| |
| /* pngrtran.c - transforms the data in a row for png readers |
| |
| libpng 1.0 beta 1 - version 0.71 |
| For conditions of distribution and use, see copyright notice in png.h |
| Copyright (c) 1995 Guy Eric Schalnat, Group 42, Inc. |
| June 26, 1995 |
| */ |
| |
| #define PNG_INTERNAL |
| #include "png.h" |
| |
| /* handle alpha and tRNS via a background color */ |
| void |
| png_set_background(png_struct *png_ptr, |
| png_color_16 *background_color, int background_gamma_code, |
| int need_expand, float background_gamma) |
| { |
| png_ptr->transformations |= PNG_BACKGROUND; |
| memcpy(&(png_ptr->background), background_color, |
| sizeof(png_color_16)); |
| png_ptr->background_gamma = background_gamma; |
| png_ptr->background_gamma_type = background_gamma_code; |
| png_ptr->background_expand = need_expand; |
| } |
| |
| /* strip 16 bit depth files to 8 bit depth */ |
| void |
| png_set_strip_16(png_struct *png_ptr) |
| { |
| png_ptr->transformations |= PNG_16_TO_8; |
| } |
| |
| /* dither file to 8 bit. Supply a palette, the current number |
| of elements in the palette, the maximum number of elements |
| allowed, and a histogram, if possible. If the current number |
| is greater then the maximum number, the palette will be |
| modified to fit in the maximum number */ |
| |
| typedef struct dsort_struct |
| { |
| struct dsort_struct *next; |
| png_byte left; |
| png_byte right; |
| } dsort; |
| |
| void |
| png_set_dither(png_struct *png_ptr, png_color *palette, |
| int num_palette, int maximum_colors, png_uint_16 *histogram, |
| int full_dither) |
| { |
| png_ptr->transformations |= PNG_DITHER; |
| |
| if (!full_dither) |
| { |
| int i; |
| |
| png_ptr->dither_index = png_malloc(png_ptr, |
| num_palette * sizeof (png_byte)); |
| for (i = 0; i < num_palette; i++) |
| png_ptr->dither_index[i] = i; |
| } |
| |
| if (num_palette > maximum_colors) |
| { |
| if (histogram) |
| { |
| /* this is easy enough, just throw out the least used colors. |
| perhaps not the best solution, but good enough */ |
| |
| int i; |
| png_byte *sort; |
| |
| /* initialize an array to sort colors */ |
| sort = (png_byte *)png_malloc(png_ptr, num_palette * sizeof (png_byte)); |
| |
| /* initialize the sort array */ |
| for (i = 0; i < num_palette; i++) |
| sort[i] = 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[sort[j]] < histogram[sort[j + 1]]) |
| { |
| png_byte t; |
| |
| t = sort[j]; |
| sort[j] = sort[j + 1]; |
| sort[j + 1] = t; |
| done = 0; |
| } |
| } |
| if (done) |
| break; |
| } |
| |
| /* swap the palette around, and set up a table, if necessary */ |
| if (full_dither) |
| { |
| int j; |
| |
| /* put all the useful colors within the max, but don't |
| move the others */ |
| j = num_palette; |
| for (i = 0; i < maximum_colors; i++) |
| { |
| if (sort[i] >= maximum_colors) |
| { |
| do |
| j--; |
| while (sort[j] >= maximum_colors); |
| palette[i] = palette[j]; |
| } |
| } |
| } |
| else |
| { |
| int j; |
| |
| /* move all the used colors inside the max limit, and |
| develop a translation table */ |
| j = num_palette; |
| for (i = 0; i < maximum_colors; i++) |
| { |
| /* only move the colors we need to */ |
| if (sort[i] >= maximum_colors) |
| { |
| png_color tmp_color; |
| |
| do |
| j--; |
| while (sort[j] >= maximum_colors); |
| |
| tmp_color = palette[j]; |
| palette[j] = palette[i]; |
| palette[i] = tmp_color; |
| /* indicate where the color went */ |
| png_ptr->dither_index[j] = i; |
| png_ptr->dither_index[i] = j; |
| } |
| } |
| /* find closest color for those colors we are not |
| using */ |
| for (i = 0; i < num_palette; i++) |
| { |
| if (png_ptr->dither_index[i] >= maximum_colors) |
| { |
| int min_d, j, min_j, index; |
| |
| /* find the closest color to one we threw out */ |
| index = png_ptr->dither_index[i]; |
| min_d = PNG_COLOR_DIST(palette[index], |
| palette[0]); |
| min_j = 0; |
| for (j = 1; j < maximum_colors; j++) |
| { |
| int d; |
| |
| d = PNG_COLOR_DIST(palette[index], |
| palette[j]); |
| |
| if (d < min_d) |
| { |
| min_d = d; |
| min_j = j; |
| } |
| } |
| /* point to closest color */ |
| png_ptr->dither_index[i] = min_j; |
| } |
| } |
| } |
| png_free(png_ptr, sort); |
| } |
| 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). |
| */ |
| int i; |
| int max_d; |
| int num_new_palette; |
| dsort **hash; |
| png_byte *index_to_palette; |
| /* where the original index currently is in the palette */ |
| png_byte *palette_to_index; |
| /* which original index points to this palette color */ |
| |
| /* initialize palette index arrays */ |
| index_to_palette = (png_byte *)png_malloc(png_ptr, |
| num_palette * sizeof (png_byte)); |
| palette_to_index = (png_byte *)png_malloc(png_ptr, |
| num_palette * sizeof (png_byte)); |
| |
| /* initialize the sort array */ |
| for (i = 0; i < num_palette; i++) |
| { |
| index_to_palette[i] = i; |
| palette_to_index[i] = i; |
| } |
| |
| hash = (dsort **)png_malloc(png_ptr, 769 * sizeof (dsort *)); |
| for (i = 0; i < 769; i++) |
| hash[i] = (dsort *)0; |
| /* memset(hash, 0, 769 * sizeof (dsort *)); */ |
| |
| 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) |
| { |
| dsort *t; |
| |
| t = png_malloc(png_ptr, sizeof (dsort)); |
| t->next = hash[d]; |
| t->left = i; |
| t->right = j; |
| hash[d] = t; |
| } |
| } |
| } |
| |
| for (i = 0; i <= max_d; i++) |
| { |
| if (hash[i]) |
| { |
| dsort *p; |
| |
| for (p = hash[i]; p; p = p->next) |
| { |
| if (index_to_palette[p->left] < num_new_palette && |
| index_to_palette[p->right] < num_new_palette) |
| { |
| int j, next_j; |
| |
| if (num_new_palette & 1) |
| { |
| j = p->left; |
| next_j = p->right; |
| } |
| else |
| { |
| j = p->right; |
| next_j = p->left; |
| } |
| |
| num_new_palette--; |
| palette[index_to_palette[j]] = |
| palette[num_new_palette]; |
| if (!full_dither) |
| { |
| int k; |
| |
| for (k = 0; k < num_palette; k++) |
| { |
| if (png_ptr->dither_index[k] == |
| index_to_palette[j]) |
| png_ptr->dither_index[k] = |
| index_to_palette[next_j]; |
| if (png_ptr->dither_index[k] == |
| num_new_palette) |
| png_ptr->dither_index[k] = |
| index_to_palette[j]; |
| } |
| } |
| |
| index_to_palette[palette_to_index[num_new_palette]] = |
| index_to_palette[j]; |
| palette_to_index[index_to_palette[j]] = |
| palette_to_index[num_new_palette]; |
| |
| index_to_palette[j] = num_new_palette; |
| palette_to_index[num_new_palette] = j; |
| } |
| if (num_new_palette <= maximum_colors) |
| break; |
| } |
| if (num_new_palette <= maximum_colors) |
| break; |
| } |
| } |
| |
| for (i = 0; i < 769; i++) |
| { |
| if (hash[i]) |
| { |
| dsort *p; |
| |
| p = hash[i]; |
| while (p) |
| { |
| dsort *t; |
| |
| 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, palette_to_index); |
| png_free(png_ptr, index_to_palette); |
| } |
| num_palette = maximum_colors; |
| } |
| if (!(png_ptr->palette)) |
| { |
| png_ptr->palette = palette; |
| png_ptr->user_palette = 1; |
| } |
| png_ptr->num_palette = num_palette; |
| |
| if (full_dither) |
| { |
| int i; |
| int total_bits, num_red, num_green, num_blue; |
| png_uint_32 num_entries; |
| png_byte *distance; |
| |
| total_bits = PNG_DITHER_RED_BITS + PNG_DITHER_GREEN_BITS + |
| PNG_DITHER_BLUE_BITS; |
| |
| num_red = (1 << PNG_DITHER_RED_BITS); |
| num_green = (1 << PNG_DITHER_GREEN_BITS); |
| num_blue = (1 << PNG_DITHER_BLUE_BITS); |
| num_entries = ((png_uint_32)1 << total_bits); |
| |
| png_ptr->palette_lookup = (png_byte *)png_large_malloc(png_ptr, |
| (png_size_t)num_entries * sizeof (png_byte)); |
| |
| memset(png_ptr->palette_lookup, 0, (png_size_t)num_entries * sizeof (png_byte)); |
| |
| distance = (png_byte *)png_large_malloc(png_ptr, |
| (png_size_t)num_entries * sizeof (png_byte)); |
| |
| memset(distance, 0xff, (png_size_t)num_entries * sizeof (png_byte)); |
| |
| for (i = 0; i < num_palette; i++) |
| { |
| int r, g, b, ir, ig, ib; |
| |
| r = (palette[i].red >> (8 - PNG_DITHER_RED_BITS)); |
| g = (palette[i].green >> (8 - PNG_DITHER_GREEN_BITS)); |
| b = (palette[i].blue >> (8 - PNG_DITHER_BLUE_BITS)); |
| |
| for (ir = 0; ir < num_red; ir++) |
| { |
| int dr, index_r; |
| |
| dr = abs(ir - r); |
| index_r = (ir << (PNG_DITHER_BLUE_BITS + PNG_DITHER_GREEN_BITS)); |
| for (ig = 0; ig < num_green; ig++) |
| { |
| int dg, dt, dm, index_g; |
| |
| dg = abs(ig - g); |
| dt = dr + dg; |
| dm = ((dr > dg) ? dr : dg); |
| index_g = index_r | (ig << PNG_DITHER_BLUE_BITS); |
| for (ib = 0; ib < num_blue; ib++) |
| { |
| int index, db, dmax, d; |
| |
| index = index_g | ib; |
| db = abs(ib - b); |
| dmax = ((dm > db) ? dm : db); |
| d = dmax + dt + db; |
| |
| if (d < distance[index]) |
| { |
| distance[index] = d; |
| png_ptr->palette_lookup[index] = i; |
| } |
| } |
| } |
| } |
| } |
| |
| png_large_free(png_ptr, distance); |
| } |
| #ifdef oldway |
| d = TABLE_COLOR_DISTANCE(index, palette[i]); |
| dt = TABLE_DISTANCE(index); |
| if (d < dt) |
| png_ptr->palette_lookup[index] = i; |
| |
| for (ir = r + 1, index2 = index; ir < num_red; ir++) |
| { |
| index2 += (1 << (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)); |
| d = RGB_COLOR_DISTANCE(r, g, b, palette[i]); |
| dt = TABLE_DISTANCE(index2); |
| if (d < dt) |
| png_ptr->palette_lookup[index2] = i; |
| else |
| break; |
| } |
| |
| |
| |
| i = 0; |
| for (ir = 0; ir < num_red; ir++) |
| { |
| r = (ir * 255) / (num_red - 1); |
| for (ig = 0; ig < num_green; ig++) |
| { |
| g = (ig * 255) / (num_green - 1); |
| for (ib = 0; ib < num_blue; ib++) |
| { |
| int min_d, j, k, d; |
| |
| b = (ib * 255) / (num_blue - 1); |
| min_d = 1024; |
| k = 0; |
| for (j = 0; j < png_ptr->num_palette; j++) |
| { |
| d = abs(r - (int)png_ptr->palette[j].red) + |
| abs(g - (int)png_ptr->palette[j].green) + |
| abs(b - (int)png_ptr->palette[j].blue); |
| if (d < min_d) |
| { |
| min_d = d; |
| k = j; |
| } |
| } |
| png_ptr->palette_lookup[i++] = k; |
| } |
| } |
| } |
| #endif |
| } |
| |
| /* transform the image from the file_gamma to the screen_gamma */ |
| void |
| png_set_gamma(png_struct *png_ptr, float screen_gamma, |
| float file_gamma) |
| { |
| png_ptr->transformations |= PNG_GAMMA; |
| png_ptr->gamma = file_gamma; |
| png_ptr->display_gamma = screen_gamma; |
| } |
| |
| /* expand paletted images to rgb, expand grayscale images of |
| less then 8 bit depth to 8 bit depth, and expand tRNS chunks |
| to alpha channels */ |
| void |
| png_set_expand(png_struct *png_ptr) |
| { |
| png_ptr->transformations |= PNG_EXPAND; |
| } |
| |
| void |
| png_set_gray_to_rgb(png_struct *png_ptr) |
| { |
| png_ptr->transformations |= PNG_GRAY_TO_RGB; |
| } |
| |
| /* initialize everything needed for the read. This includes modifying |
| the palette */ |
| void |
| png_init_read_transformations(png_struct *png_ptr) |
| { |
| int color_type; |
| |
| color_type = png_ptr->color_type; |
| |
| if (png_ptr->transformations & PNG_EXPAND) |
| { |
| if (color_type == PNG_COLOR_TYPE_GRAY && |
| png_ptr->bit_depth < 8 && |
| (!(png_ptr->transformations & PNG_BACKGROUND) || |
| png_ptr->background_expand)) |
| { |
| /* expand background chunk. While this may not be |
| the fastest way to do this, it only happens once |
| per file. */ |
| switch (png_ptr->bit_depth) |
| { |
| case 1: |
| png_ptr->background.gray *= 0xff; |
| break; |
| case 2: |
| png_ptr->background.gray *= 0x55; |
| break; |
| case 4: |
| png_ptr->background.gray *= 0x11; |
| break; |
| } |
| } |
| if (color_type == PNG_COLOR_TYPE_PALETTE && |
| (png_ptr->transformations & PNG_BACKGROUND) && |
| png_ptr->background_expand) |
| { |
| /* expand background chunk */ |
| 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; |
| color_type = PNG_COLOR_TYPE_RGB; |
| } |
| } |
| |
| png_ptr->background_1 = png_ptr->background; |
| if (png_ptr->transformations & PNG_GAMMA) |
| { |
| png_build_gamma_table(png_ptr); |
| if ((png_ptr->transformations & PNG_BACKGROUND) && |
| (color_type != PNG_COLOR_TYPE_PALETTE)) |
| { |
| if (png_ptr->background_gamma_type != PNG_BACKGROUND_GAMMA_UNKNOWN) |
| { |
| double g, gs, m; |
| |
| m = (double)((png_uint_32)1 << png_ptr->bit_depth); |
| g = 1.0; |
| gs = 1.0; |
| |
| switch (png_ptr->background_gamma_type) |
| { |
| case PNG_BACKGROUND_GAMMA_SCREEN: |
| g = (png_ptr->display_gamma); |
| gs = 1.0; |
| break; |
| case PNG_BACKGROUND_GAMMA_FILE: |
| g = 1.0 / (png_ptr->gamma); |
| gs = 1.0 / (png_ptr->gamma * png_ptr->display_gamma); |
| break; |
| case PNG_BACKGROUND_GAMMA_UNIQUE: |
| g = 1.0 / (png_ptr->background_gamma); |
| gs = 1.0 / (png_ptr->background_gamma * |
| png_ptr->display_gamma); |
| break; |
| } |
| |
| if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) |
| { |
| 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 |
| { |
| 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); |
| } |
| } |
| } |
| } |
| } |
| |
| /* 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 |
| png_do_read_transformations(png_struct *png_ptr) |
| { |
| if ((png_ptr->transformations & PNG_EXPAND) && |
| png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| png_ptr->palette, png_ptr->trans, png_ptr->num_trans); |
| } |
| else if (png_ptr->transformations & PNG_EXPAND) |
| { |
| if (png_ptr->num_trans) |
| png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| &(png_ptr->trans_values)); |
| else |
| png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| NULL); |
| } |
| if (png_ptr->transformations & PNG_BACKGROUND) |
| png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| &(png_ptr->trans_values), &(png_ptr->background), |
| &(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); |
| else if (png_ptr->transformations & PNG_GAMMA) |
| 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); |
| if (png_ptr->transformations & PNG_16_TO_8) |
| png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| if (png_ptr->transformations & PNG_DITHER) |
| png_do_dither(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| png_ptr->palette_lookup, png_ptr->dither_index); |
| if (png_ptr->transformations & PNG_INVERT_MONO) |
| png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| if (png_ptr->transformations & PNG_SHIFT) |
| png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| &(png_ptr->shift)); |
| if (png_ptr->transformations & PNG_PACK) |
| png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| if (png_ptr->transformations & PNG_BGR) |
| png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| if (png_ptr->transformations & PNG_GRAY_TO_RGB) |
| png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| if (png_ptr->transformations & PNG_SWAP_BYTES) |
| png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| if (png_ptr->transformations & PNG_RGBA) |
| png_do_read_rgbx(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| if (png_ptr->transformations & PNG_XRGB) |
| png_do_read_xrgb(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| } |
| |
| /* 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 |
| png_do_unpack(png_row_info *row_info, png_byte *row) |
| { |
| if (row && row_info && row_info->bit_depth < 8) |
| { |
| switch (row_info->bit_depth) |
| { |
| case 1: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)((row_info->width - 1) >> 3); |
| dp = row + (png_size_t)row_info->width - 1; |
| shift = 7 - (int)((row_info->width + 7) & 7); |
| for (i = 0; i < row_info->width; i++) |
| { |
| *dp = (*sp >> shift) & 0x1; |
| if (shift == 7) |
| { |
| shift = 0; |
| sp--; |
| } |
| else |
| shift++; |
| |
| dp--; |
| } |
| break; |
| } |
| case 2: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)((row_info->width - 1) >> 2); |
| dp = row + (png_size_t)row_info->width - 1; |
| shift = (int)((3 - ((row_info->width + 3) & 3)) << 1); |
| for (i = 0; i < row_info->width; i++) |
| { |
| *dp = (*sp >> shift) & 0x3; |
| if (shift == 6) |
| { |
| shift = 0; |
| sp--; |
| } |
| else |
| shift += 2; |
| |
| dp--; |
| } |
| break; |
| } |
| case 4: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)((row_info->width - 1) >> 1); |
| dp = row + (png_size_t)row_info->width - 1; |
| shift = (int)((1 - ((row_info->width + 1) & 1)) << 4); |
| for (i = 0; i < row_info->width; i++) |
| { |
| *dp = (*sp >> shift) & 0xf; |
| if (shift == 4) |
| { |
| shift = 0; |
| sp--; |
| } |
| else |
| shift = 4; |
| |
| dp--; |
| } |
| break; |
| } |
| } |
| row_info->bit_depth = 8; |
| row_info->pixel_depth = 8 * row_info->channels; |
| row_info->rowbytes = row_info->width * row_info->channels; |
| } |
| } |
| |
| /* 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 |
| png_do_unshift(png_row_info *row_info, png_byte *row, |
| png_color_8 *sig_bits) |
| { |
| if (row && row_info && sig_bits) |
| { |
| int shift[4]; |
| int channels; |
| |
| channels = 0; |
| 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; |
| } |
| |
| switch (row_info->bit_depth) |
| { |
| case 2: |
| { |
| png_byte *bp; |
| png_uint_32 i; |
| |
| for (bp = row, i = 0; |
| i < row_info->rowbytes; |
| i++, bp++) |
| { |
| *bp >>= 1; |
| *bp &= 0x55; |
| } |
| break; |
| } |
| case 4: |
| { |
| png_byte *bp, mask; |
| png_uint_32 i; |
| |
| mask = (png_byte)(((int)0xf0 >> shift[0]) & (int)0xf0) | |
| ((int)0xf >> shift[0]); |
| for (bp = row, i = 0; |
| i < row_info->rowbytes; |
| i++, bp++) |
| { |
| *bp >>= shift[0]; |
| *bp &= mask; |
| } |
| break; |
| } |
| case 8: |
| { |
| png_byte *bp; |
| png_uint_32 i; |
| |
| for (bp = row, i = 0; |
| i < row_info->width; i++) |
| { |
| int c; |
| |
| for (c = 0; c < row_info->channels; c++, bp++) |
| { |
| *bp >>= shift[c]; |
| } |
| } |
| break; |
| } |
| case 16: |
| { |
| png_byte *bp; |
| png_uint_16 value; |
| png_uint_32 i; |
| |
| for (bp = row, i = 0; |
| i < row_info->width; i++) |
| { |
| int c; |
| |
| for (c = 0; c < row_info->channels; c++, bp += 2) |
| { |
| value = (*bp << 8) + *(bp + 1); |
| value >>= shift[c]; |
| *bp = value >> 8; |
| *(bp + 1) = value & 0xff; |
| } |
| } |
| break; |
| } |
| } |
| } |
| } |
| |
| /* chop rows of bit depth 16 down to 8 */ |
| void |
| png_do_chop(png_row_info *row_info, png_byte *row) |
| { |
| if (row && row_info && row_info->bit_depth == 16) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| sp = row + 2; |
| dp = row + 1; |
| for (i = 1; i < row_info->width * row_info->channels; i++) |
| { |
| *dp = *sp; |
| sp += 2; |
| dp++; |
| } |
| row_info->bit_depth = 8; |
| row_info->pixel_depth = 8 * row_info->channels; |
| row_info->rowbytes = row_info->width * row_info->channels; |
| } |
| } |
| |
| /* add filler byte after rgb */ |
| void |
| png_do_read_rgbx(png_row_info *row_info, png_byte *row) |
| { |
| if (row && row_info && row_info->color_type == 2 && |
| row_info->bit_depth == 8) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 1, sp = row + (png_size_t)row_info->width * 3, |
| dp = row + (png_size_t)row_info->width * 4; |
| i < row_info->width; |
| i++) |
| { |
| *(--dp) = 0xff; |
| *(--dp) = *(--sp); |
| *(--dp) = *(--sp); |
| *(--dp) = *(--sp); |
| } |
| *(--dp) = 0xff; |
| row_info->channels = 4; |
| row_info->pixel_depth = 32; |
| row_info->rowbytes = row_info->width * 4; |
| } |
| } |
| |
| /* add filler byte before rgb */ |
| void |
| png_do_read_xrgb(png_row_info *row_info, png_byte *row) |
| { |
| if (row && row_info && row_info->color_type == 2 && |
| row_info->bit_depth == 8) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row + (png_size_t)row_info->width * 3, |
| dp = row + (png_size_t)row_info->width * 4; |
| i < row_info->width; |
| i++) |
| { |
| *(--dp) = *(--sp); |
| *(--dp) = *(--sp); |
| *(--dp) = *(--sp); |
| *(--dp) = 0xff; |
| } |
| row_info->channels = 4; |
| row_info->pixel_depth = 32; |
| row_info->rowbytes = row_info->width * 4; |
| } |
| } |
| |
| /* expand grayscale files to rgb, with or without alpha */ |
| void |
| png_do_gray_to_rgb(png_row_info *row_info, png_byte *row) |
| { |
| if (row && row_info && 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_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row + (png_size_t)row_info->width - 1, |
| dp = row + (png_size_t)row_info->width * 3 - 1; |
| i < row_info->width; |
| i++) |
| { |
| *(dp--) = *sp; |
| *(dp--) = *sp; |
| *(dp--) = *sp; |
| sp--; |
| } |
| } |
| else |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row + (png_size_t)row_info->width * 2 - 1, |
| dp = row + (png_size_t)row_info->width * 6 - 1; |
| i < row_info->width; |
| i++) |
| { |
| *(dp--) = *sp; |
| *(dp--) = *(sp - 1); |
| *(dp--) = *sp; |
| *(dp--) = *(sp - 1); |
| *(dp--) = *sp; |
| *(dp--) = *(sp - 1); |
| sp--; |
| sp--; |
| } |
| } |
| } |
| else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
| { |
| if (row_info->bit_depth == 8) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row + (png_size_t)row_info->width * 2 - 1, |
| dp = row + (png_size_t)row_info->width * 4 - 1; |
| i < row_info->width; |
| i++) |
| { |
| *(dp--) = *(sp--); |
| *(dp--) = *sp; |
| *(dp--) = *sp; |
| *(dp--) = *sp; |
| sp--; |
| } |
| } |
| else |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row + (png_size_t)row_info->width * 4 - 1, |
| dp = row + (png_size_t)row_info->width * 8 - 1; |
| i < row_info->width; |
| i++) |
| { |
| *(dp--) = *(sp--); |
| *(dp--) = *(sp--); |
| *(dp--) = *sp; |
| *(dp--) = *(sp - 1); |
| *(dp--) = *sp; |
| *(dp--) = *(sp - 1); |
| *(dp--) = *sp; |
| *(dp--) = *(sp - 1); |
| sp--; |
| sp--; |
| } |
| } |
| } |
| row_info->channels += 2; |
| row_info->color_type |= PNG_COLOR_MASK_COLOR; |
| row_info->pixel_depth = row_info->channels * row_info->bit_depth; |
| row_info->rowbytes = ((row_info->width * |
| row_info->pixel_depth + 7) >> 3); |
| } |
| } |
| |
| /* 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 |
| png_build_grayscale_palette(int bit_depth, png_color *palette) |
| { |
| int num_palette; |
| int color_inc; |
| int i; |
| int v; |
| |
| if (!palette) |
| 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; |
| break; |
| } |
| |
| for (i = 0, v = 0; i < num_palette; i++, v += color_inc) |
| { |
| palette[i].red = v; |
| palette[i].green = v; |
| palette[i].blue = v; |
| } |
| } |
| |
| void |
| png_correct_palette(png_struct *png_ptr, png_color *palette, |
| int num_palette) |
| { |
| if ((png_ptr->transformations & (PNG_GAMMA)) && |
| (png_ptr->transformations & (PNG_BACKGROUND))) |
| { |
| if (png_ptr->color_type == 3) |
| { |
| int i; |
| png_color back, back_1; |
| |
| back.red = png_ptr->gamma_table[png_ptr->palette[ |
| png_ptr->background.index].red]; |
| back.green = png_ptr->gamma_table[png_ptr->palette[ |
| png_ptr->background.index].green]; |
| back.blue = png_ptr->gamma_table[png_ptr->palette[ |
| png_ptr->background.index].blue]; |
| |
| back_1.red = png_ptr->gamma_to_1[png_ptr->palette[ |
| png_ptr->background.index].red]; |
| back_1.green = png_ptr->gamma_to_1[png_ptr->palette[ |
| png_ptr->background.index].green]; |
| back_1.blue = png_ptr->gamma_to_1[png_ptr->palette[ |
| png_ptr->background.index].blue]; |
| |
| for (i = 0; i < num_palette; i++) |
| { |
| if (i < (int)png_ptr->num_trans && |
| png_ptr->trans[i] == 0) |
| { |
| palette[i] = back; |
| } |
| else if (i < (int)png_ptr->num_trans && |
| png_ptr->trans[i] != 0xff) |
| { |
| int v; |
| |
| v = png_ptr->gamma_to_1[png_ptr->palette[i].red]; |
| v = (int)(((png_uint_32)(v) * |
| (png_uint_32)(png_ptr->trans[i]) + |
| (png_uint_32)(back_1.red) * |
| (png_uint_32)(255 - png_ptr->trans[i]) + |
| 127) / 255); |
| palette[i].red = png_ptr->gamma_from_1[v]; |
| |
| v = png_ptr->gamma_to_1[png_ptr->palette[i].green]; |
| v = (int)(((png_uint_32)(v) * |
| (png_uint_32)(png_ptr->trans[i]) + |
| (png_uint_32)(back_1.green) * |
| (png_uint_32)(255 - png_ptr->trans[i]) + |
| 127) / 255); |
| palette[i].green = png_ptr->gamma_from_1[v]; |
| |
| v = png_ptr->gamma_to_1[png_ptr->palette[i].blue]; |
| v = (int)(((png_uint_32)(v) * |
| (png_uint_32)(png_ptr->trans[i]) + |
| (png_uint_32)(back_1.blue) * |
| (png_uint_32)(255 - png_ptr->trans[i]) + |
| 127) / 255); |
| palette[i].blue = png_ptr->gamma_from_1[v]; |
| } |
| else |
| { |
| palette[i].red = png_ptr->gamma_table[palette[i].red]; |
| palette[i].green = png_ptr->gamma_table[palette[i].green]; |
| palette[i].blue = png_ptr->gamma_table[palette[i].blue]; |
| } |
| } |
| } |
| else |
| { |
| int i, back; |
| |
| back = png_ptr->gamma_table[png_ptr->background.gray]; |
| |
| for (i = 0; i < num_palette; i++) |
| { |
| if (palette[i].red == png_ptr->trans_values.gray) |
| { |
| palette[i].red = back; |
| palette[i].green = back; |
| palette[i].blue = back; |
| } |
| else |
| { |
| palette[i].red = png_ptr->gamma_table[palette[i].red]; |
| palette[i].green = png_ptr->gamma_table[palette[i].green]; |
| palette[i].blue = png_ptr->gamma_table[palette[i].blue]; |
| } |
| } |
| } |
| } |
| else if (png_ptr->transformations & (PNG_GAMMA)) |
| { |
| int i; |
| |
| for (i = 0; i < num_palette; i++) |
| { |
| palette[i].red = png_ptr->gamma_table[palette[i].red]; |
| palette[i].green = png_ptr->gamma_table[palette[i].green]; |
| palette[i].blue = png_ptr->gamma_table[palette[i].blue]; |
| } |
| } |
| else if (png_ptr->transformations & (PNG_BACKGROUND)) |
| { |
| if (png_ptr->color_type == 3) |
| { |
| int i; |
| png_byte br, bg, bb; |
| |
| br = palette[png_ptr->background.index].red; |
| bg = palette[png_ptr->background.index].green; |
| bb = palette[png_ptr->background.index].blue; |
| |
| for (i = 0; i < num_palette; i++) |
| { |
| if (i >= (int)png_ptr->num_trans || |
| png_ptr->trans[i] == 0) |
| { |
| palette[i].red = br; |
| palette[i].green = bg; |
| palette[i].blue = bb; |
| } |
| else if (i < (int)png_ptr->num_trans || |
| png_ptr->trans[i] != 0xff) |
| { |
| palette[i].red = (png_byte)(( |
| (png_uint_32)(png_ptr->palette[i].red) * |
| (png_uint_32)(png_ptr->trans[i]) + |
| (png_uint_32)(br) * |
| (png_uint_32)(255 - png_ptr->trans[i]) + |
| 127) / 255); |
| palette[i].green = (png_byte)(( |
| (png_uint_32)(png_ptr->palette[i].green) * |
| (png_uint_32)(png_ptr->trans[i]) + |
| (png_uint_32)(bg) * |
| (png_uint_32)(255 - png_ptr->trans[i]) + |
| 127) / 255); |
| palette[i].blue = (png_byte)(( |
| (png_uint_32)(png_ptr->palette[i].blue) * |
| (png_uint_32)(png_ptr->trans[i]) + |
| (png_uint_32)(bb) * |
| (png_uint_32)(255 - png_ptr->trans[i]) + |
| 127) / 255); |
| } |
| } |
| } |
| else /* assume grayscale palette (what else could it be?) */ |
| { |
| int i; |
| |
| for (i = 0; i < num_palette; i++) |
| { |
| if (i == (int)png_ptr->trans_values.gray) |
| { |
| palette[i].red = (png_byte)png_ptr->background.gray; |
| palette[i].green = (png_byte)png_ptr->background.gray; |
| palette[i].blue = (png_byte)png_ptr->background.gray; |
| } |
| } |
| } |
| } |
| } |
| |
| /* replace any alpha or transparency with the supplied background color. |
| background is the color (in rgb or grey or palette index, as |
| appropriate). note that paletted files are taken care of elsewhere */ |
| void |
| png_do_background(png_row_info *row_info, png_byte *row, |
| png_color_16 *trans_values, png_color_16 *background, |
| png_color_16 *background_1, |
| png_byte *gamma_table, png_byte *gamma_from_1, png_byte *gamma_to_1, |
| png_uint_16 **gamma_16, png_uint_16 **gamma_16_from_1, |
| png_uint_16 **gamma_16_to_1, int gamma_shift) |
| { |
| if (row && row_info && background && |
| (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) || |
| (row_info->color_type != PNG_COLOR_TYPE_PALETTE && |
| trans_values))) |
| { |
| switch (row_info->color_type) |
| { |
| case PNG_COLOR_TYPE_GRAY: |
| { |
| switch (row_info->bit_depth) |
| { |
| case 1: |
| { |
| png_byte *sp; |
| int shift; |
| png_uint_32 i; |
| |
| sp = row; |
| shift = 7; |
| for (i = 0; i < row_info->width; i++) |
| { |
| if (((*sp >> shift) & 0x1) == |
| trans_values->gray) |
| { |
| *sp &= ((0x7f7f >> (7 - shift)) & 0xff); |
| *sp |= (background->gray << shift); |
| } |
| if (!shift) |
| { |
| shift = 7; |
| sp++; |
| } |
| else |
| shift--; |
| } |
| break; |
| } |
| case 2: |
| { |
| png_byte *sp; |
| int shift; |
| png_uint_32 i; |
| |
| sp = row; |
| shift = 6; |
| for (i = 0; i < row_info->width; i++) |
| { |
| if (((*sp >> shift) & 0x3) == |
| trans_values->gray) |
| { |
| *sp &= ((0x3f3f >> (6 - shift)) & 0xff); |
| *sp |= (background->gray << shift); |
| } |
| if (!shift) |
| { |
| shift = 6; |
| sp++; |
| } |
| else |
| shift -= 2; |
| } |
| break; |
| } |
| case 4: |
| { |
| png_byte *sp; |
| int shift; |
| png_uint_32 i; |
| |
| sp = row + 1; |
| shift = 4; |
| for (i = 0; i < row_info->width; i++) |
| { |
| if (((*sp >> shift) & 0xf) == |
| trans_values->gray) |
| { |
| *sp &= ((0xf0f >> (4 - shift)) & 0xff); |
| *sp |= (background->gray << shift); |
| } |
| if (!shift) |
| { |
| shift = 4; |
| sp++; |
| } |
| else |
| shift -= 4; |
| } |
| break; |
| } |
| case 8: |
| { |
| if (gamma_table) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++, sp++) |
| { |
| if (*sp == trans_values->gray) |
| { |
| *sp = background->gray; |
| } |
| else |
| { |
| *sp = gamma_table[*sp]; |
| } |
| } |
| } |
| else |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++, sp++) |
| { |
| if (*sp == trans_values->gray) |
| { |
| *sp = background->gray; |
| } |
| } |
| } |
| break; |
| } |
| case 16: |
| { |
| if (gamma_16) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++, sp += 2) |
| { |
| png_uint_16 v; |
| |
| v = ((png_uint_16)(*sp) << 8) + |
| (png_uint_16)(*(sp + 1)); |
| if (v == trans_values->gray) |
| { |
| *sp = (background->gray >> 8) & 0xff; |
| *(sp + 1) = background->gray & 0xff; |
| } |
| else |
| { |
| v = gamma_16[ |
| *(sp + 1) >> gamma_shift][*sp]; |
| *sp = (v >> 8) & 0xff; |
| *(sp + 1) = v & 0xff; |
| } |
| } |
| } |
| else |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++, sp += 2) |
| { |
| png_uint_16 v; |
| |
| v = ((png_uint_16)(*sp) << 8) + |
| (png_uint_16)(*(sp + 1)); |
| if (v == trans_values->gray) |
| { |
| *sp = (background->gray >> 8) & 0xff; |
| *(sp + 1) = background->gray & 0xff; |
| } |
| } |
| } |
| break; |
| } |
| } |
| break; |
| } |
| case PNG_COLOR_TYPE_RGB: |
| { |
| if (row_info->bit_depth == 8) |
| { |
| if (gamma_table) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++, sp += 3) |
| { |
| if (*sp == trans_values->red && |
| *(sp + 1) == trans_values->green && |
| *(sp + 2) == trans_values->blue) |
| { |
| *sp = background->red; |
| *(sp + 1) = background->green; |
| *(sp + 2) = background->blue; |
| } |
| else |
| { |
| *sp = gamma_table[*sp]; |
| *(sp + 1) = gamma_table[*(sp + 1)]; |
| *(sp + 2) = gamma_table[*(sp + 2)]; |
| } |
| } |
| } |
| else |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++, sp += 3) |
| { |
| if (*sp == trans_values->red && |
| *(sp + 1) == trans_values->green && |
| *(sp + 2) == trans_values->blue) |
| { |
| *sp = background->red; |
| *(sp + 1) = background->green; |
| *(sp + 2) = background->blue; |
| } |
| } |
| } |
| } |
| else if (row_info->bit_depth == 16) |
| { |
| if (gamma_16) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++, sp += 6) |
| { |
| png_uint_16 r, g, b; |
| |
| r = ((png_uint_16)(*sp) << 8) + |
| (png_uint_16)(*(sp + 1)); |
| g = ((png_uint_16)(*(sp + 2)) << 8) + |
| (png_uint_16)(*(sp + 3)); |
| b = ((png_uint_16)(*(sp + 4)) << 8) + |
| (png_uint_16)(*(sp + 5)); |
| if (r == trans_values->red && |
| g == trans_values->green && |
| b == trans_values->blue) |
| { |
| *sp = (background->red >> 8) & 0xff; |
| *(sp + 1) = background->red & 0xff; |
| *(sp + 2) = (background->green >> 8) & 0xff; |
| *(sp + 3) = background->green & 0xff; |
| *(sp + 4) = (background->blue >> 8) & 0xff; |
| *(sp + 5) = background->blue & 0xff; |
| } |
| else |
| { |
| png_uint_16 v; |
| v = gamma_16[ |
| *(sp + 1) >> gamma_shift][*sp]; |
| *sp = (v >> 8) & 0xff; |
| *(sp + 1) = v & 0xff; |
| v = gamma_16[ |
| *(sp + 3) >> gamma_shift][*(sp + 2)]; |
| *(sp + 2) = (v >> 8) & 0xff; |
| *(sp + 3) = v & 0xff; |
| v = gamma_16[ |
| *(sp + 5) >> gamma_shift][*(sp + 4)]; |
| *(sp + 4) = (v >> 8) & 0xff; |
| *(sp + 5) = v & 0xff; |
| } |
| } |
| } |
| else |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++, sp += 6) |
| { |
| png_uint_16 r, g, b; |
| |
| r = ((png_uint_16)(*sp) << 8) + |
| (png_uint_16)(*(sp + 1)); |
| g = ((png_uint_16)(*(sp + 2)) << 8) + |
| (png_uint_16)(*(sp + 3)); |
| b = ((png_uint_16)(*(sp + 4)) << 8) + |
| (png_uint_16)(*(sp + 5)); |
| if (r == trans_values->red && |
| g == trans_values->green && |
| b == trans_values->blue) |
| { |
| *sp = (background->red >> 8) & 0xff; |
| *(sp + 1) = background->red & 0xff; |
| *(sp + 2) = (background->green >> 8) & 0xff; |
| *(sp + 3) = background->green & 0xff; |
| *(sp + 4) = (background->blue >> 8) & 0xff; |
| *(sp + 5) = background->blue & 0xff; |
| } |
| } |
| } |
| } |
| break; |
| } |
| case PNG_COLOR_TYPE_GRAY_ALPHA: |
| { |
| switch (row_info->bit_depth) |
| { |
| case 8: |
| { |
| if (gamma_to_1 && gamma_from_1 && gamma_table) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row, |
| dp = row; |
| i < row_info->width; i++, sp += 2, dp++) |
| { |
| png_uint_16 a; |
| |
| a = *(sp + 1); |
| if (a == 0xff) |
| { |
| *dp = gamma_table[*sp]; |
| } |
| else if (a == 0) |
| { |
| *dp = background->gray; |
| } |
| else |
| { |
| png_uint_16 v; |
| |
| v = gamma_to_1[*sp]; |
| v = ((png_uint_16)(v) * a + |
| (png_uint_16)background_1->gray * |
| (255 - a) + 127) / 255; |
| *dp = gamma_from_1[v]; |
| } |
| } |
| } |
| else |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row, |
| dp = row; |
| i < row_info->width; i++, sp += 2, dp++) |
| { |
| png_uint_16 a; |
| |
| a = *(sp + 1); |
| if (a == 0xff) |
| { |
| *dp = *sp; |
| } |
| else if (a == 0) |
| { |
| *dp = background->gray; |
| } |
| else |
| { |
| *dp = ((png_uint_16)(*sp) * a + |
| (png_uint_16)background_1->gray * |
| (255 - a) + 127) / 255; |
| } |
| } |
| } |
| break; |
| } |
| case 16: |
| { |
| if (gamma_16 && gamma_16_from_1 && gamma_16_to_1) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row, |
| dp = row; |
| i < row_info->width; i++, sp += 4, dp += 2) |
| { |
| png_uint_16 a; |
| |
| a = ((png_uint_16)(*(sp + 2)) << 8) + |
| (png_uint_16)(*(sp + 3)); |
| if (a == (png_uint_16)0xffff) |
| { |
| png_uint_32 v; |
| |
| v = gamma_16[ |
| *(sp + 1) >> gamma_shift][*sp]; |
| *dp = (png_byte)((v >> 8) & 0xff); |
| *(dp + 1) = (png_byte)(v & 0xff); |
| } |
| else if (a == 0) |
| { |
| *dp = (background->gray >> 8) & 0xff; |
| *(dp + 1) = background->gray & 0xff; |
| } |
| else |
| { |
| png_uint_32 g, v; |
| |
| g = gamma_16_to_1[ |
| *(sp + 1) >> gamma_shift][*sp]; |
| v = (g * (png_uint_32)a + |
| (png_uint_32)background_1->gray * |
| (png_uint_32)((png_uint_16)65535 - a) + |
| (png_uint_16)32767) / (png_uint_16)65535; |
| v = gamma_16_from_1[(size_t)( |
| (v & 0xff) >> gamma_shift)][(size_t)(v >> 8)]; |
| *dp = (png_byte)((v >> 8) & 0xff); |
| *(dp + 1) = (png_byte)(v & 0xff); |
| } |
| } |
| } |
| else |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row, |
| dp = row; |
| i < row_info->width; i++, sp += 4, dp += 2) |
| { |
| png_uint_16 a; |
| |
| a = ((png_uint_16)(*(sp + 2)) << 8) + |
| (png_uint_16)(*(sp + 3)); |
| if (a == (png_uint_16)0xffff) |
| { |
| memcpy(dp, sp, 2); |
| } |
| else if (a == 0) |
| { |
| *dp = (background->gray >> 8) & 0xff; |
| *(dp + 1) = background->gray & 0xff; |
| } |
| else |
| { |
| png_uint_32 g, v; |
| |
| g = ((png_uint_32)(*sp) << 8) + |
| (png_uint_32)(*(sp + 1)); |
| v = (g * (png_uint_32)a + |
| (png_uint_32)background_1->gray * |
| (png_uint_32)((png_uint_16)65535 - a) + |
| (png_uint_16)32767) / (png_uint_16)65535; |
| *dp = (png_byte)((v >> 8) & 0xff); |
| *(dp + 1) = (png_byte)(v & 0xff); |
| } |
| } |
| } |
| break; |
| } |
| } |
| break; |
| } |
| case PNG_COLOR_TYPE_RGB_ALPHA: |
| { |
| if (row_info->bit_depth == 8) |
| { |
| if (gamma_to_1 && gamma_from_1 && gamma_table) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row, |
| dp = row; |
| i < row_info->width; i++, sp += 4, dp += 3) |
| { |
| png_uint_16 a; |
| |
| 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) |
| { |
| *dp = background->red; |
| *(dp + 1) = background->green; |
| *(dp + 2) = background->blue; |
| } |
| else |
| { |
| png_uint_16 v; |
| |
| v = gamma_to_1[*sp]; |
| v = ((png_uint_16)(v) * a + |
| (png_uint_16)background_1->red * |
| (255 - a) + 127) / 255; |
| *dp = gamma_from_1[v]; |
| v = gamma_to_1[*(sp + 1)]; |
| v = ((png_uint_16)(v) * a + |
| (png_uint_16)background_1->green * |
| (255 - a) + 127) / 255; |
| *(dp + 1) = gamma_from_1[v]; |
| v = gamma_to_1[*(sp + 2)]; |
| v = ((png_uint_16)(v) * a + |
| (png_uint_16)background_1->blue * |
| (255 - a) + 127) / 255; |
| *(dp + 2) = gamma_from_1[v]; |
| } |
| } |
| } |
| else |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row, |
| dp = row; |
| i < row_info->width; i++, sp += 4, dp += 3) |
| { |
| png_uint_16 a; |
| |
| a = *(sp + 3); |
| if (a == 0xff) |
| { |
| *dp = *sp; |
| *(dp + 1) = *(sp + 1); |
| *(dp + 2) = *(sp + 2); |
| } |
| else if (a == 0) |
| { |
| *dp = background->red; |
| *(dp + 1) = background->green; |
| *(dp + 2) = background->blue; |
| } |
| else |
| { |
| *dp = ((png_uint_16)(*sp) * a + |
| (png_uint_16)background->red * |
| (255 - a) + 127) / 255; |
| *(dp + 1) = ((png_uint_16)(*(sp + 1)) * a + |
| (png_uint_16)background->green * |
| (255 - a) + 127) / 255; |
| *(dp + 2) = ((png_uint_16)(*(sp + 2)) * a + |
| (png_uint_16)background->blue * |
| (255 - a) + 127) / 255; |
| } |
| } |
| } |
| } |
| else if (row_info->bit_depth == 16) |
| { |
| if (gamma_16 && gamma_16_from_1 && gamma_16_to_1) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row, |
| dp = row; |
| i < row_info->width; i++, sp += 8, dp += 6) |
| { |
| png_uint_16 a; |
| |
| a = ((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 = (v >> 8) & 0xff; |
| *(dp + 1) = v & 0xff; |
| v = gamma_16[ |
| *(sp + 3) >> gamma_shift][*(sp + 2)]; |
| *(dp + 2) = (v >> 8) & 0xff; |
| *(dp + 3) = v & 0xff; |
| v = gamma_16[ |
| *(sp + 5) >> gamma_shift][*(sp + 4)]; |
| *(dp + 4) = (v >> 8) & 0xff; |
| *(dp + 5) = v & 0xff; |
| } |
| else if (a == 0) |
| { |
| *dp = (background->red >> 8) & 0xff; |
| *(dp + 1) = background->red & 0xff; |
| *(dp + 2) = (background->green >> 8) & 0xff; |
| *(dp + 3) = background->green & 0xff; |
| *(dp + 4) = (background->blue >> 8) & 0xff; |
| *(dp + 5) = background->blue & 0xff; |
| } |
| else |
| { |
| png_uint_32 v; |
| |
| v = gamma_16_to_1[ |
| *(sp + 1) >> gamma_shift][*sp]; |
| v = (v * (png_uint_32)a + |
| (png_uint_32)background->red * |
| (png_uint_32)((png_uint_16)65535 - a) + |
| (png_uint_16)32767) / (png_uint_16)65535; |
| v = gamma_16_from_1[(size_t)( |
| (v & 0xff) >> gamma_shift)][(size_t)(v >> 8)]; |
| *dp = (png_byte)((v >> 8) & 0xff); |
| *(dp + 1) = (png_byte)(v & 0xff); |
| v = gamma_16_to_1[ |
| *(sp + 3) >> gamma_shift][*(sp + 2)]; |
| v = (v * (png_uint_32)a + |
| (png_uint_32)background->green * |
| (png_uint_32)((png_uint_16)65535 - a) + |
| (png_uint_16)32767) / (png_uint_16)65535; |
| v = gamma_16_from_1[(size_t)( |
| (v & 0xff) >> gamma_shift)][(size_t)(v >> 8)]; |
| *(dp + 2) = (png_byte)((v >> 8) & 0xff); |
| *(dp + 3) = (png_byte)(v & 0xff); |
| v = gamma_16_to_1[ |
| *(sp + 5) >> gamma_shift][*(sp + 4)]; |
| v = (v * (png_uint_32)a + |
| (png_uint_32)background->blue * |
| (png_uint_32)((png_uint_16)65535 - a) + |
| (png_uint_16)32767) / (png_uint_16)65535; |
| v = gamma_16_from_1[(size_t)( |
| (v & 0xff) >> gamma_shift)][(size_t)(v >> 8)]; |
| *(dp + 4) = (png_byte)((v >> 8) & 0xff); |
| *(dp + 5) = (png_byte)(v & 0xff); |
| } |
| } |
| } |
| else |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row, |
| dp = row; |
| i < row_info->width; i++, sp += 8, dp += 6) |
| { |
| png_uint_16 a; |
| |
| a = ((png_uint_16)(*(sp + 6)) << 8) + |
| (png_uint_16)(*(sp + 7)); |
| if (a == (png_uint_16)0xffff) |
| { |
| memcpy(dp, sp, 6); |
| } |
| else if (a == 0) |
| { |
| *dp = (background->red >> 8) & 0xff; |
| *(dp + 1) = background->red & 0xff; |
| *(dp + 2) = (background->green >> 8) & 0xff; |
| *(dp + 3) = background->green & 0xff; |
| *(dp + 4) = (background->blue >> 8) & 0xff; |
| *(dp + 5) = background->blue & 0xff; |
| } |
| else |
| { |
| png_uint_32 r, g, b, v; |
| |
| r = ((png_uint_32)(*sp) << 8) + |
| (png_uint_32)(*(sp + 1)); |
| g = ((png_uint_32)(*(sp + 2)) << 8) + |
| (png_uint_32)(*(sp + 3)); |
| b = ((png_uint_32)(*(sp + 4)) << 8) + |
| (png_uint_32)(*(sp + 5)); |
| v = (r * (png_uint_32)a + |
| (png_uint_32)background->red * |
| (png_uint_32)((png_uint_32)65535 - a) + |
| (png_uint_32)32767) / (png_uint_32)65535; |
| *dp = (png_byte)((v >> 8) & 0xff); |
| *(dp + 1) = (png_byte)(v & 0xff); |
| v = (g * (png_uint_32)a + |
| (png_uint_32)background->green * |
| (png_uint_32)((png_uint_32)65535 - a) + |
| (png_uint_32)32767) / (png_uint_32)65535; |
| *(dp + 2) = (png_byte)((v >> 8) & 0xff); |
| *(dp + 3) = (png_byte)(v & 0xff); |
| v = (b * (png_uint_32)a + |
| (png_uint_32)background->blue * |
| (png_uint_32)((png_uint_32)65535 - a) + |
| (png_uint_32)32767) / (png_uint_32)65535; |
| *(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 -= 1; |
| row_info->pixel_depth = row_info->channels * |
| row_info->bit_depth; |
| row_info->rowbytes = ((row_info->width * |
| row_info->pixel_depth + 7) >> 3); |
| } |
| } |
| } |
| |
| /* gamma correct the image, avoiding the alpha channel. Make sure |
| you do this after you deal with the trasparency 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(). If your bit depth < 8, gamma correct a |
| palette, not the data. */ |
| void |
| png_do_gamma(png_row_info *row_info, png_byte *row, |
| png_byte *gamma_table, png_uint_16 **gamma_16_table, |
| int gamma_shift) |
| { |
| if (row && row_info && ((row_info->bit_depth <= 8 && gamma_table) || |
| (row_info->bit_depth == 16 && gamma_16_table))) |
| { |
| switch (row_info->color_type) |
| { |
| case PNG_COLOR_TYPE_RGB: |
| { |
| if (row_info->bit_depth == 8) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++) |
| { |
| *sp = gamma_table[*sp]; |
| sp++; |
| *sp = gamma_table[*sp]; |
| sp++; |
| *sp = gamma_table[*sp]; |
| sp++; |
| } |
| } |
| else if (row_info->bit_depth == 16) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++) |
| { |
| png_uint_16 v; |
| |
| v = gamma_16_table[*(sp + 1) >> |
| gamma_shift][*sp]; |
| *sp = (v >> 8) & 0xff; |
| *(sp + 1) = v & 0xff; |
| sp += 2; |
| v = gamma_16_table[*(sp + 1) >> |
| gamma_shift][*sp]; |
| *sp = (v >> 8) & 0xff; |
| *(sp + 1) = v & 0xff; |
| sp += 2; |
| v = gamma_16_table[*(sp + 1) >> |
| gamma_shift][*sp]; |
| *sp = (v >> 8) & 0xff; |
| *(sp + 1) = v & 0xff; |
| sp += 2; |
| } |
| } |
| break; |
| } |
| case PNG_COLOR_TYPE_RGB_ALPHA: |
| { |
| if (row_info->bit_depth == 8) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->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) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++) |
| { |
| png_uint_16 v; |
| |
| v = gamma_16_table[*(sp + 1) >> |
| gamma_shift][*sp]; |
| *sp = (v >> 8) & 0xff; |
| *(sp + 1) = v & 0xff; |
| sp += 2; |
| v = gamma_16_table[*(sp + 1) >> |
| gamma_shift][*sp]; |
| *sp = (v >> 8) & 0xff; |
| *(sp + 1) = v & 0xff; |
| sp += 2; |
| v = gamma_16_table[*(sp + 1) >> |
| gamma_shift][*sp]; |
| *sp = (v >> 8) & 0xff; |
| *(sp + 1) = v & 0xff; |
| sp += 4; |
| } |
| } |
| break; |
| } |
| case PNG_COLOR_TYPE_GRAY_ALPHA: |
| { |
| if (row_info->bit_depth == 8) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++) |
| { |
| *sp = gamma_table[*sp]; |
| sp++; |
| sp++; |
| } |
| } |
| else if (row_info->bit_depth == 16) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++) |
| { |
| png_uint_16 v; |
| |
| v = gamma_16_table[*(sp + 1) >> |
| gamma_shift][*sp]; |
| *sp = (v >> 8) & 0xff; |
| *(sp + 1) = v & 0xff; |
| sp += 4; |
| } |
| } |
| break; |
| } |
| case PNG_COLOR_TYPE_GRAY: |
| { |
| if (row_info->bit_depth == 8) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++) |
| { |
| *sp = gamma_table[*sp]; |
| sp++; |
| } |
| } |
| else if (row_info->bit_depth == 16) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| for (i = 0, sp = row; |
| i < row_info->width; i++) |
| { |
| png_uint_16 v; |
| |
| v = gamma_16_table[*(sp + 1) >> |
| gamma_shift][*sp]; |
| *sp = (v >> 8) & 0xff; |
| *(sp + 1) = v & 0xff; |
| sp += 2; |
| } |
| } |
| break; |
| } |
| } |
| } |
| } |
| |
| /* expands a palette row to an rgb or rgba row depending |
| upon whether you supply trans and num_trans */ |
| void |
| png_do_expand_palette(png_row_info *row_info, png_byte *row, |
| png_color *palette, |
| png_byte *trans, int num_trans) |
| { |
| if (row && row_info && row_info->color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| if (row_info->bit_depth < 8) |
| { |
| switch (row_info->bit_depth) |
| { |
| case 1: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)((row_info->width - 1) >> 3); |
| dp = row + (png_size_t)row_info->width - 1; |
| shift = 7 - (int)((row_info->width + 7) & 7); |
| for (i = 0; i < row_info->width; i++) |
| { |
| if ((*sp >> shift) & 0x1) |
| *dp = 1; |
| else |
| *dp = 0; |
| if (shift == 7) |
| { |
| shift = 0; |
| sp--; |
| } |
| else |
| shift++; |
| |
| dp--; |
| } |
| break; |
| } |
| case 2: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift, value; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)((row_info->width - 1) >> 2); |
| dp = row + (png_size_t)row_info->width - 1; |
| shift = (int)((3 - ((row_info->width + 3) & 3)) << 1); |
| for (i = 0; i < row_info->width; i++) |
| { |
| value = (*sp >> shift) & 0x3; |
| *dp = value; |
| if (shift == 6) |
| { |
| shift = 0; |
| sp--; |
| } |
| else |
| shift += 2; |
| |
| dp--; |
| } |
| break; |
| } |
| case 4: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift, value; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)((row_info->width - 1) >> 1); |
| dp = row + (png_size_t)row_info->width - 1; |
| shift = (int)((row_info->width & 1) << 2); |
| for (i = 0; i < row_info->width; i++) |
| { |
| value = (*sp >> shift) & 0xf; |
| *dp = 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_info->width; |
| } |
| switch (row_info->bit_depth) |
| { |
| case 8: |
| { |
| if (trans) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)row_info->width - 1; |
| dp = row + (png_size_t)(row_info->width << 2) - 1; |
| |
| for (i = 0; i < row_info->width; i++) |
| { |
| if (*sp >= (png_byte)num_trans) |
| *dp-- = 0xff; |
| else |
| *dp-- = trans[*sp]; |
| *dp-- = palette[*sp].blue; |
| *dp-- = palette[*sp].green; |
| *dp-- = palette[*sp].red; |
| sp--; |
| } |
| row_info->bit_depth = 8; |
| row_info->pixel_depth = 32; |
| row_info->rowbytes = row_info->width * 4; |
| row_info->color_type = 6; |
| row_info->channels = 4; |
| } |
| else |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)row_info->width - 1; |
| dp = row + (png_size_t)(row_info->width * 3) - 1; |
| |
| for (i = 0; i < row_info->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_info->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 |
| transparency value is supplied, an alpha channel is built. */ |
| void |
| png_do_expand(png_row_info *row_info, png_byte *row, |
| png_color_16 *trans_value) |
| { |
| if (row && row_info) |
| { |
| if (row_info->color_type == PNG_COLOR_TYPE_GRAY && |
| row_info->bit_depth < 8) |
| { |
| switch (row_info->bit_depth) |
| { |
| case 1: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)((row_info->width - 1) >> 3); |
| dp = row + (png_size_t)row_info->width - 1; |
| shift = 7 - (int)((row_info->width + 7) & 7); |
| for (i = 0; i < row_info->width; i++) |
| { |
| if ((*sp >> shift) & 0x1) |
| *dp = 0xff; |
| else |
| *dp = 0; |
| if (shift == 7) |
| { |
| shift = 0; |
| sp--; |
| } |
| else |
| shift++; |
| |
| dp--; |
| } |
| break; |
| } |
| case 2: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift, value; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)((row_info->width - 1) >> 2); |
| dp = row + (png_size_t)row_info->width - 1; |
| shift = (int)((3 - ((row_info->width + 3) & 3)) << 1); |
| for (i = 0; i < row_info->width; i++) |
| { |
| value = (*sp >> shift) & 0x3; |
| *dp = (value | (value << 2) | (value << 4) | |
| (value << 6)); |
| if (shift == 6) |
| { |
| shift = 0; |
| sp--; |
| } |
| else |
| shift += 2; |
| |
| dp--; |
| } |
| break; |
| } |
| case 4: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift, value; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)((row_info->width - 1) >> 1); |
| dp = row + (png_size_t)row_info->width - 1; |
| shift = (int)((1 - ((row_info->width + 1) & 1)) << 2); |
| for (i = 0; i < row_info->width; i++) |
| { |
| value = (*sp >> shift) & 0xf; |
| *dp = (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_info->width; |
| } |
| if (row_info->color_type == PNG_COLOR_TYPE_GRAY && trans_value) |
| { |
| if (row_info->bit_depth == 8) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)row_info->width - 1; |
| dp = row + (png_size_t)(row_info->width << 1) - 1; |
| for (i = 0; i < row_info->width; i++) |
| { |
| if (*sp == trans_value->gray) |
| *dp-- = 0; |
| else |
| *dp-- = 0xff; |
| *dp-- = *sp--; |
| } |
| } |
| else if (row_info->bit_depth == 16) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)row_info->rowbytes - 1; |
| dp = row + (png_size_t)(row_info->rowbytes << 1) - 1; |
| for (i = 0; i < row_info->width; i++) |
| { |
| if (((png_uint_16)*(sp) | |
| ((png_uint_16)*(sp - 1) << 8)) == trans_value->gray) |
| { |
| *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 = (row_info->bit_depth << 1); |
| row_info->rowbytes = |
| ((row_info->width * row_info->pixel_depth) >> 3); |
| } |
| else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value) |
| { |
| if (row_info->bit_depth == 8) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)row_info->rowbytes - 1; |
| dp = row + (png_size_t)(row_info->width << 2) - 1; |
| for (i = 0; i < row_info->width; i++) |
| { |
| if (*(sp - 2) == trans_value->red && |
| *(sp - 1) == trans_value->green && |
| *(sp - 0) == trans_value->blue) |
| *dp-- = 0; |
| else |
| *dp-- = 0xff; |
| *dp-- = *sp--; |
| *dp-- = *sp--; |
| *dp-- = *sp--; |
| } |
| } |
| else if (row_info->bit_depth == 16) |
| { |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| sp = row + (png_size_t)row_info->rowbytes - 1; |
| dp = row + (png_size_t)(row_info->width << 3) - 1; |
| for (i = 0; i < row_info->width; i++) |
| { |
| if ((((png_uint_16)*(sp - 4) | |
| ((png_uint_16)*(sp - 5) << 8)) == trans_value->red) && |
| (((png_uint_16)*(sp - 2) | |
| ((png_uint_16)*(sp - 3) << 8)) == trans_value->green) && |
| (((png_uint_16)*(sp - 0) | |
| ((png_uint_16)*(sp - 1) << 8)) == trans_value->blue)) |
| { |
| *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 = (row_info->bit_depth << 2); |
| row_info->rowbytes = |
| ((row_info->width * row_info->pixel_depth) >> 3); |
| } |
| } |
| } |
| |
| void |
| png_do_dither(png_row_info *row_info, png_byte *row, |
| png_byte *palette_lookup, png_byte *dither_lookup) |
| { |
| if (row && row_info) |
| { |
| if (row_info->color_type == PNG_COLOR_TYPE_RGB && |
| palette_lookup && row_info->bit_depth == 8) |
| { |
| int r, g, b, p; |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| sp = row; |
| dp = row; |
| for (i = 0; i < row_info->width; i++) |
| { |
| r = *sp++; |
| g = *sp++; |
| b = *sp++; |
| |
| /* this looks real messy, but the compiler will reduce |
| it down to a reasonable formula. For example, with |
| 5 bits per color, we get: |
| p = (((r >> 3) & 0x1f) << 10) | |
| (((g >> 3) & 0x1f) << 5) | |
| ((b >> 3) & 0x1f); |
| */ |
| p = (((r >> (8 - PNG_DITHER_RED_BITS)) & |
| ((1 << PNG_DITHER_RED_BITS) - 1)) << |
| (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) | |
| (((g >> (8 - PNG_DITHER_GREEN_BITS)) & |
| ((1 << PNG_DITHER_GREEN_BITS) - 1)) << |
| (PNG_DITHER_BLUE_BITS)) | |
| ((b >> (8 - PNG_DITHER_BLUE_BITS)) & |
| ((1 << PNG_DITHER_BLUE_BITS) - 1)); |
| |
| *dp++ = palette_lookup[p]; |
| } |
| row_info->color_type = PNG_COLOR_TYPE_PALETTE; |
| row_info->channels = 1; |
| row_info->pixel_depth = row_info->bit_depth; |
| row_info->rowbytes = |
| ((row_info->width * row_info->pixel_depth + 7) >> 3); |
| } |
| else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA && |
| palette_lookup && row_info->bit_depth == 8) |
| { |
| int r, g, b, p; |
| png_byte *sp, *dp; |
| png_uint_32 i; |
| |
| sp = row; |
| dp = row; |
| for (i = 0; i < row_info->width; i++) |
| { |
| r = *sp++; |
| g = *sp++; |
| b = *sp++; |
| sp++; |
| |
| p = (((r >> (8 - PNG_DITHER_RED_BITS)) & |
| ((1 << PNG_DITHER_RED_BITS) - 1)) << |
| (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) | |
| (((g >> (8 - PNG_DITHER_GREEN_BITS)) & |
| ((1 << PNG_DITHER_GREEN_BITS) - 1)) << |
| (PNG_DITHER_BLUE_BITS)) | |
| ((b >> (8 - PNG_DITHER_BLUE_BITS)) & |
| ((1 << PNG_DITHER_BLUE_BITS) - 1)); |
| |
| *dp++ = palette_lookup[p]; |
| } |
| row_info->color_type = PNG_COLOR_TYPE_PALETTE; |
| row_info->channels = 1; |
| row_info->pixel_depth = row_info->bit_depth; |
| row_info->rowbytes = |
| ((row_info->width * row_info->pixel_depth + 7) >> 3); |
| } |
| else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE && |
| dither_lookup && row_info->bit_depth == 8) |
| { |
| png_byte *sp; |
| png_uint_32 i; |
| |
| sp = row; |
| for (i = 0; i < row_info->width; i++, sp++) |
| { |
| *sp = dither_lookup[*sp]; |
| } |
| } |
| } |
| } |
| |
| static int png_gamma_shift[] = |
| {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0}; |
| |
| void |
| png_build_gamma_table(png_struct *png_ptr) |
| { |
| if (png_ptr->bit_depth <= 8) |
| { |
| int i; |
| double g; |
| |
| g = 1.0 / (png_ptr->gamma * png_ptr->display_gamma); |
| |
| png_ptr->gamma_table = (png_byte *)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 (png_ptr->transformations & PNG_BACKGROUND) |
| { |
| g = 1.0 / (png_ptr->gamma); |
| |
| png_ptr->gamma_to_1 = (png_byte *)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); |
| } |
| |
| g = 1.0 / (png_ptr->display_gamma); |
| |
| png_ptr->gamma_from_1 = (png_byte *)png_malloc(png_ptr, |
| (png_uint_32)256); |
| |
| for (i = 0; i < 256; i++) |
| { |
| png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0, |
| g) * 255.0 + .5); |
| } |
| } |
| } |
| 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 = shift; |
| |
| num = (1 << (8 - shift)); |
| |
| g = 1.0 / (png_ptr->gamma * png_ptr->display_gamma); |
| |
| png_ptr->gamma_16_table = (png_uint_16 **)png_malloc(png_ptr, |
| num * sizeof (png_uint_16 *)); |
| |
| if ((png_ptr->transformations & PNG_16_TO_8) && |
| !(png_ptr->transformations & PNG_BACKGROUND)) |
| { |
| double fin, fout; |
| png_uint_32 last, max; |
| |
| for (i = 0; i < num; i++) |
| { |
| png_ptr->gamma_16_table[i] = (png_uint_16 *)png_malloc(png_ptr, |
| 256 * 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)(num << 8)); |
| while (last <= max) |
| { |
| png_ptr->gamma_16_table[(int)(last >> 8)] |
| [(int)(last & 0xff)] = |
| (png_uint_16)i | ((png_uint_16)i << 8); |
| last++; |
| } |
| } |
| while (last < (num << 8)) |
| { |
| png_ptr->gamma_16_table[(int)(last >> 8)][(int)(last & 0xff)] = |
| (png_uint_16)65535; |
| last++; |
| } |
| } |
| else |
| { |
| for (i = 0; i < num; i++) |
| { |
| png_ptr->gamma_16_table[i] = (png_uint_16 *)png_malloc(png_ptr, |
| 256 * 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 (png_ptr->transformations & PNG_BACKGROUND) |
| { |
| g = 1.0 / (png_ptr->gamma); |
| |
| png_ptr->gamma_16_to_1 = (png_uint_16 **)png_malloc(png_ptr, |
| num * sizeof (png_uint_16 *)); |
| |
| for (i = 0; i < num; i++) |
| { |
| png_ptr->gamma_16_to_1[i] = (png_uint_16 *)png_malloc(png_ptr, |
| 256 * 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); |
| } |
| } |
| g = 1.0 / (png_ptr->display_gamma); |
| |
| png_ptr->gamma_16_from_1 = (png_uint_16 **)png_malloc(png_ptr, |
| num * sizeof (png_uint_16 *)); |
| |
| for (i = 0; i < num; i++) |
| { |
| png_ptr->gamma_16_from_1[i] = (png_uint_16 *)png_malloc(png_ptr, |
| 256 * 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); |
| } |
| } |
| } |
| } |
| } |
