| /* pngwtran.c - transforms the data in a row for PNG writers | |
| * | |
| * Last changed in libpng 1.6.0 [February 14, 2013] | |
| * Copyright (c) 1998-2013 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 | |
| */ | |
| #include "pngpriv.h" | |
| #ifdef PNG_WRITE_SUPPORTED | |
| #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED | |
| /* Transform the data according to the user's wishes. The order of | |
| * transformations is significant. | |
| */ | |
| void /* PRIVATE */ | |
| png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info) | |
| { | |
| png_debug(1, "in png_do_write_transformations"); | |
| if (png_ptr == NULL) | |
| return; | |
| #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED | |
| if (png_ptr->transformations & PNG_USER_TRANSFORM) | |
| if (png_ptr->write_user_transform_fn != NULL) | |
| (*(png_ptr->write_user_transform_fn)) /* User write 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 */ | |
| #endif | |
| #ifdef PNG_WRITE_FILLER_SUPPORTED | |
| if (png_ptr->transformations & PNG_FILLER) | |
| png_do_strip_channel(row_info, png_ptr->row_buf + 1, | |
| !(png_ptr->flags & PNG_FLAG_FILLER_AFTER)); | |
| #endif | |
| #ifdef PNG_WRITE_PACKSWAP_SUPPORTED | |
| if (png_ptr->transformations & PNG_PACKSWAP) | |
| png_do_packswap(row_info, png_ptr->row_buf + 1); | |
| #endif | |
| #ifdef PNG_WRITE_PACK_SUPPORTED | |
| if (png_ptr->transformations & PNG_PACK) | |
| png_do_pack(row_info, png_ptr->row_buf + 1, | |
| (png_uint_32)png_ptr->bit_depth); | |
| #endif | |
| #ifdef PNG_WRITE_SWAP_SUPPORTED | |
| if (png_ptr->transformations & PNG_SWAP_BYTES) | |
| png_do_swap(row_info, png_ptr->row_buf + 1); | |
| #endif | |
| #ifdef PNG_WRITE_SHIFT_SUPPORTED | |
| if (png_ptr->transformations & PNG_SHIFT) | |
| png_do_shift(row_info, png_ptr->row_buf + 1, | |
| &(png_ptr->shift)); | |
| #endif | |
| #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED | |
| if (png_ptr->transformations & PNG_SWAP_ALPHA) | |
| png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1); | |
| #endif | |
| #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED | |
| if (png_ptr->transformations & PNG_INVERT_ALPHA) | |
| png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1); | |
| #endif | |
| #ifdef PNG_WRITE_BGR_SUPPORTED | |
| if (png_ptr->transformations & PNG_BGR) | |
| png_do_bgr(row_info, png_ptr->row_buf + 1); | |
| #endif | |
| #ifdef PNG_WRITE_INVERT_SUPPORTED | |
| if (png_ptr->transformations & PNG_INVERT_MONO) | |
| png_do_invert(row_info, png_ptr->row_buf + 1); | |
| #endif | |
| } | |
| #ifdef PNG_WRITE_PACK_SUPPORTED | |
| /* Pack pixels into bytes. Pass the true bit depth in bit_depth. The | |
| * row_info bit depth should be 8 (one pixel per byte). The channels | |
| * should be 1 (this only happens on grayscale and paletted images). | |
| */ | |
| void /* PRIVATE */ | |
| png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth) | |
| { | |
| png_debug(1, "in png_do_pack"); | |
| if (row_info->bit_depth == 8 && | |
| row_info->channels == 1) | |
| { | |
| switch ((int)bit_depth) | |
| { | |
| case 1: | |
| { | |
| png_bytep sp, dp; | |
| int mask, v; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| sp = row; | |
| dp = row; | |
| mask = 0x80; | |
| v = 0; | |
| for (i = 0; i < row_width; i++) | |
| { | |
| if (*sp != 0) | |
| v |= mask; | |
| sp++; | |
| if (mask > 1) | |
| mask >>= 1; | |
| else | |
| { | |
| mask = 0x80; | |
| *dp = (png_byte)v; | |
| dp++; | |
| v = 0; | |
| } | |
| } | |
| if (mask != 0x80) | |
| *dp = (png_byte)v; | |
| break; | |
| } | |
| case 2: | |
| { | |
| png_bytep sp, dp; | |
| int shift, v; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| sp = row; | |
| dp = row; | |
| shift = 6; | |
| v = 0; | |
| for (i = 0; i < row_width; i++) | |
| { | |
| png_byte value; | |
| value = (png_byte)(*sp & 0x03); | |
| v |= (value << shift); | |
| if (shift == 0) | |
| { | |
| shift = 6; | |
| *dp = (png_byte)v; | |
| dp++; | |
| v = 0; | |
| } | |
| else | |
| shift -= 2; | |
| sp++; | |
| } | |
| if (shift != 6) | |
| *dp = (png_byte)v; | |
| break; | |
| } | |
| case 4: | |
| { | |
| png_bytep sp, dp; | |
| int shift, v; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| sp = row; | |
| dp = row; | |
| shift = 4; | |
| v = 0; | |
| for (i = 0; i < row_width; i++) | |
| { | |
| png_byte value; | |
| value = (png_byte)(*sp & 0x0f); | |
| v |= (value << shift); | |
| if (shift == 0) | |
| { | |
| shift = 4; | |
| *dp = (png_byte)v; | |
| dp++; | |
| v = 0; | |
| } | |
| else | |
| shift -= 4; | |
| sp++; | |
| } | |
| if (shift != 4) | |
| *dp = (png_byte)v; | |
| break; | |
| } | |
| default: | |
| break; | |
| } | |
| row_info->bit_depth = (png_byte)bit_depth; | |
| row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels); | |
| row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, | |
| row_info->width); | |
| } | |
| } | |
| #endif | |
| #ifdef PNG_WRITE_SHIFT_SUPPORTED | |
| /* Shift pixel values to take advantage of whole range. Pass the | |
| * true number of bits in bit_depth. The row should be packed | |
| * according to row_info->bit_depth. Thus, if you had a row of | |
| * bit depth 4, but the pixels only had values from 0 to 7, you | |
| * would pass 3 as bit_depth, and this routine would translate the | |
| * data to 0 to 15. | |
| */ | |
| void /* PRIVATE */ | |
| png_do_shift(png_row_infop row_info, png_bytep row, | |
| png_const_color_8p bit_depth) | |
| { | |
| png_debug(1, "in png_do_shift"); | |
| if (row_info->color_type != PNG_COLOR_TYPE_PALETTE) | |
| { | |
| int shift_start[4], shift_dec[4]; | |
| int channels = 0; | |
| if (row_info->color_type & PNG_COLOR_MASK_COLOR) | |
| { | |
| shift_start[channels] = row_info->bit_depth - bit_depth->red; | |
| shift_dec[channels] = bit_depth->red; | |
| channels++; | |
| shift_start[channels] = row_info->bit_depth - bit_depth->green; | |
| shift_dec[channels] = bit_depth->green; | |
| channels++; | |
| shift_start[channels] = row_info->bit_depth - bit_depth->blue; | |
| shift_dec[channels] = bit_depth->blue; | |
| channels++; | |
| } | |
| else | |
| { | |
| shift_start[channels] = row_info->bit_depth - bit_depth->gray; | |
| shift_dec[channels] = bit_depth->gray; | |
| channels++; | |
| } | |
| if (row_info->color_type & PNG_COLOR_MASK_ALPHA) | |
| { | |
| shift_start[channels] = row_info->bit_depth - bit_depth->alpha; | |
| shift_dec[channels] = bit_depth->alpha; | |
| channels++; | |
| } | |
| /* With low row depths, could only be grayscale, so one channel */ | |
| if (row_info->bit_depth < 8) | |
| { | |
| png_bytep bp = row; | |
| png_size_t i; | |
| unsigned int mask; | |
| png_size_t row_bytes = row_info->rowbytes; | |
| if (bit_depth->gray == 1 && row_info->bit_depth == 2) | |
| mask = 0x55; | |
| else if (row_info->bit_depth == 4 && bit_depth->gray == 3) | |
| mask = 0x11; | |
| else | |
| mask = 0xff; | |
| for (i = 0; i < row_bytes; i++, bp++) | |
| { | |
| int j; | |
| unsigned int v, out; | |
| v = *bp; | |
| out = 0; | |
| for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0]) | |
| { | |
| if (j > 0) | |
| out |= v << j; | |
| else | |
| out |= (v >> (-j)) & mask; | |
| } | |
| *bp = (png_byte)(out & 0xff); | |
| } | |
| } | |
| else if (row_info->bit_depth == 8) | |
| { | |
| png_bytep bp = row; | |
| png_uint_32 i; | |
| png_uint_32 istop = channels * row_info->width; | |
| for (i = 0; i < istop; i++, bp++) | |
| { | |
| const unsigned int c = i%channels; | |
| int j; | |
| unsigned int v, out; | |
| v = *bp; | |
| out = 0; | |
| for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) | |
| { | |
| if (j > 0) | |
| out |= v << j; | |
| else | |
| out |= v >> (-j); | |
| } | |
| *bp = (png_byte)(out & 0xff); | |
| } | |
| } | |
| else | |
| { | |
| png_bytep bp; | |
| png_uint_32 i; | |
| png_uint_32 istop = channels * row_info->width; | |
| for (bp = row, i = 0; i < istop; i++) | |
| { | |
| const unsigned int c = i%channels; | |
| int j; | |
| unsigned int value, v; | |
| v = png_get_uint_16(bp); | |
| value = 0; | |
| for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) | |
| { | |
| if (j > 0) | |
| value |= v << j; | |
| else | |
| value |= v >> (-j); | |
| } | |
| *bp++ = (png_byte)((value >> 8) & 0xff); | |
| *bp++ = (png_byte)(value & 0xff); | |
| } | |
| } | |
| } | |
| } | |
| #endif | |
| #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED | |
| void /* PRIVATE */ | |
| png_do_write_swap_alpha(png_row_infop row_info, png_bytep row) | |
| { | |
| png_debug(1, "in png_do_write_swap_alpha"); | |
| { | |
| if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
| { | |
| if (row_info->bit_depth == 8) | |
| { | |
| /* This converts from ARGB to RGBA */ | |
| png_bytep sp, dp; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| for (i = 0, sp = dp = row; i < row_width; i++) | |
| { | |
| png_byte save = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = save; | |
| } | |
| } | |
| #ifdef PNG_WRITE_16BIT_SUPPORTED | |
| else | |
| { | |
| /* This converts from AARRGGBB to RRGGBBAA */ | |
| png_bytep sp, dp; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| for (i = 0, sp = dp = row; i < row_width; i++) | |
| { | |
| png_byte save[2]; | |
| save[0] = *(sp++); | |
| save[1] = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = save[0]; | |
| *(dp++) = save[1]; | |
| } | |
| } | |
| #endif /* PNG_WRITE_16BIT_SUPPORTED */ | |
| } | |
| else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) | |
| { | |
| if (row_info->bit_depth == 8) | |
| { | |
| /* This converts from AG to GA */ | |
| png_bytep sp, dp; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| for (i = 0, sp = dp = row; i < row_width; i++) | |
| { | |
| png_byte save = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = save; | |
| } | |
| } | |
| #ifdef PNG_WRITE_16BIT_SUPPORTED | |
| else | |
| { | |
| /* This converts from AAGG to GGAA */ | |
| png_bytep sp, dp; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| for (i = 0, sp = dp = row; i < row_width; i++) | |
| { | |
| png_byte save[2]; | |
| save[0] = *(sp++); | |
| save[1] = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = save[0]; | |
| *(dp++) = save[1]; | |
| } | |
| } | |
| #endif /* PNG_WRITE_16BIT_SUPPORTED */ | |
| } | |
| } | |
| } | |
| #endif | |
| #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED | |
| void /* PRIVATE */ | |
| png_do_write_invert_alpha(png_row_infop row_info, png_bytep row) | |
| { | |
| png_debug(1, "in png_do_write_invert_alpha"); | |
| { | |
| if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
| { | |
| if (row_info->bit_depth == 8) | |
| { | |
| /* This inverts the alpha channel in RGBA */ | |
| png_bytep sp, dp; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| for (i = 0, sp = dp = row; i < row_width; i++) | |
| { | |
| /* Does nothing | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| */ | |
| sp+=3; dp = sp; | |
| *(dp++) = (png_byte)(255 - *(sp++)); | |
| } | |
| } | |
| #ifdef PNG_WRITE_16BIT_SUPPORTED | |
| else | |
| { | |
| /* This inverts the alpha channel in RRGGBBAA */ | |
| png_bytep sp, dp; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| for (i = 0, sp = dp = row; i < row_width; i++) | |
| { | |
| /* Does nothing | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| */ | |
| sp+=6; dp = sp; | |
| *(dp++) = (png_byte)(255 - *(sp++)); | |
| *(dp++) = (png_byte)(255 - *(sp++)); | |
| } | |
| } | |
| #endif /* PNG_WRITE_16BIT_SUPPORTED */ | |
| } | |
| else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) | |
| { | |
| if (row_info->bit_depth == 8) | |
| { | |
| /* This inverts the alpha channel in GA */ | |
| png_bytep sp, dp; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| for (i = 0, sp = dp = row; i < row_width; i++) | |
| { | |
| *(dp++) = *(sp++); | |
| *(dp++) = (png_byte)(255 - *(sp++)); | |
| } | |
| } | |
| #ifdef PNG_WRITE_16BIT_SUPPORTED | |
| else | |
| { | |
| /* This inverts the alpha channel in GGAA */ | |
| png_bytep sp, dp; | |
| png_uint_32 i; | |
| png_uint_32 row_width = row_info->width; | |
| for (i = 0, sp = dp = row; i < row_width; i++) | |
| { | |
| /* Does nothing | |
| *(dp++) = *(sp++); | |
| *(dp++) = *(sp++); | |
| */ | |
| sp+=2; dp = sp; | |
| *(dp++) = (png_byte)(255 - *(sp++)); | |
| *(dp++) = (png_byte)(255 - *(sp++)); | |
| } | |
| } | |
| #endif /* PNG_WRITE_16BIT_SUPPORTED */ | |
| } | |
| } | |
| } | |
| #endif | |
| #endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */ | |
| #ifdef PNG_MNG_FEATURES_SUPPORTED | |
| /* Undoes intrapixel differencing */ | |
| void /* PRIVATE */ | |
| png_do_write_intrapixel(png_row_infop row_info, png_bytep row) | |
| { | |
| png_debug(1, "in png_do_write_intrapixel"); | |
| if ((row_info->color_type & PNG_COLOR_MASK_COLOR)) | |
| { | |
| int bytes_per_pixel; | |
| png_uint_32 row_width = row_info->width; | |
| if (row_info->bit_depth == 8) | |
| { | |
| png_bytep rp; | |
| png_uint_32 i; | |
| if (row_info->color_type == PNG_COLOR_TYPE_RGB) | |
| bytes_per_pixel = 3; | |
| else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
| bytes_per_pixel = 4; | |
| else | |
| return; | |
| for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) | |
| { | |
| *(rp) = (png_byte)((*rp - *(rp + 1)) & 0xff); | |
| *(rp + 2) = (png_byte)((*(rp + 2) - *(rp + 1)) & 0xff); | |
| } | |
| } | |
| #ifdef PNG_WRITE_16BIT_SUPPORTED | |
| else if (row_info->bit_depth == 16) | |
| { | |
| png_bytep rp; | |
| png_uint_32 i; | |
| if (row_info->color_type == PNG_COLOR_TYPE_RGB) | |
| bytes_per_pixel = 6; | |
| else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
| bytes_per_pixel = 8; | |
| else | |
| return; | |
| for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) | |
| { | |
| png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1); | |
| png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3); | |
| png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5); | |
| png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL); | |
| png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL); | |
| *(rp ) = (png_byte)((red >> 8) & 0xff); | |
| *(rp + 1) = (png_byte)(red & 0xff); | |
| *(rp + 4) = (png_byte)((blue >> 8) & 0xff); | |
| *(rp + 5) = (png_byte)(blue & 0xff); | |
| } | |
| } | |
| #endif /* PNG_WRITE_16BIT_SUPPORTED */ | |
| } | |
| } | |
| #endif /* PNG_MNG_FEATURES_SUPPORTED */ | |
| #endif /* PNG_WRITE_SUPPORTED */ |