| Index: third_party/libpng/pngread.c
|
| diff --git a/third_party/lpng_v163/pngread.c b/third_party/libpng/pngread.c
|
| similarity index 88%
|
| rename from third_party/lpng_v163/pngread.c
|
| rename to third_party/libpng/pngread.c
|
| index b30c5a1009265fe6e56fe974fb472263cedef8e0..9cb4d2e41d222f47ae2856b51100a09b16d9df08 100644
|
| --- a/third_party/lpng_v163/pngread.c
|
| +++ b/third_party/libpng/pngread.c
|
| @@ -1,3999 +1,4136 @@
|
| -/* pngread.c - read a PNG file
|
| - *
|
| - * Last changed in libpng 1.6.1 [March 28, 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
|
| - *
|
| - * This file contains routines that an application calls directly to
|
| - * read a PNG file or stream.
|
| - */
|
| -
|
| -#include "pngpriv.h"
|
| -#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
|
| -# include <errno.h>
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_SUPPORTED
|
| -
|
| -/* Create a PNG structure for reading, and allocate any memory needed. */
|
| -PNG_FUNCTION(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),PNG_ALLOCATED)
|
| -{
|
| -#ifndef PNG_USER_MEM_SUPPORTED
|
| - png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
|
| - error_fn, warn_fn, NULL, NULL, NULL);
|
| -#else
|
| - 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_FUNCTION(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),PNG_ALLOCATED)
|
| -{
|
| - png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
|
| - error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
|
| -#endif /* PNG_USER_MEM_SUPPORTED */
|
| -
|
| - if (png_ptr != NULL)
|
| - {
|
| - png_ptr->mode = PNG_IS_READ_STRUCT;
|
| -
|
| - /* Added in libpng-1.6.0; this can be used to detect a read structure if
|
| - * required (it will be zero in a write structure.)
|
| - */
|
| -# ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| - png_ptr->IDAT_read_size = PNG_IDAT_READ_SIZE;
|
| -# endif
|
| -
|
| -# ifdef PNG_BENIGN_READ_ERRORS_SUPPORTED
|
| - png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
|
| -
|
| - /* In stable builds only warn if an application error can be completely
|
| - * handled.
|
| - */
|
| -# if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
|
| - png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
|
| -# endif
|
| -# endif
|
| -
|
| - /* TODO: delay this, it can be done in png_init_io (if the app doesn't
|
| - * do it itself) avoiding setting the default function if it is not
|
| - * required.
|
| - */
|
| - png_set_read_fn(png_ptr, NULL, NULL);
|
| - }
|
| -
|
| - return png_ptr;
|
| -}
|
| -
|
| -
|
| -#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| -/* 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_structrp png_ptr, png_inforp info_ptr)
|
| -{
|
| -#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| - int keep;
|
| -#endif
|
| -
|
| - png_debug(1, "in png_read_info");
|
| -
|
| - if (png_ptr == NULL || info_ptr == NULL)
|
| - return;
|
| -
|
| - /* Read and check the PNG file signature. */
|
| - png_read_sig(png_ptr, info_ptr);
|
| -
|
| - for (;;)
|
| - {
|
| - png_uint_32 length = png_read_chunk_header(png_ptr);
|
| - png_uint_32 chunk_name = png_ptr->chunk_name;
|
| -
|
| - /* IDAT logic needs to happen here to simplify getting the two flags
|
| - * right.
|
| - */
|
| - if (chunk_name == png_IDAT)
|
| - {
|
| - if (!(png_ptr->mode & PNG_HAVE_IHDR))
|
| - png_chunk_error(png_ptr, "Missing IHDR before IDAT");
|
| -
|
| - else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
|
| - !(png_ptr->mode & PNG_HAVE_PLTE))
|
| - png_chunk_error(png_ptr, "Missing PLTE before IDAT");
|
| -
|
| - else if (png_ptr->mode & PNG_AFTER_IDAT)
|
| - png_chunk_benign_error(png_ptr, "Too many IDATs found");
|
| -
|
| - png_ptr->mode |= PNG_HAVE_IDAT;
|
| - }
|
| -
|
| - else if (png_ptr->mode & PNG_HAVE_IDAT)
|
| - png_ptr->mode |= PNG_AFTER_IDAT;
|
| -
|
| - /* This should be a binary subdivision search or a hash for
|
| - * matching the chunk name rather than a linear search.
|
| - */
|
| - if (chunk_name == png_IHDR)
|
| - png_handle_IHDR(png_ptr, info_ptr, length);
|
| -
|
| - else if (chunk_name == png_IEND)
|
| - png_handle_IEND(png_ptr, info_ptr, length);
|
| -
|
| -#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| - else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
|
| - {
|
| - png_handle_unknown(png_ptr, info_ptr, length, keep);
|
| -
|
| - if (chunk_name == png_PLTE)
|
| - png_ptr->mode |= PNG_HAVE_PLTE;
|
| -
|
| - else if (chunk_name == png_IDAT)
|
| - {
|
| - png_ptr->idat_size = 0; /* It has been consumed */
|
| - break;
|
| - }
|
| - }
|
| -#endif
|
| - else if (chunk_name == png_PLTE)
|
| - png_handle_PLTE(png_ptr, info_ptr, length);
|
| -
|
| - else if (chunk_name == png_IDAT)
|
| - {
|
| - png_ptr->idat_size = length;
|
| - break;
|
| - }
|
| -
|
| -#ifdef PNG_READ_bKGD_SUPPORTED
|
| - else if (chunk_name == png_bKGD)
|
| - png_handle_bKGD(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_cHRM_SUPPORTED
|
| - else if (chunk_name == png_cHRM)
|
| - png_handle_cHRM(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_gAMA_SUPPORTED
|
| - else if (chunk_name == png_gAMA)
|
| - png_handle_gAMA(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_hIST_SUPPORTED
|
| - else if (chunk_name == png_hIST)
|
| - png_handle_hIST(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_oFFs_SUPPORTED
|
| - else if (chunk_name == png_oFFs)
|
| - png_handle_oFFs(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_pCAL_SUPPORTED
|
| - else if (chunk_name == png_pCAL)
|
| - png_handle_pCAL(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_sCAL_SUPPORTED
|
| - else if (chunk_name == png_sCAL)
|
| - png_handle_sCAL(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_pHYs_SUPPORTED
|
| - else if (chunk_name == png_pHYs)
|
| - png_handle_pHYs(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_sBIT_SUPPORTED
|
| - else if (chunk_name == png_sBIT)
|
| - png_handle_sBIT(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_sRGB_SUPPORTED
|
| - else if (chunk_name == png_sRGB)
|
| - png_handle_sRGB(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_iCCP_SUPPORTED
|
| - else if (chunk_name == png_iCCP)
|
| - png_handle_iCCP(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_sPLT_SUPPORTED
|
| - else if (chunk_name == png_sPLT)
|
| - png_handle_sPLT(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_tEXt_SUPPORTED
|
| - else if (chunk_name == png_tEXt)
|
| - png_handle_tEXt(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_tIME_SUPPORTED
|
| - else if (chunk_name == png_tIME)
|
| - png_handle_tIME(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_tRNS_SUPPORTED
|
| - else if (chunk_name == png_tRNS)
|
| - png_handle_tRNS(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_zTXt_SUPPORTED
|
| - else if (chunk_name == png_zTXt)
|
| - png_handle_zTXt(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_iTXt_SUPPORTED
|
| - else if (chunk_name == png_iTXt)
|
| - png_handle_iTXt(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| - else
|
| - png_handle_unknown(png_ptr, info_ptr, length,
|
| - PNG_HANDLE_CHUNK_AS_DEFAULT);
|
| - }
|
| -}
|
| -#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
| -
|
| -/* Optional call to update the users info_ptr structure */
|
| -void PNGAPI
|
| -png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
|
| -{
|
| - png_debug(1, "in png_read_update_info");
|
| -
|
| - if (png_ptr != NULL)
|
| - {
|
| - if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
|
| - {
|
| - png_read_start_row(png_ptr);
|
| -
|
| -# ifdef PNG_READ_TRANSFORMS_SUPPORTED
|
| - png_read_transform_info(png_ptr, info_ptr);
|
| -# else
|
| - PNG_UNUSED(info_ptr)
|
| -# endif
|
| - }
|
| -
|
| - /* New in 1.6.0 this avoids the bug of doing the initializations twice */
|
| - else
|
| - png_app_error(png_ptr,
|
| - "png_read_update_info/png_start_read_image: duplicate call");
|
| - }
|
| -}
|
| -
|
| -#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| -/* 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_structrp png_ptr)
|
| -{
|
| - png_debug(1, "in png_start_read_image");
|
| -
|
| - if (png_ptr != NULL)
|
| - {
|
| - if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
|
| - png_read_start_row(png_ptr);
|
| -
|
| - /* New in 1.6.0 this avoids the bug of doing the initializations twice */
|
| - else
|
| - png_app_error(png_ptr,
|
| - "png_start_read_image/png_read_update_info: duplicate call");
|
| - }
|
| -}
|
| -#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
| -
|
| -#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| -void PNGAPI
|
| -png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
|
| -{
|
| - png_row_info row_info;
|
| -
|
| - if (png_ptr == NULL)
|
| - return;
|
| -
|
| - png_debug2(1, "in png_read_row (row %lu, pass %d)",
|
| - (unsigned long)png_ptr->row_number, png_ptr->pass);
|
| -
|
| - /* png_read_start_row sets the information (in particular iwidth) for this
|
| - * interlace pass.
|
| - */
|
| - if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
|
| - png_read_start_row(png_ptr);
|
| -
|
| - /* 1.5.6: row_info moved out of png_struct to a local here. */
|
| - row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
|
| - row_info.color_type = png_ptr->color_type;
|
| - row_info.bit_depth = png_ptr->bit_depth;
|
| - row_info.channels = png_ptr->channels;
|
| - row_info.pixel_depth = png_ptr->pixel_depth;
|
| - row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
|
| -
|
| - 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
|
| - }
|
| -
|
| -#ifdef PNG_READ_INTERLACING_SUPPORTED
|
| - /* If interlaced and we do not need a new row, combine row and return.
|
| - * Notice that the pixels we have from previous rows have been transformed
|
| - * already; we can only combine like with like (transformed or
|
| - * untransformed) and, because of the libpng API for interlaced images, this
|
| - * means we must transform before de-interlacing.
|
| - */
|
| - 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, 1/*display*/);
|
| - 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, 1/*display*/);
|
| -
|
| - 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, 1/*display*/);
|
| -
|
| - 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, 1/*display*/);
|
| -
|
| - 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, 1/*display*/);
|
| -
|
| - 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, 1/*display*/);
|
| -
|
| - png_read_finish_row(png_ptr);
|
| - return;
|
| - }
|
| - break;
|
| -
|
| - default:
|
| - 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");
|
| -
|
| - /* Fill the row with IDAT data: */
|
| - png_read_IDAT_data(png_ptr, png_ptr->row_buf, row_info.rowbytes + 1);
|
| -
|
| - if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
|
| - {
|
| - if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
|
| - png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
|
| - png_ptr->prev_row + 1, png_ptr->row_buf[0]);
|
| - else
|
| - png_error(png_ptr, "bad adaptive filter value");
|
| - }
|
| -
|
| - /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
|
| - * 1.5.6, while the buffer really is this big in current versions of libpng
|
| - * it may not be in the future, so this was changed just to copy the
|
| - * interlaced count:
|
| - */
|
| - memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
|
| -
|
| -#ifdef 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(&row_info, png_ptr->row_buf + 1);
|
| - }
|
| -#endif
|
| -
|
| -
|
| -#ifdef PNG_READ_TRANSFORMS_SUPPORTED
|
| - if (png_ptr->transformations)
|
| - png_do_read_transformations(png_ptr, &row_info);
|
| -#endif
|
| -
|
| - /* The transformed pixel depth should match the depth now in row_info. */
|
| - if (png_ptr->transformed_pixel_depth == 0)
|
| - {
|
| - png_ptr->transformed_pixel_depth = row_info.pixel_depth;
|
| - if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
|
| - png_error(png_ptr, "sequential row overflow");
|
| - }
|
| -
|
| - else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
|
| - png_error(png_ptr, "internal sequential row size calculation error");
|
| -
|
| -#ifdef 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)
|
| - png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
|
| - png_ptr->transformations);
|
| -
|
| - if (dsp_row != NULL)
|
| - png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
| -
|
| - if (row != NULL)
|
| - png_combine_row(png_ptr, row, 0/*row*/);
|
| - }
|
| -
|
| - else
|
| -#endif
|
| - {
|
| - if (row != NULL)
|
| - png_combine_row(png_ptr, row, -1/*ignored*/);
|
| -
|
| - if (dsp_row != NULL)
|
| - png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
|
| - }
|
| - 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);
|
| -
|
| -}
|
| -#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
| -
|
| -#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| -/* 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 this version of libpng
|
| - */
|
| -
|
| -void PNGAPI
|
| -png_read_rows(png_structrp 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");
|
| -
|
| - if (png_ptr == NULL)
|
| - return;
|
| -
|
| - 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++;
|
| - }
|
| -}
|
| -#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
| -
|
| -#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| -/* 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 this version of libpng
|
| - */
|
| -void PNGAPI
|
| -png_read_image(png_structrp png_ptr, png_bytepp image)
|
| -{
|
| - png_uint_32 i, image_height;
|
| - int pass, j;
|
| - png_bytepp rp;
|
| -
|
| - png_debug(1, "in png_read_image");
|
| -
|
| - if (png_ptr == NULL)
|
| - return;
|
| -
|
| -#ifdef PNG_READ_INTERLACING_SUPPORTED
|
| - if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
|
| - {
|
| - pass = png_set_interlace_handling(png_ptr);
|
| - /* And make sure transforms are initialized. */
|
| - png_start_read_image(png_ptr);
|
| - }
|
| - else
|
| - {
|
| - if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE))
|
| - {
|
| - /* Caller called png_start_read_image or png_read_update_info without
|
| - * first turning on the PNG_INTERLACE transform. We can fix this here,
|
| - * but the caller should do it!
|
| - */
|
| - png_warning(png_ptr, "Interlace handling should be turned on when "
|
| - "using png_read_image");
|
| - /* Make sure this is set correctly */
|
| - png_ptr->num_rows = png_ptr->height;
|
| - }
|
| -
|
| - /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
|
| - * the above error case.
|
| - */
|
| - 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;
|
| -
|
| - for (j = 0; j < pass; j++)
|
| - {
|
| - rp = image;
|
| - for (i = 0; i < image_height; i++)
|
| - {
|
| - png_read_row(png_ptr, *rp, NULL);
|
| - rp++;
|
| - }
|
| - }
|
| -}
|
| -#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
| -
|
| -#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| -/* 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_structrp png_ptr, png_inforp info_ptr)
|
| -{
|
| -#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| - int keep;
|
| -#endif
|
| -
|
| - png_debug(1, "in png_read_end");
|
| -
|
| - if (png_ptr == NULL)
|
| - return;
|
| -
|
| - /* If png_read_end is called in the middle of reading the rows there may
|
| - * still be pending IDAT data and an owned zstream. Deal with this here.
|
| - */
|
| -#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| - if (!png_chunk_unknown_handling(png_ptr, png_IDAT))
|
| -#endif
|
| - png_read_finish_IDAT(png_ptr);
|
| -
|
| -#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
|
| - /* Report invalid palette index; added at libng-1.5.10 */
|
| - if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
|
| - png_ptr->num_palette_max > png_ptr->num_palette)
|
| - png_benign_error(png_ptr, "Read palette index exceeding num_palette");
|
| -#endif
|
| -
|
| - do
|
| - {
|
| - png_uint_32 length = png_read_chunk_header(png_ptr);
|
| - png_uint_32 chunk_name = png_ptr->chunk_name;
|
| -
|
| - if (chunk_name == png_IHDR)
|
| - png_handle_IHDR(png_ptr, info_ptr, length);
|
| -
|
| - else if (chunk_name == png_IEND)
|
| - png_handle_IEND(png_ptr, info_ptr, length);
|
| -
|
| -#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| - else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
|
| - {
|
| - if (chunk_name == png_IDAT)
|
| - {
|
| - if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
|
| - png_benign_error(png_ptr, "Too many IDATs found");
|
| - }
|
| - png_handle_unknown(png_ptr, info_ptr, length, keep);
|
| - if (chunk_name == png_PLTE)
|
| - png_ptr->mode |= PNG_HAVE_PLTE;
|
| - }
|
| -#endif
|
| -
|
| - else if (chunk_name == png_IDAT)
|
| - {
|
| - /* 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_HAVE_CHUNK_AFTER_IDAT))
|
| - png_benign_error(png_ptr, "Too many IDATs found");
|
| -
|
| - png_crc_finish(png_ptr, length);
|
| - }
|
| - else if (chunk_name == png_PLTE)
|
| - png_handle_PLTE(png_ptr, info_ptr, length);
|
| -
|
| -#ifdef PNG_READ_bKGD_SUPPORTED
|
| - else if (chunk_name == png_bKGD)
|
| - png_handle_bKGD(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_cHRM_SUPPORTED
|
| - else if (chunk_name == png_cHRM)
|
| - png_handle_cHRM(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_gAMA_SUPPORTED
|
| - else if (chunk_name == png_gAMA)
|
| - png_handle_gAMA(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_hIST_SUPPORTED
|
| - else if (chunk_name == png_hIST)
|
| - png_handle_hIST(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_oFFs_SUPPORTED
|
| - else if (chunk_name == png_oFFs)
|
| - png_handle_oFFs(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_pCAL_SUPPORTED
|
| - else if (chunk_name == png_pCAL)
|
| - png_handle_pCAL(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_sCAL_SUPPORTED
|
| - else if (chunk_name == png_sCAL)
|
| - png_handle_sCAL(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_pHYs_SUPPORTED
|
| - else if (chunk_name == png_pHYs)
|
| - png_handle_pHYs(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_sBIT_SUPPORTED
|
| - else if (chunk_name == png_sBIT)
|
| - png_handle_sBIT(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_sRGB_SUPPORTED
|
| - else if (chunk_name == png_sRGB)
|
| - png_handle_sRGB(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_iCCP_SUPPORTED
|
| - else if (chunk_name == png_iCCP)
|
| - png_handle_iCCP(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_sPLT_SUPPORTED
|
| - else if (chunk_name == png_sPLT)
|
| - png_handle_sPLT(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_tEXt_SUPPORTED
|
| - else if (chunk_name == png_tEXt)
|
| - png_handle_tEXt(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_tIME_SUPPORTED
|
| - else if (chunk_name == png_tIME)
|
| - png_handle_tIME(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_tRNS_SUPPORTED
|
| - else if (chunk_name == png_tRNS)
|
| - png_handle_tRNS(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_zTXt_SUPPORTED
|
| - else if (chunk_name == png_zTXt)
|
| - png_handle_zTXt(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_iTXt_SUPPORTED
|
| - else if (chunk_name == png_iTXt)
|
| - png_handle_iTXt(png_ptr, info_ptr, length);
|
| -#endif
|
| -
|
| - else
|
| - png_handle_unknown(png_ptr, info_ptr, length,
|
| - PNG_HANDLE_CHUNK_AS_DEFAULT);
|
| - } while (!(png_ptr->mode & PNG_HAVE_IEND));
|
| -}
|
| -#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
| -
|
| -/* Free all memory used in the read struct */
|
| -static void
|
| -png_read_destroy(png_structrp png_ptr)
|
| -{
|
| - png_debug(1, "in png_read_destroy");
|
| -
|
| -#ifdef PNG_READ_GAMMA_SUPPORTED
|
| - png_destroy_gamma_table(png_ptr);
|
| -#endif
|
| -
|
| - png_free(png_ptr, png_ptr->big_row_buf);
|
| - png_free(png_ptr, png_ptr->big_prev_row);
|
| - png_free(png_ptr, png_ptr->read_buffer);
|
| -
|
| -#ifdef PNG_READ_QUANTIZE_SUPPORTED
|
| - png_free(png_ptr, png_ptr->palette_lookup);
|
| - png_free(png_ptr, png_ptr->quantize_index);
|
| -#endif
|
| -
|
| - if (png_ptr->free_me & PNG_FREE_PLTE)
|
| - png_zfree(png_ptr, png_ptr->palette);
|
| - png_ptr->free_me &= ~PNG_FREE_PLTE;
|
| -
|
| -#if defined(PNG_tRNS_SUPPORTED) || \
|
| - defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
|
| - if (png_ptr->free_me & PNG_FREE_TRNS)
|
| - png_free(png_ptr, png_ptr->trans_alpha);
|
| - png_ptr->free_me &= ~PNG_FREE_TRNS;
|
| -#endif
|
| -
|
| - inflateEnd(&png_ptr->zstream);
|
| -
|
| -#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
|
| - png_free(png_ptr, png_ptr->save_buffer);
|
| -#endif
|
| -
|
| -#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) &&\
|
| - defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
|
| - png_free(png_ptr, png_ptr->unknown_chunk.data);
|
| -#endif
|
| -
|
| -#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
|
| - png_free(png_ptr, png_ptr->chunk_list);
|
| -#endif
|
| -
|
| - /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error
|
| - * callbacks are still set at this point. They are required to complete the
|
| - * destruction of the png_struct itself.
|
| - */
|
| -}
|
| -
|
| -/* 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_structrp png_ptr = NULL;
|
| -
|
| - png_debug(1, "in png_destroy_read_struct");
|
| -
|
| - if (png_ptr_ptr != NULL)
|
| - png_ptr = *png_ptr_ptr;
|
| -
|
| - if (png_ptr == NULL)
|
| - return;
|
| -
|
| - /* libpng 1.6.0: use the API to destroy info structs to ensure consistent
|
| - * behavior. Prior to 1.6.0 libpng did extra 'info' destruction in this API.
|
| - * The extra was, apparently, unnecessary yet this hides memory leak bugs.
|
| - */
|
| - png_destroy_info_struct(png_ptr, end_info_ptr_ptr);
|
| - png_destroy_info_struct(png_ptr, info_ptr_ptr);
|
| -
|
| - *png_ptr_ptr = NULL;
|
| - png_read_destroy(png_ptr);
|
| - png_destroy_png_struct(png_ptr);
|
| -}
|
| -
|
| -void PNGAPI
|
| -png_set_read_status_fn(png_structrp png_ptr, png_read_status_ptr read_row_fn)
|
| -{
|
| - if (png_ptr == NULL)
|
| - return;
|
| -
|
| - png_ptr->read_row_fn = read_row_fn;
|
| -}
|
| -
|
| -
|
| -#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| -#ifdef PNG_INFO_IMAGE_SUPPORTED
|
| -void PNGAPI
|
| -png_read_png(png_structrp png_ptr, png_inforp info_ptr,
|
| - int transforms,
|
| - voidp params)
|
| -{
|
| - int row;
|
| -
|
| - if (png_ptr == NULL || info_ptr == NULL)
|
| - return;
|
| -
|
| - /* 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);
|
| - if (info_ptr->height > PNG_UINT_32_MAX/(sizeof (png_bytep)))
|
| - png_error(png_ptr, "Image is too high to process with png_read_png()");
|
| -
|
| - /* -------------- image transformations start here ------------------- */
|
| -
|
| -#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
|
| - /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
|
| - */
|
| - if (transforms & PNG_TRANSFORM_SCALE_16)
|
| - {
|
| - /* Added at libpng-1.5.4. "strip_16" produces the same result that it
|
| - * did in earlier versions, while "scale_16" is now more accurate.
|
| - */
|
| - png_set_scale_16(png_ptr);
|
| - }
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
|
| - /* If both SCALE and STRIP are required pngrtran will effectively cancel the
|
| - * latter by doing SCALE first. This is ok and allows apps not to check for
|
| - * which is supported to get the right answer.
|
| - */
|
| - if (transforms & PNG_TRANSFORM_STRIP_16)
|
| - png_set_strip_16(png_ptr);
|
| -#endif
|
| -
|
| -#ifdef 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, or 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
|
| -
|
| -#ifdef 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
|
| -
|
| -#ifdef 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 quantizing.
|
| - */
|
| -
|
| -#ifdef 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
|
| -
|
| -#ifdef 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
|
| -
|
| -#ifdef 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
|
| -
|
| -#ifdef 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
|
| -
|
| -#ifdef 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
|
| -
|
| -/* Added at libpng-1.2.41 */
|
| -#ifdef 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
|
| -
|
| -/* Added at libpng-1.2.41 */
|
| -#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
| - /* Expand grayscale image to RGB */
|
| - if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
|
| - png_set_gray_to_rgb(png_ptr);
|
| -#endif
|
| -
|
| -/* Added at libpng-1.5.4 */
|
| -#ifdef PNG_READ_EXPAND_16_SUPPORTED
|
| - if (transforms & PNG_TRANSFORM_EXPAND_16)
|
| - png_set_expand_16(png_ptr);
|
| -#endif
|
| -
|
| - /* We don't handle adding filler bytes */
|
| -
|
| - /* We use png_read_image and rely on that for interlace handling, but we also
|
| - * call png_read_update_info therefore must turn on interlace handling now:
|
| - */
|
| - (void)png_set_interlace_handling(png_ptr);
|
| -
|
| - /* 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 ------------------- */
|
| -
|
| - png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
|
| - if (info_ptr->row_pointers == NULL)
|
| - {
|
| - png_uint_32 iptr;
|
| -
|
| - info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
|
| - info_ptr->height * (sizeof (png_bytep)));
|
| - for (iptr=0; iptr<info_ptr->height; iptr++)
|
| - info_ptr->row_pointers[iptr] = NULL;
|
| -
|
| - info_ptr->free_me |= PNG_FREE_ROWS;
|
| -
|
| - 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);
|
| -
|
| - PNG_UNUSED(transforms) /* Quiet compiler warnings */
|
| - PNG_UNUSED(params)
|
| -
|
| -}
|
| -#endif /* PNG_INFO_IMAGE_SUPPORTED */
|
| -#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
| -
|
| -#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
|
| -/* SIMPLIFIED READ
|
| - *
|
| - * This code currently relies on the sequential reader, though it could easily
|
| - * be made to work with the progressive one.
|
| - */
|
| -/* Arguments to png_image_finish_read: */
|
| -
|
| -/* Encoding of PNG data (used by the color-map code) */
|
| -/* TODO: change these, dang, ANSI-C reserves the 'E' namespace. */
|
| -# define E_NOTSET 0 /* File encoding not yet known */
|
| -# define E_sRGB 1 /* 8-bit encoded to sRGB gamma */
|
| -# define E_LINEAR 2 /* 16-bit linear: not encoded, NOT pre-multiplied! */
|
| -# define E_FILE 3 /* 8-bit encoded to file gamma, not sRGB or linear */
|
| -# define E_LINEAR8 4 /* 8-bit linear: only from a file value */
|
| -
|
| -/* Color-map processing: after libpng has run on the PNG image further
|
| - * processing may be needed to conver the data to color-map indicies.
|
| - */
|
| -#define PNG_CMAP_NONE 0
|
| -#define PNG_CMAP_GA 1 /* Process GA data to a color-map with alpha */
|
| -#define PNG_CMAP_TRANS 2 /* Process GA data to a background index */
|
| -#define PNG_CMAP_RGB 3 /* Process RGB data */
|
| -#define PNG_CMAP_RGB_ALPHA 4 /* Process RGBA data */
|
| -
|
| -/* The following document where the background is for each processing case. */
|
| -#define PNG_CMAP_NONE_BACKGROUND 256
|
| -#define PNG_CMAP_GA_BACKGROUND 231
|
| -#define PNG_CMAP_TRANS_BACKGROUND 254
|
| -#define PNG_CMAP_RGB_BACKGROUND 256
|
| -#define PNG_CMAP_RGB_ALPHA_BACKGROUND 216
|
| -
|
| -typedef struct
|
| -{
|
| - /* Arguments: */
|
| - png_imagep image;
|
| - png_voidp buffer;
|
| - png_int_32 row_stride;
|
| - png_voidp colormap;
|
| - png_const_colorp background;
|
| - /* Local variables: */
|
| - png_voidp local_row;
|
| - png_voidp first_row;
|
| - ptrdiff_t row_bytes; /* step between rows */
|
| - int file_encoding; /* E_ values above */
|
| - png_fixed_point gamma_to_linear; /* For E_FILE, reciprocal of gamma */
|
| - int colormap_processing; /* PNG_CMAP_ values above */
|
| -} png_image_read_control;
|
| -
|
| -/* Do all the *safe* initialization - 'safe' means that png_error won't be
|
| - * called, so setting up the jmp_buf is not required. This means that anything
|
| - * called from here must *not* call png_malloc - it has to call png_malloc_warn
|
| - * instead so that control is returned safely back to this routine.
|
| - */
|
| -static int
|
| -png_image_read_init(png_imagep image)
|
| -{
|
| - if (image->opaque == NULL)
|
| - {
|
| - png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, image,
|
| - png_safe_error, png_safe_warning);
|
| -
|
| - /* And set the rest of the structure to NULL to ensure that the various
|
| - * fields are consistent.
|
| - */
|
| - memset(image, 0, (sizeof *image));
|
| - image->version = PNG_IMAGE_VERSION;
|
| -
|
| - if (png_ptr != NULL)
|
| - {
|
| - png_infop info_ptr = png_create_info_struct(png_ptr);
|
| -
|
| - if (info_ptr != NULL)
|
| - {
|
| - png_controlp control = png_voidcast(png_controlp,
|
| - png_malloc_warn(png_ptr, (sizeof *control)));
|
| -
|
| - if (control != NULL)
|
| - {
|
| - memset(control, 0, (sizeof *control));
|
| -
|
| - control->png_ptr = png_ptr;
|
| - control->info_ptr = info_ptr;
|
| - control->for_write = 0;
|
| -
|
| - image->opaque = control;
|
| - return 1;
|
| - }
|
| -
|
| - /* Error clean up */
|
| - png_destroy_info_struct(png_ptr, &info_ptr);
|
| - }
|
| -
|
| - png_destroy_read_struct(&png_ptr, NULL, NULL);
|
| - }
|
| -
|
| - return png_image_error(image, "png_image_read: out of memory");
|
| - }
|
| -
|
| - return png_image_error(image, "png_image_read: opaque pointer not NULL");
|
| -}
|
| -
|
| -/* Utility to find the base format of a PNG file from a png_struct. */
|
| -static png_uint_32
|
| -png_image_format(png_structrp png_ptr)
|
| -{
|
| - png_uint_32 format = 0;
|
| -
|
| - if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
|
| - format |= PNG_FORMAT_FLAG_COLOR;
|
| -
|
| - if (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)
|
| - format |= PNG_FORMAT_FLAG_ALPHA;
|
| -
|
| - /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS
|
| - * sets the png_struct fields; that's all we are interested in here. The
|
| - * precise interaction with an app call to png_set_tRNS and PNG file reading
|
| - * is unclear.
|
| - */
|
| - else if (png_ptr->num_trans > 0)
|
| - format |= PNG_FORMAT_FLAG_ALPHA;
|
| -
|
| - if (png_ptr->bit_depth == 16)
|
| - format |= PNG_FORMAT_FLAG_LINEAR;
|
| -
|
| - if (png_ptr->color_type & PNG_COLOR_MASK_PALETTE)
|
| - format |= PNG_FORMAT_FLAG_COLORMAP;
|
| -
|
| - return format;
|
| -}
|
| -
|
| -/* Is the given gamma significantly different from sRGB? The test is the same
|
| - * one used in pngrtran.c when deciding whether to do gamma correction. The
|
| - * arithmetic optimizes the division by using the fact that the inverse of the
|
| - * file sRGB gamma is 2.2
|
| - */
|
| -static int
|
| -png_gamma_not_sRGB(png_fixed_point g)
|
| -{
|
| - if (g < PNG_FP_1)
|
| - {
|
| - /* An uninitialized gamma is assumed to be sRGB for the simplified API. */
|
| - if (g == 0)
|
| - return 0;
|
| -
|
| - return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */);
|
| - }
|
| -
|
| - return 1;
|
| -}
|
| -
|
| -/* Do the main body of a 'png_image_begin_read' function; read the PNG file
|
| - * header and fill in all the information. This is executed in a safe context,
|
| - * unlike the init routine above.
|
| - */
|
| -static int
|
| -png_image_read_header(png_voidp argument)
|
| -{
|
| - png_imagep image = png_voidcast(png_imagep, argument);
|
| - png_structrp png_ptr = image->opaque->png_ptr;
|
| - png_inforp info_ptr = image->opaque->info_ptr;
|
| -
|
| - png_set_benign_errors(png_ptr, 1/*warn*/);
|
| - png_read_info(png_ptr, info_ptr);
|
| -
|
| - /* Do this the fast way; just read directly out of png_struct. */
|
| - image->width = png_ptr->width;
|
| - image->height = png_ptr->height;
|
| -
|
| - {
|
| - png_uint_32 format = png_image_format(png_ptr);
|
| -
|
| - image->format = format;
|
| -
|
| -#ifdef PNG_COLORSPACE_SUPPORTED
|
| - /* Does the colorspace match sRGB? If there is no color endpoint
|
| - * (colorant) information assume yes, otherwise require the
|
| - * 'ENDPOINTS_MATCHE_sRGB' colorspace flag to have been set. If the
|
| - * colorspace has been determined to be invalid ignore it.
|
| - */
|
| - if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && ((png_ptr->colorspace.flags
|
| - & (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB|
|
| - PNG_COLORSPACE_INVALID)) == PNG_COLORSPACE_HAVE_ENDPOINTS))
|
| - image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB;
|
| -#endif
|
| - }
|
| -
|
| - /* We need the maximum number of entries regardless of the format the
|
| - * application sets here.
|
| - */
|
| - {
|
| - png_uint_32 cmap_entries;
|
| -
|
| - switch (png_ptr->color_type)
|
| - {
|
| - case PNG_COLOR_TYPE_GRAY:
|
| - cmap_entries = 1U << png_ptr->bit_depth;
|
| - break;
|
| -
|
| - case PNG_COLOR_TYPE_PALETTE:
|
| - cmap_entries = png_ptr->num_palette;
|
| - break;
|
| -
|
| - default:
|
| - cmap_entries = 256;
|
| - break;
|
| - }
|
| -
|
| - if (cmap_entries > 256)
|
| - cmap_entries = 256;
|
| -
|
| - image->colormap_entries = cmap_entries;
|
| - }
|
| -
|
| - return 1;
|
| -}
|
| -
|
| -#ifdef PNG_STDIO_SUPPORTED
|
| -int PNGAPI
|
| -png_image_begin_read_from_stdio(png_imagep image, FILE* file)
|
| -{
|
| - if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
| - {
|
| - if (file != NULL)
|
| - {
|
| - if (png_image_read_init(image))
|
| - {
|
| - /* This is slightly evil, but png_init_io doesn't do anything other
|
| - * than this and we haven't changed the standard IO functions so
|
| - * this saves a 'safe' function.
|
| - */
|
| - image->opaque->png_ptr->io_ptr = file;
|
| - return png_safe_execute(image, png_image_read_header, image);
|
| - }
|
| - }
|
| -
|
| - else
|
| - return png_image_error(image,
|
| - "png_image_begin_read_from_stdio: invalid argument");
|
| - }
|
| -
|
| - else if (image != NULL)
|
| - return png_image_error(image,
|
| - "png_image_begin_read_from_stdio: incorrect PNG_IMAGE_VERSION");
|
| -
|
| - return 0;
|
| -}
|
| -
|
| -int PNGAPI
|
| -png_image_begin_read_from_file(png_imagep image, const char *file_name)
|
| -{
|
| - if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
| - {
|
| - if (file_name != NULL)
|
| - {
|
| - FILE *fp = fopen(file_name, "rb");
|
| -
|
| - if (fp != NULL)
|
| - {
|
| - if (png_image_read_init(image))
|
| - {
|
| - image->opaque->png_ptr->io_ptr = fp;
|
| - image->opaque->owned_file = 1;
|
| - return png_safe_execute(image, png_image_read_header, image);
|
| - }
|
| -
|
| - /* Clean up: just the opened file. */
|
| - (void)fclose(fp);
|
| - }
|
| -
|
| - else
|
| - return png_image_error(image, strerror(errno));
|
| - }
|
| -
|
| - else
|
| - return png_image_error(image,
|
| - "png_image_begin_read_from_file: invalid argument");
|
| - }
|
| -
|
| - else if (image != NULL)
|
| - return png_image_error(image,
|
| - "png_image_begin_read_from_file: incorrect PNG_IMAGE_VERSION");
|
| -
|
| - return 0;
|
| -}
|
| -#endif /* PNG_STDIO_SUPPORTED */
|
| -
|
| -static void PNGCBAPI
|
| -png_image_memory_read(png_structp png_ptr, png_bytep out, png_size_t need)
|
| -{
|
| - if (png_ptr != NULL)
|
| - {
|
| - png_imagep image = png_voidcast(png_imagep, png_ptr->io_ptr);
|
| - if (image != NULL)
|
| - {
|
| - png_controlp cp = image->opaque;
|
| - if (cp != NULL)
|
| - {
|
| - png_const_bytep memory = cp->memory;
|
| - png_size_t size = cp->size;
|
| -
|
| - if (memory != NULL && size >= need)
|
| - {
|
| - memcpy(out, memory, need);
|
| - cp->memory = memory + need;
|
| - cp->size = size - need;
|
| - return;
|
| - }
|
| -
|
| - png_error(png_ptr, "read beyond end of data");
|
| - }
|
| - }
|
| -
|
| - png_error(png_ptr, "invalid memory read");
|
| - }
|
| -}
|
| -
|
| -int PNGAPI png_image_begin_read_from_memory(png_imagep image,
|
| - png_const_voidp memory, png_size_t size)
|
| -{
|
| - if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
| - {
|
| - if (memory != NULL && size > 0)
|
| - {
|
| - if (png_image_read_init(image))
|
| - {
|
| - /* Now set the IO functions to read from the memory buffer and
|
| - * store it into io_ptr. Again do this in-place to avoid calling a
|
| - * libpng function that requires error handling.
|
| - */
|
| - image->opaque->memory = png_voidcast(png_const_bytep, memory);
|
| - image->opaque->size = size;
|
| - image->opaque->png_ptr->io_ptr = image;
|
| - image->opaque->png_ptr->read_data_fn = png_image_memory_read;
|
| -
|
| - return png_safe_execute(image, png_image_read_header, image);
|
| - }
|
| - }
|
| -
|
| - else
|
| - return png_image_error(image,
|
| - "png_image_begin_read_from_memory: invalid argument");
|
| - }
|
| -
|
| - else if (image != NULL)
|
| - return png_image_error(image,
|
| - "png_image_begin_read_from_memory: incorrect PNG_IMAGE_VERSION");
|
| -
|
| - return 0;
|
| -}
|
| -
|
| -/* Utility function to skip chunks that are not used by the simplified image
|
| - * read functions and an appropriate macro to call it.
|
| - */
|
| -#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| -static void
|
| -png_image_skip_unused_chunks(png_structrp png_ptr)
|
| -{
|
| - /* Prepare the reader to ignore all recognized chunks whose data will not
|
| - * be used, i.e., all chunks recognized by libpng except for those
|
| - * involved in basic image reading:
|
| - *
|
| - * IHDR, PLTE, IDAT, IEND
|
| - *
|
| - * Or image data handling:
|
| - *
|
| - * tRNS, bKGD, gAMA, cHRM, sRGB, iCCP and sBIT.
|
| - *
|
| - * This provides a small performance improvement and eliminates any
|
| - * potential vulnerability to security problems in the unused chunks.
|
| - */
|
| - {
|
| - static PNG_CONST png_byte chunks_to_process[] = {
|
| - 98, 75, 71, 68, '\0', /* bKGD */
|
| - 99, 72, 82, 77, '\0', /* cHRM */
|
| - 103, 65, 77, 65, '\0', /* gAMA */
|
| - 105, 67, 67, 80, '\0', /* iCCP */
|
| - 115, 66, 73, 84, '\0', /* sBIT */
|
| - 115, 82, 71, 66, '\0', /* sRGB */
|
| - };
|
| -
|
| - /* Ignore unknown chunks and all other chunks except for the
|
| - * IHDR, PLTE, tRNS, IDAT, and IEND chunks.
|
| - */
|
| - png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER,
|
| - NULL, -1);
|
| -
|
| - /* But do not ignore image data handling chunks */
|
| - png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT,
|
| - chunks_to_process, (sizeof chunks_to_process)/5);
|
| - }
|
| -}
|
| -
|
| -# define PNG_SKIP_CHUNKS(p) png_image_skip_unused_chunks(p)
|
| -#else
|
| -# define PNG_SKIP_CHUNKS(p) ((void)0)
|
| -#endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */
|
| -
|
| -/* The following macro gives the exact rounded answer for all values in the
|
| - * range 0..255 (it actually divides by 51.2, but the rounding still generates
|
| - * the correct numbers 0..5
|
| - */
|
| -#define PNG_DIV51(v8) (((v8) * 5 + 130) >> 8)
|
| -
|
| -/* Utility functions to make particular color-maps */
|
| -static void
|
| -set_file_encoding(png_image_read_control *display)
|
| -{
|
| - png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma;
|
| - if (png_gamma_significant(g))
|
| - {
|
| - if (png_gamma_not_sRGB(g))
|
| - {
|
| - display->file_encoding = E_FILE;
|
| - display->gamma_to_linear = png_reciprocal(g);
|
| - }
|
| -
|
| - else
|
| - display->file_encoding = E_sRGB;
|
| - }
|
| -
|
| - else
|
| - display->file_encoding = E_LINEAR8;
|
| -}
|
| -
|
| -static unsigned int
|
| -decode_gamma(png_image_read_control *display, png_uint_32 value, int encoding)
|
| -{
|
| - if (encoding == E_FILE) /* double check */
|
| - encoding = display->file_encoding;
|
| -
|
| - if (encoding == E_NOTSET) /* must be the file encoding */
|
| - {
|
| - set_file_encoding(display);
|
| - encoding = display->file_encoding;
|
| - }
|
| -
|
| - switch (encoding)
|
| - {
|
| - case E_FILE:
|
| - value = png_gamma_16bit_correct(value*257, display->gamma_to_linear);
|
| - break;
|
| -
|
| - case E_sRGB:
|
| - value = png_sRGB_table[value];
|
| - break;
|
| -
|
| - case E_LINEAR:
|
| - break;
|
| -
|
| - case E_LINEAR8:
|
| - value *= 257;
|
| - break;
|
| -
|
| - default:
|
| - png_error(display->image->opaque->png_ptr,
|
| - "unexpected encoding (internal error)");
|
| - break;
|
| - }
|
| -
|
| - return value;
|
| -}
|
| -
|
| -static png_uint_32
|
| -png_colormap_compose(png_image_read_control *display,
|
| - png_uint_32 foreground, int foreground_encoding, png_uint_32 alpha,
|
| - png_uint_32 background, int encoding)
|
| -{
|
| - /* The file value is composed on the background, the background has the given
|
| - * encoding and so does the result, the file is encoded with E_FILE and the
|
| - * file and alpha are 8-bit values. The (output) encoding will always be
|
| - * E_LINEAR or E_sRGB.
|
| - */
|
| - png_uint_32 f = decode_gamma(display, foreground, foreground_encoding);
|
| - png_uint_32 b = decode_gamma(display, background, encoding);
|
| -
|
| - /* The alpha is always an 8-bit value (it comes from the palette), the value
|
| - * scaled by 255 is what PNG_sRGB_FROM_LINEAR requires.
|
| - */
|
| - f = f * alpha + b * (255-alpha);
|
| -
|
| - if (encoding == E_LINEAR)
|
| - {
|
| - /* Scale to 65535; divide by 255, approximately (in fact this is extremely
|
| - * accurate, it divides by 255.00000005937181414556, with no overflow.)
|
| - */
|
| - f *= 257; /* Now scaled by 65535 */
|
| - f += f >> 16;
|
| - f = (f+32768) >> 16;
|
| - }
|
| -
|
| - else /* E_sRGB */
|
| - f = PNG_sRGB_FROM_LINEAR(f);
|
| -
|
| - return f;
|
| -}
|
| -
|
| -/* NOTE: E_LINEAR values to this routine must be 16-bit, but E_FILE values must
|
| - * be 8-bit.
|
| - */
|
| -static void
|
| -png_create_colormap_entry(png_image_read_control *display,
|
| - png_uint_32 ip, png_uint_32 red, png_uint_32 green, png_uint_32 blue,
|
| - png_uint_32 alpha, int encoding)
|
| -{
|
| - png_imagep image = display->image;
|
| - const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) ?
|
| - E_LINEAR : E_sRGB;
|
| - const int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 &&
|
| - (red != green || green != blue);
|
| -
|
| - if (ip > 255)
|
| - png_error(image->opaque->png_ptr, "color-map index out of range");
|
| -
|
| - /* Update the cache with whether the file gamma is significantly different
|
| - * from sRGB.
|
| - */
|
| - if (encoding == E_FILE)
|
| - {
|
| - if (display->file_encoding == E_NOTSET)
|
| - set_file_encoding(display);
|
| -
|
| - /* Note that the cached value may be E_FILE too, but if it is then the
|
| - * gamma_to_linear member has been set.
|
| - */
|
| - encoding = display->file_encoding;
|
| - }
|
| -
|
| - if (encoding == E_FILE)
|
| - {
|
| - png_fixed_point g = display->gamma_to_linear;
|
| -
|
| - red = png_gamma_16bit_correct(red*257, g);
|
| - green = png_gamma_16bit_correct(green*257, g);
|
| - blue = png_gamma_16bit_correct(blue*257, g);
|
| -
|
| - if (convert_to_Y || output_encoding == E_LINEAR)
|
| - {
|
| - alpha *= 257;
|
| - encoding = E_LINEAR;
|
| - }
|
| -
|
| - else
|
| - {
|
| - red = PNG_sRGB_FROM_LINEAR(red * 255);
|
| - green = PNG_sRGB_FROM_LINEAR(green * 255);
|
| - blue = PNG_sRGB_FROM_LINEAR(blue * 255);
|
| - encoding = E_sRGB;
|
| - }
|
| - }
|
| -
|
| - else if (encoding == E_LINEAR8)
|
| - {
|
| - /* This encoding occurs quite frequently in test cases because PngSuite
|
| - * includes a gAMA 1.0 chunk with most images.
|
| - */
|
| - red *= 257;
|
| - green *= 257;
|
| - blue *= 257;
|
| - alpha *= 257;
|
| - encoding = E_LINEAR;
|
| - }
|
| -
|
| - else if (encoding == E_sRGB && (convert_to_Y || output_encoding == E_LINEAR))
|
| - {
|
| - /* The values are 8-bit sRGB values, but must be converted to 16-bit
|
| - * linear.
|
| - */
|
| - red = png_sRGB_table[red];
|
| - green = png_sRGB_table[green];
|
| - blue = png_sRGB_table[blue];
|
| - alpha *= 257;
|
| - encoding = E_LINEAR;
|
| - }
|
| -
|
| - /* This is set if the color isn't gray but the output is. */
|
| - if (encoding == E_LINEAR)
|
| - {
|
| - if (convert_to_Y)
|
| - {
|
| - /* NOTE: these values are copied from png_do_rgb_to_gray */
|
| - png_uint_32 y = (png_uint_32)6968 * red + (png_uint_32)23434 * green +
|
| - (png_uint_32)2366 * blue;
|
| -
|
| - if (output_encoding == E_LINEAR)
|
| - y = (y + 16384) >> 15;
|
| -
|
| - else
|
| - {
|
| - /* y is scaled by 32768, we need it scaled by 255: */
|
| - y = (y + 128) >> 8;
|
| - y *= 255;
|
| - y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7);
|
| - encoding = E_sRGB;
|
| - }
|
| -
|
| - blue = red = green = y;
|
| - }
|
| -
|
| - else if (output_encoding == E_sRGB)
|
| - {
|
| - red = PNG_sRGB_FROM_LINEAR(red * 255);
|
| - green = PNG_sRGB_FROM_LINEAR(green * 255);
|
| - blue = PNG_sRGB_FROM_LINEAR(blue * 255);
|
| - alpha = PNG_DIV257(alpha);
|
| - encoding = E_sRGB;
|
| - }
|
| - }
|
| -
|
| - if (encoding != output_encoding)
|
| - png_error(image->opaque->png_ptr, "bad encoding (internal error)");
|
| -
|
| - /* Store the value. */
|
| - {
|
| -# ifdef PNG_FORMAT_BGR_SUPPORTED
|
| - const int afirst = (image->format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
|
| - (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
|
| -# else
|
| -# define afirst 0
|
| -# endif
|
| -# ifdef PNG_FORMAT_BGR_SUPPORTED
|
| - const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) ? 2 : 0;
|
| -# else
|
| -# define bgr 0
|
| -# endif
|
| -
|
| - if (output_encoding == E_LINEAR)
|
| - {
|
| - png_uint_16p entry = png_voidcast(png_uint_16p, display->colormap);
|
| -
|
| - entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
|
| -
|
| - /* The linear 16-bit values must be pre-multiplied by the alpha channel
|
| - * value, if less than 65535 (this is, effectively, composite on black
|
| - * if the alpha channel is removed.)
|
| - */
|
| - switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
|
| - {
|
| - case 4:
|
| - entry[afirst ? 0 : 3] = (png_uint_16)alpha;
|
| - /* FALL THROUGH */
|
| -
|
| - case 3:
|
| - if (alpha < 65535)
|
| - {
|
| - if (alpha > 0)
|
| - {
|
| - blue = (blue * alpha + 32767U)/65535U;
|
| - green = (green * alpha + 32767U)/65535U;
|
| - red = (red * alpha + 32767U)/65535U;
|
| - }
|
| -
|
| - else
|
| - red = green = blue = 0;
|
| - }
|
| - entry[afirst + (2 ^ bgr)] = (png_uint_16)blue;
|
| - entry[afirst + 1] = (png_uint_16)green;
|
| - entry[afirst + bgr] = (png_uint_16)red;
|
| - break;
|
| -
|
| - case 2:
|
| - entry[1 ^ afirst] = (png_uint_16)alpha;
|
| - /* FALL THROUGH */
|
| -
|
| - case 1:
|
| - if (alpha < 65535)
|
| - {
|
| - if (alpha > 0)
|
| - green = (green * alpha + 32767U)/65535U;
|
| -
|
| - else
|
| - green = 0;
|
| - }
|
| - entry[afirst] = (png_uint_16)green;
|
| - break;
|
| -
|
| - default:
|
| - break;
|
| - }
|
| - }
|
| -
|
| - else /* output encoding is E_sRGB */
|
| - {
|
| - png_bytep entry = png_voidcast(png_bytep, display->colormap);
|
| -
|
| - entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
|
| -
|
| - switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
|
| - {
|
| - case 4:
|
| - entry[afirst ? 0 : 3] = (png_byte)alpha;
|
| - case 3:
|
| - entry[afirst + (2 ^ bgr)] = (png_byte)blue;
|
| - entry[afirst + 1] = (png_byte)green;
|
| - entry[afirst + bgr] = (png_byte)red;
|
| - break;
|
| -
|
| - case 2:
|
| - entry[1 ^ afirst] = (png_byte)alpha;
|
| - case 1:
|
| - entry[afirst] = (png_byte)green;
|
| - break;
|
| -
|
| - default:
|
| - break;
|
| - }
|
| - }
|
| -
|
| -# ifdef afirst
|
| -# undef afirst
|
| -# endif
|
| -# ifdef bgr
|
| -# undef bgr
|
| -# endif
|
| - }
|
| -}
|
| -
|
| -static int
|
| -make_gray_file_colormap(png_image_read_control *display)
|
| -{
|
| - unsigned int i;
|
| -
|
| - for (i=0; i<256; ++i)
|
| - png_create_colormap_entry(display, i, i, i, i, 255, E_FILE);
|
| -
|
| - return i;
|
| -}
|
| -
|
| -static int
|
| -make_gray_colormap(png_image_read_control *display)
|
| -{
|
| - unsigned int i;
|
| -
|
| - for (i=0; i<256; ++i)
|
| - png_create_colormap_entry(display, i, i, i, i, 255, E_sRGB);
|
| -
|
| - return i;
|
| -}
|
| -#define PNG_GRAY_COLORMAP_ENTRIES 256
|
| -
|
| -static int
|
| -make_ga_colormap(png_image_read_control *display)
|
| -{
|
| - unsigned int i, a;
|
| -
|
| - /* Alpha is retained, the output will be a color-map with entries
|
| - * selected by six levels of alpha. One transparent entry, 6 gray
|
| - * levels for all the intermediate alpha values, leaving 230 entries
|
| - * for the opaque grays. The color-map entries are the six values
|
| - * [0..5]*51, the GA processing uses PNG_DIV51(value) to find the
|
| - * relevant entry.
|
| - *
|
| - * if (alpha > 229) // opaque
|
| - * {
|
| - * // The 231 entries are selected to make the math below work:
|
| - * base = 0;
|
| - * entry = (231 * gray + 128) >> 8;
|
| - * }
|
| - * else if (alpha < 26) // transparent
|
| - * {
|
| - * base = 231;
|
| - * entry = 0;
|
| - * }
|
| - * else // partially opaque
|
| - * {
|
| - * base = 226 + 6 * PNG_DIV51(alpha);
|
| - * entry = PNG_DIV51(gray);
|
| - * }
|
| - */
|
| - i = 0;
|
| - while (i < 231)
|
| - {
|
| - unsigned int gray = (i * 256 + 115) / 231;
|
| - png_create_colormap_entry(display, i++, gray, gray, gray, 255, E_sRGB);
|
| - }
|
| -
|
| - /* 255 is used here for the component values for consistency with the code
|
| - * that undoes premultiplication in pngwrite.c.
|
| - */
|
| - png_create_colormap_entry(display, i++, 255, 255, 255, 0, E_sRGB);
|
| -
|
| - for (a=1; a<5; ++a)
|
| - {
|
| - unsigned int g;
|
| -
|
| - for (g=0; g<6; ++g)
|
| - png_create_colormap_entry(display, i++, g*51, g*51, g*51, a*51,
|
| - E_sRGB);
|
| - }
|
| -
|
| - return i;
|
| -}
|
| -
|
| -#define PNG_GA_COLORMAP_ENTRIES 256
|
| -
|
| -static int
|
| -make_rgb_colormap(png_image_read_control *display)
|
| -{
|
| - unsigned int i, r;
|
| -
|
| - /* Build a 6x6x6 opaque RGB cube */
|
| - for (i=r=0; r<6; ++r)
|
| - {
|
| - unsigned int g;
|
| -
|
| - for (g=0; g<6; ++g)
|
| - {
|
| - unsigned int b;
|
| -
|
| - for (b=0; b<6; ++b)
|
| - png_create_colormap_entry(display, i++, r*51, g*51, b*51, 255,
|
| - E_sRGB);
|
| - }
|
| - }
|
| -
|
| - return i;
|
| -}
|
| -
|
| -#define PNG_RGB_COLORMAP_ENTRIES 216
|
| -
|
| -/* Return a palette index to the above palette given three 8-bit sRGB values. */
|
| -#define PNG_RGB_INDEX(r,g,b) \
|
| - ((png_byte)(6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b)))
|
| -
|
| -static int
|
| -png_image_read_colormap(png_voidp argument)
|
| -{
|
| - png_image_read_control *display =
|
| - png_voidcast(png_image_read_control*, argument);
|
| - const png_imagep image = display->image;
|
| -
|
| - const png_structrp png_ptr = image->opaque->png_ptr;
|
| - const png_uint_32 output_format = image->format;
|
| - const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) ?
|
| - E_LINEAR : E_sRGB;
|
| -
|
| - unsigned int cmap_entries;
|
| - unsigned int output_processing; /* Output processing option */
|
| - unsigned int data_encoding = E_NOTSET; /* Encoding libpng must produce */
|
| -
|
| - /* Background information; the background color and the index of this color
|
| - * in the color-map if it exists (else 256).
|
| - */
|
| - unsigned int background_index = 256;
|
| - png_uint_32 back_r, back_g, back_b;
|
| -
|
| - /* Flags to accumulate things that need to be done to the input. */
|
| - int expand_tRNS = 0;
|
| -
|
| - /* Exclude the NYI feature of compositing onto a color-mapped buffer; it is
|
| - * very difficult to do, the results look awful, and it is difficult to see
|
| - * what possible use it is because the application can't control the
|
| - * color-map.
|
| - */
|
| - if (((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0 ||
|
| - png_ptr->num_trans > 0) /* alpha in input */ &&
|
| - ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) /* no alpha in output */)
|
| - {
|
| - if (output_encoding == E_LINEAR) /* compose on black */
|
| - back_b = back_g = back_r = 0;
|
| -
|
| - else if (display->background == NULL /* no way to remove it */)
|
| - png_error(png_ptr,
|
| - "a background color must be supplied to remove alpha/transparency");
|
| -
|
| - /* Get a copy of the background color (this avoids repeating the checks
|
| - * below.) The encoding is 8-bit sRGB or 16-bit linear, depending on the
|
| - * output format.
|
| - */
|
| - else
|
| - {
|
| - back_g = display->background->green;
|
| - if (output_format & PNG_FORMAT_FLAG_COLOR)
|
| - {
|
| - back_r = display->background->red;
|
| - back_b = display->background->blue;
|
| - }
|
| - else
|
| - back_b = back_r = back_g;
|
| - }
|
| - }
|
| -
|
| - else if (output_encoding == E_LINEAR)
|
| - back_b = back_r = back_g = 65535;
|
| -
|
| - else
|
| - back_b = back_r = back_g = 255;
|
| -
|
| - /* Default the input file gamma if required - this is necessary because
|
| - * libpng assumes that if no gamma information is present the data is in the
|
| - * output format, but the simplified API deduces the gamma from the input
|
| - * format.
|
| - */
|
| - if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) == 0)
|
| - {
|
| - /* Do this directly, not using the png_colorspace functions, to ensure
|
| - * that it happens even if the colorspace is invalid (though probably if
|
| - * it is the setting will be ignored) Note that the same thing can be
|
| - * achieved at the application interface with png_set_gAMA.
|
| - */
|
| - if (png_ptr->bit_depth == 16 &&
|
| - (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
|
| - png_ptr->colorspace.gamma = PNG_GAMMA_LINEAR;
|
| -
|
| - else
|
| - png_ptr->colorspace.gamma = PNG_GAMMA_sRGB_INVERSE;
|
| -
|
| - png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
|
| - }
|
| -
|
| - /* Decide what to do based on the PNG color type of the input data. The
|
| - * utility function png_create_colormap_entry deals with most aspects of the
|
| - * output transformations; this code works out how to produce bytes of
|
| - * color-map entries from the original format.
|
| - */
|
| - switch (png_ptr->color_type)
|
| - {
|
| - case PNG_COLOR_TYPE_GRAY:
|
| - if (png_ptr->bit_depth <= 8)
|
| - {
|
| - /* There at most 256 colors in the output, regardless of
|
| - * transparency.
|
| - */
|
| - unsigned int step, i, val, trans = 256/*ignore*/, back_alpha = 0;
|
| -
|
| - cmap_entries = 1U << png_ptr->bit_depth;
|
| - if (cmap_entries > image->colormap_entries)
|
| - png_error(png_ptr, "gray[8] color-map: too few entries");
|
| -
|
| - step = 255 / (cmap_entries - 1);
|
| - output_processing = PNG_CMAP_NONE;
|
| -
|
| - /* If there is a tRNS chunk then this either selects a transparent
|
| - * value or, if the output has no alpha, the background color.
|
| - */
|
| - if (png_ptr->num_trans > 0)
|
| - {
|
| - trans = png_ptr->trans_color.gray;
|
| -
|
| - if ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0)
|
| - back_alpha = output_encoding == E_LINEAR ? 65535 : 255;
|
| - }
|
| -
|
| - /* png_create_colormap_entry just takes an RGBA and writes the
|
| - * corresponding color-map entry using the format from 'image',
|
| - * including the required conversion to sRGB or linear as
|
| - * appropriate. The input values are always either sRGB (if the
|
| - * gamma correction flag is 0) or 0..255 scaled file encoded values
|
| - * (if the function must gamma correct them).
|
| - */
|
| - for (i=val=0; i<cmap_entries; ++i, val += step)
|
| - {
|
| - /* 'i' is a file value. While this will result in duplicated
|
| - * entries for 8-bit non-sRGB encoded files it is necessary to
|
| - * have non-gamma corrected values to do tRNS handling.
|
| - */
|
| - if (i != trans)
|
| - png_create_colormap_entry(display, i, val, val, val, 255,
|
| - E_FILE/*8-bit with file gamma*/);
|
| -
|
| - /* Else this entry is transparent. The colors don't matter if
|
| - * there is an alpha channel (back_alpha == 0), but it does no
|
| - * harm to pass them in; the values are not set above so this
|
| - * passes in white.
|
| - *
|
| - * NOTE: this preserves the full precision of the application
|
| - * supplied background color when it is used.
|
| - */
|
| - else
|
| - png_create_colormap_entry(display, i, back_r, back_g, back_b,
|
| - back_alpha, output_encoding);
|
| - }
|
| -
|
| - /* We need libpng to preserve the original encoding. */
|
| - data_encoding = E_FILE;
|
| -
|
| - /* The rows from libpng, while technically gray values, are now also
|
| - * color-map indicies; however, they may need to be expanded to 1
|
| - * byte per pixel. This is what png_set_packing does (i.e., it
|
| - * unpacks the bit values into bytes.)
|
| - */
|
| - if (png_ptr->bit_depth < 8)
|
| - png_set_packing(png_ptr);
|
| - }
|
| -
|
| - else /* bit depth is 16 */
|
| - {
|
| - /* The 16-bit input values can be converted directly to 8-bit gamma
|
| - * encoded values; however, if a tRNS chunk is present 257 color-map
|
| - * entries are required. This means that the extra entry requires
|
| - * special processing; add an alpha channel, sacrifice gray level
|
| - * 254 and convert transparent (alpha==0) entries to that.
|
| - *
|
| - * Use libpng to chop the data to 8 bits. Convert it to sRGB at the
|
| - * same time to minimize quality loss. If a tRNS chunk is present
|
| - * this means libpng must handle it too; otherwise it is impossible
|
| - * to do the exact match on the 16-bit value.
|
| - *
|
| - * If the output has no alpha channel *and* the background color is
|
| - * gray then it is possible to let libpng handle the substitution by
|
| - * ensuring that the corresponding gray level matches the background
|
| - * color exactly.
|
| - */
|
| - data_encoding = E_sRGB;
|
| -
|
| - if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
| - png_error(png_ptr, "gray[16] color-map: too few entries");
|
| -
|
| - cmap_entries = make_gray_colormap(display);
|
| -
|
| - if (png_ptr->num_trans > 0)
|
| - {
|
| - unsigned int back_alpha;
|
| -
|
| - if (output_format & PNG_FORMAT_FLAG_ALPHA)
|
| - back_alpha = 0;
|
| -
|
| - else
|
| - {
|
| - if (back_r == back_g && back_g == back_b)
|
| - {
|
| - /* Background is gray; no special processing will be
|
| - * required.
|
| - */
|
| - png_color_16 c;
|
| - png_uint_32 gray = back_g;
|
| -
|
| - if (output_encoding == E_LINEAR)
|
| - {
|
| - gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
| -
|
| - /* And make sure the corresponding palette entry
|
| - * matches.
|
| - */
|
| - png_create_colormap_entry(display, gray, back_g, back_g,
|
| - back_g, 65535, E_LINEAR);
|
| - }
|
| -
|
| - /* The background passed to libpng, however, must be the
|
| - * sRGB value.
|
| - */
|
| - c.index = 0; /*unused*/
|
| - c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
| -
|
| - /* NOTE: does this work without expanding tRNS to alpha?
|
| - * It should be the color->gray case below apparently
|
| - * doesn't.
|
| - */
|
| - png_set_background_fixed(png_ptr, &c,
|
| - PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
| - 0/*gamma: not used*/);
|
| -
|
| - output_processing = PNG_CMAP_NONE;
|
| - break;
|
| - }
|
| -
|
| - back_alpha = output_encoding == E_LINEAR ? 65535 : 255;
|
| - }
|
| -
|
| - /* output_processing means that the libpng-processed row will be
|
| - * 8-bit GA and it has to be processing to single byte color-map
|
| - * values. Entry 254 is replaced by either a completely
|
| - * transparent entry or by the background color at full
|
| - * precision (and the background color is not a simple gray leve
|
| - * in this case.)
|
| - */
|
| - expand_tRNS = 1;
|
| - output_processing = PNG_CMAP_TRANS;
|
| - background_index = 254;
|
| -
|
| - /* And set (overwrite) color-map entry 254 to the actual
|
| - * background color at full precision.
|
| - */
|
| - png_create_colormap_entry(display, 254, back_r, back_g, back_b,
|
| - back_alpha, output_encoding);
|
| - }
|
| -
|
| - else
|
| - output_processing = PNG_CMAP_NONE;
|
| - }
|
| - break;
|
| -
|
| - case PNG_COLOR_TYPE_GRAY_ALPHA:
|
| - /* 8-bit or 16-bit PNG with two channels - gray and alpha. A minimum
|
| - * of 65536 combinations. If, however, the alpha channel is to be
|
| - * removed there are only 256 possibilities if the background is gray.
|
| - * (Otherwise there is a subset of the 65536 possibilities defined by
|
| - * the triangle between black, white and the background color.)
|
| - *
|
| - * Reduce 16-bit files to 8-bit and sRGB encode the result. No need to
|
| - * worry about tRNS matching - tRNS is ignored if there is an alpha
|
| - * channel.
|
| - */
|
| - data_encoding = E_sRGB;
|
| -
|
| - if (output_format & PNG_FORMAT_FLAG_ALPHA)
|
| - {
|
| - if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
| - png_error(png_ptr, "gray+alpha color-map: too few entries");
|
| -
|
| - cmap_entries = make_ga_colormap(display);
|
| -
|
| - background_index = PNG_CMAP_GA_BACKGROUND;
|
| - output_processing = PNG_CMAP_GA;
|
| - }
|
| -
|
| - else /* alpha is removed */
|
| - {
|
| - /* Alpha must be removed as the PNG data is processed when the
|
| - * background is a color because the G and A channels are
|
| - * independent and the vector addition (non-parallel vectors) is a
|
| - * 2-D problem.
|
| - *
|
| - * This can be reduced to the same algorithm as above by making a
|
| - * colormap containing gray levels (for the opaque grays), a
|
| - * background entry (for a transparent pixel) and a set of four six
|
| - * level color values, one set for each intermediate alpha value.
|
| - * See the comments in make_ga_colormap for how this works in the
|
| - * per-pixel processing.
|
| - *
|
| - * If the background is gray, however, we only need a 256 entry gray
|
| - * level color map. It is sufficient to make the entry generated
|
| - * for the background color be exactly the color specified.
|
| - */
|
| - if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0 ||
|
| - (back_r == back_g && back_g == back_b))
|
| - {
|
| - /* Background is gray; no special processing will be required. */
|
| - png_color_16 c;
|
| - png_uint_32 gray = back_g;
|
| -
|
| - if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
| - png_error(png_ptr, "gray-alpha color-map: too few entries");
|
| -
|
| - cmap_entries = make_gray_colormap(display);
|
| -
|
| - if (output_encoding == E_LINEAR)
|
| - {
|
| - gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
| -
|
| - /* And make sure the corresponding palette entry matches. */
|
| - png_create_colormap_entry(display, gray, back_g, back_g,
|
| - back_g, 65535, E_LINEAR);
|
| - }
|
| -
|
| - /* The background passed to libpng, however, must be the sRGB
|
| - * value.
|
| - */
|
| - c.index = 0; /*unused*/
|
| - c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
| -
|
| - png_set_background_fixed(png_ptr, &c,
|
| - PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
| - 0/*gamma: not used*/);
|
| -
|
| - output_processing = PNG_CMAP_NONE;
|
| - }
|
| -
|
| - else
|
| - {
|
| - png_uint_32 i, a;
|
| -
|
| - /* This is the same as png_make_ga_colormap, above, except that
|
| - * the entries are all opaque.
|
| - */
|
| - if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
| - png_error(png_ptr, "ga-alpha color-map: too few entries");
|
| -
|
| - i = 0;
|
| - while (i < 231)
|
| - {
|
| - png_uint_32 gray = (i * 256 + 115) / 231;
|
| - png_create_colormap_entry(display, i++, gray, gray, gray,
|
| - 255, E_sRGB);
|
| - }
|
| -
|
| - /* NOTE: this preserves the full precision of the application
|
| - * background color.
|
| - */
|
| - background_index = i;
|
| - png_create_colormap_entry(display, i++, back_r, back_g, back_b,
|
| - output_encoding == E_LINEAR ? 65535U : 255U, output_encoding);
|
| -
|
| - /* For non-opaque input composite on the sRGB background - this
|
| - * requires inverting the encoding for each component. The input
|
| - * is still converted to the sRGB encoding because this is a
|
| - * reasonable approximate to the logarithmic curve of human
|
| - * visual sensitivity, at least over the narrow range which PNG
|
| - * represents. Consequently 'G' is always sRGB encoded, while
|
| - * 'A' is linear. We need the linear background colors.
|
| - */
|
| - if (output_encoding == E_sRGB) /* else already linear */
|
| - {
|
| - /* This may produce a value not exactly matching the
|
| - * background, but that's ok because these numbers are only
|
| - * used when alpha != 0
|
| - */
|
| - back_r = png_sRGB_table[back_r];
|
| - back_g = png_sRGB_table[back_g];
|
| - back_b = png_sRGB_table[back_b];
|
| - }
|
| -
|
| - for (a=1; a<5; ++a)
|
| - {
|
| - unsigned int g;
|
| -
|
| - /* PNG_sRGB_FROM_LINEAR expects a 16-bit linear value scaled
|
| - * by an 8-bit alpha value (0..255).
|
| - */
|
| - png_uint_32 alpha = 51 * a;
|
| - png_uint_32 back_rx = (255-alpha) * back_r;
|
| - png_uint_32 back_gx = (255-alpha) * back_g;
|
| - png_uint_32 back_bx = (255-alpha) * back_b;
|
| -
|
| - for (g=0; g<6; ++g)
|
| - {
|
| - png_uint_32 gray = png_sRGB_table[g*51] * alpha;
|
| -
|
| - png_create_colormap_entry(display, i++,
|
| - PNG_sRGB_FROM_LINEAR(gray + back_rx),
|
| - PNG_sRGB_FROM_LINEAR(gray + back_gx),
|
| - PNG_sRGB_FROM_LINEAR(gray + back_bx), 255, E_sRGB);
|
| - }
|
| - }
|
| -
|
| - cmap_entries = i;
|
| - output_processing = PNG_CMAP_GA;
|
| - }
|
| - }
|
| - break;
|
| -
|
| - case PNG_COLOR_TYPE_RGB:
|
| - case PNG_COLOR_TYPE_RGB_ALPHA:
|
| - /* Exclude the case where the output is gray; we can always handle this
|
| - * with the cases above.
|
| - */
|
| - if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0)
|
| - {
|
| - /* The color-map will be grayscale, so we may as well convert the
|
| - * input RGB values to a simple grayscale and use the grayscale
|
| - * code above.
|
| - *
|
| - * NOTE: calling this apparently damages the recognition of the
|
| - * transparent color in background color handling; call
|
| - * png_set_tRNS_to_alpha before png_set_background_fixed.
|
| - */
|
| - png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, -1,
|
| - -1);
|
| - data_encoding = E_sRGB;
|
| -
|
| - /* The output will now be one or two 8-bit gray or gray+alpha
|
| - * channels. The more complex case arises when the input has alpha.
|
| - */
|
| - if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
| - png_ptr->num_trans > 0) &&
|
| - (output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| - {
|
| - /* Both input and output have an alpha channel, so no background
|
| - * processing is required; just map the GA bytes to the right
|
| - * color-map entry.
|
| - */
|
| - expand_tRNS = 1;
|
| -
|
| - if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
| - png_error(png_ptr, "rgb[ga] color-map: too few entries");
|
| -
|
| - cmap_entries = make_ga_colormap(display);
|
| - background_index = PNG_CMAP_GA_BACKGROUND;
|
| - output_processing = PNG_CMAP_GA;
|
| - }
|
| -
|
| - else
|
| - {
|
| - /* Either the input or the output has no alpha channel, so there
|
| - * will be no non-opaque pixels in the color-map; it will just be
|
| - * grayscale.
|
| - */
|
| - if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
| - png_error(png_ptr, "rgb[gray] color-map: too few entries");
|
| -
|
| - /* Ideally this code would use libpng to do the gamma correction,
|
| - * but if an input alpha channel is to be removed we will hit the
|
| - * libpng bug in gamma+compose+rgb-to-gray (the double gamma
|
| - * correction bug). Fix this by dropping the gamma correction in
|
| - * this case and doing it in the palette; this will result in
|
| - * duplicate palette entries, but that's better than the
|
| - * alternative of double gamma correction.
|
| - */
|
| - if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
| - png_ptr->num_trans > 0) &&
|
| - png_gamma_not_sRGB(png_ptr->colorspace.gamma))
|
| - {
|
| - cmap_entries = make_gray_file_colormap(display);
|
| - data_encoding = E_FILE;
|
| - }
|
| -
|
| - else
|
| - cmap_entries = make_gray_colormap(display);
|
| -
|
| - /* But if the input has alpha or transparency it must be removed
|
| - */
|
| - if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
| - png_ptr->num_trans > 0)
|
| - {
|
| - png_color_16 c;
|
| - png_uint_32 gray = back_g;
|
| -
|
| - /* We need to ensure that the application background exists in
|
| - * the colormap and that completely transparent pixels map to
|
| - * it. Achieve this simply by ensuring that the entry
|
| - * selected for the background really is the background color.
|
| - */
|
| - if (data_encoding == E_FILE) /* from the fixup above */
|
| - {
|
| - /* The app supplied a gray which is in output_encoding, we
|
| - * need to convert it to a value of the input (E_FILE)
|
| - * encoding then set this palette entry to the required
|
| - * output encoding.
|
| - */
|
| - if (output_encoding == E_sRGB)
|
| - gray = png_sRGB_table[gray]; /* now E_LINEAR */
|
| -
|
| - gray = PNG_DIV257(png_gamma_16bit_correct(gray,
|
| - png_ptr->colorspace.gamma)); /* now E_FILE */
|
| -
|
| - /* And make sure the corresponding palette entry contains
|
| - * exactly the required sRGB value.
|
| - */
|
| - png_create_colormap_entry(display, gray, back_g, back_g,
|
| - back_g, 0/*unused*/, output_encoding);
|
| - }
|
| -
|
| - else if (output_encoding == E_LINEAR)
|
| - {
|
| - gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
| -
|
| - /* And make sure the corresponding palette entry matches.
|
| - */
|
| - png_create_colormap_entry(display, gray, back_g, back_g,
|
| - back_g, 0/*unused*/, E_LINEAR);
|
| - }
|
| -
|
| - /* The background passed to libpng, however, must be the
|
| - * output (normally sRGB) value.
|
| - */
|
| - c.index = 0; /*unused*/
|
| - c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
| -
|
| - /* NOTE: the following is apparently a bug in libpng. Without
|
| - * it the transparent color recognition in
|
| - * png_set_background_fixed seems to go wrong.
|
| - */
|
| - expand_tRNS = 1;
|
| - png_set_background_fixed(png_ptr, &c,
|
| - PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
| - 0/*gamma: not used*/);
|
| - }
|
| -
|
| - output_processing = PNG_CMAP_NONE;
|
| - }
|
| - }
|
| -
|
| - else /* output is color */
|
| - {
|
| - /* We could use png_quantize here so long as there is no transparent
|
| - * color or alpha; png_quantize ignores alpha. Easier overall just
|
| - * to do it once and using PNG_DIV51 on the 6x6x6 reduced RGB cube.
|
| - * Consequently we always want libpng to produce sRGB data.
|
| - */
|
| - data_encoding = E_sRGB;
|
| -
|
| - /* Is there any transparency or alpha? */
|
| - if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
| - png_ptr->num_trans > 0)
|
| - {
|
| - /* Is there alpha in the output too? If so all four channels are
|
| - * processed into a special RGB cube with alpha support.
|
| - */
|
| - if (output_format & PNG_FORMAT_FLAG_ALPHA)
|
| - {
|
| - png_uint_32 r;
|
| -
|
| - if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
|
| - png_error(png_ptr, "rgb+alpha color-map: too few entries");
|
| -
|
| - cmap_entries = make_rgb_colormap(display);
|
| -
|
| - /* Add a transparent entry. */
|
| - png_create_colormap_entry(display, cmap_entries, 255, 255,
|
| - 255, 0, E_sRGB);
|
| -
|
| - /* This is stored as the background index for the processing
|
| - * algorithm.
|
| - */
|
| - background_index = cmap_entries++;
|
| -
|
| - /* Add 27 r,g,b entries each with alpha 0.5. */
|
| - for (r=0; r<256; r = (r << 1) | 0x7f)
|
| - {
|
| - png_uint_32 g;
|
| -
|
| - for (g=0; g<256; g = (g << 1) | 0x7f)
|
| - {
|
| - png_uint_32 b;
|
| -
|
| - /* This generates components with the values 0, 127 and
|
| - * 255
|
| - */
|
| - for (b=0; b<256; b = (b << 1) | 0x7f)
|
| - png_create_colormap_entry(display, cmap_entries++,
|
| - r, g, b, 128, E_sRGB);
|
| - }
|
| - }
|
| -
|
| - expand_tRNS = 1;
|
| - output_processing = PNG_CMAP_RGB_ALPHA;
|
| - }
|
| -
|
| - else
|
| - {
|
| - /* Alpha/transparency must be removed. The background must
|
| - * exist in the color map (achieved by setting adding it after
|
| - * the 666 color-map). If the standard processing code will
|
| - * pick up this entry automatically that's all that is
|
| - * required; libpng can be called to do the background
|
| - * processing.
|
| - */
|
| - unsigned int sample_size =
|
| - PNG_IMAGE_SAMPLE_SIZE(output_format);
|
| - png_uint_32 r, g, b; /* sRGB background */
|
| -
|
| - if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
|
| - png_error(png_ptr, "rgb-alpha color-map: too few entries");
|
| -
|
| - cmap_entries = make_rgb_colormap(display);
|
| -
|
| - png_create_colormap_entry(display, cmap_entries, back_r,
|
| - back_g, back_b, 0/*unused*/, output_encoding);
|
| -
|
| - if (output_encoding == E_LINEAR)
|
| - {
|
| - r = PNG_sRGB_FROM_LINEAR(back_r * 255);
|
| - g = PNG_sRGB_FROM_LINEAR(back_g * 255);
|
| - b = PNG_sRGB_FROM_LINEAR(back_b * 255);
|
| - }
|
| -
|
| - else
|
| - {
|
| - r = back_r;
|
| - g = back_g;
|
| - b = back_g;
|
| - }
|
| -
|
| - /* Compare the newly-created color-map entry with the one the
|
| - * PNG_CMAP_RGB algorithm will use. If the two entries don't
|
| - * match, add the new one and set this as the background
|
| - * index.
|
| - */
|
| - if (memcmp((png_const_bytep)display->colormap +
|
| - sample_size * cmap_entries,
|
| - (png_const_bytep)display->colormap +
|
| - sample_size * PNG_RGB_INDEX(r,g,b),
|
| - sample_size) != 0)
|
| - {
|
| - /* The background color must be added. */
|
| - background_index = cmap_entries++;
|
| -
|
| - /* Add 27 r,g,b entries each with created by composing with
|
| - * the background at alpha 0.5.
|
| - */
|
| - for (r=0; r<256; r = (r << 1) | 0x7f)
|
| - {
|
| - for (g=0; g<256; g = (g << 1) | 0x7f)
|
| - {
|
| - /* This generates components with the values 0, 127
|
| - * and 255
|
| - */
|
| - for (b=0; b<256; b = (b << 1) | 0x7f)
|
| - png_create_colormap_entry(display, cmap_entries++,
|
| - png_colormap_compose(display, r, E_sRGB, 128,
|
| - back_r, output_encoding),
|
| - png_colormap_compose(display, g, E_sRGB, 128,
|
| - back_g, output_encoding),
|
| - png_colormap_compose(display, b, E_sRGB, 128,
|
| - back_b, output_encoding),
|
| - 0/*unused*/, output_encoding);
|
| - }
|
| - }
|
| -
|
| - expand_tRNS = 1;
|
| - output_processing = PNG_CMAP_RGB_ALPHA;
|
| - }
|
| -
|
| - else /* background color is in the standard color-map */
|
| - {
|
| - png_color_16 c;
|
| -
|
| - c.index = 0; /*unused*/
|
| - c.red = (png_uint_16)back_r;
|
| - c.gray = c.green = (png_uint_16)back_g;
|
| - c.blue = (png_uint_16)back_b;
|
| -
|
| - png_set_background_fixed(png_ptr, &c,
|
| - PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
| - 0/*gamma: not used*/);
|
| -
|
| - output_processing = PNG_CMAP_RGB;
|
| - }
|
| - }
|
| - }
|
| -
|
| - else /* no alpha or transparency in the input */
|
| - {
|
| - /* Alpha in the output is irrelevant, simply map the opaque input
|
| - * pixels to the 6x6x6 color-map.
|
| - */
|
| - if (PNG_RGB_COLORMAP_ENTRIES > image->colormap_entries)
|
| - png_error(png_ptr, "rgb color-map: too few entries");
|
| -
|
| - cmap_entries = make_rgb_colormap(display);
|
| - output_processing = PNG_CMAP_RGB;
|
| - }
|
| - }
|
| - break;
|
| -
|
| - case PNG_COLOR_TYPE_PALETTE:
|
| - /* It's already got a color-map. It may be necessary to eliminate the
|
| - * tRNS entries though.
|
| - */
|
| - {
|
| - unsigned int num_trans = png_ptr->num_trans;
|
| - png_const_bytep trans = num_trans > 0 ? png_ptr->trans_alpha : NULL;
|
| - png_const_colorp colormap = png_ptr->palette;
|
| - const int do_background = trans != NULL &&
|
| - (output_format & PNG_FORMAT_FLAG_ALPHA) == 0;
|
| - unsigned int i;
|
| -
|
| - /* Just in case: */
|
| - if (trans == NULL)
|
| - num_trans = 0;
|
| -
|
| - output_processing = PNG_CMAP_NONE;
|
| - data_encoding = E_FILE; /* Don't change from color-map indicies */
|
| - cmap_entries = png_ptr->num_palette;
|
| - if (cmap_entries > 256)
|
| - cmap_entries = 256;
|
| -
|
| - if (cmap_entries > image->colormap_entries)
|
| - png_error(png_ptr, "palette color-map: too few entries");
|
| -
|
| - for (i=0; i < cmap_entries; ++i)
|
| - {
|
| - if (do_background && i < num_trans && trans[i] < 255)
|
| - {
|
| - if (trans[i] == 0)
|
| - png_create_colormap_entry(display, i, back_r, back_g,
|
| - back_b, 0, output_encoding);
|
| -
|
| - else
|
| - {
|
| - /* Must compose the PNG file color in the color-map entry
|
| - * on the sRGB color in 'back'.
|
| - */
|
| - png_create_colormap_entry(display, i,
|
| - png_colormap_compose(display, colormap[i].red, E_FILE,
|
| - trans[i], back_r, output_encoding),
|
| - png_colormap_compose(display, colormap[i].green, E_FILE,
|
| - trans[i], back_g, output_encoding),
|
| - png_colormap_compose(display, colormap[i].blue, E_FILE,
|
| - trans[i], back_b, output_encoding),
|
| - output_encoding == E_LINEAR ? trans[i] * 257U :
|
| - trans[i],
|
| - output_encoding);
|
| - }
|
| - }
|
| -
|
| - else
|
| - png_create_colormap_entry(display, i, colormap[i].red,
|
| - colormap[i].green, colormap[i].blue,
|
| - i < num_trans ? trans[i] : 255U, E_FILE/*8-bit*/);
|
| - }
|
| -
|
| - /* The PNG data may have indicies packed in fewer than 8 bits, it
|
| - * must be expanded if so.
|
| - */
|
| - if (png_ptr->bit_depth < 8)
|
| - png_set_packing(png_ptr);
|
| - }
|
| - break;
|
| -
|
| - default:
|
| - png_error(png_ptr, "invalid PNG color type");
|
| - /*NOT REACHED*/
|
| - break;
|
| - }
|
| -
|
| - /* Now deal with the output processing */
|
| - if (expand_tRNS && png_ptr->num_trans > 0 &&
|
| - (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
|
| - png_set_tRNS_to_alpha(png_ptr);
|
| -
|
| - switch (data_encoding)
|
| - {
|
| - default:
|
| - png_error(png_ptr, "bad data option (internal error)");
|
| - break;
|
| -
|
| - case E_sRGB:
|
| - /* Change to 8-bit sRGB */
|
| - png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, PNG_GAMMA_sRGB);
|
| - /* FALL THROUGH */
|
| -
|
| - case E_FILE:
|
| - if (png_ptr->bit_depth > 8)
|
| - png_set_scale_16(png_ptr);
|
| - break;
|
| - }
|
| -
|
| - if (cmap_entries > 256 || cmap_entries > image->colormap_entries)
|
| - png_error(png_ptr, "color map overflow (BAD internal error)");
|
| -
|
| - image->colormap_entries = cmap_entries;
|
| -
|
| - /* Double check using the recorded background index */
|
| - switch (output_processing)
|
| - {
|
| - case PNG_CMAP_NONE:
|
| - if (background_index != PNG_CMAP_NONE_BACKGROUND)
|
| - goto bad_background;
|
| - break;
|
| -
|
| - case PNG_CMAP_GA:
|
| - if (background_index != PNG_CMAP_GA_BACKGROUND)
|
| - goto bad_background;
|
| - break;
|
| -
|
| - case PNG_CMAP_TRANS:
|
| - if (background_index >= cmap_entries ||
|
| - background_index != PNG_CMAP_TRANS_BACKGROUND)
|
| - goto bad_background;
|
| - break;
|
| -
|
| - case PNG_CMAP_RGB:
|
| - if (background_index != PNG_CMAP_RGB_BACKGROUND)
|
| - goto bad_background;
|
| - break;
|
| -
|
| - case PNG_CMAP_RGB_ALPHA:
|
| - if (background_index != PNG_CMAP_RGB_ALPHA_BACKGROUND)
|
| - goto bad_background;
|
| - break;
|
| -
|
| - default:
|
| - png_error(png_ptr, "bad processing option (internal error)");
|
| -
|
| - bad_background:
|
| - png_error(png_ptr, "bad background index (internal error)");
|
| - }
|
| -
|
| - display->colormap_processing = output_processing;
|
| -
|
| - return 1/*ok*/;
|
| -}
|
| -
|
| -/* The final part of the color-map read called from png_image_finish_read. */
|
| -static int
|
| -png_image_read_and_map(png_voidp argument)
|
| -{
|
| - png_image_read_control *display = png_voidcast(png_image_read_control*,
|
| - argument);
|
| - png_imagep image = display->image;
|
| - png_structrp png_ptr = image->opaque->png_ptr;
|
| - int passes;
|
| -
|
| - /* Called when the libpng data must be transformed into the color-mapped
|
| - * form. There is a local row buffer in display->local and this routine must
|
| - * do the interlace handling.
|
| - */
|
| - switch (png_ptr->interlaced)
|
| - {
|
| - case PNG_INTERLACE_NONE:
|
| - passes = 1;
|
| - break;
|
| -
|
| - case PNG_INTERLACE_ADAM7:
|
| - passes = PNG_INTERLACE_ADAM7_PASSES;
|
| - break;
|
| -
|
| - default:
|
| - passes = 0;
|
| - png_error(png_ptr, "unknown interlace type");
|
| - }
|
| -
|
| - {
|
| - png_uint_32 height = image->height;
|
| - png_uint_32 width = image->width;
|
| - int proc = display->colormap_processing;
|
| - png_bytep first_row = png_voidcast(png_bytep, display->first_row);
|
| - ptrdiff_t step_row = display->row_bytes;
|
| - int pass;
|
| -
|
| - for (pass = 0; pass < passes; ++pass)
|
| - {
|
| - unsigned int startx, stepx, stepy;
|
| - png_uint_32 y;
|
| -
|
| - if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
| - {
|
| - /* The row may be empty for a short image: */
|
| - if (PNG_PASS_COLS(width, pass) == 0)
|
| - continue;
|
| -
|
| - startx = PNG_PASS_START_COL(pass);
|
| - stepx = PNG_PASS_COL_OFFSET(pass);
|
| - y = PNG_PASS_START_ROW(pass);
|
| - stepy = PNG_PASS_ROW_OFFSET(pass);
|
| - }
|
| -
|
| - else
|
| - {
|
| - y = 0;
|
| - startx = 0;
|
| - stepx = stepy = 1;
|
| - }
|
| -
|
| - for (; y<height; y += stepy)
|
| - {
|
| - png_bytep inrow = png_voidcast(png_bytep, display->local_row);
|
| - png_bytep outrow = first_row + y * step_row;
|
| - png_const_bytep end_row = outrow + width;
|
| -
|
| - /* Read read the libpng data into the temporary buffer. */
|
| - png_read_row(png_ptr, inrow, NULL);
|
| -
|
| - /* Now process the row according to the processing option, note
|
| - * that the caller verifies that the format of the libpng output
|
| - * data is as required.
|
| - */
|
| - outrow += startx;
|
| - switch (proc)
|
| - {
|
| - case PNG_CMAP_GA:
|
| - for (; outrow < end_row; outrow += stepx)
|
| - {
|
| - /* The data is always in the PNG order */
|
| - unsigned int gray = *inrow++;
|
| - unsigned int alpha = *inrow++;
|
| - unsigned int entry;
|
| -
|
| - /* NOTE: this code is copied as a comment in
|
| - * make_ga_colormap above. Please update the
|
| - * comment if you change this code!
|
| - */
|
| - if (alpha > 229) /* opaque */
|
| - {
|
| - entry = (231 * gray + 128) >> 8;
|
| - }
|
| - else if (alpha < 26) /* transparent */
|
| - {
|
| - entry = 231;
|
| - }
|
| - else /* partially opaque */
|
| - {
|
| - entry = 226 + 6 * PNG_DIV51(alpha) + PNG_DIV51(gray);
|
| - }
|
| -
|
| - *outrow = (png_byte)entry;
|
| - }
|
| - break;
|
| -
|
| - case PNG_CMAP_TRANS:
|
| - for (; outrow < end_row; outrow += stepx)
|
| - {
|
| - png_byte gray = *inrow++;
|
| - png_byte alpha = *inrow++;
|
| -
|
| - if (alpha == 0)
|
| - *outrow = PNG_CMAP_TRANS_BACKGROUND;
|
| -
|
| - else if (gray != PNG_CMAP_TRANS_BACKGROUND)
|
| - *outrow = gray;
|
| -
|
| - else
|
| - *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1);
|
| - }
|
| - break;
|
| -
|
| - case PNG_CMAP_RGB:
|
| - for (; outrow < end_row; outrow += stepx)
|
| - {
|
| - *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], inrow[2]);
|
| - inrow += 3;
|
| - }
|
| - break;
|
| -
|
| - case PNG_CMAP_RGB_ALPHA:
|
| - for (; outrow < end_row; outrow += stepx)
|
| - {
|
| - unsigned int alpha = inrow[3];
|
| -
|
| - /* Because the alpha entries only hold alpha==0.5 values
|
| - * split the processing at alpha==0.25 (64) and 0.75
|
| - * (196).
|
| - */
|
| -
|
| - if (alpha >= 196)
|
| - *outrow = PNG_RGB_INDEX(inrow[0], inrow[1],
|
| - inrow[2]);
|
| -
|
| - else if (alpha < 64)
|
| - *outrow = PNG_CMAP_RGB_ALPHA_BACKGROUND;
|
| -
|
| - else
|
| - {
|
| - /* Likewise there are three entries for each of r, g
|
| - * and b. We could select the entry by popcount on
|
| - * the top two bits on those architectures that
|
| - * support it, this is what the code below does,
|
| - * crudely.
|
| - */
|
| - unsigned int back_i = PNG_CMAP_RGB_ALPHA_BACKGROUND+1;
|
| -
|
| - /* Here are how the values map:
|
| - *
|
| - * 0x00 .. 0x3f -> 0
|
| - * 0x40 .. 0xbf -> 1
|
| - * 0xc0 .. 0xff -> 2
|
| - *
|
| - * So, as above with the explicit alpha checks, the
|
| - * breakpoints are at 64 and 196.
|
| - */
|
| - if (inrow[0] & 0x80) back_i += 9; /* red */
|
| - if (inrow[0] & 0x40) back_i += 9;
|
| - if (inrow[0] & 0x80) back_i += 3; /* green */
|
| - if (inrow[0] & 0x40) back_i += 3;
|
| - if (inrow[0] & 0x80) back_i += 1; /* blue */
|
| - if (inrow[0] & 0x40) back_i += 1;
|
| -
|
| - *outrow = (png_byte)back_i;
|
| - }
|
| -
|
| - inrow += 4;
|
| - }
|
| - break;
|
| -
|
| - default:
|
| - break;
|
| - }
|
| - }
|
| - }
|
| - }
|
| -
|
| - return 1;
|
| -}
|
| -
|
| -static int
|
| -png_image_read_colormapped(png_voidp argument)
|
| -{
|
| - png_image_read_control *display = png_voidcast(png_image_read_control*,
|
| - argument);
|
| - png_imagep image = display->image;
|
| - png_controlp control = image->opaque;
|
| - png_structrp png_ptr = control->png_ptr;
|
| - png_inforp info_ptr = control->info_ptr;
|
| -
|
| - int passes = 0; /* As a flag */
|
| -
|
| - PNG_SKIP_CHUNKS(png_ptr);
|
| -
|
| - /* Update the 'info' structure and make sure the result is as required; first
|
| - * make sure to turn on the interlace handling if it will be required
|
| - * (because it can't be turned on *after* the call to png_read_update_info!)
|
| - */
|
| - if (display->colormap_processing == PNG_CMAP_NONE)
|
| - passes = png_set_interlace_handling(png_ptr);
|
| -
|
| - png_read_update_info(png_ptr, info_ptr);
|
| -
|
| - /* The expected output can be deduced from the colormap_processing option. */
|
| - switch (display->colormap_processing)
|
| - {
|
| - case PNG_CMAP_NONE:
|
| - /* Output must be one channel and one byte per pixel, the output
|
| - * encoding can be anything.
|
| - */
|
| - if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
|
| - info_ptr->color_type == PNG_COLOR_TYPE_GRAY) &&
|
| - info_ptr->bit_depth == 8)
|
| - break;
|
| -
|
| - goto bad_output;
|
| -
|
| - case PNG_CMAP_TRANS:
|
| - case PNG_CMAP_GA:
|
| - /* Output must be two channels and the 'G' one must be sRGB, the latter
|
| - * can be checked with an exact number because it should have been set
|
| - * to this number above!
|
| - */
|
| - if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
|
| - info_ptr->bit_depth == 8 &&
|
| - png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
| - image->colormap_entries == 256)
|
| - break;
|
| -
|
| - goto bad_output;
|
| -
|
| - case PNG_CMAP_RGB:
|
| - /* Output must be 8-bit sRGB encoded RGB */
|
| - if (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
|
| - info_ptr->bit_depth == 8 &&
|
| - png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
| - image->colormap_entries == 216)
|
| - break;
|
| -
|
| - goto bad_output;
|
| -
|
| - case PNG_CMAP_RGB_ALPHA:
|
| - /* Output must be 8-bit sRGB encoded RGBA */
|
| - if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
|
| - info_ptr->bit_depth == 8 &&
|
| - png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
| - image->colormap_entries == 244 /* 216 + 1 + 27 */)
|
| - break;
|
| -
|
| - /* goto bad_output; */
|
| - /* FALL THROUGH */
|
| -
|
| - default:
|
| - bad_output:
|
| - png_error(png_ptr, "bad color-map processing (internal error)");
|
| - }
|
| -
|
| - /* Now read the rows. Do this here if it is possible to read directly into
|
| - * the output buffer, otherwise allocate a local row buffer of the maximum
|
| - * size libpng requires and call the relevant processing routine safely.
|
| - */
|
| - {
|
| - png_voidp first_row = display->buffer;
|
| - ptrdiff_t row_bytes = display->row_stride;
|
| -
|
| - /* The following expression is designed to work correctly whether it gives
|
| - * a signed or an unsigned result.
|
| - */
|
| - if (row_bytes < 0)
|
| - {
|
| - char *ptr = png_voidcast(char*, first_row);
|
| - ptr += (image->height-1) * (-row_bytes);
|
| - first_row = png_voidcast(png_voidp, ptr);
|
| - }
|
| -
|
| - display->first_row = first_row;
|
| - display->row_bytes = row_bytes;
|
| - }
|
| -
|
| - if (passes == 0)
|
| - {
|
| - int result;
|
| - png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
| -
|
| - display->local_row = row;
|
| - result = png_safe_execute(image, png_image_read_and_map, display);
|
| - display->local_row = NULL;
|
| - png_free(png_ptr, row);
|
| -
|
| - return result;
|
| - }
|
| -
|
| - else
|
| - {
|
| - png_alloc_size_t row_bytes = display->row_bytes;
|
| -
|
| - while (--passes >= 0)
|
| - {
|
| - png_uint_32 y = image->height;
|
| - png_bytep row = png_voidcast(png_bytep, display->first_row);
|
| -
|
| - while (y-- > 0)
|
| - {
|
| - png_read_row(png_ptr, row, NULL);
|
| - row += row_bytes;
|
| - }
|
| - }
|
| -
|
| - return 1;
|
| - }
|
| -}
|
| -
|
| -/* Just the row reading part of png_image_read. */
|
| -static int
|
| -png_image_read_composite(png_voidp argument)
|
| -{
|
| - png_image_read_control *display = png_voidcast(png_image_read_control*,
|
| - argument);
|
| - png_imagep image = display->image;
|
| - png_structrp png_ptr = image->opaque->png_ptr;
|
| - int passes;
|
| -
|
| - switch (png_ptr->interlaced)
|
| - {
|
| - case PNG_INTERLACE_NONE:
|
| - passes = 1;
|
| - break;
|
| -
|
| - case PNG_INTERLACE_ADAM7:
|
| - passes = PNG_INTERLACE_ADAM7_PASSES;
|
| - break;
|
| -
|
| - default:
|
| - passes = 0;
|
| - png_error(png_ptr, "unknown interlace type");
|
| - }
|
| -
|
| - {
|
| - png_uint_32 height = image->height;
|
| - png_uint_32 width = image->width;
|
| - ptrdiff_t step_row = display->row_bytes;
|
| - unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
|
| - int pass;
|
| -
|
| - for (pass = 0; pass < passes; ++pass)
|
| - {
|
| - unsigned int startx, stepx, stepy;
|
| - png_uint_32 y;
|
| -
|
| - if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
| - {
|
| - /* The row may be empty for a short image: */
|
| - if (PNG_PASS_COLS(width, pass) == 0)
|
| - continue;
|
| -
|
| - startx = PNG_PASS_START_COL(pass) * channels;
|
| - stepx = PNG_PASS_COL_OFFSET(pass) * channels;
|
| - y = PNG_PASS_START_ROW(pass);
|
| - stepy = PNG_PASS_ROW_OFFSET(pass);
|
| - }
|
| -
|
| - else
|
| - {
|
| - y = 0;
|
| - startx = 0;
|
| - stepx = channels;
|
| - stepy = 1;
|
| - }
|
| -
|
| - for (; y<height; y += stepy)
|
| - {
|
| - png_bytep inrow = png_voidcast(png_bytep, display->local_row);
|
| - png_bytep outrow;
|
| - png_const_bytep end_row;
|
| -
|
| - /* Read the row, which is packed: */
|
| - png_read_row(png_ptr, inrow, NULL);
|
| -
|
| - outrow = png_voidcast(png_bytep, display->first_row);
|
| - outrow += y * step_row;
|
| - end_row = outrow + width * channels;
|
| -
|
| - /* Now do the composition on each pixel in this row. */
|
| - outrow += startx;
|
| - for (; outrow < end_row; outrow += stepx)
|
| - {
|
| - png_byte alpha = inrow[channels];
|
| -
|
| - if (alpha > 0) /* else no change to the output */
|
| - {
|
| - unsigned int c;
|
| -
|
| - for (c=0; c<channels; ++c)
|
| - {
|
| - png_uint_32 component = inrow[c];
|
| -
|
| - if (alpha < 255) /* else just use component */
|
| - {
|
| - /* This is PNG_OPTIMIZED_ALPHA, the component value
|
| - * is a linear 8-bit value. Combine this with the
|
| - * current outrow[c] value which is sRGB encoded.
|
| - * Arithmetic here is 16-bits to preserve the output
|
| - * values correctly.
|
| - */
|
| - component *= 257*255; /* =65535 */
|
| - component += (255-alpha)*png_sRGB_table[outrow[c]];
|
| -
|
| - /* So 'component' is scaled by 255*65535 and is
|
| - * therefore appropriate for the sRGB to linear
|
| - * conversion table.
|
| - */
|
| - component = PNG_sRGB_FROM_LINEAR(component);
|
| - }
|
| -
|
| - outrow[c] = (png_byte)component;
|
| - }
|
| - }
|
| -
|
| - inrow += channels+1; /* components and alpha channel */
|
| - }
|
| - }
|
| - }
|
| - }
|
| -
|
| - return 1;
|
| -}
|
| -
|
| -/* The do_local_background case; called when all the following transforms are to
|
| - * be done:
|
| - *
|
| - * PNG_RGB_TO_GRAY
|
| - * PNG_COMPOSITE
|
| - * PNG_GAMMA
|
| - *
|
| - * This is a work-round for the fact that both the PNG_RGB_TO_GRAY and
|
| - * PNG_COMPOSITE code performs gamma correction, so we get double gamma
|
| - * correction. The fix-up is to prevent the PNG_COMPOSITE operation happening
|
| - * inside libpng, so this routine sees an 8 or 16-bit gray+alpha row and handles
|
| - * the removal or pre-multiplication of the alpha channel.
|
| - */
|
| -static int
|
| -png_image_read_background(png_voidp argument)
|
| -{
|
| - png_image_read_control *display = png_voidcast(png_image_read_control*,
|
| - argument);
|
| - png_imagep image = display->image;
|
| - png_structrp png_ptr = image->opaque->png_ptr;
|
| - png_inforp info_ptr = image->opaque->info_ptr;
|
| - png_uint_32 height = image->height;
|
| - png_uint_32 width = image->width;
|
| - int pass, passes;
|
| -
|
| - /* Double check the convoluted logic below. We expect to get here with
|
| - * libpng doing rgb to gray and gamma correction but background processing
|
| - * left to the png_image_read_background function. The rows libpng produce
|
| - * might be 8 or 16-bit but should always have two channels; gray plus alpha.
|
| - */
|
| - if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
|
| - png_error(png_ptr, "lost rgb to gray");
|
| -
|
| - if ((png_ptr->transformations & PNG_COMPOSE) != 0)
|
| - png_error(png_ptr, "unexpected compose");
|
| -
|
| - if (png_get_channels(png_ptr, info_ptr) != 2)
|
| - png_error(png_ptr, "lost/gained channels");
|
| -
|
| - /* Expect the 8-bit case to always remove the alpha channel */
|
| - if ((image->format & PNG_FORMAT_FLAG_LINEAR) == 0 &&
|
| - (image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| - png_error(png_ptr, "unexpected 8-bit transformation");
|
| -
|
| - switch (png_ptr->interlaced)
|
| - {
|
| - case PNG_INTERLACE_NONE:
|
| - passes = 1;
|
| - break;
|
| -
|
| - case PNG_INTERLACE_ADAM7:
|
| - passes = PNG_INTERLACE_ADAM7_PASSES;
|
| - break;
|
| -
|
| - default:
|
| - passes = 0;
|
| - png_error(png_ptr, "unknown interlace type");
|
| - }
|
| -
|
| - switch (png_get_bit_depth(png_ptr, info_ptr))
|
| - {
|
| - default:
|
| - png_error(png_ptr, "unexpected bit depth");
|
| - break;
|
| -
|
| - case 8:
|
| - /* 8-bit sRGB gray values with an alpha channel; the alpha channel is
|
| - * to be removed by composing on a backgroundi: either the row if
|
| - * display->background is NULL or display->background->green if not.
|
| - * Unlike the code above ALPHA_OPTIMIZED has *not* been done.
|
| - */
|
| - {
|
| - png_bytep first_row = png_voidcast(png_bytep, display->first_row);
|
| - ptrdiff_t step_row = display->row_bytes;
|
| -
|
| - for (pass = 0; pass < passes; ++pass)
|
| - {
|
| - png_bytep row = png_voidcast(png_bytep,
|
| - display->first_row);
|
| - unsigned int startx, stepx, stepy;
|
| - png_uint_32 y;
|
| -
|
| - if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
| - {
|
| - /* The row may be empty for a short image: */
|
| - if (PNG_PASS_COLS(width, pass) == 0)
|
| - continue;
|
| -
|
| - startx = PNG_PASS_START_COL(pass);
|
| - stepx = PNG_PASS_COL_OFFSET(pass);
|
| - y = PNG_PASS_START_ROW(pass);
|
| - stepy = PNG_PASS_ROW_OFFSET(pass);
|
| - }
|
| -
|
| - else
|
| - {
|
| - y = 0;
|
| - startx = 0;
|
| - stepx = stepy = 1;
|
| - }
|
| -
|
| - if (display->background == NULL)
|
| - {
|
| - for (; y<height; y += stepy)
|
| - {
|
| - png_bytep inrow = png_voidcast(png_bytep,
|
| - display->local_row);
|
| - png_bytep outrow = first_row + y * step_row;
|
| - png_const_bytep end_row = outrow + width;
|
| -
|
| - /* Read the row, which is packed: */
|
| - png_read_row(png_ptr, inrow, NULL);
|
| -
|
| - /* Now do the composition on each pixel in this row. */
|
| - outrow += startx;
|
| - for (; outrow < end_row; outrow += stepx)
|
| - {
|
| - png_byte alpha = inrow[1];
|
| -
|
| - if (alpha > 0) /* else no change to the output */
|
| - {
|
| - png_uint_32 component = inrow[0];
|
| -
|
| - if (alpha < 255) /* else just use component */
|
| - {
|
| - /* Since PNG_OPTIMIZED_ALPHA was not set it is
|
| - * necessary to invert the sRGB transfer
|
| - * function and multiply the alpha out.
|
| - */
|
| - component = png_sRGB_table[component] * alpha;
|
| - component += png_sRGB_table[outrow[0]] *
|
| - (255-alpha);
|
| - component = PNG_sRGB_FROM_LINEAR(component);
|
| - }
|
| -
|
| - outrow[0] = (png_byte)component;
|
| - }
|
| -
|
| - inrow += 2; /* gray and alpha channel */
|
| - }
|
| - }
|
| - }
|
| -
|
| - else /* constant background value */
|
| - {
|
| - png_byte background8 = display->background->green;
|
| - png_uint_16 background = png_sRGB_table[background8];
|
| -
|
| - for (; y<height; y += stepy)
|
| - {
|
| - png_bytep inrow = png_voidcast(png_bytep,
|
| - display->local_row);
|
| - png_bytep outrow = first_row + y * step_row;
|
| - png_const_bytep end_row = outrow + width;
|
| -
|
| - /* Read the row, which is packed: */
|
| - png_read_row(png_ptr, inrow, NULL);
|
| -
|
| - /* Now do the composition on each pixel in this row. */
|
| - outrow += startx;
|
| - for (; outrow < end_row; outrow += stepx)
|
| - {
|
| - png_byte alpha = inrow[1];
|
| -
|
| - if (alpha > 0) /* else use background */
|
| - {
|
| - png_uint_32 component = inrow[0];
|
| -
|
| - if (alpha < 255) /* else just use component */
|
| - {
|
| - component = png_sRGB_table[component] * alpha;
|
| - component += background * (255-alpha);
|
| - component = PNG_sRGB_FROM_LINEAR(component);
|
| - }
|
| -
|
| - outrow[0] = (png_byte)component;
|
| - }
|
| -
|
| - else
|
| - outrow[0] = background8;
|
| -
|
| - inrow += 2; /* gray and alpha channel */
|
| - }
|
| -
|
| - row += display->row_bytes;
|
| - }
|
| - }
|
| - }
|
| - }
|
| - break;
|
| -
|
| - case 16:
|
| - /* 16-bit linear with pre-multiplied alpha; the pre-multiplication must
|
| - * still be done and, maybe, the alpha channel removed. This code also
|
| - * handles the alpha-first option.
|
| - */
|
| - {
|
| - png_uint_16p first_row = png_voidcast(png_uint_16p,
|
| - display->first_row);
|
| - /* The division by two is safe because the caller passed in a
|
| - * stride which was multiplied by 2 (below) to get row_bytes.
|
| - */
|
| - ptrdiff_t step_row = display->row_bytes / 2;
|
| - int preserve_alpha = (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
|
| - unsigned int outchannels = 1+preserve_alpha;
|
| - int swap_alpha = 0;
|
| -
|
| - if (preserve_alpha && (image->format & PNG_FORMAT_FLAG_AFIRST))
|
| - swap_alpha = 1;
|
| -
|
| - for (pass = 0; pass < passes; ++pass)
|
| - {
|
| - unsigned int startx, stepx, stepy;
|
| - png_uint_32 y;
|
| -
|
| - /* The 'x' start and step are adjusted to output components here.
|
| - */
|
| - if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
| - {
|
| - /* The row may be empty for a short image: */
|
| - if (PNG_PASS_COLS(width, pass) == 0)
|
| - continue;
|
| -
|
| - startx = PNG_PASS_START_COL(pass) * outchannels;
|
| - stepx = PNG_PASS_COL_OFFSET(pass) * outchannels;
|
| - y = PNG_PASS_START_ROW(pass);
|
| - stepy = PNG_PASS_ROW_OFFSET(pass);
|
| - }
|
| -
|
| - else
|
| - {
|
| - y = 0;
|
| - startx = 0;
|
| - stepx = outchannels;
|
| - stepy = 1;
|
| - }
|
| -
|
| - for (; y<height; y += stepy)
|
| - {
|
| - png_const_uint_16p inrow;
|
| - png_uint_16p outrow = first_row + y*step_row;
|
| - png_uint_16p end_row = outrow + width * outchannels;
|
| -
|
| - /* Read the row, which is packed: */
|
| - png_read_row(png_ptr, png_voidcast(png_bytep,
|
| - display->local_row), NULL);
|
| - inrow = png_voidcast(png_const_uint_16p, display->local_row);
|
| -
|
| - /* Now do the pre-multiplication on each pixel in this row.
|
| - */
|
| - outrow += startx;
|
| - for (; outrow < end_row; outrow += stepx)
|
| - {
|
| - png_uint_32 component = inrow[0];
|
| - png_uint_16 alpha = inrow[1];
|
| -
|
| - if (alpha > 0) /* else 0 */
|
| - {
|
| - if (alpha < 65535) /* else just use component */
|
| - {
|
| - component *= alpha;
|
| - component += 32767;
|
| - component /= 65535;
|
| - }
|
| - }
|
| -
|
| - else
|
| - component = 0;
|
| -
|
| - outrow[swap_alpha] = (png_uint_16)component;
|
| - if (preserve_alpha)
|
| - outrow[1 ^ swap_alpha] = alpha;
|
| -
|
| - inrow += 2; /* components and alpha channel */
|
| - }
|
| - }
|
| - }
|
| - }
|
| - break;
|
| - }
|
| -
|
| - return 1;
|
| -}
|
| -
|
| -/* The guts of png_image_finish_read as a png_safe_execute callback. */
|
| -static int
|
| -png_image_read_direct(png_voidp argument)
|
| -{
|
| - png_image_read_control *display = png_voidcast(png_image_read_control*,
|
| - argument);
|
| - png_imagep image = display->image;
|
| - png_structrp png_ptr = image->opaque->png_ptr;
|
| - png_inforp info_ptr = image->opaque->info_ptr;
|
| -
|
| - png_uint_32 format = image->format;
|
| - int linear = (format & PNG_FORMAT_FLAG_LINEAR) != 0;
|
| - int do_local_compose = 0;
|
| - int do_local_background = 0; /* to avoid double gamma correction bug */
|
| - int passes = 0;
|
| -
|
| - /* Add transforms to ensure the correct output format is produced then check
|
| - * that the required implementation support is there. Always expand; always
|
| - * need 8 bits minimum, no palette and expanded tRNS.
|
| - */
|
| - png_set_expand(png_ptr);
|
| -
|
| - /* Now check the format to see if it was modified. */
|
| - {
|
| - png_uint_32 base_format = png_image_format(png_ptr) &
|
| - ~PNG_FORMAT_FLAG_COLORMAP /* removed by png_set_expand */;
|
| - png_uint_32 change = format ^ base_format;
|
| - png_fixed_point output_gamma;
|
| - int mode; /* alpha mode */
|
| -
|
| - /* Do this first so that we have a record if rgb to gray is happening. */
|
| - if (change & PNG_FORMAT_FLAG_COLOR)
|
| - {
|
| - /* gray<->color transformation required. */
|
| - if (format & PNG_FORMAT_FLAG_COLOR)
|
| - png_set_gray_to_rgb(png_ptr);
|
| -
|
| - else
|
| - {
|
| - /* libpng can't do both rgb to gray and
|
| - * background/pre-multiplication if there is also significant gamma
|
| - * correction, because both operations require linear colors and
|
| - * the code only supports one transform doing the gamma correction.
|
| - * Handle this by doing the pre-multiplication or background
|
| - * operation in this code, if necessary.
|
| - *
|
| - * TODO: fix this by rewriting pngrtran.c (!)
|
| - *
|
| - * For the moment (given that fixing this in pngrtran.c is an
|
| - * enormous change) 'do_local_background' is used to indicate that
|
| - * the problem exists.
|
| - */
|
| - if (base_format & PNG_FORMAT_FLAG_ALPHA)
|
| - do_local_background = 1/*maybe*/;
|
| -
|
| - png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE,
|
| - PNG_RGB_TO_GRAY_DEFAULT, PNG_RGB_TO_GRAY_DEFAULT);
|
| - }
|
| -
|
| - change &= ~PNG_FORMAT_FLAG_COLOR;
|
| - }
|
| -
|
| - /* Set the gamma appropriately, linear for 16-bit input, sRGB otherwise.
|
| - */
|
| - {
|
| - png_fixed_point input_gamma_default;
|
| -
|
| - if ((base_format & PNG_FORMAT_FLAG_LINEAR) &&
|
| - (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
|
| - input_gamma_default = PNG_GAMMA_LINEAR;
|
| - else
|
| - input_gamma_default = PNG_DEFAULT_sRGB;
|
| -
|
| - /* Call png_set_alpha_mode to set the default for the input gamma; the
|
| - * output gamma is set by a second call below.
|
| - */
|
| - png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, input_gamma_default);
|
| - }
|
| -
|
| - if (linear)
|
| - {
|
| - /* If there *is* an alpha channel in the input it must be multiplied
|
| - * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG.
|
| - */
|
| - if (base_format & PNG_FORMAT_FLAG_ALPHA)
|
| - mode = PNG_ALPHA_STANDARD; /* associated alpha */
|
| -
|
| - else
|
| - mode = PNG_ALPHA_PNG;
|
| -
|
| - output_gamma = PNG_GAMMA_LINEAR;
|
| - }
|
| -
|
| - else
|
| - {
|
| - mode = PNG_ALPHA_PNG;
|
| - output_gamma = PNG_DEFAULT_sRGB;
|
| - }
|
| -
|
| - /* If 'do_local_background' is set check for the presence of gamma
|
| - * correction; this is part of the work-round for the libpng bug
|
| - * described above.
|
| - *
|
| - * TODO: fix libpng and remove this.
|
| - */
|
| - if (do_local_background)
|
| - {
|
| - png_fixed_point gtest;
|
| -
|
| - /* This is 'png_gamma_threshold' from pngrtran.c; the test used for
|
| - * gamma correction, the screen gamma hasn't been set on png_struct
|
| - * yet; it's set below. png_struct::gamma, however, is set to the
|
| - * final value.
|
| - */
|
| - if (png_muldiv(>est, output_gamma, png_ptr->colorspace.gamma,
|
| - PNG_FP_1) && !png_gamma_significant(gtest))
|
| - do_local_background = 0;
|
| -
|
| - else if (mode == PNG_ALPHA_STANDARD)
|
| - {
|
| - do_local_background = 2/*required*/;
|
| - mode = PNG_ALPHA_PNG; /* prevent libpng doing it */
|
| - }
|
| -
|
| - /* else leave as 1 for the checks below */
|
| - }
|
| -
|
| - /* If the bit-depth changes then handle that here. */
|
| - if (change & PNG_FORMAT_FLAG_LINEAR)
|
| - {
|
| - if (linear /*16-bit output*/)
|
| - png_set_expand_16(png_ptr);
|
| -
|
| - else /* 8-bit output */
|
| - png_set_scale_16(png_ptr);
|
| -
|
| - change &= ~PNG_FORMAT_FLAG_LINEAR;
|
| - }
|
| -
|
| - /* Now the background/alpha channel changes. */
|
| - if (change & PNG_FORMAT_FLAG_ALPHA)
|
| - {
|
| - /* Removing an alpha channel requires composition for the 8-bit
|
| - * formats; for the 16-bit it is already done, above, by the
|
| - * pre-multiplication and the channel just needs to be stripped.
|
| - */
|
| - if (base_format & PNG_FORMAT_FLAG_ALPHA)
|
| - {
|
| - /* If RGB->gray is happening the alpha channel must be left and the
|
| - * operation completed locally.
|
| - *
|
| - * TODO: fix libpng and remove this.
|
| - */
|
| - if (do_local_background)
|
| - do_local_background = 2/*required*/;
|
| -
|
| - /* 16-bit output: just remove the channel */
|
| - else if (linear) /* compose on black (well, pre-multiply) */
|
| - png_set_strip_alpha(png_ptr);
|
| -
|
| - /* 8-bit output: do an appropriate compose */
|
| - else if (display->background != NULL)
|
| - {
|
| - png_color_16 c;
|
| -
|
| - c.index = 0; /*unused*/
|
| - c.red = display->background->red;
|
| - c.green = display->background->green;
|
| - c.blue = display->background->blue;
|
| - c.gray = display->background->green;
|
| -
|
| - /* This is always an 8-bit sRGB value, using the 'green' channel
|
| - * for gray is much better than calculating the luminance here;
|
| - * we can get off-by-one errors in that calculation relative to
|
| - * the app expectations and that will show up in transparent
|
| - * pixels.
|
| - */
|
| - png_set_background_fixed(png_ptr, &c,
|
| - PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
| - 0/*gamma: not used*/);
|
| - }
|
| -
|
| - else /* compose on row: implemented below. */
|
| - {
|
| - do_local_compose = 1;
|
| - /* This leaves the alpha channel in the output, so it has to be
|
| - * removed by the code below. Set the encoding to the 'OPTIMIZE'
|
| - * one so the code only has to hack on the pixels that require
|
| - * composition.
|
| - */
|
| - mode = PNG_ALPHA_OPTIMIZED;
|
| - }
|
| - }
|
| -
|
| - else /* output needs an alpha channel */
|
| - {
|
| - /* This is tricky because it happens before the swap operation has
|
| - * been accomplished; however, the swap does *not* swap the added
|
| - * alpha channel (weird API), so it must be added in the correct
|
| - * place.
|
| - */
|
| - png_uint_32 filler; /* opaque filler */
|
| - int where;
|
| -
|
| - if (linear)
|
| - filler = 65535;
|
| -
|
| - else
|
| - filler = 255;
|
| -
|
| -# ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
| - if (format & PNG_FORMAT_FLAG_AFIRST)
|
| - {
|
| - where = PNG_FILLER_BEFORE;
|
| - change &= ~PNG_FORMAT_FLAG_AFIRST;
|
| - }
|
| -
|
| - else
|
| -# endif
|
| - where = PNG_FILLER_AFTER;
|
| -
|
| - png_set_add_alpha(png_ptr, filler, where);
|
| - }
|
| -
|
| - /* This stops the (irrelevant) call to swap_alpha below. */
|
| - change &= ~PNG_FORMAT_FLAG_ALPHA;
|
| - }
|
| -
|
| - /* Now set the alpha mode correctly; this is always done, even if there is
|
| - * no alpha channel in either the input or the output because it correctly
|
| - * sets the output gamma.
|
| - */
|
| - png_set_alpha_mode_fixed(png_ptr, mode, output_gamma);
|
| -
|
| -# ifdef PNG_FORMAT_BGR_SUPPORTED
|
| - if (change & PNG_FORMAT_FLAG_BGR)
|
| - {
|
| - /* Check only the output format; PNG is never BGR; don't do this if
|
| - * the output is gray, but fix up the 'format' value in that case.
|
| - */
|
| - if (format & PNG_FORMAT_FLAG_COLOR)
|
| - png_set_bgr(png_ptr);
|
| -
|
| - else
|
| - format &= ~PNG_FORMAT_FLAG_BGR;
|
| -
|
| - change &= ~PNG_FORMAT_FLAG_BGR;
|
| - }
|
| -# endif
|
| -
|
| -# ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
| - if (change & PNG_FORMAT_FLAG_AFIRST)
|
| - {
|
| - /* Only relevant if there is an alpha channel - it's particularly
|
| - * important to handle this correctly because do_local_compose may
|
| - * be set above and then libpng will keep the alpha channel for this
|
| - * code to remove.
|
| - */
|
| - if (format & PNG_FORMAT_FLAG_ALPHA)
|
| - {
|
| - /* Disable this if doing a local background,
|
| - * TODO: remove this when local background is no longer required.
|
| - */
|
| - if (do_local_background != 2)
|
| - png_set_swap_alpha(png_ptr);
|
| - }
|
| -
|
| - else
|
| - format &= ~PNG_FORMAT_FLAG_AFIRST;
|
| -
|
| - change &= ~PNG_FORMAT_FLAG_AFIRST;
|
| - }
|
| -# endif
|
| -
|
| - /* If the *output* is 16-bit then we need to check for a byte-swap on this
|
| - * architecture.
|
| - */
|
| - if (linear)
|
| - {
|
| - PNG_CONST png_uint_16 le = 0x0001;
|
| -
|
| - if (*(png_const_bytep)&le)
|
| - png_set_swap(png_ptr);
|
| - }
|
| -
|
| - /* If change is not now 0 some transformation is missing - error out. */
|
| - if (change)
|
| - png_error(png_ptr, "png_read_image: unsupported transformation");
|
| - }
|
| -
|
| - PNG_SKIP_CHUNKS(png_ptr);
|
| -
|
| - /* Update the 'info' structure and make sure the result is as required; first
|
| - * make sure to turn on the interlace handling if it will be required
|
| - * (because it can't be turned on *after* the call to png_read_update_info!)
|
| - *
|
| - * TODO: remove the do_local_background fixup below.
|
| - */
|
| - if (!do_local_compose && do_local_background != 2)
|
| - passes = png_set_interlace_handling(png_ptr);
|
| -
|
| - png_read_update_info(png_ptr, info_ptr);
|
| -
|
| - {
|
| - png_uint_32 info_format = 0;
|
| -
|
| - if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
|
| - info_format |= PNG_FORMAT_FLAG_COLOR;
|
| -
|
| - if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
|
| - {
|
| - /* do_local_compose removes this channel below. */
|
| - if (!do_local_compose)
|
| - {
|
| - /* do_local_background does the same if required. */
|
| - if (do_local_background != 2 ||
|
| - (format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| - info_format |= PNG_FORMAT_FLAG_ALPHA;
|
| - }
|
| - }
|
| -
|
| - else if (do_local_compose) /* internal error */
|
| - png_error(png_ptr, "png_image_read: alpha channel lost");
|
| -
|
| - if (info_ptr->bit_depth == 16)
|
| - info_format |= PNG_FORMAT_FLAG_LINEAR;
|
| -
|
| -# ifdef PNG_FORMAT_BGR_SUPPORTED
|
| - if (png_ptr->transformations & PNG_BGR)
|
| - info_format |= PNG_FORMAT_FLAG_BGR;
|
| -# endif
|
| -
|
| -# ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
| - if (do_local_background == 2)
|
| - {
|
| - if (format & PNG_FORMAT_FLAG_AFIRST)
|
| - info_format |= PNG_FORMAT_FLAG_AFIRST;
|
| - }
|
| -
|
| - if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0 ||
|
| - ((png_ptr->transformations & PNG_ADD_ALPHA) != 0 &&
|
| - (png_ptr->flags & PNG_FLAG_FILLER_AFTER) == 0))
|
| - {
|
| - if (do_local_background == 2)
|
| - png_error(png_ptr, "unexpected alpha swap transformation");
|
| -
|
| - info_format |= PNG_FORMAT_FLAG_AFIRST;
|
| - }
|
| -# endif
|
| -
|
| - /* This is actually an internal error. */
|
| - if (info_format != format)
|
| - png_error(png_ptr, "png_read_image: invalid transformations");
|
| - }
|
| -
|
| - /* Now read the rows. If do_local_compose is set then it is necessary to use
|
| - * a local row buffer. The output will be GA, RGBA or BGRA and must be
|
| - * converted to G, RGB or BGR as appropriate. The 'local_row' member of the
|
| - * display acts as a flag.
|
| - */
|
| - {
|
| - png_voidp first_row = display->buffer;
|
| - ptrdiff_t row_bytes = display->row_stride;
|
| -
|
| - if (linear)
|
| - row_bytes *= 2;
|
| -
|
| - /* The following expression is designed to work correctly whether it gives
|
| - * a signed or an unsigned result.
|
| - */
|
| - if (row_bytes < 0)
|
| - {
|
| - char *ptr = png_voidcast(char*, first_row);
|
| - ptr += (image->height-1) * (-row_bytes);
|
| - first_row = png_voidcast(png_voidp, ptr);
|
| - }
|
| -
|
| - display->first_row = first_row;
|
| - display->row_bytes = row_bytes;
|
| - }
|
| -
|
| - if (do_local_compose)
|
| - {
|
| - int result;
|
| - png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
| -
|
| - display->local_row = row;
|
| - result = png_safe_execute(image, png_image_read_composite, display);
|
| - display->local_row = NULL;
|
| - png_free(png_ptr, row);
|
| -
|
| - return result;
|
| - }
|
| -
|
| - else if (do_local_background == 2)
|
| - {
|
| - int result;
|
| - png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
| -
|
| - display->local_row = row;
|
| - result = png_safe_execute(image, png_image_read_background, display);
|
| - display->local_row = NULL;
|
| - png_free(png_ptr, row);
|
| -
|
| - return result;
|
| - }
|
| -
|
| - else
|
| - {
|
| - png_alloc_size_t row_bytes = display->row_bytes;
|
| -
|
| - while (--passes >= 0)
|
| - {
|
| - png_uint_32 y = image->height;
|
| - png_bytep row = png_voidcast(png_bytep, display->first_row);
|
| -
|
| - while (y-- > 0)
|
| - {
|
| - png_read_row(png_ptr, row, NULL);
|
| - row += row_bytes;
|
| - }
|
| - }
|
| -
|
| - return 1;
|
| - }
|
| -}
|
| -
|
| -int PNGAPI
|
| -png_image_finish_read(png_imagep image, png_const_colorp background,
|
| - void *buffer, png_int_32 row_stride, void *colormap)
|
| -{
|
| - if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
| - {
|
| - png_uint_32 check;
|
| -
|
| - if (row_stride == 0)
|
| - row_stride = PNG_IMAGE_ROW_STRIDE(*image);
|
| -
|
| - if (row_stride < 0)
|
| - check = -row_stride;
|
| -
|
| - else
|
| - check = row_stride;
|
| -
|
| - if (image->opaque != NULL && buffer != NULL &&
|
| - check >= PNG_IMAGE_ROW_STRIDE(*image))
|
| - {
|
| - if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 ||
|
| - (image->colormap_entries > 0 && colormap != NULL))
|
| - {
|
| - int result;
|
| - png_image_read_control display;
|
| -
|
| - memset(&display, 0, (sizeof display));
|
| - display.image = image;
|
| - display.buffer = buffer;
|
| - display.row_stride = row_stride;
|
| - display.colormap = colormap;
|
| - display.background = background;
|
| - display.local_row = NULL;
|
| -
|
| - /* Choose the correct 'end' routine; for the color-map case all the
|
| - * setup has already been done.
|
| - */
|
| - if (image->format & PNG_FORMAT_FLAG_COLORMAP)
|
| - result =
|
| - png_safe_execute(image, png_image_read_colormap, &display) &&
|
| - png_safe_execute(image, png_image_read_colormapped, &display);
|
| -
|
| - else
|
| - result =
|
| - png_safe_execute(image, png_image_read_direct, &display);
|
| -
|
| - png_image_free(image);
|
| - return result;
|
| - }
|
| -
|
| - else
|
| - return png_image_error(image,
|
| - "png_image_finish_read[color-map]: no color-map");
|
| - }
|
| -
|
| - else
|
| - return png_image_error(image,
|
| - "png_image_finish_read: invalid argument");
|
| - }
|
| -
|
| - else if (image != NULL)
|
| - return png_image_error(image,
|
| - "png_image_finish_read: damaged PNG_IMAGE_VERSION");
|
| -
|
| - return 0;
|
| -}
|
| -
|
| -#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */
|
| -#endif /* PNG_READ_SUPPORTED */
|
| +
|
| +/* pngread.c - read a PNG file
|
| + *
|
| + * Last changed in libpng 1.6.17 [March 26, 2015]
|
| + * Copyright (c) 1998-2015 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
|
| + *
|
| + * This file contains routines that an application calls directly to
|
| + * read a PNG file or stream.
|
| + */
|
| +
|
| +#include "pngpriv.h"
|
| +#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
|
| +# include <errno.h>
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_SUPPORTED
|
| +
|
| +/* Create a PNG structure for reading, and allocate any memory needed. */
|
| +PNG_FUNCTION(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),PNG_ALLOCATED)
|
| +{
|
| +#ifndef PNG_USER_MEM_SUPPORTED
|
| + png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
|
| + error_fn, warn_fn, NULL, NULL, NULL);
|
| +#else
|
| + 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_FUNCTION(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),PNG_ALLOCATED)
|
| +{
|
| + png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
|
| + error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
|
| +#endif /* USER_MEM */
|
| +
|
| + if (png_ptr != NULL)
|
| + {
|
| + png_ptr->mode = PNG_IS_READ_STRUCT;
|
| +
|
| + /* Added in libpng-1.6.0; this can be used to detect a read structure if
|
| + * required (it will be zero in a write structure.)
|
| + */
|
| +# ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| + png_ptr->IDAT_read_size = PNG_IDAT_READ_SIZE;
|
| +# endif
|
| +
|
| +# ifdef PNG_BENIGN_READ_ERRORS_SUPPORTED
|
| + png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
|
| +
|
| + /* In stable builds only warn if an application error can be completely
|
| + * handled.
|
| + */
|
| +# if PNG_RELEASE_BUILD
|
| + png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
|
| +# endif
|
| +# endif
|
| +
|
| + /* TODO: delay this, it can be done in png_init_io (if the app doesn't
|
| + * do it itself) avoiding setting the default function if it is not
|
| + * required.
|
| + */
|
| + png_set_read_fn(png_ptr, NULL, NULL);
|
| + }
|
| +
|
| + return png_ptr;
|
| +}
|
| +
|
| +
|
| +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| +/* 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_structrp png_ptr, png_inforp info_ptr)
|
| +{
|
| +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| + int keep;
|
| +#endif
|
| +
|
| + png_debug(1, "in png_read_info");
|
| +
|
| + if (png_ptr == NULL || info_ptr == NULL)
|
| + return;
|
| +
|
| + /* Read and check the PNG file signature. */
|
| + png_read_sig(png_ptr, info_ptr);
|
| +
|
| + for (;;)
|
| + {
|
| + png_uint_32 length = png_read_chunk_header(png_ptr);
|
| + png_uint_32 chunk_name = png_ptr->chunk_name;
|
| +
|
| + /* IDAT logic needs to happen here to simplify getting the two flags
|
| + * right.
|
| + */
|
| + if (chunk_name == png_IDAT)
|
| + {
|
| + if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
|
| + png_chunk_error(png_ptr, "Missing IHDR before IDAT");
|
| +
|
| + else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
|
| + (png_ptr->mode & PNG_HAVE_PLTE) == 0)
|
| + png_chunk_error(png_ptr, "Missing PLTE before IDAT");
|
| +
|
| + else if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
|
| + png_chunk_benign_error(png_ptr, "Too many IDATs found");
|
| +
|
| + png_ptr->mode |= PNG_HAVE_IDAT;
|
| + }
|
| +
|
| + else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
|
| + png_ptr->mode |= PNG_AFTER_IDAT;
|
| +
|
| + /* This should be a binary subdivision search or a hash for
|
| + * matching the chunk name rather than a linear search.
|
| + */
|
| + if (chunk_name == png_IHDR)
|
| + png_handle_IHDR(png_ptr, info_ptr, length);
|
| +
|
| + else if (chunk_name == png_IEND)
|
| + png_handle_IEND(png_ptr, info_ptr, length);
|
| +
|
| +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| + else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
|
| + {
|
| + png_handle_unknown(png_ptr, info_ptr, length, keep);
|
| +
|
| + if (chunk_name == png_PLTE)
|
| + png_ptr->mode |= PNG_HAVE_PLTE;
|
| +
|
| + else if (chunk_name == png_IDAT)
|
| + {
|
| + png_ptr->idat_size = 0; /* It has been consumed */
|
| + break;
|
| + }
|
| + }
|
| +#endif
|
| + else if (chunk_name == png_PLTE)
|
| + png_handle_PLTE(png_ptr, info_ptr, length);
|
| +
|
| + else if (chunk_name == png_IDAT)
|
| + {
|
| + png_ptr->idat_size = length;
|
| + break;
|
| + }
|
| +
|
| +#ifdef PNG_READ_bKGD_SUPPORTED
|
| + else if (chunk_name == png_bKGD)
|
| + png_handle_bKGD(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_cHRM_SUPPORTED
|
| + else if (chunk_name == png_cHRM)
|
| + png_handle_cHRM(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_gAMA_SUPPORTED
|
| + else if (chunk_name == png_gAMA)
|
| + png_handle_gAMA(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_hIST_SUPPORTED
|
| + else if (chunk_name == png_hIST)
|
| + png_handle_hIST(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_oFFs_SUPPORTED
|
| + else if (chunk_name == png_oFFs)
|
| + png_handle_oFFs(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_pCAL_SUPPORTED
|
| + else if (chunk_name == png_pCAL)
|
| + png_handle_pCAL(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_sCAL_SUPPORTED
|
| + else if (chunk_name == png_sCAL)
|
| + png_handle_sCAL(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_pHYs_SUPPORTED
|
| + else if (chunk_name == png_pHYs)
|
| + png_handle_pHYs(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_sBIT_SUPPORTED
|
| + else if (chunk_name == png_sBIT)
|
| + png_handle_sBIT(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_sRGB_SUPPORTED
|
| + else if (chunk_name == png_sRGB)
|
| + png_handle_sRGB(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_iCCP_SUPPORTED
|
| + else if (chunk_name == png_iCCP)
|
| + png_handle_iCCP(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_sPLT_SUPPORTED
|
| + else if (chunk_name == png_sPLT)
|
| + png_handle_sPLT(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_tEXt_SUPPORTED
|
| + else if (chunk_name == png_tEXt)
|
| + png_handle_tEXt(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_tIME_SUPPORTED
|
| + else if (chunk_name == png_tIME)
|
| + png_handle_tIME(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_tRNS_SUPPORTED
|
| + else if (chunk_name == png_tRNS)
|
| + png_handle_tRNS(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_zTXt_SUPPORTED
|
| + else if (chunk_name == png_zTXt)
|
| + png_handle_zTXt(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_iTXt_SUPPORTED
|
| + else if (chunk_name == png_iTXt)
|
| + png_handle_iTXt(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| + else
|
| + png_handle_unknown(png_ptr, info_ptr, length,
|
| + PNG_HANDLE_CHUNK_AS_DEFAULT);
|
| + }
|
| +}
|
| +#endif /* SEQUENTIAL_READ */
|
| +
|
| +/* Optional call to update the users info_ptr structure */
|
| +void PNGAPI
|
| +png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
|
| +{
|
| + png_debug(1, "in png_read_update_info");
|
| +
|
| + if (png_ptr != NULL)
|
| + {
|
| + if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
|
| + {
|
| + png_read_start_row(png_ptr);
|
| +
|
| +# ifdef PNG_READ_TRANSFORMS_SUPPORTED
|
| + png_read_transform_info(png_ptr, info_ptr);
|
| +# else
|
| + PNG_UNUSED(info_ptr)
|
| +# endif
|
| + }
|
| +
|
| + /* New in 1.6.0 this avoids the bug of doing the initializations twice */
|
| + else
|
| + png_app_error(png_ptr,
|
| + "png_read_update_info/png_start_read_image: duplicate call");
|
| + }
|
| +}
|
| +
|
| +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| +/* 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_structrp png_ptr)
|
| +{
|
| + png_debug(1, "in png_start_read_image");
|
| +
|
| + if (png_ptr != NULL)
|
| + {
|
| + if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
|
| + png_read_start_row(png_ptr);
|
| +
|
| + /* New in 1.6.0 this avoids the bug of doing the initializations twice */
|
| + else
|
| + png_app_error(png_ptr,
|
| + "png_start_read_image/png_read_update_info: duplicate call");
|
| + }
|
| +}
|
| +#endif /* SEQUENTIAL_READ */
|
| +
|
| +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| +#ifdef PNG_MNG_FEATURES_SUPPORTED
|
| +/* Undoes intrapixel differencing,
|
| + * NOTE: this is apparently only supported in the 'sequential' reader.
|
| + */
|
| +static void
|
| +png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
|
| +{
|
| + png_debug(1, "in png_do_read_intrapixel");
|
| +
|
| + if (
|
| + (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
|
| + {
|
| + int bytes_per_pixel;
|
| + png_uint_32 row_width = row_info->width;
|
| +
|
| + if (row_info->bit_depth == 8)
|
| + {
|
| + png_bytep rp;
|
| + png_uint_32 i;
|
| +
|
| + if (row_info->color_type == PNG_COLOR_TYPE_RGB)
|
| + bytes_per_pixel = 3;
|
| +
|
| + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
|
| + bytes_per_pixel = 4;
|
| +
|
| + else
|
| + return;
|
| +
|
| + for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
|
| + {
|
| + *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
|
| + *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
|
| + }
|
| + }
|
| + else if (row_info->bit_depth == 16)
|
| + {
|
| + png_bytep rp;
|
| + png_uint_32 i;
|
| +
|
| + if (row_info->color_type == PNG_COLOR_TYPE_RGB)
|
| + bytes_per_pixel = 6;
|
| +
|
| + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
|
| + bytes_per_pixel = 8;
|
| +
|
| + else
|
| + return;
|
| +
|
| + for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
|
| + {
|
| + png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
|
| + png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
|
| + png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
|
| + png_uint_32 red = (s0 + s1 + 65536) & 0xffff;
|
| + png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
|
| + *(rp ) = (png_byte)((red >> 8) & 0xff);
|
| + *(rp + 1) = (png_byte)(red & 0xff);
|
| + *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
|
| + *(rp + 5) = (png_byte)(blue & 0xff);
|
| + }
|
| + }
|
| + }
|
| +}
|
| +#endif /* MNG_FEATURES */
|
| +
|
| +void PNGAPI
|
| +png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
|
| +{
|
| + png_row_info row_info;
|
| +
|
| + if (png_ptr == NULL)
|
| + return;
|
| +
|
| + png_debug2(1, "in png_read_row (row %lu, pass %d)",
|
| + (unsigned long)png_ptr->row_number, png_ptr->pass);
|
| +
|
| + /* png_read_start_row sets the information (in particular iwidth) for this
|
| + * interlace pass.
|
| + */
|
| + if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
|
| + png_read_start_row(png_ptr);
|
| +
|
| + /* 1.5.6: row_info moved out of png_struct to a local here. */
|
| + row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
|
| + row_info.color_type = png_ptr->color_type;
|
| + row_info.bit_depth = png_ptr->bit_depth;
|
| + row_info.channels = png_ptr->channels;
|
| + row_info.pixel_depth = png_ptr->pixel_depth;
|
| + row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
|
| +
|
| +#ifdef PNG_WARNINGS_SUPPORTED
|
| + 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) != 0)
|
| + 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) != 0)
|
| + 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) != 0)
|
| + 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) != 0)
|
| + 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) != 0)
|
| + 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) != 0)
|
| + 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) != 0)
|
| + png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
|
| +#endif
|
| + }
|
| +#endif /* WARNINGS */
|
| +
|
| +#ifdef PNG_READ_INTERLACING_SUPPORTED
|
| + /* If interlaced and we do not need a new row, combine row and return.
|
| + * Notice that the pixels we have from previous rows have been transformed
|
| + * already; we can only combine like with like (transformed or
|
| + * untransformed) and, because of the libpng API for interlaced images, this
|
| + * means we must transform before de-interlacing.
|
| + */
|
| + if (png_ptr->interlaced != 0 &&
|
| + (png_ptr->transformations & PNG_INTERLACE) != 0)
|
| + {
|
| + switch (png_ptr->pass)
|
| + {
|
| + case 0:
|
| + if (png_ptr->row_number & 0x07)
|
| + {
|
| + if (dsp_row != NULL)
|
| + png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
| + 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, 1/*display*/);
|
| +
|
| + 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, 1/*display*/);
|
| +
|
| + 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, 1/*display*/);
|
| +
|
| + 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, 1/*display*/);
|
| +
|
| + 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, 1/*display*/);
|
| +
|
| + png_read_finish_row(png_ptr);
|
| + return;
|
| + }
|
| + break;
|
| +
|
| + default:
|
| + case 6:
|
| + if ((png_ptr->row_number & 1) == 0)
|
| + {
|
| + png_read_finish_row(png_ptr);
|
| + return;
|
| + }
|
| + break;
|
| + }
|
| + }
|
| +#endif
|
| +
|
| + if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
|
| + png_error(png_ptr, "Invalid attempt to read row data");
|
| +
|
| + /* Fill the row with IDAT data: */
|
| + png_read_IDAT_data(png_ptr, png_ptr->row_buf, row_info.rowbytes + 1);
|
| +
|
| + if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
|
| + {
|
| + if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
|
| + png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
|
| + png_ptr->prev_row + 1, png_ptr->row_buf[0]);
|
| + else
|
| + png_error(png_ptr, "bad adaptive filter value");
|
| + }
|
| +
|
| + /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
|
| + * 1.5.6, while the buffer really is this big in current versions of libpng
|
| + * it may not be in the future, so this was changed just to copy the
|
| + * interlaced count:
|
| + */
|
| + memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
|
| +
|
| +#ifdef PNG_MNG_FEATURES_SUPPORTED
|
| + if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
|
| + (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
|
| + {
|
| + /* Intrapixel differencing */
|
| + png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
|
| + }
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_TRANSFORMS_SUPPORTED
|
| + if (png_ptr->transformations)
|
| + png_do_read_transformations(png_ptr, &row_info);
|
| +#endif
|
| +
|
| + /* The transformed pixel depth should match the depth now in row_info. */
|
| + if (png_ptr->transformed_pixel_depth == 0)
|
| + {
|
| + png_ptr->transformed_pixel_depth = row_info.pixel_depth;
|
| + if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
|
| + png_error(png_ptr, "sequential row overflow");
|
| + }
|
| +
|
| + else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
|
| + png_error(png_ptr, "internal sequential row size calculation error");
|
| +
|
| +#ifdef PNG_READ_INTERLACING_SUPPORTED
|
| + /* Expand interlaced rows to full size */
|
| + if (png_ptr->interlaced != 0 &&
|
| + (png_ptr->transformations & PNG_INTERLACE) != 0)
|
| + {
|
| + if (png_ptr->pass < 6)
|
| + png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
|
| + png_ptr->transformations);
|
| +
|
| + if (dsp_row != NULL)
|
| + png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
| +
|
| + if (row != NULL)
|
| + png_combine_row(png_ptr, row, 0/*row*/);
|
| + }
|
| +
|
| + else
|
| +#endif
|
| + {
|
| + if (row != NULL)
|
| + png_combine_row(png_ptr, row, -1/*ignored*/);
|
| +
|
| + if (dsp_row != NULL)
|
| + png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
|
| + }
|
| + 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);
|
| +
|
| +}
|
| +#endif /* SEQUENTIAL_READ */
|
| +
|
| +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| +/* 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 this version of libpng
|
| + */
|
| +
|
| +void PNGAPI
|
| +png_read_rows(png_structrp 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");
|
| +
|
| + if (png_ptr == NULL)
|
| + return;
|
| +
|
| + 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++;
|
| + }
|
| +}
|
| +#endif /* SEQUENTIAL_READ */
|
| +
|
| +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| +/* 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 this version of libpng
|
| + */
|
| +void PNGAPI
|
| +png_read_image(png_structrp png_ptr, png_bytepp image)
|
| +{
|
| + png_uint_32 i, image_height;
|
| + int pass, j;
|
| + png_bytepp rp;
|
| +
|
| + png_debug(1, "in png_read_image");
|
| +
|
| + if (png_ptr == NULL)
|
| + return;
|
| +
|
| +#ifdef PNG_READ_INTERLACING_SUPPORTED
|
| + if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
|
| + {
|
| + pass = png_set_interlace_handling(png_ptr);
|
| + /* And make sure transforms are initialized. */
|
| + png_start_read_image(png_ptr);
|
| + }
|
| + else
|
| + {
|
| + if (png_ptr->interlaced != 0 &&
|
| + (png_ptr->transformations & PNG_INTERLACE) == 0)
|
| + {
|
| + /* Caller called png_start_read_image or png_read_update_info without
|
| + * first turning on the PNG_INTERLACE transform. We can fix this here,
|
| + * but the caller should do it!
|
| + */
|
| + png_warning(png_ptr, "Interlace handling should be turned on when "
|
| + "using png_read_image");
|
| + /* Make sure this is set correctly */
|
| + png_ptr->num_rows = png_ptr->height;
|
| + }
|
| +
|
| + /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
|
| + * the above error case.
|
| + */
|
| + 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;
|
| +
|
| + for (j = 0; j < pass; j++)
|
| + {
|
| + rp = image;
|
| + for (i = 0; i < image_height; i++)
|
| + {
|
| + png_read_row(png_ptr, *rp, NULL);
|
| + rp++;
|
| + }
|
| + }
|
| +}
|
| +#endif /* SEQUENTIAL_READ */
|
| +
|
| +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| +/* 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_structrp png_ptr, png_inforp info_ptr)
|
| +{
|
| +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| + int keep;
|
| +#endif
|
| +
|
| + png_debug(1, "in png_read_end");
|
| +
|
| + if (png_ptr == NULL)
|
| + return;
|
| +
|
| + /* If png_read_end is called in the middle of reading the rows there may
|
| + * still be pending IDAT data and an owned zstream. Deal with this here.
|
| + */
|
| +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| + if (png_chunk_unknown_handling(png_ptr, png_IDAT) == 0)
|
| +#endif
|
| + png_read_finish_IDAT(png_ptr);
|
| +
|
| +#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
|
| + /* Report invalid palette index; added at libng-1.5.10 */
|
| + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
|
| + png_ptr->num_palette_max > png_ptr->num_palette)
|
| + png_benign_error(png_ptr, "Read palette index exceeding num_palette");
|
| +#endif
|
| +
|
| + do
|
| + {
|
| + png_uint_32 length = png_read_chunk_header(png_ptr);
|
| + png_uint_32 chunk_name = png_ptr->chunk_name;
|
| +
|
| + if (chunk_name == png_IEND)
|
| + png_handle_IEND(png_ptr, info_ptr, length);
|
| +
|
| + else if (chunk_name == png_IHDR)
|
| + png_handle_IHDR(png_ptr, info_ptr, length);
|
| +
|
| + else if (info_ptr == NULL)
|
| + png_crc_finish(png_ptr, length);
|
| +
|
| +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| + else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
|
| + {
|
| + if (chunk_name == png_IDAT)
|
| + {
|
| + if ((length > 0) ||
|
| + (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
|
| + png_benign_error(png_ptr, "Too many IDATs found");
|
| + }
|
| + png_handle_unknown(png_ptr, info_ptr, length, keep);
|
| + if (chunk_name == png_PLTE)
|
| + png_ptr->mode |= PNG_HAVE_PLTE;
|
| + }
|
| +#endif
|
| +
|
| + else if (chunk_name == png_IDAT)
|
| + {
|
| + /* 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_HAVE_CHUNK_AFTER_IDAT) != 0)
|
| + png_benign_error(png_ptr, "Too many IDATs found");
|
| +
|
| + png_crc_finish(png_ptr, length);
|
| + }
|
| + else if (chunk_name == png_PLTE)
|
| + png_handle_PLTE(png_ptr, info_ptr, length);
|
| +
|
| +#ifdef PNG_READ_bKGD_SUPPORTED
|
| + else if (chunk_name == png_bKGD)
|
| + png_handle_bKGD(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_cHRM_SUPPORTED
|
| + else if (chunk_name == png_cHRM)
|
| + png_handle_cHRM(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_gAMA_SUPPORTED
|
| + else if (chunk_name == png_gAMA)
|
| + png_handle_gAMA(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_hIST_SUPPORTED
|
| + else if (chunk_name == png_hIST)
|
| + png_handle_hIST(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_oFFs_SUPPORTED
|
| + else if (chunk_name == png_oFFs)
|
| + png_handle_oFFs(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_pCAL_SUPPORTED
|
| + else if (chunk_name == png_pCAL)
|
| + png_handle_pCAL(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_sCAL_SUPPORTED
|
| + else if (chunk_name == png_sCAL)
|
| + png_handle_sCAL(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_pHYs_SUPPORTED
|
| + else if (chunk_name == png_pHYs)
|
| + png_handle_pHYs(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_sBIT_SUPPORTED
|
| + else if (chunk_name == png_sBIT)
|
| + png_handle_sBIT(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_sRGB_SUPPORTED
|
| + else if (chunk_name == png_sRGB)
|
| + png_handle_sRGB(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_iCCP_SUPPORTED
|
| + else if (chunk_name == png_iCCP)
|
| + png_handle_iCCP(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_sPLT_SUPPORTED
|
| + else if (chunk_name == png_sPLT)
|
| + png_handle_sPLT(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_tEXt_SUPPORTED
|
| + else if (chunk_name == png_tEXt)
|
| + png_handle_tEXt(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_tIME_SUPPORTED
|
| + else if (chunk_name == png_tIME)
|
| + png_handle_tIME(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_tRNS_SUPPORTED
|
| + else if (chunk_name == png_tRNS)
|
| + png_handle_tRNS(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_zTXt_SUPPORTED
|
| + else if (chunk_name == png_zTXt)
|
| + png_handle_zTXt(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_iTXt_SUPPORTED
|
| + else if (chunk_name == png_iTXt)
|
| + png_handle_iTXt(png_ptr, info_ptr, length);
|
| +#endif
|
| +
|
| + else
|
| + png_handle_unknown(png_ptr, info_ptr, length,
|
| + PNG_HANDLE_CHUNK_AS_DEFAULT);
|
| + } while ((png_ptr->mode & PNG_HAVE_IEND) == 0);
|
| +}
|
| +#endif /* SEQUENTIAL_READ */
|
| +
|
| +/* Free all memory used in the read struct */
|
| +static void
|
| +png_read_destroy(png_structrp png_ptr)
|
| +{
|
| + png_debug(1, "in png_read_destroy");
|
| +
|
| +#ifdef PNG_READ_GAMMA_SUPPORTED
|
| + png_destroy_gamma_table(png_ptr);
|
| +#endif
|
| +
|
| + png_free(png_ptr, png_ptr->big_row_buf);
|
| + png_ptr->big_row_buf = NULL;
|
| + png_free(png_ptr, png_ptr->big_prev_row);
|
| + png_ptr->big_prev_row = NULL;
|
| + png_free(png_ptr, png_ptr->read_buffer);
|
| + png_ptr->read_buffer = NULL;
|
| +
|
| +#ifdef PNG_READ_QUANTIZE_SUPPORTED
|
| + png_free(png_ptr, png_ptr->palette_lookup);
|
| + png_ptr->palette_lookup = NULL;
|
| + png_free(png_ptr, png_ptr->quantize_index);
|
| + png_ptr->quantize_index = NULL;
|
| +#endif
|
| +
|
| + if ((png_ptr->free_me & PNG_FREE_PLTE) != 0)
|
| + {
|
| + png_zfree(png_ptr, png_ptr->palette);
|
| + png_ptr->palette = NULL;
|
| + }
|
| + png_ptr->free_me &= ~PNG_FREE_PLTE;
|
| +
|
| +#if defined(PNG_tRNS_SUPPORTED) || \
|
| + defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
|
| + if ((png_ptr->free_me & PNG_FREE_TRNS) != 0)
|
| + {
|
| + png_free(png_ptr, png_ptr->trans_alpha);
|
| + png_ptr->trans_alpha = NULL;
|
| + }
|
| + png_ptr->free_me &= ~PNG_FREE_TRNS;
|
| +#endif
|
| +
|
| + inflateEnd(&png_ptr->zstream);
|
| +
|
| +#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
|
| + png_free(png_ptr, png_ptr->save_buffer);
|
| + png_ptr->save_buffer = NULL;
|
| +#endif
|
| +
|
| +#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) && \
|
| + defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
|
| + png_free(png_ptr, png_ptr->unknown_chunk.data);
|
| + png_ptr->unknown_chunk.data = NULL;
|
| +#endif
|
| +
|
| +#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
|
| + png_free(png_ptr, png_ptr->chunk_list);
|
| + png_ptr->chunk_list = NULL;
|
| +#endif
|
| +
|
| + /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error
|
| + * callbacks are still set at this point. They are required to complete the
|
| + * destruction of the png_struct itself.
|
| + */
|
| +}
|
| +
|
| +/* 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_structrp png_ptr = NULL;
|
| +
|
| + png_debug(1, "in png_destroy_read_struct");
|
| +
|
| + if (png_ptr_ptr != NULL)
|
| + png_ptr = *png_ptr_ptr;
|
| +
|
| + if (png_ptr == NULL)
|
| + return;
|
| +
|
| + /* libpng 1.6.0: use the API to destroy info structs to ensure consistent
|
| + * behavior. Prior to 1.6.0 libpng did extra 'info' destruction in this API.
|
| + * The extra was, apparently, unnecessary yet this hides memory leak bugs.
|
| + */
|
| + png_destroy_info_struct(png_ptr, end_info_ptr_ptr);
|
| + png_destroy_info_struct(png_ptr, info_ptr_ptr);
|
| +
|
| + *png_ptr_ptr = NULL;
|
| + png_read_destroy(png_ptr);
|
| + png_destroy_png_struct(png_ptr);
|
| +}
|
| +
|
| +void PNGAPI
|
| +png_set_read_status_fn(png_structrp png_ptr, png_read_status_ptr read_row_fn)
|
| +{
|
| + if (png_ptr == NULL)
|
| + return;
|
| +
|
| + png_ptr->read_row_fn = read_row_fn;
|
| +}
|
| +
|
| +
|
| +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
| +#ifdef PNG_INFO_IMAGE_SUPPORTED
|
| +void PNGAPI
|
| +png_read_png(png_structrp png_ptr, png_inforp info_ptr,
|
| + int transforms,
|
| + voidp params)
|
| +{
|
| + if (png_ptr == NULL || info_ptr == NULL)
|
| + return;
|
| +
|
| + /* 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);
|
| + if (info_ptr->height > PNG_UINT_32_MAX/(sizeof (png_bytep)))
|
| + png_error(png_ptr, "Image is too high to process with png_read_png()");
|
| +
|
| + /* -------------- image transformations start here ------------------- */
|
| + /* libpng 1.6.10: add code to cause a png_app_error if a selected TRANSFORM
|
| + * is not implemented. This will only happen in de-configured (non-default)
|
| + * libpng builds. The results can be unexpected - png_read_png may return
|
| + * short or mal-formed rows because the transform is skipped.
|
| + */
|
| +
|
| + /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
|
| + */
|
| + if ((transforms & PNG_TRANSFORM_SCALE_16) != 0)
|
| + /* Added at libpng-1.5.4. "strip_16" produces the same result that it
|
| + * did in earlier versions, while "scale_16" is now more accurate.
|
| + */
|
| +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
|
| + png_set_scale_16(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_SCALE_16 not supported");
|
| +#endif
|
| +
|
| + /* If both SCALE and STRIP are required pngrtran will effectively cancel the
|
| + * latter by doing SCALE first. This is ok and allows apps not to check for
|
| + * which is supported to get the right answer.
|
| + */
|
| + if ((transforms & PNG_TRANSFORM_STRIP_16) != 0)
|
| +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
|
| + png_set_strip_16(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_16 not supported");
|
| +#endif
|
| +
|
| + /* Strip alpha bytes from the input data without combining with
|
| + * the background (not recommended).
|
| + */
|
| + if ((transforms & PNG_TRANSFORM_STRIP_ALPHA) != 0)
|
| +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
|
| + png_set_strip_alpha(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_ALPHA not supported");
|
| +#endif
|
| +
|
| + /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
|
| + * byte into separate bytes (useful for paletted and grayscale images).
|
| + */
|
| + if ((transforms & PNG_TRANSFORM_PACKING) != 0)
|
| +#ifdef PNG_READ_PACK_SUPPORTED
|
| + png_set_packing(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
|
| +#endif
|
| +
|
| + /* 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) != 0)
|
| +#ifdef PNG_READ_PACKSWAP_SUPPORTED
|
| + png_set_packswap(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
|
| +#endif
|
| +
|
| + /* 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) != 0)
|
| +#ifdef PNG_READ_EXPAND_SUPPORTED
|
| + png_set_expand(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND not supported");
|
| +#endif
|
| +
|
| + /* We don't handle background color or gamma transformation or quantizing.
|
| + */
|
| +
|
| + /* Invert monochrome files to have 0 as white and 1 as black
|
| + */
|
| + if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
|
| +#ifdef PNG_READ_INVERT_SUPPORTED
|
| + png_set_invert_mono(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
|
| +#endif
|
| +
|
| + /* 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) != 0)
|
| +#ifdef PNG_READ_SHIFT_SUPPORTED
|
| + if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
|
| + png_set_shift(png_ptr, &info_ptr->sig_bit);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
|
| +#endif
|
| +
|
| + /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
|
| + if ((transforms & PNG_TRANSFORM_BGR) != 0)
|
| +#ifdef PNG_READ_BGR_SUPPORTED
|
| + png_set_bgr(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
|
| +#endif
|
| +
|
| + /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
|
| + if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
|
| +#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
|
| + png_set_swap_alpha(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
|
| +#endif
|
| +
|
| + /* Swap bytes of 16-bit files to least significant byte first */
|
| + if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
|
| +#ifdef PNG_READ_SWAP_SUPPORTED
|
| + png_set_swap(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
|
| +#endif
|
| +
|
| +/* Added at libpng-1.2.41 */
|
| + /* Invert the alpha channel from opacity to transparency */
|
| + if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
|
| +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
|
| + png_set_invert_alpha(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
|
| +#endif
|
| +
|
| +/* Added at libpng-1.2.41 */
|
| + /* Expand grayscale image to RGB */
|
| + if ((transforms & PNG_TRANSFORM_GRAY_TO_RGB) != 0)
|
| +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
| + png_set_gray_to_rgb(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_GRAY_TO_RGB not supported");
|
| +#endif
|
| +
|
| +/* Added at libpng-1.5.4 */
|
| + if ((transforms & PNG_TRANSFORM_EXPAND_16) != 0)
|
| +#ifdef PNG_READ_EXPAND_16_SUPPORTED
|
| + png_set_expand_16(png_ptr);
|
| +#else
|
| + png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND_16 not supported");
|
| +#endif
|
| +
|
| + /* We don't handle adding filler bytes */
|
| +
|
| + /* We use png_read_image and rely on that for interlace handling, but we also
|
| + * call png_read_update_info therefore must turn on interlace handling now:
|
| + */
|
| + (void)png_set_interlace_handling(png_ptr);
|
| +
|
| + /* 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 ------------------- */
|
| +
|
| + png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
|
| + if (info_ptr->row_pointers == NULL)
|
| + {
|
| + png_uint_32 iptr;
|
| +
|
| + info_ptr->row_pointers = png_voidcast(png_bytepp, png_malloc(png_ptr,
|
| + info_ptr->height * (sizeof (png_bytep))));
|
| +
|
| + for (iptr=0; iptr<info_ptr->height; iptr++)
|
| + info_ptr->row_pointers[iptr] = NULL;
|
| +
|
| + info_ptr->free_me |= PNG_FREE_ROWS;
|
| +
|
| + for (iptr = 0; iptr < info_ptr->height; iptr++)
|
| + info_ptr->row_pointers[iptr] = png_voidcast(png_bytep,
|
| + png_malloc(png_ptr, info_ptr->rowbytes));
|
| + }
|
| +
|
| + 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);
|
| +
|
| + PNG_UNUSED(params)
|
| +}
|
| +#endif /* INFO_IMAGE */
|
| +#endif /* SEQUENTIAL_READ */
|
| +
|
| +#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
|
| +/* SIMPLIFIED READ
|
| + *
|
| + * This code currently relies on the sequential reader, though it could easily
|
| + * be made to work with the progressive one.
|
| + */
|
| +/* Arguments to png_image_finish_read: */
|
| +
|
| +/* Encoding of PNG data (used by the color-map code) */
|
| +# define P_NOTSET 0 /* File encoding not yet known */
|
| +# define P_sRGB 1 /* 8-bit encoded to sRGB gamma */
|
| +# define P_LINEAR 2 /* 16-bit linear: not encoded, NOT pre-multiplied! */
|
| +# define P_FILE 3 /* 8-bit encoded to file gamma, not sRGB or linear */
|
| +# define P_LINEAR8 4 /* 8-bit linear: only from a file value */
|
| +
|
| +/* Color-map processing: after libpng has run on the PNG image further
|
| + * processing may be needed to convert the data to color-map indices.
|
| + */
|
| +#define PNG_CMAP_NONE 0
|
| +#define PNG_CMAP_GA 1 /* Process GA data to a color-map with alpha */
|
| +#define PNG_CMAP_TRANS 2 /* Process GA data to a background index */
|
| +#define PNG_CMAP_RGB 3 /* Process RGB data */
|
| +#define PNG_CMAP_RGB_ALPHA 4 /* Process RGBA data */
|
| +
|
| +/* The following document where the background is for each processing case. */
|
| +#define PNG_CMAP_NONE_BACKGROUND 256
|
| +#define PNG_CMAP_GA_BACKGROUND 231
|
| +#define PNG_CMAP_TRANS_BACKGROUND 254
|
| +#define PNG_CMAP_RGB_BACKGROUND 256
|
| +#define PNG_CMAP_RGB_ALPHA_BACKGROUND 216
|
| +
|
| +typedef struct
|
| +{
|
| + /* Arguments: */
|
| + png_imagep image;
|
| + png_voidp buffer;
|
| + png_int_32 row_stride;
|
| + png_voidp colormap;
|
| + png_const_colorp background;
|
| + /* Local variables: */
|
| + png_voidp local_row;
|
| + png_voidp first_row;
|
| + ptrdiff_t row_bytes; /* step between rows */
|
| + int file_encoding; /* E_ values above */
|
| + png_fixed_point gamma_to_linear; /* For P_FILE, reciprocal of gamma */
|
| + int colormap_processing; /* PNG_CMAP_ values above */
|
| +} png_image_read_control;
|
| +
|
| +/* Do all the *safe* initialization - 'safe' means that png_error won't be
|
| + * called, so setting up the jmp_buf is not required. This means that anything
|
| + * called from here must *not* call png_malloc - it has to call png_malloc_warn
|
| + * instead so that control is returned safely back to this routine.
|
| + */
|
| +static int
|
| +png_image_read_init(png_imagep image)
|
| +{
|
| + if (image->opaque == NULL)
|
| + {
|
| + png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, image,
|
| + png_safe_error, png_safe_warning);
|
| +
|
| + /* And set the rest of the structure to NULL to ensure that the various
|
| + * fields are consistent.
|
| + */
|
| + memset(image, 0, (sizeof *image));
|
| + image->version = PNG_IMAGE_VERSION;
|
| +
|
| + if (png_ptr != NULL)
|
| + {
|
| + png_infop info_ptr = png_create_info_struct(png_ptr);
|
| +
|
| + if (info_ptr != NULL)
|
| + {
|
| + png_controlp control = png_voidcast(png_controlp,
|
| + png_malloc_warn(png_ptr, (sizeof *control)));
|
| +
|
| + if (control != NULL)
|
| + {
|
| + memset(control, 0, (sizeof *control));
|
| +
|
| + control->png_ptr = png_ptr;
|
| + control->info_ptr = info_ptr;
|
| + control->for_write = 0;
|
| +
|
| + image->opaque = control;
|
| + return 1;
|
| + }
|
| +
|
| + /* Error clean up */
|
| + png_destroy_info_struct(png_ptr, &info_ptr);
|
| + }
|
| +
|
| + png_destroy_read_struct(&png_ptr, NULL, NULL);
|
| + }
|
| +
|
| + return png_image_error(image, "png_image_read: out of memory");
|
| + }
|
| +
|
| + return png_image_error(image, "png_image_read: opaque pointer not NULL");
|
| +}
|
| +
|
| +/* Utility to find the base format of a PNG file from a png_struct. */
|
| +static png_uint_32
|
| +png_image_format(png_structrp png_ptr)
|
| +{
|
| + png_uint_32 format = 0;
|
| +
|
| + if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
|
| + format |= PNG_FORMAT_FLAG_COLOR;
|
| +
|
| + if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
|
| + format |= PNG_FORMAT_FLAG_ALPHA;
|
| +
|
| + /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS
|
| + * sets the png_struct fields; that's all we are interested in here. The
|
| + * precise interaction with an app call to png_set_tRNS and PNG file reading
|
| + * is unclear.
|
| + */
|
| + else if (png_ptr->num_trans > 0)
|
| + format |= PNG_FORMAT_FLAG_ALPHA;
|
| +
|
| + if (png_ptr->bit_depth == 16)
|
| + format |= PNG_FORMAT_FLAG_LINEAR;
|
| +
|
| + if ((png_ptr->color_type & PNG_COLOR_MASK_PALETTE) != 0)
|
| + format |= PNG_FORMAT_FLAG_COLORMAP;
|
| +
|
| + return format;
|
| +}
|
| +
|
| +/* Is the given gamma significantly different from sRGB? The test is the same
|
| + * one used in pngrtran.c when deciding whether to do gamma correction. The
|
| + * arithmetic optimizes the division by using the fact that the inverse of the
|
| + * file sRGB gamma is 2.2
|
| + */
|
| +static int
|
| +png_gamma_not_sRGB(png_fixed_point g)
|
| +{
|
| + if (g < PNG_FP_1)
|
| + {
|
| + /* An uninitialized gamma is assumed to be sRGB for the simplified API. */
|
| + if (g == 0)
|
| + return 0;
|
| +
|
| + return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */);
|
| + }
|
| +
|
| + return 1;
|
| +}
|
| +
|
| +/* Do the main body of a 'png_image_begin_read' function; read the PNG file
|
| + * header and fill in all the information. This is executed in a safe context,
|
| + * unlike the init routine above.
|
| + */
|
| +static int
|
| +png_image_read_header(png_voidp argument)
|
| +{
|
| + png_imagep image = png_voidcast(png_imagep, argument);
|
| + png_structrp png_ptr = image->opaque->png_ptr;
|
| + png_inforp info_ptr = image->opaque->info_ptr;
|
| +
|
| + png_set_benign_errors(png_ptr, 1/*warn*/);
|
| + png_read_info(png_ptr, info_ptr);
|
| +
|
| + /* Do this the fast way; just read directly out of png_struct. */
|
| + image->width = png_ptr->width;
|
| + image->height = png_ptr->height;
|
| +
|
| + {
|
| + png_uint_32 format = png_image_format(png_ptr);
|
| +
|
| + image->format = format;
|
| +
|
| +#ifdef PNG_COLORSPACE_SUPPORTED
|
| + /* Does the colorspace match sRGB? If there is no color endpoint
|
| + * (colorant) information assume yes, otherwise require the
|
| + * 'ENDPOINTS_MATCHP_sRGB' colorspace flag to have been set. If the
|
| + * colorspace has been determined to be invalid ignore it.
|
| + */
|
| + if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && ((png_ptr->colorspace.flags
|
| + & (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB|
|
| + PNG_COLORSPACE_INVALID)) == PNG_COLORSPACE_HAVE_ENDPOINTS))
|
| + image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB;
|
| +#endif
|
| + }
|
| +
|
| + /* We need the maximum number of entries regardless of the format the
|
| + * application sets here.
|
| + */
|
| + {
|
| + png_uint_32 cmap_entries;
|
| +
|
| + switch (png_ptr->color_type)
|
| + {
|
| + case PNG_COLOR_TYPE_GRAY:
|
| + cmap_entries = 1U << png_ptr->bit_depth;
|
| + break;
|
| +
|
| + case PNG_COLOR_TYPE_PALETTE:
|
| + cmap_entries = png_ptr->num_palette;
|
| + break;
|
| +
|
| + default:
|
| + cmap_entries = 256;
|
| + break;
|
| + }
|
| +
|
| + if (cmap_entries > 256)
|
| + cmap_entries = 256;
|
| +
|
| + image->colormap_entries = cmap_entries;
|
| + }
|
| +
|
| + return 1;
|
| +}
|
| +
|
| +#ifdef PNG_STDIO_SUPPORTED
|
| +int PNGAPI
|
| +png_image_begin_read_from_stdio(png_imagep image, FILE* file)
|
| +{
|
| + if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
| + {
|
| + if (file != NULL)
|
| + {
|
| + if (png_image_read_init(image) != 0)
|
| + {
|
| + /* This is slightly evil, but png_init_io doesn't do anything other
|
| + * than this and we haven't changed the standard IO functions so
|
| + * this saves a 'safe' function.
|
| + */
|
| + image->opaque->png_ptr->io_ptr = file;
|
| + return png_safe_execute(image, png_image_read_header, image);
|
| + }
|
| + }
|
| +
|
| + else
|
| + return png_image_error(image,
|
| + "png_image_begin_read_from_stdio: invalid argument");
|
| + }
|
| +
|
| + else if (image != NULL)
|
| + return png_image_error(image,
|
| + "png_image_begin_read_from_stdio: incorrect PNG_IMAGE_VERSION");
|
| +
|
| + return 0;
|
| +}
|
| +
|
| +int PNGAPI
|
| +png_image_begin_read_from_file(png_imagep image, const char *file_name)
|
| +{
|
| + if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
| + {
|
| + if (file_name != NULL)
|
| + {
|
| + FILE *fp = fopen(file_name, "rb");
|
| +
|
| + if (fp != NULL)
|
| + {
|
| + if (png_image_read_init(image) != 0)
|
| + {
|
| + image->opaque->png_ptr->io_ptr = fp;
|
| + image->opaque->owned_file = 1;
|
| + return png_safe_execute(image, png_image_read_header, image);
|
| + }
|
| +
|
| + /* Clean up: just the opened file. */
|
| + (void)fclose(fp);
|
| + }
|
| +
|
| + else
|
| + return png_image_error(image, strerror(errno));
|
| + }
|
| +
|
| + else
|
| + return png_image_error(image,
|
| + "png_image_begin_read_from_file: invalid argument");
|
| + }
|
| +
|
| + else if (image != NULL)
|
| + return png_image_error(image,
|
| + "png_image_begin_read_from_file: incorrect PNG_IMAGE_VERSION");
|
| +
|
| + return 0;
|
| +}
|
| +#endif /* STDIO */
|
| +
|
| +static void PNGCBAPI
|
| +png_image_memory_read(png_structp png_ptr, png_bytep out, png_size_t need)
|
| +{
|
| + if (png_ptr != NULL)
|
| + {
|
| + png_imagep image = png_voidcast(png_imagep, png_ptr->io_ptr);
|
| + if (image != NULL)
|
| + {
|
| + png_controlp cp = image->opaque;
|
| + if (cp != NULL)
|
| + {
|
| + png_const_bytep memory = cp->memory;
|
| + png_size_t size = cp->size;
|
| +
|
| + if (memory != NULL && size >= need)
|
| + {
|
| + memcpy(out, memory, need);
|
| + cp->memory = memory + need;
|
| + cp->size = size - need;
|
| + return;
|
| + }
|
| +
|
| + png_error(png_ptr, "read beyond end of data");
|
| + }
|
| + }
|
| +
|
| + png_error(png_ptr, "invalid memory read");
|
| + }
|
| +}
|
| +
|
| +int PNGAPI png_image_begin_read_from_memory(png_imagep image,
|
| + png_const_voidp memory, png_size_t size)
|
| +{
|
| + if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
| + {
|
| + if (memory != NULL && size > 0)
|
| + {
|
| + if (png_image_read_init(image) != 0)
|
| + {
|
| + /* Now set the IO functions to read from the memory buffer and
|
| + * store it into io_ptr. Again do this in-place to avoid calling a
|
| + * libpng function that requires error handling.
|
| + */
|
| + image->opaque->memory = png_voidcast(png_const_bytep, memory);
|
| + image->opaque->size = size;
|
| + image->opaque->png_ptr->io_ptr = image;
|
| + image->opaque->png_ptr->read_data_fn = png_image_memory_read;
|
| +
|
| + return png_safe_execute(image, png_image_read_header, image);
|
| + }
|
| + }
|
| +
|
| + else
|
| + return png_image_error(image,
|
| + "png_image_begin_read_from_memory: invalid argument");
|
| + }
|
| +
|
| + else if (image != NULL)
|
| + return png_image_error(image,
|
| + "png_image_begin_read_from_memory: incorrect PNG_IMAGE_VERSION");
|
| +
|
| + return 0;
|
| +}
|
| +
|
| +/* Utility function to skip chunks that are not used by the simplified image
|
| + * read functions and an appropriate macro to call it.
|
| + */
|
| +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
| +static void
|
| +png_image_skip_unused_chunks(png_structrp png_ptr)
|
| +{
|
| + /* Prepare the reader to ignore all recognized chunks whose data will not
|
| + * be used, i.e., all chunks recognized by libpng except for those
|
| + * involved in basic image reading:
|
| + *
|
| + * IHDR, PLTE, IDAT, IEND
|
| + *
|
| + * Or image data handling:
|
| + *
|
| + * tRNS, bKGD, gAMA, cHRM, sRGB, [iCCP] and sBIT.
|
| + *
|
| + * This provides a small performance improvement and eliminates any
|
| + * potential vulnerability to security problems in the unused chunks.
|
| + *
|
| + * At present the iCCP chunk data isn't used, so iCCP chunk can be ignored
|
| + * too. This allows the simplified API to be compiled without iCCP support,
|
| + * however if the support is there the chunk is still checked to detect
|
| + * errors (which are unfortunately quite common.)
|
| + */
|
| + {
|
| + static PNG_CONST png_byte chunks_to_process[] = {
|
| + 98, 75, 71, 68, '\0', /* bKGD */
|
| + 99, 72, 82, 77, '\0', /* cHRM */
|
| + 103, 65, 77, 65, '\0', /* gAMA */
|
| +# ifdef PNG_READ_iCCP_SUPPORTED
|
| + 105, 67, 67, 80, '\0', /* iCCP */
|
| +# endif
|
| + 115, 66, 73, 84, '\0', /* sBIT */
|
| + 115, 82, 71, 66, '\0', /* sRGB */
|
| + };
|
| +
|
| + /* Ignore unknown chunks and all other chunks except for the
|
| + * IHDR, PLTE, tRNS, IDAT, and IEND chunks.
|
| + */
|
| + png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER,
|
| + NULL, -1);
|
| +
|
| + /* But do not ignore image data handling chunks */
|
| + png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT,
|
| + chunks_to_process, (int)/*SAFE*/(sizeof chunks_to_process)/5);
|
| + }
|
| +}
|
| +
|
| +# define PNG_SKIP_CHUNKS(p) png_image_skip_unused_chunks(p)
|
| +#else
|
| +# define PNG_SKIP_CHUNKS(p) ((void)0)
|
| +#endif /* HANDLE_AS_UNKNOWN */
|
| +
|
| +/* The following macro gives the exact rounded answer for all values in the
|
| + * range 0..255 (it actually divides by 51.2, but the rounding still generates
|
| + * the correct numbers 0..5
|
| + */
|
| +#define PNG_DIV51(v8) (((v8) * 5 + 130) >> 8)
|
| +
|
| +/* Utility functions to make particular color-maps */
|
| +static void
|
| +set_file_encoding(png_image_read_control *display)
|
| +{
|
| + png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma;
|
| + if (png_gamma_significant(g) != 0)
|
| + {
|
| + if (png_gamma_not_sRGB(g) != 0)
|
| + {
|
| + display->file_encoding = P_FILE;
|
| + display->gamma_to_linear = png_reciprocal(g);
|
| + }
|
| +
|
| + else
|
| + display->file_encoding = P_sRGB;
|
| + }
|
| +
|
| + else
|
| + display->file_encoding = P_LINEAR8;
|
| +}
|
| +
|
| +static unsigned int
|
| +decode_gamma(png_image_read_control *display, png_uint_32 value, int encoding)
|
| +{
|
| + if (encoding == P_FILE) /* double check */
|
| + encoding = display->file_encoding;
|
| +
|
| + if (encoding == P_NOTSET) /* must be the file encoding */
|
| + {
|
| + set_file_encoding(display);
|
| + encoding = display->file_encoding;
|
| + }
|
| +
|
| + switch (encoding)
|
| + {
|
| + case P_FILE:
|
| + value = png_gamma_16bit_correct(value*257, display->gamma_to_linear);
|
| + break;
|
| +
|
| + case P_sRGB:
|
| + value = png_sRGB_table[value];
|
| + break;
|
| +
|
| + case P_LINEAR:
|
| + break;
|
| +
|
| + case P_LINEAR8:
|
| + value *= 257;
|
| + break;
|
| +
|
| +#ifdef __GNUC__
|
| + default:
|
| + png_error(display->image->opaque->png_ptr,
|
| + "unexpected encoding (internal error)");
|
| +#endif
|
| + }
|
| +
|
| + return value;
|
| +}
|
| +
|
| +static png_uint_32
|
| +png_colormap_compose(png_image_read_control *display,
|
| + png_uint_32 foreground, int foreground_encoding, png_uint_32 alpha,
|
| + png_uint_32 background, int encoding)
|
| +{
|
| + /* The file value is composed on the background, the background has the given
|
| + * encoding and so does the result, the file is encoded with P_FILE and the
|
| + * file and alpha are 8-bit values. The (output) encoding will always be
|
| + * P_LINEAR or P_sRGB.
|
| + */
|
| + png_uint_32 f = decode_gamma(display, foreground, foreground_encoding);
|
| + png_uint_32 b = decode_gamma(display, background, encoding);
|
| +
|
| + /* The alpha is always an 8-bit value (it comes from the palette), the value
|
| + * scaled by 255 is what PNG_sRGB_FROM_LINEAR requires.
|
| + */
|
| + f = f * alpha + b * (255-alpha);
|
| +
|
| + if (encoding == P_LINEAR)
|
| + {
|
| + /* Scale to 65535; divide by 255, approximately (in fact this is extremely
|
| + * accurate, it divides by 255.00000005937181414556, with no overflow.)
|
| + */
|
| + f *= 257; /* Now scaled by 65535 */
|
| + f += f >> 16;
|
| + f = (f+32768) >> 16;
|
| + }
|
| +
|
| + else /* P_sRGB */
|
| + f = PNG_sRGB_FROM_LINEAR(f);
|
| +
|
| + return f;
|
| +}
|
| +
|
| +/* NOTE: P_LINEAR values to this routine must be 16-bit, but P_FILE values must
|
| + * be 8-bit.
|
| + */
|
| +static void
|
| +png_create_colormap_entry(png_image_read_control *display,
|
| + png_uint_32 ip, png_uint_32 red, png_uint_32 green, png_uint_32 blue,
|
| + png_uint_32 alpha, int encoding)
|
| +{
|
| + png_imagep image = display->image;
|
| + const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
|
| + P_LINEAR : P_sRGB;
|
| + const int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 &&
|
| + (red != green || green != blue);
|
| +
|
| + if (ip > 255)
|
| + png_error(image->opaque->png_ptr, "color-map index out of range");
|
| +
|
| + /* Update the cache with whether the file gamma is significantly different
|
| + * from sRGB.
|
| + */
|
| + if (encoding == P_FILE)
|
| + {
|
| + if (display->file_encoding == P_NOTSET)
|
| + set_file_encoding(display);
|
| +
|
| + /* Note that the cached value may be P_FILE too, but if it is then the
|
| + * gamma_to_linear member has been set.
|
| + */
|
| + encoding = display->file_encoding;
|
| + }
|
| +
|
| + if (encoding == P_FILE)
|
| + {
|
| + png_fixed_point g = display->gamma_to_linear;
|
| +
|
| + red = png_gamma_16bit_correct(red*257, g);
|
| + green = png_gamma_16bit_correct(green*257, g);
|
| + blue = png_gamma_16bit_correct(blue*257, g);
|
| +
|
| + if (convert_to_Y != 0 || output_encoding == P_LINEAR)
|
| + {
|
| + alpha *= 257;
|
| + encoding = P_LINEAR;
|
| + }
|
| +
|
| + else
|
| + {
|
| + red = PNG_sRGB_FROM_LINEAR(red * 255);
|
| + green = PNG_sRGB_FROM_LINEAR(green * 255);
|
| + blue = PNG_sRGB_FROM_LINEAR(blue * 255);
|
| + encoding = P_sRGB;
|
| + }
|
| + }
|
| +
|
| + else if (encoding == P_LINEAR8)
|
| + {
|
| + /* This encoding occurs quite frequently in test cases because PngSuite
|
| + * includes a gAMA 1.0 chunk with most images.
|
| + */
|
| + red *= 257;
|
| + green *= 257;
|
| + blue *= 257;
|
| + alpha *= 257;
|
| + encoding = P_LINEAR;
|
| + }
|
| +
|
| + else if (encoding == P_sRGB &&
|
| + (convert_to_Y != 0 || output_encoding == P_LINEAR))
|
| + {
|
| + /* The values are 8-bit sRGB values, but must be converted to 16-bit
|
| + * linear.
|
| + */
|
| + red = png_sRGB_table[red];
|
| + green = png_sRGB_table[green];
|
| + blue = png_sRGB_table[blue];
|
| + alpha *= 257;
|
| + encoding = P_LINEAR;
|
| + }
|
| +
|
| + /* This is set if the color isn't gray but the output is. */
|
| + if (encoding == P_LINEAR)
|
| + {
|
| + if (convert_to_Y != 0)
|
| + {
|
| + /* NOTE: these values are copied from png_do_rgb_to_gray */
|
| + png_uint_32 y = (png_uint_32)6968 * red + (png_uint_32)23434 * green +
|
| + (png_uint_32)2366 * blue;
|
| +
|
| + if (output_encoding == P_LINEAR)
|
| + y = (y + 16384) >> 15;
|
| +
|
| + else
|
| + {
|
| + /* y is scaled by 32768, we need it scaled by 255: */
|
| + y = (y + 128) >> 8;
|
| + y *= 255;
|
| + y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7);
|
| + alpha = PNG_DIV257(alpha);
|
| + encoding = P_sRGB;
|
| + }
|
| +
|
| + blue = red = green = y;
|
| + }
|
| +
|
| + else if (output_encoding == P_sRGB)
|
| + {
|
| + red = PNG_sRGB_FROM_LINEAR(red * 255);
|
| + green = PNG_sRGB_FROM_LINEAR(green * 255);
|
| + blue = PNG_sRGB_FROM_LINEAR(blue * 255);
|
| + alpha = PNG_DIV257(alpha);
|
| + encoding = P_sRGB;
|
| + }
|
| + }
|
| +
|
| + if (encoding != output_encoding)
|
| + png_error(image->opaque->png_ptr, "bad encoding (internal error)");
|
| +
|
| + /* Store the value. */
|
| + {
|
| +# ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
| + const int afirst = (image->format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
|
| + (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
|
| +# else
|
| +# define afirst 0
|
| +# endif
|
| +# ifdef PNG_FORMAT_BGR_SUPPORTED
|
| + const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
|
| +# else
|
| +# define bgr 0
|
| +# endif
|
| +
|
| + if (output_encoding == P_LINEAR)
|
| + {
|
| + png_uint_16p entry = png_voidcast(png_uint_16p, display->colormap);
|
| +
|
| + entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
|
| +
|
| + /* The linear 16-bit values must be pre-multiplied by the alpha channel
|
| + * value, if less than 65535 (this is, effectively, composite on black
|
| + * if the alpha channel is removed.)
|
| + */
|
| + switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
|
| + {
|
| + case 4:
|
| + entry[afirst ? 0 : 3] = (png_uint_16)alpha;
|
| + /* FALL THROUGH */
|
| +
|
| + case 3:
|
| + if (alpha < 65535)
|
| + {
|
| + if (alpha > 0)
|
| + {
|
| + blue = (blue * alpha + 32767U)/65535U;
|
| + green = (green * alpha + 32767U)/65535U;
|
| + red = (red * alpha + 32767U)/65535U;
|
| + }
|
| +
|
| + else
|
| + red = green = blue = 0;
|
| + }
|
| + entry[afirst + (2 ^ bgr)] = (png_uint_16)blue;
|
| + entry[afirst + 1] = (png_uint_16)green;
|
| + entry[afirst + bgr] = (png_uint_16)red;
|
| + break;
|
| +
|
| + case 2:
|
| + entry[1 ^ afirst] = (png_uint_16)alpha;
|
| + /* FALL THROUGH */
|
| +
|
| + case 1:
|
| + if (alpha < 65535)
|
| + {
|
| + if (alpha > 0)
|
| + green = (green * alpha + 32767U)/65535U;
|
| +
|
| + else
|
| + green = 0;
|
| + }
|
| + entry[afirst] = (png_uint_16)green;
|
| + break;
|
| +
|
| + default:
|
| + break;
|
| + }
|
| + }
|
| +
|
| + else /* output encoding is P_sRGB */
|
| + {
|
| + png_bytep entry = png_voidcast(png_bytep, display->colormap);
|
| +
|
| + entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
|
| +
|
| + switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
|
| + {
|
| + case 4:
|
| + entry[afirst ? 0 : 3] = (png_byte)alpha;
|
| + case 3:
|
| + entry[afirst + (2 ^ bgr)] = (png_byte)blue;
|
| + entry[afirst + 1] = (png_byte)green;
|
| + entry[afirst + bgr] = (png_byte)red;
|
| + break;
|
| +
|
| + case 2:
|
| + entry[1 ^ afirst] = (png_byte)alpha;
|
| + case 1:
|
| + entry[afirst] = (png_byte)green;
|
| + break;
|
| +
|
| + default:
|
| + break;
|
| + }
|
| + }
|
| +
|
| +# ifdef afirst
|
| +# undef afirst
|
| +# endif
|
| +# ifdef bgr
|
| +# undef bgr
|
| +# endif
|
| + }
|
| +}
|
| +
|
| +static int
|
| +make_gray_file_colormap(png_image_read_control *display)
|
| +{
|
| + unsigned int i;
|
| +
|
| + for (i=0; i<256; ++i)
|
| + png_create_colormap_entry(display, i, i, i, i, 255, P_FILE);
|
| +
|
| + return i;
|
| +}
|
| +
|
| +static int
|
| +make_gray_colormap(png_image_read_control *display)
|
| +{
|
| + unsigned int i;
|
| +
|
| + for (i=0; i<256; ++i)
|
| + png_create_colormap_entry(display, i, i, i, i, 255, P_sRGB);
|
| +
|
| + return i;
|
| +}
|
| +#define PNG_GRAY_COLORMAP_ENTRIES 256
|
| +
|
| +static int
|
| +make_ga_colormap(png_image_read_control *display)
|
| +{
|
| + unsigned int i, a;
|
| +
|
| + /* Alpha is retained, the output will be a color-map with entries
|
| + * selected by six levels of alpha. One transparent entry, 6 gray
|
| + * levels for all the intermediate alpha values, leaving 230 entries
|
| + * for the opaque grays. The color-map entries are the six values
|
| + * [0..5]*51, the GA processing uses PNG_DIV51(value) to find the
|
| + * relevant entry.
|
| + *
|
| + * if (alpha > 229) // opaque
|
| + * {
|
| + * // The 231 entries are selected to make the math below work:
|
| + * base = 0;
|
| + * entry = (231 * gray + 128) >> 8;
|
| + * }
|
| + * else if (alpha < 26) // transparent
|
| + * {
|
| + * base = 231;
|
| + * entry = 0;
|
| + * }
|
| + * else // partially opaque
|
| + * {
|
| + * base = 226 + 6 * PNG_DIV51(alpha);
|
| + * entry = PNG_DIV51(gray);
|
| + * }
|
| + */
|
| + i = 0;
|
| + while (i < 231)
|
| + {
|
| + unsigned int gray = (i * 256 + 115) / 231;
|
| + png_create_colormap_entry(display, i++, gray, gray, gray, 255, P_sRGB);
|
| + }
|
| +
|
| + /* 255 is used here for the component values for consistency with the code
|
| + * that undoes premultiplication in pngwrite.c.
|
| + */
|
| + png_create_colormap_entry(display, i++, 255, 255, 255, 0, P_sRGB);
|
| +
|
| + for (a=1; a<5; ++a)
|
| + {
|
| + unsigned int g;
|
| +
|
| + for (g=0; g<6; ++g)
|
| + png_create_colormap_entry(display, i++, g*51, g*51, g*51, a*51,
|
| + P_sRGB);
|
| + }
|
| +
|
| + return i;
|
| +}
|
| +
|
| +#define PNG_GA_COLORMAP_ENTRIES 256
|
| +
|
| +static int
|
| +make_rgb_colormap(png_image_read_control *display)
|
| +{
|
| + unsigned int i, r;
|
| +
|
| + /* Build a 6x6x6 opaque RGB cube */
|
| + for (i=r=0; r<6; ++r)
|
| + {
|
| + unsigned int g;
|
| +
|
| + for (g=0; g<6; ++g)
|
| + {
|
| + unsigned int b;
|
| +
|
| + for (b=0; b<6; ++b)
|
| + png_create_colormap_entry(display, i++, r*51, g*51, b*51, 255,
|
| + P_sRGB);
|
| + }
|
| + }
|
| +
|
| + return i;
|
| +}
|
| +
|
| +#define PNG_RGB_COLORMAP_ENTRIES 216
|
| +
|
| +/* Return a palette index to the above palette given three 8-bit sRGB values. */
|
| +#define PNG_RGB_INDEX(r,g,b) \
|
| + ((png_byte)(6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b)))
|
| +
|
| +static int
|
| +png_image_read_colormap(png_voidp argument)
|
| +{
|
| + png_image_read_control *display =
|
| + png_voidcast(png_image_read_control*, argument);
|
| + const png_imagep image = display->image;
|
| +
|
| + const png_structrp png_ptr = image->opaque->png_ptr;
|
| + const png_uint_32 output_format = image->format;
|
| + const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
|
| + P_LINEAR : P_sRGB;
|
| +
|
| + unsigned int cmap_entries;
|
| + unsigned int output_processing; /* Output processing option */
|
| + unsigned int data_encoding = P_NOTSET; /* Encoding libpng must produce */
|
| +
|
| + /* Background information; the background color and the index of this color
|
| + * in the color-map if it exists (else 256).
|
| + */
|
| + unsigned int background_index = 256;
|
| + png_uint_32 back_r, back_g, back_b;
|
| +
|
| + /* Flags to accumulate things that need to be done to the input. */
|
| + int expand_tRNS = 0;
|
| +
|
| + /* Exclude the NYI feature of compositing onto a color-mapped buffer; it is
|
| + * very difficult to do, the results look awful, and it is difficult to see
|
| + * what possible use it is because the application can't control the
|
| + * color-map.
|
| + */
|
| + if (((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0 ||
|
| + png_ptr->num_trans > 0) /* alpha in input */ &&
|
| + ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) /* no alpha in output */)
|
| + {
|
| + if (output_encoding == P_LINEAR) /* compose on black */
|
| + back_b = back_g = back_r = 0;
|
| +
|
| + else if (display->background == NULL /* no way to remove it */)
|
| + png_error(png_ptr,
|
| + "a background color must be supplied to remove alpha/transparency");
|
| +
|
| + /* Get a copy of the background color (this avoids repeating the checks
|
| + * below.) The encoding is 8-bit sRGB or 16-bit linear, depending on the
|
| + * output format.
|
| + */
|
| + else
|
| + {
|
| + back_g = display->background->green;
|
| + if ((output_format & PNG_FORMAT_FLAG_COLOR) != 0)
|
| + {
|
| + back_r = display->background->red;
|
| + back_b = display->background->blue;
|
| + }
|
| + else
|
| + back_b = back_r = back_g;
|
| + }
|
| + }
|
| +
|
| + else if (output_encoding == P_LINEAR)
|
| + back_b = back_r = back_g = 65535;
|
| +
|
| + else
|
| + back_b = back_r = back_g = 255;
|
| +
|
| + /* Default the input file gamma if required - this is necessary because
|
| + * libpng assumes that if no gamma information is present the data is in the
|
| + * output format, but the simplified API deduces the gamma from the input
|
| + * format.
|
| + */
|
| + if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) == 0)
|
| + {
|
| + /* Do this directly, not using the png_colorspace functions, to ensure
|
| + * that it happens even if the colorspace is invalid (though probably if
|
| + * it is the setting will be ignored) Note that the same thing can be
|
| + * achieved at the application interface with png_set_gAMA.
|
| + */
|
| + if (png_ptr->bit_depth == 16 &&
|
| + (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
|
| + png_ptr->colorspace.gamma = PNG_GAMMA_LINEAR;
|
| +
|
| + else
|
| + png_ptr->colorspace.gamma = PNG_GAMMA_sRGB_INVERSE;
|
| +
|
| + png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
|
| + }
|
| +
|
| + /* Decide what to do based on the PNG color type of the input data. The
|
| + * utility function png_create_colormap_entry deals with most aspects of the
|
| + * output transformations; this code works out how to produce bytes of
|
| + * color-map entries from the original format.
|
| + */
|
| + switch (png_ptr->color_type)
|
| + {
|
| + case PNG_COLOR_TYPE_GRAY:
|
| + if (png_ptr->bit_depth <= 8)
|
| + {
|
| + /* There at most 256 colors in the output, regardless of
|
| + * transparency.
|
| + */
|
| + unsigned int step, i, val, trans = 256/*ignore*/, back_alpha = 0;
|
| +
|
| + cmap_entries = 1U << png_ptr->bit_depth;
|
| + if (cmap_entries > image->colormap_entries)
|
| + png_error(png_ptr, "gray[8] color-map: too few entries");
|
| +
|
| + step = 255 / (cmap_entries - 1);
|
| + output_processing = PNG_CMAP_NONE;
|
| +
|
| + /* If there is a tRNS chunk then this either selects a transparent
|
| + * value or, if the output has no alpha, the background color.
|
| + */
|
| + if (png_ptr->num_trans > 0)
|
| + {
|
| + trans = png_ptr->trans_color.gray;
|
| +
|
| + if ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0)
|
| + back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
|
| + }
|
| +
|
| + /* png_create_colormap_entry just takes an RGBA and writes the
|
| + * corresponding color-map entry using the format from 'image',
|
| + * including the required conversion to sRGB or linear as
|
| + * appropriate. The input values are always either sRGB (if the
|
| + * gamma correction flag is 0) or 0..255 scaled file encoded values
|
| + * (if the function must gamma correct them).
|
| + */
|
| + for (i=val=0; i<cmap_entries; ++i, val += step)
|
| + {
|
| + /* 'i' is a file value. While this will result in duplicated
|
| + * entries for 8-bit non-sRGB encoded files it is necessary to
|
| + * have non-gamma corrected values to do tRNS handling.
|
| + */
|
| + if (i != trans)
|
| + png_create_colormap_entry(display, i, val, val, val, 255,
|
| + P_FILE/*8-bit with file gamma*/);
|
| +
|
| + /* Else this entry is transparent. The colors don't matter if
|
| + * there is an alpha channel (back_alpha == 0), but it does no
|
| + * harm to pass them in; the values are not set above so this
|
| + * passes in white.
|
| + *
|
| + * NOTE: this preserves the full precision of the application
|
| + * supplied background color when it is used.
|
| + */
|
| + else
|
| + png_create_colormap_entry(display, i, back_r, back_g, back_b,
|
| + back_alpha, output_encoding);
|
| + }
|
| +
|
| + /* We need libpng to preserve the original encoding. */
|
| + data_encoding = P_FILE;
|
| +
|
| + /* The rows from libpng, while technically gray values, are now also
|
| + * color-map indices; however, they may need to be expanded to 1
|
| + * byte per pixel. This is what png_set_packing does (i.e., it
|
| + * unpacks the bit values into bytes.)
|
| + */
|
| + if (png_ptr->bit_depth < 8)
|
| + png_set_packing(png_ptr);
|
| + }
|
| +
|
| + else /* bit depth is 16 */
|
| + {
|
| + /* The 16-bit input values can be converted directly to 8-bit gamma
|
| + * encoded values; however, if a tRNS chunk is present 257 color-map
|
| + * entries are required. This means that the extra entry requires
|
| + * special processing; add an alpha channel, sacrifice gray level
|
| + * 254 and convert transparent (alpha==0) entries to that.
|
| + *
|
| + * Use libpng to chop the data to 8 bits. Convert it to sRGB at the
|
| + * same time to minimize quality loss. If a tRNS chunk is present
|
| + * this means libpng must handle it too; otherwise it is impossible
|
| + * to do the exact match on the 16-bit value.
|
| + *
|
| + * If the output has no alpha channel *and* the background color is
|
| + * gray then it is possible to let libpng handle the substitution by
|
| + * ensuring that the corresponding gray level matches the background
|
| + * color exactly.
|
| + */
|
| + data_encoding = P_sRGB;
|
| +
|
| + if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
| + png_error(png_ptr, "gray[16] color-map: too few entries");
|
| +
|
| + cmap_entries = make_gray_colormap(display);
|
| +
|
| + if (png_ptr->num_trans > 0)
|
| + {
|
| + unsigned int back_alpha;
|
| +
|
| + if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + back_alpha = 0;
|
| +
|
| + else
|
| + {
|
| + if (back_r == back_g && back_g == back_b)
|
| + {
|
| + /* Background is gray; no special processing will be
|
| + * required.
|
| + */
|
| + png_color_16 c;
|
| + png_uint_32 gray = back_g;
|
| +
|
| + if (output_encoding == P_LINEAR)
|
| + {
|
| + gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
| +
|
| + /* And make sure the corresponding palette entry
|
| + * matches.
|
| + */
|
| + png_create_colormap_entry(display, gray, back_g, back_g,
|
| + back_g, 65535, P_LINEAR);
|
| + }
|
| +
|
| + /* The background passed to libpng, however, must be the
|
| + * sRGB value.
|
| + */
|
| + c.index = 0; /*unused*/
|
| + c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
| +
|
| + /* NOTE: does this work without expanding tRNS to alpha?
|
| + * It should be the color->gray case below apparently
|
| + * doesn't.
|
| + */
|
| + png_set_background_fixed(png_ptr, &c,
|
| + PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
| + 0/*gamma: not used*/);
|
| +
|
| + output_processing = PNG_CMAP_NONE;
|
| + break;
|
| + }
|
| +#ifdef __COVERITY__
|
| + /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
|
| + * here.
|
| + */
|
| + back_alpha = 255;
|
| +#else
|
| + back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
|
| +#endif
|
| + }
|
| +
|
| + /* output_processing means that the libpng-processed row will be
|
| + * 8-bit GA and it has to be processing to single byte color-map
|
| + * values. Entry 254 is replaced by either a completely
|
| + * transparent entry or by the background color at full
|
| + * precision (and the background color is not a simple gray
|
| + * level in this case.)
|
| + */
|
| + expand_tRNS = 1;
|
| + output_processing = PNG_CMAP_TRANS;
|
| + background_index = 254;
|
| +
|
| + /* And set (overwrite) color-map entry 254 to the actual
|
| + * background color at full precision.
|
| + */
|
| + png_create_colormap_entry(display, 254, back_r, back_g, back_b,
|
| + back_alpha, output_encoding);
|
| + }
|
| +
|
| + else
|
| + output_processing = PNG_CMAP_NONE;
|
| + }
|
| + break;
|
| +
|
| + case PNG_COLOR_TYPE_GRAY_ALPHA:
|
| + /* 8-bit or 16-bit PNG with two channels - gray and alpha. A minimum
|
| + * of 65536 combinations. If, however, the alpha channel is to be
|
| + * removed there are only 256 possibilities if the background is gray.
|
| + * (Otherwise there is a subset of the 65536 possibilities defined by
|
| + * the triangle between black, white and the background color.)
|
| + *
|
| + * Reduce 16-bit files to 8-bit and sRGB encode the result. No need to
|
| + * worry about tRNS matching - tRNS is ignored if there is an alpha
|
| + * channel.
|
| + */
|
| + data_encoding = P_sRGB;
|
| +
|
| + if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + {
|
| + if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
| + png_error(png_ptr, "gray+alpha color-map: too few entries");
|
| +
|
| + cmap_entries = make_ga_colormap(display);
|
| +
|
| + background_index = PNG_CMAP_GA_BACKGROUND;
|
| + output_processing = PNG_CMAP_GA;
|
| + }
|
| +
|
| + else /* alpha is removed */
|
| + {
|
| + /* Alpha must be removed as the PNG data is processed when the
|
| + * background is a color because the G and A channels are
|
| + * independent and the vector addition (non-parallel vectors) is a
|
| + * 2-D problem.
|
| + *
|
| + * This can be reduced to the same algorithm as above by making a
|
| + * colormap containing gray levels (for the opaque grays), a
|
| + * background entry (for a transparent pixel) and a set of four six
|
| + * level color values, one set for each intermediate alpha value.
|
| + * See the comments in make_ga_colormap for how this works in the
|
| + * per-pixel processing.
|
| + *
|
| + * If the background is gray, however, we only need a 256 entry gray
|
| + * level color map. It is sufficient to make the entry generated
|
| + * for the background color be exactly the color specified.
|
| + */
|
| + if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0 ||
|
| + (back_r == back_g && back_g == back_b))
|
| + {
|
| + /* Background is gray; no special processing will be required. */
|
| + png_color_16 c;
|
| + png_uint_32 gray = back_g;
|
| +
|
| + if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
| + png_error(png_ptr, "gray-alpha color-map: too few entries");
|
| +
|
| + cmap_entries = make_gray_colormap(display);
|
| +
|
| + if (output_encoding == P_LINEAR)
|
| + {
|
| + gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
| +
|
| + /* And make sure the corresponding palette entry matches. */
|
| + png_create_colormap_entry(display, gray, back_g, back_g,
|
| + back_g, 65535, P_LINEAR);
|
| + }
|
| +
|
| + /* The background passed to libpng, however, must be the sRGB
|
| + * value.
|
| + */
|
| + c.index = 0; /*unused*/
|
| + c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
| +
|
| + png_set_background_fixed(png_ptr, &c,
|
| + PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
| + 0/*gamma: not used*/);
|
| +
|
| + output_processing = PNG_CMAP_NONE;
|
| + }
|
| +
|
| + else
|
| + {
|
| + png_uint_32 i, a;
|
| +
|
| + /* This is the same as png_make_ga_colormap, above, except that
|
| + * the entries are all opaque.
|
| + */
|
| + if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
| + png_error(png_ptr, "ga-alpha color-map: too few entries");
|
| +
|
| + i = 0;
|
| + while (i < 231)
|
| + {
|
| + png_uint_32 gray = (i * 256 + 115) / 231;
|
| + png_create_colormap_entry(display, i++, gray, gray, gray,
|
| + 255, P_sRGB);
|
| + }
|
| +
|
| + /* NOTE: this preserves the full precision of the application
|
| + * background color.
|
| + */
|
| + background_index = i;
|
| + png_create_colormap_entry(display, i++, back_r, back_g, back_b,
|
| +#ifdef __COVERITY__
|
| + /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
|
| + * here.
|
| + */ 255U,
|
| +#else
|
| + output_encoding == P_LINEAR ? 65535U : 255U,
|
| +#endif
|
| + output_encoding);
|
| +
|
| + /* For non-opaque input composite on the sRGB background - this
|
| + * requires inverting the encoding for each component. The input
|
| + * is still converted to the sRGB encoding because this is a
|
| + * reasonable approximate to the logarithmic curve of human
|
| + * visual sensitivity, at least over the narrow range which PNG
|
| + * represents. Consequently 'G' is always sRGB encoded, while
|
| + * 'A' is linear. We need the linear background colors.
|
| + */
|
| + if (output_encoding == P_sRGB) /* else already linear */
|
| + {
|
| + /* This may produce a value not exactly matching the
|
| + * background, but that's ok because these numbers are only
|
| + * used when alpha != 0
|
| + */
|
| + back_r = png_sRGB_table[back_r];
|
| + back_g = png_sRGB_table[back_g];
|
| + back_b = png_sRGB_table[back_b];
|
| + }
|
| +
|
| + for (a=1; a<5; ++a)
|
| + {
|
| + unsigned int g;
|
| +
|
| + /* PNG_sRGB_FROM_LINEAR expects a 16-bit linear value scaled
|
| + * by an 8-bit alpha value (0..255).
|
| + */
|
| + png_uint_32 alpha = 51 * a;
|
| + png_uint_32 back_rx = (255-alpha) * back_r;
|
| + png_uint_32 back_gx = (255-alpha) * back_g;
|
| + png_uint_32 back_bx = (255-alpha) * back_b;
|
| +
|
| + for (g=0; g<6; ++g)
|
| + {
|
| + png_uint_32 gray = png_sRGB_table[g*51] * alpha;
|
| +
|
| + png_create_colormap_entry(display, i++,
|
| + PNG_sRGB_FROM_LINEAR(gray + back_rx),
|
| + PNG_sRGB_FROM_LINEAR(gray + back_gx),
|
| + PNG_sRGB_FROM_LINEAR(gray + back_bx), 255, P_sRGB);
|
| + }
|
| + }
|
| +
|
| + cmap_entries = i;
|
| + output_processing = PNG_CMAP_GA;
|
| + }
|
| + }
|
| + break;
|
| +
|
| + case PNG_COLOR_TYPE_RGB:
|
| + case PNG_COLOR_TYPE_RGB_ALPHA:
|
| + /* Exclude the case where the output is gray; we can always handle this
|
| + * with the cases above.
|
| + */
|
| + if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0)
|
| + {
|
| + /* The color-map will be grayscale, so we may as well convert the
|
| + * input RGB values to a simple grayscale and use the grayscale
|
| + * code above.
|
| + *
|
| + * NOTE: calling this apparently damages the recognition of the
|
| + * transparent color in background color handling; call
|
| + * png_set_tRNS_to_alpha before png_set_background_fixed.
|
| + */
|
| + png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, -1,
|
| + -1);
|
| + data_encoding = P_sRGB;
|
| +
|
| + /* The output will now be one or two 8-bit gray or gray+alpha
|
| + * channels. The more complex case arises when the input has alpha.
|
| + */
|
| + if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
| + png_ptr->num_trans > 0) &&
|
| + (output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + {
|
| + /* Both input and output have an alpha channel, so no background
|
| + * processing is required; just map the GA bytes to the right
|
| + * color-map entry.
|
| + */
|
| + expand_tRNS = 1;
|
| +
|
| + if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
| + png_error(png_ptr, "rgb[ga] color-map: too few entries");
|
| +
|
| + cmap_entries = make_ga_colormap(display);
|
| + background_index = PNG_CMAP_GA_BACKGROUND;
|
| + output_processing = PNG_CMAP_GA;
|
| + }
|
| +
|
| + else
|
| + {
|
| + /* Either the input or the output has no alpha channel, so there
|
| + * will be no non-opaque pixels in the color-map; it will just be
|
| + * grayscale.
|
| + */
|
| + if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
| + png_error(png_ptr, "rgb[gray] color-map: too few entries");
|
| +
|
| + /* Ideally this code would use libpng to do the gamma correction,
|
| + * but if an input alpha channel is to be removed we will hit the
|
| + * libpng bug in gamma+compose+rgb-to-gray (the double gamma
|
| + * correction bug). Fix this by dropping the gamma correction in
|
| + * this case and doing it in the palette; this will result in
|
| + * duplicate palette entries, but that's better than the
|
| + * alternative of double gamma correction.
|
| + */
|
| + if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
| + png_ptr->num_trans > 0) &&
|
| + png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0)
|
| + {
|
| + cmap_entries = make_gray_file_colormap(display);
|
| + data_encoding = P_FILE;
|
| + }
|
| +
|
| + else
|
| + cmap_entries = make_gray_colormap(display);
|
| +
|
| + /* But if the input has alpha or transparency it must be removed
|
| + */
|
| + if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
| + png_ptr->num_trans > 0)
|
| + {
|
| + png_color_16 c;
|
| + png_uint_32 gray = back_g;
|
| +
|
| + /* We need to ensure that the application background exists in
|
| + * the colormap and that completely transparent pixels map to
|
| + * it. Achieve this simply by ensuring that the entry
|
| + * selected for the background really is the background color.
|
| + */
|
| + if (data_encoding == P_FILE) /* from the fixup above */
|
| + {
|
| + /* The app supplied a gray which is in output_encoding, we
|
| + * need to convert it to a value of the input (P_FILE)
|
| + * encoding then set this palette entry to the required
|
| + * output encoding.
|
| + */
|
| + if (output_encoding == P_sRGB)
|
| + gray = png_sRGB_table[gray]; /* now P_LINEAR */
|
| +
|
| + gray = PNG_DIV257(png_gamma_16bit_correct(gray,
|
| + png_ptr->colorspace.gamma)); /* now P_FILE */
|
| +
|
| + /* And make sure the corresponding palette entry contains
|
| + * exactly the required sRGB value.
|
| + */
|
| + png_create_colormap_entry(display, gray, back_g, back_g,
|
| + back_g, 0/*unused*/, output_encoding);
|
| + }
|
| +
|
| + else if (output_encoding == P_LINEAR)
|
| + {
|
| + gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
| +
|
| + /* And make sure the corresponding palette entry matches.
|
| + */
|
| + png_create_colormap_entry(display, gray, back_g, back_g,
|
| + back_g, 0/*unused*/, P_LINEAR);
|
| + }
|
| +
|
| + /* The background passed to libpng, however, must be the
|
| + * output (normally sRGB) value.
|
| + */
|
| + c.index = 0; /*unused*/
|
| + c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
| +
|
| + /* NOTE: the following is apparently a bug in libpng. Without
|
| + * it the transparent color recognition in
|
| + * png_set_background_fixed seems to go wrong.
|
| + */
|
| + expand_tRNS = 1;
|
| + png_set_background_fixed(png_ptr, &c,
|
| + PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
| + 0/*gamma: not used*/);
|
| + }
|
| +
|
| + output_processing = PNG_CMAP_NONE;
|
| + }
|
| + }
|
| +
|
| + else /* output is color */
|
| + {
|
| + /* We could use png_quantize here so long as there is no transparent
|
| + * color or alpha; png_quantize ignores alpha. Easier overall just
|
| + * to do it once and using PNG_DIV51 on the 6x6x6 reduced RGB cube.
|
| + * Consequently we always want libpng to produce sRGB data.
|
| + */
|
| + data_encoding = P_sRGB;
|
| +
|
| + /* Is there any transparency or alpha? */
|
| + if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
| + png_ptr->num_trans > 0)
|
| + {
|
| + /* Is there alpha in the output too? If so all four channels are
|
| + * processed into a special RGB cube with alpha support.
|
| + */
|
| + if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + {
|
| + png_uint_32 r;
|
| +
|
| + if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
|
| + png_error(png_ptr, "rgb+alpha color-map: too few entries");
|
| +
|
| + cmap_entries = make_rgb_colormap(display);
|
| +
|
| + /* Add a transparent entry. */
|
| + png_create_colormap_entry(display, cmap_entries, 255, 255,
|
| + 255, 0, P_sRGB);
|
| +
|
| + /* This is stored as the background index for the processing
|
| + * algorithm.
|
| + */
|
| + background_index = cmap_entries++;
|
| +
|
| + /* Add 27 r,g,b entries each with alpha 0.5. */
|
| + for (r=0; r<256; r = (r << 1) | 0x7f)
|
| + {
|
| + png_uint_32 g;
|
| +
|
| + for (g=0; g<256; g = (g << 1) | 0x7f)
|
| + {
|
| + png_uint_32 b;
|
| +
|
| + /* This generates components with the values 0, 127 and
|
| + * 255
|
| + */
|
| + for (b=0; b<256; b = (b << 1) | 0x7f)
|
| + png_create_colormap_entry(display, cmap_entries++,
|
| + r, g, b, 128, P_sRGB);
|
| + }
|
| + }
|
| +
|
| + expand_tRNS = 1;
|
| + output_processing = PNG_CMAP_RGB_ALPHA;
|
| + }
|
| +
|
| + else
|
| + {
|
| + /* Alpha/transparency must be removed. The background must
|
| + * exist in the color map (achieved by setting adding it after
|
| + * the 666 color-map). If the standard processing code will
|
| + * pick up this entry automatically that's all that is
|
| + * required; libpng can be called to do the background
|
| + * processing.
|
| + */
|
| + unsigned int sample_size =
|
| + PNG_IMAGE_SAMPLE_SIZE(output_format);
|
| + png_uint_32 r, g, b; /* sRGB background */
|
| +
|
| + if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
|
| + png_error(png_ptr, "rgb-alpha color-map: too few entries");
|
| +
|
| + cmap_entries = make_rgb_colormap(display);
|
| +
|
| + png_create_colormap_entry(display, cmap_entries, back_r,
|
| + back_g, back_b, 0/*unused*/, output_encoding);
|
| +
|
| + if (output_encoding == P_LINEAR)
|
| + {
|
| + r = PNG_sRGB_FROM_LINEAR(back_r * 255);
|
| + g = PNG_sRGB_FROM_LINEAR(back_g * 255);
|
| + b = PNG_sRGB_FROM_LINEAR(back_b * 255);
|
| + }
|
| +
|
| + else
|
| + {
|
| + r = back_r;
|
| + g = back_g;
|
| + b = back_g;
|
| + }
|
| +
|
| + /* Compare the newly-created color-map entry with the one the
|
| + * PNG_CMAP_RGB algorithm will use. If the two entries don't
|
| + * match, add the new one and set this as the background
|
| + * index.
|
| + */
|
| + if (memcmp((png_const_bytep)display->colormap +
|
| + sample_size * cmap_entries,
|
| + (png_const_bytep)display->colormap +
|
| + sample_size * PNG_RGB_INDEX(r,g,b),
|
| + sample_size) != 0)
|
| + {
|
| + /* The background color must be added. */
|
| + background_index = cmap_entries++;
|
| +
|
| + /* Add 27 r,g,b entries each with created by composing with
|
| + * the background at alpha 0.5.
|
| + */
|
| + for (r=0; r<256; r = (r << 1) | 0x7f)
|
| + {
|
| + for (g=0; g<256; g = (g << 1) | 0x7f)
|
| + {
|
| + /* This generates components with the values 0, 127
|
| + * and 255
|
| + */
|
| + for (b=0; b<256; b = (b << 1) | 0x7f)
|
| + png_create_colormap_entry(display, cmap_entries++,
|
| + png_colormap_compose(display, r, P_sRGB, 128,
|
| + back_r, output_encoding),
|
| + png_colormap_compose(display, g, P_sRGB, 128,
|
| + back_g, output_encoding),
|
| + png_colormap_compose(display, b, P_sRGB, 128,
|
| + back_b, output_encoding),
|
| + 0/*unused*/, output_encoding);
|
| + }
|
| + }
|
| +
|
| + expand_tRNS = 1;
|
| + output_processing = PNG_CMAP_RGB_ALPHA;
|
| + }
|
| +
|
| + else /* background color is in the standard color-map */
|
| + {
|
| + png_color_16 c;
|
| +
|
| + c.index = 0; /*unused*/
|
| + c.red = (png_uint_16)back_r;
|
| + c.gray = c.green = (png_uint_16)back_g;
|
| + c.blue = (png_uint_16)back_b;
|
| +
|
| + png_set_background_fixed(png_ptr, &c,
|
| + PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
| + 0/*gamma: not used*/);
|
| +
|
| + output_processing = PNG_CMAP_RGB;
|
| + }
|
| + }
|
| + }
|
| +
|
| + else /* no alpha or transparency in the input */
|
| + {
|
| + /* Alpha in the output is irrelevant, simply map the opaque input
|
| + * pixels to the 6x6x6 color-map.
|
| + */
|
| + if (PNG_RGB_COLORMAP_ENTRIES > image->colormap_entries)
|
| + png_error(png_ptr, "rgb color-map: too few entries");
|
| +
|
| + cmap_entries = make_rgb_colormap(display);
|
| + output_processing = PNG_CMAP_RGB;
|
| + }
|
| + }
|
| + break;
|
| +
|
| + case PNG_COLOR_TYPE_PALETTE:
|
| + /* It's already got a color-map. It may be necessary to eliminate the
|
| + * tRNS entries though.
|
| + */
|
| + {
|
| + unsigned int num_trans = png_ptr->num_trans;
|
| + png_const_bytep trans = num_trans > 0 ? png_ptr->trans_alpha : NULL;
|
| + png_const_colorp colormap = png_ptr->palette;
|
| + const int do_background = trans != NULL &&
|
| + (output_format & PNG_FORMAT_FLAG_ALPHA) == 0;
|
| + unsigned int i;
|
| +
|
| + /* Just in case: */
|
| + if (trans == NULL)
|
| + num_trans = 0;
|
| +
|
| + output_processing = PNG_CMAP_NONE;
|
| + data_encoding = P_FILE; /* Don't change from color-map indices */
|
| + cmap_entries = png_ptr->num_palette;
|
| + if (cmap_entries > 256)
|
| + cmap_entries = 256;
|
| +
|
| + if (cmap_entries > image->colormap_entries)
|
| + png_error(png_ptr, "palette color-map: too few entries");
|
| +
|
| + for (i=0; i < cmap_entries; ++i)
|
| + {
|
| + if (do_background != 0 && i < num_trans && trans[i] < 255)
|
| + {
|
| + if (trans[i] == 0)
|
| + png_create_colormap_entry(display, i, back_r, back_g,
|
| + back_b, 0, output_encoding);
|
| +
|
| + else
|
| + {
|
| + /* Must compose the PNG file color in the color-map entry
|
| + * on the sRGB color in 'back'.
|
| + */
|
| + png_create_colormap_entry(display, i,
|
| + png_colormap_compose(display, colormap[i].red, P_FILE,
|
| + trans[i], back_r, output_encoding),
|
| + png_colormap_compose(display, colormap[i].green, P_FILE,
|
| + trans[i], back_g, output_encoding),
|
| + png_colormap_compose(display, colormap[i].blue, P_FILE,
|
| + trans[i], back_b, output_encoding),
|
| + output_encoding == P_LINEAR ? trans[i] * 257U :
|
| + trans[i],
|
| + output_encoding);
|
| + }
|
| + }
|
| +
|
| + else
|
| + png_create_colormap_entry(display, i, colormap[i].red,
|
| + colormap[i].green, colormap[i].blue,
|
| + i < num_trans ? trans[i] : 255U, P_FILE/*8-bit*/);
|
| + }
|
| +
|
| + /* The PNG data may have indices packed in fewer than 8 bits, it
|
| + * must be expanded if so.
|
| + */
|
| + if (png_ptr->bit_depth < 8)
|
| + png_set_packing(png_ptr);
|
| + }
|
| + break;
|
| +
|
| + default:
|
| + png_error(png_ptr, "invalid PNG color type");
|
| + /*NOT REACHED*/
|
| + }
|
| +
|
| + /* Now deal with the output processing */
|
| + if (expand_tRNS != 0 && png_ptr->num_trans > 0 &&
|
| + (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
|
| + png_set_tRNS_to_alpha(png_ptr);
|
| +
|
| + switch (data_encoding)
|
| + {
|
| + case P_sRGB:
|
| + /* Change to 8-bit sRGB */
|
| + png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, PNG_GAMMA_sRGB);
|
| + /* FALL THROUGH */
|
| +
|
| + case P_FILE:
|
| + if (png_ptr->bit_depth > 8)
|
| + png_set_scale_16(png_ptr);
|
| + break;
|
| +
|
| +#ifdef __GNUC__
|
| + default:
|
| + png_error(png_ptr, "bad data option (internal error)");
|
| +#endif
|
| + }
|
| +
|
| + if (cmap_entries > 256 || cmap_entries > image->colormap_entries)
|
| + png_error(png_ptr, "color map overflow (BAD internal error)");
|
| +
|
| + image->colormap_entries = cmap_entries;
|
| +
|
| + /* Double check using the recorded background index */
|
| + switch (output_processing)
|
| + {
|
| + case PNG_CMAP_NONE:
|
| + if (background_index != PNG_CMAP_NONE_BACKGROUND)
|
| + goto bad_background;
|
| + break;
|
| +
|
| + case PNG_CMAP_GA:
|
| + if (background_index != PNG_CMAP_GA_BACKGROUND)
|
| + goto bad_background;
|
| + break;
|
| +
|
| + case PNG_CMAP_TRANS:
|
| + if (background_index >= cmap_entries ||
|
| + background_index != PNG_CMAP_TRANS_BACKGROUND)
|
| + goto bad_background;
|
| + break;
|
| +
|
| + case PNG_CMAP_RGB:
|
| + if (background_index != PNG_CMAP_RGB_BACKGROUND)
|
| + goto bad_background;
|
| + break;
|
| +
|
| + case PNG_CMAP_RGB_ALPHA:
|
| + if (background_index != PNG_CMAP_RGB_ALPHA_BACKGROUND)
|
| + goto bad_background;
|
| + break;
|
| +
|
| + default:
|
| + png_error(png_ptr, "bad processing option (internal error)");
|
| +
|
| + bad_background:
|
| + png_error(png_ptr, "bad background index (internal error)");
|
| + }
|
| +
|
| + display->colormap_processing = output_processing;
|
| +
|
| + return 1/*ok*/;
|
| +}
|
| +
|
| +/* The final part of the color-map read called from png_image_finish_read. */
|
| +static int
|
| +png_image_read_and_map(png_voidp argument)
|
| +{
|
| + png_image_read_control *display = png_voidcast(png_image_read_control*,
|
| + argument);
|
| + png_imagep image = display->image;
|
| + png_structrp png_ptr = image->opaque->png_ptr;
|
| + int passes;
|
| +
|
| + /* Called when the libpng data must be transformed into the color-mapped
|
| + * form. There is a local row buffer in display->local and this routine must
|
| + * do the interlace handling.
|
| + */
|
| + switch (png_ptr->interlaced)
|
| + {
|
| + case PNG_INTERLACE_NONE:
|
| + passes = 1;
|
| + break;
|
| +
|
| + case PNG_INTERLACE_ADAM7:
|
| + passes = PNG_INTERLACE_ADAM7_PASSES;
|
| + break;
|
| +
|
| + default:
|
| + png_error(png_ptr, "unknown interlace type");
|
| + }
|
| +
|
| + {
|
| + png_uint_32 height = image->height;
|
| + png_uint_32 width = image->width;
|
| + int proc = display->colormap_processing;
|
| + png_bytep first_row = png_voidcast(png_bytep, display->first_row);
|
| + ptrdiff_t step_row = display->row_bytes;
|
| + int pass;
|
| +
|
| + for (pass = 0; pass < passes; ++pass)
|
| + {
|
| + unsigned int startx, stepx, stepy;
|
| + png_uint_32 y;
|
| +
|
| + if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
| + {
|
| + /* The row may be empty for a short image: */
|
| + if (PNG_PASS_COLS(width, pass) == 0)
|
| + continue;
|
| +
|
| + startx = PNG_PASS_START_COL(pass);
|
| + stepx = PNG_PASS_COL_OFFSET(pass);
|
| + y = PNG_PASS_START_ROW(pass);
|
| + stepy = PNG_PASS_ROW_OFFSET(pass);
|
| + }
|
| +
|
| + else
|
| + {
|
| + y = 0;
|
| + startx = 0;
|
| + stepx = stepy = 1;
|
| + }
|
| +
|
| + for (; y<height; y += stepy)
|
| + {
|
| + png_bytep inrow = png_voidcast(png_bytep, display->local_row);
|
| + png_bytep outrow = first_row + y * step_row;
|
| + png_const_bytep end_row = outrow + width;
|
| +
|
| + /* Read read the libpng data into the temporary buffer. */
|
| + png_read_row(png_ptr, inrow, NULL);
|
| +
|
| + /* Now process the row according to the processing option, note
|
| + * that the caller verifies that the format of the libpng output
|
| + * data is as required.
|
| + */
|
| + outrow += startx;
|
| + switch (proc)
|
| + {
|
| + case PNG_CMAP_GA:
|
| + for (; outrow < end_row; outrow += stepx)
|
| + {
|
| + /* The data is always in the PNG order */
|
| + unsigned int gray = *inrow++;
|
| + unsigned int alpha = *inrow++;
|
| + unsigned int entry;
|
| +
|
| + /* NOTE: this code is copied as a comment in
|
| + * make_ga_colormap above. Please update the
|
| + * comment if you change this code!
|
| + */
|
| + if (alpha > 229) /* opaque */
|
| + {
|
| + entry = (231 * gray + 128) >> 8;
|
| + }
|
| + else if (alpha < 26) /* transparent */
|
| + {
|
| + entry = 231;
|
| + }
|
| + else /* partially opaque */
|
| + {
|
| + entry = 226 + 6 * PNG_DIV51(alpha) + PNG_DIV51(gray);
|
| + }
|
| +
|
| + *outrow = (png_byte)entry;
|
| + }
|
| + break;
|
| +
|
| + case PNG_CMAP_TRANS:
|
| + for (; outrow < end_row; outrow += stepx)
|
| + {
|
| + png_byte gray = *inrow++;
|
| + png_byte alpha = *inrow++;
|
| +
|
| + if (alpha == 0)
|
| + *outrow = PNG_CMAP_TRANS_BACKGROUND;
|
| +
|
| + else if (gray != PNG_CMAP_TRANS_BACKGROUND)
|
| + *outrow = gray;
|
| +
|
| + else
|
| + *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1);
|
| + }
|
| + break;
|
| +
|
| + case PNG_CMAP_RGB:
|
| + for (; outrow < end_row; outrow += stepx)
|
| + {
|
| + *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], inrow[2]);
|
| + inrow += 3;
|
| + }
|
| + break;
|
| +
|
| + case PNG_CMAP_RGB_ALPHA:
|
| + for (; outrow < end_row; outrow += stepx)
|
| + {
|
| + unsigned int alpha = inrow[3];
|
| +
|
| + /* Because the alpha entries only hold alpha==0.5 values
|
| + * split the processing at alpha==0.25 (64) and 0.75
|
| + * (196).
|
| + */
|
| +
|
| + if (alpha >= 196)
|
| + *outrow = PNG_RGB_INDEX(inrow[0], inrow[1],
|
| + inrow[2]);
|
| +
|
| + else if (alpha < 64)
|
| + *outrow = PNG_CMAP_RGB_ALPHA_BACKGROUND;
|
| +
|
| + else
|
| + {
|
| + /* Likewise there are three entries for each of r, g
|
| + * and b. We could select the entry by popcount on
|
| + * the top two bits on those architectures that
|
| + * support it, this is what the code below does,
|
| + * crudely.
|
| + */
|
| + unsigned int back_i = PNG_CMAP_RGB_ALPHA_BACKGROUND+1;
|
| +
|
| + /* Here are how the values map:
|
| + *
|
| + * 0x00 .. 0x3f -> 0
|
| + * 0x40 .. 0xbf -> 1
|
| + * 0xc0 .. 0xff -> 2
|
| + *
|
| + * So, as above with the explicit alpha checks, the
|
| + * breakpoints are at 64 and 196.
|
| + */
|
| + if (inrow[0] & 0x80) back_i += 9; /* red */
|
| + if (inrow[0] & 0x40) back_i += 9;
|
| + if (inrow[0] & 0x80) back_i += 3; /* green */
|
| + if (inrow[0] & 0x40) back_i += 3;
|
| + if (inrow[0] & 0x80) back_i += 1; /* blue */
|
| + if (inrow[0] & 0x40) back_i += 1;
|
| +
|
| + *outrow = (png_byte)back_i;
|
| + }
|
| +
|
| + inrow += 4;
|
| + }
|
| + break;
|
| +
|
| + default:
|
| + break;
|
| + }
|
| + }
|
| + }
|
| + }
|
| +
|
| + return 1;
|
| +}
|
| +
|
| +static int
|
| +png_image_read_colormapped(png_voidp argument)
|
| +{
|
| + png_image_read_control *display = png_voidcast(png_image_read_control*,
|
| + argument);
|
| + png_imagep image = display->image;
|
| + png_controlp control = image->opaque;
|
| + png_structrp png_ptr = control->png_ptr;
|
| + png_inforp info_ptr = control->info_ptr;
|
| +
|
| + int passes = 0; /* As a flag */
|
| +
|
| + PNG_SKIP_CHUNKS(png_ptr);
|
| +
|
| + /* Update the 'info' structure and make sure the result is as required; first
|
| + * make sure to turn on the interlace handling if it will be required
|
| + * (because it can't be turned on *after* the call to png_read_update_info!)
|
| + */
|
| + if (display->colormap_processing == PNG_CMAP_NONE)
|
| + passes = png_set_interlace_handling(png_ptr);
|
| +
|
| + png_read_update_info(png_ptr, info_ptr);
|
| +
|
| + /* The expected output can be deduced from the colormap_processing option. */
|
| + switch (display->colormap_processing)
|
| + {
|
| + case PNG_CMAP_NONE:
|
| + /* Output must be one channel and one byte per pixel, the output
|
| + * encoding can be anything.
|
| + */
|
| + if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
|
| + info_ptr->color_type == PNG_COLOR_TYPE_GRAY) &&
|
| + info_ptr->bit_depth == 8)
|
| + break;
|
| +
|
| + goto bad_output;
|
| +
|
| + case PNG_CMAP_TRANS:
|
| + case PNG_CMAP_GA:
|
| + /* Output must be two channels and the 'G' one must be sRGB, the latter
|
| + * can be checked with an exact number because it should have been set
|
| + * to this number above!
|
| + */
|
| + if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
|
| + info_ptr->bit_depth == 8 &&
|
| + png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
| + image->colormap_entries == 256)
|
| + break;
|
| +
|
| + goto bad_output;
|
| +
|
| + case PNG_CMAP_RGB:
|
| + /* Output must be 8-bit sRGB encoded RGB */
|
| + if (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
|
| + info_ptr->bit_depth == 8 &&
|
| + png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
| + image->colormap_entries == 216)
|
| + break;
|
| +
|
| + goto bad_output;
|
| +
|
| + case PNG_CMAP_RGB_ALPHA:
|
| + /* Output must be 8-bit sRGB encoded RGBA */
|
| + if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
|
| + info_ptr->bit_depth == 8 &&
|
| + png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
| + image->colormap_entries == 244 /* 216 + 1 + 27 */)
|
| + break;
|
| +
|
| + /* goto bad_output; */
|
| + /* FALL THROUGH */
|
| +
|
| + default:
|
| + bad_output:
|
| + png_error(png_ptr, "bad color-map processing (internal error)");
|
| + }
|
| +
|
| + /* Now read the rows. Do this here if it is possible to read directly into
|
| + * the output buffer, otherwise allocate a local row buffer of the maximum
|
| + * size libpng requires and call the relevant processing routine safely.
|
| + */
|
| + {
|
| + png_voidp first_row = display->buffer;
|
| + ptrdiff_t row_bytes = display->row_stride;
|
| +
|
| + /* The following expression is designed to work correctly whether it gives
|
| + * a signed or an unsigned result.
|
| + */
|
| + if (row_bytes < 0)
|
| + {
|
| + char *ptr = png_voidcast(char*, first_row);
|
| + ptr += (image->height-1) * (-row_bytes);
|
| + first_row = png_voidcast(png_voidp, ptr);
|
| + }
|
| +
|
| + display->first_row = first_row;
|
| + display->row_bytes = row_bytes;
|
| + }
|
| +
|
| + if (passes == 0)
|
| + {
|
| + int result;
|
| + png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
| +
|
| + display->local_row = row;
|
| + result = png_safe_execute(image, png_image_read_and_map, display);
|
| + display->local_row = NULL;
|
| + png_free(png_ptr, row);
|
| +
|
| + return result;
|
| + }
|
| +
|
| + else
|
| + {
|
| + png_alloc_size_t row_bytes = display->row_bytes;
|
| +
|
| + while (--passes >= 0)
|
| + {
|
| + png_uint_32 y = image->height;
|
| + png_bytep row = png_voidcast(png_bytep, display->first_row);
|
| +
|
| + while (y-- > 0)
|
| + {
|
| + png_read_row(png_ptr, row, NULL);
|
| + row += row_bytes;
|
| + }
|
| + }
|
| +
|
| + return 1;
|
| + }
|
| +}
|
| +
|
| +/* Just the row reading part of png_image_read. */
|
| +static int
|
| +png_image_read_composite(png_voidp argument)
|
| +{
|
| + png_image_read_control *display = png_voidcast(png_image_read_control*,
|
| + argument);
|
| + png_imagep image = display->image;
|
| + png_structrp png_ptr = image->opaque->png_ptr;
|
| + int passes;
|
| +
|
| + switch (png_ptr->interlaced)
|
| + {
|
| + case PNG_INTERLACE_NONE:
|
| + passes = 1;
|
| + break;
|
| +
|
| + case PNG_INTERLACE_ADAM7:
|
| + passes = PNG_INTERLACE_ADAM7_PASSES;
|
| + break;
|
| +
|
| + default:
|
| + png_error(png_ptr, "unknown interlace type");
|
| + }
|
| +
|
| + {
|
| + png_uint_32 height = image->height;
|
| + png_uint_32 width = image->width;
|
| + ptrdiff_t step_row = display->row_bytes;
|
| + unsigned int channels =
|
| + (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
|
| + int pass;
|
| +
|
| + for (pass = 0; pass < passes; ++pass)
|
| + {
|
| + unsigned int startx, stepx, stepy;
|
| + png_uint_32 y;
|
| +
|
| + if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
| + {
|
| + /* The row may be empty for a short image: */
|
| + if (PNG_PASS_COLS(width, pass) == 0)
|
| + continue;
|
| +
|
| + startx = PNG_PASS_START_COL(pass) * channels;
|
| + stepx = PNG_PASS_COL_OFFSET(pass) * channels;
|
| + y = PNG_PASS_START_ROW(pass);
|
| + stepy = PNG_PASS_ROW_OFFSET(pass);
|
| + }
|
| +
|
| + else
|
| + {
|
| + y = 0;
|
| + startx = 0;
|
| + stepx = channels;
|
| + stepy = 1;
|
| + }
|
| +
|
| + for (; y<height; y += stepy)
|
| + {
|
| + png_bytep inrow = png_voidcast(png_bytep, display->local_row);
|
| + png_bytep outrow;
|
| + png_const_bytep end_row;
|
| +
|
| + /* Read the row, which is packed: */
|
| + png_read_row(png_ptr, inrow, NULL);
|
| +
|
| + outrow = png_voidcast(png_bytep, display->first_row);
|
| + outrow += y * step_row;
|
| + end_row = outrow + width * channels;
|
| +
|
| + /* Now do the composition on each pixel in this row. */
|
| + outrow += startx;
|
| + for (; outrow < end_row; outrow += stepx)
|
| + {
|
| + png_byte alpha = inrow[channels];
|
| +
|
| + if (alpha > 0) /* else no change to the output */
|
| + {
|
| + unsigned int c;
|
| +
|
| + for (c=0; c<channels; ++c)
|
| + {
|
| + png_uint_32 component = inrow[c];
|
| +
|
| + if (alpha < 255) /* else just use component */
|
| + {
|
| + /* This is PNG_OPTIMIZED_ALPHA, the component value
|
| + * is a linear 8-bit value. Combine this with the
|
| + * current outrow[c] value which is sRGB encoded.
|
| + * Arithmetic here is 16-bits to preserve the output
|
| + * values correctly.
|
| + */
|
| + component *= 257*255; /* =65535 */
|
| + component += (255-alpha)*png_sRGB_table[outrow[c]];
|
| +
|
| + /* So 'component' is scaled by 255*65535 and is
|
| + * therefore appropriate for the sRGB to linear
|
| + * conversion table.
|
| + */
|
| + component = PNG_sRGB_FROM_LINEAR(component);
|
| + }
|
| +
|
| + outrow[c] = (png_byte)component;
|
| + }
|
| + }
|
| +
|
| + inrow += channels+1; /* components and alpha channel */
|
| + }
|
| + }
|
| + }
|
| + }
|
| +
|
| + return 1;
|
| +}
|
| +
|
| +/* The do_local_background case; called when all the following transforms are to
|
| + * be done:
|
| + *
|
| + * PNG_RGB_TO_GRAY
|
| + * PNG_COMPOSITE
|
| + * PNG_GAMMA
|
| + *
|
| + * This is a work-around for the fact that both the PNG_RGB_TO_GRAY and
|
| + * PNG_COMPOSITE code performs gamma correction, so we get double gamma
|
| + * correction. The fix-up is to prevent the PNG_COMPOSITE operation from
|
| + * happening inside libpng, so this routine sees an 8 or 16-bit gray+alpha
|
| + * row and handles the removal or pre-multiplication of the alpha channel.
|
| + */
|
| +static int
|
| +png_image_read_background(png_voidp argument)
|
| +{
|
| + png_image_read_control *display = png_voidcast(png_image_read_control*,
|
| + argument);
|
| + png_imagep image = display->image;
|
| + png_structrp png_ptr = image->opaque->png_ptr;
|
| + png_inforp info_ptr = image->opaque->info_ptr;
|
| + png_uint_32 height = image->height;
|
| + png_uint_32 width = image->width;
|
| + int pass, passes;
|
| +
|
| + /* Double check the convoluted logic below. We expect to get here with
|
| + * libpng doing rgb to gray and gamma correction but background processing
|
| + * left to the png_image_read_background function. The rows libpng produce
|
| + * might be 8 or 16-bit but should always have two channels; gray plus alpha.
|
| + */
|
| + if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
|
| + png_error(png_ptr, "lost rgb to gray");
|
| +
|
| + if ((png_ptr->transformations & PNG_COMPOSE) != 0)
|
| + png_error(png_ptr, "unexpected compose");
|
| +
|
| + if (png_get_channels(png_ptr, info_ptr) != 2)
|
| + png_error(png_ptr, "lost/gained channels");
|
| +
|
| + /* Expect the 8-bit case to always remove the alpha channel */
|
| + if ((image->format & PNG_FORMAT_FLAG_LINEAR) == 0 &&
|
| + (image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + png_error(png_ptr, "unexpected 8-bit transformation");
|
| +
|
| + switch (png_ptr->interlaced)
|
| + {
|
| + case PNG_INTERLACE_NONE:
|
| + passes = 1;
|
| + break;
|
| +
|
| + case PNG_INTERLACE_ADAM7:
|
| + passes = PNG_INTERLACE_ADAM7_PASSES;
|
| + break;
|
| +
|
| + default:
|
| + png_error(png_ptr, "unknown interlace type");
|
| + }
|
| +
|
| + /* Use direct access to info_ptr here because otherwise the simplified API
|
| + * would require PNG_EASY_ACCESS_SUPPORTED (just for this.) Note this is
|
| + * checking the value after libpng expansions, not the original value in the
|
| + * PNG.
|
| + */
|
| + switch (info_ptr->bit_depth)
|
| + {
|
| + case 8:
|
| + /* 8-bit sRGB gray values with an alpha channel; the alpha channel is
|
| + * to be removed by composing on a background: either the row if
|
| + * display->background is NULL or display->background->green if not.
|
| + * Unlike the code above ALPHA_OPTIMIZED has *not* been done.
|
| + */
|
| + {
|
| + png_bytep first_row = png_voidcast(png_bytep, display->first_row);
|
| + ptrdiff_t step_row = display->row_bytes;
|
| +
|
| + for (pass = 0; pass < passes; ++pass)
|
| + {
|
| + png_bytep row = png_voidcast(png_bytep,
|
| + display->first_row);
|
| + unsigned int startx, stepx, stepy;
|
| + png_uint_32 y;
|
| +
|
| + if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
| + {
|
| + /* The row may be empty for a short image: */
|
| + if (PNG_PASS_COLS(width, pass) == 0)
|
| + continue;
|
| +
|
| + startx = PNG_PASS_START_COL(pass);
|
| + stepx = PNG_PASS_COL_OFFSET(pass);
|
| + y = PNG_PASS_START_ROW(pass);
|
| + stepy = PNG_PASS_ROW_OFFSET(pass);
|
| + }
|
| +
|
| + else
|
| + {
|
| + y = 0;
|
| + startx = 0;
|
| + stepx = stepy = 1;
|
| + }
|
| +
|
| + if (display->background == NULL)
|
| + {
|
| + for (; y<height; y += stepy)
|
| + {
|
| + png_bytep inrow = png_voidcast(png_bytep,
|
| + display->local_row);
|
| + png_bytep outrow = first_row + y * step_row;
|
| + png_const_bytep end_row = outrow + width;
|
| +
|
| + /* Read the row, which is packed: */
|
| + png_read_row(png_ptr, inrow, NULL);
|
| +
|
| + /* Now do the composition on each pixel in this row. */
|
| + outrow += startx;
|
| + for (; outrow < end_row; outrow += stepx)
|
| + {
|
| + png_byte alpha = inrow[1];
|
| +
|
| + if (alpha > 0) /* else no change to the output */
|
| + {
|
| + png_uint_32 component = inrow[0];
|
| +
|
| + if (alpha < 255) /* else just use component */
|
| + {
|
| + /* Since PNG_OPTIMIZED_ALPHA was not set it is
|
| + * necessary to invert the sRGB transfer
|
| + * function and multiply the alpha out.
|
| + */
|
| + component = png_sRGB_table[component] * alpha;
|
| + component += png_sRGB_table[outrow[0]] *
|
| + (255-alpha);
|
| + component = PNG_sRGB_FROM_LINEAR(component);
|
| + }
|
| +
|
| + outrow[0] = (png_byte)component;
|
| + }
|
| +
|
| + inrow += 2; /* gray and alpha channel */
|
| + }
|
| + }
|
| + }
|
| +
|
| + else /* constant background value */
|
| + {
|
| + png_byte background8 = display->background->green;
|
| + png_uint_16 background = png_sRGB_table[background8];
|
| +
|
| + for (; y<height; y += stepy)
|
| + {
|
| + png_bytep inrow = png_voidcast(png_bytep,
|
| + display->local_row);
|
| + png_bytep outrow = first_row + y * step_row;
|
| + png_const_bytep end_row = outrow + width;
|
| +
|
| + /* Read the row, which is packed: */
|
| + png_read_row(png_ptr, inrow, NULL);
|
| +
|
| + /* Now do the composition on each pixel in this row. */
|
| + outrow += startx;
|
| + for (; outrow < end_row; outrow += stepx)
|
| + {
|
| + png_byte alpha = inrow[1];
|
| +
|
| + if (alpha > 0) /* else use background */
|
| + {
|
| + png_uint_32 component = inrow[0];
|
| +
|
| + if (alpha < 255) /* else just use component */
|
| + {
|
| + component = png_sRGB_table[component] * alpha;
|
| + component += background * (255-alpha);
|
| + component = PNG_sRGB_FROM_LINEAR(component);
|
| + }
|
| +
|
| + outrow[0] = (png_byte)component;
|
| + }
|
| +
|
| + else
|
| + outrow[0] = background8;
|
| +
|
| + inrow += 2; /* gray and alpha channel */
|
| + }
|
| +
|
| + row += display->row_bytes;
|
| + }
|
| + }
|
| + }
|
| + }
|
| + break;
|
| +
|
| + case 16:
|
| + /* 16-bit linear with pre-multiplied alpha; the pre-multiplication must
|
| + * still be done and, maybe, the alpha channel removed. This code also
|
| + * handles the alpha-first option.
|
| + */
|
| + {
|
| + png_uint_16p first_row = png_voidcast(png_uint_16p,
|
| + display->first_row);
|
| + /* The division by two is safe because the caller passed in a
|
| + * stride which was multiplied by 2 (below) to get row_bytes.
|
| + */
|
| + ptrdiff_t step_row = display->row_bytes / 2;
|
| + int preserve_alpha = (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
|
| + unsigned int outchannels = 1+preserve_alpha;
|
| + int swap_alpha = 0;
|
| +
|
| +# ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
|
| + if (preserve_alpha != 0 &&
|
| + (image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
|
| + swap_alpha = 1;
|
| +# endif
|
| +
|
| + for (pass = 0; pass < passes; ++pass)
|
| + {
|
| + unsigned int startx, stepx, stepy;
|
| + png_uint_32 y;
|
| +
|
| + /* The 'x' start and step are adjusted to output components here.
|
| + */
|
| + if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
| + {
|
| + /* The row may be empty for a short image: */
|
| + if (PNG_PASS_COLS(width, pass) == 0)
|
| + continue;
|
| +
|
| + startx = PNG_PASS_START_COL(pass) * outchannels;
|
| + stepx = PNG_PASS_COL_OFFSET(pass) * outchannels;
|
| + y = PNG_PASS_START_ROW(pass);
|
| + stepy = PNG_PASS_ROW_OFFSET(pass);
|
| + }
|
| +
|
| + else
|
| + {
|
| + y = 0;
|
| + startx = 0;
|
| + stepx = outchannels;
|
| + stepy = 1;
|
| + }
|
| +
|
| + for (; y<height; y += stepy)
|
| + {
|
| + png_const_uint_16p inrow;
|
| + png_uint_16p outrow = first_row + y*step_row;
|
| + png_uint_16p end_row = outrow + width * outchannels;
|
| +
|
| + /* Read the row, which is packed: */
|
| + png_read_row(png_ptr, png_voidcast(png_bytep,
|
| + display->local_row), NULL);
|
| + inrow = png_voidcast(png_const_uint_16p, display->local_row);
|
| +
|
| + /* Now do the pre-multiplication on each pixel in this row.
|
| + */
|
| + outrow += startx;
|
| + for (; outrow < end_row; outrow += stepx)
|
| + {
|
| + png_uint_32 component = inrow[0];
|
| + png_uint_16 alpha = inrow[1];
|
| +
|
| + if (alpha > 0) /* else 0 */
|
| + {
|
| + if (alpha < 65535) /* else just use component */
|
| + {
|
| + component *= alpha;
|
| + component += 32767;
|
| + component /= 65535;
|
| + }
|
| + }
|
| +
|
| + else
|
| + component = 0;
|
| +
|
| + outrow[swap_alpha] = (png_uint_16)component;
|
| + if (preserve_alpha != 0)
|
| + outrow[1 ^ swap_alpha] = alpha;
|
| +
|
| + inrow += 2; /* components and alpha channel */
|
| + }
|
| + }
|
| + }
|
| + }
|
| + break;
|
| +
|
| +#ifdef __GNUC__
|
| + default:
|
| + png_error(png_ptr, "unexpected bit depth");
|
| +#endif
|
| + }
|
| +
|
| + return 1;
|
| +}
|
| +
|
| +/* The guts of png_image_finish_read as a png_safe_execute callback. */
|
| +static int
|
| +png_image_read_direct(png_voidp argument)
|
| +{
|
| + png_image_read_control *display = png_voidcast(png_image_read_control*,
|
| + argument);
|
| + png_imagep image = display->image;
|
| + png_structrp png_ptr = image->opaque->png_ptr;
|
| + png_inforp info_ptr = image->opaque->info_ptr;
|
| +
|
| + png_uint_32 format = image->format;
|
| + int linear = (format & PNG_FORMAT_FLAG_LINEAR) != 0;
|
| + int do_local_compose = 0;
|
| + int do_local_background = 0; /* to avoid double gamma correction bug */
|
| + int passes = 0;
|
| +
|
| + /* Add transforms to ensure the correct output format is produced then check
|
| + * that the required implementation support is there. Always expand; always
|
| + * need 8 bits minimum, no palette and expanded tRNS.
|
| + */
|
| + png_set_expand(png_ptr);
|
| +
|
| + /* Now check the format to see if it was modified. */
|
| + {
|
| + png_uint_32 base_format = png_image_format(png_ptr) &
|
| + ~PNG_FORMAT_FLAG_COLORMAP /* removed by png_set_expand */;
|
| + png_uint_32 change = format ^ base_format;
|
| + png_fixed_point output_gamma;
|
| + int mode; /* alpha mode */
|
| +
|
| + /* Do this first so that we have a record if rgb to gray is happening. */
|
| + if ((change & PNG_FORMAT_FLAG_COLOR) != 0)
|
| + {
|
| + /* gray<->color transformation required. */
|
| + if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
|
| + png_set_gray_to_rgb(png_ptr);
|
| +
|
| + else
|
| + {
|
| + /* libpng can't do both rgb to gray and
|
| + * background/pre-multiplication if there is also significant gamma
|
| + * correction, because both operations require linear colors and
|
| + * the code only supports one transform doing the gamma correction.
|
| + * Handle this by doing the pre-multiplication or background
|
| + * operation in this code, if necessary.
|
| + *
|
| + * TODO: fix this by rewriting pngrtran.c (!)
|
| + *
|
| + * For the moment (given that fixing this in pngrtran.c is an
|
| + * enormous change) 'do_local_background' is used to indicate that
|
| + * the problem exists.
|
| + */
|
| + if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + do_local_background = 1/*maybe*/;
|
| +
|
| + png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE,
|
| + PNG_RGB_TO_GRAY_DEFAULT, PNG_RGB_TO_GRAY_DEFAULT);
|
| + }
|
| +
|
| + change &= ~PNG_FORMAT_FLAG_COLOR;
|
| + }
|
| +
|
| + /* Set the gamma appropriately, linear for 16-bit input, sRGB otherwise.
|
| + */
|
| + {
|
| + png_fixed_point input_gamma_default;
|
| +
|
| + if ((base_format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
|
| + (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
|
| + input_gamma_default = PNG_GAMMA_LINEAR;
|
| + else
|
| + input_gamma_default = PNG_DEFAULT_sRGB;
|
| +
|
| + /* Call png_set_alpha_mode to set the default for the input gamma; the
|
| + * output gamma is set by a second call below.
|
| + */
|
| + png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, input_gamma_default);
|
| + }
|
| +
|
| + if (linear != 0)
|
| + {
|
| + /* If there *is* an alpha channel in the input it must be multiplied
|
| + * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG.
|
| + */
|
| + if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + mode = PNG_ALPHA_STANDARD; /* associated alpha */
|
| +
|
| + else
|
| + mode = PNG_ALPHA_PNG;
|
| +
|
| + output_gamma = PNG_GAMMA_LINEAR;
|
| + }
|
| +
|
| + else
|
| + {
|
| + mode = PNG_ALPHA_PNG;
|
| + output_gamma = PNG_DEFAULT_sRGB;
|
| + }
|
| +
|
| + /* If 'do_local_background' is set check for the presence of gamma
|
| + * correction; this is part of the work-round for the libpng bug
|
| + * described above.
|
| + *
|
| + * TODO: fix libpng and remove this.
|
| + */
|
| + if (do_local_background != 0)
|
| + {
|
| + png_fixed_point gtest;
|
| +
|
| + /* This is 'png_gamma_threshold' from pngrtran.c; the test used for
|
| + * gamma correction, the screen gamma hasn't been set on png_struct
|
| + * yet; it's set below. png_struct::gamma, however, is set to the
|
| + * final value.
|
| + */
|
| + if (png_muldiv(>est, output_gamma, png_ptr->colorspace.gamma,
|
| + PNG_FP_1) != 0 && png_gamma_significant(gtest) == 0)
|
| + do_local_background = 0;
|
| +
|
| + else if (mode == PNG_ALPHA_STANDARD)
|
| + {
|
| + do_local_background = 2/*required*/;
|
| + mode = PNG_ALPHA_PNG; /* prevent libpng doing it */
|
| + }
|
| +
|
| + /* else leave as 1 for the checks below */
|
| + }
|
| +
|
| + /* If the bit-depth changes then handle that here. */
|
| + if ((change & PNG_FORMAT_FLAG_LINEAR) != 0)
|
| + {
|
| + if (linear != 0 /*16-bit output*/)
|
| + png_set_expand_16(png_ptr);
|
| +
|
| + else /* 8-bit output */
|
| + png_set_scale_16(png_ptr);
|
| +
|
| + change &= ~PNG_FORMAT_FLAG_LINEAR;
|
| + }
|
| +
|
| + /* Now the background/alpha channel changes. */
|
| + if ((change & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + {
|
| + /* Removing an alpha channel requires composition for the 8-bit
|
| + * formats; for the 16-bit it is already done, above, by the
|
| + * pre-multiplication and the channel just needs to be stripped.
|
| + */
|
| + if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + {
|
| + /* If RGB->gray is happening the alpha channel must be left and the
|
| + * operation completed locally.
|
| + *
|
| + * TODO: fix libpng and remove this.
|
| + */
|
| + if (do_local_background != 0)
|
| + do_local_background = 2/*required*/;
|
| +
|
| + /* 16-bit output: just remove the channel */
|
| + else if (linear != 0) /* compose on black (well, pre-multiply) */
|
| + png_set_strip_alpha(png_ptr);
|
| +
|
| + /* 8-bit output: do an appropriate compose */
|
| + else if (display->background != NULL)
|
| + {
|
| + png_color_16 c;
|
| +
|
| + c.index = 0; /*unused*/
|
| + c.red = display->background->red;
|
| + c.green = display->background->green;
|
| + c.blue = display->background->blue;
|
| + c.gray = display->background->green;
|
| +
|
| + /* This is always an 8-bit sRGB value, using the 'green' channel
|
| + * for gray is much better than calculating the luminance here;
|
| + * we can get off-by-one errors in that calculation relative to
|
| + * the app expectations and that will show up in transparent
|
| + * pixels.
|
| + */
|
| + png_set_background_fixed(png_ptr, &c,
|
| + PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
| + 0/*gamma: not used*/);
|
| + }
|
| +
|
| + else /* compose on row: implemented below. */
|
| + {
|
| + do_local_compose = 1;
|
| + /* This leaves the alpha channel in the output, so it has to be
|
| + * removed by the code below. Set the encoding to the 'OPTIMIZE'
|
| + * one so the code only has to hack on the pixels that require
|
| + * composition.
|
| + */
|
| + mode = PNG_ALPHA_OPTIMIZED;
|
| + }
|
| + }
|
| +
|
| + else /* output needs an alpha channel */
|
| + {
|
| + /* This is tricky because it happens before the swap operation has
|
| + * been accomplished; however, the swap does *not* swap the added
|
| + * alpha channel (weird API), so it must be added in the correct
|
| + * place.
|
| + */
|
| + png_uint_32 filler; /* opaque filler */
|
| + int where;
|
| +
|
| + if (linear != 0)
|
| + filler = 65535;
|
| +
|
| + else
|
| + filler = 255;
|
| +
|
| +# ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
| + if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
|
| + {
|
| + where = PNG_FILLER_BEFORE;
|
| + change &= ~PNG_FORMAT_FLAG_AFIRST;
|
| + }
|
| +
|
| + else
|
| +# endif
|
| + where = PNG_FILLER_AFTER;
|
| +
|
| + png_set_add_alpha(png_ptr, filler, where);
|
| + }
|
| +
|
| + /* This stops the (irrelevant) call to swap_alpha below. */
|
| + change &= ~PNG_FORMAT_FLAG_ALPHA;
|
| + }
|
| +
|
| + /* Now set the alpha mode correctly; this is always done, even if there is
|
| + * no alpha channel in either the input or the output because it correctly
|
| + * sets the output gamma.
|
| + */
|
| + png_set_alpha_mode_fixed(png_ptr, mode, output_gamma);
|
| +
|
| +# ifdef PNG_FORMAT_BGR_SUPPORTED
|
| + if ((change & PNG_FORMAT_FLAG_BGR) != 0)
|
| + {
|
| + /* Check only the output format; PNG is never BGR; don't do this if
|
| + * the output is gray, but fix up the 'format' value in that case.
|
| + */
|
| + if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
|
| + png_set_bgr(png_ptr);
|
| +
|
| + else
|
| + format &= ~PNG_FORMAT_FLAG_BGR;
|
| +
|
| + change &= ~PNG_FORMAT_FLAG_BGR;
|
| + }
|
| +# endif
|
| +
|
| +# ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
| + if ((change & PNG_FORMAT_FLAG_AFIRST) != 0)
|
| + {
|
| + /* Only relevant if there is an alpha channel - it's particularly
|
| + * important to handle this correctly because do_local_compose may
|
| + * be set above and then libpng will keep the alpha channel for this
|
| + * code to remove.
|
| + */
|
| + if ((format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + {
|
| + /* Disable this if doing a local background,
|
| + * TODO: remove this when local background is no longer required.
|
| + */
|
| + if (do_local_background != 2)
|
| + png_set_swap_alpha(png_ptr);
|
| + }
|
| +
|
| + else
|
| + format &= ~PNG_FORMAT_FLAG_AFIRST;
|
| +
|
| + change &= ~PNG_FORMAT_FLAG_AFIRST;
|
| + }
|
| +# endif
|
| +
|
| + /* If the *output* is 16-bit then we need to check for a byte-swap on this
|
| + * architecture.
|
| + */
|
| + if (linear != 0)
|
| + {
|
| + PNG_CONST png_uint_16 le = 0x0001;
|
| +
|
| + if ((*(png_const_bytep) & le) != 0)
|
| + png_set_swap(png_ptr);
|
| + }
|
| +
|
| + /* If change is not now 0 some transformation is missing - error out. */
|
| + if (change != 0)
|
| + png_error(png_ptr, "png_read_image: unsupported transformation");
|
| + }
|
| +
|
| + PNG_SKIP_CHUNKS(png_ptr);
|
| +
|
| + /* Update the 'info' structure and make sure the result is as required; first
|
| + * make sure to turn on the interlace handling if it will be required
|
| + * (because it can't be turned on *after* the call to png_read_update_info!)
|
| + *
|
| + * TODO: remove the do_local_background fixup below.
|
| + */
|
| + if (do_local_compose == 0 && do_local_background != 2)
|
| + passes = png_set_interlace_handling(png_ptr);
|
| +
|
| + png_read_update_info(png_ptr, info_ptr);
|
| +
|
| + {
|
| + png_uint_32 info_format = 0;
|
| +
|
| + if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
|
| + info_format |= PNG_FORMAT_FLAG_COLOR;
|
| +
|
| + if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
|
| + {
|
| + /* do_local_compose removes this channel below. */
|
| + if (do_local_compose == 0)
|
| + {
|
| + /* do_local_background does the same if required. */
|
| + if (do_local_background != 2 ||
|
| + (format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
| + info_format |= PNG_FORMAT_FLAG_ALPHA;
|
| + }
|
| + }
|
| +
|
| + else if (do_local_compose != 0) /* internal error */
|
| + png_error(png_ptr, "png_image_read: alpha channel lost");
|
| +
|
| + if (info_ptr->bit_depth == 16)
|
| + info_format |= PNG_FORMAT_FLAG_LINEAR;
|
| +
|
| +# ifdef PNG_FORMAT_BGR_SUPPORTED
|
| + if ((png_ptr->transformations & PNG_BGR) != 0)
|
| + info_format |= PNG_FORMAT_FLAG_BGR;
|
| +# endif
|
| +
|
| +# ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
| + if (do_local_background == 2)
|
| + {
|
| + if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
|
| + info_format |= PNG_FORMAT_FLAG_AFIRST;
|
| + }
|
| +
|
| + if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0 ||
|
| + ((png_ptr->transformations & PNG_ADD_ALPHA) != 0 &&
|
| + (png_ptr->flags & PNG_FLAG_FILLER_AFTER) == 0))
|
| + {
|
| + if (do_local_background == 2)
|
| + png_error(png_ptr, "unexpected alpha swap transformation");
|
| +
|
| + info_format |= PNG_FORMAT_FLAG_AFIRST;
|
| + }
|
| +# endif
|
| +
|
| + /* This is actually an internal error. */
|
| + if (info_format != format)
|
| + png_error(png_ptr, "png_read_image: invalid transformations");
|
| + }
|
| +
|
| + /* Now read the rows. If do_local_compose is set then it is necessary to use
|
| + * a local row buffer. The output will be GA, RGBA or BGRA and must be
|
| + * converted to G, RGB or BGR as appropriate. The 'local_row' member of the
|
| + * display acts as a flag.
|
| + */
|
| + {
|
| + png_voidp first_row = display->buffer;
|
| + ptrdiff_t row_bytes = display->row_stride;
|
| +
|
| + if (linear != 0)
|
| + row_bytes *= 2;
|
| +
|
| + /* The following expression is designed to work correctly whether it gives
|
| + * a signed or an unsigned result.
|
| + */
|
| + if (row_bytes < 0)
|
| + {
|
| + char *ptr = png_voidcast(char*, first_row);
|
| + ptr += (image->height-1) * (-row_bytes);
|
| + first_row = png_voidcast(png_voidp, ptr);
|
| + }
|
| +
|
| + display->first_row = first_row;
|
| + display->row_bytes = row_bytes;
|
| + }
|
| +
|
| + if (do_local_compose != 0)
|
| + {
|
| + int result;
|
| + png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
| +
|
| + display->local_row = row;
|
| + result = png_safe_execute(image, png_image_read_composite, display);
|
| + display->local_row = NULL;
|
| + png_free(png_ptr, row);
|
| +
|
| + return result;
|
| + }
|
| +
|
| + else if (do_local_background == 2)
|
| + {
|
| + int result;
|
| + png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
| +
|
| + display->local_row = row;
|
| + result = png_safe_execute(image, png_image_read_background, display);
|
| + display->local_row = NULL;
|
| + png_free(png_ptr, row);
|
| +
|
| + return result;
|
| + }
|
| +
|
| + else
|
| + {
|
| + png_alloc_size_t row_bytes = display->row_bytes;
|
| +
|
| + while (--passes >= 0)
|
| + {
|
| + png_uint_32 y = image->height;
|
| + png_bytep row = png_voidcast(png_bytep, display->first_row);
|
| +
|
| + while (y-- > 0)
|
| + {
|
| + png_read_row(png_ptr, row, NULL);
|
| + row += row_bytes;
|
| + }
|
| + }
|
| +
|
| + return 1;
|
| + }
|
| +}
|
| +
|
| +int PNGAPI
|
| +png_image_finish_read(png_imagep image, png_const_colorp background,
|
| + void *buffer, png_int_32 row_stride, void *colormap)
|
| +{
|
| + if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
| + {
|
| + png_uint_32 check;
|
| +
|
| + if (row_stride == 0)
|
| + row_stride = PNG_IMAGE_ROW_STRIDE(*image);
|
| +
|
| + if (row_stride < 0)
|
| + check = -row_stride;
|
| +
|
| + else
|
| + check = row_stride;
|
| +
|
| + if (image->opaque != NULL && buffer != NULL &&
|
| + check >= PNG_IMAGE_ROW_STRIDE(*image))
|
| + {
|
| + if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 ||
|
| + (image->colormap_entries > 0 && colormap != NULL))
|
| + {
|
| + int result;
|
| + png_image_read_control display;
|
| +
|
| + memset(&display, 0, (sizeof display));
|
| + display.image = image;
|
| + display.buffer = buffer;
|
| + display.row_stride = row_stride;
|
| + display.colormap = colormap;
|
| + display.background = background;
|
| + display.local_row = NULL;
|
| +
|
| + /* Choose the correct 'end' routine; for the color-map case all the
|
| + * setup has already been done.
|
| + */
|
| + if ((image->format & PNG_FORMAT_FLAG_COLORMAP) != 0)
|
| + result =
|
| + png_safe_execute(image, png_image_read_colormap, &display) &&
|
| + png_safe_execute(image, png_image_read_colormapped, &display);
|
| +
|
| + else
|
| + result =
|
| + png_safe_execute(image, png_image_read_direct, &display);
|
| +
|
| + png_image_free(image);
|
| + return result;
|
| + }
|
| +
|
| + else
|
| + return png_image_error(image,
|
| + "png_image_finish_read[color-map]: no color-map");
|
| + }
|
| +
|
| + else
|
| + return png_image_error(image,
|
| + "png_image_finish_read: invalid argument");
|
| + }
|
| +
|
| + else if (image != NULL)
|
| + return png_image_error(image,
|
| + "png_image_finish_read: damaged PNG_IMAGE_VERSION");
|
| +
|
| + return 0;
|
| +}
|
| +
|
| +#endif /* SIMPLIFIED_READ */
|
| +#endif /* READ */
|
|
|
Chromium Code Reviews
Issue 1591483003:
XFA: Upgrade libpng to 1.6.20. (Closed)
Base URL: https://pdfium.googlesource.com/pdfium.git@xfa