/* pngrtran.c - transforms the data in a row for PNG readers * * Last changed in libpng 1.4.2 [May 6, 2010] * Copyright (c) 1998-2010 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * * This code is released under the libpng license. * For conditions of distribution and use, see the disclaimer * and license in png.h * * This file contains functions optionally called by an application * in order to tell libpng how to handle data when reading a PNG. * Transformations that are used in both reading and writing are * in pngtrans.c. */ #define PNG_NO_PEDANTIC_WARNINGS #include "png.h" #ifdef PNG_READ_SUPPORTED #include "pngpriv.h" /* Set the action on getting a CRC error for an ancillary or critical chunk. */ void PNGAPI png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action) { png_debug(1, "in png_set_crc_action"); if (png_ptr == NULL) return; /* Tell libpng how we react to CRC errors in critical chunks */ switch (crit_action) { case PNG_CRC_NO_CHANGE: /* Leave setting as is */ break; case PNG_CRC_WARN_USE: /* Warn/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE; break; case PNG_CRC_QUIET_USE: /* Quiet/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE | PNG_FLAG_CRC_CRITICAL_IGNORE; break; case PNG_CRC_WARN_DISCARD: /* Not a valid action for critical data */ png_warning(png_ptr, "Can't discard critical data on CRC error"); case PNG_CRC_ERROR_QUIT: /* Error/quit */ case PNG_CRC_DEFAULT: default: png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; break; } /* Tell libpng how we react to CRC errors in ancillary chunks */ switch (ancil_action) { case PNG_CRC_NO_CHANGE: /* Leave setting as is */ break; case PNG_CRC_WARN_USE: /* Warn/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE; break; case PNG_CRC_QUIET_USE: /* Quiet/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN; break; case PNG_CRC_ERROR_QUIT: /* Error/quit */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN; break; case PNG_CRC_WARN_DISCARD: /* Warn/discard data */ case PNG_CRC_DEFAULT: default: png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; break; } } #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ defined(PNG_FLOATING_POINT_SUPPORTED) /* Handle alpha and tRNS via a background color */ void PNGAPI png_set_background(png_structp png_ptr, png_color_16p background_color, int background_gamma_code, int need_expand, double background_gamma) { png_debug(1, "in png_set_background"); if (png_ptr == NULL) return; if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN) { png_warning(png_ptr, "Application must supply a known background gamma"); return; } png_ptr->transformations |= PNG_BACKGROUND; png_memcpy(&(png_ptr->background), background_color, png_sizeof(png_color_16)); png_ptr->background_gamma = (float)background_gamma; png_ptr->background_gamma_type = (png_byte)(background_gamma_code); png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0); } #endif #ifdef PNG_READ_16_TO_8_SUPPORTED /* Strip 16 bit depth files to 8 bit depth */ void PNGAPI png_set_strip_16(png_structp png_ptr) { png_debug(1, "in png_set_strip_16"); if (png_ptr == NULL) return; png_ptr->transformations |= PNG_16_TO_8; } #endif #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED void PNGAPI png_set_strip_alpha(png_structp png_ptr) { png_debug(1, "in png_set_strip_alpha"); if (png_ptr == NULL) return; png_ptr->flags |= PNG_FLAG_STRIP_ALPHA; } #endif #ifdef PNG_READ_QUANTIZE_SUPPORTED /* Quantize file to 8 bit. Supply a palette, the current number * of elements in the palette, the maximum number of elements * allowed, and a histogram if possible. If the current number * of colors is greater then the maximum number, the palette will be * modified to fit in the maximum number. "full_quantize" indicates * whether we need a quantizeing 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_quantize(png_structp png_ptr, png_colorp palette, int num_palette, int maximum_colors, png_uint_16p histogram, int full_quantize) { png_debug(1, "in png_set_quantize"); if (png_ptr == NULL) return; png_ptr->transformations |= PNG_QUANTIZE; if (!full_quantize) { int i; png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_palette * png_sizeof(png_byte))); for (i = 0; i < num_palette; i++) png_ptr->quantize_index[i] = (png_byte)i; } if (num_palette > maximum_colors) { if (histogram != NULL) { /* This is easy enough, just throw out the least used colors. * Perhaps not the best solution, but good enough. */ int i; /* Initialize an array to sort colors */ png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_palette * png_sizeof(png_byte))); /* Initialize the quantize_sort array */ for (i = 0; i < num_palette; i++) png_ptr->quantize_sort[i] = (png_byte)i; /* Find the least used palette entries by starting a * bubble sort, and running it until we have sorted * out enough colors. Note that we don't care about * sorting all the colors, just finding which are * least used. */ for (i = num_palette - 1; i >= maximum_colors; i--) { int done; /* To stop early if the list is pre-sorted */ int j; done = 1; for (j = 0; j < i; j++) { if (histogram[png_ptr->quantize_sort[j]] < histogram[png_ptr->quantize_sort[j + 1]]) { png_byte t; t = png_ptr->quantize_sort[j]; png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1]; png_ptr->quantize_sort[j + 1] = t; done = 0; } } if (done) break; } /* Swap the palette around, and set up a table, if necessary */ if (full_quantize) { int j = num_palette; /* Put all the useful colors within the max, but don't * move the others. */ for (i = 0; i < maximum_colors; i++) { if ((int)png_ptr->quantize_sort[i] >= maximum_colors) { do j--; while ((int)png_ptr->quantize_sort[j] >= maximum_colors); palette[i] = palette[j]; } } } else { int j = num_palette; /* Move all the used colors inside the max limit, and * develop a translation table. */ for (i = 0; i < maximum_colors; i++) { /* Only move the colors we need to */ if ((int)png_ptr->quantize_sort[i] >= maximum_colors) { png_color tmp_color; do j--; while ((int)png_ptr->quantize_sort[j] >= maximum_colors); tmp_color = palette[j]; palette[j] = palette[i]; palette[i] = tmp_color; /* Indicate where the color went */ png_ptr->quantize_index[j] = (png_byte)i; png_ptr->quantize_index[i] = (png_byte)j; } } /* Find closest color for those colors we are not using */ for (i = 0; i < num_palette; i++) { if ((int)png_ptr->quantize_index[i] >= maximum_colors) { int min_d, k, min_k, d_index; /* Find the closest color to one we threw out */ d_index = png_ptr->quantize_index[i]; min_d = PNG_COLOR_DIST(palette[d_index], palette[0]); for (k = 1, min_k = 0; k < maximum_colors; k++) { int d; d = PNG_COLOR_DIST(palette[d_index], palette[k]); if (d < min_d) { min_d = d; min_k = k; } } /* Point to closest color */ png_ptr->quantize_index[i] = (png_byte)min_k; } } } png_free(png_ptr, png_ptr->quantize_sort); png_ptr->quantize_sort = NULL; } else { /* This is much harder to do simply (and quickly). Perhaps * we need to go through a median cut routine, but those * don't always behave themselves with only a few colors * as input. So we will just find the closest two colors, * and throw out one of them (chosen somewhat randomly). * [We don't understand this at all, so if someone wants to * work on improving it, be our guest - AED, GRP] */ int i; int max_d; int num_new_palette; png_dsortp t; png_dsortpp hash; t = NULL; /* Initialize palette index arrays */ png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_palette * png_sizeof(png_byte))); png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_palette * png_sizeof(png_byte))); /* Initialize the sort array */ for (i = 0; i < num_palette; i++) { png_ptr->index_to_palette[i] = (png_byte)i; png_ptr->palette_to_index[i] = (png_byte)i; } hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 * png_sizeof(png_dsortp))); num_new_palette = num_palette; /* Initial wild guess at how far apart the farthest pixel * pair we will be eliminating will be. Larger * numbers mean more areas will be allocated, Smaller * numbers run the risk of not saving enough data, and * having to do this all over again. * * I have not done extensive checking on this number. */ max_d = 96; while (num_new_palette > maximum_colors) { for (i = 0; i < num_new_palette - 1; i++) { int j; for (j = i + 1; j < num_new_palette; j++) { int d; d = PNG_COLOR_DIST(palette[i], palette[j]); if (d <= max_d) { t = (png_dsortp)png_malloc_warn(png_ptr, (png_uint_32)(png_sizeof(png_dsort))); if (t == NULL) break; t->next = hash[d]; t->left = (png_byte)i; t->right = (png_byte)j; hash[d] = t; } } if (t == NULL) break; } if (t != NULL) for (i = 0; i <= max_d; i++) { if (hash[i] != NULL) { png_dsortp p; for (p = hash[i]; p; p = p->next) { if ((int)png_ptr->index_to_palette[p->left] < num_new_palette && (int)png_ptr->index_to_palette[p->right] < num_new_palette) { int j, next_j; if (num_new_palette & 0x01) { j = p->left; next_j = p->right; } else { j = p->right; next_j = p->left; } num_new_palette--; palette[png_ptr->index_to_palette[j]] = palette[num_new_palette]; if (!full_quantize) { int k; for (k = 0; k < num_palette; k++) { if (png_ptr->quantize_index[k] == png_ptr->index_to_palette[j]) png_ptr->quantize_index[k] = png_ptr->index_to_palette[next_j]; if ((int)png_ptr->quantize_index[k] == num_new_palette) png_ptr->quantize_index[k] = png_ptr->index_to_palette[j]; } } png_ptr->index_to_palette[png_ptr->palette_to_index [num_new_palette]] = png_ptr->index_to_palette[j]; png_ptr->palette_to_index[png_ptr->index_to_palette[j]] = png_ptr->palette_to_index[num_new_palette]; png_ptr->index_to_palette[j] = (png_byte)num_new_palette; png_ptr->palette_to_index[num_new_palette] = (png_byte)j; } if (num_new_palette <= maximum_colors) break; } if (num_new_palette <= maximum_colors) break; } } for (i = 0; i < 769; i++) { if (hash[i] != NULL) { png_dsortp p = hash[i]; while (p) { t = p->next; png_free(png_ptr, p); p = t; } } hash[i] = 0; } max_d += 96; } png_free(png_ptr, hash); png_free(png_ptr, png_ptr->palette_to_index); png_free(png_ptr, png_ptr->index_to_palette); png_ptr->palette_to_index = NULL; png_ptr->index_to_palette = NULL; } num_palette = maximum_colors; } if (png_ptr->palette == NULL) { png_ptr->palette = palette; } png_ptr->num_palette = (png_uint_16)num_palette; if (full_quantize) { int i; png_bytep distance; int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS; int num_red = (1 << PNG_QUANTIZE_RED_BITS); int num_green = (1 << PNG_QUANTIZE_GREEN_BITS); int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS); png_size_t num_entries = ((png_size_t)1 << total_bits); png_ptr->palette_lookup = (png_bytep )png_calloc(png_ptr, (png_uint_32)(num_entries * 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_QUANTIZE_RED_BITS)); int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS)); int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS)); for (ir = 0; ir < num_red; ir++) { /* int dr = abs(ir - r); */ int dr = ((ir > r) ? ir - r : r - ir); int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS + PNG_QUANTIZE_GREEN_BITS)); for (ig = 0; ig < num_green; ig++) { /* int dg = abs(ig - g); */ int dg = ((ig > g) ? ig - g : g - ig); int dt = dr + dg; int dm = ((dr > dg) ? dr : dg); int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS); for (ib = 0; ib < num_blue; ib++) { int d_index = index_g | ib; /* int db = abs(ib - b); */ int db = ((ib > b) ? ib - b : b - ib); int dmax = ((dm > db) ? dm : db); int d = dmax + dt + db; if (d < (int)distance[d_index]) { distance[d_index] = (png_byte)d; png_ptr->palette_lookup[d_index] = (png_byte)i; } } } } } png_free(png_ptr, distance); } } #endif /* PNG_READ_QUANTIZE_SUPPORTED */ #if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED) /* Transform the image from the file_gamma to the screen_gamma. We * only do transformations on images where the file_gamma and screen_gamma * are not close reciprocals, otherwise it slows things down slightly, and * also needlessly introduces small errors. * * We will turn off gamma transformation later if no semitransparent entries * are present in the tRNS array for palette images. We can't do it here * because we don't necessarily have the tRNS chunk yet. */ void PNGAPI png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma) { png_debug(1, "in png_set_gamma"); if (png_ptr == NULL) return; if ((fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD) || (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) || (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)) png_ptr->transformations |= PNG_GAMMA; png_ptr->gamma = (float)file_gamma; png_ptr->screen_gamma = (float)scrn_gamma; } #endif #ifdef PNG_READ_EXPAND_SUPPORTED /* Expand paletted images to RGB, expand grayscale images of * less than 8-bit depth to 8-bit depth, and expand tRNS chunks * to alpha channels. */ void PNGAPI png_set_expand(png_structp png_ptr) { png_debug(1, "in png_set_expand"); if (png_ptr == NULL) return; png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } /* GRR 19990627: the following three functions currently are identical * to png_set_expand(). However, it is entirely reasonable that someone * might wish to expand an indexed image to RGB but *not* expand a single, * fully transparent palette entry to a full alpha channel--perhaps instead * convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace * the transparent color with a particular RGB value, or drop tRNS entirely. * IOW, a future version of the library may make the transformations flag * a bit more fine-grained, with separate bits for each of these three * functions. * * More to the point, these functions make it obvious what libpng will be * doing, whereas "expand" can (and does) mean any number of things. * * GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified * to expand only the sample depth but not to expand the tRNS to alpha * and its name was changed to png_set_expand_gray_1_2_4_to_8(). */ /* Expand paletted images to RGB. */ void PNGAPI png_set_palette_to_rgb(png_structp png_ptr) { png_debug(1, "in png_set_palette_to_rgb"); if (png_ptr == NULL) return; png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } /* Expand grayscale images of less than 8-bit depth to 8 bits. */ void PNGAPI png_set_expand_gray_1_2_4_to_8(png_structp png_ptr) { png_debug(1, "in png_set_expand_gray_1_2_4_to_8"); if (png_ptr == NULL) return; png_ptr->transformations |= PNG_EXPAND; png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } /* Expand tRNS chunks to alpha channels. */ void PNGAPI png_set_tRNS_to_alpha(png_structp png_ptr) { png_debug(1, "in png_set_tRNS_to_alpha"); png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } #endif /* defined(PNG_READ_EXPAND_SUPPORTED) */ #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED void PNGAPI png_set_gray_to_rgb(png_structp png_ptr) { png_debug(1, "in png_set_gray_to_rgb"); png_ptr->transformations |= PNG_GRAY_TO_RGB; png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } #endif #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED #ifdef PNG_FLOATING_POINT_SUPPORTED /* Convert a RGB image to a grayscale of the same width. This allows us, * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image. */ void PNGAPI png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red, double green) { int red_fixed = (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"); if (png_ptr == NULL) return; switch(error_action) { case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY; break; case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN; break; case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR; } if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) #ifdef PNG_READ_EXPAND_SUPPORTED png_ptr->transformations |= PNG_EXPAND; #else { png_warning(png_ptr, "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED"); png_ptr->transformations &= ~PNG_RGB_TO_GRAY; } #endif { png_uint_16 red_int, green_int; if (red < 0 || green < 0) { red_int = 6968; /* .212671 * 32768 + .5 */ green_int = 23434; /* .715160 * 32768 + .5 */ } else if (red + green < 100000L) { red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L); green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L); } else { png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients"); red_int = 6968; green_int = 23434; } png_ptr->rgb_to_gray_red_coeff = red_int; png_ptr->rgb_to_gray_green_coeff = green_int; png_ptr->rgb_to_gray_blue_coeff = (png_uint_16)(32768 - red_int - green_int); } } #endif #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) void PNGAPI png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr read_user_transform_fn) { png_debug(1, "in png_set_read_user_transform_fn"); if (png_ptr == NULL) return; #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED png_ptr->transformations |= PNG_USER_TRANSFORM; png_ptr->read_user_transform_fn = read_user_transform_fn; #endif } #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"); { #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ defined(PNG_READ_SHIFT_SUPPORTED) || \ defined(PNG_READ_GAMMA_SUPPORTED) int color_type = png_ptr->color_type; #endif #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED) #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED /* Detect gray background and attempt to enable optimization * for gray --> RGB case * * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or * RGB_ALPHA (in which case need_expand is superfluous anyway), the * background color might actually be gray yet not be flagged as such. * This is not a problem for the current code, which uses * PNG_BACKGROUND_IS_GRAY only to decide when to do the * png_do_gray_to_rgb() transformation. */ if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) && !(color_type & PNG_COLOR_MASK_COLOR)) { png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; } else if ((png_ptr->transformations & PNG_BACKGROUND) && !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) && (png_ptr->transformations & PNG_GRAY_TO_RGB) && png_ptr->background.red == png_ptr->background.green && png_ptr->background.red == png_ptr->background.blue) { png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; png_ptr->background.gray = png_ptr->background.red; } #endif if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) && (png_ptr->transformations & PNG_EXPAND)) { if (!(color_type & PNG_COLOR_MASK_COLOR)) /* i.e., GRAY or GRAY_ALPHA */ { /* Expand background and tRNS chunks */ switch (png_ptr->bit_depth) { case 1: png_ptr->background.gray *= (png_uint_16)0xff; png_ptr->background.red = png_ptr->background.green = png_ptr->background.blue = png_ptr->background.gray; if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) { png_ptr->trans_color.gray *= (png_uint_16)0xff; png_ptr->trans_color.red = png_ptr->trans_color.green = png_ptr->trans_color.blue = png_ptr->trans_color.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_color.gray *= (png_uint_16)0x55; png_ptr->trans_color.red = png_ptr->trans_color.green = png_ptr->trans_color.blue = png_ptr->trans_color.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_color.gray *= (png_uint_16)0x11; png_ptr->trans_color.red = png_ptr->trans_color.green = png_ptr->trans_color.blue = png_ptr->trans_color.gray; } break; case 8: case 16: png_ptr->background.red = png_ptr->background.green = png_ptr->background.blue = png_ptr->background.gray; break; } } else if (color_type == PNG_COLOR_TYPE_PALETTE) { png_ptr->background.red = png_ptr->palette[png_ptr->background.index].red; png_ptr->background.green = png_ptr->palette[png_ptr->background.index].green; png_ptr->background.blue = png_ptr->palette[png_ptr->background.index].blue; #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED if (png_ptr->transformations & PNG_INVERT_ALPHA) { #ifdef PNG_READ_EXPAND_SUPPORTED if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) #endif { /* Invert the alpha channel (in tRNS) unless the pixels are * going to be expanded, in which case leave it for later */ int i, istop; istop=(int)png_ptr->num_trans; for (i=0; i<istop; i++) png_ptr->trans_alpha[i] = (png_byte)(255 - png_ptr->trans_alpha[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_alpha[i] != 0 && png_ptr->trans_alpha[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, png_ptr->bit_depth); #ifdef PNG_READ_BACKGROUND_SUPPORTED if (png_ptr->transformations & PNG_BACKGROUND) { if (color_type == PNG_COLOR_TYPE_PALETTE) { /* Could skip if no transparency */ png_color back, back_1; png_colorp palette = png_ptr->palette; int num_palette = png_ptr->num_palette; int i; if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE) { back.red = png_ptr->gamma_table[png_ptr->background.red]; back.green = png_ptr->gamma_table[png_ptr->background.green]; back.blue = png_ptr->gamma_table[png_ptr->background.blue]; back_1.red = png_ptr->gamma_to_1[png_ptr->background.red]; back_1.green = png_ptr->gamma_to_1[png_ptr->background.green]; back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue]; } else { double g, gs; switch (png_ptr->background_gamma_type) { case PNG_BACKGROUND_GAMMA_SCREEN: g = (png_ptr->screen_gamma); gs = 1.0; break; case PNG_BACKGROUND_GAMMA_FILE: g = 1.0 / (png_ptr->gamma); gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); break; case PNG_BACKGROUND_GAMMA_UNIQUE: g = 1.0 / (png_ptr->background_gamma); gs = 1.0 / (png_ptr->background_gamma * png_ptr->screen_gamma); break; default: g = 1.0; /* back_1 */ gs = 1.0; /* back */ } if ( fabs(gs - 1.0) < PNG_GAMMA_THRESHOLD) { back.red = (png_byte)png_ptr->background.red; back.green = (png_byte)png_ptr->background.green; back.blue = (png_byte)png_ptr->background.blue; } else { back.red = (png_byte)(pow( (double)png_ptr->background.red/255.0, gs) * 255.0 + .5); back.green = (png_byte)(pow( (double)png_ptr->background.green/255.0, gs) * 255.0 + .5); back.blue = (png_byte)(pow( (double)png_ptr->background.blue/255.0, gs) * 255.0 + .5); } back_1.red = (png_byte)(pow( (double)png_ptr->background.red/255.0, g) * 255.0 + .5); back_1.green = (png_byte)(pow( (double)png_ptr->background.green/255.0, g) * 255.0 + .5); back_1.blue = (png_byte)(pow( (double)png_ptr->background.blue/255.0, g) * 255.0 + .5); } for (i = 0; i < num_palette; i++) { if (i < (int)png_ptr->num_trans && png_ptr->trans_alpha[i] != 0xff) { if (png_ptr->trans_alpha[i] == 0) { palette[i] = back; } else /* if (png_ptr->trans_alpha[i] != 0xff) */ { png_byte v, w; v = png_ptr->gamma_to_1[palette[i].red]; png_composite(w, v, png_ptr->trans_alpha[i], back_1.red); palette[i].red = png_ptr->gamma_from_1[w]; v = png_ptr->gamma_to_1[palette[i].green]; png_composite(w, v, png_ptr->trans_alpha[i], back_1.green); palette[i].green = png_ptr->gamma_from_1[w]; v = png_ptr->gamma_to_1[palette[i].blue]; png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue); palette[i].blue = png_ptr->gamma_from_1[w]; } } else { palette[i].red = png_ptr->gamma_table[palette[i].red]; palette[i].green = png_ptr->gamma_table[palette[i].green]; palette[i].blue = png_ptr->gamma_table[palette[i].blue]; } } /* Prevent the transformations being done again, and make sure * that the now spurious alpha channel is stripped - the code * has just reduced background composition and gamma correction * to a simple alpha channel strip. */ png_ptr->transformations &= ~PNG_BACKGROUND; png_ptr->transformations &= ~PNG_GAMMA; png_ptr->transformations |= PNG_STRIP_ALPHA; } /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */ else /* color_type != PNG_COLOR_TYPE_PALETTE */ { double m = (double)(((png_uint_32)1 << png_ptr->bit_depth) - 1); double g = 1.0; double gs = 1.0; switch (png_ptr->background_gamma_type) { case PNG_BACKGROUND_GAMMA_SCREEN: g = (png_ptr->screen_gamma); gs = 1.0; break; case PNG_BACKGROUND_GAMMA_FILE: g = 1.0 / (png_ptr->gamma); gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); break; case PNG_BACKGROUND_GAMMA_UNIQUE: g = 1.0 / (png_ptr->background_gamma); gs = 1.0 / (png_ptr->background_gamma * png_ptr->screen_gamma); break; } png_ptr->background_1.gray = (png_uint_16)(pow( (double)png_ptr->background.gray / m, g) * m + .5); png_ptr->background.gray = (png_uint_16)(pow( (double)png_ptr->background.gray / m, gs) * m + .5); if ((png_ptr->background.red != png_ptr->background.green) || (png_ptr->background.red != png_ptr->background.blue) || (png_ptr->background.red != png_ptr->background.gray)) { /* RGB or RGBA with color background */ png_ptr->background_1.red = (png_uint_16)(pow( (double)png_ptr->background.red / m, g) * m + .5); png_ptr->background_1.green = (png_uint_16)(pow( (double)png_ptr->background.green / m, g) * m + .5); png_ptr->background_1.blue = (png_uint_16)(pow( (double)png_ptr->background.blue / m, g) * m + .5); png_ptr->background.red = (png_uint_16)(pow( (double)png_ptr->background.red / m, gs) * m + .5); png_ptr->background.green = (png_uint_16)(pow( (double)png_ptr->background.green / m, gs) * m + .5); png_ptr->background.blue = (png_uint_16)(pow( (double)png_ptr->background.blue / m, gs) * m + .5); } else { /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */ png_ptr->background_1.red = png_ptr->background_1.green = png_ptr->background_1.blue = png_ptr->background_1.gray; png_ptr->background.red = png_ptr->background.green = png_ptr->background.blue = png_ptr->background.gray; } } } else /* Transformation does not include PNG_BACKGROUND */ #endif /* PNG_READ_BACKGROUND_SUPPORTED */ if (color_type == PNG_COLOR_TYPE_PALETTE) { png_colorp palette = png_ptr->palette; int num_palette = png_ptr->num_palette; int i; for (i = 0; i < num_palette; i++) { palette[i].red = png_ptr->gamma_table[palette[i].red]; palette[i].green = png_ptr->gamma_table[palette[i].green]; palette[i].blue = png_ptr->gamma_table[palette[i].blue]; } /* Done the gamma correction. */ png_ptr->transformations &= ~PNG_GAMMA; } } #ifdef PNG_READ_BACKGROUND_SUPPORTED else #endif #endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */ #ifdef PNG_READ_BACKGROUND_SUPPORTED /* No GAMMA transformation */ if ((png_ptr->transformations & PNG_BACKGROUND) && (color_type == PNG_COLOR_TYPE_PALETTE)) { int i; int istop = (int)png_ptr->num_trans; png_color back; png_colorp palette = png_ptr->palette; back.red = (png_byte)png_ptr->background.red; back.green = (png_byte)png_ptr->background.green; back.blue = (png_byte)png_ptr->background.blue; for (i = 0; i < istop; i++) { if (png_ptr->trans_alpha[i] == 0) { palette[i] = back; } else if (png_ptr->trans_alpha[i] != 0xff) { /* The png_composite() macro is defined in png.h */ png_composite(palette[i].red, palette[i].red, png_ptr->trans_alpha[i], back.red); png_composite(palette[i].green, palette[i].green, png_ptr->trans_alpha[i], back.green); png_composite(palette[i].blue, palette[i].blue, png_ptr->trans_alpha[i], back.blue); } } /* Handled alpha, still need to strip the channel. */ png_ptr->transformations &= ~PNG_BACKGROUND; png_ptr->transformations |= PNG_STRIP_ALPHA; } #endif /* PNG_READ_BACKGROUND_SUPPORTED */ #ifdef PNG_READ_SHIFT_SUPPORTED if ((png_ptr->transformations & PNG_SHIFT) && (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"); #ifdef PNG_READ_EXPAND_SUPPORTED if (png_ptr->transformations & PNG_EXPAND) { if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { if (png_ptr->num_trans && (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 (info_ptr->bit_depth < 8) info_ptr->bit_depth = 8; info_ptr->num_trans = 0; } } #endif #ifdef PNG_READ_BACKGROUND_SUPPORTED if (png_ptr->transformations & PNG_BACKGROUND) { info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA; info_ptr->num_trans = 0; info_ptr->background = png_ptr->background; } #endif #ifdef PNG_READ_GAMMA_SUPPORTED if (png_ptr->transformations & PNG_GAMMA) { #ifdef PNG_FLOATING_POINT_SUPPORTED info_ptr->gamma = png_ptr->gamma; #endif #ifdef PNG_FIXED_POINT_SUPPORTED info_ptr->int_gamma = png_ptr->int_gamma; #endif } #endif #ifdef PNG_READ_16_TO_8_SUPPORTED if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16)) info_ptr->bit_depth = 8; #endif #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED if (png_ptr->transformations & PNG_GRAY_TO_RGB) info_ptr->color_type |= PNG_COLOR_MASK_COLOR; #endif #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED if (png_ptr->transformations & PNG_RGB_TO_GRAY) info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR; #endif #ifdef PNG_READ_QUANTIZE_SUPPORTED if (png_ptr->transformations & PNG_QUANTIZE) { if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) || (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) && png_ptr->palette_lookup && info_ptr->bit_depth == 8) { info_ptr->color_type = PNG_COLOR_TYPE_PALETTE; } } #endif #ifdef PNG_READ_PACK_SUPPORTED if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8)) info_ptr->bit_depth = 8; #endif if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) info_ptr->channels = 1; else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR) info_ptr->channels = 3; else info_ptr->channels = 1; #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA) info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA; #endif if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA) info_ptr->channels++; #ifdef PNG_READ_FILLER_SUPPORTED /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */ if ((png_ptr->transformations & PNG_FILLER) && ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) || (info_ptr->color_type == PNG_COLOR_TYPE_GRAY))) { info_ptr->channels++; /* If adding a true alpha channel not just filler */ if (png_ptr->transformations & PNG_ADD_ALPHA) info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; } #endif #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \ defined(PNG_READ_USER_TRANSFORM_SUPPORTED) if (png_ptr->transformations & PNG_USER_TRANSFORM) { if (info_ptr->bit_depth < png_ptr->user_transform_depth) info_ptr->bit_depth = png_ptr->user_transform_depth; if (info_ptr->channels < png_ptr->user_transform_channels) info_ptr->channels = png_ptr->user_transform_channels; } #endif info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth); info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width); #ifndef PNG_READ_EXPAND_SUPPORTED if (png_ptr) return; #endif } /* Transform the row. The order of transformations is significant, * and is very touchy. If you add a transformation, take care to * decide how it fits in with the other transformations here. */ void /* PRIVATE */ png_do_read_transformations(png_structp png_ptr) { png_debug(1, "in png_do_read_transformations"); if (png_ptr->row_buf == NULL) { #ifdef PNG_STDIO_SUPPORTED char msg[50]; png_snprintf2(msg, 50, "NULL row buffer for row %ld, pass %d", (long)png_ptr->row_number, png_ptr->pass); png_error(png_ptr, msg); #else png_error(png_ptr, "NULL row buffer"); #endif } #ifdef PNG_WARN_UNINITIALIZED_ROW if (!(png_ptr->flags & PNG_FLAG_ROW_INIT)) /* Application has failed to call either png_read_start_image() * or png_read_update_info() after setting transforms that expand * pixels. This check added to libpng-1.2.19 */ #if (PNG_WARN_UNINITIALIZED_ROW==1) png_error(png_ptr, "Uninitialized row"); #else png_warning(png_ptr, "Uninitialized row"); #endif #endif #ifdef PNG_READ_EXPAND_SUPPORTED if (png_ptr->transformations & PNG_EXPAND) { if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE) { png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1, png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans); } else { if (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND_tRNS)) png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, &(png_ptr->trans_color)); else png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, NULL); } } #endif #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA) png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, PNG_FLAG_FILLER_AFTER | (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)); #endif #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED if (png_ptr->transformations & PNG_RGB_TO_GRAY) { int rgb_error = png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info), png_ptr->row_buf + 1); if (rgb_error) { png_ptr->rgb_to_gray_status=1; if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == PNG_RGB_TO_GRAY_WARN) png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel"); if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == PNG_RGB_TO_GRAY_ERR) png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel"); } } #endif /* From Andreas Dilger e-mail to png-implement, 26 March 1998: * * In most cases, the "simple transparency" should be done prior to doing * gray-to-RGB, or you will have to test 3x as many bytes to check if a * pixel is transparent. You would also need to make sure that the * transparency information is upgraded to RGB. * * To summarize, the current flow is: * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite * with background "in place" if transparent, * convert to RGB if necessary * - Gray + alpha -> composite with gray background and remove alpha bytes, * convert to RGB if necessary * * To support RGB backgrounds for gray images we need: * - Gray + simple transparency -> convert to RGB + simple transparency, * compare 3 or 6 bytes and composite with * background "in place" if transparent * (3x compare/pixel compared to doing * composite with gray bkgrnd) * - Gray + alpha -> convert to RGB + alpha, composite with background and * remove alpha bytes (3x float * operations/pixel compared with composite * on gray background) * * Greg's change will do this. The reason it wasn't done before is for * performance, as this increases the per-pixel operations. If we would check * in advance if the background was gray or RGB, and position the gray-to-RGB * transform appropriately, then it would save a lot of work/time. */ #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED /* If gray -> RGB, do so now only if background is non-gray; else do later * for performance reasons */ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_BACKGROUND_SUPPORTED if ((png_ptr->transformations & PNG_BACKGROUND) && ((png_ptr->num_trans != 0 ) || (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1, &(png_ptr->trans_color), &(png_ptr->background) #ifdef PNG_READ_GAMMA_SUPPORTED , &(png_ptr->background_1), png_ptr->gamma_table, png_ptr->gamma_from_1, png_ptr->gamma_to_1, png_ptr->gamma_16_table, png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1, png_ptr->gamma_shift #endif ); #endif #ifdef PNG_READ_GAMMA_SUPPORTED if ((png_ptr->transformations & PNG_GAMMA) && #ifdef PNG_READ_BACKGROUND_SUPPORTED !((png_ptr->transformations & PNG_BACKGROUND) && ((png_ptr->num_trans != 0) || (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) && #endif (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)) png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1, png_ptr->gamma_table, png_ptr->gamma_16_table, png_ptr->gamma_shift); #endif #ifdef PNG_READ_16_TO_8_SUPPORTED if (png_ptr->transformations & PNG_16_TO_8) png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_QUANTIZE_SUPPORTED if (png_ptr->transformations & PNG_QUANTIZE) { png_do_quantize((png_row_infop)&(png_ptr->row_info), png_ptr->row_buf + 1, png_ptr->palette_lookup, png_ptr->quantize_index); if (png_ptr->row_info.rowbytes == (png_uint_32)0) png_error(png_ptr, "png_do_quantize returned rowbytes=0"); } #endif #ifdef PNG_READ_INVERT_SUPPORTED if (png_ptr->transformations & PNG_INVERT_MONO) png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_SHIFT_SUPPORTED if (png_ptr->transformations & PNG_SHIFT) png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1, &(png_ptr->shift)); #endif #ifdef PNG_READ_PACK_SUPPORTED if (png_ptr->transformations & PNG_PACK) png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_BGR_SUPPORTED if (png_ptr->transformations & PNG_BGR) png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_PACKSWAP_SUPPORTED if (png_ptr->transformations & PNG_PACKSWAP) png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED /* If gray -> RGB, do so now only if we did not do so above */ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && (png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_FILLER_SUPPORTED if (png_ptr->transformations & PNG_FILLER) png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, (png_uint_32)png_ptr->filler, png_ptr->flags); #endif #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED if (png_ptr->transformations & PNG_INVERT_ALPHA) png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED if (png_ptr->transformations & PNG_SWAP_ALPHA) png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_SWAP_SUPPORTED if (png_ptr->transformations & PNG_SWAP_BYTES) png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED if (png_ptr->transformations & PNG_USER_TRANSFORM) { if (png_ptr->read_user_transform_fn != NULL) (*(png_ptr->read_user_transform_fn)) /* User read transform function */ (png_ptr, /* png_ptr */ &(png_ptr->row_info), /* row_info: */ /* png_uint_32 width; width of row */ /* png_uint_32 rowbytes; number of bytes in row */ /* png_byte color_type; color type of pixels */ /* png_byte bit_depth; bit depth of samples */ /* png_byte channels; number of channels (1-4) */ /* png_byte pixel_depth; bits per pixel (depth*channels) */ png_ptr->row_buf + 1); /* start of pixel data for row */ #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED if (png_ptr->user_transform_depth) png_ptr->row_info.bit_depth = png_ptr->user_transform_depth; if (png_ptr->user_transform_channels) png_ptr->row_info.channels = png_ptr->user_transform_channels; #endif png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth * png_ptr->row_info.channels); png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth, png_ptr->row_info.width); } #endif } #ifdef PNG_READ_PACK_SUPPORTED /* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel, * without changing the actual values. Thus, if you had a row with * a bit depth of 1, you would end up with bytes that only contained * the numbers 0 or 1. If you would rather they contain 0 and 255, use * png_do_shift() after this. */ void /* PRIVATE */ png_do_unpack(png_row_infop row_info, png_bytep row) { png_debug(1, "in png_do_unpack"); if (row_info->bit_depth < 8) { png_uint_32 i; png_uint_32 row_width=row_info->width; switch (row_info->bit_depth) { case 1: { png_bytep sp = row + (png_size_t)((row_width - 1) >> 3); png_bytep dp = row + (png_size_t)row_width - 1; png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07); for (i = 0; i < row_width; i++) { *dp = (png_byte)((*sp >> shift) & 0x01); if (shift == 7) { shift = 0; sp--; } else shift++; dp--; } break; } case 2: { png_bytep sp = row + (png_size_t)((row_width - 1) >> 2); png_bytep dp = row + (png_size_t)row_width - 1; png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1); for (i = 0; i < row_width; i++) { *dp = (png_byte)((*sp >> shift) & 0x03); if (shift == 6) { shift = 0; sp--; } else shift += 2; dp--; } break; } case 4: { png_bytep sp = row + (png_size_t)((row_width - 1) >> 1); png_bytep dp = row + (png_size_t)row_width - 1; png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2); for (i = 0; i < row_width; i++) { *dp = (png_byte)((*sp >> shift) & 0x0f); if (shift == 4) { shift = 0; sp--; } else shift = 4; dp--; } break; } } row_info->bit_depth = 8; row_info->pixel_depth = (png_byte)(8 * row_info->channels); row_info->rowbytes = row_width * row_info->channels; } } #endif #ifdef PNG_READ_SHIFT_SUPPORTED /* Reverse the effects of png_do_shift. This routine merely shifts the * pixels back to their significant bits values. Thus, if you have * a row of bit depth 8, but only 5 are significant, this will shift * the values back to 0 through 31. */ void /* PRIVATE */ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) { png_debug(1, "in png_do_unshift"); if ( row_info->color_type != PNG_COLOR_TYPE_PALETTE) { int shift[4]; int channels = 0; int c; png_uint_16 value = 0; png_uint_32 row_width = row_info->width; if (row_info->color_type & PNG_COLOR_MASK_COLOR) { shift[channels++] = row_info->bit_depth - sig_bits->red; shift[channels++] = row_info->bit_depth - sig_bits->green; shift[channels++] = row_info->bit_depth - sig_bits->blue; } else { shift[channels++] = row_info->bit_depth - sig_bits->gray; } if (row_info->color_type & PNG_COLOR_MASK_ALPHA) { shift[channels++] = row_info->bit_depth - sig_bits->alpha; } for (c = 0; c < channels; c++) { if (shift[c] <= 0) shift[c] = 0; else value = 1; } if (!value) return; switch (row_info->bit_depth) { case 2: { png_bytep bp; png_uint_32 i; png_uint_32 istop = row_info->rowbytes; for (bp = row, i = 0; i < istop; i++) { *bp >>= 1; *bp++ &= 0x55; } break; } case 4: { png_bytep bp = row; png_uint_32 i; png_uint_32 istop = row_info->rowbytes; png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) | (png_byte)((int)0xf >> shift[0])); for (i = 0; i < istop; i++) { *bp >>= shift[0]; *bp++ &= mask; } break; } case 8: { png_bytep bp = row; png_uint_32 i; png_uint_32 istop = row_width * channels; for (i = 0; i < istop; i++) { *bp++ >>= shift[i%channels]; } break; } case 16: { png_bytep bp = row; png_uint_32 i; png_uint_32 istop = channels * row_width; for (i = 0; i < istop; i++) { value = (png_uint_16)((*bp << 8) + *(bp + 1)); value >>= shift[i%channels]; *bp++ = (png_byte)(value >> 8); *bp++ = (png_byte)(value & 0xff); } break; } } } } #endif #ifdef PNG_READ_16_TO_8_SUPPORTED /* Chop rows of bit depth 16 down to 8 */ void /* PRIVATE */ png_do_chop(png_row_infop row_info, png_bytep row) { png_debug(1, "in png_do_chop"); if (row_info->bit_depth == 16) { png_bytep sp = row; png_bytep dp = row; png_uint_32 i; png_uint_32 istop = row_info->width * row_info->channels; for (i = 0; i<istop; i++, sp += 2, dp++) { #ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED /* This does a more accurate scaling of the 16-bit color * value, rather than a simple low-byte truncation. * * What the ideal calculation should be: * *dp = (((((png_uint_32)(*sp) << 8) | * (png_uint_32)(*(sp + 1))) * 255 + 127) * / (png_uint_32)65535L; * * GRR: no, I think this is what it really should be: * *dp = (((((png_uint_32)(*sp) << 8) | * (png_uint_32)(*(sp + 1))) + 128L) * / (png_uint_32)257L; * * GRR: here's the exact calculation with shifts: * temp = (((png_uint_32)(*sp) << 8) | * (png_uint_32)(*(sp + 1))) + 128L; * *dp = (temp - (temp >> 8)) >> 8; * * Approximate calculation with shift/add instead of multiply/divide: * *dp = ((((png_uint_32)(*sp) << 8) | * (png_uint_32)((int)(*(sp + 1)) - *sp)) + 128) >> 8; * * What we actually do to avoid extra shifting and conversion: */ *dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0); #else /* Simply discard the low order byte */ *dp = *sp; #endif } row_info->bit_depth = 8; row_info->pixel_depth = (png_byte)(8 * row_info->channels); row_info->rowbytes = row_info->width * row_info->channels; } } #endif #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED void /* PRIVATE */ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) { png_debug(1, "in png_do_read_swap_alpha"); { png_uint_32 row_width = row_info->width; if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { /* This converts from RGBA to ARGB */ if (row_info->bit_depth == 8) { png_bytep sp = row + row_info->rowbytes; png_bytep dp = sp; png_byte save; png_uint_32 i; for (i = 0; i < row_width; i++) { save = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = save; } } /* This converts from RRGGBBAA to AARRGGBB */ else { png_bytep sp = row + row_info->rowbytes; png_bytep dp = sp; png_byte save[2]; png_uint_32 i; for (i = 0; i < row_width; i++) { save[0] = *(--sp); save[1] = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = save[0]; *(--dp) = save[1]; } } } else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { /* This converts from GA to AG */ if (row_info->bit_depth == 8) { png_bytep sp = row + row_info->rowbytes; png_bytep dp = sp; png_byte save; png_uint_32 i; for (i = 0; i < row_width; i++) { save = *(--sp); *(--dp) = *(--sp); *(--dp) = save; } } /* This converts from GGAA to AAGG */ else { png_bytep sp = row + row_info->rowbytes; png_bytep dp = sp; png_byte save[2]; png_uint_32 i; for (i = 0; i < row_width; i++) { save[0] = *(--sp); save[1] = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = save[0]; *(--dp) = save[1]; } } } } } #endif #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED void /* PRIVATE */ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row) { png_debug(1, "in png_do_read_invert_alpha"); { png_uint_32 row_width = row_info->width; if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { /* This inverts the alpha channel in RGBA */ if (row_info->bit_depth == 8) { png_bytep sp = row + row_info->rowbytes; png_bytep dp = sp; png_uint_32 i; for (i = 0; i < row_width; i++) { *(--dp) = (png_byte)(255 - *(--sp)); /* This does nothing: *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); We can replace it with: */ sp-=3; dp=sp; } } /* This inverts the alpha channel in RRGGBBAA */ else { png_bytep sp = row + row_info->rowbytes; png_bytep dp = sp; png_uint_32 i; for (i = 0; i < row_width; i++) { *(--dp) = (png_byte)(255 - *(--sp)); *(--dp) = (png_byte)(255 - *(--sp)); /* This does nothing: *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); We can replace it with: */ sp-=6; dp=sp; } } } else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { /* This inverts the alpha channel in GA */ if (row_info->bit_depth == 8) { png_bytep sp = row + row_info->rowbytes; png_bytep dp = sp; png_uint_32 i; for (i = 0; i < row_width; i++) { *(--dp) = (png_byte)(255 - *(--sp)); *(--dp) = *(--sp); } } /* This inverts the alpha channel in GGAA */ else { png_bytep sp = row + row_info->rowbytes; png_bytep dp = sp; png_uint_32 i; for (i = 0; i < row_width; i++) { *(--dp) = (png_byte)(255 - *(--sp)); *(--dp) = (png_byte)(255 - *(--sp)); /* *(--dp) = *(--sp); *(--dp) = *(--sp); */ sp-=2; dp=sp; } } } } } #endif #ifdef PNG_READ_FILLER_SUPPORTED /* Add filler channel if we have RGB color */ void /* PRIVATE */ png_do_read_filler(png_row_infop row_info, png_bytep row, png_uint_32 filler, png_uint_32 flags) { png_uint_32 i; png_uint_32 row_width = row_info->width; png_byte hi_filler = (png_byte)((filler>>8) & 0xff); png_byte lo_filler = (png_byte)(filler & 0xff); png_debug(1, "in png_do_read_filler"); if ( row_info->color_type == PNG_COLOR_TYPE_GRAY) { if (row_info->bit_depth == 8) { /* This changes the data from G to GX */ if (flags & PNG_FLAG_FILLER_AFTER) { png_bytep sp = row + (png_size_t)row_width; png_bytep dp = sp + (png_size_t)row_width; for (i = 1; i < row_width; i++) { *(--dp) = lo_filler; *(--dp) = *(--sp); } *(--dp) = lo_filler; row_info->channels = 2; row_info->pixel_depth = 16; row_info->rowbytes = row_width * 2; } /* This changes the data from G to XG */ else { png_bytep sp = row + (png_size_t)row_width; png_bytep dp = sp + (png_size_t)row_width; for (i = 0; i < row_width; i++) { *(--dp) = *(--sp); *(--dp) = lo_filler; } row_info->channels = 2; row_info->pixel_depth = 16; row_info->rowbytes = row_width * 2; } } else if (row_info->bit_depth == 16) { /* This changes the data from GG to GGXX */ if (flags & PNG_FLAG_FILLER_AFTER) { png_bytep sp = row + (png_size_t)row_width * 2; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 1; i < row_width; i++) { *(--dp) = hi_filler; *(--dp) = lo_filler; *(--dp) = *(--sp); *(--dp) = *(--sp); } *(--dp) = hi_filler; *(--dp) = lo_filler; row_info->channels = 2; row_info->pixel_depth = 32; row_info->rowbytes = row_width * 4; } /* This changes the data from GG to XXGG */ else { png_bytep sp = row + (png_size_t)row_width * 2; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 0; i < row_width; i++) { *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = hi_filler; *(--dp) = lo_filler; } row_info->channels = 2; row_info->pixel_depth = 32; row_info->rowbytes = row_width * 4; } } } /* COLOR_TYPE == GRAY */ else if (row_info->color_type == PNG_COLOR_TYPE_RGB) { if (row_info->bit_depth == 8) { /* This changes the data from RGB to RGBX */ if (flags & PNG_FLAG_FILLER_AFTER) { png_bytep sp = row + (png_size_t)row_width * 3; png_bytep dp = sp + (png_size_t)row_width; for (i = 1; i < row_width; i++) { *(--dp) = lo_filler; *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); } *(--dp) = lo_filler; row_info->channels = 4; row_info->pixel_depth = 32; row_info->rowbytes = row_width * 4; } /* This changes the data from RGB to XRGB */ else { png_bytep sp = row + (png_size_t)row_width * 3; png_bytep dp = sp + (png_size_t)row_width; for (i = 0; i < row_width; i++) { *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = lo_filler; } row_info->channels = 4; row_info->pixel_depth = 32; row_info->rowbytes = row_width * 4; } } else if (row_info->bit_depth == 16) { /* This changes the data from RRGGBB to RRGGBBXX */ if (flags & PNG_FLAG_FILLER_AFTER) { png_bytep sp = row + (png_size_t)row_width * 6; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 1; i < row_width; i++) { *(--dp) = hi_filler; *(--dp) = lo_filler; *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); } *(--dp) = hi_filler; *(--dp) = lo_filler; row_info->channels = 4; row_info->pixel_depth = 64; row_info->rowbytes = row_width * 8; } /* This changes the data from RRGGBB to XXRRGGBB */ else { png_bytep sp = row + (png_size_t)row_width * 6; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 0; i < row_width; i++) { *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = *(--sp); *(--dp) = hi_filler; *(--dp) = lo_filler; } row_info->channels = 4; row_info->pixel_depth = 64; row_info->rowbytes = row_width * 8; } } } /* COLOR_TYPE == RGB */ } #endif #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED /* Expand grayscale files to RGB, with or without alpha */ void /* PRIVATE */ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) { png_uint_32 i; png_uint_32 row_width = row_info->width; png_debug(1, "in png_do_gray_to_rgb"); if (row_info->bit_depth >= 8 && !(row_info->color_type & PNG_COLOR_MASK_COLOR)) { if (row_info->color_type == PNG_COLOR_TYPE_GRAY) { if (row_info->bit_depth == 8) { png_bytep sp = row + (png_size_t)row_width - 1; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 0; i < row_width; i++) { *(dp--) = *sp; *(dp--) = *sp; *(dp--) = *(sp--); } } else { png_bytep sp = row + (png_size_t)row_width * 2 - 1; png_bytep dp = sp + (png_size_t)row_width * 4; for (i = 0; i < row_width; i++) { *(dp--) = *sp; *(dp--) = *(sp - 1); *(dp--) = *sp; *(dp--) = *(sp - 1); *(dp--) = *(sp--); *(dp--) = *(sp--); } } } else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { if (row_info->bit_depth == 8) { png_bytep sp = row + (png_size_t)row_width * 2 - 1; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 0; i < row_width; i++) { *(dp--) = *(sp--); *(dp--) = *sp; *(dp--) = *sp; *(dp--) = *(sp--); } } else { png_bytep sp = row + (png_size_t)row_width * 4 - 1; png_bytep dp = sp + (png_size_t)row_width * 4; for (i = 0; i < row_width; i++) { *(dp--) = *(sp--); *(dp--) = *(sp--); *(dp--) = *sp; *(dp--) = *(sp - 1); *(dp--) = *sp; *(dp--) = *(sp - 1); *(dp--) = *(sp--); *(dp--) = *(sp--); } } } row_info->channels += (png_byte)2; row_info->color_type |= PNG_COLOR_MASK_COLOR; row_info->pixel_depth = (png_byte)(row_info->channels * row_info->bit_depth); row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); } } #endif #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED /* Reduce RGB files to grayscale, with or without alpha * using the equation given in Poynton's ColorFAQ at * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008) * New link: * <http://www.poynton.com/notes/colour_and_gamma/> * Charles Poynton poynton at poynton.com * * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B * * We approximate this with * * Y = 0.21268 * R + 0.7151 * G + 0.07217 * B * * which can be expressed with integers as * * Y = (6969 * R + 23434 * G + 2365 * B)/32768 * * The calculation is to be done in a linear colorspace. * * Other integer coefficents can be used via png_set_rgb_to_gray(). */ int /* PRIVATE */ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) { png_uint_32 i; png_uint_32 row_width = row_info->width; int rgb_error = 0; png_debug(1, "in png_do_rgb_to_gray"); if ( (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"); 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; } } #ifdef 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_color, png_color_16p background #ifdef 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"); if (background != NULL && (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) || (row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_color))) { 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_color->gray) { *sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff); *sp |= (png_byte)(background->gray << shift); } if (!shift) { shift = 7; sp++; } else shift--; } break; } case 2: { #ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_table != NULL) { sp = row; shift = 6; for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x03) == trans_color->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_color->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: { #ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_table != NULL) { sp = row; shift = 4; for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x0f) == trans_color->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_color->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: { #ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_table != NULL) { sp = row; for (i = 0; i < row_width; i++, sp++) { if (*sp == trans_color->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_color->gray) { *sp = (png_byte)background->gray; } } } break; } case 16: { #ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_16 != NULL) { sp = row; for (i = 0; i < row_width; i++, sp += 2) { png_uint_16 v; v = (png_uint_16)(((*sp) << 8) + *(sp + 1)); if (v == trans_color->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_color->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) { #ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_table != NULL) { sp = row; for (i = 0; i < row_width; i++, sp += 3) { if (*sp == trans_color->red && *(sp + 1) == trans_color->green && *(sp + 2) == trans_color->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_color->red && *(sp + 1) == trans_color->green && *(sp + 2) == trans_color->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) */ { #ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_16 != NULL) { sp = row; for (i = 0; i < row_width; i++, sp += 6) { png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1)); png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3)); png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5)); if (r == trans_color->red && g == trans_color->green && b == trans_color->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_color->red && g == trans_color->green && b == trans_color->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) { #ifdef 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; } #ifdef 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) */ { #ifdef 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); } #ifdef 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); } #ifdef 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); } #ifdef 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); } #ifdef 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) { #ifdef 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) */ { #ifdef 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 #ifdef PNG_READ_GAMMA_SUPPORTED /* Gamma correct the image, avoiding the alpha channel. Make sure * you do this after you deal with the transparency issue on grayscale * or RGB images. If your bit depth is 8, use gamma_table, if it * is 16, use gamma_16_table and gamma_shift. Build these with * build_gamma_table(). */ void /* PRIVATE */ png_do_gamma(png_row_infop row_info, png_bytep row, png_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"); if ( ((row_info->bit_depth <= 8 && gamma_table != NULL) || (row_info->bit_depth == 16 && gamma_16_table != NULL))) { switch (row_info->color_type) { case PNG_COLOR_TYPE_RGB: { if (row_info->bit_depth == 8) { sp = row; for (i = 0; i < row_width; i++) { *sp = gamma_table[*sp]; sp++; *sp = gamma_table[*sp]; sp++; *sp = gamma_table[*sp]; sp++; } } else /* if (row_info->bit_depth == 16) */ { sp = row; for (i = 0; i < row_width; i++) { png_uint_16 v; v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; *sp = (png_byte)((v >> 8) & 0xff); *(sp + 1) = (png_byte)(v & 0xff); sp += 2; v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; *sp = (png_byte)((v >> 8) & 0xff); *(sp + 1) = (png_byte)(v & 0xff); sp += 2; v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; *sp = (png_byte)((v >> 8) & 0xff); *(sp + 1) = (png_byte)(v & 0xff); sp += 2; } } break; } case PNG_COLOR_TYPE_RGB_ALPHA: { if (row_info->bit_depth == 8) { sp = row; for (i = 0; i < row_width; i++) { *sp = gamma_table[*sp]; sp++; *sp = gamma_table[*sp]; sp++; *sp = gamma_table[*sp]; sp++; sp++; } } else /* if (row_info->bit_depth == 16) */ { sp = row; for (i = 0; i < row_width; i++) { png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; *sp = (png_byte)((v >> 8) & 0xff); *(sp + 1) = (png_byte)(v & 0xff); sp += 2; v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; *sp = (png_byte)((v >> 8) & 0xff); *(sp + 1) = (png_byte)(v & 0xff); sp += 2; v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; *sp = (png_byte)((v >> 8) & 0xff); *(sp + 1) = (png_byte)(v & 0xff); sp += 4; } } break; } case PNG_COLOR_TYPE_GRAY_ALPHA: { if (row_info->bit_depth == 8) { sp = row; for (i = 0; i < row_width; i++) { *sp = gamma_table[*sp]; sp += 2; } } else /* if (row_info->bit_depth == 16) */ { sp = row; for (i = 0; i < row_width; i++) { png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; *sp = (png_byte)((v >> 8) & 0xff); *(sp + 1) = (png_byte)(v & 0xff); sp += 4; } } break; } case PNG_COLOR_TYPE_GRAY: { if (row_info->bit_depth == 2) { sp = row; for (i = 0; i < row_width; i += 4) { int a = *sp & 0xc0; int b = *sp & 0x30; int c = *sp & 0x0c; int d = *sp & 0x03; *sp = (png_byte)( ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)]) ) & 0xc0)| ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)| ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)| ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) )); sp++; } } if (row_info->bit_depth == 4) { sp = row; for (i = 0; i < row_width; i += 2) { int msb = *sp & 0xf0; int lsb = *sp & 0x0f; *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0) | (((int)gamma_table[(lsb << 4) | lsb]) >> 4)); sp++; } } else if (row_info->bit_depth == 8) { sp = row; for (i = 0; i < row_width; i++) { *sp = gamma_table[*sp]; sp++; } } else if (row_info->bit_depth == 16) { sp = row; for (i = 0; i < row_width; i++) { png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; *sp = (png_byte)((v >> 8) & 0xff); *(sp + 1) = (png_byte)(v & 0xff); sp += 2; } } break; } } } } #endif #ifdef PNG_READ_EXPAND_SUPPORTED /* Expands a palette row to an RGB or RGBA row depending * upon whether you supply trans and num_trans. */ void /* PRIVATE */ png_do_expand_palette(png_row_infop row_info, png_bytep row, png_colorp palette, png_bytep trans_alpha, int num_trans) { int shift, value; png_bytep sp, dp; png_uint_32 i; png_uint_32 row_width=row_info->width; png_debug(1, "in png_do_expand_palette"); if ( row_info->color_type == PNG_COLOR_TYPE_PALETTE) { if (row_info->bit_depth < 8) { switch (row_info->bit_depth) { case 1: { sp = row + (png_size_t)((row_width - 1) >> 3); dp = row + (png_size_t)row_width - 1; shift = 7 - (int)((row_width + 7) & 0x07); for (i = 0; i < row_width; i++) { if ((*sp >> shift) & 0x01) *dp = 1; else *dp = 0; if (shift == 7) { shift = 0; sp--; } else shift++; dp--; } break; } case 2: { sp = row + (png_size_t)((row_width - 1) >> 2); dp = row + (png_size_t)row_width - 1; shift = (int)((3 - ((row_width + 3) & 0x03)) << 1); for (i = 0; i < row_width; i++) { value = (*sp >> shift) & 0x03; *dp = (png_byte)value; if (shift == 6) { shift = 0; sp--; } else shift += 2; dp--; } break; } case 4: { sp = row + (png_size_t)((row_width - 1) >> 1); dp = row + (png_size_t)row_width - 1; shift = (int)((row_width & 0x01) << 2); for (i = 0; i < row_width; i++) { value = (*sp >> shift) & 0x0f; *dp = (png_byte)value; if (shift == 4) { shift = 0; sp--; } else shift += 4; dp--; } break; } } row_info->bit_depth = 8; row_info->pixel_depth = 8; row_info->rowbytes = row_width; } switch (row_info->bit_depth) { case 8: { if (trans_alpha != 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_alpha[*sp]; *dp-- = palette[*sp].blue; *dp-- = palette[*sp].green; *dp-- = palette[*sp].red; sp--; } row_info->bit_depth = 8; row_info->pixel_depth = 32; row_info->rowbytes = row_width * 4; row_info->color_type = 6; row_info->channels = 4; } else { sp = row + (png_size_t)row_width - 1; dp = row + (png_size_t)(row_width * 3) - 1; for (i = 0; i < row_width; i++) { *dp-- = palette[*sp].blue; *dp-- = palette[*sp].green; *dp-- = palette[*sp].red; sp--; } row_info->bit_depth = 8; row_info->pixel_depth = 24; row_info->rowbytes = row_width * 3; row_info->color_type = 2; row_info->channels = 3; } 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"); { 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 #ifdef PNG_READ_QUANTIZE_SUPPORTED void /* PRIVATE */ png_do_quantize(png_row_infop row_info, png_bytep row, png_bytep palette_lookup, png_bytep quantize_lookup) { png_bytep sp, dp; png_uint_32 i; png_uint_32 row_width=row_info->width; png_debug(1, "in png_do_quantize"); { if (row_info->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_QUANTIZE_RED_BITS)) & ((1 << PNG_QUANTIZE_RED_BITS) - 1)) << (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) | (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) & ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) << (PNG_QUANTIZE_BLUE_BITS)) | ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) & ((1 << PNG_QUANTIZE_BLUE_BITS) - 1)); *dp++ = palette_lookup[p]; } row_info->color_type = PNG_COLOR_TYPE_PALETTE; row_info->channels = 1; row_info->pixel_depth = row_info->bit_depth; row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); } else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA && palette_lookup != NULL && 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_QUANTIZE_RED_BITS)) & ((1 << PNG_QUANTIZE_RED_BITS) - 1)) << (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) | (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) & ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) << (PNG_QUANTIZE_BLUE_BITS)) | ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) & ((1 << PNG_QUANTIZE_BLUE_BITS) - 1)); *dp++ = palette_lookup[p]; } row_info->color_type = PNG_COLOR_TYPE_PALETTE; row_info->channels = 1; row_info->pixel_depth = row_info->bit_depth; row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); } else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE && quantize_lookup && row_info->bit_depth == 8) { sp = row; for (i = 0; i < row_width; i++, sp++) { *sp = quantize_lookup[*sp]; } } } } #endif #ifdef PNG_FLOATING_POINT_SUPPORTED #ifdef 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. * * See the PNG extensions document for an integer algorithm for creating * the gamma tables. Maybe we will implement that here someday. * * We should only reach this point if * * the file_gamma is known (i.e., the gAMA or sRGB chunk is present, * or the application has provided a file_gamma) * * AND * { * the screen_gamma is known * * OR * * RGB_to_gray transformation is being performed * } * * AND * { * the screen_gamma is different from the reciprocal of the * file_gamma by more than the specified threshold * * OR * * a background color has been specified and the file_gamma * and screen_gamma are not 1.0, within the specified threshold. * } */ void /* PRIVATE */ png_build_gamma_table(png_structp png_ptr, png_byte bit_depth) { png_debug(1, "in png_build_gamma_table"); if (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_calloc(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_calloc(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_calloc(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 #ifdef PNG_MNG_FEATURES_SUPPORTED /* Undoes intrapixel differencing */ void /* PRIVATE */ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) { png_debug(1, "in png_do_read_intrapixel"); if ( (row_info->color_type & PNG_COLOR_MASK_COLOR)) { int bytes_per_pixel; png_uint_32 row_width = row_info->width; if (row_info->bit_depth == 8) { png_bytep rp; png_uint_32 i; if (row_info->color_type == PNG_COLOR_TYPE_RGB) bytes_per_pixel = 3; else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) bytes_per_pixel = 4; else return; for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) { *(rp) = (png_byte)((256 + *rp + *(rp+1))&0xff); *(rp+2) = (png_byte)((256 + *(rp+2) + *(rp+1))&0xff); } } else if (row_info->bit_depth == 16) { png_bytep rp; png_uint_32 i; if (row_info->color_type == PNG_COLOR_TYPE_RGB) bytes_per_pixel = 6; else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) bytes_per_pixel = 8; else return; for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) { png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1); png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3); png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5); png_uint_32 red = (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 */
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