diff options
Diffstat (limited to 'third_party/libpng/pngread.c')
| -rw-r--r-- | third_party/libpng/pngread.c | 4136 |
1 files changed, 0 insertions, 4136 deletions
diff --git a/third_party/libpng/pngread.c b/third_party/libpng/pngread.c deleted file mode 100644 index 9cb4d2e41d..0000000000 --- a/third_party/libpng/pngread.c +++ /dev/null @@ -1,4136 +0,0 @@ - -/* 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 */ |