diff options
Diffstat (limited to 'src/3rdparty/libpng/pngrtran.c')
| -rw-r--r-- | src/3rdparty/libpng/pngrtran.c | 3020 |
1 files changed, 1889 insertions, 1131 deletions
diff --git a/src/3rdparty/libpng/pngrtran.c b/src/3rdparty/libpng/pngrtran.c index 30aa5dc..4e0401a 100644 --- a/src/3rdparty/libpng/pngrtran.c +++ b/src/3rdparty/libpng/pngrtran.c @@ -1,8 +1,8 @@ /* pngrtran.c - transforms the data in a row for PNG readers * - * Last changed in libpng 1.4.0 [January 3, 2010] - * Copyright (c) 1998-2010 Glenn Randers-Pehrson + * Last changed in libpng 1.5.4 [July 7, 2011] + * Copyright (c) 1998-2011 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.) * @@ -16,17 +16,16 @@ * in pngtrans.c. */ -#define PNG_NO_PEDANTIC_WARNINGS -#include "png.h" -#ifdef PNG_READ_SUPPORTED #include "pngpriv.h" +#ifdef PNG_READ_SUPPORTED + /* Set the action on getting a CRC error for an ancillary or critical chunk. */ void PNGAPI png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action) { png_debug(1, "in png_set_crc_action"); - + if (png_ptr == NULL) return; @@ -89,35 +88,69 @@ png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action) } } -#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ - defined(PNG_FLOATING_POINT_SUPPORTED) +#ifdef PNG_READ_BACKGROUND_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) +void PNGFAPI +png_set_background_fixed(png_structp png_ptr, + png_const_color_16p background_color, int background_gamma_code, + int need_expand, png_fixed_point background_gamma) { - png_debug(1, "in png_set_background"); - + png_debug(1, "in png_set_background_fixed"); + 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_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA; + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + png_memcpy(&(png_ptr->background), background_color, png_sizeof(png_color_16)); - png_ptr->background_gamma = (float)background_gamma; + png_ptr->background_gamma = background_gamma; png_ptr->background_gamma_type = (png_byte)(background_gamma_code); - png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0); + if (need_expand) + png_ptr->transformations |= PNG_BACKGROUND_EXPAND; + else + png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND; +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_background(png_structp png_ptr, + png_const_color_16p background_color, int background_gamma_code, + int need_expand, double background_gamma) +{ + png_set_background_fixed(png_ptr, background_color, background_gamma_code, + need_expand, png_fixed(png_ptr, background_gamma, "png_set_background")); +} +# endif /* FLOATING_POINT */ +#endif /* READ_BACKGROUND */ + +/* Scale 16-bit depth files to 8-bit depth. If both of these are set then the + * one that pngrtran does first (scale) happens. This is necessary to allow the + * TRANSFORM and API behavior to be somewhat consistent, and it's simpler. + */ +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED +void PNGAPI +png_set_scale_16(png_structp png_ptr) +{ + png_debug(1, "in png_set_scale_16"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= PNG_SCALE_16_TO_8; } #endif -#ifdef PNG_READ_16_TO_8_SUPPORTED -/* Strip 16 bit depth files to 8 bit depth */ +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED +/* Chop 16-bit depth files to 8-bit depth */ void PNGAPI png_set_strip_16(png_structp png_ptr) { @@ -125,6 +158,7 @@ png_set_strip_16(png_structp png_ptr) if (png_ptr == NULL) return; + png_ptr->transformations |= PNG_16_TO_8; } #endif @@ -137,17 +171,200 @@ png_set_strip_alpha(png_structp png_ptr) if (png_ptr == NULL) return; - png_ptr->flags |= PNG_FLAG_STRIP_ALPHA; + + png_ptr->transformations |= PNG_STRIP_ALPHA; } #endif -#ifdef PNG_READ_DITHER_SUPPORTED -/* Dither file to 8 bit. Supply a palette, the current number +#if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED) +static png_fixed_point +translate_gamma_flags(png_structp png_ptr, png_fixed_point output_gamma, + int is_screen) +{ + /* Check for flag values. The main reason for having the old Mac value as a + * flag is that it is pretty near impossible to work out what the correct + * value is from Apple documentation - a working Mac system is needed to + * discover the value! + */ + if (output_gamma == PNG_DEFAULT_sRGB || + output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB) + { + /* If there is no sRGB support this just sets the gamma to the standard + * sRGB value. (This is a side effect of using this function!) + */ +# ifdef PNG_READ_sRGB_SUPPORTED + png_ptr->flags |= PNG_FLAG_ASSUME_sRGB; +# endif + if (is_screen) + output_gamma = PNG_GAMMA_sRGB; + else + output_gamma = PNG_GAMMA_sRGB_INVERSE; + } + + else if (output_gamma == PNG_GAMMA_MAC_18 || + output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18) + { + if (is_screen) + output_gamma = PNG_GAMMA_MAC_OLD; + else + output_gamma = PNG_GAMMA_MAC_INVERSE; + } + + return output_gamma; +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +static png_fixed_point +convert_gamma_value(png_structp png_ptr, double output_gamma) +{ + /* The following silently ignores cases where fixed point (times 100,000) + * gamma values are passed to the floating point API. This is safe and it + * means the fixed point constants work just fine with the floating point + * API. The alternative would just lead to undetected errors and spurious + * bug reports. Negative values fail inside the _fixed API unless they + * correspond to the flag values. + */ + if (output_gamma > 0 && output_gamma < 128) + output_gamma *= PNG_FP_1; + + /* This preserves -1 and -2 exactly: */ + output_gamma = floor(output_gamma + .5); + + if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN) + png_fixed_error(png_ptr, "gamma value"); + + return (png_fixed_point)output_gamma; +} +# endif +#endif /* READ_ALPHA_MODE || READ_GAMMA */ + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED +void PNGFAPI +png_set_alpha_mode_fixed(png_structp png_ptr, int mode, + png_fixed_point output_gamma) +{ + int compose = 0; + png_fixed_point file_gamma; + + png_debug(1, "in png_set_alpha_mode"); + + if (png_ptr == NULL) + return; + + output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/); + + /* Validate the value to ensure it is in a reasonable range. The value + * is expected to be 1 or greater, but this range test allows for some + * viewing correction values. The intent is to weed out users of this API + * who use the inverse of the gamma value accidentally! Since some of these + * values are reasonable this may have to be changed. + */ + if (output_gamma < 70000 || output_gamma > 300000) + png_error(png_ptr, "output gamma out of expected range"); + + /* The default file gamma is the inverse of the output gamma; the output + * gamma may be changed below so get the file value first: + */ + file_gamma = png_reciprocal(output_gamma); + + /* There are really 8 possibilities here, composed of any combination + * of: + * + * premultiply the color channels + * do not encode non-opaque pixels + * encode the alpha as well as the color channels + * + * The differences disappear if the input/output ('screen') gamma is 1.0, + * because then the encoding is a no-op and there is only the choice of + * premultiplying the color channels or not. + * + * png_set_alpha_mode and png_set_background interact because both use + * png_compose to do the work. Calling both is only useful when + * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along + * with a default gamma value. Otherwise PNG_COMPOSE must not be set. + */ + switch (mode) + { + case PNG_ALPHA_PNG: /* default: png standard */ + /* No compose, but it may be set by png_set_background! */ + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + break; + + case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */ + compose = 1; + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + /* The output is linear: */ + output_gamma = PNG_FP_1; + break; + + case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */ + compose = 1; + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA; + /* output_gamma records the encoding of opaque pixels! */ + break; + + case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */ + compose = 1; + png_ptr->transformations |= PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + break; + + default: + png_error(png_ptr, "invalid alpha mode"); + } + + /* Only set the default gamma if the file gamma has not been set (this has + * the side effect that the gamma in a second call to png_set_alpha_mode will + * be ignored.) + */ + if (png_ptr->gamma == 0) + png_ptr->gamma = file_gamma; + + /* But always set the output gamma: */ + png_ptr->screen_gamma = output_gamma; + + /* Finally, if pre-multiplying, set the background fields to achieve the + * desired result. + */ + if (compose) + { + /* And obtain alpha pre-multiplication by composing on black: */ + png_memset(&png_ptr->background, 0, sizeof png_ptr->background); + png_ptr->background_gamma = png_ptr->gamma; /* just in case */ + png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE; + png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND; + + if (png_ptr->transformations & PNG_COMPOSE) + png_error(png_ptr, + "conflicting calls to set alpha mode and background"); + + png_ptr->transformations |= PNG_COMPOSE; + } + + /* New API, make sure apps call the correct initializers: */ + png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED; +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_alpha_mode(png_structp png_ptr, int mode, double output_gamma) +{ + png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr, + output_gamma)); +} +# endif +#endif + +#ifdef PNG_READ_QUANTIZE_SUPPORTED +/* Dither file to 8-bit. Supply a palette, the current number * of elements in the palette, the maximum number of elements * allowed, and a histogram if possible. If the current number * of colors is greater then the maximum number, the palette will be - * modified to fit in the maximum number. "full_dither" indicates - * whether we need a dithering cube set up for RGB images, or if we + * modified to fit in the maximum number. "full_quantize" indicates + * whether we need a quantizing cube set up for RGB images, or if we * simply are reducing the number of colors in a paletted image. */ @@ -161,24 +378,25 @@ typedef png_dsort FAR * png_dsortp; typedef png_dsort FAR * FAR * png_dsortpp; void PNGAPI -png_set_dither(png_structp png_ptr, png_colorp palette, - int num_palette, int maximum_colors, png_uint_16p histogram, - int full_dither) +png_set_quantize(png_structp png_ptr, png_colorp palette, + int num_palette, int maximum_colors, png_const_uint_16p histogram, + int full_quantize) { - png_debug(1, "in png_set_dither"); + png_debug(1, "in png_set_quantize"); if (png_ptr == NULL) return; - png_ptr->transformations |= PNG_DITHER; - if (!full_dither) + png_ptr->transformations |= PNG_QUANTIZE; + + if (!full_quantize) { int i; - png_ptr->dither_index = (png_bytep)png_malloc(png_ptr, - (png_uint_32)(num_palette * png_sizeof(png_byte))); + 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->dither_index[i] = (png_byte)i; + png_ptr->quantize_index[i] = (png_byte)i; } if (num_palette > maximum_colors) @@ -192,12 +410,12 @@ png_set_dither(png_structp png_ptr, png_colorp palette, int i; /* Initialize an array to sort colors */ - png_ptr->dither_sort = (png_bytep)png_malloc(png_ptr, - (png_uint_32)(num_palette * png_sizeof(png_byte))); + png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr, + (png_uint_32)(num_palette * png_sizeof(png_byte))); - /* Initialize the dither_sort array */ + /* Initialize the quantize_sort array */ for (i = 0; i < num_palette; i++) - png_ptr->dither_sort[i] = (png_byte)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 @@ -214,23 +432,24 @@ png_set_dither(png_structp png_ptr, png_colorp palette, done = 1; for (j = 0; j < i; j++) { - if (histogram[png_ptr->dither_sort[j]] - < histogram[png_ptr->dither_sort[j + 1]]) + if (histogram[png_ptr->quantize_sort[j]] + < histogram[png_ptr->quantize_sort[j + 1]]) { png_byte t; - t = png_ptr->dither_sort[j]; - png_ptr->dither_sort[j] = png_ptr->dither_sort[j + 1]; - png_ptr->dither_sort[j + 1] = t; + 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_dither) + if (full_quantize) { int j = num_palette; @@ -239,11 +458,12 @@ png_set_dither(png_structp png_ptr, png_colorp palette, */ for (i = 0; i < maximum_colors; i++) { - if ((int)png_ptr->dither_sort[i] >= maximum_colors) + if ((int)png_ptr->quantize_sort[i] >= maximum_colors) { do j--; - while ((int)png_ptr->dither_sort[j] >= maximum_colors); + while ((int)png_ptr->quantize_sort[j] >= maximum_colors); + palette[i] = palette[j]; } } @@ -258,32 +478,32 @@ png_set_dither(png_structp png_ptr, png_colorp palette, for (i = 0; i < maximum_colors; i++) { /* Only move the colors we need to */ - if ((int)png_ptr->dither_sort[i] >= maximum_colors) + if ((int)png_ptr->quantize_sort[i] >= maximum_colors) { png_color tmp_color; do j--; - while ((int)png_ptr->dither_sort[j] >= maximum_colors); + 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->dither_index[j] = (png_byte)i; - png_ptr->dither_index[i] = (png_byte)j; + 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->dither_index[i] >= maximum_colors) + 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->dither_index[i]; + 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++) { @@ -298,12 +518,12 @@ png_set_dither(png_structp png_ptr, png_colorp palette, } } /* Point to closest color */ - png_ptr->dither_index[i] = (png_byte)min_k; + png_ptr->quantize_index[i] = (png_byte)min_k; } } } - png_free(png_ptr, png_ptr->dither_sort); - png_ptr->dither_sort = NULL; + png_free(png_ptr, png_ptr->quantize_sort); + png_ptr->quantize_sort = NULL; } else { @@ -325,9 +545,9 @@ png_set_dither(png_structp png_ptr, png_colorp palette, /* 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_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))); + (png_uint_32)(num_palette * png_sizeof(png_byte))); /* Initialize the sort array */ for (i = 0; i < num_palette; i++) @@ -337,7 +557,7 @@ png_set_dither(png_structp png_ptr, png_colorp palette, } hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 * - png_sizeof(png_dsortp))); + png_sizeof(png_dsortp))); num_new_palette = num_palette; @@ -368,8 +588,10 @@ png_set_dither(png_structp png_ptr, png_colorp palette, 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; @@ -390,9 +612,9 @@ png_set_dither(png_structp png_ptr, png_colorp palette, 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) + < num_new_palette && + (int)png_ptr->index_to_palette[p->right] + < num_new_palette) { int j, next_j; @@ -409,31 +631,36 @@ png_set_dither(png_structp png_ptr, png_colorp palette, num_new_palette--; palette[png_ptr->index_to_palette[j]] - = palette[num_new_palette]; - if (!full_dither) + = palette[num_new_palette]; + if (!full_quantize) { int k; for (k = 0; k < num_palette; k++) { - if (png_ptr->dither_index[k] == - png_ptr->index_to_palette[j]) - png_ptr->dither_index[k] = - png_ptr->index_to_palette[next_j]; - if ((int)png_ptr->dither_index[k] == - num_new_palette) - png_ptr->dither_index[k] = - png_ptr->index_to_palette[j]; + 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]; + [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->palette_to_index[num_new_palette]; + + png_ptr->index_to_palette[j] = + (png_byte)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; + png_ptr->palette_to_index[num_new_palette] = + (png_byte)j; } if (num_new_palette <= maximum_colors) break; @@ -473,36 +700,38 @@ png_set_dither(png_structp png_ptr, png_colorp palette, } png_ptr->num_palette = (png_uint_16)num_palette; - if (full_dither) + if (full_quantize) { int i; png_bytep distance; - int total_bits = PNG_DITHER_RED_BITS + PNG_DITHER_GREEN_BITS + - PNG_DITHER_BLUE_BITS; - int num_red = (1 << PNG_DITHER_RED_BITS); - int num_green = (1 << PNG_DITHER_GREEN_BITS); - int num_blue = (1 << PNG_DITHER_BLUE_BITS); + 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))); + 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_sizeof(png_byte))); + png_memset(distance, 0xff, num_entries * png_sizeof(png_byte)); for (i = 0; i < num_palette; i++) { int ir, ig, ib; - int r = (palette[i].red >> (8 - PNG_DITHER_RED_BITS)); - int g = (palette[i].green >> (8 - PNG_DITHER_GREEN_BITS)); - int b = (palette[i].blue >> (8 - PNG_DITHER_BLUE_BITS)); + 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_DITHER_BLUE_BITS + PNG_DITHER_GREEN_BITS)); + int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS + + PNG_QUANTIZE_GREEN_BITS)); for (ig = 0; ig < num_green; ig++) { @@ -510,7 +739,7 @@ png_set_dither(png_structp png_ptr, png_colorp palette, int dg = ((ig > g) ? ig - g : g - ig); int dt = dr + dg; int dm = ((dr > dg) ? dr : dg); - int index_g = index_r | (ig << PNG_DITHER_BLUE_BITS); + int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS); for (ib = 0; ib < num_blue; ib++) { @@ -533,35 +762,58 @@ png_set_dither(png_structp png_ptr, png_colorp palette, png_free(png_ptr, distance); } } -#endif +#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) +#ifdef PNG_READ_GAMMA_SUPPORTED +void PNGFAPI +png_set_gamma_fixed(png_structp png_ptr, png_fixed_point scrn_gamma, + png_fixed_point file_gamma) { - png_debug(1, "in png_set_gamma"); + png_debug(1, "in png_set_gamma_fixed"); 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; -} + /* New in libpng-1.5.4 - reserve particular negative values as flags. */ + scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/); + file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/); + +#if PNG_LIBPNG_VER >= 10600 + /* Checking the gamma values for being >0 was added in 1.5.4 along with the + * premultiplied alpha support; this actually hides an undocumented feature + * of the previous implementation which allowed gamma processing to be + * disabled in background handling. There is no evidence (so far) that this + * was being used; however, png_set_background itself accepted and must still + * accept '0' for the gamma value it takes, because it isn't always used. + * + * Since this is an API change (albeit a very minor one that removes an + * undocumented API feature) it will not be made until libpng-1.6.0. + */ + if (file_gamma <= 0) + png_error(png_ptr, "invalid file gamma in png_set_gamma"); + + if (scrn_gamma <= 0) + png_error(png_ptr, "invalid screen gamma in png_set_gamma"); #endif + /* Set the gamma values unconditionally - this overrides the value in the PNG + * file if a gAMA chunk was present. png_set_alpha_mode provides a + * different, easier, way to default the file gamma. + */ + png_ptr->gamma = file_gamma; + png_ptr->screen_gamma = scrn_gamma; +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma) +{ + png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma), + convert_gamma_value(png_ptr, file_gamma)); +} +# endif /* FLOATING_POINT_SUPPORTED */ +#endif /* READ_GAMMA */ + #ifdef PNG_READ_EXPAND_SUPPORTED /* Expand paletted images to RGB, expand grayscale images of * less than 8-bit depth to 8-bit depth, and expand tRNS chunks @@ -636,38 +888,46 @@ png_set_tRNS_to_alpha(png_structp png_ptr) } #endif /* defined(PNG_READ_EXPAND_SUPPORTED) */ -#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED +#ifdef PNG_READ_EXPAND_16_SUPPORTED +/* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise + * it may not work correctly.) + */ void PNGAPI -png_set_gray_to_rgb(png_structp png_ptr) +png_set_expand_16(png_structp png_ptr) { - png_debug(1, "in png_set_gray_to_rgb"); + png_debug(1, "in png_set_expand_16"); + + if (png_ptr == NULL) + return; - png_ptr->transformations |= PNG_GRAY_TO_RGB; + png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS); png_ptr->flags &= ~PNG_FLAG_ROW_INIT; + + /* New API, make sure apps call the correct initializers: */ + png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED; } #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. - */ - +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED void PNGAPI -png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red, - double green) +png_set_gray_to_rgb(png_structp png_ptr) { - 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); + png_debug(1, "in png_set_gray_to_rgb"); + + if (png_ptr != NULL) + { + /* Because rgb must be 8 bits or more: */ + png_set_expand_gray_1_2_4_to_8(png_ptr); + png_ptr->transformations |= PNG_GRAY_TO_RGB; + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; + } } #endif -void PNGAPI +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +void PNGFAPI png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action, - png_fixed_point red, png_fixed_point green) + png_fixed_point red, png_fixed_point green) { png_debug(1, "in png_set_rgb_to_gray"); @@ -676,13 +936,21 @@ png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action, switch(error_action) { - case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY; - break; + case 1: + png_ptr->transformations |= PNG_RGB_TO_GRAY; + break; - case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN; - break; + case 2: + png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN; + break; - case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR; + case 3: + png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR; + break; + + default: + png_error(png_ptr, "invalid error action to rgb_to_gray"); + break; } if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) #ifdef PNG_READ_EXPAND_SUPPORTED @@ -691,40 +959,71 @@ png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action, { 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) + if (red >= 0 && green >= 0 && red + green <= PNG_FP_1) { + png_uint_16 red_int, green_int; + red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L); green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L); + + 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); } + else { - png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients"); - red_int = 6968; - green_int = 23434; + if (red >= 0 && green >= 0) + png_warning(png_ptr, + "ignoring out of range rgb_to_gray coefficients"); + + /* Use the defaults, from the cHRM chunk if set, else the built in Rec + * 709 values (which correspond to sRGB, so we don't have to worry + * about the sRGB chunk!) + */ + if (png_ptr->rgb_to_gray_red_coeff == 0 && + png_ptr->rgb_to_gray_green_coeff == 0 && + png_ptr->rgb_to_gray_blue_coeff == 0) + { + png_ptr->rgb_to_gray_red_coeff = 6968; /* .212671 * 32768 + .5 */ + png_ptr->rgb_to_gray_green_coeff = 23434; /* .715160 * 32768 + .5 */ + png_ptr->rgb_to_gray_blue_coeff = 2366; + } } - 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); } } + +#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) +{ + if (png_ptr == NULL) + return; + + png_set_rgb_to_gray_fixed(png_ptr, error_action, + png_fixed(png_ptr, red, "rgb to gray red coefficient"), + png_fixed(png_ptr, green, "rgb to gray green coefficient")); +} +#endif /* FLOATING POINT */ + #endif #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) + read_user_transform_fn) { png_debug(1, "in png_set_read_user_transform_fn"); @@ -738,52 +1037,160 @@ png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr } #endif +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +#ifdef PNG_READ_GAMMA_SUPPORTED +/* In the case of gamma transformations only do transformations on images where + * the [file] gamma and screen_gamma are not close reciprocals, otherwise it + * slows things down slightly, and also needlessly introduces small errors. + */ +static int /* PRIVATE */ +png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma) +{ + /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma + * correction as a difference of the overall transform from 1.0 + * + * We want to compare the threshold with s*f - 1, if we get + * overflow here it is because of wacky gamma values so we + * turn on processing anyway. + */ + png_fixed_point gtest; + return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) || + png_gamma_significant(gtest); +} +#endif + /* Initialize everything needed for the read. This includes modifying * the palette. */ -void /* PRIVATE */ -png_init_read_transformations(png_structp png_ptr) + +/*For the moment 'png_init_palette_transformations' and + * 'png_init_rgb_transformations' only do some flag canceling optimizations. + * The intent is that these two routines should have palette or rgb operations + * extracted from 'png_init_read_transformations'. + */ +static void /* PRIVATE */ +png_init_palette_transformations(png_structp png_ptr) { - png_debug(1, "in png_init_read_transformations"); + /* Called to handle the (input) palette case. In png_do_read_transformations + * the first step is to expand the palette if requested, so this code must + * take care to only make changes that are invariant with respect to the + * palette expansion, or only do them if there is no expansion. + * + * STRIP_ALPHA has already been handled in the caller (by setting num_trans + * to 0.) + */ + int input_has_alpha = 0; + int input_has_transparency = 0; - { -#if defined(PNG_READ_BACKGROUND_SUPPORTED) || defined(PNG_READ_SHIFT_SUPPORTED) \ - || defined(PNG_READ_GAMMA_SUPPORTED) - int color_type = png_ptr->color_type; -#endif + if (png_ptr->num_trans > 0) + { + int i; + + /* Ignore if all the entries are opaque (unlikely!) */ + for (i=0; i<png_ptr->num_trans; ++i) + if (png_ptr->trans_alpha[i] == 255) + continue; + else if (png_ptr->trans_alpha[i] == 0) + input_has_transparency = 1; + else + input_has_alpha = 1; + } + + /* If no alpha we can optimize. */ + if (!input_has_alpha) + { + /* Any alpha means background and associative alpha processing is + * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA + * and ENCODE_ALPHA are irrelevant. + */ + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + + if (!input_has_transparency) + png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND); + } #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED) + /* png_set_background handling - deals with the complexity of whether the + * background color is in the file format or the screen format in the case + * where an 'expand' will happen. + */ -#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. + /* The following code cannot be entered in the alpha pre-multiplication case + * because PNG_BACKGROUND_EXPAND is cancelled below. */ if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) && - !(color_type & PNG_COLOR_MASK_COLOR)) + (png_ptr->transformations & PNG_EXPAND)) { - 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->background.red = + png_ptr->palette[png_ptr->background.index].red; + png_ptr->background.green = + png_ptr->palette[png_ptr->background.index].green; + png_ptr->background.blue = + png_ptr->palette[png_ptr->background.index].blue; + +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED + if (png_ptr->transformations & PNG_INVERT_ALPHA) + { + if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) + { + /* Invert the alpha channel (in tRNS) unless the pixels are + * going to be expanded, in which case leave it for later + */ + int i, istop = png_ptr->num_trans; + + for (i=0; i<istop; i++) + png_ptr->trans_alpha[i] = (png_byte)(255 - + png_ptr->trans_alpha[i]); + } + } +#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */ + } + } /* background expand and (therefore) no alpha association. */ +#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */ +} + +static void /* PRIVATE */ +png_init_rgb_transformations(png_structp png_ptr) +{ + /* Added to libpng-1.5.4: check the color type to determine whether there + * is any alpha or transparency in the image and simply cancel the + * background and alpha mode stuff if there isn't. + */ + int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0; + int input_has_transparency = png_ptr->num_trans > 0; + + /* If no alpha we can optimize. */ + if (!input_has_alpha) { - png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; - png_ptr->background.gray = png_ptr->background.red; + /* Any alpha means background and associative alpha processing is + * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA + * and ENCODE_ALPHA are irrelevant. + */ +# ifdef PNG_READ_ALPHA_MODE_SUPPORTED + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; +# endif + + if (!input_has_transparency) + png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND); } -#endif +#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED) + /* png_set_background handling - deals with the complexity of whether the + * background color is in the file format or the screen format in the case + * where an 'expand' will happen. + */ + + /* The following code cannot be entered in the alpha pre-multiplication case + * because PNG_BACKGROUND_EXPAND is cancelled below. + */ if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) && - (png_ptr->transformations & PNG_EXPAND)) + (png_ptr->transformations & PNG_EXPAND) && + !(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) + /* i.e., GRAY or GRAY_ALPHA */ { - if (!(color_type & PNG_COLOR_MASK_COLOR)) /* i.e., GRAY or GRAY_ALPHA */ { /* Expand background and tRNS chunks */ switch (png_ptr->bit_depth) @@ -791,115 +1198,336 @@ png_init_read_transformations(png_structp png_ptr) 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; + = 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; + = 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; + = 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; + 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; + = 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; + 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; + default: + case 8: case 16: png_ptr->background.red = png_ptr->background.green - = png_ptr->background.blue = png_ptr->background.gray; + = png_ptr->background.blue = png_ptr->background.gray; break; } } - else if (color_type == PNG_COLOR_TYPE_PALETTE) + } /* background expand and (therefore) no alpha association. */ +#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */ +} + +void /* PRIVATE */ +png_init_read_transformations(png_structp png_ptr) +{ + png_debug(1, "in png_init_read_transformations"); + + /* This internal function is called from png_read_start_row in pngrutil.c + * and it is called before the 'rowbytes' calculation is done, so the code + * in here can change or update the transformations flags. + * + * First do updates that do not depend on the details of the PNG image data + * being processed. + */ + +#ifdef PNG_READ_GAMMA_SUPPORTED + /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds + * png_set_alpha_mode and this is another source for a default file gamma so + * the test needs to be performed later - here. In addition prior to 1.5.4 + * the tests were repeated for the PALETTE color type here - this is no + * longer necessary (and doesn't seem to have been necessary before.) + */ + { + /* The following temporary indicates if overall gamma correction is + * required. + */ + int gamma_correction = 0; + + if (png_ptr->gamma != 0) /* has been set */ { - png_ptr->background.red = - png_ptr->palette[png_ptr->background.index].red; - png_ptr->background.green = - png_ptr->palette[png_ptr->background.index].green; - png_ptr->background.blue = - png_ptr->palette[png_ptr->background.index].blue; + if (png_ptr->screen_gamma != 0) /* screen set too */ + gamma_correction = png_gamma_threshold(png_ptr->gamma, + png_ptr->screen_gamma); -#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)) + else + /* Assume the output matches the input; a long time default behavior + * of libpng, although the standard has nothing to say about this. + */ + png_ptr->screen_gamma = png_reciprocal(png_ptr->gamma); + } + + else if (png_ptr->screen_gamma != 0) + /* The converse - assume the file matches the screen, note that this + * perhaps undesireable default can (from 1.5.4) be changed by calling + * png_set_alpha_mode (even if the alpha handling mode isn't required + * or isn't changed from the default.) + */ + png_ptr->gamma = png_reciprocal(png_ptr->screen_gamma); + + else /* neither are set */ + /* Just in case the following prevents any processing - file and screen + * are both assumed to be linear and there is no way to introduce a + * third gamma value other than png_set_background with 'UNIQUE', and, + * prior to 1.5.4 + */ + png_ptr->screen_gamma = png_ptr->gamma = PNG_FP_1; + + /* Now turn the gamma transformation on or off as appropriate. Notice + * that PNG_GAMMA just refers to the file->screen correction. Alpha + * composition may independently cause gamma correction because it needs + * linear data (e.g. if the file has a gAMA chunk but the screen gamma + * hasn't been specified.) In any case this flag may get turned off in + * the code immediately below if the transform can be handled outside the + * row loop. + */ + if (gamma_correction) + png_ptr->transformations |= PNG_GAMMA; + + else + png_ptr->transformations &= ~PNG_GAMMA; + } #endif - { - /* 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]); - } - } + + /* Certain transformations have the effect of preventing other + * transformations that happen afterward in png_do_read_transformations, + * resolve the interdependencies here. From the code of + * png_do_read_transformations the order is: + * + * 1) PNG_EXPAND (including PNG_EXPAND_tRNS) + * 2) PNG_STRIP_ALPHA (if no compose) + * 3) PNG_RGB_TO_GRAY + * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY + * 5) PNG_COMPOSE + * 6) PNG_GAMMA + * 7) PNG_STRIP_ALPHA (if compose) + * 8) PNG_ENCODE_ALPHA + * 9) PNG_SCALE_16_TO_8 + * 10) PNG_16_TO_8 + * 11) PNG_QUANTIZE (converts to palette) + * 12) PNG_EXPAND_16 + * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY + * 14) PNG_INVERT_MONO + * 15) PNG_SHIFT + * 16) PNG_PACK + * 17) PNG_BGR + * 18) PNG_PACKSWAP + * 19) PNG_FILLER (includes PNG_ADD_ALPHA) + * 20) PNG_INVERT_ALPHA + * 21) PNG_SWAP_ALPHA + * 22) PNG_SWAP_BYTES + * 23) PNG_USER_TRANSFORM [must be last] + */ +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + !(png_ptr->transformations & PNG_COMPOSE)) + { + /* Stripping the alpha channel happens immediately after the 'expand' + * transformations, before all other transformation, so it cancels out + * the alpha handling. It has the side effect negating the effect of + * PNG_EXPAND_tRNS too: + */ + png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA | + PNG_EXPAND_tRNS); + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + + /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen + * so transparency information would remain just so long as it wasn't + * expanded. This produces unexpected API changes if the set of things + * that do PNG_EXPAND_tRNS changes (perfectly possible given the + * documentation - which says ask for what you want, accept what you + * get.) This makes the behavior consistent from 1.5.4: + */ + png_ptr->num_trans = 0; + } +#endif /* STRIP_ALPHA supported, no COMPOSE */ + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED + /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA + * settings will have no effect. + */ + if (!png_gamma_significant(png_ptr->screen_gamma)) + { + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + } #endif +#if defined(PNG_READ_EXPAND_SUPPORTED) && \ + defined(PNG_READ_BACKGROUND_SUPPORTED) && \ + defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) + /* Detect gray background and attempt to enable optimization for + * gray --> RGB case. + * + * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or + * RGB_ALPHA (in which case need_expand is superfluous anyway), the + * background color might actually be gray yet not be flagged as such. + * This is not a problem for the current code, which uses + * PNG_BACKGROUND_IS_GRAY only to decide when to do the + * png_do_gray_to_rgb() transformation. + * + * TODO: this code needs to be revised to avoid the complexity and + * interdependencies. The color type of the background should be recorded in + * png_set_background, along with the bit depth, then the code has a record + * of exactly what color space the background is currently in. + */ + if (png_ptr->transformations & PNG_BACKGROUND_EXPAND) + { + /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if + * the file was greyscale the background value is gray. + */ + if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) + png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; + } + + else if (png_ptr->transformations & PNG_COMPOSE) + { + /* PNG_COMPOSE: png_set_background was called with need_expand false, + * so the color is in the color space of the output or png_set_alpha_mode + * was called and the color is black. Ignore RGB_TO_GRAY because that + * happens before GRAY_TO_RGB. + */ + if (png_ptr->transformations & PNG_GRAY_TO_RGB) + { + if (png_ptr->background.red == png_ptr->background.green && + png_ptr->background.red == png_ptr->background.blue) + { + png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; + png_ptr->background.gray = png_ptr->background.red; + } } } -#endif +#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED (etc) */ -#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) + /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations + * can be performed directly on the palette, and some (such as rgb to gray) + * can be optimized inside the palette. This is particularly true of the + * composite (background and alpha) stuff, which can be pretty much all done + * in the palette even if the result is expanded to RGB or gray afterward. + * + * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and + * earlier and the palette stuff is actually handled on the first row. This + * leads to the reported bug that the palette returned by png_get_PLTE is not + * updated. + */ + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + png_init_palette_transformations(png_ptr); - 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)) + else + png_init_rgb_transformations(png_ptr); + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ + defined(PNG_READ_EXPAND_16_SUPPORTED) + if ((png_ptr->transformations & PNG_EXPAND_16) && + (png_ptr->transformations & PNG_COMPOSE) && + !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + png_ptr->bit_depth != 16) { - 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; + /* TODO: fix this. Because the expand_16 operation is after the compose + * handling the background color must be 8, not 16, bits deep, but the + * application will supply a 16-bit value so reduce it here. + * + * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at + * present, so that case is ok (until do_expand_16 is moved.) + * + * NOTE: this discards the low 16 bits of the user supplied background + * color, but until expand_16 works properly there is no choice! + */ +# define CHOP(x) (x)=((png_uint_16)(((png_uint_32)(x)*255+32895) >> 16)) + CHOP(png_ptr->background.red); + CHOP(png_ptr->background.green); + CHOP(png_ptr->background.blue); + CHOP(png_ptr->background.gray); +# undef CHOP } +#endif /* PNG_READ_BACKGROUND_SUPPORTED && PNG_READ_EXPAND_16_SUPPORTED */ + + /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the + * background support (see the comments in scripts/pnglibconf.dfa), this + * allows pre-multiplication of the alpha channel to be implemented as + * compositing on black. This is probably sub-optimal and has been done in + * 1.5.4 betas simply to enable external critique and testing (i.e. to + * implement the new API quickly, without lots of internal changes.) + */ - if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) && - png_ptr->gamma != 0.0) +#ifdef PNG_READ_GAMMA_SUPPORTED +# ifdef PNG_READ_BACKGROUND_SUPPORTED + /* Includes ALPHA_MODE */ + png_ptr->background_1 = png_ptr->background; +# endif + + /* This needs to change - in the palette image case a whole set of tables are + * built when it would be quicker to just calculate the correct value for + * each palette entry directly. Also, the test is too tricky - why check + * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that + * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the + * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction + * the gamma tables will not be built even if composition is required on a + * gamma encoded value. + * + * In 1.5.4 this is addressed below by an additional check on the individual + * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the + * tables. + */ + if ((png_ptr->transformations & PNG_GAMMA) + || ((png_ptr->transformations & PNG_RGB_TO_GRAY) + && (png_gamma_significant(png_ptr->gamma) || + png_gamma_significant(png_ptr->screen_gamma))) + || ((png_ptr->transformations & PNG_COMPOSE) + && (png_gamma_significant(png_ptr->gamma) + || png_gamma_significant(png_ptr->screen_gamma) +# ifdef PNG_READ_BACKGROUND_SUPPORTED + || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE + && png_gamma_significant(png_ptr->background_gamma)) +# endif + )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) + && png_gamma_significant(png_ptr->screen_gamma)) + ) { png_build_gamma_table(png_ptr, png_ptr->bit_depth); #ifdef PNG_READ_BACKGROUND_SUPPORTED - if (png_ptr->transformations & PNG_BACKGROUND) + if (png_ptr->transformations & PNG_COMPOSE) { - if (color_type == PNG_COLOR_TYPE_PALETTE) + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { - /* Could skip if no transparency */ + /* We don't get to here unless there is a tRNS chunk with non-opaque + * entries - see the checking code at the start of this function. + */ png_color back, back_1; png_colorp palette = png_ptr->palette; int num_palette = png_ptr->num_palette; int i; if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE) { + back.red = png_ptr->gamma_table[png_ptr->background.red]; back.green = png_ptr->gamma_table[png_ptr->background.green]; back.blue = png_ptr->gamma_table[png_ptr->background.blue]; @@ -910,56 +1538,71 @@ png_init_read_transformations(png_structp png_ptr) } else { - double g, gs; + png_fixed_point g, gs; switch (png_ptr->background_gamma_type) { case PNG_BACKGROUND_GAMMA_SCREEN: g = (png_ptr->screen_gamma); - gs = 1.0; + gs = PNG_FP_1; break; case PNG_BACKGROUND_GAMMA_FILE: - g = 1.0 / (png_ptr->gamma); - gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); + g = png_reciprocal(png_ptr->gamma); + gs = png_reciprocal2(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); + g = png_reciprocal(png_ptr->background_gamma); + gs = png_reciprocal2(png_ptr->background_gamma, + png_ptr->screen_gamma); break; default: - g = 1.0; /* back_1 */ - gs = 1.0; /* back */ + g = PNG_FP_1; /* back_1 */ + gs = PNG_FP_1; /* back */ + break; } - if ( fabs(gs - 1.0) < PNG_GAMMA_THRESHOLD) + if (png_gamma_significant(gs)) + { + back.red = png_gamma_8bit_correct(png_ptr->background.red, + gs); + back.green = png_gamma_8bit_correct(png_ptr->background.green, + gs); + back.blue = png_gamma_8bit_correct(png_ptr->background.blue, + gs); + } + + else { back.red = (png_byte)png_ptr->background.red; back.green = (png_byte)png_ptr->background.green; back.blue = (png_byte)png_ptr->background.blue; } - else + + if (png_gamma_significant(g)) { - 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_gamma_8bit_correct(png_ptr->background.red, + g); + back_1.green = png_gamma_8bit_correct( + png_ptr->background.green, g); + back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue, + g); } - 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); + else + { + back_1.red = (png_byte)png_ptr->background.red; + back_1.green = (png_byte)png_ptr->background.green; + back_1.blue = (png_byte)png_ptr->background.blue; + } } + for (i = 0; i < num_palette; i++) { - if (i < (int)png_ptr->num_trans && png_ptr->trans_alpha[i] != 0xff) + if (i < (int)png_ptr->num_trans && + png_ptr->trans_alpha[i] != 0xff) { if (png_ptr->trans_alpha[i] == 0) { @@ -989,84 +1632,98 @@ png_init_read_transformations(png_structp png_ptr) 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. + + /* Prevent the transformations being done again. + * + * NOTE: this is highly dubious; it zaps the transformations in + * place. This seems inconsistent with the general treatment of the + * transformations elsewhere. */ - png_ptr->transformations &= ~PNG_BACKGROUND; - png_ptr->transformations &= ~PNG_GAMMA; - png_ptr->transformations |= PNG_STRIP_ALPHA; - } + png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA); + } /* color_type == PNG_COLOR_TYPE_PALETTE */ + /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */ - else - /* color_type != PNG_COLOR_TYPE_PALETTE */ + 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; + png_fixed_point g = PNG_FP_1; + png_fixed_point gs = PNG_FP_1; switch (png_ptr->background_gamma_type) { case PNG_BACKGROUND_GAMMA_SCREEN: - g = (png_ptr->screen_gamma); - gs = 1.0; + g = png_ptr->screen_gamma; + /* gs = PNG_FP_1; */ break; case PNG_BACKGROUND_GAMMA_FILE: - g = 1.0 / (png_ptr->gamma); - gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); + g = png_reciprocal(png_ptr->gamma); + gs = png_reciprocal2(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); + g = png_reciprocal(png_ptr->background_gamma); + gs = png_reciprocal2(png_ptr->background_gamma, + png_ptr->screen_gamma); break; + + default: + png_error(png_ptr, "invalid background gamma type"); } - 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); + png_ptr->background_1.gray = png_gamma_correct(png_ptr, + png_ptr->background.gray, g); + + png_ptr->background.gray = png_gamma_correct(png_ptr, + png_ptr->background.gray, gs); if ((png_ptr->background.red != png_ptr->background.green) || (png_ptr->background.red != png_ptr->background.blue) || (png_ptr->background.red != png_ptr->background.gray)) { /* RGB or RGBA with color background */ - 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); + png_ptr->background_1.red = png_gamma_correct(png_ptr, + png_ptr->background.red, g); + + png_ptr->background_1.green = png_gamma_correct(png_ptr, + png_ptr->background.green, g); + + png_ptr->background_1.blue = png_gamma_correct(png_ptr, + png_ptr->background.blue, g); + + png_ptr->background.red = png_gamma_correct(png_ptr, + png_ptr->background.red, gs); + + png_ptr->background.green = png_gamma_correct(png_ptr, + png_ptr->background.green, gs); + + png_ptr->background.blue = png_gamma_correct(png_ptr, + png_ptr->background.blue, gs); } + else { /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */ png_ptr->background_1.red = png_ptr->background_1.green - = png_ptr->background_1.blue = png_ptr->background_1.gray; + = png_ptr->background_1.blue = png_ptr->background_1.gray; + png_ptr->background.red = png_ptr->background.green - = png_ptr->background.blue = png_ptr->background.gray; + = png_ptr->background.blue = png_ptr->background.gray; } - } - } + } /* color_type != PNG_COLOR_TYPE_PALETTE */ + }/* png_ptr->transformations & PNG_BACKGROUND */ + else /* Transformation does not include PNG_BACKGROUND */ #endif /* PNG_READ_BACKGROUND_SUPPORTED */ - if (color_type == PNG_COLOR_TYPE_PALETTE) + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { png_colorp palette = png_ptr->palette; int num_palette = png_ptr->num_palette; int i; + /*NOTE: there are other transformations that should probably be in here + * too. + */ for (i = 0; i < num_palette; i++) { palette[i].red = png_ptr->gamma_table[palette[i].red]; @@ -1076,16 +1733,17 @@ png_init_read_transformations(png_structp png_ptr) /* Done the gamma correction. */ png_ptr->transformations &= ~PNG_GAMMA; - } + } /* color_type == PALETTE && !PNG_BACKGROUND transformation */ } #ifdef PNG_READ_BACKGROUND_SUPPORTED else #endif -#endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */ +#endif /* PNG_READ_GAMMA_SUPPORTED */ + #ifdef PNG_READ_BACKGROUND_SUPPORTED - /* No GAMMA transformation */ - if ((png_ptr->transformations & PNG_BACKGROUND) && - (color_type == PNG_COLOR_TYPE_PALETTE)) + /* No GAMMA transformation (see the hanging else 4 lines above) */ + if ((png_ptr->transformations & PNG_COMPOSE) && + (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)) { int i; int istop = (int)png_ptr->num_trans; @@ -1102,27 +1760,28 @@ png_init_read_transformations(png_structp png_ptr) { 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_ptr->trans_alpha[i], back.red); + png_composite(palette[i].green, palette[i].green, - png_ptr->trans_alpha[i], back.green); + png_ptr->trans_alpha[i], back.green); + png_composite(palette[i].blue, palette[i].blue, - png_ptr->trans_alpha[i], back.blue); + png_ptr->trans_alpha[i], back.blue); } } - /* Handled alpha, still need to strip the channel. */ - png_ptr->transformations &= ~PNG_BACKGROUND; - png_ptr->transformations |= PNG_STRIP_ALPHA; + png_ptr->transformations &= ~PNG_COMPOSE; } #endif /* PNG_READ_BACKGROUND_SUPPORTED */ #ifdef PNG_READ_SHIFT_SUPPORTED if ((png_ptr->transformations & PNG_SHIFT) && - (color_type == PNG_COLOR_TYPE_PALETTE)) + (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)) { png_uint_16 i; png_uint_16 istop = png_ptr->num_palette; @@ -1132,10 +1791,13 @@ png_init_read_transformations(png_structp png_ptr) 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; @@ -1144,12 +1806,6 @@ png_init_read_transformations(png_structp png_ptr) } } #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 @@ -1166,11 +1822,16 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) { if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { - if (png_ptr->num_trans && - (png_ptr->transformations & PNG_EXPAND_tRNS)) + /* This check must match what actually happens in + * png_do_expand_palette; if it ever checks the tRNS chunk to see if + * it is all opaque we must do the same (at present it does not.) + */ + if (png_ptr->num_trans > 0) info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA; + else info_ptr->color_type = PNG_COLOR_TYPE_RGB; + info_ptr->bit_depth = 8; info_ptr->num_trans = 0; } @@ -1179,40 +1840,71 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) if (png_ptr->num_trans) { if (png_ptr->transformations & PNG_EXPAND_tRNS) - info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; + 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; +#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) + /* The following is almost certainly wrong unless the background value is in + * the screen space! + */ + if (png_ptr->transformations & PNG_COMPOSE) info_ptr->background = png_ptr->background; - } #endif #ifdef PNG_READ_GAMMA_SUPPORTED - 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 - } + /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4), + * however it seems that the code in png_init_read_transformations, which has + * been called before this from png_read_update_info->png_read_start_row + * sometimes does the gamma transform and cancels the flag. + */ + info_ptr->gamma = png_ptr->gamma; #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 + if (info_ptr->bit_depth == 16) + { +# ifdef PNG_READ_16BIT_SUPPORTED +# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_SCALE_16_TO_8) + info_ptr->bit_depth = 8; +# endif + +# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_16_TO_8) + info_ptr->bit_depth = 8; +# endif + +# else + /* No 16 bit support: force chopping 16-bit input down to 8, in this case + * the app program can chose if both APIs are available by setting the + * correct scaling to use. + */ +# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED + /* For compatibility with previous versions use the strip method by + * default. This code works because if PNG_SCALE_16_TO_8 is already + * set the code below will do that in preference to the chop. + */ + png_ptr->transformations |= PNG_16_TO_8; + info_ptr->bit_depth = 8; +# else + +# if PNG_READ_SCALE_16_TO_8_SUPPORTED + png_ptr->transformations |= PNG_SCALE_16_TO_8; + info_ptr->bit_depth = 8; +# else + + CONFIGURATION ERROR: you must enable at least one 16 to 8 method +# endif +# endif +#endif /* !READ_16BIT_SUPPORTED */ + } #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED if (png_ptr->transformations & PNG_GRAY_TO_RGB) @@ -1224,8 +1916,8 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR; #endif -#ifdef PNG_READ_DITHER_SUPPORTED - if (png_ptr->transformations & PNG_DITHER) +#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)) && @@ -1236,6 +1928,14 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) } #endif +#ifdef PNG_READ_EXPAND_16_SUPPORTED + if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 && + info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) + { + info_ptr->bit_depth = 16; + } +#endif + #ifdef PNG_READ_PACK_SUPPORTED if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8)) info_ptr->bit_depth = 8; @@ -1243,14 +1943,19 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) 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) + if (png_ptr->transformations & PNG_STRIP_ALPHA) + { info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA; + info_ptr->num_trans = 0; + } #endif if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA) @@ -1265,26 +1970,35 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) 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; + 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) + { + 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) + + 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->bit_depth); info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width); + /* Adding in 1.5.4: cache the above value in png_struct so that we can later + * check in png_rowbytes that the user buffer won't get overwritten. Note + * that the field is not always set - if png_read_update_info isn't called + * the application has to either not do any transforms or get the calculation + * right itself. + */ + png_ptr->info_rowbytes = info_ptr->rowbytes; + #ifndef PNG_READ_EXPAND_SUPPORTED if (png_ptr) return; @@ -1302,29 +2016,27 @@ png_do_read_transformations(png_structp png_ptr) 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 + /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this + * error is incredibly rare and incredibly easy to debug without this + * information. + */ png_error(png_ptr, "NULL row buffer"); -#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 + + /* The following is debugging; prior to 1.5.4 the code was never compiled in; + * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro + * PNG_WARN_UNINITIALIZED_ROW removed. In 1.5 the new flag is set only for + * selected new APIs to ensure that there is no API change. + */ + if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 && + !(png_ptr->flags & PNG_FLAG_ROW_INIT)) + { + /* Application has failed to call either png_read_start_image() or + * png_read_update_info() after setting transforms that expand pixels. + * This check added to libpng-1.2.19 (but not enabled until 1.5.4). */ -#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) @@ -1332,38 +2044,46 @@ png_do_read_transformations(png_structp png_ptr) 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); + 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)); + &(png_ptr->trans_color)); + else png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, - NULL); + 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)); + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + !(png_ptr->transformations & PNG_COMPOSE) && + (png_ptr->row_info.color_type == PNG_COLOR_TYPE_RGB_ALPHA || + png_ptr->row_info.color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) + png_do_strip_channel(&(png_ptr->row_info), png_ptr->row_buf + 1, + 0 /* at_start == false, because SWAP_ALPHA happens later */); #endif #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED if (png_ptr->transformations & PNG_RGB_TO_GRAY) { int rgb_error = - png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info), png_ptr->row_buf + 1); + 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"); @@ -1411,48 +2131,79 @@ png_do_read_transformations(png_structp png_ptr) 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 -); +#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\ + (defined PNG_READ_ALPHA_MODE_SUPPORTED) + if (png_ptr->transformations & PNG_COMPOSE) + png_do_compose(&(png_ptr->row_info), png_ptr->row_buf + 1, png_ptr); #endif #ifdef PNG_READ_GAMMA_SUPPORTED if ((png_ptr->transformations & PNG_GAMMA) && -#ifdef PNG_READ_BACKGROUND_SUPPORTED - !((png_ptr->transformations & PNG_BACKGROUND) && +#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\ + (defined PNG_READ_ALPHA_MODE_SUPPORTED) + !((png_ptr->transformations & PNG_COMPOSE) && ((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); + png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1, png_ptr); #endif -#ifdef PNG_READ_16_TO_8_SUPPORTED +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + (png_ptr->transformations & PNG_COMPOSE) && + (png_ptr->row_info.color_type == PNG_COLOR_TYPE_RGB_ALPHA || + png_ptr->row_info.color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) + png_do_strip_channel(&(png_ptr->row_info), png_ptr->row_buf + 1, + 0 /* at_start == false, because SWAP_ALPHA happens later */); +#endif + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED + if ((png_ptr->transformations & PNG_ENCODE_ALPHA) && + (png_ptr->row_info.color_type & PNG_COLOR_MASK_ALPHA)) + png_do_encode_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1, png_ptr); +#endif + +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_SCALE_16_TO_8) + png_do_scale_16_to_8(&(png_ptr->row_info), png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED + /* There is no harm in doing both of these because only one has any effect, + * by putting the 'scale' option first if the app asks for scale (either by + * calling the API or in a TRANSFORM flag) this is what happens. + */ if (png_ptr->transformations & PNG_16_TO_8) png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif -#ifdef PNG_READ_DITHER_SUPPORTED - if (png_ptr->transformations & PNG_DITHER) +#ifdef PNG_READ_QUANTIZE_SUPPORTED + if (png_ptr->transformations & PNG_QUANTIZE) { - png_do_dither((png_row_infop)&(png_ptr->row_info), png_ptr->row_buf + 1, - png_ptr->palette_lookup, png_ptr->dither_index); - if (png_ptr->row_info.rowbytes == (png_uint_32)0) - png_error(png_ptr, "png_do_dither returned rowbytes=0"); + png_do_quantize(&(png_ptr->row_info), png_ptr->row_buf + 1, + png_ptr->palette_lookup, png_ptr->quantize_index); + + if (png_ptr->row_info.rowbytes == 0) + png_error(png_ptr, "png_do_quantize returned rowbytes=0"); } +#endif /* PNG_READ_QUANTIZE_SUPPORTED */ + +#ifdef PNG_READ_EXPAND_16_SUPPORTED + /* Do the expansion now, after all the arithmetic has been done. Notice + * that previous transformations can handle the PNG_EXPAND_16 flag if this + * is efficient (particularly true in the case of gamma correction, where + * better accuracy results faster!) + */ + if (png_ptr->transformations & PNG_EXPAND_16) + png_do_expand_16(&png_ptr->row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + /*NOTE: moved here in 1.5.4 (from much later in this list.) */ + if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && + (png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) + png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif #ifdef PNG_READ_INVERT_SUPPORTED @@ -1463,7 +2214,7 @@ png_do_read_transformations(png_structp png_ptr) #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)); + &(png_ptr->shift)); #endif #ifdef PNG_READ_PACK_SUPPORTED @@ -1481,17 +2232,10 @@ png_do_read_transformations(png_structp png_ptr) 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); + (png_uint_32)png_ptr->filler, png_ptr->flags); #endif #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED @@ -1504,38 +2248,41 @@ png_do_read_transformations(png_structp png_ptr) png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif +#ifdef PNG_READ_16BIT_SUPPORTED #ifdef PNG_READ_SWAP_SUPPORTED if (png_ptr->transformations & PNG_SWAP_BYTES) png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1); #endif +#endif #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED if (png_ptr->transformations & PNG_USER_TRANSFORM) { if (png_ptr->read_user_transform_fn != NULL) (*(png_ptr->read_user_transform_fn)) /* User read transform function */ - (png_ptr, /* png_ptr */ - &(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 */ + (png_ptr, /* png_ptr */ + &(png_ptr->row_info), /* row_info: */ + /* png_uint_32 width; width of row */ + /* png_size_t rowbytes; number of bytes in row */ + /* png_byte color_type; color type of pixels */ + /* png_byte bit_depth; bit depth of samples */ + /* png_byte channels; number of channels (1-4) */ + /* png_byte pixel_depth; bits per pixel (depth*channels) */ + png_ptr->row_buf + 1); /* start of pixel data for row */ #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED if (png_ptr->user_transform_depth) 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.channels); + png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth, - png_ptr->row_info.width); + png_ptr->row_info.width); } #endif - } #ifdef PNG_READ_PACK_SUPPORTED @@ -1565,11 +2312,13 @@ png_do_unpack(png_row_infop row_info, png_bytep row) for (i = 0; i < row_width; i++) { *dp = (png_byte)((*sp >> shift) & 0x01); + if (shift == 7) { shift = 0; sp--; } + else shift++; @@ -1587,11 +2336,13 @@ png_do_unpack(png_row_infop row_info, png_bytep row) for (i = 0; i < row_width; i++) { *dp = (png_byte)((*sp >> shift) & 0x03); + if (shift == 6) { shift = 0; sp--; } + else shift += 2; @@ -1608,11 +2359,13 @@ png_do_unpack(png_row_infop row_info, png_bytep row) for (i = 0; i < row_width; i++) { *dp = (png_byte)((*sp >> shift) & 0x0f); + if (shift == 4) { shift = 0; sp--; } + else shift = 4; @@ -1620,6 +2373,9 @@ png_do_unpack(png_row_infop row_info, png_bytep row) } break; } + + default: + break; } row_info->bit_depth = 8; row_info->pixel_depth = (png_byte)(8 * row_info->channels); @@ -1635,7 +2391,8 @@ png_do_unpack(png_row_infop row_info, png_bytep row) * 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_do_unshift(png_row_infop row_info, png_bytep row, + png_const_color_8p sig_bits) { png_debug(1, "in png_do_unshift"); @@ -1654,10 +2411,12 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) 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; @@ -1667,6 +2426,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) { if (shift[c] <= 0) shift[c] = 0; + else value = 1; } @@ -1676,11 +2436,14 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) switch (row_info->bit_depth) { + default: + break; + case 2: { png_bytep bp; - png_uint_32 i; - png_uint_32 istop = row_info->rowbytes; + png_size_t i; + png_size_t istop = row_info->rowbytes; for (bp = row, i = 0; i < istop; i++) { @@ -1693,10 +2456,10 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) case 4: { png_bytep bp = row; - png_uint_32 i; - png_uint_32 istop = row_info->rowbytes; + png_size_t i; + png_size_t istop = row_info->rowbytes; png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) | - (png_byte)((int)0xf >> shift[0])); + (png_byte)((int)0xf >> shift[0])); for (i = 0; i < istop; i++) { @@ -1719,6 +2482,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) break; } +#ifdef PNG_READ_16BIT_SUPPORTED case 16: { png_bytep bp = row; @@ -1734,59 +2498,92 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) } break; } +#endif } } } #endif -#ifdef PNG_READ_16_TO_8_SUPPORTED -/* Chop rows of bit depth 16 down to 8 */ +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED +/* Scale rows of bit depth 16 down to 8 accurately */ void /* PRIVATE */ -png_do_chop(png_row_infop row_info, png_bytep row) +png_do_scale_16_to_8(png_row_infop row_info, png_bytep row) { - png_debug(1, "in png_do_chop"); + png_debug(1, "in png_do_scale_16_to_8"); 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; + png_bytep sp = row; /* source */ + png_bytep dp = row; /* destinaton */ + png_bytep ep = sp + row_info->rowbytes; /* end+1 */ - for (i = 0; i<istop; i++, sp += 2, dp++) + while (sp < ep) { -#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: - */ + /* The input is an array of 16 bit components, these must be scaled to + * 8 bits each. For a 16 bit value V the required value (from the PNG + * specification) is: + * + * (V * 255) / 65535 + * + * This reduces to round(V / 257), or floor((V + 128.5)/257) + * + * Represent V as the two byte value vhi.vlo. Make a guess that the + * result is the top byte of V, vhi, then the correction to this value + * is: + * + * error = floor(((V-vhi.vhi) + 128.5) / 257) + * = floor(((vlo-vhi) + 128.5) / 257) + * + * This can be approximated using integer arithmetic (and a signed + * shift): + * + * error = (vlo-vhi+128) >> 8; + * + * The approximate differs from the exact answer only when (vlo-vhi) is + * 128; it then gives a correction of +1 when the exact correction is + * 0. This gives 128 errors. The exact answer (correct for all 16 bit + * input values) is: + * + * error = (vlo-vhi+128)*65535 >> 24; + * + * An alternative arithmetic calculation which also gives no errors is: + * + * (V * 255 + 32895) >> 16 + */ - *dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0); -#else - /* Simply discard the low order byte */ - *dp = *sp; + png_int_32 tmp = *sp++; /* must be signed! */ + tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24; + *dp++ = (png_byte)tmp; + } + + row_info->bit_depth = 8; + row_info->pixel_depth = (png_byte)(8 * row_info->channels); + row_info->rowbytes = row_info->width * row_info->channels; + } +} #endif + +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED +void /* PRIVATE */ +/* Simply discard the low byte. This was the default behavior prior + * to libpng-1.5.4. + */ +png_do_chop(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_chop"); + + if (row_info->bit_depth == 16) + { + png_bytep sp = row; /* source */ + png_bytep dp = row; /* destinaton */ + png_bytep ep = sp + row_info->rowbytes; /* end+1 */ + + while (sp < ep) + { + *dp++ = *sp; + sp += 2; /* skip low byte */ } + row_info->bit_depth = 8; row_info->pixel_depth = (png_byte)(8 * row_info->channels); row_info->rowbytes = row_info->width * row_info->channels; @@ -1821,6 +2618,8 @@ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) *(--dp) = save; } } + +#ifdef PNG_READ_16BIT_SUPPORTED /* This converts from RRGGBBAA to AARRGGBB */ else { @@ -1843,7 +2642,9 @@ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) *(--dp) = save[1]; } } +#endif } + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { /* This converts from GA to AG */ @@ -1861,6 +2662,8 @@ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) *(--dp) = save; } } + +#ifdef PNG_READ_16BIT_SUPPORTED /* This converts from GGAA to AAGG */ else { @@ -1879,6 +2682,7 @@ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) *(--dp) = save[1]; } } +#endif } } } @@ -1888,94 +2692,99 @@ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) void /* PRIVATE */ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row) { + png_uint_32 row_width; png_debug(1, "in png_do_read_invert_alpha"); + row_width = row_info->width; + if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { - png_uint_32 row_width = row_info->width; - if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + if (row_info->bit_depth == 8) { /* This inverts the alpha channel in RGBA */ - if (row_info->bit_depth == 8) - { - png_bytep sp = row + row_info->rowbytes; - png_bytep dp = sp; - png_uint_32 i; + 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)); + 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: +/* This does nothing: + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + We can replace it with: */ - sp-=3; - dp=sp; - } + 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)); +#ifdef PNG_READ_16BIT_SUPPORTED + /* This inverts the alpha channel in RRGGBBAA */ + else + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_uint_32 i; -/* This does nothing: - *(--dp) = *(--sp); - *(--dp) = *(--sp); - *(--dp) = *(--sp); - *(--dp) = *(--sp); - *(--dp) = *(--sp); - *(--dp) = *(--sp); - We can replace it with: + 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; - } + sp-=6; + dp=sp; } } - else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) +#endif + } + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + if (row_info->bit_depth == 8) { /* This inverts the alpha channel in GA */ - if (row_info->bit_depth == 8) - { - png_bytep sp = row + row_info->rowbytes; - png_bytep dp = sp; - png_uint_32 i; + 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); - } + for (i = 0; i < row_width; i++) + { + *(--dp) = (png_byte)(255 - *(--sp)); + *(--dp) = *(--sp); } + } + +#ifdef PNG_READ_16BIT_SUPPORTED + else + { /* This inverts the alpha channel in GGAA */ - else - { - png_bytep sp = row + row_info->rowbytes; - png_bytep dp = sp; - png_uint_32 i; + 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)); + for (i = 0; i < row_width; i++) + { + *(--dp) = (png_byte)(255 - *(--sp)); + *(--dp) = (png_byte)(255 - *(--sp)); /* - *(--dp) = *(--sp); - *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); */ - sp-=2; - dp=sp; - } + sp-=2; + dp=sp; } } +#endif } } #endif @@ -1984,12 +2793,14 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row) /* 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 filler, png_uint_32 flags) { png_uint_32 i; png_uint_32 row_width = row_info->width; +#ifdef PNG_READ_16BIT_SUPPORTED png_byte hi_filler = (png_byte)((filler>>8) & 0xff); +#endif png_byte lo_filler = (png_byte)(filler & 0xff); png_debug(1, "in png_do_read_filler"); @@ -1999,9 +2810,9 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, { if (row_info->bit_depth == 8) { - /* This changes the data from G to GX */ if (flags & PNG_FLAG_FILLER_AFTER) { + /* This changes the data from G to GX */ png_bytep sp = row + (png_size_t)row_width; png_bytep dp = sp + (png_size_t)row_width; for (i = 1; i < row_width; i++) @@ -2014,9 +2825,10 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, row_info->pixel_depth = 16; row_info->rowbytes = row_width * 2; } - /* This changes the data from G to XG */ + else { + /* This changes the data from G to XG */ png_bytep sp = row + (png_size_t)row_width; png_bytep dp = sp + (png_size_t)row_width; for (i = 0; i < row_width; i++) @@ -2029,11 +2841,13 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, row_info->rowbytes = row_width * 2; } } + +#ifdef PNG_READ_16BIT_SUPPORTED else if (row_info->bit_depth == 16) { - /* This changes the data from GG to GGXX */ if (flags & PNG_FLAG_FILLER_AFTER) { + /* This changes the data from GG to GGXX */ png_bytep sp = row + (png_size_t)row_width * 2; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 1; i < row_width; i++) @@ -2049,9 +2863,10 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, row_info->pixel_depth = 32; row_info->rowbytes = row_width * 4; } - /* This changes the data from GG to XXGG */ + else { + /* This changes the data from GG to XXGG */ png_bytep sp = row + (png_size_t)row_width * 2; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 0; i < row_width; i++) @@ -2066,14 +2881,15 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, row_info->rowbytes = row_width * 4; } } +#endif } /* COLOR_TYPE == GRAY */ else if (row_info->color_type == PNG_COLOR_TYPE_RGB) { if (row_info->bit_depth == 8) { - /* This changes the data from RGB to RGBX */ if (flags & PNG_FLAG_FILLER_AFTER) { + /* This changes the data from RGB to RGBX */ png_bytep sp = row + (png_size_t)row_width * 3; png_bytep dp = sp + (png_size_t)row_width; for (i = 1; i < row_width; i++) @@ -2088,9 +2904,10 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, row_info->pixel_depth = 32; row_info->rowbytes = row_width * 4; } - /* This changes the data from RGB to XRGB */ + else { + /* This changes the data from RGB to XRGB */ png_bytep sp = row + (png_size_t)row_width * 3; png_bytep dp = sp + (png_size_t)row_width; for (i = 0; i < row_width; i++) @@ -2105,11 +2922,13 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, row_info->rowbytes = row_width * 4; } } + +#ifdef PNG_READ_16BIT_SUPPORTED else if (row_info->bit_depth == 16) { - /* This changes the data from RRGGBB to RRGGBBXX */ if (flags & PNG_FLAG_FILLER_AFTER) { + /* This changes the data from RRGGBB to RRGGBBXX */ png_bytep sp = row + (png_size_t)row_width * 6; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 1; i < row_width; i++) @@ -2129,9 +2948,10 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, row_info->pixel_depth = 64; row_info->rowbytes = row_width * 8; } - /* This changes the data from RRGGBB to XXRRGGBB */ + else { + /* This changes the data from RRGGBB to XXRRGGBB */ png_bytep sp = row + (png_size_t)row_width * 6; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 0; i < row_width; i++) @@ -2145,11 +2965,13 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, *(--dp) = hi_filler; *(--dp) = lo_filler; } + row_info->channels = 4; row_info->pixel_depth = 64; row_info->rowbytes = row_width * 8; } } +#endif } /* COLOR_TYPE == RGB */ } #endif @@ -2165,12 +2987,13 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) png_debug(1, "in png_do_gray_to_rgb"); if (row_info->bit_depth >= 8 && - !(row_info->color_type & PNG_COLOR_MASK_COLOR)) + !(row_info->color_type & PNG_COLOR_MASK_COLOR)) { if (row_info->color_type == PNG_COLOR_TYPE_GRAY) { if (row_info->bit_depth == 8) { + /* This changes G to RGB */ png_bytep sp = row + (png_size_t)row_width - 1; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 0; i < row_width; i++) @@ -2180,8 +3003,10 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) *(dp--) = *(sp--); } } + else { + /* This changes GG to RRGGBB */ png_bytep sp = row + (png_size_t)row_width * 2 - 1; png_bytep dp = sp + (png_size_t)row_width * 4; for (i = 0; i < row_width; i++) @@ -2195,10 +3020,12 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) } } } + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { if (row_info->bit_depth == 8) { + /* This changes GA to RGBA */ png_bytep sp = row + (png_size_t)row_width * 2 - 1; png_bytep dp = sp + (png_size_t)row_width * 2; for (i = 0; i < row_width; i++) @@ -2209,8 +3036,10 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) *(dp--) = *(sp--); } } + else { + /* This changes GGAA to RRGGBBAA */ png_bytep sp = row + (png_size_t)row_width * 4 - 1; png_bytep dp = sp + (png_size_t)row_width * 4; for (i = 0; i < row_width; i++) @@ -2229,7 +3058,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) 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->bit_depth); row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); } } @@ -2268,8 +3097,8 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) png_debug(1, "in png_do_rgb_to_gray"); - if ( - (row_info->color_type & PNG_COLOR_MASK_COLOR)) + if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) && + (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; @@ -2290,12 +3119,14 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) 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]; + (rc*red + gc*green + bc*blue)>>15]; } + else *(dp++) = *(sp - 1); } @@ -2310,11 +3141,13 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) 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); } @@ -2333,22 +3166,24 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) { 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; + 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 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); + + bc*blue_1)>>15); w = png_ptr->gamma_16_from_1[(gray16&0xff) >> png_ptr->gamma_shift][gray16 >> 8]; rgb_error |= 1; @@ -2367,12 +3202,13 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) { 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; + 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); @@ -2394,10 +3230,13 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) 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]; + [(rc*red + gc*green + bc*blue)>>15]; + *(dp++) = *(sp++); /* alpha */ } } @@ -2413,6 +3252,7 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) 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 */ } @@ -2430,24 +3270,31 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) { 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; + 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_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_ptr->gamma_shift][blue>>8]; + png_uint_16 gray16 = (png_uint_16)((rc * red_1 - + gc * green_1 + bc * blue_1)>>15); + + 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; } @@ -2465,11 +3312,13 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep 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; + 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); @@ -2479,20 +3328,23 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) } } } - row_info->channels -= (png_byte)2; - row_info->color_type &= ~PNG_COLOR_MASK_COLOR; + row_info->channels -= 2; + row_info->color_type = (png_byte)(row_info->color_type & + ~PNG_COLOR_MASK_COLOR); row_info->pixel_depth = (png_byte)(row_info->channels * - row_info->bit_depth); + row_info->bit_depth); row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); } return rgb_error; } #endif +#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ +#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED /* Build a grayscale palette. Palette is assumed to be 1 << bit_depth * large of png_color. This lets grayscale images be treated as * paletted. Most useful for gamma correction and simplification - * of code. + * of code. This API is not used internally. */ void PNGAPI png_build_grayscale_palette(int bit_depth, png_colorp palette) @@ -2542,34 +3394,36 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette) palette[i].blue = (png_byte)v; } } +#endif +#ifdef PNG_READ_TRANSFORMS_SUPPORTED #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 +png_do_compose(png_row_infop row_info, png_bytep row, png_structp png_ptr) +{ #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 + png_const_bytep gamma_table = png_ptr->gamma_table; + png_const_bytep gamma_from_1 = png_ptr->gamma_from_1; + png_const_bytep gamma_to_1 = png_ptr->gamma_to_1; + png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table; + png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1; + png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1; + int gamma_shift = png_ptr->gamma_shift; #endif - ) -{ - png_bytep sp, dp; + + png_bytep sp; png_uint_32 i; - png_uint_32 row_width=row_info->width; + png_uint_32 row_width = row_info->width; + int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0; int shift; - png_debug(1, "in png_do_background"); + png_debug(1, "in png_do_compose"); - 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) { @@ -2584,16 +3438,18 @@ png_do_background(png_row_infop row_info, png_bytep row, for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x01) - == trans_color->gray) + == png_ptr->trans_color.gray) { *sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff); - *sp |= (png_byte)(background->gray << shift); + *sp |= (png_byte)(png_ptr->background.gray << shift); } + if (!shift) { shift = 7; sp++; } + else shift--; } @@ -2610,11 +3466,12 @@ png_do_background(png_row_infop row_info, png_bytep row, for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x03) - == trans_color->gray) + == png_ptr->trans_color.gray) { *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff); - *sp |= (png_byte)(background->gray << shift); + *sp |= (png_byte)(png_ptr->background.gray << shift); } + else { png_byte p = (png_byte)((*sp >> shift) & 0x03); @@ -2623,15 +3480,18 @@ png_do_background(png_row_infop row_info, png_bytep row, *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff); *sp |= (png_byte)(g << shift); } + if (!shift) { shift = 6; sp++; } + else shift -= 2; } } + else #endif { @@ -2640,16 +3500,18 @@ png_do_background(png_row_infop row_info, png_bytep row, for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x03) - == trans_color->gray) + == png_ptr->trans_color.gray) { *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff); - *sp |= (png_byte)(background->gray << shift); + *sp |= (png_byte)(png_ptr->background.gray << shift); } + if (!shift) { shift = 6; sp++; } + else shift -= 2; } @@ -2667,28 +3529,32 @@ png_do_background(png_row_infop row_info, png_bytep row, for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x0f) - == trans_color->gray) + == png_ptr->trans_color.gray) { *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff); - *sp |= (png_byte)(background->gray << shift); + *sp |= (png_byte)(png_ptr->background.gray << shift); } + else { png_byte p = (png_byte)((*sp >> shift) & 0x0f); png_byte g = (png_byte)((gamma_table[p | - (p << 4)] >> 4) & 0x0f); + (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 { @@ -2697,16 +3563,18 @@ png_do_background(png_row_infop row_info, png_bytep row, for (i = 0; i < row_width; i++) { if ((png_uint_16)((*sp >> shift) & 0x0f) - == trans_color->gray) + == png_ptr->trans_color.gray) { *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff); - *sp |= (png_byte)(background->gray << shift); + *sp |= (png_byte)(png_ptr->background.gray << shift); } + if (!shift) { shift = 4; sp++; } + else shift -= 4; } @@ -2722,14 +3590,11 @@ png_do_background(png_row_infop row_info, png_bytep row, sp = row; for (i = 0; i < row_width; i++, sp++) { - if (*sp == trans_color->gray) - { - *sp = (png_byte)background->gray; - } + if (*sp == png_ptr->trans_color.gray) + *sp = (png_byte)png_ptr->background.gray; + else - { *sp = gamma_table[*sp]; - } } } else @@ -2738,10 +3603,8 @@ png_do_background(png_row_infop row_info, png_bytep row, sp = row; for (i = 0; i < row_width; i++, sp++) { - if (*sp == trans_color->gray) - { - *sp = (png_byte)background->gray; - } + if (*sp == png_ptr->trans_color.gray) + *sp = (png_byte)png_ptr->background.gray; } } break; @@ -2758,12 +3621,14 @@ png_do_background(png_row_infop row_info, png_bytep row, png_uint_16 v; v = (png_uint_16)(((*sp) << 8) + *(sp + 1)); - if (v == trans_color->gray) + + if (v == png_ptr->trans_color.gray) { /* Background is already in screen gamma */ - *sp = (png_byte)((background->gray >> 8) & 0xff); - *(sp + 1) = (png_byte)(background->gray & 0xff); + *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); } + else { v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; @@ -2781,15 +3646,19 @@ png_do_background(png_row_infop row_info, png_bytep row, png_uint_16 v; v = (png_uint_16)(((*sp) << 8) + *(sp + 1)); - if (v == trans_color->gray) + + if (v == png_ptr->trans_color.gray) { - *sp = (png_byte)((background->gray >> 8) & 0xff); - *(sp + 1) = (png_byte)(background->gray & 0xff); + *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); } } } break; } + + default: + break; } break; } @@ -2804,14 +3673,15 @@ png_do_background(png_row_infop row_info, png_bytep row, 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) + if (*sp == png_ptr->trans_color.red && + *(sp + 1) == png_ptr->trans_color.green && + *(sp + 2) == png_ptr->trans_color.blue) { - *sp = (png_byte)background->red; - *(sp + 1) = (png_byte)background->green; - *(sp + 2) = (png_byte)background->blue; + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; } + else { *sp = gamma_table[*sp]; @@ -2826,13 +3696,13 @@ png_do_background(png_row_infop row_info, png_bytep row, 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) + if (*sp == png_ptr->trans_color.red && + *(sp + 1) == png_ptr->trans_color.green && + *(sp + 2) == png_ptr->trans_color.blue) { - *sp = (png_byte)background->red; - *(sp + 1) = (png_byte)background->green; - *(sp + 2) = (png_byte)background->blue; + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; } } } @@ -2846,52 +3716,67 @@ png_do_background(png_row_infop row_info, png_bytep 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) + + png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8) + + *(sp + 3)); + + png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8) + + *(sp + 5)); + + if (r == png_ptr->trans_color.red && + g == png_ptr->trans_color.green && + b == png_ptr->trans_color.blue) { /* Background is already in screen gamma */ - *sp = (png_byte)((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); + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); } + else { png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; *sp = (png_byte)((v >> 8) & 0xff); *(sp + 1) = (png_byte)(v & 0xff); + v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)]; *(sp + 2) = (png_byte)((v >> 8) & 0xff); *(sp + 3) = (png_byte)(v & 0xff); + v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)]; *(sp + 4) = (png_byte)((v >> 8) & 0xff); *(sp + 5) = (png_byte)(v & 0xff); } } } + else #endif { sp = row; for (i = 0; i < row_width; i++, sp += 6) { - png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp+1)); - png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3)); - png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5)); + png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1)); - if (r == trans_color->red && g == trans_color->green && - b == trans_color->blue) + png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8) + + *(sp + 3)); + + png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8) + + *(sp + 5)); + + if (r == png_ptr->trans_color.red && + g == png_ptr->trans_color.green && + b == png_ptr->trans_color.blue) { - *sp = (png_byte)((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); + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); } } } @@ -2908,27 +3793,28 @@ png_do_background(png_row_infop row_info, png_bytep row, gamma_table != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 2, dp++) + for (i = 0; i < row_width; i++, sp += 2) { png_uint_16 a = *(sp + 1); if (a == 0xff) - { - *dp = gamma_table[*sp]; - } + *sp = gamma_table[*sp]; + else if (a == 0) { /* Background is already in screen gamma */ - *dp = (png_byte)background->gray; + *sp = (png_byte)png_ptr->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]; + png_composite(w, v, a, png_ptr->background_1.gray); + if (!optimize) + w = gamma_from_1[w]; + *sp = w; } } } @@ -2936,27 +3822,15 @@ png_do_background(png_row_infop row_info, png_bytep row, #endif { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 2, dp++) + for (i = 0; i < row_width; i++, sp += 2) { 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 + if (a == 0) + *sp = (png_byte)png_ptr->background.gray; + + else if (a < 0xff) + png_composite(*sp, *sp, a, png_ptr->background_1.gray); } } } @@ -2967,75 +3841,66 @@ png_do_background(png_row_infop row_info, png_bytep row, gamma_16_to_1 != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 4, dp += 2) + for (i = 0; i < row_width; i++, sp += 4) { - png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3)); + 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); + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 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); + *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->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); + png_composite_16(v, g, a, png_ptr->background_1.gray); + if (optimize) + w = v; + else + w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8]; + *sp = (png_byte)((w >> 8) & 0xff); + *(sp + 1) = (png_byte)(w & 0xff); } -#endif } } else #endif { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 4, dp += 2) + for (i = 0; i < row_width; i++, sp += 4) { - png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3)); - if (a == (png_uint_16)0xffff) - { - png_memcpy(dp, sp, 2); - } -#ifdef PNG_READ_GAMMA_SUPPORTED - else if (a == 0) -#else - else -#endif + png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8) + + *(sp + 3)); + + if (a == 0) { - *dp = (png_byte)((background->gray >> 8) & 0xff); - *(dp + 1) = (png_byte)(background->gray & 0xff); + *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); } -#ifdef PNG_READ_GAMMA_SUPPORTED - else + + else if (a < 0xffff) { 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); + png_composite_16(v, g, a, png_ptr->background_1.gray); + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); } -#endif } } } @@ -3051,37 +3916,43 @@ png_do_background(png_row_infop row_info, png_bytep row, gamma_table != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 4, dp += 3) + for (i = 0; i < row_width; i++, sp += 4) { png_byte a = *(sp + 3); if (a == 0xff) { - *dp = gamma_table[*sp]; - *(dp + 1) = gamma_table[*(sp + 1)]; - *(dp + 2) = gamma_table[*(sp + 2)]; + *sp = gamma_table[*sp]; + *(sp + 1) = gamma_table[*(sp + 1)]; + *(sp + 2) = gamma_table[*(sp + 2)]; } + else if (a == 0) { /* Background is already in screen gamma */ - *dp = (png_byte)background->red; - *(dp + 1) = (png_byte)background->green; - *(dp + 2) = (png_byte)background->blue; + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; } + else { png_byte v, w; v = gamma_to_1[*sp]; - png_composite(w, v, a, background_1->red); - *dp = gamma_from_1[w]; + png_composite(w, v, a, png_ptr->background_1.red); + if (!optimize) w = gamma_from_1[w]; + *sp = w; + v = gamma_to_1[*(sp + 1)]; - png_composite(w, v, a, background_1->green); - *(dp + 1) = gamma_from_1[w]; + png_composite(w, v, a, png_ptr->background_1.green); + if (!optimize) w = gamma_from_1[w]; + *(sp + 1) = w; + v = gamma_to_1[*(sp + 2)]; - png_composite(w, v, a, background_1->blue); - *(dp + 2) = gamma_from_1[w]; + png_composite(w, v, a, png_ptr->background_1.blue); + if (!optimize) w = gamma_from_1[w]; + *(sp + 2) = w; } } } @@ -3089,30 +3960,26 @@ png_do_background(png_row_infop row_info, png_bytep row, #endif { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 4, dp += 3) + for (i = 0; i < row_width; i++, sp += 4) { png_byte a = *(sp + 3); - if (a == 0xff) - { - *dp = *sp; - *(dp + 1) = *(sp + 1); - *(dp + 2) = *(sp + 2); - } - else if (a == 0) + if (a == 0) { - *dp = (png_byte)background->red; - *(dp + 1) = (png_byte)background->green; - *(dp + 2) = (png_byte)background->blue; + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; } - else + + else if (a < 0xff) { - 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); + png_composite(*sp, *sp, a, png_ptr->background.red); + + png_composite(*(sp + 1), *(sp + 1), a, + png_ptr->background.green); + + png_composite(*(sp + 2), *(sp + 2), a, + png_ptr->background.blue); } } } @@ -3124,80 +3991,89 @@ png_do_background(png_row_infop row_info, png_bytep row, gamma_16_to_1 != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 8, dp += 6) + for (i = 0; i < row_width; i++, sp += 8) { png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6)) << 8) + (png_uint_16)(*(sp + 7))); + if (a == (png_uint_16)0xffff) { png_uint_16 v; v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; - *dp = (png_byte)((v >> 8) & 0xff); - *(dp + 1) = (png_byte)(v & 0xff); + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 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); + *(sp + 2) = (png_byte)((v >> 8) & 0xff); + *(sp + 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); + *(sp + 4) = (png_byte)((v >> 8) & 0xff); + *(sp + 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); + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); } + else { - png_uint_16 v, w, x; + png_uint_16 v, w; 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); + png_composite_16(w, v, a, png_ptr->background_1.red); + if (!optimize) + w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8]; + *sp = (png_byte)((w >> 8) & 0xff); + *(sp + 1) = (png_byte)(w & 0xff); + v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)]; - png_composite_16(w, v, a, 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); + png_composite_16(w, v, a, png_ptr->background_1.green); + if (!optimize) + w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8]; + + *(sp + 2) = (png_byte)((w >> 8) & 0xff); + *(sp + 3) = (png_byte)(w & 0xff); + v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)]; - png_composite_16(w, v, a, 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); + png_composite_16(w, v, a, png_ptr->background_1.blue); + if (!optimize) + w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8]; + + *(sp + 4) = (png_byte)((w >> 8) & 0xff); + *(sp + 5) = (png_byte)(w & 0xff); } } } + else #endif { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 8, dp += 6) + for (i = 0; i < row_width; i++, sp += 8) { png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6)) - << 8) + (png_uint_16)(*(sp + 7))); - if (a == (png_uint_16)0xffff) - { - png_memcpy(dp, sp, 6); - } - else if (a == 0) + << 8) + (png_uint_16)(*(sp + 7))); + + 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); + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); } - else + + else if (a < 0xffff) { png_uint_16 v; @@ -3207,30 +4083,26 @@ png_do_background(png_row_infop row_info, png_bytep row, 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); + png_composite_16(v, r, a, png_ptr->background.red); + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + + png_composite_16(v, g, a, png_ptr->background.green); + *(sp + 2) = (png_byte)((v >> 8) & 0xff); + *(sp + 3) = (png_byte)(v & 0xff); + + png_composite_16(v, b, a, png_ptr->background.blue); + *(sp + 4) = (png_byte)((v >> 8) & 0xff); + *(sp + 5) = (png_byte)(v & 0xff); } } } } break; } - } - 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); + default: + break; } } } @@ -3244,19 +4116,20 @@ png_do_background(png_row_infop row_info, png_bytep row, * 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_do_gamma(png_row_infop row_info, png_bytep row, png_structp png_ptr) { + png_const_bytep gamma_table = png_ptr->gamma_table; + png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table; + int gamma_shift = png_ptr->gamma_shift; + png_bytep sp; png_uint_32 i; png_uint_32 row_width=row_info->width; png_debug(1, "in png_do_gamma"); - if ( - ((row_info->bit_depth <= 8 && gamma_table != NULL) || - (row_info->bit_depth == 16 && gamma_16_table != NULL))) + if (((row_info->bit_depth <= 8 && gamma_table != NULL) || + (row_info->bit_depth == 16 && gamma_16_table != NULL))) { switch (row_info->color_type) { @@ -3275,6 +4148,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, sp++; } } + else /* if (row_info->bit_depth == 16) */ { sp = row; @@ -3286,10 +4160,12 @@ png_do_gamma(png_row_infop row_info, png_bytep row, *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); @@ -3308,13 +4184,17 @@ png_do_gamma(png_row_infop row_info, png_bytep row, { *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; @@ -3324,10 +4204,12 @@ png_do_gamma(png_row_infop row_info, png_bytep row, *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); @@ -3348,6 +4230,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, sp += 2; } } + else /* if (row_info->bit_depth == 16) */ { sp = row; @@ -3375,10 +4258,10 @@ png_do_gamma(png_row_infop row_info, png_bytep row, 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) )); + ((((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++; } } @@ -3392,7 +4275,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, int lsb = *sp & 0x0f; *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0) - | (((int)gamma_table[(lsb << 4) | lsb]) >> 4)); + | (((int)gamma_table[(lsb << 4) | lsb]) >> 4)); sp++; } } @@ -3420,18 +4303,88 @@ png_do_gamma(png_row_infop row_info, png_bytep row, } break; } + + default: + break; } } } #endif +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED +/* Encode the alpha channel to the output gamma (the input channel is always + * linear.) Called only with color types that have an alpha channel. Needs the + * from_1 tables. + */ +void /* PRIVATE */ +png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structp png_ptr) +{ + png_uint_32 row_width = row_info->width; + + png_debug(1, "in png_do_encode_alpha"); + + if (row_info->color_type & PNG_COLOR_MASK_ALPHA) + { + if (row_info->bit_depth == 8) + { + PNG_CONST png_bytep table = png_ptr->gamma_from_1; + + if (table != NULL) + { + PNG_CONST int step = + (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2; + + /* The alpha channel is the last component: */ + row += step - 1; + + for (; row_width > 0; --row_width, row += step) + *row = table[*row]; + + return; + } + } + + else if (row_info->bit_depth == 16) + { + PNG_CONST png_uint_16pp table = png_ptr->gamma_16_from_1; + PNG_CONST int gamma_shift = png_ptr->gamma_shift; + + if (table != NULL) + { + PNG_CONST int step = + (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4; + + /* The alpha channel is the last component: */ + row += step - 2; + + for (; row_width > 0; --row_width, row += step) + { + png_uint_16 v; + + v = table[*(row + 1) >> gamma_shift][*row]; + *row = (png_byte)((v >> 8) & 0xff); + *(row + 1) = (png_byte)(v & 0xff); + } + + return; + } + } + } + + /* Only get to here if called with a weird row_info; no harm has been done, + * so just issue a warning. + */ + png_warning(png_ptr, "png_do_encode_alpha: unexpected call"); +} +#endif + #ifdef PNG_READ_EXPAND_SUPPORTED /* Expands a palette row to an RGB or RGBA row depending * upon whether you supply trans and num_trans. */ void /* PRIVATE */ png_do_expand_palette(png_row_infop row_info, png_bytep row, - png_colorp palette, png_bytep trans_alpha, int num_trans) + png_const_colorp palette, png_const_bytep trans_alpha, int num_trans) { int shift, value; png_bytep sp, dp; @@ -3440,8 +4393,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, png_debug(1, "in png_do_expand_palette"); - if ( - row_info->color_type == PNG_COLOR_TYPE_PALETTE) + if (row_info->color_type == PNG_COLOR_TYPE_PALETTE) { if (row_info->bit_depth < 8) { @@ -3456,13 +4408,16 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, { if ((*sp >> shift) & 0x01) *dp = 1; + else *dp = 0; + if (shift == 7) { shift = 0; sp--; } + else shift++; @@ -3485,6 +4440,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, shift = 0; sp--; } + else shift += 2; @@ -3507,6 +4463,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, shift = 0; sp--; } + else shift += 4; @@ -3514,16 +4471,19 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, } break; } + + default: + break; } row_info->bit_depth = 8; row_info->pixel_depth = 8; row_info->rowbytes = row_width; } - switch (row_info->bit_depth) + + if (row_info->bit_depth == 8) { - case 8: { - if (trans_alpha != NULL) + if (num_trans > 0) { sp = row + (png_size_t)row_width - 1; dp = row + (png_size_t)(row_width << 2) - 1; @@ -3532,8 +4492,10 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, { if ((int)(*sp) >= num_trans) *dp-- = 0xff; + else *dp-- = trans_alpha[*sp]; + *dp-- = palette[*sp].blue; *dp-- = palette[*sp].green; *dp-- = palette[*sp].red; @@ -3545,6 +4507,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, row_info->color_type = 6; row_info->channels = 4; } + else { sp = row + (png_size_t)row_width - 1; @@ -3564,7 +4527,6 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, row_info->color_type = 2; row_info->channels = 3; } - break; } } } @@ -3575,7 +4537,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, */ void /* PRIVATE */ png_do_expand(png_row_infop row_info, png_bytep row, - png_color_16p trans_value) + png_const_color_16p trans_color) { int shift, value; png_bytep sp, dp; @@ -3587,7 +4549,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, { if (row_info->color_type == PNG_COLOR_TYPE_GRAY) { - png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0); + png_uint_16 gray = (png_uint_16)(trans_color ? trans_color->gray : 0); if (row_info->bit_depth < 8) { @@ -3595,7 +4557,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, { case 1: { - gray = (png_uint_16)((gray&0x01)*0xff); + 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); @@ -3603,13 +4565,16 @@ png_do_expand(png_row_infop row_info, png_bytep row, { if ((*sp >> shift) & 0x01) *dp = 0xff; + else *dp = 0; + if (shift == 7) { shift = 0; sp--; } + else shift++; @@ -3620,7 +4585,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, case 2: { - gray = (png_uint_16)((gray&0x03)*0x55); + 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); @@ -3634,6 +4599,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, shift = 0; sp--; } + else shift += 2; @@ -3644,7 +4610,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, case 4: { - gray = (png_uint_16)((gray&0x0f)*0x11); + 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); @@ -3657,6 +4623,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, shift = 0; sp--; } + else shift = 4; @@ -3664,6 +4631,9 @@ png_do_expand(png_row_infop row_info, png_bytep row, } break; } + + default: + break; } row_info->bit_depth = 8; @@ -3671,27 +4641,30 @@ png_do_expand(png_row_infop row_info, png_bytep row, row_info->rowbytes = row_width; } - if (trans_value != NULL) + if (trans_color != NULL) { if (row_info->bit_depth == 8) { gray = gray & 0xff; sp = row + (png_size_t)row_width - 1; dp = row + (png_size_t)(row_width << 1) - 1; + for (i = 0; i < row_width; i++) { if (*sp == gray) *dp-- = 0; + else *dp-- = 0xff; + *dp-- = *sp--; } } else if (row_info->bit_depth == 16) { - png_byte gray_high = (gray >> 8) & 0xff; - png_byte gray_low = gray & 0xff; + png_byte gray_high = (png_byte)((gray >> 8) & 0xff); + png_byte gray_low = (png_byte)(gray & 0xff); sp = row + row_info->rowbytes - 1; dp = row + (row_info->rowbytes << 1) - 1; for (i = 0; i < row_width; i++) @@ -3701,11 +4674,13 @@ png_do_expand(png_row_infop row_info, png_bytep row, *dp-- = 0; *dp-- = 0; } + else { *dp-- = 0xff; *dp-- = 0xff; } + *dp-- = *sp--; *dp-- = *sp--; } @@ -3718,21 +4693,23 @@ png_do_expand(png_row_infop row_info, png_bytep row, row_width); } } - else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value) + else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color) { 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; + png_byte red = (png_byte)(trans_color->red & 0xff); + png_byte green = (png_byte)(trans_color->green & 0xff); + png_byte blue = (png_byte)(trans_color->blue & 0xff); sp = row + (png_size_t)row_info->rowbytes - 1; dp = row + (png_size_t)(row_width << 2) - 1; for (i = 0; i < row_width; i++) { if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue) *dp-- = 0; + else *dp-- = 0xff; + *dp-- = *sp--; *dp-- = *sp--; *dp-- = *sp--; @@ -3740,31 +4717,33 @@ png_do_expand(png_row_infop row_info, png_bytep row, } 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; + png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff); + png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff); + png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff); + png_byte red_low = (png_byte)(trans_color->red & 0xff); + png_byte green_low = (png_byte)(trans_color->green & 0xff); + png_byte blue_low = (png_byte)(trans_color->blue & 0xff); sp = row + row_info->rowbytes - 1; dp = row + (png_size_t)(row_width << 3) - 1; for (i = 0; i < row_width; i++) { if (*(sp - 5) == red_high && - *(sp - 4) == red_low && - *(sp - 3) == green_high && - *(sp - 2) == green_low && - *(sp - 1) == blue_high && - *(sp ) == blue_low) + *(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--; @@ -3782,20 +4761,51 @@ png_do_expand(png_row_infop row_info, png_bytep row, } #endif -#ifdef PNG_READ_DITHER_SUPPORTED +#ifdef PNG_READ_EXPAND_16_SUPPORTED +/* If the bit depth is 8 and the colour type is not a palette type expand the + * whole row to 16 bits. Has no effect otherwise. + */ void /* PRIVATE */ -png_do_dither(png_row_infop row_info, png_bytep row, - png_bytep palette_lookup, png_bytep dither_lookup) +png_do_expand_16(png_row_infop row_info, png_bytep row) +{ + if (row_info->bit_depth == 8 && + row_info->color_type != PNG_COLOR_TYPE_PALETTE) + { + /* The row have a sequence of bytes containing [0..255] and we need + * to turn it into another row containing [0..65535], to do this we + * calculate: + * + * (input / 255) * 65535 + * + * Which happens to be exactly input * 257 and this can be achieved + * simply by byte replication in place (copying backwards). + */ + png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */ + png_byte *dp = sp + row_info->rowbytes; /* destination, end + 1 */ + while (dp > sp) + dp[-2] = dp[-1] = *--sp, dp -= 2; + + row_info->rowbytes *= 2; + row_info->bit_depth = 16; + row_info->pixel_depth = (png_byte)(row_info->channels * 16); + } +} +#endif + +#ifdef PNG_READ_QUANTIZE_SUPPORTED +void /* PRIVATE */ +png_do_quantize(png_row_infop row_info, png_bytep row, + png_const_bytep palette_lookup, png_const_bytep quantize_lookup) { png_bytep sp, dp; png_uint_32 i; png_uint_32 row_width=row_info->width; - png_debug(1, "in png_do_dither"); + png_debug(1, "in png_do_quantize"); + if (row_info->bit_depth == 8) { - if (row_info->color_type == PNG_COLOR_TYPE_RGB && - palette_lookup && row_info->bit_depth == 8) + if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup) { int r, g, b, p; sp = row; @@ -3813,24 +4823,26 @@ png_do_dither(png_row_infop row_info, png_bytep row, * (((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)); + 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) + palette_lookup != NULL) { int r, g, b, p; sp = row; @@ -3842,293 +4854,38 @@ png_do_dither(png_row_infop row_info, png_bytep row, 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)); + 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 && - dither_lookup && row_info->bit_depth == 8) + quantize_lookup) { sp = row; + for (i = 0; i < row_width; i++, sp++) { - *sp = dither_lookup[*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 +#endif /* PNG_READ_QUANTIZE_SUPPORTED */ +#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ #ifdef PNG_MNG_FEATURES_SUPPORTED /* Undoes intrapixel differencing */ @@ -4142,6 +4899,7 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) { int bytes_per_pixel; png_uint_32 row_width = row_info->width; + if (row_info->bit_depth == 8) { png_bytep rp; @@ -4158,8 +4916,8 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) 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); + *(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) @@ -4183,10 +4941,10 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) 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); + *(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); } } } |