diff options
Diffstat (limited to 'pngrtran.c')
| -rw-r--r-- | pngrtran.c | 724 |
1 files changed, 301 insertions, 423 deletions
diff --git a/pngrtran.c b/pngrtran.c index d67e25d9d..f0c016478 100644 --- a/pngrtran.c +++ b/pngrtran.c @@ -1,8 +1,8 @@ /* pngrtran.c - transforms the data in a row for PNG readers * - * Last changed in libpng 1.6.8 [December 19, 2013] - * Copyright (c) 1998-2013 Glenn Randers-Pehrson + * Last changed in libpng 1.6.9 [February 6, 2014] + * Copyright (c) 1998-2014 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.) * @@ -1134,7 +1134,7 @@ png_init_palette_transformations(png_structrp png_ptr) 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 + * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA * and ENCODE_ALPHA are irrelevant. */ png_ptr->transformations &= ~PNG_ENCODE_ALPHA; @@ -1199,7 +1199,7 @@ png_init_rgb_transformations(png_structrp png_ptr) 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 + * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA * and ENCODE_ALPHA are irrelevant. */ # ifdef PNG_READ_ALPHA_MODE_SUPPORTED @@ -2123,303 +2123,6 @@ defined(PNG_READ_USER_TRANSFORM_SUPPORTED) #endif } -/* Transform the row. The order of transformations is significant, - * and is very touchy. If you add a transformation, take care to - * decide how it fits in with the other transformations here. - */ -void /* PRIVATE */ -png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info) -{ - png_debug(1, "in png_do_read_transformations"); - - if (png_ptr->row_buf == NULL) - { - /* 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"); - } - - /* 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 1.6 the new flag is set only for - * all transformations, however in practice the ROW_INIT always gets done on - * demand, if necessary. - */ - 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 (row_info->color_type == PNG_COLOR_TYPE_PALETTE) - { - 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_ptr->transformations & PNG_EXPAND_tRNS)) - png_do_expand(row_info, png_ptr->row_buf + 1, - &(png_ptr->trans_color)); - - else - png_do_expand(row_info, png_ptr->row_buf + 1, - NULL); - } - } -#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 - -#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, row_info, - png_ptr->row_buf + 1); - - if (rgb_error) - { - png_ptr->rgb_to_gray_status=1; - if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == - PNG_RGB_TO_GRAY_WARN) - png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel"); - - if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == - PNG_RGB_TO_GRAY_ERR) - png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel"); - } - } -#endif - -/* From Andreas Dilger e-mail to png-implement, 26 March 1998: - * - * In most cases, the "simple transparency" should be done prior to doing - * gray-to-RGB, or you will have to test 3x as many bytes to check if a - * pixel is transparent. You would also need to make sure that the - * transparency information is upgraded to RGB. - * - * To summarize, the current flow is: - * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite - * with background "in place" if transparent, - * convert to RGB if necessary - * - Gray + alpha -> composite with gray background and remove alpha bytes, - * convert to RGB if necessary - * - * To support RGB backgrounds for gray images we need: - * - Gray + simple transparency -> convert to RGB + simple transparency, - * compare 3 or 6 bytes and composite with - * background "in place" if transparent - * (3x compare/pixel compared to doing - * composite with gray bkgrnd) - * - Gray + alpha -> convert to RGB + alpha, composite with background and - * remove alpha bytes (3x float - * operations/pixel compared with composite - * on gray background) - * - * Greg's change will do this. The reason it wasn't done before is for - * performance, as this increases the per-pixel operations. If we would check - * in advance if the background was gray or RGB, and position the gray-to-RGB - * transform appropriately, then it would save a lot of work/time. - */ - -#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED - /* If gray -> RGB, do so now only if background is non-gray; else do later - * for performance reasons - */ - if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && - !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) - png_do_gray_to_rgb(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 - /* 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 - -#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 - -#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 - -#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(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_QUANTIZE_SUPPORTED - if (png_ptr->transformations & PNG_QUANTIZE) - { - 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 - -#ifdef PNG_READ_INVERT_SUPPORTED - if (png_ptr->transformations & PNG_INVERT_MONO) - png_do_invert(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_SHIFT_SUPPORTED - if (png_ptr->transformations & PNG_SHIFT) - png_do_unshift(row_info, png_ptr->row_buf + 1, - &(png_ptr->shift)); -#endif - -#ifdef PNG_READ_PACK_SUPPORTED - if (png_ptr->transformations & PNG_PACK) - png_do_unpack(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED - /* Added at libpng-1.5.10 */ - if (row_info->color_type == PNG_COLOR_TYPE_PALETTE && - png_ptr->num_palette_max >= 0) - png_do_check_palette_indexes(png_ptr, row_info); -#endif - -#ifdef PNG_READ_BGR_SUPPORTED - if (png_ptr->transformations & PNG_BGR) - png_do_bgr(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_PACKSWAP_SUPPORTED - if (png_ptr->transformations & PNG_PACKSWAP) - png_do_packswap(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_FILLER_SUPPORTED - if (png_ptr->transformations & PNG_FILLER) - png_do_read_filler(row_info, png_ptr->row_buf + 1, - (png_uint_32)png_ptr->filler, png_ptr->flags); -#endif - -#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED - if (png_ptr->transformations & PNG_INVERT_ALPHA) - png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED - if (png_ptr->transformations & PNG_SWAP_ALPHA) - png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1); -#endif - -#ifdef PNG_READ_16BIT_SUPPORTED -#ifdef PNG_READ_SWAP_SUPPORTED - if (png_ptr->transformations & PNG_SWAP_BYTES) - png_do_swap(row_info, png_ptr->row_buf + 1); -#endif -#endif - -#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED - if (png_ptr->transformations & PNG_USER_TRANSFORM) - { - if (png_ptr->read_user_transform_fn != NULL) - (*(png_ptr->read_user_transform_fn)) /* User read transform function */ - (png_ptr, /* png_ptr */ - 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 - 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 -} - #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 @@ -2427,7 +2130,7 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info) * the numbers 0 or 1. If you would rather they contain 0 and 255, use * png_do_shift() after this. */ -void /* PRIVATE */ +static void png_do_unpack(png_row_infop row_info, png_bytep row) { png_debug(1, "in png_do_unpack"); @@ -2525,7 +2228,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row) * a row of bit depth 8, but only 5 are significant, this will shift * the values back to 0 through 31. */ -void /* PRIVATE */ +static void png_do_unshift(png_row_infop row_info, png_bytep row, png_const_color_8p sig_bits) { @@ -2664,7 +2367,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED /* Scale rows of bit depth 16 down to 8 accurately */ -void /* PRIVATE */ +static void png_do_scale_16_to_8(png_row_infop row_info, png_bytep row) { png_debug(1, "in png_do_scale_16_to_8"); @@ -2722,7 +2425,7 @@ png_do_scale_16_to_8(png_row_infop row_info, png_bytep row) #endif #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED -void /* PRIVATE */ +static void /* Simply discard the low byte. This was the default behavior prior * to libpng-1.5.4. */ @@ -2750,7 +2453,7 @@ png_do_chop(png_row_infop row_info, png_bytep row) #endif #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED -void /* PRIVATE */ +static void png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) { png_debug(1, "in png_do_read_swap_alpha"); @@ -2847,7 +2550,7 @@ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) #endif #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED -void /* PRIVATE */ +static void png_do_read_invert_alpha(png_row_infop row_info, png_bytep row) { png_uint_32 row_width; @@ -2949,7 +2652,7 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row) #ifdef PNG_READ_FILLER_SUPPORTED /* Add filler channel if we have RGB color */ -void /* PRIVATE */ +static void png_do_read_filler(png_row_infop row_info, png_bytep row, png_uint_32 filler, png_uint_32 flags) { @@ -3136,7 +2839,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED /* Expand grayscale files to RGB, with or without alpha */ -void /* PRIVATE */ +static void png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) { png_uint_32 i; @@ -3275,7 +2978,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) * calculated to make the sum 32768. This will result in different rounding * to that used above. */ -int /* PRIVATE */ +static int png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row) { @@ -3469,73 +3172,14 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row) 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. This API is not used internally. - */ -void PNGAPI -png_build_grayscale_palette(int bit_depth, png_colorp palette) -{ - int num_palette; - int color_inc; - int i; - int v; - - png_debug(1, "in png_do_build_grayscale_palette"); - - if (palette == NULL) - return; - - switch (bit_depth) - { - case 1: - num_palette = 2; - color_inc = 0xff; - break; - - case 2: - num_palette = 4; - color_inc = 0x55; - break; - - case 4: - num_palette = 16; - color_inc = 0x11; - break; - - case 8: - num_palette = 256; - color_inc = 1; - break; - - default: - num_palette = 0; - color_inc = 0; - break; - } - - for (i = 0, v = 0; i < num_palette; i++, v += color_inc) - { - palette[i].red = (png_byte)v; - palette[i].green = (png_byte)v; - palette[i].blue = (png_byte)v; - } -} -#endif - -#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 */ +static void png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr) { #ifdef PNG_READ_GAMMA_SUPPORTED @@ -4275,7 +3919,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr) * is 16, use gamma_16_table and gamma_shift. Build these with * build_gamma_table(). */ -void /* PRIVATE */ +static void png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr) { png_const_bytep gamma_table = png_ptr->gamma_table; @@ -4476,7 +4120,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr) * linear.) Called only with color types that have an alpha channel. Needs the * from_1 tables. */ -void /* PRIVATE */ +static void png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr) { png_uint_32 row_width = row_info->width; @@ -4542,7 +4186,7 @@ png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr) /* Expands a palette row to an RGB or RGBA row depending * upon whether you supply trans and num_trans. */ -void /* PRIVATE */ +static void png_do_expand_palette(png_row_infop row_info, png_bytep row, png_const_colorp palette, png_const_bytep trans_alpha, int num_trans) { @@ -4695,7 +4339,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, /* 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 */ +static void png_do_expand(png_row_infop row_info, png_bytep row, png_const_color_16p trans_color) { @@ -4925,7 +4569,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, /* 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 */ +static void png_do_expand_16(png_row_infop row_info, png_bytep row) { if (row_info->bit_depth == 8 && @@ -4953,7 +4597,7 @@ png_do_expand_16(png_row_infop row_info, png_bytep row) #endif #ifdef PNG_READ_QUANTIZE_SUPPORTED -void /* PRIVATE */ +static void png_do_quantize(png_row_infop row_info, png_bytep row, png_const_bytep palette_lookup, png_const_bytep quantize_lookup) { @@ -5045,69 +4689,303 @@ png_do_quantize(png_row_infop row_info, png_bytep row, } } #endif /* PNG_READ_QUANTIZE_SUPPORTED */ -#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ -#ifdef PNG_MNG_FEATURES_SUPPORTED -/* Undoes intrapixel differencing */ +/* Transform the row. The order of transformations is significant, + * and is very touchy. If you add a transformation, take care to + * decide how it fits in with the other transformations here. + */ void /* PRIVATE */ -png_do_read_intrapixel(png_row_infop row_info, png_bytep row) +png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info) { - png_debug(1, "in png_do_read_intrapixel"); + png_debug(1, "in png_do_read_transformations"); - if ( - (row_info->color_type & PNG_COLOR_MASK_COLOR)) + if (png_ptr->row_buf == NULL) { - int bytes_per_pixel; - png_uint_32 row_width = row_info->width; + /* 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"); + } - if (row_info->bit_depth == 8) - { - png_bytep rp; - png_uint_32 i; + /* 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 1.6 the new flag is set only for + * all transformations, however in practice the ROW_INIT always gets done on + * demand, if necessary. + */ + 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"); + } - if (row_info->color_type == PNG_COLOR_TYPE_RGB) - bytes_per_pixel = 3; +#ifdef PNG_READ_EXPAND_SUPPORTED + if (png_ptr->transformations & PNG_EXPAND) + { + if (row_info->color_type == PNG_COLOR_TYPE_PALETTE) + { + png_do_expand_palette(row_info, png_ptr->row_buf + 1, + png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans); + } - else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) - bytes_per_pixel = 4; + else + { + 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 - 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); - } + png_do_expand(row_info, png_ptr->row_buf + 1, + NULL); } - else if (row_info->bit_depth == 16) - { - png_bytep rp; - png_uint_32 i; + } +#endif - if (row_info->color_type == PNG_COLOR_TYPE_RGB) - bytes_per_pixel = 6; +#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 - else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) - bytes_per_pixel = 8; +#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, row_info, + png_ptr->row_buf + 1); - else - return; + if (rgb_error) + { + png_ptr->rgb_to_gray_status=1; + if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == + PNG_RGB_TO_GRAY_WARN) + png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel"); - 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 = (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); - } + if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == + PNG_RGB_TO_GRAY_ERR) + png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel"); } } +#endif + +/* From Andreas Dilger e-mail to png-implement, 26 March 1998: + * + * In most cases, the "simple transparency" should be done prior to doing + * gray-to-RGB, or you will have to test 3x as many bytes to check if a + * pixel is transparent. You would also need to make sure that the + * transparency information is upgraded to RGB. + * + * To summarize, the current flow is: + * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite + * with background "in place" if transparent, + * convert to RGB if necessary + * - Gray + alpha -> composite with gray background and remove alpha bytes, + * convert to RGB if necessary + * + * To support RGB backgrounds for gray images we need: + * - Gray + simple transparency -> convert to RGB + simple transparency, + * compare 3 or 6 bytes and composite with + * background "in place" if transparent + * (3x compare/pixel compared to doing + * composite with gray bkgrnd) + * - Gray + alpha -> convert to RGB + alpha, composite with background and + * remove alpha bytes (3x float + * operations/pixel compared with composite + * on gray background) + * + * Greg's change will do this. The reason it wasn't done before is for + * performance, as this increases the per-pixel operations. If we would check + * in advance if the background was gray or RGB, and position the gray-to-RGB + * transform appropriately, then it would save a lot of work/time. + */ + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + /* If gray -> RGB, do so now only if background is non-gray; else do later + * for performance reasons + */ + if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && + !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) + png_do_gray_to_rgb(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 + /* 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 + +#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 + +#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 + +#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(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_QUANTIZE_SUPPORTED + if (png_ptr->transformations & PNG_QUANTIZE) + { + 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 + +#ifdef PNG_READ_INVERT_SUPPORTED + if (png_ptr->transformations & PNG_INVERT_MONO) + png_do_invert(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_SHIFT_SUPPORTED + if (png_ptr->transformations & PNG_SHIFT) + png_do_unshift(row_info, png_ptr->row_buf + 1, + &(png_ptr->shift)); +#endif + +#ifdef PNG_READ_PACK_SUPPORTED + if (png_ptr->transformations & PNG_PACK) + png_do_unpack(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED + /* Added at libpng-1.5.10 */ + if (row_info->color_type == PNG_COLOR_TYPE_PALETTE && + png_ptr->num_palette_max >= 0) + png_do_check_palette_indexes(png_ptr, row_info); +#endif + +#ifdef PNG_READ_BGR_SUPPORTED + if (png_ptr->transformations & PNG_BGR) + png_do_bgr(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if (png_ptr->transformations & PNG_PACKSWAP) + png_do_packswap(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_FILLER_SUPPORTED + if (png_ptr->transformations & PNG_FILLER) + png_do_read_filler(row_info, png_ptr->row_buf + 1, + (png_uint_32)png_ptr->filler, png_ptr->flags); +#endif + +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED + if (png_ptr->transformations & PNG_INVERT_ALPHA) + png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED + if (png_ptr->transformations & PNG_SWAP_ALPHA) + png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_16BIT_SUPPORTED +#ifdef PNG_READ_SWAP_SUPPORTED + if (png_ptr->transformations & PNG_SWAP_BYTES) + png_do_swap(row_info, png_ptr->row_buf + 1); +#endif +#endif + +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED + if (png_ptr->transformations & PNG_USER_TRANSFORM) + { + if (png_ptr->read_user_transform_fn != NULL) + (*(png_ptr->read_user_transform_fn)) /* User read transform function */ + (png_ptr, /* png_ptr */ + 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 + 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 } -#endif /* PNG_MNG_FEATURES_SUPPORTED */ + +#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ #endif /* PNG_READ_SUPPORTED */ |