X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/5b02c8a11f0e0d284eff32cfde1fcd2a4b2e659d..e264485aac3699e8bd876c3feeee2eb48c61a81f:/src/png/pngrtran.c diff --git a/src/png/pngrtran.c b/src/png/pngrtran.c index 0e4ca2bb6b..1079595f0a 100644 --- a/src/png/pngrtran.c +++ b/src/png/pngrtran.c @@ -1,67 +1,86 @@ /* pngrtran.c - transforms the data in a row for PNG readers * - * libpng version 1.2.6 - August 15, 2004 - * For conditions of distribution and use, see copyright notice in png.h - * Copyright (c) 1998-2004 Glenn Randers-Pehrson + * Last changed in libpng 1.5.7 [December 15, 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.) * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * * This file contains functions optionally called by an application * in order to tell libpng how to handle data when reading a PNG. * Transformations that are used in both reading and writing are * in pngtrans.c. */ -#define PNG_INTERNAL -#include "png.h" +#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\n"); + png_debug(1, "in png_set_crc_action"); + + if (png_ptr == NULL) + return; + /* Tell libpng how we react to CRC errors in critical chunks */ switch (crit_action) { - case PNG_CRC_NO_CHANGE: /* leave setting as is */ + case PNG_CRC_NO_CHANGE: /* Leave setting as is */ break; - case PNG_CRC_WARN_USE: /* warn/use data */ + + case PNG_CRC_WARN_USE: /* Warn/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE; break; - case PNG_CRC_QUIET_USE: /* quiet/use data */ + + case PNG_CRC_QUIET_USE: /* Quiet/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE | PNG_FLAG_CRC_CRITICAL_IGNORE; break; - case PNG_CRC_WARN_DISCARD: /* not a valid action for critical data */ - png_warning(png_ptr, "Can't discard critical data on CRC error."); - case PNG_CRC_ERROR_QUIT: /* error/quit */ + + case PNG_CRC_WARN_DISCARD: /* Not a valid action for critical data */ + png_warning(png_ptr, + "Can't discard critical data on CRC error"); + case PNG_CRC_ERROR_QUIT: /* Error/quit */ + case PNG_CRC_DEFAULT: default: png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; break; } + /* Tell libpng how we react to CRC errors in ancillary chunks */ switch (ancil_action) { - case PNG_CRC_NO_CHANGE: /* leave setting as is */ + case PNG_CRC_NO_CHANGE: /* Leave setting as is */ break; - case PNG_CRC_WARN_USE: /* warn/use data */ + + case PNG_CRC_WARN_USE: /* Warn/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE; break; - case PNG_CRC_QUIET_USE: /* quiet/use data */ + + case PNG_CRC_QUIET_USE: /* Quiet/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN; break; - case PNG_CRC_ERROR_QUIT: /* error/quit */ + + case PNG_CRC_ERROR_QUIT: /* Error/quit */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN; break; - case PNG_CRC_WARN_DISCARD: /* warn/discard data */ + + case PNG_CRC_WARN_DISCARD: /* Warn/discard data */ + case PNG_CRC_DEFAULT: default: png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; @@ -69,67 +88,283 @@ 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) -/* 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) +#ifdef PNG_READ_BACKGROUND_SUPPORTED +/* Handle alpha and tRNS via a background color */ +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\n"); + 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; +} - /* Note: if need_expand is set and color_type is either RGB or RGB_ALPHA - * (in which case need_expand is superfluous anyway), the background color - * might actually be gray yet not be flagged as such. This is not a problem - * for the current code, which uses PNG_BACKGROUND_IS_GRAY only to - * decide when to do the png_do_gray_to_rgb() transformation. - */ - if ((need_expand && !(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) || - (!need_expand && background_color->red == background_color->green && - background_color->red == background_color->blue)) - png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; +# 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 -#if defined(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) { - png_debug(1, "in png_set_strip_16\n"); + png_debug(1, "in png_set_strip_16"); + + if (png_ptr == NULL) + return; + png_ptr->transformations |= PNG_16_TO_8; } #endif -#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED) +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED void PNGAPI png_set_strip_alpha(png_structp png_ptr) { - png_debug(1, "in png_set_strip_alpha\n"); + png_debug(1, "in png_set_strip_alpha"); + + if (png_ptr == NULL) + return; + png_ptr->transformations |= PNG_STRIP_ALPHA; } #endif -#if defined(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. */ @@ -143,21 +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\n"); - png_ptr->transformations |= PNG_DITHER; + png_debug(1, "in png_set_quantize"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= PNG_QUANTIZE; - if (!full_dither) + 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) @@ -165,61 +404,66 @@ png_set_dither(png_structp png_ptr, png_colorp palette, if (histogram != NULL) { /* This is easy enough, just throw out the least used colors. - Perhaps not the best solution, but good enough. */ + * Perhaps not the best solution, but good enough. + */ int i; - /* initialize an array to sort colors */ - png_ptr->dither_sort = (png_bytep)png_malloc(png_ptr, - (png_uint_32)(num_palette * png_sizeof (png_byte))); + /* Initialize an array to sort colors */ + png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr, + (png_uint_32)(num_palette * png_sizeof(png_byte))); - /* initialize the 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 - out enough colors. Note that we don't care about - sorting all the colors, just finding which are - least used. */ + * bubble sort, and running it until we have sorted + * out enough colors. Note that we don't care about + * sorting all the colors, just finding which are + * least used. + */ for (i = num_palette - 1; i >= maximum_colors; i--) { - int done; /* to stop early if the list is pre-sorted */ + int done; /* To stop early if the list is pre-sorted */ int j; done = 1; for (j = 0; j < i; j++) { - if (histogram[png_ptr->dither_sort[j]] - < histogram[png_ptr->dither_sort[j + 1]]) + 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) + /* Swap the palette around, and set up a table, if necessary */ + if (full_quantize) { int j = num_palette; - /* put all the useful colors within the max, but don't - move the others */ + /* Put all the useful colors within the max, but don't + * move the others. + */ for (i = 0; i < maximum_colors; i++) { - if ((int)png_ptr->dither_sort[i] >= maximum_colors) + 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]; } } @@ -228,37 +472,38 @@ png_set_dither(png_structp png_ptr, png_colorp palette, { int j = num_palette; - /* move all the used colors inside the max limit, and - develop a translation table */ + /* Move all the used colors inside the max limit, and + * develop a translation table. + */ for (i = 0; i < maximum_colors; i++) { - /* only move the colors we need to */ - if ((int)png_ptr->dither_sort[i] >= maximum_colors) + /* Only move the colors we need to */ + if ((int)png_ptr->quantize_sort[i] >= maximum_colors) { png_color tmp_color; do j--; - while ((int)png_ptr->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; + /* Indicate where the color went */ + png_ptr->quantize_index[j] = (png_byte)i; + png_ptr->quantize_index[i] = (png_byte)j; } } - /* find closest color for those colors we are not using */ + /* 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]; + /* Find the closest color to one we threw out */ + d_index = png_ptr->quantize_index[i]; min_d = PNG_COLOR_DIST(palette[d_index], palette[0]); for (k = 1, min_k = 0; k < maximum_colors; k++) { @@ -272,61 +517,58 @@ png_set_dither(png_structp png_ptr, png_colorp palette, min_k = k; } } - /* point to closest color */ - png_ptr->dither_index[i] = (png_byte)min_k; + /* Point to closest color */ + 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 { /* This is much harder to do simply (and quickly). Perhaps - we need to go through a median cut routine, but those - don't always behave themselves with only a few colors - as input. So we will just find the closest two colors, - and throw out one of them (chosen somewhat randomly). - [We don't understand this at all, so if someone wants to - work on improving it, be our guest - AED, GRP] - */ + * we need to go through a median cut routine, but those + * don't always behave themselves with only a few colors + * as input. So we will just find the closest two colors, + * and throw out one of them (chosen somewhat randomly). + * [We don't understand this at all, so if someone wants to + * work on improving it, be our guest - AED, GRP] + */ int i; int max_d; int num_new_palette; png_dsortp t; png_dsortpp hash; - t=NULL; + t = NULL; - /* initialize palette index arrays */ + /* 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 */ + /* Initialize the sort array */ for (i = 0; i < num_palette; i++) { png_ptr->index_to_palette[i] = (png_byte)i; png_ptr->palette_to_index[i] = (png_byte)i; } - hash = (png_dsortpp)png_malloc(png_ptr, (png_uint_32)(769 * - png_sizeof (png_dsortp))); - for (i = 0; i < 769; i++) - hash[i] = NULL; -/* png_memset(hash, 0, 769 * png_sizeof (png_dsortp)); */ + hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 * + png_sizeof(png_dsortp))); num_new_palette = num_palette; - /* initial wild guess at how far apart the farthest pixel - pair we will be eliminating will be. Larger - numbers mean more areas will be allocated, Smaller - numbers run the risk of not saving enough data, and - having to do this all over again. - - I have not done extensive checking on this number. - */ + /* Initial wild guess at how far apart the farthest pixel + * pair we will be eliminating will be. Larger + * numbers mean more areas will be allocated, Smaller + * numbers run the risk of not saving enough data, and + * having to do this all over again. + * + * I have not done extensive checking on this number. + */ max_d = 96; while (num_new_palette > maximum_colors) @@ -346,8 +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; @@ -368,9 +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; @@ -387,31 +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; @@ -440,8 +689,8 @@ png_set_dither(png_structp png_ptr, png_colorp palette, png_free(png_ptr, hash); png_free(png_ptr, png_ptr->palette_to_index); png_free(png_ptr, png_ptr->index_to_palette); - png_ptr->palette_to_index=NULL; - png_ptr->index_to_palette=NULL; + png_ptr->palette_to_index = NULL; + png_ptr->index_to_palette = NULL; } num_palette = maximum_colors; } @@ -451,40 +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_malloc(png_ptr, - (png_uint_32)(num_entries * png_sizeof (png_byte))); - - png_memset(png_ptr->palette_lookup, 0, num_entries * - png_sizeof (png_byte)); + 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++) { @@ -492,7 +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++) { @@ -515,32 +762,59 @@ png_set_dither(png_structp png_ptr, png_colorp palette, png_free(png_ptr, distance); } } +#endif /* PNG_READ_QUANTIZE_SUPPORTED */ + +#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_fixed"); + + if (png_ptr == NULL) + return; + + /* New in libpng-1.5.4 - reserve particular negative values as flags. */ + scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/); + file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/); + +#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 -#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. - */ + /* 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_debug(1, "in png_set_gamma\n"); - 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; + png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma), + convert_gamma_value(png_ptr, file_gamma)); } -#endif +# endif /* FLOATING_POINT_SUPPORTED */ +#endif /* READ_GAMMA */ -#if defined(PNG_READ_EXPAND_SUPPORTED) +#ifdef PNG_READ_EXPAND_SUPPORTED /* Expand paletted images to RGB, expand grayscale images of * less than 8-bit depth to 8-bit depth, and expand tRNS chunks * to alpha channels. @@ -548,8 +822,13 @@ png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma) void PNGAPI png_set_expand(png_structp png_ptr) { - png_debug(1, "in png_set_expand\n"); - png_ptr->transformations |= PNG_EXPAND; + png_debug(1, "in png_set_expand"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } /* GRR 19990627: the following three functions currently are identical @@ -564,238 +843,719 @@ png_set_expand(png_structp png_ptr) * * More to the point, these functions make it obvious what libpng will be * doing, whereas "expand" can (and does) mean any number of things. + * + * GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified + * to expand only the sample depth but not to expand the tRNS to alpha + * and its name was changed to png_set_expand_gray_1_2_4_to_8(). */ /* Expand paletted images to RGB. */ void PNGAPI png_set_palette_to_rgb(png_structp png_ptr) { - png_debug(1, "in png_set_expand\n"); - png_ptr->transformations |= PNG_EXPAND; + png_debug(1, "in png_set_palette_to_rgb"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } /* Expand grayscale images of less than 8-bit depth to 8 bits. */ void PNGAPI -png_set_gray_1_2_4_to_8(png_structp png_ptr) +png_set_expand_gray_1_2_4_to_8(png_structp png_ptr) { - png_debug(1, "in png_set_expand\n"); + png_debug(1, "in png_set_expand_gray_1_2_4_to_8"); + + if (png_ptr == NULL) + return; + png_ptr->transformations |= PNG_EXPAND; + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } + + /* Expand tRNS chunks to alpha channels. */ void PNGAPI png_set_tRNS_to_alpha(png_structp png_ptr) { - png_debug(1, "in png_set_expand\n"); - png_ptr->transformations |= PNG_EXPAND; + png_debug(1, "in png_set_tRNS_to_alpha"); + + png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); + png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } #endif /* defined(PNG_READ_EXPAND_SUPPORTED) */ -#if defined(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\n"); - png_ptr->transformations |= PNG_GRAY_TO_RGB; + png_debug(1, "in png_set_expand_16"); + + if (png_ptr == NULL) + return; + + 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 -#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) -#if defined(PNG_FLOATING_POINT_SUPPORTED) -/* Convert a RGB image to a grayscale of the same width. This allows us, - * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image. - */ - +#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); - 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\n"); + png_debug(1, "in png_set_rgb_to_gray"); + + if (png_ptr == NULL) + return; + switch(error_action) { - case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY; - break; - case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN; - break; - case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR; + case PNG_ERROR_ACTION_NONE: + png_ptr->transformations |= PNG_RGB_TO_GRAY; + break; + + case PNG_ERROR_ACTION_WARN: + png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN; + break; + + case PNG_ERROR_ACTION_ERROR: + png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR; + break; + + default: + png_error(png_ptr, "invalid error action to rgb_to_gray"); + break; } if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) -#if defined(PNG_READ_EXPAND_SUPPORTED) +#ifdef PNG_READ_EXPAND_SUPPORTED png_ptr->transformations |= PNG_EXPAND; #else { - png_warning(png_ptr, "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED."); + 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) { - red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L); - green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L); + png_uint_16 red_int, green_int; + + /* NOTE: this calculation does not round, but this behavior is retained + * for consistency, the inaccuracy is very small. The code here always + * overwrites the coefficients, regardless of whether they have been + * defaulted or set already. + */ + red_int = (png_uint_16)(((png_uint_32)red*32768)/100000); + green_int = (png_uint_16)(((png_uint_32)green*32768)/100000); + + png_ptr->rgb_to_gray_red_coeff = red_int; + png_ptr->rgb_to_gray_green_coeff = green_int; + png_ptr->rgb_to_gray_coefficients_set = 1; } + else { - 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 historical + * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See + * png_do_rgb_to_gray for more discussion of the values. In this case + * the coefficients are not marked as 'set' and are not overwritten if + * something has already provided a default. + */ + if (png_ptr->rgb_to_gray_red_coeff == 0 && + png_ptr->rgb_to_gray_green_coeff == 0) + { + png_ptr->rgb_to_gray_red_coeff = 6968; + png_ptr->rgb_to_gray_green_coeff = 23434; + /* png_ptr->rgb_to_gray_blue_coeff = 2366; */ + } } - 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) || \ - defined(PNG_LEGACY_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\n"); -#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) + png_debug(1, "in png_set_read_user_transform_fn"); + + if (png_ptr == NULL) + return; + +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED png_ptr->transformations |= PNG_USER_TRANSFORM; png_ptr->read_user_transform_fn = read_user_transform_fn; #endif -#ifdef PNG_LEGACY_SUPPORTED - if(read_user_transform_fn) - png_warning(png_ptr, - "This version of libpng does not support user transforms"); +} #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\n"); -#if defined(PNG_USELESS_TESTS_SUPPORTED) - if(png_ptr != NULL) -#endif - { -#if defined(PNG_READ_BACKGROUND_SUPPORTED) || defined(PNG_READ_SHIFT_SUPPORTED) \ - || defined(PNG_READ_GAMMA_SUPPORTED) - int color_type = png_ptr->color_type; -#endif + /* Called to handle the (input) palette case. In png_do_read_transformations + * the first step is to expand the palette if requested, so this code must + * take care to only make changes that are invariant with respect to the + * palette expansion, or only do them if there is no expansion. + * + * STRIP_ALPHA has already been handled in the caller (by setting num_trans + * to 0.) + */ + int input_has_alpha = 0; + int input_has_transparency = 0; + + if (png_ptr->num_trans > 0) + { + int i; + + /* Ignore if all the entries are opaque (unlikely!) */ + for (i=0; inum_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. + */ + + /* 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)) { - if (!(color_type & PNG_COLOR_MASK_COLOR)) /* i.e., GRAY or GRAY_ALPHA */ { - /* expand background chunk. */ + png_ptr->background.red = + png_ptr->palette[png_ptr->background.index].red; + png_ptr->background.green = + png_ptr->palette[png_ptr->background.index].green; + png_ptr->background.blue = + png_ptr->palette[png_ptr->background.index].blue; + +#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; itrans_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) + { + /* 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); + } + +#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->color_type & PNG_COLOR_MASK_COLOR)) + /* i.e., GRAY or GRAY_ALPHA */ + { + { + /* Expand background and tRNS chunks */ + int gray = png_ptr->background.gray; + int trans_gray = png_ptr->trans_color.gray; + switch (png_ptr->bit_depth) { case 1: - png_ptr->background.gray *= (png_uint_16)0xff; - png_ptr->background.red = png_ptr->background.green - = png_ptr->background.blue = png_ptr->background.gray; + gray *= 0xff; + trans_gray *= 0xff; 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; + gray *= 0x55; + trans_gray *= 0x55; 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; + gray *= 0x11; + trans_gray *= 0x11; break; + + default: + case 8: + /* Already 8 bits, fall through */ + case 16: - png_ptr->background.red = png_ptr->background.green - = png_ptr->background.blue = png_ptr->background.gray; + /* Already a full 16 bits */ break; } + + png_ptr->background.red = png_ptr->background.green = + png_ptr->background.blue = (png_uint_16)gray; + + if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) + { + png_ptr->trans_color.red = png_ptr->trans_color.green = + png_ptr->trans_color.blue = (png_uint_16)trans_gray; + } } - 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); -#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) - if (png_ptr->transformations & PNG_INVERT_ALPHA) - { -#if defined(PNG_READ_EXPAND_SUPPORTED) - if (!(png_ptr->transformations & PNG_EXPAND)) + 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; itrans[i] = (png_byte)(255 - png_ptr->trans[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 grayscale 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) */ + + /* 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 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) + else + png_init_rgb_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)) +#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; inum_trans; i++) - { - if (png_ptr->trans[i] != 0 && png_ptr->trans[i] != 0xff) - k=1; /* partial transparency is present */ - } - if (k == 0) - png_ptr->transformations &= (~PNG_GAMMA); + /* 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 */ - if (png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) +#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ + (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \ + defined(PNG_READ_STRIP_16_TO_8_SUPPORTED)) + if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) && + (png_ptr->transformations & PNG_COMPOSE) && + !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + png_ptr->bit_depth == 16) { - png_build_gamma_table(png_ptr); -#if defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->transformations & PNG_BACKGROUND) + /* On the other hand, if a 16-bit file is to be reduced to 8-bits per + * component this will also happen after PNG_COMPOSE and so the background + * color must be pre-expanded here. + * + * TODO: fix this too. + */ + png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257); + png_ptr->background.green = + (png_uint_16)(png_ptr->background.green * 257); + png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257); + png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257); + } +#endif + + /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the + * background support (see the comments in scripts/pnglibconf.dfa), this + * allows pre-multiplication of the alpha channel to be implemented as + * compositing on black. This is probably sub-optimal and has been done in + * 1.5.4 betas simply to enable external critique and testing (i.e. to + * implement the new API quickly, without lots of internal changes.) + */ + +#ifdef PNG_READ_GAMMA_SUPPORTED +# ifdef PNG_READ_BACKGROUND_SUPPORTED + /* Includes ALPHA_MODE */ + png_ptr->background_1 = png_ptr->background; +# endif + + /* This needs to change - in the palette image case a whole set of tables are + * built when it would be quicker to just calculate the correct value for + * each palette entry directly. Also, the test is too tricky - why check + * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that + * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the + * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction + * the gamma tables will not be built even if composition is required on a + * gamma encoded value. + * + * In 1.5.4 this is addressed below by an additional check on the individual + * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the + * tables. + */ + if ((png_ptr->transformations & PNG_GAMMA) + || ((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_COMPOSE) { - if (color_type == PNG_COLOR_TYPE_PALETTE) + /* Issue a warning about this combination: because RGB_TO_GRAY is + * optimized to do the gamma transform if present yet do_background has + * to do the same thing if both options are set a + * double-gamma-correction happens. This is true in all versions of + * libpng to date. + */ + if (png_ptr->transformations & PNG_RGB_TO_GRAY) + png_warning(png_ptr, + "libpng does not support gamma+background+rgb_to_gray"); + + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { - /* could skip if no transparency and - */ + /* 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]; @@ -806,73 +1566,90 @@ 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, gs) * 255.0 + .5); - back.green = (png_byte)(pow( - (double)png_ptr->background.green/255, gs) * 255.0 + .5); - back.blue = (png_byte)(pow( - (double)png_ptr->background.blue/255, gs) * 255.0 + .5); + back_1.red = png_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, g) * 255.0 + .5); - back_1.green = (png_byte)(pow( - (double)png_ptr->background.green/255, g) * 255.0 + .5); - back_1.blue = (png_byte)(pow( - (double)png_ptr->background.blue/255, g) * 255.0 + .5); + 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[i] != 0xff) + if (i < (int)png_ptr->num_trans && + png_ptr->trans_alpha[i] != 0xff) { - if (png_ptr->trans[i] == 0) + if (png_ptr->trans_alpha[i] == 0) { palette[i] = back; } - else /* if (png_ptr->trans[i] != 0xff) */ + else /* if (png_ptr->trans_alpha[i] != 0xff) */ { png_byte v, w; v = png_ptr->gamma_to_1[palette[i].red]; - png_composite(w, v, png_ptr->trans[i], back_1.red); + png_composite(w, v, png_ptr->trans_alpha[i], back_1.red); palette[i].red = png_ptr->gamma_from_1[w]; v = png_ptr->gamma_to_1[palette[i].green]; - png_composite(w, v, png_ptr->trans[i], back_1.green); + png_composite(w, v, png_ptr->trans_alpha[i], back_1.green); palette[i].green = png_ptr->gamma_from_1[w]; v = png_ptr->gamma_to_1[palette[i].blue]; - png_composite(w, v, png_ptr->trans[i], back_1.blue); + png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue); palette[i].blue = png_ptr->gamma_from_1[w]; } } @@ -883,90 +1660,139 @@ png_init_read_transformations(png_structp png_ptr) palette[i].blue = png_ptr->gamma_table[palette[i].blue]; } } - } + + /* Prevent the transformations being done again. + * + * NOTE: this is highly dubious; it removes the transformations in + * place. This seems inconsistent with the general treatment of the + * transformations elsewhere. + */ + png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA); + } /* color_type == PNG_COLOR_TYPE_PALETTE */ + /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */ - else - /* color_type != PNG_COLOR_TYPE_PALETTE */ + 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; + int gs_sig, g_sig; + png_fixed_point g = PNG_FP_1; /* Correction to linear */ + png_fixed_point gs = PNG_FP_1; /* Correction to screen */ switch (png_ptr->background_gamma_type) { case PNG_BACKGROUND_GAMMA_SCREEN: - g = (png_ptr->screen_gamma); - gs = 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); + g_sig = png_gamma_significant(g); + gs_sig = png_gamma_significant(gs); + + if (g_sig) + png_ptr->background_1.gray = png_gamma_correct(png_ptr, + png_ptr->background.gray, g); + + if (gs_sig) + 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); + if (g_sig) + { + png_ptr->background_1.red = png_gamma_correct(png_ptr, + png_ptr->background.red, g); + + png_ptr->background_1.green = png_gamma_correct(png_ptr, + png_ptr->background.green, g); + + png_ptr->background_1.blue = png_gamma_correct(png_ptr, + png_ptr->background.blue, g); + } + + if (gs_sig) + { + 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; } - } - } + + /* The background is now in screen gamma: */ + png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN; + } /* color_type != PNG_COLOR_TYPE_PALETTE */ + }/* png_ptr->transformations & PNG_BACKGROUND */ + else - /* transformation does not include PNG_BACKGROUND */ + /* 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 +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + /* RGB_TO_GRAY needs to have non-gamma-corrected values! */ + && ((png_ptr->transformations & PNG_EXPAND) == 0 || + (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0) +#endif + ) { png_colorp palette = png_ptr->palette; int num_palette = png_ptr->num_palette; int i; + /*NOTE: there are other transformations that should probably be in here + * too. + */ for (i = 0; i < num_palette; i++) { palette[i].red = png_ptr->gamma_table[palette[i].red]; palette[i].green = png_ptr->gamma_table[palette[i].green]; palette[i].blue = png_ptr->gamma_table[palette[i].blue]; } - } + + /* Done the gamma correction. */ + png_ptr->transformations &= ~PNG_GAMMA; + } /* color_type == PALETTE && !PNG_BACKGROUND transformation */ } -#if defined(PNG_READ_BACKGROUND_SUPPORTED) +#ifdef PNG_READ_BACKGROUND_SUPPORTED else #endif -#endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */ -#if defined(PNG_READ_BACKGROUND_SUPPORTED) - /* No GAMMA transformation */ - if ((png_ptr->transformations & PNG_BACKGROUND) && - (color_type == PNG_COLOR_TYPE_PALETTE)) +#endif /* PNG_READ_GAMMA_SUPPORTED */ + +#ifdef PNG_READ_BACKGROUND_SUPPORTED + /* 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; @@ -979,54 +1805,68 @@ png_init_read_transformations(png_structp png_ptr) for (i = 0; i < istop; i++) { - if (png_ptr->trans[i] == 0) + if (png_ptr->trans_alpha[i] == 0) { palette[i] = back; } - else if (png_ptr->trans[i] != 0xff) + + 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[i], back.red); + png_ptr->trans_alpha[i], back.red); + png_composite(palette[i].green, palette[i].green, - png_ptr->trans[i], back.green); + png_ptr->trans_alpha[i], back.green); + png_composite(palette[i].blue, palette[i].blue, - png_ptr->trans[i], back.blue); + png_ptr->trans_alpha[i], back.blue); } } + + png_ptr->transformations &= ~PNG_COMPOSE; } #endif /* PNG_READ_BACKGROUND_SUPPORTED */ -#if defined(PNG_READ_SHIFT_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; - int sr = 8 - png_ptr->sig_bit.red; - int sg = 8 - png_ptr->sig_bit.green; - int sb = 8 - png_ptr->sig_bit.blue; - - if (sr < 0 || sr > 8) - sr = 0; - if (sg < 0 || sg > 8) - sg = 0; - if (sb < 0 || sb > 8) - sb = 0; - for (i = 0; i < istop; i++) + int i; + int istop = png_ptr->num_palette; + int shift = 8 - png_ptr->sig_bit.red; + + /* significant bits can be in the range 1 to 7 for a meaninful result, if + * the number of significant bits is 0 then no shift is done (this is an + * error condition which is silently ignored.) + */ + if (shift > 0 && shift < 8) for (i=0; ipalette[i].red >>= sr; - png_ptr->palette[i].green >>= sg; - png_ptr->palette[i].blue >>= sb; + int component = png_ptr->palette[i].red; + + component >>= shift; + png_ptr->palette[i].red = (png_byte)component; + } + + shift = 8 - png_ptr->sig_bit.green; + if (shift > 0 && shift < 8) for (i=0; ipalette[i].green; + + component >>= shift; + png_ptr->palette[i].green = (png_byte)component; + } + + shift = 8 - png_ptr->sig_bit.blue; + if (shift > 0 && shift < 8) for (i=0; ipalette[i].blue; + + component >>= shift; + png_ptr->palette[i].blue = (png_byte)component; } } #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 @@ -1036,129 +1876,195 @@ png_init_read_transformations(png_structp png_ptr) void /* PRIVATE */ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) { - png_debug(1, "in png_read_transform_info\n"); -#if defined(PNG_READ_EXPAND_SUPPORTED) + png_debug(1, "in png_read_transform_info"); + +#ifdef PNG_READ_EXPAND_SUPPORTED if (png_ptr->transformations & PNG_EXPAND) { if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { - if (png_ptr->num_trans) + /* 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; } else { if (png_ptr->num_trans) - info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; + { + if (png_ptr->transformations & PNG_EXPAND_tRNS) + info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; + } if (info_ptr->bit_depth < 8) info_ptr->bit_depth = 8; + info_ptr->num_trans = 0; } } #endif -#if defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->transformations & PNG_BACKGROUND) - { - info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA; - info_ptr->num_trans = 0; +#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 -#if defined(PNG_READ_GAMMA_SUPPORTED) - if (png_ptr->transformations & PNG_GAMMA) - { -#ifdef PNG_FLOATING_POINT_SUPPORTED - info_ptr->gamma = png_ptr->gamma; -#endif -#ifdef PNG_FIXED_POINT_SUPPORTED - info_ptr->int_gamma = png_ptr->int_gamma; +#ifdef PNG_READ_GAMMA_SUPPORTED + /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4), + * however it seems that the code in png_init_read_transformations, which has + * been called before this from png_read_update_info->png_read_start_row + * sometimes does the gamma transform and cancels the flag. + */ + info_ptr->gamma = png_ptr->gamma; #endif + + if (info_ptr->bit_depth == 16) + { +# ifdef PNG_READ_16BIT_SUPPORTED +# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_SCALE_16_TO_8) + 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 + +# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + png_ptr->transformations |= PNG_SCALE_16_TO_8; + info_ptr->bit_depth = 8; +# else + + CONFIGURATION ERROR: you must enable at least one 16 to 8 method +# endif +# endif +#endif /* !READ_16BIT_SUPPORTED */ } + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + if (png_ptr->transformations & PNG_GRAY_TO_RGB) + info_ptr->color_type = (png_byte)(info_ptr->color_type | + PNG_COLOR_MASK_COLOR); #endif -#if defined(PNG_READ_16_TO_8_SUPPORTED) - if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16)) - info_ptr->bit_depth = 8; +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + if (png_ptr->transformations & PNG_RGB_TO_GRAY) + info_ptr->color_type = (png_byte)(info_ptr->color_type & + ~PNG_COLOR_MASK_COLOR); #endif -#if defined(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)) && - png_ptr->palette_lookup && info_ptr->bit_depth == 8) + (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) && + png_ptr->palette_lookup && info_ptr->bit_depth == 8) { info_ptr->color_type = PNG_COLOR_TYPE_PALETTE; } } #endif -#if defined(PNG_READ_PACK_SUPPORTED) - if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8)) - info_ptr->bit_depth = 8; -#endif - -#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) - if (png_ptr->transformations & PNG_GRAY_TO_RGB) - info_ptr->color_type |= PNG_COLOR_MASK_COLOR; +#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 -#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) - if (png_ptr->transformations & PNG_RGB_TO_GRAY) - info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR; +#ifdef PNG_READ_PACK_SUPPORTED + if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8)) + info_ptr->bit_depth = 8; #endif if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) info_ptr->channels = 1; + else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR) info_ptr->channels = 3; + else info_ptr->channels = 1; -#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED) +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED if (png_ptr->transformations & PNG_STRIP_ALPHA) - info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA; + { + info_ptr->color_type = (png_byte)(info_ptr->color_type & + ~PNG_COLOR_MASK_ALPHA); + info_ptr->num_trans = 0; + } #endif if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA) info_ptr->channels++; -#if defined(PNG_READ_FILLER_SUPPORTED) +#ifdef PNG_READ_FILLER_SUPPORTED /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */ if ((png_ptr->transformations & PNG_FILLER) && ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) || (info_ptr->color_type == PNG_COLOR_TYPE_GRAY))) { info_ptr->channels++; -#if 0 /* if adding a true alpha channel not just filler */ - info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; -#endif + /* If adding a true alpha channel not just filler */ + if (png_ptr->transformations & PNG_ADD_ALPHA) + info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; } #endif #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \ defined(PNG_READ_USER_TRANSFORM_SUPPORTED) - if(png_ptr->transformations & PNG_USER_TRANSFORM) - { - if(info_ptr->bit_depth < png_ptr->user_transform_depth) + if (png_ptr->transformations & PNG_USER_TRANSFORM) + { + if (info_ptr->bit_depth < png_ptr->user_transform_depth) info_ptr->bit_depth = png_ptr->user_transform_depth; - if(info_ptr->channels < png_ptr->user_transform_channels) + + 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); - 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; -#if !defined(PNG_READ_EXPAND_SUPPORTED) - if(png_ptr) +#ifndef PNG_READ_EXPAND_SUPPORTED + if (png_ptr) return; #endif } @@ -1168,232 +2074,291 @@ defined(PNG_READ_USER_TRANSFORM_SUPPORTED) * decide how it fits in with the other transformations here. */ void /* PRIVATE */ -png_do_read_transformations(png_structp png_ptr) +png_do_read_transformations(png_structp png_ptr, png_row_infop row_info) { - png_debug(1, "in png_do_read_transformations\n"); -#if !defined(PNG_USELESS_TESTS_SUPPORTED) + png_debug(1, "in png_do_read_transformations"); + if (png_ptr->row_buf == NULL) { -#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE) - char msg[50]; - - sprintf(msg, "NULL row buffer for row %ld, pass %d", 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 } -#endif -#if defined(PNG_READ_EXPAND_SUPPORTED) + /* 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). + */ + png_error(png_ptr, "Uninitialized row"); + } + +#ifdef PNG_READ_EXPAND_SUPPORTED if (png_ptr->transformations & PNG_EXPAND) { - if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE) + if (row_info->color_type == PNG_COLOR_TYPE_PALETTE) { - png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1, - png_ptr->palette, png_ptr->trans, png_ptr->num_trans); + png_do_expand_palette(row_info, png_ptr->row_buf + 1, + png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans); } + else { - if (png_ptr->num_trans) - png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, - &(png_ptr->trans_values)); + if (png_ptr->num_trans && + (png_ptr->transformations & PNG_EXPAND_tRNS)) + png_do_expand(row_info, png_ptr->row_buf + 1, + &(png_ptr->trans_color)); + else - png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1, - NULL); + png_do_expand(row_info, png_ptr->row_buf + 1, + NULL); } } #endif -#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED) - if (png_ptr->transformations & PNG_STRIP_ALPHA) - png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, - PNG_FLAG_FILLER_AFTER); +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + !(png_ptr->transformations & PNG_COMPOSE) && + (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA || + row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) + png_do_strip_channel(row_info, png_ptr->row_buf + 1, + 0 /* at_start == false, because SWAP_ALPHA happens later */); #endif -#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED if (png_ptr->transformations & PNG_RGB_TO_GRAY) { int rgb_error = - png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info), png_ptr->row_buf + 1); - if(rgb_error) + png_do_rgb_to_gray(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_WARN) + 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_ERR) + + if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == + PNG_RGB_TO_GRAY_ERR) png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel"); } } #endif -/* -From Andreas Dilger e-mail to png-implement, 26 March 1998: - - In most cases, the "simple transparency" should be done prior to doing - gray-to-RGB, or you will have to test 3x as many bytes to check if a - pixel is transparent. You would also need to make sure that the - transparency information is upgraded to RGB. - - To summarize, the current flow is: - - Gray + simple transparency -> compare 1 or 2 gray bytes and composite - with background "in place" if transparent, - convert to RGB if necessary - - Gray + alpha -> composite with gray background and remove alpha bytes, - convert to RGB if necessary - - To support RGB backgrounds for gray images we need: - - Gray + simple transparency -> convert to RGB + simple transparency, compare - 3 or 6 bytes and composite with background - "in place" if transparent (3x compare/pixel - compared to doing composite with gray bkgrnd) - - Gray + alpha -> convert to RGB + alpha, composite with background and - remove alpha bytes (3x float operations/pixel - compared with composite on gray background) - - Greg's change will do this. The reason it wasn't done before is for - performance, as this increases the per-pixel operations. If we would check - in advance if the background was gray or RGB, and position the gray-to-RGB - transform appropriately, then it would save a lot of work/time. +/* From Andreas Dilger e-mail to png-implement, 26 March 1998: + * + * In most cases, the "simple transparency" should be done prior to doing + * gray-to-RGB, or you will have to test 3x as many bytes to check if a + * pixel is transparent. You would also need to make sure that the + * transparency information is upgraded to RGB. + * + * To summarize, the current flow is: + * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite + * with background "in place" if transparent, + * convert to RGB if necessary + * - Gray + alpha -> composite with gray background and remove alpha bytes, + * convert to RGB if necessary + * + * To support RGB backgrounds for gray images we need: + * - Gray + simple transparency -> convert to RGB + simple transparency, + * compare 3 or 6 bytes and composite with + * background "in place" if transparent + * (3x compare/pixel compared to doing + * composite with gray bkgrnd) + * - Gray + alpha -> convert to RGB + alpha, composite with background and + * remove alpha bytes (3x float + * operations/pixel compared with composite + * on gray background) + * + * Greg's change will do this. The reason it wasn't done before is for + * performance, as this increases the per-pixel operations. If we would check + * in advance if the background was gray or RGB, and position the gray-to-RGB + * transform appropriately, then it would save a lot of work/time. */ -#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) - /* if gray -> RGB, do so now only if background is non-gray; else do later - * for performance reasons */ +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + /* If gray -> RGB, do so now only if background is non-gray; else do later + * for performance reasons + */ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) - png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1); +#endif + +#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\ + (defined PNG_READ_ALPHA_MODE_SUPPORTED) + if (png_ptr->transformations & PNG_COMPOSE) + png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr); +#endif + +#ifdef PNG_READ_GAMMA_SUPPORTED + if ((png_ptr->transformations & PNG_GAMMA) && +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + /* Because RGB_TO_GRAY does the gamma transform. */ + !(png_ptr->transformations & PNG_RGB_TO_GRAY) && +#endif +#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\ + (defined PNG_READ_ALPHA_MODE_SUPPORTED) + /* Because PNG_COMPOSE does the gamma transform if there is something to + * do (if there is an alpha channel or transparency.) + */ + !((png_ptr->transformations & PNG_COMPOSE) && + ((png_ptr->num_trans != 0) || + (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) && #endif - -#if defined(PNG_READ_BACKGROUND_SUPPORTED) - if ((png_ptr->transformations & PNG_BACKGROUND) && - ((png_ptr->num_trans != 0 ) || - (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) - png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1, - &(png_ptr->trans_values), &(png_ptr->background) -#if defined(PNG_READ_GAMMA_SUPPORTED) - , &(png_ptr->background_1), - png_ptr->gamma_table, png_ptr->gamma_from_1, - png_ptr->gamma_to_1, png_ptr->gamma_16_table, - png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1, - png_ptr->gamma_shift + /* Because png_init_read_transformations transforms the palette, unless + * RGB_TO_GRAY will do the transform. + */ + (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)) + png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr); #endif -); + +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + (png_ptr->transformations & PNG_COMPOSE) && + (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA || + row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) + png_do_strip_channel(row_info, png_ptr->row_buf + 1, + 0 /* at_start == false, because SWAP_ALPHA happens later */); #endif -#if defined(PNG_READ_GAMMA_SUPPORTED) - if ((png_ptr->transformations & PNG_GAMMA) && -#if defined(PNG_READ_BACKGROUND_SUPPORTED) - !((png_ptr->transformations & PNG_BACKGROUND) && - ((png_ptr->num_trans != 0) || - (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) && +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED + if ((png_ptr->transformations & PNG_ENCODE_ALPHA) && + (row_info->color_type & PNG_COLOR_MASK_ALPHA)) + png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr); #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); + +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_SCALE_16_TO_8) + png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1); #endif -#if defined(PNG_READ_16_TO_8_SUPPORTED) +#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); + png_do_chop(row_info, png_ptr->row_buf + 1); #endif -#if defined(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(row_info, png_ptr->row_buf + 1, + png_ptr->palette_lookup, png_ptr->quantize_index); + + if (row_info->rowbytes == 0) + png_error(png_ptr, "png_do_quantize returned rowbytes=0"); } +#endif /* 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(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(row_info, png_ptr->row_buf + 1); #endif -#if defined(PNG_READ_INVERT_SUPPORTED) +#ifdef PNG_READ_INVERT_SUPPORTED if (png_ptr->transformations & PNG_INVERT_MONO) - png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_invert(row_info, png_ptr->row_buf + 1); #endif -#if defined(PNG_READ_SHIFT_SUPPORTED) +#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_do_unshift(row_info, png_ptr->row_buf + 1, + &(png_ptr->shift)); #endif -#if defined(PNG_READ_PACK_SUPPORTED) +#ifdef PNG_READ_PACK_SUPPORTED if (png_ptr->transformations & PNG_PACK) - png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_unpack(row_info, png_ptr->row_buf + 1); #endif -#if defined(PNG_READ_BGR_SUPPORTED) +#ifdef PNG_READ_BGR_SUPPORTED if (png_ptr->transformations & PNG_BGR) - png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_bgr(row_info, png_ptr->row_buf + 1); #endif -#if defined(PNG_READ_PACKSWAP_SUPPORTED) +#ifdef PNG_READ_PACKSWAP_SUPPORTED if (png_ptr->transformations & PNG_PACKSWAP) - png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1); -#endif - -#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) - /* if gray -> RGB, do so now only if we did not do so above */ - if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && - (png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) - png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_packswap(row_info, png_ptr->row_buf + 1); #endif -#if defined(PNG_READ_FILLER_SUPPORTED) +#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_do_read_filler(row_info, png_ptr->row_buf + 1, + (png_uint_32)png_ptr->filler, png_ptr->flags); #endif -#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED if (png_ptr->transformations & PNG_INVERT_ALPHA) - png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1); #endif -#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) +#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED if (png_ptr->transformations & PNG_SWAP_ALPHA) - png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); + png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1); #endif -#if defined(PNG_READ_SWAP_SUPPORTED) +#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); + png_do_swap(row_info, png_ptr->row_buf + 1); +#endif #endif -#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) +#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 */ -#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) - if(png_ptr->user_transform_depth) - png_ptr->row_info.bit_depth = png_ptr->user_transform_depth; - if(png_ptr->user_transform_channels) - png_ptr->row_info.channels = png_ptr->user_transform_channels; + if (png_ptr->read_user_transform_fn != NULL) + (*(png_ptr->read_user_transform_fn)) /* User read transform function */ + (png_ptr, /* png_ptr */ + row_info, /* row_info: */ + /* png_uint_32 width; width of row */ + /* png_size_t rowbytes; number of bytes in row */ + /* png_byte color_type; color type of pixels */ + /* png_byte bit_depth; bit depth of samples */ + /* png_byte channels; number of channels (1-4) */ + /* png_byte pixel_depth; bits per pixel (depth*channels) */ + png_ptr->row_buf + 1); /* start of pixel data for row */ +#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED + if (png_ptr->user_transform_depth) + row_info->bit_depth = png_ptr->user_transform_depth; + + if (png_ptr->user_transform_channels) + row_info->channels = png_ptr->user_transform_channels; #endif - png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth * - png_ptr->row_info.channels); - png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth, - png_ptr->row_info.width); + row_info->pixel_depth = (png_byte)(row_info->bit_depth * + row_info->channels); + + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width); } #endif - } -#if defined(PNG_READ_PACK_SUPPORTED) +#ifdef PNG_READ_PACK_SUPPORTED /* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel, * without changing the actual values. Thus, if you had a row with * a bit depth of 1, you would end up with bytes that only contained @@ -1403,12 +2368,9 @@ From Andreas Dilger e-mail to png-implement, 26 March 1998: void /* PRIVATE */ png_do_unpack(png_row_infop row_info, png_bytep row) { - png_debug(1, "in png_do_unpack\n"); -#if defined(PNG_USELESS_TESTS_SUPPORTED) - if (row != NULL && row_info != NULL && row_info->bit_depth < 8) -#else + png_debug(1, "in png_do_unpack"); + if (row_info->bit_depth < 8) -#endif { png_uint_32 i; png_uint_32 row_width=row_info->width; @@ -1423,11 +2385,13 @@ 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++; @@ -1435,6 +2399,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row) } break; } + case 2: { @@ -1444,11 +2409,13 @@ 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; @@ -1456,6 +2423,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row) } break; } + case 4: { png_bytep sp = row + (png_size_t)((row_width - 1) >> 1); @@ -1464,11 +2432,13 @@ 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; @@ -1476,6 +2446,9 @@ 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); @@ -1484,164 +2457,229 @@ png_do_unpack(png_row_infop row_info, png_bytep row) } #endif -#if defined(PNG_READ_SHIFT_SUPPORTED) +#ifdef PNG_READ_SHIFT_SUPPORTED /* Reverse the effects of png_do_shift. This routine merely shifts the * pixels back to their significant bits values. Thus, if you have * a row of bit depth 8, but only 5 are significant, this will shift * the values back to 0 through 31. */ void /* PRIVATE */ -png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) +png_do_unshift(png_row_infop row_info, png_bytep row, + png_const_color_8p sig_bits) { - png_debug(1, "in png_do_unshift\n"); - if ( -#if defined(PNG_USELESS_TESTS_SUPPORTED) - row != NULL && row_info != NULL && sig_bits != NULL && -#endif - row_info->color_type != PNG_COLOR_TYPE_PALETTE) + int color_type; + + png_debug(1, "in png_do_unshift"); + + /* The palette case has already been handled in the _init routine. */ + color_type = row_info->color_type; + + if (color_type != PNG_COLOR_TYPE_PALETTE) { int shift[4]; int channels = 0; - int c; - png_uint_16 value = 0; - png_uint_32 row_width = row_info->width; + int bit_depth = row_info->bit_depth; - if (row_info->color_type & PNG_COLOR_MASK_COLOR) + if (color_type & PNG_COLOR_MASK_COLOR) { - shift[channels++] = row_info->bit_depth - sig_bits->red; - shift[channels++] = row_info->bit_depth - sig_bits->green; - shift[channels++] = row_info->bit_depth - sig_bits->blue; + shift[channels++] = bit_depth - sig_bits->red; + shift[channels++] = bit_depth - sig_bits->green; + shift[channels++] = bit_depth - sig_bits->blue; } + else { - shift[channels++] = row_info->bit_depth - sig_bits->gray; + shift[channels++] = bit_depth - sig_bits->gray; } - if (row_info->color_type & PNG_COLOR_MASK_ALPHA) + + if (color_type & PNG_COLOR_MASK_ALPHA) { - shift[channels++] = row_info->bit_depth - sig_bits->alpha; + shift[channels++] = bit_depth - sig_bits->alpha; } - for (c = 0; c < channels; c++) { - if (shift[c] <= 0) - shift[c] = 0; - else - value = 1; - } + int c, have_shift; - if (!value) - return; + for (c = have_shift = 0; c < channels; ++c) + { + /* A shift of more than the bit depth is an error condition but it + * gets ignored here. + */ + if (shift[c] <= 0 || shift[c] >= bit_depth) + shift[c] = 0; - switch (row_info->bit_depth) + else + have_shift = 1; + } + + if (!have_shift) + return; + } + + switch (bit_depth) { + default: + /* Must be 1bpp gray: should not be here! */ + /* NOTREACHED */ + break; + case 2: + /* Must be 2bpp gray */ + /* assert(channels == 1 && shift[0] == 1) */ { - png_bytep bp; - png_uint_32 i; - png_uint_32 istop = row_info->rowbytes; + png_bytep bp = row; + png_bytep bp_end = bp + row_info->rowbytes; - for (bp = row, i = 0; i < istop; i++) + while (bp < bp_end) { - *bp >>= 1; - *bp++ &= 0x55; + int b = (*bp >> 1) & 0x55; + *bp++ = (png_byte)b; } break; } + case 4: + /* Must be 4bpp gray */ + /* assert(channels == 1) */ { png_bytep bp = row; - png_uint_32 i; - png_uint_32 istop = row_info->rowbytes; - png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) | - (png_byte)((int)0xf >> shift[0])); + png_bytep bp_end = bp + row_info->rowbytes; + int gray_shift = shift[0]; + int mask = 0xf >> gray_shift; - for (i = 0; i < istop; i++) + mask |= mask << 4; + + while (bp < bp_end) { - *bp >>= shift[0]; - *bp++ &= mask; + int b = (*bp >> gray_shift) & mask; + *bp++ = (png_byte)b; } break; } + case 8: + /* Single byte components, G, GA, RGB, RGBA */ { png_bytep bp = row; - png_uint_32 i; - png_uint_32 istop = row_width * channels; + png_bytep bp_end = bp + row_info->rowbytes; + int channel = 0; - for (i = 0; i < istop; i++) + while (bp < bp_end) { - *bp++ >>= shift[i%channels]; + int b = *bp >> shift[channel]; + if (++channel >= channels) + channel = 0; + *bp++ = (png_byte)b; } break; } + +#ifdef PNG_READ_16BIT_SUPPORTED case 16: + /* Double byte components, G, GA, RGB, RGBA */ { png_bytep bp = row; - png_uint_32 i; - png_uint_32 istop = channels * row_width; + png_bytep bp_end = bp + row_info->rowbytes; + int channel = 0; - for (i = 0; i < istop; i++) + while (bp < bp_end) { - value = (png_uint_16)((*bp << 8) + *(bp + 1)); - value >>= shift[i%channels]; + int value = (bp[0] << 8) + bp[1]; + + value >>= shift[channel]; + if (++channel >= channels) + channel = 0; *bp++ = (png_byte)(value >> 8); *bp++ = (png_byte)(value & 0xff); } break; } +#endif } } } #endif -#if defined(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\n"); -#if defined(PNG_USELESS_TESTS_SUPPORTED) - if (row != NULL && row_info != NULL && row_info->bit_depth == 16) -#else + png_debug(1, "in png_do_scale_16_to_8"); + if (row_info->bit_depth == 16) -#endif { - png_bytep sp = row; - png_bytep dp = row; - png_uint_32 i; - png_uint_32 istop = row_info->width * row_info->channels; + png_bytep sp = row; /* source */ + png_bytep dp = row; /* destination */ + png_bytep ep = sp + row_info->rowbytes; /* end+1 */ - for (i = 0; i> 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 + */ + + png_int_32 tmp = *sp++; /* must be signed! */ + tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24; + *dp++ = (png_byte)tmp; + } - *dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0); -#else - /* Simply discard the low order byte */ - *dp = *sp; + 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; /* destination */ + png_bytep ep = sp + row_info->rowbytes; /* end+1 */ + + while (sp < ep) + { + *dp++ = *sp; + sp += 2; /* skip low byte */ } + row_info->bit_depth = 8; row_info->pixel_depth = (png_byte)(8 * row_info->channels); row_info->rowbytes = row_info->width * row_info->channels; @@ -1649,14 +2687,12 @@ png_do_chop(png_row_infop row_info, png_bytep row) } #endif -#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) +#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED void /* PRIVATE */ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) { - png_debug(1, "in png_do_read_swap_alpha\n"); -#if defined(PNG_USELESS_TESTS_SUPPORTED) - if (row != NULL && row_info != NULL) -#endif + png_debug(1, "in png_do_read_swap_alpha"); + { png_uint_32 row_width = row_info->width; if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) @@ -1678,6 +2714,8 @@ 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 { @@ -1700,7 +2738,9 @@ 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 */ @@ -1718,6 +2758,8 @@ 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 { @@ -1736,133 +2778,137 @@ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) *(--dp) = save[1]; } } +#endif } } } #endif -#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED void /* PRIVATE */ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row) { - png_debug(1, "in png_do_read_invert_alpha\n"); -#if defined(PNG_USELESS_TESTS_SUPPORTED) - if (row != NULL && row_info != NULL) -#endif + 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 -#if defined(PNG_READ_FILLER_SUPPORTED) +#ifdef PNG_READ_FILLER_SUPPORTED /* Add filler channel if we have RGB color */ void /* PRIVATE */ png_do_read_filler(png_row_infop row_info, png_bytep row, - png_uint_32 filler, png_uint_32 flags) + png_uint_32 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\n"); + png_debug(1, "in png_do_read_filler"); + if ( -#if defined(PNG_USELESS_TESTS_SUPPORTED) - row != NULL && row_info != NULL && -#endif row_info->color_type == PNG_COLOR_TYPE_GRAY) { - if(row_info->bit_depth == 8) + 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++) @@ -1875,9 +2921,10 @@ 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++) @@ -1890,11 +2937,13 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, row_info->rowbytes = row_width * 2; } } - else if(row_info->bit_depth == 16) + +#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++) @@ -1910,9 +2959,10 @@ 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++) @@ -1927,15 +2977,15 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, row_info->rowbytes = row_width * 4; } } - row_info->color_type |= PNG_COLOR_MASK_ALPHA; +#endif } /* COLOR_TYPE == GRAY */ else if (row_info->color_type == PNG_COLOR_TYPE_RGB) { - if(row_info->bit_depth == 8) + 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++) @@ -1950,9 +3000,10 @@ 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++) @@ -1967,11 +3018,13 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, row_info->rowbytes = row_width * 4; } } - else if(row_info->bit_depth == 16) + +#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++) @@ -1991,9 +3044,10 @@ 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++) @@ -2007,35 +3061,35 @@ 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; } } - row_info->color_type |= PNG_COLOR_MASK_ALPHA; +#endif } /* COLOR_TYPE == RGB */ } #endif -#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) -/* expand grayscale files to RGB, with or without alpha */ +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED +/* Expand grayscale files to RGB, with or without alpha */ void /* PRIVATE */ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) { png_uint_32 i; png_uint_32 row_width = row_info->width; - png_debug(1, "in png_do_gray_to_rgb\n"); + png_debug(1, "in png_do_gray_to_rgb"); + if (row_info->bit_depth >= 8 && -#if defined(PNG_USELESS_TESTS_SUPPORTED) - row != NULL && row_info != NULL && -#endif - !(row_info->color_type & PNG_COLOR_MASK_COLOR)) + !(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++) @@ -2045,8 +3099,10 @@ 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++) @@ -2060,10 +3116,12 @@ 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++) @@ -2074,8 +3132,10 @@ 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++) @@ -2091,273 +3151,269 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) } } } - row_info->channels += (png_byte)2; + row_info->channels = (png_byte)(row_info->channels + 2); row_info->color_type |= PNG_COLOR_MASK_COLOR; row_info->pixel_depth = (png_byte)(row_info->channels * - row_info->bit_depth); - row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width); + row_info->bit_depth); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); } } #endif -#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) -/* reduce RGB files to grayscale, with or without alpha - * using the equation given in Poynton's ColorFAQ at - * - * Copyright (c) 1998-01-04 Charles Poynton poynton@inforamp.net +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +/* Reduce RGB files to grayscale, with or without alpha + * using the equation given in Poynton's ColorFAQ of 1998-01-04 at + * (THIS LINK IS DEAD June 2008 but + * versions dated 1998 through November 2002 have been archived at + * http://web.archive.org/web/20000816232553/http://www.inforamp.net/ + * ~poynton/notes/colour_and_gamma/ColorFAQ.txt ) + * Charles Poynton poynton at poynton.com * * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B * - * We approximate this with + * which can be expressed with integers as + * + * Y = (6969 * R + 23434 * G + 2365 * B)/32768 + * + * Poynton's current link (as of January 2003 through July 2011): + * + * has changed the numbers slightly: * - * Y = 0.21268 * R + 0.7151 * G + 0.07217 * B + * Y = 0.2126*R + 0.7152*G + 0.0722*B * * which can be expressed with integers as * - * Y = (6969 * R + 23434 * G + 2365 * B)/32768 + * Y = (6966 * R + 23436 * G + 2366 * B)/32768 * - * The calculation is to be done in a linear colorspace. + * Historically, however, libpng uses numbers derived from the ITU-R Rec 709 + * end point chromaticities and the D65 white point. Depending on the + * precision used for the D65 white point this produces a variety of different + * numbers, however if the four decimal place value used in ITU-R Rec 709 is + * used (0.3127,0.3290) the Y calculation would be: * - * Other integer coefficents can be used via png_set_rgb_to_gray(). + * Y = (6968 * R + 23435 * G + 2366 * B)/32768 + * + * While this is correct the rounding results in an overflow for white, because + * the sum of the rounded coefficients is 32769, not 32768. Consequently + * libpng uses, instead, the closest non-overflowing approximation: + * + * Y = (6968 * R + 23434 * G + 2366 * B)/32768 + * + * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk + * (including an sRGB chunk) then the chromaticities are used to calculate the + * coefficients. See the chunk handling in pngrutil.c for more information. + * + * In all cases the calculation is to be done in a linear colorspace. If no + * gamma information is available to correct the encoding of the original RGB + * values this results in an implicit assumption that the original PNG RGB + * values were linear. + * + * Other integer coefficents can be used via png_set_rgb_to_gray(). Because + * the API takes just red and green coefficients the blue coefficient is + * calculated to make the sum 32768. This will result in different rounding + * to that used above. */ int /* PRIVATE */ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row) { - png_uint_32 i; - - png_uint_32 row_width = row_info->width; int rgb_error = 0; - png_debug(1, "in png_do_rgb_to_gray\n"); - if ( -#if defined(PNG_USELESS_TESTS_SUPPORTED) - row != NULL && row_info != NULL && -#endif - (row_info->color_type & PNG_COLOR_MASK_COLOR)) + png_debug(1, "in png_do_rgb_to_gray"); + + 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; - png_uint_32 bc = png_ptr->rgb_to_gray_blue_coeff; + PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff; + PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff; + PNG_CONST png_uint_32 bc = 32768 - rc - gc; + PNG_CONST png_uint_32 row_width = row_info->width; + PNG_CONST int have_alpha = + (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0; - if (row_info->color_type == PNG_COLOR_TYPE_RGB) + if (row_info->bit_depth == 8) { - if (row_info->bit_depth == 8) - { #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL) - { - png_bytep sp = row; - png_bytep dp = row; + /* Notice that gamma to/from 1 are not necessarily inverses (if + * there is an overall gamma correction). Prior to 1.5.5 this code + * checked the linearized values for equality; this doesn't match + * the documentation, the original values must be checked. + */ + if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL) + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; - for (i = 0; i < row_width; i++) - { - png_byte red = png_ptr->gamma_to_1[*(sp++)]; - png_byte green = png_ptr->gamma_to_1[*(sp++)]; - png_byte blue = png_ptr->gamma_to_1[*(sp++)]; - if(red != green || red != blue) - { - rgb_error |= 1; - *(dp++) = png_ptr->gamma_from_1[ - (rc*red+gc*green+bc*blue)>>15]; - } - else - *(dp++) = *(sp-1); - } - } - else -#endif + for (i = 0; i < row_width; i++) { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) - { - png_byte red = *(sp++); - png_byte green = *(sp++); - png_byte blue = *(sp++); - if(red != green || red != blue) - { - rgb_error |= 1; - *(dp++) = (png_byte)((rc*red+gc*green+bc*blue)>>15); - } - else - *(dp++) = *(sp-1); - } - } - } + png_byte red = *(sp++); + png_byte green = *(sp++); + png_byte blue = *(sp++); - else /* RGB bit_depth == 16 */ - { -#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->gamma_16_to_1 != NULL && - png_ptr->gamma_16_from_1 != NULL) - { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) + if (red != green || red != blue) { - png_uint_16 red, green, blue, w; + red = png_ptr->gamma_to_1[red]; + green = png_ptr->gamma_to_1[green]; + blue = png_ptr->gamma_to_1[blue]; - 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; + rgb_error |= 1; + *(dp++) = png_ptr->gamma_from_1[ + (rc*red + gc*green + bc*blue + 16384)>>15]; + } - if(red == green && red == blue) - w = red; - else - { - png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >> - png_ptr->gamma_shift][red>>8]; - png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >> - png_ptr->gamma_shift][green>>8]; - png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >> - png_ptr->gamma_shift][blue>>8]; - png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1 - + bc*blue_1)>>15); - w = png_ptr->gamma_16_from_1[(gray16&0xff) >> - png_ptr->gamma_shift][gray16 >> 8]; - rgb_error |= 1; - } + else + { + /* If there is no overall correction the table will not be + * set. + */ + if (png_ptr->gamma_table != NULL) + red = png_ptr->gamma_table[red]; - *(dp++) = (png_byte)((w>>8) & 0xff); - *(dp++) = (png_byte)(w & 0xff); + *(dp++) = red; } + + if (have_alpha) + *(dp++) = *(sp++); } - else + } + else #endif + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; + + for (i = 0; i < row_width; i++) { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) + png_byte red = *(sp++); + png_byte green = *(sp++); + png_byte blue = *(sp++); + + if (red != green || red != blue) { - png_uint_16 red, green, blue, gray16; + rgb_error |= 1; + /*NOTE: this is the historical approach which simply + * truncates the results. + */ + *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15); + } - 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; + else + *(dp++) = red; - if(red != green || red != blue) - rgb_error |= 1; - gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15); - *(dp++) = (png_byte)((gray16>>8) & 0xff); - *(dp++) = (png_byte)(gray16 & 0xff); - } + if (have_alpha) + *(dp++) = *(sp++); } } } - if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + + else /* RGB bit_depth == 16 */ { - if (row_info->bit_depth == 8) - { #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL) + if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL) + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; + + for (i = 0; i < row_width; i++) { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) + png_uint_16 red, green, blue, w; + + red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + + if (red == green && red == blue) { - png_byte red = png_ptr->gamma_to_1[*(sp++)]; - png_byte green = png_ptr->gamma_to_1[*(sp++)]; - png_byte blue = png_ptr->gamma_to_1[*(sp++)]; - if(red != green || red != blue) - rgb_error |= 1; - *(dp++) = png_ptr->gamma_from_1 - [(rc*red + gc*green + bc*blue)>>15]; - *(dp++) = *(sp++); /* alpha */ + if (png_ptr->gamma_16_table != NULL) + w = png_ptr->gamma_16_table[(red&0xff) + >> png_ptr->gamma_shift][red>>8]; + + else + w = red; } - } - else -#endif - { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) + + else { - png_byte red = *(sp++); - png_byte green = *(sp++); - png_byte blue = *(sp++); - if(red != green || red != blue) - rgb_error |= 1; - *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15); - *(dp++) = *(sp++); /* alpha */ + png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) + >> png_ptr->gamma_shift][red>>8]; + png_uint_16 green_1 = + png_ptr->gamma_16_to_1[(green&0xff) >> + png_ptr->gamma_shift][green>>8]; + png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) + >> png_ptr->gamma_shift][blue>>8]; + png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1 + + bc*blue_1 + 16384)>>15); + w = png_ptr->gamma_16_from_1[(gray16&0xff) >> + png_ptr->gamma_shift][gray16 >> 8]; + rgb_error |= 1; } - } - } - else /* RGBA bit_depth == 16 */ - { -#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->gamma_16_to_1 != NULL && - png_ptr->gamma_16_from_1 != NULL) - { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) - { - png_uint_16 red, green, blue, w; - red = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; - green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; - blue = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2; - - if(red == green && red == blue) - w = red; - else - { - png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >> - png_ptr->gamma_shift][red>>8]; - png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >> - png_ptr->gamma_shift][green>>8]; - png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >> - png_ptr->gamma_shift][blue>>8]; - png_uint_16 gray16 = (png_uint_16)((rc * red_1 - + gc * green_1 + bc * blue_1)>>15); - w = png_ptr->gamma_16_from_1[(gray16&0xff) >> - png_ptr->gamma_shift][gray16 >> 8]; - rgb_error |= 1; - } + *(dp++) = (png_byte)((w>>8) & 0xff); + *(dp++) = (png_byte)(w & 0xff); - *(dp++) = (png_byte)((w>>8) & 0xff); - *(dp++) = (png_byte)(w & 0xff); - *(dp++) = *(sp++); /* alpha */ + if (have_alpha) + { + *(dp++) = *(sp++); *(dp++) = *(sp++); } } - else + } + else #endif + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; + + for (i = 0; i < row_width; i++) { - png_bytep sp = row; - png_bytep dp = row; - for (i = 0; i < row_width; i++) + png_uint_16 red, green, blue, gray16; + + red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + + if (red != green || red != blue) + rgb_error |= 1; + + /* From 1.5.5 in the 16 bit case do the accurate conversion even + * in the 'fast' case - this is because this is where the code + * ends up when handling linear 16 bit data. + */ + gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >> + 15); + *(dp++) = (png_byte)((gray16>>8) & 0xff); + *(dp++) = (png_byte)(gray16 & 0xff); + + if (have_alpha) { - png_uint_16 red, green, blue, gray16; - red = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2; - green = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2; - blue = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2; - if(red != green || red != blue) - rgb_error |= 1; - gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15); - *(dp++) = (png_byte)((gray16>>8) & 0xff); - *(dp++) = (png_byte)(gray16 & 0xff); - *(dp++) = *(sp++); /* alpha */ + *(dp++) = *(sp++); *(dp++) = *(sp++); } } } } - row_info->channels -= (png_byte)2; - row_info->color_type &= ~PNG_COLOR_MASK_COLOR; + + row_info->channels = (png_byte)(row_info->channels - 2); + row_info->color_type = (png_byte)(row_info->color_type & + ~PNG_COLOR_MASK_COLOR); row_info->pixel_depth = (png_byte)(row_info->channels * - row_info->bit_depth); - row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width); + 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) @@ -2367,7 +3423,8 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette) int i; int v; - png_debug(1, "in png_do_build_grayscale_palette\n"); + png_debug(1, "in png_do_build_grayscale_palette"); + if (palette == NULL) return; @@ -2377,18 +3434,22 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette) num_palette = 2; color_inc = 0xff; break; + case 2: num_palette = 4; color_inc = 0x55; break; + case 4: num_palette = 16; color_inc = 0x11; break; + case 8: num_palette = 256; color_inc = 1; break; + default: num_palette = 0; color_inc = 0; @@ -2402,217 +3463,37 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette) palette[i].blue = (png_byte)v; } } - -/* This function is currently unused. Do we really need it? */ -#if defined(PNG_READ_DITHER_SUPPORTED) && defined(PNG_CORRECT_PALETTE_SUPPORTED) -void /* PRIVATE */ -png_correct_palette(png_structp png_ptr, png_colorp palette, - int num_palette) -{ - png_debug(1, "in png_correct_palette\n"); -#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ - defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED) - if (png_ptr->transformations & (PNG_GAMMA | PNG_BACKGROUND)) - { - png_color back, back_1; - - if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE) - { - back.red = png_ptr->gamma_table[png_ptr->background.red]; - back.green = png_ptr->gamma_table[png_ptr->background.green]; - back.blue = png_ptr->gamma_table[png_ptr->background.blue]; - - back_1.red = png_ptr->gamma_to_1[png_ptr->background.red]; - back_1.green = png_ptr->gamma_to_1[png_ptr->background.green]; - back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue]; - } - else - { - double g; - - g = 1.0 / (png_ptr->background_gamma * png_ptr->screen_gamma); - - if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_SCREEN || - fabs(g - 1.0) < PNG_GAMMA_THRESHOLD) - { - back.red = png_ptr->background.red; - back.green = png_ptr->background.green; - back.blue = png_ptr->background.blue; - } - else - { - back.red = - (png_byte)(pow((double)png_ptr->background.red/255, g) * - 255.0 + 0.5); - back.green = - (png_byte)(pow((double)png_ptr->background.green/255, g) * - 255.0 + 0.5); - back.blue = - (png_byte)(pow((double)png_ptr->background.blue/255, g) * - 255.0 + 0.5); - } - - g = 1.0 / png_ptr->background_gamma; - - back_1.red = - (png_byte)(pow((double)png_ptr->background.red/255, g) * - 255.0 + 0.5); - back_1.green = - (png_byte)(pow((double)png_ptr->background.green/255, g) * - 255.0 + 0.5); - back_1.blue = - (png_byte)(pow((double)png_ptr->background.blue/255, g) * - 255.0 + 0.5); - } - - if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) - { - png_uint_32 i; - - for (i = 0; i < (png_uint_32)num_palette; i++) - { - if (i < png_ptr->num_trans && png_ptr->trans[i] == 0) - { - palette[i] = back; - } - else if (i < png_ptr->num_trans && png_ptr->trans[i] != 0xff) - { - png_byte v, w; - - v = png_ptr->gamma_to_1[png_ptr->palette[i].red]; - png_composite(w, v, png_ptr->trans[i], back_1.red); - palette[i].red = png_ptr->gamma_from_1[w]; - - v = png_ptr->gamma_to_1[png_ptr->palette[i].green]; - png_composite(w, v, png_ptr->trans[i], back_1.green); - palette[i].green = png_ptr->gamma_from_1[w]; - - v = png_ptr->gamma_to_1[png_ptr->palette[i].blue]; - png_composite(w, v, png_ptr->trans[i], back_1.blue); - palette[i].blue = png_ptr->gamma_from_1[w]; - } - else - { - palette[i].red = png_ptr->gamma_table[palette[i].red]; - palette[i].green = png_ptr->gamma_table[palette[i].green]; - palette[i].blue = png_ptr->gamma_table[palette[i].blue]; - } - } - } - else - { - int i; - - for (i = 0; i < num_palette; i++) - { - if (palette[i].red == (png_byte)png_ptr->trans_values.gray) - { - palette[i] = back; - } - else - { - palette[i].red = png_ptr->gamma_table[palette[i].red]; - palette[i].green = png_ptr->gamma_table[palette[i].green]; - palette[i].blue = png_ptr->gamma_table[palette[i].blue]; - } - } - } - } - else #endif -#if defined(PNG_READ_GAMMA_SUPPORTED) - if (png_ptr->transformations & PNG_GAMMA) - { - int i; - - for (i = 0; i < num_palette; i++) - { - palette[i].red = png_ptr->gamma_table[palette[i].red]; - palette[i].green = png_ptr->gamma_table[palette[i].green]; - palette[i].blue = png_ptr->gamma_table[palette[i].blue]; - } - } -#if defined(PNG_READ_BACKGROUND_SUPPORTED) - else -#endif -#endif -#if defined(PNG_READ_BACKGROUND_SUPPORTED) - if (png_ptr->transformations & PNG_BACKGROUND) - { - if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) - { - png_color back; - - back.red = (png_byte)png_ptr->background.red; - back.green = (png_byte)png_ptr->background.green; - back.blue = (png_byte)png_ptr->background.blue; - - for (i = 0; i < (int)png_ptr->num_trans; i++) - { - if (png_ptr->trans[i] == 0) - { - palette[i].red = back.red; - palette[i].green = back.green; - palette[i].blue = back.blue; - } - else if (png_ptr->trans[i] != 0xff) - { - png_composite(palette[i].red, png_ptr->palette[i].red, - png_ptr->trans[i], back.red); - png_composite(palette[i].green, png_ptr->palette[i].green, - png_ptr->trans[i], back.green); - png_composite(palette[i].blue, png_ptr->palette[i].blue, - png_ptr->trans[i], back.blue); - } - } - } - else /* assume grayscale palette (what else could it be?) */ - { - int i; - for (i = 0; i < num_palette; i++) - { - if (i == (png_byte)png_ptr->trans_values.gray) - { - palette[i].red = (png_byte)png_ptr->background.red; - palette[i].green = (png_byte)png_ptr->background.green; - palette[i].blue = (png_byte)png_ptr->background.blue; - } - } - } - } -#endif -} -#endif -#if defined(PNG_READ_BACKGROUND_SUPPORTED) +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\ + (defined PNG_READ_ALPHA_MODE_SUPPORTED) /* Replace any alpha or transparency with the supplied background color. * "background" is already in the screen gamma, while "background_1" is * at a gamma of 1.0. Paletted files have already been taken care of. */ void /* PRIVATE */ -png_do_background(png_row_infop row_info, png_bytep row, - png_color_16p trans_values, png_color_16p background -#if defined(PNG_READ_GAMMA_SUPPORTED) - , png_color_16p background_1, - png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1, - png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1, - png_uint_16pp gamma_16_to_1, int gamma_shift -#endif - ) +png_do_compose(png_row_infop row_info, png_bytep row, png_structp png_ptr) { - png_bytep sp, dp; +#ifdef PNG_READ_GAMMA_SUPPORTED + png_const_bytep gamma_table = png_ptr->gamma_table; + png_const_bytep gamma_from_1 = png_ptr->gamma_from_1; + png_const_bytep gamma_to_1 = png_ptr->gamma_to_1; + png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table; + png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1; + png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1; + int gamma_shift = png_ptr->gamma_shift; +#endif + + 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\n"); - if (background != NULL && -#if defined(PNG_USELESS_TESTS_SUPPORTED) - row != NULL && row_info != NULL && -#endif - (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) || - (row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_values))) + png_debug(1, "in png_do_compose"); + { switch (row_info->color_type) { @@ -2627,24 +3508,27 @@ 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_values->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--; } break; } + case 2: { -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_table != NULL) { sp = row; @@ -2652,11 +3536,12 @@ 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_values->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); @@ -2665,15 +3550,18 @@ 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 { @@ -2682,25 +3570,28 @@ 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_values->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; } } break; } + case 4: { -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_table != NULL) { sp = row; @@ -2708,28 +3599,32 @@ 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_values->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 { @@ -2738,38 +3633,38 @@ 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_values->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; } } break; } + case 8: { -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_table != NULL) { sp = row; for (i = 0; i < row_width; i++, sp++) { - if (*sp == trans_values->gray) - { - *sp = (png_byte)background->gray; - } + if (*sp == png_ptr->trans_color.gray) + *sp = (png_byte)png_ptr->background.gray; + else - { *sp = gamma_table[*sp]; - } } } else @@ -2778,17 +3673,16 @@ png_do_background(png_row_infop row_info, png_bytep row, sp = row; for (i = 0; i < row_width; i++, sp++) { - if (*sp == trans_values->gray) - { - *sp = (png_byte)background->gray; - } + if (*sp == png_ptr->trans_color.gray) + *sp = (png_byte)png_ptr->background.gray; } } break; } + case 16: { -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_16 != NULL) { sp = row; @@ -2797,12 +3691,14 @@ 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_values->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); + /* Background is already in screen gamma */ + *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); } + else { v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; @@ -2820,36 +3716,42 @@ 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_values->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; } + case PNG_COLOR_TYPE_RGB: { if (row_info->bit_depth == 8) { -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_table != NULL) { sp = row; for (i = 0; i < row_width; i++, sp += 3) { - if (*sp == trans_values->red && - *(sp + 1) == trans_values->green && - *(sp + 2) == trans_values->blue) + 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]; @@ -2864,108 +3766,125 @@ 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_values->red && - *(sp + 1) == trans_values->green && - *(sp + 2) == trans_values->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 /* if (row_info->bit_depth == 16) */ { -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_16 != NULL) { sp = row; for (i = 0; i < row_width; i++, sp += 6) { png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1)); - png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3)); - png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5)); - if (r == trans_values->red && g == trans_values->green && - b == trans_values->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); + /* Background is already in screen gamma */ + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); } + else { png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; *sp = (png_byte)((v >> 8) & 0xff); *(sp + 1) = (png_byte)(v & 0xff); + v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)]; *(sp + 2) = (png_byte)((v >> 8) & 0xff); *(sp + 3) = (png_byte)(v & 0xff); + v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)]; *(sp + 4) = (png_byte)((v >> 8) & 0xff); *(sp + 5) = (png_byte)(v & 0xff); } } } + else #endif { sp = row; for (i = 0; i < row_width; i++, sp += 6) { - png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp+1)); - png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3)); - png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5)); + png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + + png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8) + + *(sp + 3)); + + png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8) + + *(sp + 5)); - if (r == trans_values->red && g == trans_values->green && - b == trans_values->blue) + 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); } } } } break; } + case PNG_COLOR_TYPE_GRAY_ALPHA: { if (row_info->bit_depth == 8) { -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_to_1 != NULL && gamma_from_1 != NULL && gamma_table != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 2, dp++) + 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; + /* Background is already in screen gamma */ + *sp = (png_byte)png_ptr->background.gray; } + else { png_byte v, w; v = gamma_to_1[*sp]; - png_composite(w, v, a, 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; } } } @@ -2973,151 +3892,137 @@ 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; - } -#if defined(PNG_READ_GAMMA_SUPPORTED) - else if (a == 0) - { - *dp = (png_byte)background->gray; - } - else - { - png_composite(*dp, *sp, a, background_1->gray); - } -#else - *dp = (png_byte)background->gray; -#endif + if (a == 0) + *sp = (png_byte)png_ptr->background.gray; + + else if (a < 0xff) + png_composite(*sp, *sp, a, png_ptr->background_1.gray); } } } else /* if (png_ptr->bit_depth == 16) */ { -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_16 != NULL && gamma_16_from_1 != NULL && gamma_16_to_1 != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 4, dp += 2) + 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); } -#if defined(PNG_READ_GAMMA_SUPPORTED) + else if (a == 0) -#else - else -#endif { - /* background is already in screen gamma */ - *dp = (png_byte)((background->gray >> 8) & 0xff); - *(dp + 1) = (png_byte)(background->gray & 0xff); + /* Background is already in screen gamma */ + *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); } -#if defined(PNG_READ_GAMMA_SUPPORTED) + else { png_uint_16 g, v, w; g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp]; - png_composite_16(v, g, a, background_1->gray); - w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8]; - *dp = (png_byte)((w >> 8) & 0xff); - *(dp + 1) = (png_byte)(w & 0xff); + 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); - } -#if defined(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); } -#if defined(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 } } } break; } + case PNG_COLOR_TYPE_RGB_ALPHA: { if (row_info->bit_depth == 8) { -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_to_1 != NULL && gamma_from_1 != NULL && gamma_table != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 4, dp += 3) + 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; + /* Background is already in screen gamma */ + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; } + else { png_byte v, w; v = gamma_to_1[*sp]; - png_composite(w, v, a, 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; } } } @@ -3125,115 +4030,120 @@ 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); } } } } else /* if (row_info->bit_depth == 16) */ { -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED if (gamma_16 != NULL && gamma_16_from_1 != NULL && gamma_16_to_1 != NULL) { sp = row; - dp = row; - for (i = 0; i < row_width; i++, sp += 8, dp += 6) + 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); + /* Background is already in screen gamma */ + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); } + else { - png_uint_16 v, w, 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; @@ -3243,36 +4153,32 @@ 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; } } } -#endif +#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_READ_ALPHA_MODE_SUPPORTED */ -#if defined(PNG_READ_GAMMA_SUPPORTED) +#ifdef PNG_READ_GAMMA_SUPPORTED /* Gamma correct the image, avoiding the alpha channel. Make sure * you do this after you deal with the transparency issue on grayscale * or RGB images. If your bit depth is 8, use gamma_table, if it @@ -3280,21 +4186,20 @@ 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\n"); - if ( -#if defined(PNG_USELESS_TESTS_SUPPORTED) - row != NULL && row_info != NULL && -#endif - ((row_info->bit_depth <= 8 && gamma_table != NULL) || - (row_info->bit_depth == 16 && gamma_16_table != NULL))) + png_debug(1, "in png_do_gamma"); + + if (((row_info->bit_depth <= 8 && gamma_table != NULL) || + (row_info->bit_depth == 16 && gamma_16_table != NULL))) { switch (row_info->color_type) { @@ -3313,6 +4218,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, sp++; } } + else /* if (row_info->bit_depth == 16) */ { sp = row; @@ -3324,10 +4230,12 @@ 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); @@ -3336,6 +4244,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, } break; } + case PNG_COLOR_TYPE_RGB_ALPHA: { if (row_info->bit_depth == 8) @@ -3345,13 +4254,17 @@ 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; @@ -3361,10 +4274,12 @@ 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); @@ -3373,6 +4288,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, } break; } + case PNG_COLOR_TYPE_GRAY_ALPHA: { if (row_info->bit_depth == 8) @@ -3384,6 +4300,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, sp += 2; } } + else /* if (row_info->bit_depth == 16) */ { sp = row; @@ -3397,6 +4314,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, } break; } + case PNG_COLOR_TYPE_GRAY: { if (row_info->bit_depth == 2) @@ -3410,13 +4328,14 @@ 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++; } } + if (row_info->bit_depth == 4) { sp = row; @@ -3426,10 +4345,11 @@ 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++; } } + else if (row_info->bit_depth == 8) { sp = row; @@ -3439,6 +4359,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, sp++; } } + else if (row_info->bit_depth == 16) { sp = row; @@ -3452,30 +4373,97 @@ 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 -#if defined(PNG_READ_EXPAND_SUPPORTED) +#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, int num_trans) + png_const_colorp palette, png_const_bytep trans_alpha, int num_trans) { int shift, value; png_bytep sp, dp; png_uint_32 i; png_uint_32 row_width=row_info->width; - png_debug(1, "in png_do_expand_palette\n"); - if ( -#if defined(PNG_USELESS_TESTS_SUPPORTED) - row != NULL && row_info != NULL && -#endif - row_info->color_type == PNG_COLOR_TYPE_PALETTE) + png_debug(1, "in png_do_expand_palette"); + + if (row_info->color_type == PNG_COLOR_TYPE_PALETTE) { if (row_info->bit_depth < 8) { @@ -3490,13 +4478,16 @@ 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++; @@ -3504,6 +4495,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, } break; } + case 2: { sp = row + (png_size_t)((row_width - 1) >> 2); @@ -3518,6 +4510,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, shift = 0; sp--; } + else shift += 2; @@ -3525,6 +4518,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, } break; } + case 4: { sp = row + (png_size_t)((row_width - 1) >> 1); @@ -3539,6 +4533,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, shift = 0; sp--; } + else shift += 4; @@ -3546,16 +4541,19 @@ 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 != NULL) + if (num_trans > 0) { sp = row + (png_size_t)row_width - 1; dp = row + (png_size_t)(row_width << 2) - 1; @@ -3564,8 +4562,10 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, { if ((int)(*sp) >= num_trans) *dp-- = 0xff; + else - *dp-- = trans[*sp]; + *dp-- = trans_alpha[*sp]; + *dp-- = palette[*sp].blue; *dp-- = palette[*sp].green; *dp-- = palette[*sp].red; @@ -3577,6 +4577,7 @@ 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; @@ -3589,38 +4590,36 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, *dp-- = palette[*sp].red; sp--; } + row_info->bit_depth = 8; row_info->pixel_depth = 24; row_info->rowbytes = row_width * 3; row_info->color_type = 2; row_info->channels = 3; } - break; } } } } -/* If the bit depth < 8, it is expanded to 8. Also, if the - * transparency value is supplied, an alpha channel is built. +/* If the bit depth < 8, it is expanded to 8. Also, if the already + * expanded transparency value is supplied, an alpha channel is built. */ void /* PRIVATE */ png_do_expand(png_row_infop row_info, png_bytep row, - png_color_16p trans_value) + png_const_color_16p trans_color) { int shift, value; png_bytep sp, dp; png_uint_32 i; png_uint_32 row_width=row_info->width; - png_debug(1, "in png_do_expand\n"); -#if defined(PNG_USELESS_TESTS_SUPPORTED) - if (row != NULL && row_info != NULL) -#endif + png_debug(1, "in png_do_expand"); + { if (row_info->color_type == PNG_COLOR_TYPE_GRAY) { - png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0); + png_uint_16 gray = (png_uint_16)(trans_color ? trans_color->gray : 0); if (row_info->bit_depth < 8) { @@ -3628,7 +4627,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, { case 1: { - gray = (png_uint_16)(gray*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); @@ -3636,13 +4635,16 @@ 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++; @@ -3650,9 +4652,10 @@ png_do_expand(png_row_infop row_info, png_bytep row, } break; } + case 2: { - gray = (png_uint_16)(gray*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); @@ -3666,6 +4669,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, shift = 0; sp--; } + else shift += 2; @@ -3673,9 +4677,10 @@ png_do_expand(png_row_infop row_info, png_bytep row, } break; } + case 4: { - gray = (png_uint_16)(gray*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); @@ -3688,6 +4693,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, shift = 0; sp--; } + else shift = 4; @@ -3695,48 +4701,61 @@ png_do_expand(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; } - 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 = (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++) { - if (((png_uint_16)*(sp) | - ((png_uint_16)*(sp - 1) << 8)) == gray) + if (*(sp - 1) == gray_high && *(sp) == gray_low) { *dp-- = 0; *dp-- = 0; } + else { *dp-- = 0xff; *dp-- = 0xff; } + *dp-- = *sp--; *dp-- = *sp--; } } + row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA; row_info->channels = 2; row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1); @@ -3744,20 +4763,23 @@ 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 = (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) == trans_value->red && - *(sp - 1) == trans_value->green && - *(sp - 0) == trans_value->blue) + if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue) *dp-- = 0; + else *dp-- = 0xff; + *dp-- = *sp--; *dp-- = *sp--; *dp-- = *sp--; @@ -3765,25 +4787,33 @@ png_do_expand(png_row_infop row_info, png_bytep row, } else if (row_info->bit_depth == 16) { + png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff); + png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff); + png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff); + png_byte red_low = (png_byte)(trans_color->red & 0xff); + png_byte green_low = (png_byte)(trans_color->green & 0xff); + png_byte blue_low = (png_byte)(trans_color->blue & 0xff); sp = row + row_info->rowbytes - 1; dp = row + (png_size_t)(row_width << 3) - 1; for (i = 0; i < row_width; i++) { - if ((((png_uint_16)*(sp - 4) | - ((png_uint_16)*(sp - 5) << 8)) == trans_value->red) && - (((png_uint_16)*(sp - 2) | - ((png_uint_16)*(sp - 3) << 8)) == trans_value->green) && - (((png_uint_16)*(sp - 0) | - ((png_uint_16)*(sp - 1) << 8)) == trans_value->blue)) + if (*(sp - 5) == red_high && + *(sp - 4) == red_low && + *(sp - 3) == green_high && + *(sp - 2) == green_low && + *(sp - 1) == blue_high && + *(sp ) == blue_low) { *dp-- = 0; *dp-- = 0; } + else { *dp-- = 0xff; *dp-- = 0xff; } + *dp-- = *sp--; *dp-- = *sp--; *dp-- = *sp--; @@ -3795,28 +4825,57 @@ png_do_expand(png_row_infop row_info, png_bytep row, row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA; row_info->channels = 4; row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2); - row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); } } } #endif -#if defined(PNG_READ_DITHER_SUPPORTED) +#ifdef PNG_READ_EXPAND_16_SUPPORTED +/* If the bit depth is 8 and the color type is not a palette type expand the + * whole row to 16 bits. Has no effect otherwise. + */ +void /* PRIVATE */ +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_dither(png_row_infop row_info, png_bytep row, - png_bytep palette_lookup, png_bytep dither_lookup) +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\n"); -#if defined(PNG_USELESS_TESTS_SUPPORTED) - if (row != NULL && row_info != NULL) -#endif + 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; @@ -3827,31 +4886,33 @@ png_do_dither(png_row_infop row_info, png_bytep row, g = *sp++; b = *sp++; - /* this looks real messy, but the compiler will reduce - it down to a reasonable formula. For example, with - 5 bits per color, we get: - p = (((r >> 3) & 0x1f) << 10) | - (((g >> 3) & 0x1f) << 5) | - ((b >> 3) & 0x1f); - */ - p = (((r >> (8 - PNG_DITHER_RED_BITS)) & - ((1 << PNG_DITHER_RED_BITS) - 1)) << - (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) | - (((g >> (8 - PNG_DITHER_GREEN_BITS)) & - ((1 << PNG_DITHER_GREEN_BITS) - 1)) << - (PNG_DITHER_BLUE_BITS)) | - ((b >> (8 - PNG_DITHER_BLUE_BITS)) & - ((1 << PNG_DITHER_BLUE_BITS) - 1)); + /* This looks real messy, but the compiler will reduce + * it down to a reasonable formula. For example, with + * 5 bits per color, we get: + * p = (((r >> 3) & 0x1f) << 10) | + * (((g >> 3) & 0x1f) << 5) | + * ((b >> 3) & 0x1f); + */ + p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) & + ((1 << PNG_QUANTIZE_RED_BITS) - 1)) << + (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) | + (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) & + ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) << + (PNG_QUANTIZE_BLUE_BITS)) | + ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) & + ((1 << PNG_QUANTIZE_BLUE_BITS) - 1)); *dp++ = palette_lookup[p]; } + row_info->color_type = PNG_COLOR_TYPE_PALETTE; row_info->channels = 1; row_info->pixel_depth = row_info->bit_depth; - row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width); + 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; @@ -3863,272 +4924,52 @@ 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); + 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]; - } - } - } -} -#endif - -#ifdef PNG_FLOATING_POINT_SUPPORTED -#if defined(PNG_READ_GAMMA_SUPPORTED) -static int png_gamma_shift[] = - {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0}; - -/* We build the 8- or 16-bit gamma tables here. Note that for 16-bit - * tables, we don't make a full table if we are reducing to 8-bit in - * the future. Note also how the gamma_16 tables are segmented so that - * we don't need to allocate > 64K chunks for a full 16-bit table. - */ -void /* PRIVATE */ -png_build_gamma_table(png_structp png_ptr) -{ - png_debug(1, "in png_build_gamma_table\n"); - if(png_ptr->gamma != 0.0) - { - if (png_ptr->bit_depth <= 8) - { - int i; - double g; - - if (png_ptr->screen_gamma > .000001) - g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); - else - g = 1.0; - - png_ptr->gamma_table = (png_bytep)png_malloc(png_ptr, - (png_uint_32)256); - - for (i = 0; i < 256; i++) - { - png_ptr->gamma_table[i] = (png_byte)(pow((double)i / 255.0, - g) * 255.0 + .5); - } - -#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ - defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) - if (png_ptr->transformations & ((PNG_BACKGROUND) | PNG_RGB_TO_GRAY)) - { - - g = 1.0 / (png_ptr->gamma); - - png_ptr->gamma_to_1 = (png_bytep)png_malloc(png_ptr, - (png_uint_32)256); - - for (i = 0; i < 256; i++) - { - png_ptr->gamma_to_1[i] = (png_byte)(pow((double)i / 255.0, - g) * 255.0 + .5); - } - - - png_ptr->gamma_from_1 = (png_bytep)png_malloc(png_ptr, - (png_uint_32)256); - - if(png_ptr->screen_gamma > 0.000001) - g = 1.0 / png_ptr->screen_gamma; - else - g = png_ptr->gamma; /* probably doing rgb_to_gray */ - - for (i = 0; i < 256; i++) - { - png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0, - g) * 255.0 + .5); - - } - } -#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */ - } - else - { - double g; - int i, j, shift, num; - int sig_bit; - png_uint_32 ig; - if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) - { - sig_bit = (int)png_ptr->sig_bit.red; - if ((int)png_ptr->sig_bit.green > sig_bit) - sig_bit = png_ptr->sig_bit.green; - if ((int)png_ptr->sig_bit.blue > sig_bit) - sig_bit = png_ptr->sig_bit.blue; - } - else - { - sig_bit = (int)png_ptr->sig_bit.gray; - } - - if (sig_bit > 0) - shift = 16 - sig_bit; - else - shift = 0; - - if (png_ptr->transformations & PNG_16_TO_8) - { - if (shift < (16 - PNG_MAX_GAMMA_8)) - shift = (16 - PNG_MAX_GAMMA_8); - } - - if (shift > 8) - shift = 8; - if (shift < 0) - shift = 0; - - png_ptr->gamma_shift = (png_byte)shift; - - num = (1 << (8 - shift)); - - if (png_ptr->screen_gamma > .000001) - g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); - else - g = 1.0; - - png_ptr->gamma_16_table = (png_uint_16pp)png_malloc(png_ptr, - (png_uint_32)(num * png_sizeof (png_uint_16p))); - - if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND)) - { - double fin, fout; - png_uint_32 last, max; - - for (i = 0; i < num; i++) - { - png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr, - (png_uint_32)(256 * png_sizeof (png_uint_16))); - } - - g = 1.0 / g; - last = 0; - for (i = 0; i < 256; i++) - { - fout = ((double)i + 0.5) / 256.0; - fin = pow(fout, g); - max = (png_uint_32)(fin * (double)((png_uint_32)num << 8)); - while (last <= max) - { - png_ptr->gamma_16_table[(int)(last & (0xff >> shift))] - [(int)(last >> (8 - shift))] = (png_uint_16)( - (png_uint_16)i | ((png_uint_16)i << 8)); - last++; - } - } - while (last < ((png_uint_32)num << 8)) - { - png_ptr->gamma_16_table[(int)(last & (0xff >> shift))] - [(int)(last >> (8 - shift))] = (png_uint_16)65535L; - last++; - } - } - else - { - for (i = 0; i < num; i++) - { - png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr, - (png_uint_32)(256 * png_sizeof (png_uint_16))); - - ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4); - for (j = 0; j < 256; j++) - { - png_ptr->gamma_16_table[i][j] = - (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) / - 65535.0, g) * 65535.0 + .5); - } - } - } - -#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ - defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) - if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY)) - { - - g = 1.0 / (png_ptr->gamma); - - png_ptr->gamma_16_to_1 = (png_uint_16pp)png_malloc(png_ptr, - (png_uint_32)(num * png_sizeof (png_uint_16p ))); - - for (i = 0; i < num; i++) - { - png_ptr->gamma_16_to_1[i] = (png_uint_16p)png_malloc(png_ptr, - (png_uint_32)(256 * png_sizeof (png_uint_16))); - - ig = (((png_uint_32)i * - (png_uint_32)png_gamma_shift[shift]) >> 4); - for (j = 0; j < 256; j++) - { - png_ptr->gamma_16_to_1[i][j] = - (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) / - 65535.0, g) * 65535.0 + .5); - } - } - - if(png_ptr->screen_gamma > 0.000001) - g = 1.0 / png_ptr->screen_gamma; - else - g = png_ptr->gamma; /* probably doing rgb_to_gray */ - - png_ptr->gamma_16_from_1 = (png_uint_16pp)png_malloc(png_ptr, - (png_uint_32)(num * png_sizeof (png_uint_16p))); - - for (i = 0; i < num; i++) + for (i = 0; i < row_width; i++, sp++) { - 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); - } + *sp = quantize_lookup[*sp]; } } -#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 */ -#if defined(PNG_MNG_FEATURES_SUPPORTED) -/* undoes intrapixel differencing */ +#ifdef PNG_MNG_FEATURES_SUPPORTED +/* Undoes intrapixel differencing */ void /* PRIVATE */ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) { - png_debug(1, "in png_do_read_intrapixel\n"); + png_debug(1, "in png_do_read_intrapixel"); + if ( -#if defined(PNG_USELESS_TESTS_SUPPORTED) - row != NULL && row_info != NULL && -#endif (row_info->color_type & PNG_COLOR_MASK_COLOR)) { int bytes_per_pixel; png_uint_32 row_width = row_info->width; + if (row_info->bit_depth == 8) { png_bytep rp; @@ -4136,15 +4977,17 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) if (row_info->color_type == PNG_COLOR_TYPE_RGB) bytes_per_pixel = 3; + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) bytes_per_pixel = 4; + else return; for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) { - *(rp) = (png_byte)((256 + *rp + *(rp+1))&0xff); - *(rp+2) = (png_byte)((256 + *(rp+2) + *(rp+1))&0xff); + *(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) @@ -4154,24 +4997,27 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) if (row_info->color_type == PNG_COLOR_TYPE_RGB) bytes_per_pixel = 6; + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) bytes_per_pixel = 8; + else return; for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) { - png_uint_32 s0 = (*(rp ) << 8) | *(rp+1); - png_uint_32 s1 = (*(rp+2) << 8) | *(rp+3); - png_uint_32 s2 = (*(rp+4) << 8) | *(rp+5); - png_uint_32 red = (png_uint_32)((s0+s1+65536L) & 0xffffL); - png_uint_32 blue = (png_uint_32)((s2+s1+65536L) & 0xffffL); - *(rp ) = (png_byte)((red >> 8) & 0xff); - *(rp+1) = (png_byte)(red & 0xff); - *(rp+4) = (png_byte)((blue >> 8) & 0xff); - *(rp+5) = (png_byte)(blue & 0xff); + png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1); + png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3); + png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5); + png_uint_32 red = (s0 + s1 + 65536) & 0xffff; + png_uint_32 blue = (s2 + s1 + 65536) & 0xffff; + *(rp ) = (png_byte)((red >> 8) & 0xff); + *(rp + 1) = (png_byte)(red & 0xff); + *(rp + 4) = (png_byte)((blue >> 8) & 0xff); + *(rp + 5) = (png_byte)(blue & 0xff); } } } } #endif /* PNG_MNG_FEATURES_SUPPORTED */ +#endif /* PNG_READ_SUPPORTED */