www.pudn.com > transparentdib.zip > pngread.c
/* pngread.c - read a PNG file
*
* libpng 1.0.12 - June 8, 2001
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1998-2001 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 file contains routines that an application calls directly to
* read a PNG file or stream.
*/
#define PNG_INTERNAL
#include "png.h"
/* Create a PNG structure for reading, and allocate any memory needed. */
png_structp PNGAPI
png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn)
{
#ifdef PNG_USER_MEM_SUPPORTED
return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
warn_fn, NULL, NULL, NULL));
}
/* Alternate create PNG structure for reading, and allocate any memory needed. */
png_structp PNGAPI
png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
png_malloc_ptr malloc_fn, png_free_ptr free_fn)
{
#endif /* PNG_USER_MEM_SUPPORTED */
png_structp png_ptr;
#ifdef PNG_SETJMP_SUPPORTED
#ifdef USE_FAR_KEYWORD
jmp_buf jmpbuf;
#endif
#endif
int i;
png_debug(1, "in png_create_read_struct\n");
#ifdef PNG_USER_MEM_SUPPORTED
if ((png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
(png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr)) == NULL)
#else
if ((png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG)) == NULL)
#endif
{
return (png_structp)NULL;
}
#ifdef PNG_SETJMP_SUPPORTED
#ifdef USE_FAR_KEYWORD
if (setjmp(jmpbuf))
#else
if (setjmp(png_ptr->jmpbuf))
#endif
{
png_free(png_ptr, png_ptr->zbuf);
png_ptr->zbuf=NULL;
png_destroy_struct(png_ptr);
return (png_structp)NULL;
}
#ifdef USE_FAR_KEYWORD
png_memcpy(png_ptr->jmpbuf,jmpbuf,sizeof(jmp_buf));
#endif
#endif
#ifdef PNG_USER_MEM_SUPPORTED
png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
#endif
png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
i=0;
do
{
if(user_png_ver[i] != png_libpng_ver[i])
png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
} while (png_libpng_ver[i++]);
if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
{
/* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
* we must recompile any applications that use any older library version.
* For versions after libpng 1.0, we will be compatible, so we need
* only check the first digit.
*/
if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
(user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
(user_png_ver[0] == '0' && user_png_ver[2] < '9'))
{
#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
char msg[80];
if (user_png_ver)
{
sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
user_png_ver);
png_warning(png_ptr, msg);
}
sprintf(msg, "Application is running with png.c from libpng-%.20s",
png_libpng_ver);
png_warning(png_ptr, msg);
#endif
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
png_ptr->flags=0;
#endif
png_error(png_ptr,
"Incompatible libpng version in application and library");
}
/* Libpng 1.0.6 was not binary compatible, due to insertion of the
info_ptr->free_me member. Libpng-1.0.1 and earlier were not
compatible due to insertion of the user transform function. Note
to maintainer: this test can be removed from version 1.2.0 and
beyond because the previous test would have already rejected it. */
if (user_png_ver[0] == '1' && user_png_ver[2] == '0' &&
(user_png_ver[4] < '2' || user_png_ver[4] == '6') &&
user_png_ver[5] == '\0')
{
#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
char msg[80];
if (user_png_ver)
{
sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
user_png_ver);
png_warning(png_ptr, msg);
}
sprintf(msg, "Application is running with png.c from libpng-%.20s",
png_libpng_ver);
png_warning(png_ptr, msg);
#endif
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
png_ptr->flags=0;
#endif
png_error(png_ptr,
"Application must be recompiled; versions <= 1.0.6 were incompatible");
}
}
/* initialize zbuf - compression buffer */
png_ptr->zbuf_size = PNG_ZBUF_SIZE;
png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
(png_uint_32)png_ptr->zbuf_size);
png_ptr->zstream.zalloc = png_zalloc;
png_ptr->zstream.zfree = png_zfree;
png_ptr->zstream.opaque = (voidpf)png_ptr;
switch (inflateInit(&png_ptr->zstream))
{
case Z_OK: /* Do nothing */ break;
case Z_MEM_ERROR:
case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break;
case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error"); break;
default: png_error(png_ptr, "Unknown zlib error");
}
png_ptr->zstream.next_out = png_ptr->zbuf;
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
png_set_read_fn(png_ptr, NULL, NULL);
return (png_ptr);
}
/* Initialize PNG structure for reading, and allocate any memory needed.
This interface is deprecated in favour of the png_create_read_struct(),
and it will eventually disappear. */
#undef png_read_init
void PNGAPI
png_read_init(png_structp png_ptr)
{
/* We only come here via pre-1.0.7-compiled applications */
png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
}
#undef png_read_init_2
void PNGAPI
png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,
png_size_t png_struct_size, png_size_t png_info_size)
{
/* We only come here via pre-1.0.12-compiled applications */
#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
if(sizeof(png_struct) > png_struct_size || sizeof(png_info) > png_info_size)
{
char msg[80];
png_ptr->warning_fn=(png_error_ptr)NULL;
if (user_png_ver)
{
sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
user_png_ver);
png_warning(png_ptr, msg);
}
sprintf(msg, "Application is running with png.c from libpng-%.20s",
png_libpng_ver);
png_warning(png_ptr, msg);
}
#endif
if(sizeof(png_struct) > png_struct_size)
{
png_ptr->error_fn=(png_error_ptr)NULL;
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
png_ptr->flags=0;
#endif
png_error(png_ptr,
"The png struct allocated by the application for reading is too small.");
}
if(sizeof(png_info) > png_info_size)
{
png_ptr->error_fn=(png_error_ptr)NULL;
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
png_ptr->flags=0;
#endif
png_error(png_ptr,
"The info struct allocated by application for reading is too small.");
}
png_read_init_3(&png_ptr, user_png_ver, png_struct_size);
}
void PNGAPI
png_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
png_size_t png_struct_size)
{
#ifdef PNG_SETJMP_SUPPORTED
jmp_buf tmp_jmp; /* to save current jump buffer */
#endif
int i=0;
png_structp png_ptr=*ptr_ptr;
do
{
if(user_png_ver[i] != png_libpng_ver[i])
{
#ifdef PNG_LEGACY_SUPPORTED
png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
#else
png_ptr->warning_fn=(png_error_ptr)NULL;
png_warning(png_ptr,
"Application uses deprecated png_read_init() and should be recompiled.");
break;
#endif
}
} while (png_libpng_ver[i++]);
png_debug(1, "in png_read_init_3\n");
#ifdef PNG_SETJMP_SUPPORTED
/* save jump buffer and error functions */
png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
#endif
if(sizeof(png_struct) > png_struct_size)
{
png_destroy_struct(png_ptr);
*ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
png_ptr = *ptr_ptr;
}
/* reset all variables to 0 */
png_memset(png_ptr, 0, sizeof (png_struct));
#ifdef PNG_SETJMP_SUPPORTED
/* restore jump buffer */
png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
#endif
/* initialize zbuf - compression buffer */
png_ptr->zbuf_size = PNG_ZBUF_SIZE;
png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
(png_uint_32)png_ptr->zbuf_size);
png_ptr->zstream.zalloc = png_zalloc;
png_ptr->zstream.zfree = png_zfree;
png_ptr->zstream.opaque = (voidpf)png_ptr;
switch (inflateInit(&png_ptr->zstream))
{
case Z_OK: /* Do nothing */ break;
case Z_MEM_ERROR:
case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory"); break;
case Z_VERSION_ERROR: png_error(png_ptr, "zlib version"); break;
default: png_error(png_ptr, "Unknown zlib error");
}
png_ptr->zstream.next_out = png_ptr->zbuf;
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
png_set_read_fn(png_ptr, NULL, NULL);
}
/* Read the information before the actual image data. This has been
* changed in v0.90 to allow reading a file that already has the magic
* bytes read from the stream. You can tell libpng how many bytes have
* been read from the beginning of the stream (up to the maximum of 8)
* via png_set_sig_bytes(), and we will only check the remaining bytes
* here. The application can then have access to the signature bytes we
* read if it is determined that this isn't a valid PNG file.
*/
void PNGAPI
png_read_info(png_structp png_ptr, png_infop info_ptr)
{
png_debug(1, "in png_read_info\n");
/* save jump buffer and error functions */
/* If we haven't checked all of the PNG signature bytes, do so now. */
if (png_ptr->sig_bytes < 8)
{
png_size_t num_checked = png_ptr->sig_bytes,
num_to_check = 8 - num_checked;
png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
png_ptr->sig_bytes = 8;
if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
{
if (num_checked < 4 &&
png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
png_error(png_ptr, "Not a PNG file");
else
png_error(png_ptr, "PNG file corrupted by ASCII conversion");
}
if (num_checked < 3)
png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
}
for(;;)
{
#ifdef PNG_USE_LOCAL_ARRAYS
PNG_IHDR;
PNG_IDAT;
PNG_IEND;
PNG_PLTE;
#if defined(PNG_READ_bKGD_SUPPORTED)
PNG_bKGD;
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
PNG_cHRM;
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
PNG_gAMA;
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
PNG_hIST;
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
PNG_iCCP;
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
PNG_iTXt;
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
PNG_oFFs;
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
PNG_pCAL;
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
PNG_pHYs;
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
PNG_sBIT;
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
PNG_sCAL;
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
PNG_sPLT;
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
PNG_sRGB;
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
PNG_tEXt;
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
PNG_tIME;
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
PNG_tRNS;
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
PNG_zTXt;
#endif
#endif /* PNG_GLOBAL_ARRAYS */
png_byte chunk_length[4];
png_uint_32 length;
png_read_data(png_ptr, chunk_length, 4);
length = png_get_uint_32(chunk_length);
png_reset_crc(png_ptr);
png_crc_read(png_ptr, png_ptr->chunk_name, 4);
png_debug2(0, "Reading %s chunk, length=%lu.\n", png_ptr->chunk_name,
length);
/* This should be a binary subdivision search or a hash for
* matching the chunk name rather than a linear search.
*/
if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
png_handle_IHDR(png_ptr, info_ptr, length);
else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
png_handle_IEND(png_ptr, info_ptr, length);
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
{
if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
png_ptr->mode |= PNG_HAVE_IDAT;
png_handle_unknown(png_ptr, info_ptr, length);
if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
png_ptr->mode |= PNG_HAVE_PLTE;
else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
{
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before IDAT");
else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
!(png_ptr->mode & PNG_HAVE_PLTE))
png_error(png_ptr, "Missing PLTE before IDAT");
break;
}
}
#endif
else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
png_handle_PLTE(png_ptr, info_ptr, length);
else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
{
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before IDAT");
else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
!(png_ptr->mode & PNG_HAVE_PLTE))
png_error(png_ptr, "Missing PLTE before IDAT");
png_ptr->idat_size = length;
png_ptr->mode |= PNG_HAVE_IDAT;
break;
}
#if defined(PNG_READ_bKGD_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
png_handle_bKGD(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
png_handle_cHRM(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
png_handle_gAMA(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
png_handle_hIST(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
png_handle_oFFs(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
png_handle_pCAL(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
png_handle_sCAL(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
png_handle_pHYs(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
png_handle_sBIT(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
png_handle_sRGB(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
png_handle_iCCP(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
png_handle_sPLT(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
png_handle_tEXt(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
png_handle_tIME(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
png_handle_tRNS(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
png_handle_zTXt(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
png_handle_iTXt(png_ptr, info_ptr, length);
#endif
else
png_handle_unknown(png_ptr, info_ptr, length);
}
}
/* optional call to update the users info_ptr structure */
void PNGAPI
png_read_update_info(png_structp png_ptr, png_infop info_ptr)
{
png_debug(1, "in png_read_update_info\n");
/* save jump buffer and error functions */
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
png_read_start_row(png_ptr);
else
png_warning(png_ptr,
"Ignoring extra png_read_update_info() call; row buffer not reallocated");
png_read_transform_info(png_ptr, info_ptr);
}
/* Initialize palette, background, etc, after transformations
* are set, but before any reading takes place. This allows
* the user to obtain a gamma-corrected palette, for example.
* If the user doesn't call this, we will do it ourselves.
*/
void PNGAPI
png_start_read_image(png_structp png_ptr)
{
png_debug(1, "in png_start_read_image\n");
/* save jump buffer and error functions */
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
png_read_start_row(png_ptr);
}
void PNGAPI
png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
{
#ifdef PNG_USE_LOCAL_ARRAYS
PNG_IDAT;
const int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
const int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
#endif
int ret;
png_debug2(1, "in png_read_row (row %lu, pass %d)\n",
png_ptr->row_number, png_ptr->pass);
/* save jump buffer and error functions */
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
png_read_start_row(png_ptr);
if (png_ptr->row_number == 0 && png_ptr->pass == 0)
{
/* check for transforms that have been set but were defined out */
#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
if (png_ptr->transformations & PNG_INVERT_MONO)
png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
#endif
#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
if (png_ptr->transformations & PNG_FILLER)
png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");
#endif
#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && !defined(PNG_READ_PACKSWAP_SUPPORTED)
if (png_ptr->transformations & PNG_PACKSWAP)
png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined.");
#endif
#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
if (png_ptr->transformations & PNG_PACK)
png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined.");
#endif
#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
if (png_ptr->transformations & PNG_SHIFT)
png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined.");
#endif
#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
if (png_ptr->transformations & PNG_BGR)
png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");
#endif
#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
if (png_ptr->transformations & PNG_SWAP_BYTES)
png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");
#endif
}
#if defined(PNG_READ_INTERLACING_SUPPORTED)
/* if interlaced and we do not need a new row, combine row and return */
if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
{
switch (png_ptr->pass)
{
case 0:
if (png_ptr->row_number & 0x07)
{
if (dsp_row != NULL)
png_combine_row(png_ptr, dsp_row,
png_pass_dsp_mask[png_ptr->pass]);
png_read_finish_row(png_ptr);
return;
}
break;
case 1:
if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
{
if (dsp_row != NULL)
png_combine_row(png_ptr, dsp_row,
png_pass_dsp_mask[png_ptr->pass]);
png_read_finish_row(png_ptr);
return;
}
break;
case 2:
if ((png_ptr->row_number & 0x07) != 4)
{
if (dsp_row != NULL && (png_ptr->row_number & 4))
png_combine_row(png_ptr, dsp_row,
png_pass_dsp_mask[png_ptr->pass]);
png_read_finish_row(png_ptr);
return;
}
break;
case 3:
if ((png_ptr->row_number & 3) || png_ptr->width < 3)
{
if (dsp_row != NULL)
png_combine_row(png_ptr, dsp_row,
png_pass_dsp_mask[png_ptr->pass]);
png_read_finish_row(png_ptr);
return;
}
break;
case 4:
if ((png_ptr->row_number & 3) != 2)
{
if (dsp_row != NULL && (png_ptr->row_number & 2))
png_combine_row(png_ptr, dsp_row,
png_pass_dsp_mask[png_ptr->pass]);
png_read_finish_row(png_ptr);
return;
}
break;
case 5:
if ((png_ptr->row_number & 1) || png_ptr->width < 2)
{
if (dsp_row != NULL)
png_combine_row(png_ptr, dsp_row,
png_pass_dsp_mask[png_ptr->pass]);
png_read_finish_row(png_ptr);
return;
}
break;
case 6:
if (!(png_ptr->row_number & 1))
{
png_read_finish_row(png_ptr);
return;
}
break;
}
}
#endif
if (!(png_ptr->mode & PNG_HAVE_IDAT))
png_error(png_ptr, "Invalid attempt to read row data");
png_ptr->zstream.next_out = png_ptr->row_buf;
png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
do
{
if (!(png_ptr->zstream.avail_in))
{
while (!png_ptr->idat_size)
{
png_byte chunk_length[4];
png_crc_finish(png_ptr, 0);
png_read_data(png_ptr, chunk_length, 4);
png_ptr->idat_size = png_get_uint_32(chunk_length);
png_reset_crc(png_ptr);
png_crc_read(png_ptr, png_ptr->chunk_name, 4);
if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
png_error(png_ptr, "Not enough image data");
}
png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
png_ptr->zstream.next_in = png_ptr->zbuf;
if (png_ptr->zbuf_size > png_ptr->idat_size)
png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
png_crc_read(png_ptr, png_ptr->zbuf,
(png_size_t)png_ptr->zstream.avail_in);
png_ptr->idat_size -= png_ptr->zstream.avail_in;
}
ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
if (ret == Z_STREAM_END)
{
if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
png_ptr->idat_size)
png_error(png_ptr, "Extra compressed data");
png_ptr->mode |= PNG_AFTER_IDAT;
png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
break;
}
if (ret != Z_OK)
png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
"Decompression error");
} while (png_ptr->zstream.avail_out);
png_ptr->row_info.color_type = png_ptr->color_type;
png_ptr->row_info.width = png_ptr->iwidth;
png_ptr->row_info.channels = png_ptr->channels;
png_ptr->row_info.bit_depth = png_ptr->bit_depth;
png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *
(png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
if(png_ptr->row_buf[0])
png_read_filter_row(png_ptr, &(png_ptr->row_info),
png_ptr->row_buf + 1, png_ptr->prev_row + 1,
(int)(png_ptr->row_buf[0]));
png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
png_ptr->rowbytes + 1);
#if defined(PNG_MNG_FEATURES_SUPPORTED)
if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
(png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
{
/* Intrapixel differencing */
png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
}
#endif
if (png_ptr->transformations)
png_do_read_transformations(png_ptr);
#if defined(PNG_READ_INTERLACING_SUPPORTED)
/* blow up interlaced rows to full size */
if (png_ptr->interlaced &&
(png_ptr->transformations & PNG_INTERLACE))
{
if (png_ptr->pass < 6)
/* old interface (pre-1.0.9):
png_do_read_interlace(&(png_ptr->row_info),
png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
*/
png_do_read_interlace(png_ptr);
if (dsp_row != NULL)
png_combine_row(png_ptr, dsp_row,
png_pass_dsp_mask[png_ptr->pass]);
if (row != NULL)
png_combine_row(png_ptr, row,
png_pass_mask[png_ptr->pass]);
}
else
#endif
{
if (row != NULL)
png_combine_row(png_ptr, row, 0xff);
if (dsp_row != NULL)
png_combine_row(png_ptr, dsp_row, 0xff);
}
png_read_finish_row(png_ptr);
if (png_ptr->read_row_fn != NULL)
(*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
}
/* Read one or more rows of image data. If the image is interlaced,
* and png_set_interlace_handling() has been called, the rows need to
* contain the contents of the rows from the previous pass. If the
* image has alpha or transparency, and png_handle_alpha()[*] has been
* called, the rows contents must be initialized to the contents of the
* screen.
*
* "row" holds the actual image, and pixels are placed in it
* as they arrive. If the image is displayed after each pass, it will
* appear to "sparkle" in. "display_row" can be used to display a
* "chunky" progressive image, with finer detail added as it becomes
* available. If you do not want this "chunky" display, you may pass
* NULL for display_row. If you do not want the sparkle display, and
* you have not called png_handle_alpha(), you may pass NULL for rows.
* If you have called png_handle_alpha(), and the image has either an
* alpha channel or a transparency chunk, you must provide a buffer for
* rows. In this case, you do not have to provide a display_row buffer
* also, but you may. If the image is not interlaced, or if you have
* not called png_set_interlace_handling(), the display_row buffer will
* be ignored, so pass NULL to it.
*
* [*] png_handle_alpha() does not exist yet, as of libpng version 1.0.12
*/
void PNGAPI
png_read_rows(png_structp png_ptr, png_bytepp row,
png_bytepp display_row, png_uint_32 num_rows)
{
png_uint_32 i;
png_bytepp rp;
png_bytepp dp;
png_debug(1, "in png_read_rows\n");
/* save jump buffer and error functions */
rp = row;
dp = display_row;
if (rp != NULL && dp != NULL)
for (i = 0; i < num_rows; i++)
{
png_bytep rptr = *rp++;
png_bytep dptr = *dp++;
png_read_row(png_ptr, rptr, dptr);
}
else if(rp != NULL)
for (i = 0; i < num_rows; i++)
{
png_bytep rptr = *rp;
png_read_row(png_ptr, rptr, NULL);
rp++;
}
else if(dp != NULL)
for (i = 0; i < num_rows; i++)
{
png_bytep dptr = *dp;
png_read_row(png_ptr, NULL, dptr);
dp++;
}
}
/* Read the entire image. If the image has an alpha channel or a tRNS
* chunk, and you have called png_handle_alpha()[*], you will need to
* initialize the image to the current image that PNG will be overlaying.
* We set the num_rows again here, in case it was incorrectly set in
* png_read_start_row() by a call to png_read_update_info() or
* png_start_read_image() if png_set_interlace_handling() wasn't called
* prior to either of these functions like it should have been. You can
* only call this function once. If you desire to have an image for
* each pass of a interlaced image, use png_read_rows() instead.
*
* [*] png_handle_alpha() does not exist yet, as of libpng version 1.0.12
*/
void PNGAPI
png_read_image(png_structp png_ptr, png_bytepp image)
{
png_uint_32 i,image_height;
int pass, j;
png_bytepp rp;
png_debug(1, "in png_read_image\n");
/* save jump buffer and error functions */
#ifdef PNG_READ_INTERLACING_SUPPORTED
pass = png_set_interlace_handling(png_ptr);
#else
if (png_ptr->interlaced)
png_error(png_ptr,
"Cannot read interlaced image -- interlace handler disabled.");
pass = 1;
#endif
image_height=png_ptr->height;
png_ptr->num_rows = image_height; /* Make sure this is set correctly */
for (j = 0; j < pass; j++)
{
rp = image;
for (i = 0; i < image_height; i++)
{
png_read_row(png_ptr, *rp, NULL);
rp++;
}
}
}
/* Read the end of the PNG file. Will not read past the end of the
* file, will verify the end is accurate, and will read any comments
* or time information at the end of the file, if info is not NULL.
*/
void PNGAPI
png_read_end(png_structp png_ptr, png_infop info_ptr)
{
png_byte chunk_length[4];
png_uint_32 length;
png_debug(1, "in png_read_end\n");
/* save jump buffer and error functions */
png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
do
{
#ifdef PNG_USE_LOCAL_ARRAYS
PNG_IHDR;
PNG_IDAT;
PNG_IEND;
PNG_PLTE;
#if defined(PNG_READ_bKGD_SUPPORTED)
PNG_bKGD;
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
PNG_cHRM;
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
PNG_gAMA;
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
PNG_hIST;
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
PNG_iCCP;
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
PNG_iTXt;
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
PNG_oFFs;
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
PNG_pCAL;
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
PNG_pHYs;
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
PNG_sBIT;
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
PNG_sCAL;
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
PNG_sPLT;
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
PNG_sRGB;
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
PNG_tEXt;
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
PNG_tIME;
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
PNG_tRNS;
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
PNG_zTXt;
#endif
#endif /* PNG_GLOBAL_ARRAYS */
png_read_data(png_ptr, chunk_length, 4);
length = png_get_uint_32(chunk_length);
png_reset_crc(png_ptr);
png_crc_read(png_ptr, png_ptr->chunk_name, 4);
png_debug1(0, "Reading %s chunk.\n", png_ptr->chunk_name);
if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
png_handle_IHDR(png_ptr, info_ptr, length);
else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
png_handle_IEND(png_ptr, info_ptr, length);
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
{
if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
{
if (length > 0 || png_ptr->mode & PNG_AFTER_IDAT)
png_error(png_ptr, "Too many IDAT's found");
}
else
png_ptr->mode |= PNG_AFTER_IDAT;
png_handle_unknown(png_ptr, info_ptr, length);
if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
png_ptr->mode |= PNG_HAVE_PLTE;
}
#endif
else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
{
/* Zero length IDATs are legal after the last IDAT has been
* read, but not after other chunks have been read.
*/
if (length > 0 || png_ptr->mode & PNG_AFTER_IDAT)
png_error(png_ptr, "Too many IDAT's found");
png_crc_finish(png_ptr, length);
}
else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
png_handle_PLTE(png_ptr, info_ptr, length);
#if defined(PNG_READ_bKGD_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
png_handle_bKGD(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
png_handle_cHRM(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
png_handle_gAMA(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
png_handle_hIST(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
png_handle_oFFs(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
png_handle_pCAL(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
png_handle_sCAL(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
png_handle_pHYs(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
png_handle_sBIT(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
png_handle_sRGB(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
png_handle_iCCP(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
png_handle_sPLT(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
png_handle_tEXt(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
png_handle_tIME(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
png_handle_tRNS(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
png_handle_zTXt(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
png_handle_iTXt(png_ptr, info_ptr, length);
#endif
else
png_handle_unknown(png_ptr, info_ptr, length);
} while (!(png_ptr->mode & PNG_HAVE_IEND));
}
/* free all memory used by the read */
void PNGAPI
png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
png_infopp end_info_ptr_ptr)
{
png_structp png_ptr = NULL;
png_infop info_ptr = NULL, end_info_ptr = NULL;
#ifdef PNG_USER_MEM_SUPPORTED
png_free_ptr free_fn = NULL;
png_voidp mem_ptr = NULL;
#endif
png_debug(1, "in png_destroy_read_struct\n");
/* save jump buffer and error functions */
if (png_ptr_ptr != NULL)
png_ptr = *png_ptr_ptr;
if (info_ptr_ptr != NULL)
info_ptr = *info_ptr_ptr;
if (end_info_ptr_ptr != NULL)
end_info_ptr = *end_info_ptr_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
free_fn = png_ptr->free_fn;
mem_ptr = png_ptr->mem_ptr;
#endif
png_read_destroy(png_ptr, info_ptr, end_info_ptr);
if (info_ptr != NULL)
{
#if defined(PNG_TEXT_SUPPORTED)
png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
#endif
#ifdef PNG_USER_MEM_SUPPORTED
png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
(png_voidp)mem_ptr);
#else
png_destroy_struct((png_voidp)info_ptr);
#endif
*info_ptr_ptr = (png_infop)NULL;
}
if (end_info_ptr != NULL)
{
#if defined(PNG_READ_TEXT_SUPPORTED)
png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
#endif
#ifdef PNG_USER_MEM_SUPPORTED
png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
(png_voidp)mem_ptr);
#else
png_destroy_struct((png_voidp)end_info_ptr);
#endif
*end_info_ptr_ptr = (png_infop)NULL;
}
if (png_ptr != NULL)
{
#ifdef PNG_USER_MEM_SUPPORTED
png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
(png_voidp)mem_ptr);
#else
png_destroy_struct((png_voidp)png_ptr);
#endif
*png_ptr_ptr = (png_structp)NULL;
}
}
/* free all memory used by the read (old method) */
void /* PRIVATE */
png_read_destroy(png_structp png_ptr, png_infop info_ptr, png_infop end_info_ptr)
{
#ifdef PNG_SETJMP_SUPPORTED
jmp_buf tmp_jmp;
#endif
png_error_ptr error_fn;
png_error_ptr warning_fn;
png_voidp error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
png_free_ptr free_fn;
#endif
png_debug(1, "in png_read_destroy\n");
/* save jump buffer and error functions */
if (info_ptr != NULL)
png_info_destroy(png_ptr, info_ptr);
if (end_info_ptr != NULL)
png_info_destroy(png_ptr, end_info_ptr);
png_free(png_ptr, png_ptr->zbuf);
png_free(png_ptr, png_ptr->row_buf);
png_free(png_ptr, png_ptr->prev_row);
#if defined(PNG_READ_DITHER_SUPPORTED)
png_free(png_ptr, png_ptr->palette_lookup);
png_free(png_ptr, png_ptr->dither_index);
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED)
png_free(png_ptr, png_ptr->gamma_table);
#endif
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
png_free(png_ptr, png_ptr->gamma_from_1);
png_free(png_ptr, png_ptr->gamma_to_1);
#endif
#ifdef PNG_FREE_ME_SUPPORTED
if (png_ptr->free_me & PNG_FREE_PLTE)
png_zfree(png_ptr, png_ptr->palette);
png_ptr->free_me &= ~PNG_FREE_PLTE;
#else
if (png_ptr->flags & PNG_FLAG_FREE_PLTE)
png_zfree(png_ptr, png_ptr->palette);
png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
#endif
#if defined(PNG_tRNS_SUPPORTED) || \
defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
#ifdef PNG_FREE_ME_SUPPORTED
if (png_ptr->free_me & PNG_FREE_TRNS)
png_free(png_ptr, png_ptr->trans);
png_ptr->free_me &= ~PNG_FREE_TRNS;
#else
if (png_ptr->flags & PNG_FLAG_FREE_TRNS)
png_free(png_ptr, png_ptr->trans);
png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
#endif
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
#ifdef PNG_FREE_ME_SUPPORTED
if (png_ptr->free_me & PNG_FREE_HIST)
png_free(png_ptr, png_ptr->hist);
png_ptr->free_me &= ~PNG_FREE_HIST;
#else
if (png_ptr->flags & PNG_FLAG_FREE_HIST)
png_free(png_ptr, png_ptr->hist);
png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
#endif
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED)
if (png_ptr->gamma_16_table != NULL)
{
int i;
int istop = (1 << (8 - png_ptr->gamma_shift));
for (i = 0; i < istop; i++)
{
png_free(png_ptr, png_ptr->gamma_16_table[i]);
}
png_free(png_ptr, png_ptr->gamma_16_table);
}
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
if (png_ptr->gamma_16_from_1 != NULL)
{
int i;
int istop = (1 << (8 - png_ptr->gamma_shift));
for (i = 0; i < istop; i++)
{
png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
}
png_free(png_ptr, png_ptr->gamma_16_from_1);
}
if (png_ptr->gamma_16_to_1 != NULL)
{
int i;
int istop = (1 << (8 - png_ptr->gamma_shift));
for (i = 0; i < istop; i++)
{
png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
}
png_free(png_ptr, png_ptr->gamma_16_to_1);
}
#endif
#endif
#if defined(PNG_TIME_RFC1123_SUPPORTED)
png_free(png_ptr, png_ptr->time_buffer);
#endif
inflateEnd(&png_ptr->zstream);
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
png_free(png_ptr, png_ptr->save_buffer);
#endif
/* Save the important info out of the png_struct, in case it is
* being used again.
*/
#ifdef PNG_SETJMP_SUPPORTED
png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
#endif
error_fn = png_ptr->error_fn;
warning_fn = png_ptr->warning_fn;
error_ptr = png_ptr->error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
free_fn = png_ptr->free_fn;
#endif
png_memset(png_ptr, 0, sizeof (png_struct));
png_ptr->error_fn = error_fn;
png_ptr->warning_fn = warning_fn;
png_ptr->error_ptr = error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
png_ptr->free_fn = free_fn;
#endif
#ifdef PNG_SETJMP_SUPPORTED
png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
#endif
}
void PNGAPI
png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
{
png_ptr->read_row_fn = read_row_fn;
}
#if defined(PNG_INFO_IMAGE_SUPPORTED)
void PNGAPI
png_read_png(png_structp png_ptr, png_infop info_ptr,
int transforms,
voidp params)
{
int row;
#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
/* invert the alpha channel from opacity to transparency */
if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
png_set_invert_alpha(png_ptr);
#endif
/* The call to png_read_info() gives us all of the information from the
* PNG file before the first IDAT (image data chunk).
*/
png_read_info(png_ptr, info_ptr);
/* -------------- image transformations start here ------------------- */
#if defined(PNG_READ_16_TO_8_SUPPORTED)
/* tell libpng to strip 16 bit/color files down to 8 bits/color */
if (transforms & PNG_TRANSFORM_STRIP_16)
png_set_strip_16(png_ptr);
#endif
#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
/* Strip alpha bytes from the input data without combining with the
* background (not recommended).
*/
if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
png_set_strip_alpha(png_ptr);
#endif
#if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
/* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
* byte into separate bytes (useful for paletted and grayscale images).
*/
if (transforms & PNG_TRANSFORM_PACKING)
png_set_packing(png_ptr);
#endif
#if defined(PNG_READ_PACKSWAP_SUPPORTED)
/* Change the order of packed pixels to least significant bit first
* (not useful if you are using png_set_packing). */
if (transforms & PNG_TRANSFORM_PACKSWAP)
png_set_packswap(png_ptr);
#endif
#if defined(PNG_READ_EXPAND_SUPPORTED)
/* Expand paletted colors into true RGB triplets
* Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
* Expand paletted or RGB images with transparency to full alpha
* channels so the data will be available as RGBA quartets.
*/
if (transforms & PNG_TRANSFORM_EXPAND)
if ((png_ptr->bit_depth < 8) ||
(png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
(png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
png_set_expand(png_ptr);
#endif
/* We don't handle background color or gamma transformation or dithering. */
#if defined(PNG_READ_INVERT_SUPPORTED)
/* invert monochrome files to have 0 as white and 1 as black */
if (transforms & PNG_TRANSFORM_INVERT_MONO)
png_set_invert_mono(png_ptr);
#endif
#if defined(PNG_READ_SHIFT_SUPPORTED)
/* If you want to shift the pixel values from the range [0,255] or
* [0,65535] to the original [0,7] or [0,31], or whatever range the
* colors were originally in:
*/
if ((transforms & PNG_TRANSFORM_SHIFT)
&& png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
{
png_color_8p sig_bit;
png_get_sBIT(png_ptr, info_ptr, &sig_bit);
png_set_shift(png_ptr, sig_bit);
}
#endif
#if defined(PNG_READ_BGR_SUPPORTED)
/* flip the RGB pixels to BGR (or RGBA to BGRA) */
if (transforms & PNG_TRANSFORM_BGR)
png_set_bgr(png_ptr);
#endif
#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
/* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
png_set_swap_alpha(png_ptr);
#endif
#if defined(PNG_READ_SWAP_SUPPORTED)
/* swap bytes of 16 bit files to least significant byte first */
if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
png_set_swap(png_ptr);
#endif
/* We don't handle adding filler bytes */
/* Optional call to gamma correct and add the background to the palette
* and update info structure. REQUIRED if you are expecting libpng to
* update the palette for you (i.e., you selected such a transform above).
*/
png_read_update_info(png_ptr, info_ptr);
/* -------------- image transformations end here ------------------- */
#ifdef PNG_FREE_ME_SUPPORTED
png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
#endif
if(info_ptr->row_pointers == NULL)
{
info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
info_ptr->height * sizeof(png_bytep));
#ifdef PNG_FREE_ME_SUPPORTED
info_ptr->free_me |= PNG_FREE_ROWS;
#endif
for (row = 0; row < (int)info_ptr->height; row++)
{
info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
png_get_rowbytes(png_ptr, info_ptr));
}
}
png_read_image(png_ptr, info_ptr->row_pointers);
info_ptr->valid |= PNG_INFO_IDAT;
/* read rest of file, and get additional chunks in info_ptr - REQUIRED */
png_read_end(png_ptr, info_ptr);
if(transforms == 0 || params == NULL)
/* quiet compiler warnings */ return;
}
#endif