/* 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 */ |