| |
| /* pngwtran.c - transforms the data in a row for PNG writers |
| * |
| * Copyright (c) 2018 Cosmin Truta |
| * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson |
| * Copyright (c) 1996-1997 Andreas Dilger |
| * 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 |
| |
| #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). |
| */ |
| static void |
| 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; |
| unsigned int shift; |
| int 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; |
| unsigned int shift; |
| int 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. |
| */ |
| static void |
| 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]; |
| unsigned int channels = 0; |
| |
| if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0) |
| { |
| 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) != 0) |
| { |
| 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; |
| size_t i; |
| unsigned int mask; |
| 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++) |
| { |
| 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++) |
| { |
| 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 |
| static void |
| 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 /* WRITE_16BIT */ |
| } |
| |
| 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 /* WRITE_16BIT */ |
| } |
| } |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED |
| static void |
| 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 /* WRITE_16BIT */ |
| } |
| |
| 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 /* WRITE_16BIT */ |
| } |
| } |
| } |
| #endif |
| |
| /* 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) != 0) |
| 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 */ |
| /* 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) != 0) |
| 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) != 0) |
| png_do_packswap(row_info, png_ptr->row_buf + 1); |
| #endif |
| |
| #ifdef PNG_WRITE_PACK_SUPPORTED |
| if ((png_ptr->transformations & PNG_PACK) != 0) |
| png_do_pack(row_info, png_ptr->row_buf + 1, |
| (png_uint_32)png_ptr->bit_depth); |
| #endif |
| |
| #ifdef PNG_WRITE_SWAP_SUPPORTED |
| # ifdef PNG_16BIT_SUPPORTED |
| if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0) |
| png_do_swap(row_info, png_ptr->row_buf + 1); |
| # endif |
| #endif |
| |
| #ifdef PNG_WRITE_SHIFT_SUPPORTED |
| if ((png_ptr->transformations & PNG_SHIFT) != 0) |
| 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) != 0) |
| 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) != 0) |
| png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1); |
| #endif |
| |
| #ifdef PNG_WRITE_BGR_SUPPORTED |
| if ((png_ptr->transformations & PNG_BGR) != 0) |
| png_do_bgr(row_info, png_ptr->row_buf + 1); |
| #endif |
| |
| #ifdef PNG_WRITE_INVERT_SUPPORTED |
| if ((png_ptr->transformations & PNG_INVERT_MONO) != 0) |
| png_do_invert(row_info, png_ptr->row_buf + 1); |
| #endif |
| } |
| #endif /* WRITE_TRANSFORMS */ |
| #endif /* WRITE */ |
