f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* pngread.c - read a PNG file
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * libpng 1.2.8 - December 3, 2004
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * For conditions of distribution and use, see copyright notice in png.h
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * Copyright (c) 1998-2004 Glenn Randers-Pehrson
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * This file contains routines that an application calls directly to
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * read a PNG file or stream.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* Create a PNG structure for reading, and allocate any memory needed. */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* Alternate create PNG structure for reading, and allocate any memory needed. */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_USER_MEM_SUPPORTED */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_1_0_X */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* added at libpng-1.2.6 */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync } while (png_libpng_ver[i++]);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * we must recompile any applications that use any older library version.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * For versions after libpng 1.0, we will be compatible, so we need
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * only check the first digit.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync sprintf(msg, "Application is running with png.c from libpng-%.20s",
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync "Incompatible libpng version in application and library");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* initialize zbuf - compression buffer */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error"); break;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* Applications that neglect to set up their own setjmp() and then encounter
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync a png_error() will longjmp here. Since the jmpbuf is then meaningless we
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync abort instead of returning. */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* Initialize PNG structure for reading, and allocate any memory needed.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync This interface is deprecated in favour of the png_create_read_struct(),
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync and it will eventually disappear. */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* We only come here via pre-1.0.7-compiled applications */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_size_t png_struct_size, png_size_t png_info_size)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* We only come here via pre-1.0.12-compiled applications */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync sprintf(msg, "Application is running with png.c from libpng-%.20s",
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync "The png struct allocated by the application for reading is too small.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync "The info struct allocated by application for reading is too small.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_read_init_3(&png_ptr, user_png_ver, png_struct_size);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync "Application uses deprecated png_read_init() and should be recompiled.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync } while (png_libpng_ver[i++]);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* save jump buffer and error functions */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync *ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* reset all variables to 0 */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* restore jump buffer */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* added at libpng-1.2.6 */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* initialize zbuf - compression buffer */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory"); break;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync case Z_VERSION_ERROR: png_error(png_ptr, "zlib version"); break;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* Read the information before the actual image data. This has been
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * changed in v0.90 to allow reading a file that already has the magic
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * bytes read from the stream. You can tell libpng how many bytes have
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * been read from the beginning of the stream (up to the maximum of 8)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * via png_set_sig_bytes(), and we will only check the remaining bytes
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * here. The application can then have access to the signature bytes we
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * read if it is determined that this isn't a valid PNG file.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_read_info(png_structp png_ptr, png_infop info_ptr)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* If we haven't checked all of the PNG signature bytes, do so now. */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_error(png_ptr, "PNG file corrupted by ASCII conversion");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_USE_LOCAL_ARRAYS */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_debug2(0, "Reading %s chunk, length=%lu.\n", png_ptr->chunk_name,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* This should be a binary subdivision search or a hash for
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * matching the chunk name rather than a linear search.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* optional call to update the users info_ptr structure */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_read_update_info(png_structp png_ptr, png_infop info_ptr)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync "Ignoring extra png_read_update_info() call; row buffer not reallocated");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* Initialize palette, background, etc, after transformations
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * are set, but before any reading takes place. This allows
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * the user to obtain a gamma-corrected palette, for example.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * If the user doesn't call this, we will do it ourselves.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync const int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync const int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_debug2(1, "in png_read_row (row %lu, pass %d)\n",
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if (png_ptr->row_number == 0 && png_ptr->pass == 0)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* check for transforms that have been set but were defined out */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && !defined(PNG_READ_PACKSWAP_SUPPORTED)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* if interlaced and we do not need a new row, combine row and return */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if ((png_ptr->row_number & 3) || png_ptr->width < 3)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if ((png_ptr->row_number & 1) || png_ptr->width < 2)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_error(png_ptr, "Invalid attempt to read row data");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->idat_size = png_get_uint_31(png_ptr,chunk_length);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync "Decompression error");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->row_info.color_type = png_ptr->color_type;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* Intrapixel differencing */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* blow up interlaced rows to full size */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* old interface (pre-1.0.9):
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_do_read_interlace(&(png_ptr->row_info),
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* Read one or more rows of image data. If the image is interlaced,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * and png_set_interlace_handling() has been called, the rows need to
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * contain the contents of the rows from the previous pass. If the
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * image has alpha or transparency, and png_handle_alpha()[*] has been
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * called, the rows contents must be initialized to the contents of the
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * "row" holds the actual image, and pixels are placed in it
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * as they arrive. If the image is displayed after each pass, it will
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * appear to "sparkle" in. "display_row" can be used to display a
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * "chunky" progressive image, with finer detail added as it becomes
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * available. If you do not want this "chunky" display, you may pass
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * NULL for display_row. If you do not want the sparkle display, and
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * you have not called png_handle_alpha(), you may pass NULL for rows.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * If you have called png_handle_alpha(), and the image has either an
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * alpha channel or a transparency chunk, you must provide a buffer for
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * rows. In this case, you do not have to provide a display_row buffer
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * also, but you may. If the image is not interlaced, or if you have
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * not called png_set_interlace_handling(), the display_row buffer will
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * be ignored, so pass NULL to it.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * [*] png_handle_alpha() does not exist yet, as of libpng version 1.2.8
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync for (i = 0; i < num_rows; i++)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync for (i = 0; i < num_rows; i++)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync for (i = 0; i < num_rows; i++)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* Read the entire image. If the image has an alpha channel or a tRNS
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * chunk, and you have called png_handle_alpha()[*], you will need to
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * initialize the image to the current image that PNG will be overlaying.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * We set the num_rows again here, in case it was incorrectly set in
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * png_read_start_row() by a call to png_read_update_info() or
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * png_start_read_image() if png_set_interlace_handling() wasn't called
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * prior to either of these functions like it should have been. You can
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * only call this function once. If you desire to have an image for
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * each pass of a interlaced image, use png_read_rows() instead.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * [*] png_handle_alpha() does not exist yet, as of libpng version 1.2.8
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_read_image(png_structp png_ptr, png_bytepp image)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync "Cannot read interlaced image -- interlace handler disabled.");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_ptr->num_rows = image_height; /* Make sure this is set correctly */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync for (j = 0; j < pass; j++)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync for (i = 0; i < image_height; i++)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* Read the end of the PNG file. Will not read past the end of the
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * file, will verify the end is accurate, and will read any comments
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * or time information at the end of the file, if info is not NULL.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_read_end(png_structp png_ptr, png_infop info_ptr)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_USE_LOCAL_ARRAYS */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_debug1(0, "Reading %s chunk.\n", png_ptr->chunk_name);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* Zero length IDATs are legal after the last IDAT has been
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * read, but not after other chunks have been read.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* free all memory used by the read */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync/* free all memory used by the read (old method) */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncvoid /* PRIVATE */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_read_destroy(png_structp png_ptr, png_infop info_ptr, png_infop end_info_ptr)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#if defined(PNG_tRNS_SUPPORTED) || \
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync for (i = 0; i < istop; i++)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync for (i = 0; i < istop; i++)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync for (i = 0; i < istop; i++)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_TEXT_SUPPORTED */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* Save the important info out of the png_struct, in case it is
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * being used again.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsyncpng_read_png(png_structp png_ptr, png_infop info_ptr,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* invert the alpha channel from opacity to transparency
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* png_read_info() gives us all of the information from the
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * PNG file before the first IDAT (image data chunk).
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_error(png_ptr,"Image is too high to process with png_read_png()");
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* -------------- image transformations start here ------------------- */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* tell libpng to strip 16 bit/color files down to 8 bits per color
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* Strip alpha bytes from the input data without combining with
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * the background (not recommended).
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * byte into separate bytes (useful for paletted and grayscale images).
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* Change the order of packed pixels to least significant bit first
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * (not useful if you are using png_set_packing).
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* Expand paletted colors into true RGB triplets
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * Expand paletted or RGB images with transparency to full alpha
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * channels so the data will be available as RGBA quartets.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* We don't handle background color or gamma transformation or dithering.
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* invert monochrome files to have 0 as white and 1 as black
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* If you want to shift the pixel values from the range [0,255] or
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * [0,65535] to the original [0,7] or [0,31], or whatever range the
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * colors were originally in:
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* flip the RGB pixels to BGR (or RGBA to BGRA)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* swap bytes of 16 bit files to least significant byte first
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* We don't handle adding filler bytes */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* Optional call to gamma correct and add the background to the palette
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * and update info structure. REQUIRED if you are expecting libpng to
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync * update the palette for you (i.e., you selected such a transform above).
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* -------------- image transformations end here ------------------- */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync /* quiet compiler warnings */ return;
f9a51917495bc8ba8b60632219652a7b122c1190vboxsync#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */