/* pngtrans.c - transforms the data in a row (used by both readers and writers) | |
* | |
* Last changed in libpng 1.6.2 [April 25, 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" | |
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) | |
#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) | |
/* Turn on BGR-to-RGB mapping */ | |
void PNGAPI | |
png_set_bgr(png_structrp png_ptr) | |
{ | |
png_debug(1, "in png_set_bgr"); | |
if (png_ptr == NULL) | |
return; | |
png_ptr->transformations |= PNG_BGR; | |
} | |
#endif | |
#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) | |
/* Turn on 16 bit byte swapping */ | |
void PNGAPI | |
png_set_swap(png_structrp png_ptr) | |
{ | |
png_debug(1, "in png_set_swap"); | |
if (png_ptr == NULL) | |
return; | |
if (png_ptr->bit_depth == 16) | |
png_ptr->transformations |= PNG_SWAP_BYTES; | |
} | |
#endif | |
#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED) | |
/* Turn on pixel packing */ | |
void PNGAPI | |
png_set_packing(png_structrp png_ptr) | |
{ | |
png_debug(1, "in png_set_packing"); | |
if (png_ptr == NULL) | |
return; | |
if (png_ptr->bit_depth < 8) | |
{ | |
png_ptr->transformations |= PNG_PACK; | |
png_ptr->usr_bit_depth = 8; | |
} | |
} | |
#endif | |
#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED) | |
/* Turn on packed pixel swapping */ | |
void PNGAPI | |
png_set_packswap(png_structrp png_ptr) | |
{ | |
png_debug(1, "in png_set_packswap"); | |
if (png_ptr == NULL) | |
return; | |
if (png_ptr->bit_depth < 8) | |
png_ptr->transformations |= PNG_PACKSWAP; | |
} | |
#endif | |
#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED) | |
void PNGAPI | |
png_set_shift(png_structrp png_ptr, png_const_color_8p true_bits) | |
{ | |
png_debug(1, "in png_set_shift"); | |
if (png_ptr == NULL) | |
return; | |
png_ptr->transformations |= PNG_SHIFT; | |
png_ptr->shift = *true_bits; | |
} | |
#endif | |
#if defined(PNG_READ_INTERLACING_SUPPORTED) || \ | |
defined(PNG_WRITE_INTERLACING_SUPPORTED) | |
int PNGAPI | |
png_set_interlace_handling(png_structrp png_ptr) | |
{ | |
png_debug(1, "in png_set_interlace handling"); | |
if (png_ptr && png_ptr->interlaced) | |
{ | |
png_ptr->transformations |= PNG_INTERLACE; | |
return (7); | |
} | |
return (1); | |
} | |
#endif | |
#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED) | |
/* Add a filler byte on read, or remove a filler or alpha byte on write. | |
* The filler type has changed in v0.95 to allow future 2-byte fillers | |
* for 48-bit input data, as well as to avoid problems with some compilers | |
* that don't like bytes as parameters. | |
*/ | |
void PNGAPI | |
png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc) | |
{ | |
png_debug(1, "in png_set_filler"); | |
if (png_ptr == NULL) | |
return; | |
/* In libpng 1.6 it is possible to determine whether this is a read or write | |
* operation and therefore to do more checking here for a valid call. | |
*/ | |
if (png_ptr->mode & PNG_IS_READ_STRUCT) | |
{ | |
# ifdef PNG_READ_FILLER_SUPPORTED | |
/* On read png_set_filler is always valid, regardless of the base PNG | |
* format, because other transformations can give a format where the | |
* filler code can execute (basically an 8 or 16-bit component RGB or G | |
* format.) | |
* | |
* NOTE: usr_channels is not used by the read code! (This has led to | |
* confusion in the past.) The filler is only used in the read code. | |
*/ | |
png_ptr->filler = (png_uint_16)filler; | |
# else | |
png_app_error(png_ptr, "png_set_filler not supported on read"); | |
PNG_UNUSED(filler) /* not used in the write case */ | |
return; | |
# endif | |
} | |
else /* write */ | |
{ | |
# ifdef PNG_WRITE_FILLER_SUPPORTED | |
/* On write the usr_channels parameter must be set correctly at the | |
* start to record the number of channels in the app-supplied data. | |
*/ | |
switch (png_ptr->color_type) | |
{ | |
case PNG_COLOR_TYPE_RGB: | |
png_ptr->usr_channels = 4; | |
break; | |
case PNG_COLOR_TYPE_GRAY: | |
if (png_ptr->bit_depth >= 8) | |
{ | |
png_ptr->usr_channels = 2; | |
break; | |
} | |
else | |
{ | |
/* There simply isn't any code in libpng to strip out bits | |
* from bytes when the components are less than a byte in | |
* size! | |
*/ | |
png_app_error(png_ptr, | |
"png_set_filler is invalid for low bit depth gray output"); | |
return; | |
} | |
default: | |
png_app_error(png_ptr, | |
"png_set_filler: inappropriate color type"); | |
return; | |
} | |
# else | |
png_app_error(png_ptr, "png_set_filler not supported on write"); | |
return; | |
# endif | |
} | |
/* Here on success - libpng supports the operation, set the transformation | |
* and the flag to say where the filler channel is. | |
*/ | |
png_ptr->transformations |= PNG_FILLER; | |
if (filler_loc == PNG_FILLER_AFTER) | |
png_ptr->flags |= PNG_FLAG_FILLER_AFTER; | |
else | |
png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER; | |
} | |
/* Added to libpng-1.2.7 */ | |
void PNGAPI | |
png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc) | |
{ | |
png_debug(1, "in png_set_add_alpha"); | |
if (png_ptr == NULL) | |
return; | |
png_set_filler(png_ptr, filler, filler_loc); | |
/* The above may fail to do anything. */ | |
if (png_ptr->transformations & PNG_FILLER) | |
png_ptr->transformations |= PNG_ADD_ALPHA; | |
} | |
#endif | |
#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \ | |
defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) | |
void PNGAPI | |
png_set_swap_alpha(png_structrp png_ptr) | |
{ | |
png_debug(1, "in png_set_swap_alpha"); | |
if (png_ptr == NULL) | |
return; | |
png_ptr->transformations |= PNG_SWAP_ALPHA; | |
} | |
#endif | |
#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \ | |
defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) | |
void PNGAPI | |
png_set_invert_alpha(png_structrp png_ptr) | |
{ | |
png_debug(1, "in png_set_invert_alpha"); | |
if (png_ptr == NULL) | |
return; | |
png_ptr->transformations |= PNG_INVERT_ALPHA; | |
} | |
#endif | |
#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED) | |
void PNGAPI | |
png_set_invert_mono(png_structrp png_ptr) | |
{ | |
png_debug(1, "in png_set_invert_mono"); | |
if (png_ptr == NULL) | |
return; | |
png_ptr->transformations |= PNG_INVERT_MONO; | |
} | |
/* Invert monochrome grayscale data */ | |
void /* PRIVATE */ | |
png_do_invert(png_row_infop row_info, png_bytep row) | |
{ | |
png_debug(1, "in png_do_invert"); | |
/* This test removed from libpng version 1.0.13 and 1.2.0: | |
* if (row_info->bit_depth == 1 && | |
*/ | |
if (row_info->color_type == PNG_COLOR_TYPE_GRAY) | |
{ | |
png_bytep rp = row; | |
png_size_t i; | |
png_size_t istop = row_info->rowbytes; | |
for (i = 0; i < istop; i++) | |
{ | |
*rp = (png_byte)(~(*rp)); | |
rp++; | |
} | |
} | |
else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && | |
row_info->bit_depth == 8) | |
{ | |
png_bytep rp = row; | |
png_size_t i; | |
png_size_t istop = row_info->rowbytes; | |
for (i = 0; i < istop; i += 2) | |
{ | |
*rp = (png_byte)(~(*rp)); | |
rp += 2; | |
} | |
} | |
#ifdef PNG_16BIT_SUPPORTED | |
else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && | |
row_info->bit_depth == 16) | |
{ | |
png_bytep rp = row; | |
png_size_t i; | |
png_size_t istop = row_info->rowbytes; | |
for (i = 0; i < istop; i += 4) | |
{ | |
*rp = (png_byte)(~(*rp)); | |
*(rp + 1) = (png_byte)(~(*(rp + 1))); | |
rp += 4; | |
} | |
} | |
#endif | |
} | |
#endif | |
#ifdef PNG_16BIT_SUPPORTED | |
#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) | |
/* Swaps byte order on 16 bit depth images */ | |
void /* PRIVATE */ | |
png_do_swap(png_row_infop row_info, png_bytep row) | |
{ | |
png_debug(1, "in png_do_swap"); | |
if (row_info->bit_depth == 16) | |
{ | |
png_bytep rp = row; | |
png_uint_32 i; | |
png_uint_32 istop= row_info->width * row_info->channels; | |
for (i = 0; i < istop; i++, rp += 2) | |
{ | |
png_byte t = *rp; | |
*rp = *(rp + 1); | |
*(rp + 1) = t; | |
} | |
} | |
} | |
#endif | |
#endif | |
#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED) | |
static PNG_CONST png_byte onebppswaptable[256] = { | |
0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, | |
0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0, | |
0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, | |
0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8, | |
0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, | |
0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4, | |
0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, | |
0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC, | |
0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, | |
0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2, | |
0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, | |
0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA, | |
0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, | |
0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6, | |
0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, | |
0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE, | |
0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1, | |
0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1, | |
0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, | |
0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9, | |
0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, | |
0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5, | |
0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, | |
0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD, | |
0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, | |
0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3, | |
0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, | |
0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB, | |
0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7, | |
0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7, | |
0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, | |
0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF | |
}; | |
static PNG_CONST png_byte twobppswaptable[256] = { | |
0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0, | |
0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0, | |
0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4, | |
0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4, | |
0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8, | |
0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8, | |
0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC, | |
0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC, | |
0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1, | |
0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1, | |
0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5, | |
0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5, | |
0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9, | |
0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9, | |
0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD, | |
0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD, | |
0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2, | |
0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2, | |
0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6, | |
0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6, | |
0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA, | |
0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA, | |
0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE, | |
0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE, | |
0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3, | |
0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3, | |
0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7, | |
0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7, | |
0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB, | |
0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB, | |
0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF, | |
0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF | |
}; | |
static PNG_CONST png_byte fourbppswaptable[256] = { | |
0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70, | |
0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0, | |
0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71, | |
0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1, | |
0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72, | |
0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2, | |
0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73, | |
0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3, | |
0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74, | |
0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4, | |
0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75, | |
0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5, | |
0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76, | |
0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6, | |
0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77, | |
0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7, | |
0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78, | |
0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8, | |
0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79, | |
0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9, | |
0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A, | |
0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA, | |
0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B, | |
0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB, | |
0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C, | |
0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC, | |
0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D, | |
0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD, | |
0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E, | |
0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE, | |
0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F, | |
0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF | |
}; | |
/* Swaps pixel packing order within bytes */ | |
void /* PRIVATE */ | |
png_do_packswap(png_row_infop row_info, png_bytep row) | |
{ | |
png_debug(1, "in png_do_packswap"); | |
if (row_info->bit_depth < 8) | |
{ | |
png_bytep rp; | |
png_const_bytep end, table; | |
end = row + row_info->rowbytes; | |
if (row_info->bit_depth == 1) | |
table = onebppswaptable; | |
else if (row_info->bit_depth == 2) | |
table = twobppswaptable; | |
else if (row_info->bit_depth == 4) | |
table = fourbppswaptable; | |
else | |
return; | |
for (rp = row; rp < end; rp++) | |
*rp = table[*rp]; | |
} | |
} | |
#endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */ | |
#if defined(PNG_WRITE_FILLER_SUPPORTED) || \ | |
defined(PNG_READ_STRIP_ALPHA_SUPPORTED) | |
/* Remove a channel - this used to be 'png_do_strip_filler' but it used a | |
* somewhat weird combination of flags to determine what to do. All the calls | |
* to png_do_strip_filler are changed in 1.5.2 to call this instead with the | |
* correct arguments. | |
* | |
* The routine isn't general - the channel must be the channel at the start or | |
* end (not in the middle) of each pixel. | |
*/ | |
void /* PRIVATE */ | |
png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start) | |
{ | |
png_bytep sp = row; /* source pointer */ | |
png_bytep dp = row; /* destination pointer */ | |
png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */ | |
/* At the start sp will point to the first byte to copy and dp to where | |
* it is copied to. ep always points just beyond the end of the row, so | |
* the loop simply copies (channels-1) channels until sp reaches ep. | |
* | |
* at_start: 0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc. | |
* nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc. | |
*/ | |
/* GA, GX, XG cases */ | |
if (row_info->channels == 2) | |
{ | |
if (row_info->bit_depth == 8) | |
{ | |
if (at_start) /* Skip initial filler */ | |
++sp; | |
else /* Skip initial channel and, for sp, the filler */ | |
sp += 2, ++dp; | |
/* For a 1 pixel wide image there is nothing to do */ | |
while (sp < ep) | |
*dp++ = *sp, sp += 2; | |
row_info->pixel_depth = 8; | |
} | |
else if (row_info->bit_depth == 16) | |
{ | |
if (at_start) /* Skip initial filler */ | |
sp += 2; | |
else /* Skip initial channel and, for sp, the filler */ | |
sp += 4, dp += 2; | |
while (sp < ep) | |
*dp++ = *sp++, *dp++ = *sp, sp += 3; | |
row_info->pixel_depth = 16; | |
} | |
else | |
return; /* bad bit depth */ | |
row_info->channels = 1; | |
/* Finally fix the color type if it records an alpha channel */ | |
if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) | |
row_info->color_type = PNG_COLOR_TYPE_GRAY; | |
} | |
/* RGBA, RGBX, XRGB cases */ | |
else if (row_info->channels == 4) | |
{ | |
if (row_info->bit_depth == 8) | |
{ | |
if (at_start) /* Skip initial filler */ | |
++sp; | |
else /* Skip initial channels and, for sp, the filler */ | |
sp += 4, dp += 3; | |
/* Note that the loop adds 3 to dp and 4 to sp each time. */ | |
while (sp < ep) | |
*dp++ = *sp++, *dp++ = *sp++, *dp++ = *sp, sp += 2; | |
row_info->pixel_depth = 24; | |
} | |
else if (row_info->bit_depth == 16) | |
{ | |
if (at_start) /* Skip initial filler */ | |
sp += 2; | |
else /* Skip initial channels and, for sp, the filler */ | |
sp += 8, dp += 6; | |
while (sp < ep) | |
{ | |
/* Copy 6 bytes, skip 2 */ | |
*dp++ = *sp++, *dp++ = *sp++; | |
*dp++ = *sp++, *dp++ = *sp++; | |
*dp++ = *sp++, *dp++ = *sp, sp += 3; | |
} | |
row_info->pixel_depth = 48; | |
} | |
else | |
return; /* bad bit depth */ | |
row_info->channels = 3; | |
/* Finally fix the color type if it records an alpha channel */ | |
if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
row_info->color_type = PNG_COLOR_TYPE_RGB; | |
} | |
else | |
return; /* The filler channel has gone already */ | |
/* Fix the rowbytes value. */ | |
row_info->rowbytes = dp-row; | |
} | |
#endif | |
#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) | |
/* Swaps red and blue bytes within a pixel */ | |
void /* PRIVATE */ | |
png_do_bgr(png_row_infop row_info, png_bytep row) | |
{ | |
png_debug(1, "in png_do_bgr"); | |
if ((row_info->color_type & PNG_COLOR_MASK_COLOR)) | |
{ | |
png_uint_32 row_width = row_info->width; | |
if (row_info->bit_depth == 8) | |
{ | |
if (row_info->color_type == PNG_COLOR_TYPE_RGB) | |
{ | |
png_bytep rp; | |
png_uint_32 i; | |
for (i = 0, rp = row; i < row_width; i++, rp += 3) | |
{ | |
png_byte save = *rp; | |
*rp = *(rp + 2); | |
*(rp + 2) = save; | |
} | |
} | |
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
{ | |
png_bytep rp; | |
png_uint_32 i; | |
for (i = 0, rp = row; i < row_width; i++, rp += 4) | |
{ | |
png_byte save = *rp; | |
*rp = *(rp + 2); | |
*(rp + 2) = save; | |
} | |
} | |
} | |
#ifdef PNG_16BIT_SUPPORTED | |
else if (row_info->bit_depth == 16) | |
{ | |
if (row_info->color_type == PNG_COLOR_TYPE_RGB) | |
{ | |
png_bytep rp; | |
png_uint_32 i; | |
for (i = 0, rp = row; i < row_width; i++, rp += 6) | |
{ | |
png_byte save = *rp; | |
*rp = *(rp + 4); | |
*(rp + 4) = save; | |
save = *(rp + 1); | |
*(rp + 1) = *(rp + 5); | |
*(rp + 5) = save; | |
} | |
} | |
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
{ | |
png_bytep rp; | |
png_uint_32 i; | |
for (i = 0, rp = row; i < row_width; i++, rp += 8) | |
{ | |
png_byte save = *rp; | |
*rp = *(rp + 4); | |
*(rp + 4) = save; | |
save = *(rp + 1); | |
*(rp + 1) = *(rp + 5); | |
*(rp + 5) = save; | |
} | |
} | |
} | |
#endif | |
} | |
} | |
#endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */ | |
#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \ | |
defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED) | |
/* Added at libpng-1.5.10 */ | |
void /* PRIVATE */ | |
png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info) | |
{ | |
if (png_ptr->num_palette < (1 << row_info->bit_depth) && | |
png_ptr->num_palette > 0) /* num_palette can be 0 in MNG files */ | |
{ | |
/* Calculations moved outside switch in an attempt to stop different | |
* compiler warnings. 'padding' is in *bits* within the last byte, it is | |
* an 'int' because pixel_depth becomes an 'int' in the expression below, | |
* and this calculation is used because it avoids warnings that other | |
* forms produced on either GCC or MSVC. | |
*/ | |
int padding = (-row_info->pixel_depth * row_info->width) & 7; | |
png_bytep rp = png_ptr->row_buf + row_info->rowbytes; | |
switch (row_info->bit_depth) | |
{ | |
case 1: | |
{ | |
/* in this case, all bytes must be 0 so we don't need | |
* to unpack the pixels except for the rightmost one. | |
*/ | |
for (; rp > png_ptr->row_buf; rp--) | |
{ | |
if (*rp >> padding != 0) | |
png_ptr->num_palette_max = 1; | |
padding = 0; | |
} | |
break; | |
} | |
case 2: | |
{ | |
for (; rp > png_ptr->row_buf; rp--) | |
{ | |
int i = ((*rp >> padding) & 0x03); | |
if (i > png_ptr->num_palette_max) | |
png_ptr->num_palette_max = i; | |
i = (((*rp >> padding) >> 2) & 0x03); | |
if (i > png_ptr->num_palette_max) | |
png_ptr->num_palette_max = i; | |
i = (((*rp >> padding) >> 4) & 0x03); | |
if (i > png_ptr->num_palette_max) | |
png_ptr->num_palette_max = i; | |
i = (((*rp >> padding) >> 6) & 0x03); | |
if (i > png_ptr->num_palette_max) | |
png_ptr->num_palette_max = i; | |
padding = 0; | |
} | |
break; | |
} | |
case 4: | |
{ | |
for (; rp > png_ptr->row_buf; rp--) | |
{ | |
int i = ((*rp >> padding) & 0x0f); | |
if (i > png_ptr->num_palette_max) | |
png_ptr->num_palette_max = i; | |
i = (((*rp >> padding) >> 4) & 0x0f); | |
if (i > png_ptr->num_palette_max) | |
png_ptr->num_palette_max = i; | |
padding = 0; | |
} | |
break; | |
} | |
case 8: | |
{ | |
for (; rp > png_ptr->row_buf; rp--) | |
{ | |
if (*rp > png_ptr->num_palette_max) | |
png_ptr->num_palette_max = (int) *rp; | |
} | |
break; | |
} | |
default: | |
break; | |
} | |
} | |
} | |
#endif /* PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED */ | |
#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ | |
defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) | |
#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED | |
void PNGAPI | |
png_set_user_transform_info(png_structrp png_ptr, png_voidp | |
user_transform_ptr, int user_transform_depth, int user_transform_channels) | |
{ | |
png_debug(1, "in png_set_user_transform_info"); | |
if (png_ptr == NULL) | |
return; | |
#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED | |
if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && | |
(png_ptr->flags & PNG_FLAG_ROW_INIT) != 0) | |
{ | |
png_app_error(png_ptr, | |
"info change after png_start_read_image or png_read_update_info"); | |
return; | |
} | |
#endif | |
png_ptr->user_transform_ptr = user_transform_ptr; | |
png_ptr->user_transform_depth = (png_byte)user_transform_depth; | |
png_ptr->user_transform_channels = (png_byte)user_transform_channels; | |
} | |
#endif | |
/* This function returns a pointer to the user_transform_ptr associated with | |
* the user transform functions. The application should free any memory | |
* associated with this pointer before png_write_destroy and png_read_destroy | |
* are called. | |
*/ | |
#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED | |
png_voidp PNGAPI | |
png_get_user_transform_ptr(png_const_structrp png_ptr) | |
{ | |
if (png_ptr == NULL) | |
return (NULL); | |
return png_ptr->user_transform_ptr; | |
} | |
#endif | |
#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED | |
png_uint_32 PNGAPI | |
png_get_current_row_number(png_const_structrp png_ptr) | |
{ | |
/* See the comments in png.h - this is the sub-image row when reading and | |
* interlaced image. | |
*/ | |
if (png_ptr != NULL) | |
return png_ptr->row_number; | |
return PNG_UINT_32_MAX; /* help the app not to fail silently */ | |
} | |
png_byte PNGAPI | |
png_get_current_pass_number(png_const_structrp png_ptr) | |
{ | |
if (png_ptr != NULL) | |
return png_ptr->pass; | |
return 8; /* invalid */ | |
} | |
#endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */ | |
#endif /* PNG_READ_USER_TRANSFORM_SUPPORTED || | |
PNG_WRITE_USER_TRANSFORM_SUPPORTED */ | |
#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ |