS_TESTS_SUPPORTED) + if (row != NULL && row_info != NULL) +#endif + { + png_uint_32 row_width = row_info->width; + if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + { + /* This converts from RGBA to ARGB */ + if (row_info->bit_depth == 8) + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_byte save; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + save = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = save; + } + } + /* This converts from RRGGBBAA to AARRGGBB */ + else + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_byte save[2]; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + save[0] = *(--sp); + save[1] = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = save[0]; + *(--dp) = save[1]; + } + } + } + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + /* This converts from GA to AG */ + if (row_info->bit_depth == 8) + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_byte save; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + save = *(--sp); + *(--dp) = *(--sp); + *(--dp) = save; + } + } + /* This converts from GGAA to AAGG */ + else + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_byte save[2]; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + save[0] = *(--sp); + save[1] = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = save[0]; + *(--dp) = save[1]; + } + } + } + } +} +#endif + +#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) +void /* PRIVATE */ +png_do_read_invert_alpha(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_read_invert_alpha\n"); +#if defined(PNG_USELESS_TESTS_SUPPORTED) + if (row != NULL && row_info != NULL) +#endif + { + png_uint_32 row_width = row_info->width; + if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + { + /* This inverts the alpha channel in RGBA */ + if (row_info->bit_depth == 8) + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + *(--dp) = (png_byte)(255 - *(--sp)); + +/* This does nothing: + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + We can replace it with: +*/ + sp-=3; + dp=sp; + } + } + /* This inverts the alpha channel in RRGGBBAA */ + else + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + *(--dp) = (png_byte)(255 - *(--sp)); + *(--dp) = (png_byte)(255 - *(--sp)); + +/* This does nothing: + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + We can replace it with: +*/ + sp-=6; + dp=sp; + } + } + } + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + /* This inverts the alpha channel in GA */ + if (row_info->bit_depth == 8) + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + *(--dp) = (png_byte)(255 - *(--sp)); + *(--dp) = *(--sp); + } + } + /* This inverts the alpha channel in GGAA */ + else + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + *(--dp) = (png_byte)(255 - *(--sp)); + *(--dp) = (png_byte)(255 - *(--sp)); +/* + *(--dp) = *(--sp); + *(--dp) = *(--sp); +*/ + sp-=2; + dp=sp; + } + } + } + } +} +#endif + +#if defined(PNG_READ_FILLER_SUPPORTED) +/* Add filler channel if we have RGB color */ +void /* PRIVATE */ +png_do_read_filler(png_row_infop row_info, png_bytep row, + png_uint_32 filler, png_uint_32 flags) +{ + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + png_byte hi_filler = (png_byte)((filler>>8) & 0xff); + png_byte lo_filler = (png_byte)(filler & 0xff); + + png_debug(1, "in png_do_read_filler\n"); + if ( +#if defined(PNG_USELESS_TESTS_SUPPORTED) + row != NULL && row_info != NULL && +#endif + row_info->color_type == PNG_COLOR_TYPE_GRAY) + { + if(row_info->bit_depth == 8) + { + /* This changes the data from G to GX */ + if (flags & PNG_FLAG_FILLER_AFTER) + { + png_bytep sp = row + (png_size_t)row_width; + png_bytep dp = sp + (png_size_t)row_width; + for (i = 1; i < row_width; i++) + { + *(--dp) = lo_filler; + *(--dp) = *(--sp); + } + *(--dp) = lo_filler; + row_info->channels = 2; + row_info->pixel_depth = 16; + row_info->rowbytes = row_width * 2; + } + /* This changes the data from G to XG */ + else + { + png_bytep sp = row + (png_size_t)row_width; + png_bytep dp = sp + (png_size_t)row_width; + for (i = 0; i < row_width; i++) + { + *(--dp) = *(--sp); + *(--dp) = lo_filler; + } + row_info->channels = 2; + row_info->pixel_depth = 16; + row_info->rowbytes = row_width * 2; + } + } + else if(row_info->bit_depth == 16) + { + /* This changes the data from GG to GGXX */ + if (flags & PNG_FLAG_FILLER_AFTER) + { + png_bytep sp = row + (png_size_t)row_width * 2; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 1; i < row_width; i++) + { + *(--dp) = hi_filler; + *(--dp) = lo_filler; + *(--dp) = *(--sp); + *(--dp) = *(--sp); + } + *(--dp) = hi_filler; + *(--dp) = lo_filler; + row_info->channels = 2; + row_info->pixel_depth = 32; + row_info->rowbytes = row_width * 4; + } + /* This changes the data from GG to XXGG */ + else + { + png_bytep sp = row + (png_size_t)row_width * 2; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 0; i < row_width; i++) + { + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = hi_filler; + *(--dp) = lo_filler; + } + row_info->channels = 2; + row_info->pixel_depth = 32; + row_info->rowbytes = row_width * 4; + } + } + } /* COLOR_TYPE == GRAY */ + else if (row_info->color_type == PNG_COLOR_TYPE_RGB) + { + if(row_info->bit_depth == 8) + { + /* This changes the data from RGB to RGBX */ + if (flags & PNG_FLAG_FILLER_AFTER) + { + png_bytep sp = row + (png_size_t)row_width * 3; + png_bytep dp = sp + (png_size_t)row_width; + for (i = 1; i < row_width; i++) + { + *(--dp) = lo_filler; + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + } + *(--dp) = lo_filler; + row_info->channels = 4; + row_info->pixel_depth = 32; + row_info->rowbytes = row_width * 4; + } + /* This changes the data from RGB to XRGB */ + else + { + png_bytep sp = row + (png_size_t)row_width * 3; + png_bytep dp = sp + (png_size_t)row_width; + for (i = 0; i < row_width; i++) + { + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = lo_filler; + } + row_info->channels = 4; + row_info->pixel_depth = 32; + row_info->rowbytes = row_width * 4; + } + } + else if(row_info->bit_depth == 16) + { + /* This changes the data from RRGGBB to RRGGBBXX */ + if (flags & PNG_FLAG_FILLER_AFTER) + { + png_bytep sp = row + (png_size_t)row_width * 6; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 1; i < row_width; i++) + { + *(--dp) = hi_filler; + *(--dp) = lo_filler; + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + } + *(--dp) = hi_filler; + *(--dp) = lo_filler; + row_info->channels = 4; + row_info->pixel_depth = 64; + row_info->rowbytes = row_width * 8; + } + /* This changes the data from RRGGBB to XXRRGGBB */ + else + { + png_bytep sp = row + (png_size_t)row_width * 6; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 0; i < row_width; i++) + { + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = hi_filler; + *(--dp) = lo_filler; + } + row_info->channels = 4; + row_info->pixel_depth = 64; + row_info->rowbytes = row_width * 8; + } + } + } /* COLOR_TYPE == RGB */ +} +#endif + +#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) +/* expand grayscale files to RGB, with or without alpha */ +void /* PRIVATE */ +png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) +{ + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + png_debug(1, "in png_do_gray_to_rgb\n"); + if (row_info->bit_depth >= 8 && +#if defined(PNG_USELESS_TESTS_SUPPORTED) + row != NULL && row_info != NULL && +#endif + !(row_info->color_type & PNG_COLOR_MASK_COLOR)) + { + if (row_info->color_type == PNG_COLOR_TYPE_GRAY) + { + if (row_info->bit_depth == 8) + { + png_bytep sp = row + (png_size_t)row_width - 1; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 0; i < row_width; i++) + { + *(dp--) = *sp; + *(dp--) = *sp; + *(dp--) = *(sp--); + } + } + else + { + png_bytep sp = row + (png_size_t)row_width * 2 - 1; + png_bytep dp = sp + (png_size_t)row_width * 4; + for (i = 0; i < row_width; i++) + { + *(dp--) = *sp; + *(dp--) = *(sp - 1); + *(dp--) = *sp; + *(dp--) = *(sp - 1); + *(dp--) = *(sp--); + *(dp--) = *(sp--); + } + } + } + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + if (row_info->bit_depth == 8) + { + png_bytep sp = row + (png_size_t)row_width * 2 - 1; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 0; i < row_width; i++) + { + *(dp--) = *(sp--); + *(dp--) = *sp; + *(dp--) = *sp; + *(dp--) = *(sp--); + } + } + else + { + png_bytep sp = row + (png_size_t)row_width * 4 - 1; + png_bytep dp = sp + (png_size_t)row_width * 4; + for (i = 0; i < row_width; i++) + { + *(dp--) = *(sp--); + *(dp--) = *(sp--); + *(dp--) = *sp; + *(dp--) = *(sp - 1); + *(dp--) = *sp; + *(dp--) = *(sp - 1); + *(dp--) = *(sp--); + *(dp--) = *(sp--); + } + } + } + row_info->channels += (png_byte)2; + row_info->color_type |= PNG_COLOR_MASK_COLOR; + row_info->pixel_depth = (png_byte)(row_info->channels * + row_info->bit_depth); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width); + } +} +#endif + +#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) +/* reduce RGB files to grayscale, with or without alpha + * using the equation given in Poynton's ColorFAQ at + * <http://www.inforamp.net/~poynton/> + * Copyright (c) 1998-01-04 Charles Poynton poynton at inforamp.net + * + * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B + * + * We approximate this with + * + * Y = 0.21268 * R + 0.7151 * G + 0.07217 * B + * + * which can be expressed with integers as + * + * Y = (6969 * R + 23434 * G + 2365 * B)/32768 + * + * The calculation is to be done in a linear colorspace. + * + * Other integer coefficents can be used via png_set_rgb_to_gray(). + */ +int /* PRIVATE */ +png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) + +{ + png_uint_32 i; + + png_uint_32 row_width = row_info->width; + int rgb_error = 0; + + png_debug(1, "in png_do_rgb_to_gray\n"); + if ( +#if defined(PNG_USELESS_TESTS_SUPPORTED) + row != NULL && row_info != NULL && +#endif + (row_info->color_type & PNG_COLOR_MASK_COLOR)) + { + png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff; + png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff; + png_uint_32 bc = png_ptr->rgb_to_gray_blue_coeff; + + if (row_info->color_type == PNG_COLOR_TYPE_RGB) + { + if (row_info->bit_depth == 8) + { +#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) + if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL) + { + png_bytep sp = row; + png_bytep dp = row; + + for (i = 0; i < row_width; i++) + { + png_byte red = png_ptr->gamma_to_1[*(sp++)]; + png_byte green = png_ptr->gamma_to_1[*(sp++)]; + png_byte blue = png_ptr->gamma_to_1[*(sp++)]; + if(red != green || red != blue) + { + rgb_error |= 1; + *(dp++) = png_ptr->gamma_from_1[ + (rc*red+gc*green+bc*blue)>>15]; + } + else + *(dp++) = *(sp-1); + } + } + else +#endif + { + png_bytep sp = row; + png_bytep dp = row; + for (i = 0; i < row_width; i++) + { + png_byte red = *(sp++); + png_byte green = *(sp++); + png_byte blue = *(sp++); + if(red != green || red != blue) + { + rgb_error |= 1; + *(dp++) = (png_byte)((rc*red+gc*green+bc*blue)>>15); + } + else + *(dp++) = *(sp-1); + } + } + } + + else /* RGB bit_depth == 16 */ + { +#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) + if (png_ptr->gamma_16_to_1 != NULL && + png_ptr->gamma_16_from_1 != NULL) + { + png_bytep sp = row; + png_bytep dp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 red, green, blue, w; + + red = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; + green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; + blue = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; + + if(red == green && red == blue) + w = red; + else + { + png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >> + png_ptr->gamma_shift][red>>8]; + png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >> + png_ptr->gamma_shift][green>>8]; + png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >> + png_ptr->gamma_shift][blue>>8]; + png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1 + + bc*blue_1)>>15); + w = png_ptr->gamma_16_from_1[(gray16&0xff) >> + png_ptr->gamma_shift][gray16 >> 8]; + rgb_error |= 1; + } + + *(dp++) = (png_byte)((w>>8) & 0xff); + *(dp++) = (png_byte)(w & 0xff); + } + } + else +#endif + { + png_bytep sp = row; + png_bytep dp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 red, green, blue, gray16; + + red = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; + green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; + blue = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; + + if(red != green || red != blue) + rgb_error |= 1; + gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15); + *(dp++) = (png_byte)((gray16>>8) & 0xff); + *(dp++) = (png_byte)(gray16 & 0xff); + } + } + } + } + if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + { + if (row_info->bit_depth == 8) + { +#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) + if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL) + { + png_bytep sp = row; + png_bytep dp = row; + for (i = 0; i < row_width; i++) + { + png_byte red = png_ptr->gamma_to_1[*(sp++)]; + png_byte green = png_ptr->gamma_to_1[*(sp++)]; + png_byte blue = png_ptr->gamma_to_1[*(sp++)]; + if(red != green || red != blue) + rgb_error |= 1; + *(dp++) = png_ptr->gamma_from_1 + [(rc*red + gc*green + bc*blue)>>15]; + *(dp++) = *(sp++); /* alpha */ + } + } + else +#endif + { + png_bytep sp = row; + png_bytep dp = row; + for (i = 0; i < row_width; i++) + { + png_byte red = *(sp++); + png_byte green = *(sp++); + png_byte blue = *(sp++); + if(red != green || red != blue) + rgb_error |= 1; + *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15); + *(dp++) = *(sp++); /* alpha */ + } + } + } + else /* RGBA bit_depth == 16 */ + { +#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) + if (png_ptr->gamma_16_to_1 != NULL && + png_ptr->gamma_16_from_1 != NULL) + { + png_bytep sp = row; + png_bytep dp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 red, green, blue, w; + + red = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; + green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; + blue = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; + + if(red == green && red == blue) + w = red; + else + { + png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >> + png_ptr->gamma_shift][red>>8]; + png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >> + png_ptr->gamma_shift][green>>8]; + png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >> + png_ptr->gamma_shift][blue>>8]; + png_uint_16 gray16 = (png_uint_16)((rc * red_1 + + gc * green_1 + bc * blue_1)>>15); + w = png_ptr->gamma_16_from_1[(gray16&0xff) >> + png_ptr->gamma_shift][gray16 >> 8]; + rgb_error |= 1; + } + + *(dp++) = (png_byte)((w>>8) & 0xff); + *(dp++) = (png_byte)(w & 0xff); + *(dp++) = *(sp++); /* alpha */ + *(dp++) = *(sp++); + } + } + else +#endif + { + png_bytep sp = row; + png_bytep dp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 red, green, blue, gray16; + red = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2; + green = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2; + blue = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2; + if(red != green || red != blue) + rgb_error |= 1; + gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15); + *(dp++) = (png_byte)((gray16>>8) & 0xff); + *(dp++) = (png_byte)(gray16 & 0xff); + *(dp++) = *(sp++); /* alpha */ + *(dp++) = *(sp++); + } + } + } + } + row_info->channels -= (png_byte)2; + row_info->color_type &= ~PNG_COLOR_MASK_COLOR; + row_info->pixel_depth = (png_byte)(row_info->channels * + row_info->bit_depth); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width); + } + return rgb_error; +} +#endif + +/* Build a grayscale palette. Palette is assumed to be 1 << bit_depth + * large of png_color. This lets grayscale images be treated as + * paletted. Most useful for gamma correction and simplification + * of code. + */ +void PNGAPI +png_build_grayscale_palette(int bit_depth, png_colorp palette) +{ + int num_palette; + int color_inc; + int i; + int v; + + png_debug(1, "in png_do_build_grayscale_palette\n"); + if (palette == NULL) + return; + + switch (bit_depth) + { + case 1: + num_palette = 2; + color_inc = 0xff; + break; + case 2: + num_palette = 4; + color_inc = 0x55; + break; + case 4: + num_palette = 16; + color_inc = 0x11; + break; + case 8: + num_palette = 256; + color_inc = 1; + break; + default: + num_palette = 0; + color_inc = 0; + break; + } + + for (i = 0, v = 0; i < num_palette; i++, v += color_inc) + { + palette[i].red = (png_byte)v; + palette[i].green = (png_byte)v; + palette[i].blue = (png_byte)v; + } +} + +/* This function is currently unused. Do we really need it? */ +#if defined(PNG_READ_DITHER_SUPPORTED) && defined(PNG_CORRECT_PALETTE_SUPPORTED) +void /* PRIVATE */ +png_correct_palette(png_structp png_ptr, png_colorp palette, + int num_palette) +{ + png_debug(1, "in png_correct_palette\n"); +#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ + defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED) + if (png_ptr->transformations & (PNG_GAMMA | PNG_BACKGROUND)) + { + png_color back, back_1; + + if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE) + { + back.red = png_ptr->gamma_table[png_ptr->background.red]; + back.green = png_ptr->gamma_table[png_ptr->background.green]; + back.blue = png_ptr->gamma_table[png_ptr->background.blue]; + + back_1.red = png_ptr->gamma_to_1[png_ptr->background.red]; + back_1.green = png_ptr->gamma_to_1[png_ptr->background.green]; + back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue]; + } + else + { + double g; + + g = 1.0 / (png_ptr->background_gamma * png_ptr->screen_gamma); + + if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_SCREEN || + fabs(g - 1.0) < PNG_GAMMA_THRESHOLD) + { + back.red = png_ptr->background.red; + back.green = png_ptr->background.green; + back.blue = png_ptr->background.blue; + } + else + { + back.red = + (png_byte)(pow((double)png_ptr->background.red/255, g) * + 255.0 + 0.5); + back.green = + (png_byte)(pow((double)png_ptr->background.green/255, g) * + 255.0 + 0.5); + back.blue = + (png_byte)(pow((double)png_ptr->background.blue/255, g) * + 255.0 + 0.5); + } + + g = 1.0 / png_ptr->background_gamma; + + back_1.red = + (png_byte)(pow((double)png_ptr->background.red/255, g) * + 255.0 + 0.5); + back_1.green = + (png_byte)(pow((double)png_ptr->background.green/255, g) * + 255.0 + 0.5); + back_1.blue = + (png_byte)(pow((double)png_ptr->background.blue/255, g) * + 255.0 + 0.5); + } + + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + png_uint_32 i; + + for (i = 0; i < (png_uint_32)num_palette; i++) + { + if (i < png_ptr->num_trans && png_ptr->trans[i] == 0) + { + palette[i] = back; + } + else if (i < png_ptr->num_trans && png_ptr->trans[i] != 0xff) + { + png_byte v, w; + + v = png_ptr->gamma_to_1[png_ptr->palette[i].red]; + png_composite(w, v, png_ptr->trans[i], back_1.red); + palette[i].red = png_ptr->gamma_from_1[w]; + + v = png_ptr->gamma_to_1[png_ptr->palette[i].green]; + png_composite(w, v, png_ptr->trans[i], back_1.green); + palette[i].green = png_ptr->gamma_from_1[w]; + + v = png_ptr->gamma_to_1[png_ptr->palette[i].blue]; + png_composite(w, v, png_ptr->trans[i], back_1.blue); + palette[i].blue = png_ptr->gamma_from_1[w]; + } + else + { + palette[i].red = png_ptr->gamma_table[palette[i].red]; + palette[i].green = png_ptr->gamma_table[palette[i].green]; + palette[i].blue = png_ptr->gamma_table[palette[i].blue]; + } + } + } + else + { + int i; + + for (i = 0; i < num_palette; i++) + { + if (palette[i].red == (png_byte)png_ptr->trans_values.gray) + { + palette[i] = back; + } + else + { + palette[i].red = png_ptr->gamma_table[palette[i].red]; + palette[i].green = png_ptr->gamma_table[palette[i].green]; + palette[i].blue = png_ptr->gamma_table[palette[i].blue]; + } + } + } + } + else +#endif +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (png_ptr->transformations & PNG_GAMMA) + { + int i; + + for (i = 0; i < num_palette; i++) + { + palette[i].red = png_ptr->gamma_table[palette[i].red]; + palette[i].green = png_ptr->gamma_table[palette[i].green]; + palette[i].blue = png_ptr->gamma_table[palette[i].blue]; + } + } +#if defined(PNG_READ_BACKGROUND_SUPPORTED) + else +#endif +#endif +#if defined(PNG_READ_BACKGROUND_SUPPORTED) + if (png_ptr->transformations & PNG_BACKGROUND) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + png_color back; + + back.red = (png_byte)png_ptr->background.red; + back.green = (png_byte)png_ptr->background.green; + back.blue = (png_byte)png_ptr->background.blue; + + for (i = 0; i < (int)png_ptr->num_trans; i++) + { + if (png_ptr->trans[i] == 0) + { + palette[i].red = back.red; + palette[i].green = back.green; + palette[i].blue = back.blue; + } + else if (png_ptr->trans[i] != 0xff) + { + png_composite(palette[i].red, png_ptr->palette[i].red, + png_ptr->trans[i], back.red); + png_composite(palette[i].green, png_ptr->palette[i].green, + png_ptr->trans[i], back.green); + png_composite(palette[i].blue, png_ptr->palette[i].blue, + png_ptr->trans[i], back.blue); + } + } + } + else /* assume grayscale palette (what else could it be?) */ + { + int i; + + for (i = 0; i < num_palette; i++) + { + if (i == (png_byte)png_ptr->trans_values.gray) + { + palette[i].red = (png_byte)png_ptr->background.red; + palette[i].green = (png_byte)png_ptr->background.green; + palette[i].blue = (png_byte)png_ptr->background.blue; + } + } + } + } +#endif +} +#endif + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) +/* Replace any alpha or transparency with the supplied background color. + * "background" is already in the screen gamma, while "background_1" is + * at a gamma of 1.0. Paletted files have already been taken care of. + */ +void /* PRIVATE */ +png_do_background(png_row_infop row_info, png_bytep row, + png_color_16p trans_values, png_color_16p background +#if defined(PNG_READ_GAMMA_SUPPORTED) + , png_color_16p background_1, + png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1, + png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1, + png_uint_16pp gamma_16_to_1, int gamma_shift +#endif + ) +{ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width=row_info->width; + int shift; + + png_debug(1, "in png_do_background\n"); + if (background != NULL && +#if defined(PNG_USELESS_TESTS_SUPPORTED) + row != NULL && row_info != NULL && +#endif + (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) || + (row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_values))) + { + switch (row_info->color_type) + { + case PNG_COLOR_TYPE_GRAY: + { + switch (row_info->bit_depth) + { + case 1: + { + sp = row; + shift = 7; + for (i = 0; i < row_width; i++) + { + if ((png_uint_16)((*sp >> shift) & 0x01) + == trans_values->gray) + { + *sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff); + *sp |= (png_byte)(background->gray << shift); + } + if (!shift) + { + shift = 7; + sp++; + } + else + shift--; + } + break; + } + case 2: + { +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (gamma_table != NULL) + { + sp = row; + shift = 6; + for (i = 0; i < row_width; i++) + { + if ((png_uint_16)((*sp >> shift) & 0x03) + == trans_values->gray) + { + *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff); + *sp |= (png_byte)(background->gray << shift); + } + else + { + png_byte p = (png_byte)((*sp >> shift) & 0x03); + png_byte g = (png_byte)((gamma_table [p | (p << 2) | + (p << 4) | (p << 6)] >> 6) & 0x03); + *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff); + *sp |= (png_byte)(g << shift); + } + if (!shift) + { + shift = 6; + sp++; + } + else + shift -= 2; + } + } + else +#endif + { + sp = row; + shift = 6; + for (i = 0; i < row_width; i++) + { + if ((png_uint_16)((*sp >> shift) & 0x03) + == trans_values->gray) + { + *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff); + *sp |= (png_byte)(background->gray << shift); + } + if (!shift) + { + shift = 6; + sp++; + } + else + shift -= 2; + } + } + break; + } + case 4: + { +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (gamma_table != NULL) + { + sp = row; + shift = 4; + for (i = 0; i < row_width; i++) + { + if ((png_uint_16)((*sp >> shift) & 0x0f) + == trans_values->gray) + { + *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff); + *sp |= (png_byte)(background->gray << shift); + } + else + { + png_byte p = (png_byte)((*sp >> shift) & 0x0f); + png_byte g = (png_byte)((gamma_table[p | + (p << 4)] >> 4) & 0x0f); + *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff); + *sp |= (png_byte)(g << shift); + } + if (!shift) + { + shift = 4; + sp++; + } + else + shift -= 4; + } + } + else +#endif + { + sp = row; + shift = 4; + for (i = 0; i < row_width; i++) + { + if ((png_uint_16)((*sp >> shift) & 0x0f) + == trans_values->gray) + { + *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff); + *sp |= (png_byte)(background->gray << shift); + } + if (!shift) + { + shift = 4; + sp++; + } + else + shift -= 4; + } + } + break; + } + case 8: + { +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (gamma_table != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp++) + { + if (*sp == trans_values->gray) + { + *sp = (png_byte)background->gray; + } + else + { + *sp = gamma_table[*sp]; + } + } + } + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp++) + { + if (*sp == trans_values->gray) + { + *sp = (png_byte)background->gray; + } + } + } + break; + } + case 16: + { +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (gamma_16 != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp += 2) + { + png_uint_16 v; + + v = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + if (v == trans_values->gray) + { + /* background is already in screen gamma */ + *sp = (png_byte)((background->gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(background->gray & 0xff); + } + else + { + v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + } + } + } + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp += 2) + { + png_uint_16 v; + + v = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + if (v == trans_values->gray) + { + *sp = (png_byte)((background->gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(background->gray & 0xff); + } + } + } + break; + } + } + break; + } + case PNG_COLOR_TYPE_RGB: + { + if (row_info->bit_depth == 8) + { +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (gamma_table != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp += 3) + { + if (*sp == trans_values->red && + *(sp + 1) == trans_values->green && + *(sp + 2) == trans_values->blue) + { + *sp = (png_byte)background->red; + *(sp + 1) = (png_byte)background->green; + *(sp + 2) = (png_byte)background->blue; + } + else + { + *sp = gamma_table[*sp]; + *(sp + 1) = gamma_table[*(sp + 1)]; + *(sp + 2) = gamma_table[*(sp + 2)]; + } + } + } + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp += 3) + { + if (*sp == trans_values->red && + *(sp + 1) == trans_values->green && + *(sp + 2) == trans_values->blue) + { + *sp = (png_byte)background->red; + *(sp + 1) = (png_byte)background->green; + *(sp + 2) = (png_byte)background->blue; + } + } + } + } + else /* if (row_info->bit_depth == 16) */ + { +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (gamma_16 != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp += 6) + { + png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3)); + png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5)); + if (r == trans_values->red && g == trans_values->green && + b == trans_values->blue) + { + /* background is already in screen gamma */ + *sp = (png_byte)((background->red >> 8) & 0xff); + *(sp + 1) = (png_byte)(background->red & 0xff); + *(sp + 2) = (png_byte)((background->green >> 8) & 0xff); + *(sp + 3) = (png_byte)(background->green & 0xff); + *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(background->blue & 0xff); + } + else + { + png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)]; + *(sp + 2) = (png_byte)((v >> 8) & 0xff); + *(sp + 3) = (png_byte)(v & 0xff); + v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)]; + *(sp + 4) = (png_byte)((v >> 8) & 0xff); + *(sp + 5) = (png_byte)(v & 0xff); + } + } + } + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp += 6) + { + png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp+1)); + png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3)); + png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5)); + + if (r == trans_values->red && g == trans_values->green && + b == trans_values->blue) + { + *sp = (png_byte)((background->red >> 8) & 0xff); + *(sp + 1) = (png_byte)(background->red & 0xff); + *(sp + 2) = (png_byte)((background->green >> 8) & 0xff); + *(sp + 3) = (png_byte)(background->green & 0xff); + *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(background->blue & 0xff); + } + } + } + } + break; + } + case PNG_COLOR_TYPE_GRAY_ALPHA: + { + if (row_info->bit_depth == 8) + { +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (gamma_to_1 != NULL && gamma_from_1 != NULL && + gamma_table != NULL) + { + sp = row; + dp = row; + for (i = 0; i < row_width; i++, sp += 2, dp++) + { + png_uint_16 a = *(sp + 1); + + if (a == 0xff) + { + *dp = gamma_table[*sp]; + } + else if (a == 0) + { + /* background is already in screen gamma */ + *dp = (png_byte)background->gray; + } + else + { + png_byte v, w; + + v = gamma_to_1[*sp]; + png_composite(w, v, a, background_1->gray); + *dp = gamma_from_1[w]; + } + } + } + else +#endif + { + sp = row; + dp = row; + for (i = 0; i < row_width; i++, sp += 2, dp++) + { + png_byte a = *(sp + 1); + + if (a == 0xff) + { + *dp = *sp; + } +#if defined(PNG_READ_GAMMA_SUPPORTED) + else if (a == 0) + { + *dp = (png_byte)background->gray; + } + else + { + png_composite(*dp, *sp, a, background_1->gray); + } +#else + *dp = (png_byte)background->gray; +#endif + } + } + } + else /* if (png_ptr->bit_depth == 16) */ + { +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (gamma_16 != NULL && gamma_16_from_1 != NULL && + gamma_16_to_1 != NULL) + { + sp = row; + dp = row; + for (i = 0; i < row_width; i++, sp += 4, dp += 2) + { + png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3)); + + if (a == (png_uint_16)0xffff) + { + png_uint_16 v; + + v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; + *dp = (png_byte)((v >> 8) & 0xff); + *(dp + 1) = (png_byte)(v & 0xff); + } +#if defined(PNG_READ_GAMMA_SUPPORTED) + else if (a == 0) +#else + else +#endif + { + /* background is already in screen gamma */ + *dp = (png_byte)((background->gray >> 8) & 0xff); + *(dp + 1) = (png_byte)(background->gray & 0xff); + } +#if defined(PNG_READ_GAMMA_SUPPORTED) + else + { + png_uint_16 g, v, w; + + g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp]; + png_composite_16(v, g, a, background_1->gray); + w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8]; + *dp = (png_byte)((w >> 8) & 0xff); + *(dp + 1) = (png_byte)(w & 0xff); + } +#endif + } + } + else +#endif + { + sp = row; + dp = row; + for (i = 0; i < row_width; i++, sp += 4, dp += 2) + { + png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3)); + if (a == (png_uint_16)0xffff) + { + png_memcpy(dp, sp, 2); + } +#if defined(PNG_READ_GAMMA_SUPPORTED) + else if (a == 0) +#else + else +#endif + { + *dp = (png_byte)((background->gray >> 8) & 0xff); + *(dp + 1) = (png_byte)(background->gray & 0xff); + } +#if defined(PNG_READ_GAMMA_SUPPORTED) + else + { + png_uint_16 g, v; + + g = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + png_composite_16(v, g, a, background_1->gray); + *dp = (png_byte)((v >> 8) & 0xff); + *(dp + 1) = (png_byte)(v & 0xff); + } +#endif + } + } + } + break; + } + case PNG_COLOR_TYPE_RGB_ALPHA: + { + if (row_info->bit_depth == 8) + { +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (gamma_to_1 != NULL && gamma_from_1 != NULL && + gamma_table != NULL) + { + sp = row; + dp = row; + for (i = 0; i < row_width; i++, sp += 4, dp += 3) + { + png_byte a = *(sp + 3); + + if (a == 0xff) + { + *dp = gamma_table[*sp]; + *(dp + 1) = gamma_table[*(sp + 1)]; + *(dp + 2) = gamma_table[*(sp + 2)]; + } + else if (a == 0) + { + /* background is already in screen gamma */ + *dp = (png_byte)background->red; + *(dp + 1) = (png_byte)background->green; + *(dp + 2) = (png_byte)background->blue; + } + else + { + png_byte v, w; + + v = gamma_to_1[*sp]; + png_composite(w, v, a, background_1->red); + *dp = gamma_from_1[w]; + v = gamma_to_1[*(sp + 1)]; + png_composite(w, v, a, background_1->green); + *(dp + 1) = gamma_from_1[w]; + v = gamma_to_1[*(sp + 2)]; + png_composite(w, v, a, background_1->blue); + *(dp + 2) = gamma_from_1[w]; + } + } + } + else +#endif + { + sp = row; + dp = row; + for (i = 0; i < row_width; i++, sp += 4, dp += 3) + { + png_byte a = *(sp + 3); + + if (a == 0xff) + { + *dp = *sp; + *(dp + 1) = *(sp + 1); + *(dp + 2) = *(sp + 2); + } + else if (a == 0) + { + *dp = (png_byte)background->red; + *(dp + 1) = (png_byte)background->green; + *(dp + 2) = (png_byte)background->blue; + } + else + { + png_composite(*dp, *sp, a, background->red); + png_composite(*(dp + 1), *(sp + 1), a, + background->green); + png_composite(*(dp + 2), *(sp + 2), a, + background->blue); + } + } + } + } + else /* if (row_info->bit_depth == 16) */ + { +#if defined(PNG_READ_GAMMA_SUPPORTED) + if (gamma_16 != NULL && gamma_16_from_1 != NULL && + gamma_16_to_1 != NULL) + { + sp = row; + dp = row; + for (i = 0; i < row_width; i++, sp += 8, dp += 6) + { + png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6)) + << 8) + (png_uint_16)(*(sp + 7))); + if (a == (png_uint_16)0xffff) + { + png_uint_16 v; + + v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; + *dp = (png_byte)((v >> 8) & 0xff); + *(dp + 1) = (png_byte)(v & 0xff); + v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)]; + *(dp + 2) = (png_byte)((v >> 8) & 0xff); + *(dp + 3) = (png_byte)(v & 0xff); + v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)]; + *(dp + 4) = (png_byte)((v >> 8) & 0xff); + *(dp + 5) = (png_byte)(v & 0xff); + } + else if (a == 0) + { + /* background is already in screen gamma */ + *dp = (png_byte)((background->red >> 8) & 0xff); + *(dp + 1) = (png_byte)(background->red & 0xff); + *(dp + 2) = (png_byte)((background->green >> 8) & 0xff); + *(dp + 3) = (png_byte)(background->green & 0xff); + *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff); + *(dp + 5) = (png_byte)(background->blue & 0xff); + } + else + { + png_uint_16 v, w, x; + + v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp]; + png_composite_16(w, v, a, background_1->red); + x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8]; + *dp = (png_byte)((x >> 8) & 0xff); + *(dp + 1) = (png_byte)(x & 0xff); + v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)]; + png_composite_16(w, v, a, background_1->green); + x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8]; + *(dp + 2) = (png_byte)((x >> 8) & 0xff); + *(dp + 3) = (png_byte)(x & 0xff); + v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)]; + png_composite_16(w, v, a, background_1->blue); + x = gamma_16_from_1[(w & 0xff) >> gamma_shift][w >> 8]; + *(dp + 4) = (png_byte)((x >> 8) & 0xff); + *(dp + 5) = (png_byte)(x & 0xff); + } + } + } + else +#endif + { + sp = row; + dp = row; + for (i = 0; i < row_width; i++, sp += 8, dp += 6) + { + png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6)) + << 8) + (png_uint_16)(*(sp + 7))); + if (a == (png_uint_16)0xffff) + { + png_memcpy(dp, sp, 6); + } + else if (a == 0) + { + *dp = (png_byte)((background->red >> 8) & 0xff); + *(dp + 1) = (png_byte)(background->red & 0xff); + *(dp + 2) = (png_byte)((background->green >> 8) & 0xff); + *(dp + 3) = (png_byte)(background->green & 0xff); + *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff); + *(dp + 5) = (png_byte)(background->blue & 0xff); + } + else + { + png_uint_16 v; + + png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8) + + *(sp + 3)); + png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8) + + *(sp + 5)); + + png_composite_16(v, r, a, background->red); + *dp = (png_byte)((v >> 8) & 0xff); + *(dp + 1) = (png_byte)(v & 0xff); + png_composite_16(v, g, a, background->green); + *(dp + 2) = (png_byte)((v >> 8) & 0xff); + *(dp + 3) = (png_byte)(v & 0xff); + png_composite_16(v, b, a, background->blue); + *(dp + 4) = (png_byte)((v >> 8) & 0xff); + *(dp + 5) = (png_byte)(v & 0xff); + } + } + } + } + break; + } + } + + if (row_info->color_type & PNG_COLOR_MASK_ALPHA) + { + row_info->color_type &= ~PNG_COLOR_MASK_ALPHA; + row_info->channels--; + row_info->pixel_depth = (png_byte)(row_info->channels * + row_info->bit_depth); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width); + } + } +} +#endif + +#if defined(PNG_READ_GAMMA_SUPPORTED) +/* Gamma correct the image, avoiding the alpha channel. Make sure + * you do this after you deal with the transparency issue on grayscale + * or RGB images. If your bit depth is 8, use gamma_table, if it + * is 16, use gamma_16_table and gamma_shift. Build these with + * build_gamma_table(). + */ +void /* PRIVATE */ +png_do_gamma(png_row_infop row_info, png_bytep row, + png_bytep gamma_table, png_uint_16pp gamma_16_table, + int gamma_shift) +{ + png_bytep sp; + png_uint_32 i; + png_uint_32 row_width=row_info->width; + + png_debug(1, "in png_do_gamma\n"); + if ( +#if defined(PNG_USELESS_TESTS_SUPPORTED) + row != NULL && row_info != NULL && +#endif + ((row_info->bit_depth <= 8 && gamma_table != NULL) || + (row_info->bit_depth == 16 && gamma_16_table != NULL))) + { + switch (row_info->color_type) + { + case PNG_COLOR_TYPE_RGB: + { + if (row_info->bit_depth == 8) + { + sp = row; + for (i = 0; i < row_width; i++) + { + *sp = gamma_table[*sp]; + sp++; + *sp = gamma_table[*sp]; + sp++; + *sp = gamma_table[*sp]; + sp++; + } + } + else /* if (row_info->bit_depth == 16) */ + { + sp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 v; + + v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + } + } + break; + } + case PNG_COLOR_TYPE_RGB_ALPHA: + { + if (row_info->bit_depth == 8) + { + sp = row; + for (i = 0; i < row_width; i++) + { + *sp = gamma_table[*sp]; + sp++; + *sp = gamma_table[*sp]; + sp++; + *sp = gamma_table[*sp]; + sp++; + sp++; + } + } + else /* if (row_info->bit_depth == 16) */ + { + sp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 4; + } + } + break; + } + case PNG_COLOR_TYPE_GRAY_ALPHA: + { + if (row_info->bit_depth == 8) + { + sp = row; + for (i = 0; i < row_width; i++) + { + *sp = gamma_table[*sp]; + sp += 2; + } + } + else /* if (row_info->bit_depth == 16) */ + { + sp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 4; + } + } + break; + } + case PNG_COLOR_TYPE_GRAY: + { + if (row_info->bit_depth == 2) + { + sp = row; + for (i = 0; i < row_width; i += 4) + { + int a = *sp & 0xc0; + int b = *sp & 0x30; + int c = *sp & 0x0c; + int d = *sp & 0x03; + + *sp = (png_byte)( + ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)]) ) & 0xc0)| + ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)| + ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)| + ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) )); + sp++; + } + } + if (row_info->bit_depth == 4) + { + sp = row; + for (i = 0; i < row_width; i += 2) + { + int msb = *sp & 0xf0; + int lsb = *sp & 0x0f; + + *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0) + | (((int)gamma_table[(lsb << 4) | lsb]) >> 4)); + sp++; + } + } + else if (row_info->bit_depth == 8) + { + sp = row; + for (i = 0; i < row_width; i++) + { + *sp = gamma_table[*sp]; + sp++; + } + } + else if (row_info->bit_depth == 16) + { + sp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + } + } + break; + } + } + } +} +#endif + +#if defined(PNG_READ_EXPAND_SUPPORTED) +/* Expands a palette row to an RGB or RGBA row depending + * upon whether you supply trans and num_trans. + */ +void /* PRIVATE */ +png_do_expand_palette(png_row_infop row_info, png_bytep row, + png_colorp palette, png_bytep trans, int num_trans) +{ + int shift, value; + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width=row_info->width; + + png_debug(1, "in png_do_expand_palette\n"); + if ( +#if defined(PNG_USELESS_TESTS_SUPPORTED) + row != NULL && row_info != NULL && +#endif + row_info->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (row_info->bit_depth < 8) + { + switch (row_info->bit_depth) + { + case 1: + { + sp = row + (png_size_t)((row_width - 1) >> 3); + dp = row + (png_size_t)row_width - 1; + shift = 7 - (int)((row_width + 7) & 0x07); + for (i = 0; i < row_width; i++) + { + if ((*sp >> shift) & 0x01) + *dp = 1; + else + *dp = 0; + if (shift == 7) + { + shift = 0; + sp--; + } + else + shift++; + + dp--; + } + break; + } + case 2: + { + sp = row + (png_size_t)((row_width - 1) >> 2); + dp = row + (png_size_t)row_width - 1; + shift = (int)((3 - ((row_width + 3) & 0x03)) << 1); + for (i = 0; i < row_width; i++) + { + value = (*sp >> shift) & 0x03; + *dp = (png_byte)value; + if (shift == 6) + { + shift = 0; + sp--; + } + else + shift += 2; + + dp--; + } + break; + } + case 4: + { + sp = row + (png_size_t)((row_width - 1) >> 1); + dp = row + (png_size_t)row_width - 1; + shift = (int)((row_width & 0x01) << 2); + for (i = 0; i < row_width; i++) + { + value = (*sp >> shift) & 0x0f; + *dp = (png_byte)value; + if (shift == 4) + { + shift = 0; + sp--; + } + else + shift += 4; + + dp--; + } + break; + } + } + row_info->bit_depth = 8; + row_info->pixel_depth = 8; + row_info->rowbytes = row_width; + } + switch (row_info->bit_depth) + { + case 8: + { + if (trans != NULL) + { + sp = row + (png_size_t)row_width - 1; + dp = row + (png_size_t)(row_width << 2) - 1; + + for (i = 0; i < row_width; i++) + { + if ((int)(*sp) >= num_trans) + *dp-- = 0xff; + else + *dp-- = trans[*sp]; + *dp-- = palette[*sp].blue; + *dp-- = palette[*sp].green; + *dp-- = palette[*sp].red; + sp--; + } + row_info->bit_depth = 8; + row_info->pixel_depth = 32; + row_info->rowbytes = row_width * 4; + row_info->color_type = 6; + row_info->channels = 4; + } + else + { + sp = row + (png_size_t)row_width - 1; + dp = row + (png_size_t)(row_width * 3) - 1; + + for (i = 0; i < row_width; i++) + { + *dp-- = palette[*sp].blue; + *dp-- = palette[*sp].green; + *dp-- = palette[*sp].red; + sp--; + } + row_info->bit_depth = 8; + row_info->pixel_depth = 24; + row_info->rowbytes = row_width * 3; + row_info->color_type = 2; + row_info->channels = 3; + } + break; + } + } + } +} + +/* If the bit depth < 8, it is expanded to 8. Also, if the already + * expanded transparency value is supplied, an alpha channel is built. + */ +void /* PRIVATE */ +png_do_expand(png_row_infop row_info, png_bytep row, + png_color_16p trans_value) +{ + int shift, value; + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width=row_info->width; + + png_debug(1, "in png_do_expand\n"); +#if defined(PNG_USELESS_TESTS_SUPPORTED) + if (row != NULL && row_info != NULL) +#endif + { + if (row_info->color_type == PNG_COLOR_TYPE_GRAY) + { + png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0); + + if (row_info->bit_depth < 8) + { + switch (row_info->bit_depth) + { + case 1: + { + gray = (png_uint_16)((gray&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 = (png_uint_16)((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 = (png_uint_16)((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; + } + } + row_info->bit_depth = 8; + row_info->pixel_depth = 8; + row_info->rowbytes = row_width; + } + + if (trans_value != NULL) + { + if (row_info->bit_depth == 8) + { + gray = gray & 0xff; + sp = row + (png_size_t)row_width - 1; + dp = row + (png_size_t)(row_width << 1) - 1; + for (i = 0; i < row_width; i++) + { + if (*sp == gray) + *dp-- = 0; + else + *dp-- = 0xff; + *dp-- = *sp--; + } + } + else if (row_info->bit_depth == 16) + { + png_byte gray_high = (gray >> 8) & 0xff; + png_byte gray_low = gray & 0xff; + sp = row + row_info->rowbytes - 1; + dp = row + (row_info->rowbytes << 1) - 1; + for (i = 0; i < row_width; i++) + { + if (*(sp-1) == gray_high && *(sp) == gray_low) + { + *dp-- = 0; + *dp-- = 0; + } + else + { + *dp-- = 0xff; + *dp-- = 0xff; + } + *dp-- = *sp--; + *dp-- = *sp--; + } + } + row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA; + row_info->channels = 2; + row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, + row_width); + } + } + else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value) + { + if (row_info->bit_depth == 8) + { + png_byte red = trans_value->red & 0xff; + png_byte green = trans_value->green & 0xff; + png_byte blue = trans_value->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 = (trans_value->red >> 8) & 0xff; + png_byte green_high = (trans_value->green >> 8) & 0xff; + png_byte blue_high = (trans_value->blue >> 8) & 0xff; + png_byte red_low = trans_value->red & 0xff; + png_byte green_low = trans_value->green & 0xff; + png_byte blue_low = trans_value->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 + +#if defined(PNG_READ_DITHER_SUPPORTED) +void /* PRIVATE */ +png_do_dither(png_row_infop row_info, png_bytep row, + png_bytep palette_lookup, png_bytep dither_lookup) +{ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width=row_info->width; + + png_debug(1, "in png_do_dither\n"); +#if defined(PNG_USELESS_TESTS_SUPPORTED) + if (row != NULL && row_info != NULL) +#endif + { + if (row_info->color_type == PNG_COLOR_TYPE_RGB && + palette_lookup && row_info->bit_depth == 8) + { + int r, g, b, p; + sp = row; + dp = row; + for (i = 0; i < row_width; i++) + { + r = *sp++; + g = *sp++; + b = *sp++; + + /* this looks real messy, but the compiler will reduce + it down to a reasonable formula. For example, with + 5 bits per color, we get: + p = (((r >> 3) & 0x1f) << 10) | + (((g >> 3) & 0x1f) << 5) | + ((b >> 3) & 0x1f); + */ + p = (((r >> (8 - PNG_DITHER_RED_BITS)) & + ((1 << PNG_DITHER_RED_BITS) - 1)) << + (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) | + (((g >> (8 - PNG_DITHER_GREEN_BITS)) & + ((1 << PNG_DITHER_GREEN_BITS) - 1)) << + (PNG_DITHER_BLUE_BITS)) | + ((b >> (8 - PNG_DITHER_BLUE_BITS)) & + ((1 << PNG_DITHER_BLUE_BITS) - 1)); + + *dp++ = palette_lookup[p]; + } + row_info->color_type = PNG_COLOR_TYPE_PALETTE; + row_info->channels = 1; + row_info->pixel_depth = row_info->bit_depth; + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width); + } + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA && + palette_lookup != NULL && row_info->bit_depth == 8) + { + int r, g, b, p; + sp = row; + dp = row; + for (i = 0; i < row_width; i++) + { + r = *sp++; + g = *sp++; + b = *sp++; + sp++; + + p = (((r >> (8 - PNG_DITHER_RED_BITS)) & + ((1 << PNG_DITHER_RED_BITS) - 1)) << + (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) | + (((g >> (8 - PNG_DITHER_GREEN_BITS)) & + ((1 << PNG_DITHER_GREEN_BITS) - 1)) << + (PNG_DITHER_BLUE_BITS)) | + ((b >> (8 - PNG_DITHER_BLUE_BITS)) & + ((1 << PNG_DITHER_BLUE_BITS) - 1)); + + *dp++ = palette_lookup[p]; + } + row_info->color_type = PNG_COLOR_TYPE_PALETTE; + row_info->channels = 1; + row_info->pixel_depth = row_info->bit_depth; + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width); + } + else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE && + dither_lookup && row_info->bit_depth == 8) + { + sp = row; + for (i = 0; i < row_width; i++, sp++) + { + *sp = dither_lookup[*sp]; + } + } + } +} +#endif + +#ifdef PNG_FLOATING_POINT_SUPPORTED +#if defined(PNG_READ_GAMMA_SUPPORTED) +static PNG_CONST int png_gamma_shift[] = + {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0, 0x00}; + +/* We build the 8- or 16-bit gamma tables here. Note that for 16-bit + * tables, we don't make a full table if we are reducing to 8-bit in + * the future. Note also how the gamma_16 tables are segmented so that + * we don't need to allocate > 64K chunks for a full 16-bit table. + */ +void /* PRIVATE */ +png_build_gamma_table(png_structp png_ptr) +{ + png_debug(1, "in png_build_gamma_table\n"); + + if (png_ptr->bit_depth <= 8) + { + int i; + double g; + + if (png_ptr->screen_gamma > .000001) + g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); + else + g = 1.0; + + png_ptr->gamma_table = (png_bytep)png_malloc(png_ptr, + (png_uint_32)256); + + for (i = 0; i < 256; i++) + { + png_ptr->gamma_table[i] = (png_byte)(pow((double)i / 255.0, + g) * 255.0 + .5); + } + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) + if (png_ptr->transformations & ((PNG_BACKGROUND) | PNG_RGB_TO_GRAY)) + { + + g = 1.0 / (png_ptr->gamma); + + png_ptr->gamma_to_1 = (png_bytep)png_malloc(png_ptr, + (png_uint_32)256); + + for (i = 0; i < 256; i++) + { + png_ptr->gamma_to_1[i] = (png_byte)(pow((double)i / 255.0, + g) * 255.0 + .5); + } + + + png_ptr->gamma_from_1 = (png_bytep)png_malloc(png_ptr, + (png_uint_32)256); + + if(png_ptr->screen_gamma > 0.000001) + g = 1.0 / png_ptr->screen_gamma; + else + g = png_ptr->gamma; /* probably doing rgb_to_gray */ + + for (i = 0; i < 256; i++) + { + png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0, + g) * 255.0 + .5); + + } + } +#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */ + } + else + { + double g; + int i, j, shift, num; + int sig_bit; + png_uint_32 ig; + + if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) + { + sig_bit = (int)png_ptr->sig_bit.red; + if ((int)png_ptr->sig_bit.green > sig_bit) + sig_bit = png_ptr->sig_bit.green; + if ((int)png_ptr->sig_bit.blue > sig_bit) + sig_bit = png_ptr->sig_bit.blue; + } + else + { + sig_bit = (int)png_ptr->sig_bit.gray; + } + + if (sig_bit > 0) + shift = 16 - sig_bit; + else + shift = 0; + + if (png_ptr->transformations & PNG_16_TO_8) + { + if (shift < (16 - PNG_MAX_GAMMA_8)) + shift = (16 - PNG_MAX_GAMMA_8); + } + + if (shift > 8) + shift = 8; + if (shift < 0) + shift = 0; + + png_ptr->gamma_shift = (png_byte)shift; + + num = (1 << (8 - shift)); + + if (png_ptr->screen_gamma > .000001) + g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); + else + g = 1.0; + + png_ptr->gamma_16_table = (png_uint_16pp)png_malloc(png_ptr, + (png_uint_32)(num * png_sizeof (png_uint_16p))); + + if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND)) + { + double fin, fout; + png_uint_32 last, max; + + for (i = 0; i < num; i++) + { + png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr, + (png_uint_32)(256 * png_sizeof (png_uint_16))); + } + + g = 1.0 / g; + last = 0; + for (i = 0; i < 256; i++) + { + fout = ((double)i + 0.5) / 256.0; + fin = pow(fout, g); + max = (png_uint_32)(fin * (double)((png_uint_32)num << 8)); + while (last <= max) + { + png_ptr->gamma_16_table[(int)(last & (0xff >> shift))] + [(int)(last >> (8 - shift))] = (png_uint_16)( + (png_uint_16)i | ((png_uint_16)i << 8)); + last++; + } + } + while (last < ((png_uint_32)num << 8)) + { + png_ptr->gamma_16_table[(int)(last & (0xff >> shift))] + [(int)(last >> (8 - shift))] = (png_uint_16)65535L; + last++; + } + } + else + { + for (i = 0; i < num; i++) + { + png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr, + (png_uint_32)(256 * png_sizeof (png_uint_16))); + + ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4); + for (j = 0; j < 256; j++) + { + png_ptr->gamma_16_table[i][j] = + (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) / + 65535.0, g) * 65535.0 + .5); + } + } + } + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) + if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY)) + { + + g = 1.0 / (png_ptr->gamma); + + png_ptr->gamma_16_to_1 = (png_uint_16pp)png_malloc(png_ptr, + (png_uint_32)(num * png_sizeof (png_uint_16p ))); + + for (i = 0; i < num; i++) + { + png_ptr->gamma_16_to_1[i] = (png_uint_16p)png_malloc(png_ptr, + (png_uint_32)(256 * png_sizeof (png_uint_16))); + + ig = (((png_uint_32)i * + (png_uint_32)png_gamma_shift[shift]) >> 4); + for (j = 0; j < 256; j++) + { + png_ptr->gamma_16_to_1[i][j] = + (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) / + 65535.0, g) * 65535.0 + .5); + } + } + + if(png_ptr->screen_gamma > 0.000001) + g = 1.0 / png_ptr->screen_gamma; + else + g = png_ptr->gamma; /* probably doing rgb_to_gray */ + + png_ptr->gamma_16_from_1 = (png_uint_16pp)png_malloc(png_ptr, + (png_uint_32)(num * png_sizeof (png_uint_16p))); + + for (i = 0; i < num; i++) + { + png_ptr->gamma_16_from_1[i] = (png_uint_16p)png_malloc(png_ptr, + (png_uint_32)(256 * png_sizeof (png_uint_16))); + + ig = (((png_uint_32)i * + (png_uint_32)png_gamma_shift[shift]) >> 4); + for (j = 0; j < 256; j++) + { + png_ptr->gamma_16_from_1[i][j] = + (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) / + 65535.0, g) * 65535.0 + .5); + } + } + } +#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */ + } +} +#endif +/* To do: install integer version of png_build_gamma_table here */ +#endif + +#if defined(PNG_MNG_FEATURES_SUPPORTED) +/* undoes intrapixel differencing */ +void /* PRIVATE */ +png_do_read_intrapixel(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_read_intrapixel\n"); + if ( +#if defined(PNG_USELESS_TESTS_SUPPORTED) + row != NULL && row_info != NULL && +#endif + (row_info->color_type & PNG_COLOR_MASK_COLOR)) + { + int bytes_per_pixel; + png_uint_32 row_width = row_info->width; + if (row_info->bit_depth == 8) + { + png_bytep rp; + png_uint_32 i; + + if (row_info->color_type == PNG_COLOR_TYPE_RGB) + bytes_per_pixel = 3; + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + bytes_per_pixel = 4; + else + return; + + for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) + { + *(rp) = (png_byte)((256 + *rp + *(rp+1))&0xff); + *(rp+2) = (png_byte)((256 + *(rp+2) + *(rp+1))&0xff); + } + } + else if (row_info->bit_depth == 16) + { + png_bytep rp; + png_uint_32 i; + + if (row_info->color_type == PNG_COLOR_TYPE_RGB) + bytes_per_pixel = 6; + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + bytes_per_pixel = 8; + else + return; + + for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) + { + png_uint_32 s0 = (*(rp ) << 8) | *(rp+1); + png_uint_32 s1 = (*(rp+2) << 8) | *(rp+3); + png_uint_32 s2 = (*(rp+4) << 8) | *(rp+5); + png_uint_32 red = (png_uint_32)((s0+s1+65536L) & 0xffffL); + png_uint_32 blue = (png_uint_32)((s2+s1+65536L) & 0xffffL); + *(rp ) = (png_byte)((red >> 8) & 0xff); + *(rp+1) = (png_byte)(red & 0xff); + *(rp+4) = (png_byte)((blue >> 8) & 0xff); + *(rp+5) = (png_byte)(blue & 0xff); + } + } + } +} +#endif /* PNG_MNG_FEATURES_SUPPORTED */ +#endif /* PNG_READ_SUPPORTED */ |