| |
| /* pngread.c - read a PNG file |
| * |
| * Last changed in libpng 1.6.0 [(PENDING RELEASE)] |
| * Copyright (c) 1998-2011 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) |
| { |
| int ok = 0; |
| |
| /* TODO: why does this happen here on read, but in png_write_IHDR on |
| * write? |
| */ |
| png_ptr->zstream.zalloc = png_zalloc; |
| png_ptr->zstream.zfree = png_zfree; |
| png_ptr->zstream.opaque = png_ptr; |
| |
| switch (inflateInit(&png_ptr->zstream)) |
| { |
| case Z_OK: |
| ok = 1; |
| break; |
| |
| case Z_MEM_ERROR: |
| png_warning(png_ptr, "zlib memory error"); |
| break; |
| |
| case Z_STREAM_ERROR: |
| png_warning(png_ptr, "zlib stream error"); |
| break; |
| |
| case Z_VERSION_ERROR: |
| png_warning(png_ptr, "zlib version error"); |
| break; |
| |
| default: |
| png_warning(png_ptr, "Unknown zlib error"); |
| break; |
| } |
| |
| if (ok) |
| { |
| png_ptr->zstream.next_out = png_ptr->zbuf; |
| png_ptr->zstream.avail_out = png_ptr->zbuf_size; |
| |
| /* 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; |
| } |
| |
| /* Else something went wrong in the zlib initialization above; it would |
| * much simplify this code if the creation of the zlib stuff was to be |
| * delayed until it is needed. |
| */ |
| png_destroy_read_struct(&png_ptr, NULL, NULL); |
| } |
| |
| return NULL; |
| } |
| |
| |
| #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_structp png_ptr, png_infop info_ptr) |
| { |
| 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; |
| |
| /* This should be a binary subdivision search or a hash for |
| * matching the chunk name rather than a linear search. |
| */ |
| if (chunk_name == png_IDAT) |
| if (png_ptr->mode & PNG_AFTER_IDAT) |
| png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT; |
| |
| 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 (png_chunk_unknown_handling(png_ptr, chunk_name) != |
| PNG_HANDLE_CHUNK_AS_DEFAULT) |
| { |
| if (chunk_name == png_IDAT) |
| png_ptr->mode |= PNG_HAVE_IDAT; |
| |
| png_handle_unknown(png_ptr, info_ptr, length); |
| |
| if (chunk_name == png_PLTE) |
| png_ptr->mode |= PNG_HAVE_PLTE; |
| |
| else if (chunk_name == png_IDAT) |
| { |
| if (!(png_ptr->mode & PNG_HAVE_IHDR)) |
| png_error(png_ptr, "Missing IHDR before IDAT"); |
| |
| else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && |
| !(png_ptr->mode & PNG_HAVE_PLTE)) |
| png_error(png_ptr, "Missing PLTE before IDAT"); |
| |
| break; |
| } |
| } |
| #endif |
| else if (chunk_name == png_PLTE) |
| png_handle_PLTE(png_ptr, info_ptr, length); |
| |
| else if (chunk_name == png_IDAT) |
| { |
| if (!(png_ptr->mode & PNG_HAVE_IHDR)) |
| png_error(png_ptr, "Missing IHDR before IDAT"); |
| |
| else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && |
| !(png_ptr->mode & PNG_HAVE_PLTE)) |
| png_error(png_ptr, "Missing PLTE before IDAT"); |
| |
| png_ptr->idat_size = length; |
| png_ptr->mode |= PNG_HAVE_IDAT; |
| break; |
| } |
| |
| #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); |
| } |
| } |
| #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ |
| |
| /* Optional call to update the users info_ptr structure */ |
| void PNGAPI |
| png_read_update_info(png_structp png_ptr, png_infop info_ptr) |
| { |
| png_debug(1, "in png_read_update_info"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| 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 |
| } |
| |
| #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_structp png_ptr) |
| { |
| png_debug(1, "in png_start_read_image"); |
| |
| if (png_ptr != NULL) |
| png_read_start_row(png_ptr); |
| } |
| #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ |
| |
| #ifdef PNG_SEQUENTIAL_READ_SUPPORTED |
| void PNGAPI |
| png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row) |
| { |
| int ret; |
| |
| 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"); |
| |
| png_ptr->zstream.next_out = png_ptr->row_buf; |
| png_ptr->zstream.avail_out = |
| (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth, |
| png_ptr->iwidth) + 1); |
| |
| do |
| { |
| if (!(png_ptr->zstream.avail_in)) |
| { |
| while (!png_ptr->idat_size) |
| { |
| png_crc_finish(png_ptr, 0); |
| |
| png_ptr->idat_size = png_read_chunk_header(png_ptr); |
| if (png_ptr->chunk_name != png_IDAT) |
| png_error(png_ptr, "Not enough image data"); |
| } |
| png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size; |
| png_ptr->zstream.next_in = png_ptr->zbuf; |
| if (png_ptr->zbuf_size > png_ptr->idat_size) |
| png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size; |
| png_crc_read(png_ptr, png_ptr->zbuf, |
| (png_size_t)png_ptr->zstream.avail_in); |
| png_ptr->idat_size -= png_ptr->zstream.avail_in; |
| } |
| |
| ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH); |
| |
| if (ret == Z_STREAM_END) |
| { |
| if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in || |
| png_ptr->idat_size) |
| png_benign_error(png_ptr, "Extra compressed data"); |
| png_ptr->mode |= PNG_AFTER_IDAT; |
| png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; |
| break; |
| } |
| |
| if (ret != Z_OK) |
| png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg : |
| "Decompression error"); |
| |
| } while (png_ptr->zstream.avail_out); |
| |
| 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: |
| */ |
| png_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_structp png_ptr, png_bytepp row, |
| png_bytepp display_row, png_uint_32 num_rows) |
| { |
| png_uint_32 i; |
| png_bytepp rp; |
| png_bytepp dp; |
| |
| png_debug(1, "in png_read_rows"); |
| |
| 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_structp png_ptr, png_bytepp image) |
| { |
| png_uint_32 i, image_height; |
| int pass, j; |
| png_bytepp rp; |
| |
| png_debug(1, "in png_read_image"); |
| |
| 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_structp png_ptr, png_infop info_ptr) |
| { |
| png_debug(1, "in png_read_end"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */ |
| |
| 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 (png_chunk_unknown_handling(png_ptr, chunk_name) != |
| PNG_HANDLE_CHUNK_AS_DEFAULT) |
| { |
| 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); |
| 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); |
| } 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_structp 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->zbuf); |
| png_free(png_ptr, png_ptr->big_row_buf); |
| png_free(png_ptr, png_ptr->big_prev_row); |
| png_free(png_ptr, png_ptr->chunkdata); |
| |
| #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 |
| |
| #ifdef PNG_READ_hIST_SUPPORTED |
| if (png_ptr->free_me & PNG_FREE_HIST) |
| png_free(png_ptr, png_ptr->hist); |
| png_ptr->free_me &= ~PNG_FREE_HIST; |
| #endif |
| |
| inflateEnd(&png_ptr->zstream); |
| |
| #ifdef PNG_PROGRESSIVE_READ_SUPPORTED |
| png_free(png_ptr, png_ptr->save_buffer); |
| #endif |
| |
| #ifdef PNG_PROGRESSIVE_READ_SUPPORTED |
| #ifdef PNG_TEXT_SUPPORTED |
| png_free(png_ptr, png_ptr->current_text); |
| #endif /* PNG_TEXT_SUPPORTED */ |
| #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ |
| |
| #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED |
| png_free(png_ptr, png_ptr->unknown_chunk.data); |
| #endif |
| |
| #ifdef PNG_HANDLE_AS_UNKNOWN_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_structp 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_structp 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_structp png_ptr, png_infop 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/png_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 * png_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. |
| */ |
| /* 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) |
| { |
| png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, image, |
| png_safe_error, png_safe_warning); |
| |
| 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) |
| { |
| png_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"); |
| } |
| |
| /* Utility to find the base format of a PNG file from a png_struct. */ |
| static png_uint_32 |
| png_image_format(png_structp png_ptr, png_infop info_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; |
| |
| else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS)) |
| format |= PNG_FORMAT_FLAG_ALPHA; |
| |
| if (png_ptr->bit_depth == 16) |
| format |= PNG_FORMAT_FLAG_LINEAR; |
| |
| return format; |
| } |
| |
| /* 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_structp png_ptr = image->opaque->png_ptr; |
| png_infop info_ptr = image->opaque->info_ptr; |
| |
| 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, info_ptr); |
| |
| image->format = format; |
| image->flags = 0; |
| |
| /* Now try to work out whether the color data does not match sRGB. */ |
| if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && |
| (info_ptr->valid & PNG_INFO_sRGB) == 0) |
| { |
| /* gamma is irrelevant because libpng does gamma correction, what |
| * matters is if the cHRM chunk doesn't match or, in the absence of |
| * cRHM, if the iCCP profile appears to have different end points. |
| */ |
| if (info_ptr->valid & PNG_INFO_cHRM) |
| { |
| /* TODO: this is a copy'n'paste from pngrutil.c, make a common |
| * checking function. This checks for a 1% error. |
| */ |
| /* The cHRM chunk is used in preference to iCCP */ |
| if (PNG_OUT_OF_RANGE(info_ptr->x_white, 31270, 1000) || |
| PNG_OUT_OF_RANGE(info_ptr->y_white, 32900, 1000) || |
| PNG_OUT_OF_RANGE(info_ptr->x_red, 64000, 1000) || |
| PNG_OUT_OF_RANGE(info_ptr->y_red, 33000, 1000) || |
| PNG_OUT_OF_RANGE(info_ptr->x_green, 30000, 1000) || |
| PNG_OUT_OF_RANGE(info_ptr->y_green, 60000, 1000) || |
| PNG_OUT_OF_RANGE(info_ptr->x_blue, 15000, 1000) || |
| PNG_OUT_OF_RANGE(info_ptr->y_blue, 6000, 1000)) |
| image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB; |
| } |
| |
| else if (info_ptr->valid & PNG_INFO_iCCP) |
| { |
| # if 0 |
| /* TODO: IMPLEMENT THIS! Remember to remove iCCP from |
| the chunks_to_ignore list */ |
| /* Here if we just have an iCCP chunk. */ |
| if (!png_iCCP_is_sRGB(png_ptr, info_ptr)) |
| # endif |
| image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB; |
| } |
| } |
| } |
| |
| return 1; |
| } |
| |
| #ifdef PNG_STDIO_SUPPORTED |
| int PNGAPI |
| png_image_begin_read_from_stdio(png_imagep image, FILE* file) |
| { |
| if (image != NULL) |
| { |
| 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"); |
| } |
| |
| return 0; |
| } |
| |
| int PNGAPI |
| png_image_begin_read_from_file(png_imagep image, const char *file_name) |
| { |
| if (image != NULL) |
| { |
| 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"); |
| } |
| |
| 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) |
| { |
| png_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) |
| { |
| 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"); |
| } |
| |
| return 0; |
| } |
| |
| /* Arguments to png_image_finish_read: */ |
| typedef struct |
| { |
| /* Arguments: */ |
| png_imagep image; |
| png_voidp buffer; |
| png_int_32 row_stride; |
| png_colorp background; |
| /* Local variables: */ |
| png_bytep local_row; |
| png_bytep first_row; |
| ptrdiff_t row_bytes; /* unsigned arithmetic step between rows */ |
| } png_image_read_control; |
| |
| /* 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_structp png_ptr = image->opaque->png_ptr; |
| png_byte interlace_type = png_ptr->interlaced; |
| int passes; |
| |
| switch (interlace_type) |
| { |
| 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; |
| unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1; |
| int pass; |
| |
| for (pass = 0; pass < passes; ++pass) |
| { |
| png_bytep row = display->first_row; |
| unsigned int startx, stepx, stepy; |
| png_uint_32 y; |
| |
| if (interlace_type == 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; |
| } |
| |
| /* The following are invariants across all the rows: */ |
| startx *= channels; |
| stepx *= channels; |
| |
| for (; y<height; y += stepy) |
| { |
| png_bytep inrow = display->local_row; |
| png_bytep outrow = row + startx; |
| png_const_bytep end_row = row + width * channels; |
| |
| /* Read the row, which is packed: */ |
| png_read_row(png_ptr, inrow, NULL); |
| |
| /* Now do the composition on each pixel in this row. */ |
| 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 */ |
| } |
| |
| row += display->row_bytes; |
| } |
| } |
| } |
| |
| 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_structp png_ptr = image->opaque->png_ptr; |
| png_infop info_ptr = image->opaque->info_ptr; |
| png_byte interlace_type = png_ptr->interlaced; |
| 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"); |
| |
| /* The palette code zaps PNG_GAMMA in place... */ |
| if ((png_ptr->color_type & PNG_COLOR_MASK_PALETTE) == 0 && |
| (png_ptr->transformations & PNG_GAMMA) == 0) |
| png_error(png_ptr, "lost gamma correction"); |
| |
| if (png_get_channels(png_ptr, info_ptr) != 2) |
| png_error(png_ptr, "lost/gained channels"); |
| |
| switch (interlace_type) |
| { |
| 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"); |
| } |
| |
| 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. |
| */ |
| for (pass = 0; pass < passes; ++pass) |
| { |
| png_bytep row = display->first_row; |
| unsigned int startx, stepx, stepy; |
| png_uint_32 y; |
| |
| if (interlace_type == 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 = display->local_row; |
| png_bytep outrow = row + startx; |
| png_const_bytep end_row = row + width; |
| |
| /* Read the row, which is packed: */ |
| png_read_row(png_ptr, inrow, NULL); |
| |
| /* Now do the composition on each pixel in this row. */ |
| 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 */ |
| } |
| |
| row += display->row_bytes; |
| } |
| } |
| |
| 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 = display->local_row; |
| png_bytep outrow = row + startx; |
| png_const_bytep end_row = row + width; |
| |
| /* Read the row, which is packed: */ |
| png_read_row(png_ptr, inrow, NULL); |
| |
| /* Now do the composition on each pixel in this row. */ |
| 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. |
| */ |
| { |
| unsigned int outchannels = png_get_channels(png_ptr, info_ptr); |
| int preserve_alpha = (image->format & PNG_FORMAT_FLAG_ALPHA) != 0; |
| int swap_alpha = 0; |
| |
| if (preserve_alpha && (image->format & PNG_FORMAT_FLAG_AFIRST)) |
| swap_alpha = 1; |
| |
| for (pass = 0; pass < passes; ++pass) |
| { |
| png_uint_16p row = (png_uint_16p)display->first_row; |
| unsigned int startx, stepx, stepy; /* all in pixels */ |
| png_uint_32 y; |
| |
| if (interlace_type == 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; |
| } |
| |
| startx *= outchannels; |
| stepx *= outchannels; |
| |
| for (; y<height; y += stepy) |
| { |
| png_uint_16p inrow; |
| png_uint_16p outrow = row + startx; |
| png_uint_16p end_row = row + width * outchannels; |
| |
| /* Read the row, which is packed: */ |
| png_read_row(png_ptr, display->local_row, NULL); |
| inrow = (png_uint_16p)display->local_row; |
| |
| /* Now do the pre-multiplication on each pixel in this row. |
| */ |
| 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 (outchannels > 1) |
| outrow[1 ^ swap_alpha] = alpha; |
| |
| inrow += 2; /* components and alpha channel */ |
| } |
| |
| row += display->row_bytes; |
| } |
| } |
| } |
| break; |
| } |
| |
| return 1; |
| } |
| |
| /* The guts of png_image_finish_read as a png_safe_execute callback. */ |
| static int |
| png_image_read_end(png_voidp argument) |
| { |
| png_image_read_control *display = png_voidcast(png_image_read_control*, |
| argument); |
| png_imagep image = display->image; |
| png_structp png_ptr = image->opaque->png_ptr; |
| png_infop 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, info_ptr); |
| 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) |
| 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->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"); |
| } |
| |
| # ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED |
| /* 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. |
| * |
| * TODO: make it so that this is an explicit list to process, not a list |
| * to ignore? |
| */ |
| { |
| static PNG_CONST png_byte chunks_to_ignore[] = { |
| 104, 73, 83, 84, '\0', /* hIST */ |
| 105, 84, 88, 116, '\0', /* iTXt */ |
| 111, 70, 70, 115, '\0', /* oFFs */ |
| 112, 67, 65, 76, '\0', /* pCAL */ |
| 112, 72, 89, 115, '\0', /* pHYs */ |
| 115, 67, 65, 76, '\0', /* sCAL */ |
| 115, 80, 76, 84, '\0', /* sPLT */ |
| 116, 69, 88, 116, '\0', /* tEXt */ |
| 116, 73, 77, 69, '\0', /* tIME */ |
| 122, 84, 88, 116, '\0' /* zTXt */ |
| }; |
| |
| /* Ignore unknown chunks */ |
| png_set_keep_unknown_chunks(png_ptr, 1 /* PNG_HANDLE_CHUNK_NEVER */, |
| NULL, 0); |
| |
| /* Ignore known but unused chunks */ |
| png_set_keep_unknown_chunks(png_ptr, 1 /* PNG_HANDLE_CHUNK_NEVER */, |
| chunks_to_ignore, (sizeof chunks_to_ignore)/5); |
| } |
| # endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */ |
| |
| /* 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 (png_ptr->transformations & PNG_SWAP_ALPHA || |
| ((png_ptr->transformations & PNG_ADD_ALPHA) != 0 && |
| (png_ptr->flags & PNG_FLAG_FILLER_AFTER) == 0)) |
| 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_bytep first_row = png_voidcast(png_bytep, display->buffer); |
| ptrdiff_t row_bytes = display->row_stride; |
| |
| if (linear) |
| row_bytes *= sizeof (png_uint_16); |
| |
| /* The following expression is designed to work correctly whether it gives |
| * a signed or an unsigned result. |
| */ |
| if (row_bytes < 0) |
| first_row += (image->height-1) * (-row_bytes); |
| |
| display->first_row = first_row; |
| display->row_bytes = row_bytes; |
| } |
| |
| if (do_local_compose) |
| { |
| int result; |
| png_bytep row = png_voidcast(png_bytep, 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_bytep row = png_voidcast(png_bytep, 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 = 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_colorp background, void *buffer, |
| png_int_32 row_stride) |
| { |
| if (image != NULL) |
| { |
| 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 (buffer != NULL && check >= PNG_IMAGE_ROW_STRIDE(*image)) |
| { |
| int result; |
| png_image_read_control display; |
| |
| png_memset(&display, 0, sizeof display); |
| display.image = image; |
| display.buffer = buffer; |
| display.row_stride = row_stride; |
| display.background = background; |
| display.local_row = NULL; |
| result = png_safe_execute(image, png_image_read_end, &display); |
| png_image_free(image); |
| return result; |
| } |
| |
| else |
| return png_image_error(image, |
| "png_image_finish_read: invalid argument"); |
| } |
| |
| return 0; |
| } |
| |
| #endif /* PNG_SIMPLIFIED_READ_SUPPORTED */ |
| #endif /* PNG_READ_SUPPORTED */ |