/* pngwrite.c - general routines to write a PNG file * * Copyright (c) 2018-2024 Cosmin Truta * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson * Copyright (c) 1996-1997 Andreas Dilger * 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 */ #include "pngpriv.h" #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED # include <errno.h> #endif /* SIMPLIFIED_WRITE_STDIO */ #ifdef PNG_WRITE_SUPPORTED #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED /* Write out all the unknown chunks for the current given location */ static void write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr, unsigned int where) { if (info_ptr->unknown_chunks_num != 0) { png_const_unknown_chunkp up; png_debug(5, "writing extra chunks"); for (up = info_ptr->unknown_chunks; up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num; ++up) if ((up->location & where) != 0) { /* If per-chunk unknown chunk handling is enabled use it, otherwise * just write the chunks the application has set. */ #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED int keep = png_handle_as_unknown(png_ptr, up->name); /* NOTE: this code is radically different from the read side in the * matter of handling an ancillary unknown chunk. In the read side * the default behavior is to discard it, in the code below the default * behavior is to write it. Critical chunks are, however, only * written if explicitly listed or if the default is set to write all * unknown chunks. * * The default handling is also slightly weird - it is not possible to * stop the writing of all unsafe-to-copy chunks! * * TODO: REVIEW: this would seem to be a bug. */ if (keep != PNG_HANDLE_CHUNK_NEVER && ((up->name[3] & 0x20) /* safe-to-copy overrides everything */ || keep == PNG_HANDLE_CHUNK_ALWAYS || (keep == PNG_HANDLE_CHUNK_AS_DEFAULT && png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS))) #endif { /* TODO: review, what is wrong with a zero length unknown chunk? */ if (up->size == 0) png_warning(png_ptr, "Writing zero-length unknown chunk"); png_write_chunk(png_ptr, up->name, up->data, up->size); } } } } #endif /* WRITE_UNKNOWN_CHUNKS */ /* Writes all the PNG information. This is the suggested way to use the * library. If you have a new chunk to add, make a function to write it, * and put it in the correct location here. If you want the chunk written * after the image data, put it in png_write_end(). I strongly encourage * you to supply a PNG_INFO_<chunk> flag, and check info_ptr->valid before * writing the chunk, as that will keep the code from breaking if you want * to just write a plain PNG file. If you have long comments, I suggest * writing them in png_write_end(), and compressing them. */ void PNGAPI png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr) { png_debug(1, "in png_write_info_before_PLTE"); if (png_ptr == NULL || info_ptr == NULL) return; if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0) { /* Write PNG signature */ png_write_sig(png_ptr); #ifdef PNG_MNG_FEATURES_SUPPORTED if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \ png_ptr->mng_features_permitted != 0) { png_warning(png_ptr, "MNG features are not allowed in a PNG datastream"); png_ptr->mng_features_permitted = 0; } #endif /* Write IHDR information. */ png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height, info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type, info_ptr->filter_type, #ifdef PNG_WRITE_INTERLACING_SUPPORTED info_ptr->interlace_type #else 0 #endif ); /* The rest of these check to see if the valid field has the appropriate * flag set, and if it does, writes the chunk. * * 1.6.0: COLORSPACE support controls the writing of these chunks too, and * the chunks will be written if the WRITE routine is there and * information * is available in the COLORSPACE. (See * png_colorspace_sync_info in png.c for where the valid flags get set.) * * Under certain circumstances the colorspace can be invalidated without * syncing the info_struct 'valid' flags; this happens if libpng detects * an error and calls png_error while the color space is being set, yet * the application continues writing the PNG. So check the 'invalid' * flag here too. */ #ifdef PNG_GAMMA_SUPPORTED # ifdef PNG_WRITE_gAMA_SUPPORTED if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 && (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 && (info_ptr->valid & PNG_INFO_gAMA) != 0) png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma); # endif #endif #ifdef PNG_COLORSPACE_SUPPORTED /* Write only one of sRGB or an ICC profile. If a profile was supplied * and it matches one of the known sRGB ones issue a warning. */ # ifdef PNG_WRITE_iCCP_SUPPORTED if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 && (info_ptr->valid & PNG_INFO_iCCP) != 0) { # ifdef PNG_WRITE_sRGB_SUPPORTED if ((info_ptr->valid & PNG_INFO_sRGB) != 0) png_app_warning(png_ptr, "profile matches sRGB but writing iCCP instead"); # endif png_write_iCCP(png_ptr, info_ptr->iccp_name, info_ptr->iccp_profile); } # ifdef PNG_WRITE_sRGB_SUPPORTED else # endif # endif # ifdef PNG_WRITE_sRGB_SUPPORTED if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 && (info_ptr->valid & PNG_INFO_sRGB) != 0) png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent); # endif /* WRITE_sRGB */ #endif /* COLORSPACE */ #ifdef PNG_WRITE_sBIT_SUPPORTED if ((info_ptr->valid & PNG_INFO_sBIT) != 0) png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type); #endif #ifdef PNG_COLORSPACE_SUPPORTED # ifdef PNG_WRITE_cHRM_SUPPORTED if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 && (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 && (info_ptr->valid & PNG_INFO_cHRM) != 0) png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy); # endif #endif #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR); #endif png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE; } } void PNGAPI png_write_info(png_structrp png_ptr, png_const_inforp info_ptr) { #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED) int i; #endif png_debug(1, "in png_write_info"); if (png_ptr == NULL || info_ptr == NULL) return; png_write_info_before_PLTE(png_ptr, info_ptr); if ((info_ptr->valid & PNG_INFO_PLTE) != 0) png_write_PLTE(png_ptr, info_ptr->palette, (png_uint_32)info_ptr->num_palette); else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) png_error(png_ptr, "Valid palette required for paletted images"); #ifdef PNG_WRITE_tRNS_SUPPORTED if ((info_ptr->valid & PNG_INFO_tRNS) !=0) { #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED /* Invert the alpha channel (in tRNS) */ if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 && info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { int j, jend; jend = info_ptr->num_trans; if (jend > PNG_MAX_PALETTE_LENGTH) jend = PNG_MAX_PALETTE_LENGTH; for (j = 0; j<jend; ++j) info_ptr->trans_alpha[j] = (png_byte)(255 - info_ptr->trans_alpha[j]); } #endif png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color), info_ptr->num_trans, info_ptr->color_type); } #endif #ifdef PNG_WRITE_bKGD_SUPPORTED if ((info_ptr->valid & PNG_INFO_bKGD) != 0) png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type); #endif #ifdef PNG_WRITE_eXIf_SUPPORTED if ((info_ptr->valid & PNG_INFO_eXIf) != 0) { png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif); png_ptr->mode |= PNG_WROTE_eXIf; } #endif #ifdef PNG_WRITE_hIST_SUPPORTED if ((info_ptr->valid & PNG_INFO_hIST) != 0) png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette); #endif #ifdef PNG_WRITE_oFFs_SUPPORTED if ((info_ptr->valid & PNG_INFO_oFFs) != 0) png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset, info_ptr->offset_unit_type); #endif #ifdef PNG_WRITE_pCAL_SUPPORTED if ((info_ptr->valid & PNG_INFO_pCAL) != 0) png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0, info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams, info_ptr->pcal_units, info_ptr->pcal_params); #endif #ifdef PNG_WRITE_sCAL_SUPPORTED if ((info_ptr->valid & PNG_INFO_sCAL) != 0) png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit, info_ptr->scal_s_width, info_ptr->scal_s_height); #endif /* sCAL */ #ifdef PNG_WRITE_pHYs_SUPPORTED if ((info_ptr->valid & PNG_INFO_pHYs) != 0) png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit, info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type); #endif /* pHYs */ #ifdef PNG_WRITE_tIME_SUPPORTED if ((info_ptr->valid & PNG_INFO_tIME) != 0) { png_write_tIME(png_ptr, &(info_ptr->mod_time)); png_ptr->mode |= PNG_WROTE_tIME; } #endif /* tIME */ #ifdef PNG_WRITE_sPLT_SUPPORTED if ((info_ptr->valid & PNG_INFO_sPLT) != 0) for (i = 0; i < (int)info_ptr->splt_palettes_num; i++) png_write_sPLT(png_ptr, info_ptr->splt_palettes + i); #endif /* sPLT */ #ifdef PNG_WRITE_TEXT_SUPPORTED /* Check to see if we need to write text chunks */ for (i = 0; i < info_ptr->num_text; i++) { png_debug2(2, "Writing header text chunk %d, type %d", i, info_ptr->text[i].compression); /* An internationalized chunk? */ if (info_ptr->text[i].compression > 0) { #ifdef PNG_WRITE_iTXt_SUPPORTED /* Write international chunk */ png_write_iTXt(png_ptr, info_ptr->text[i].compression, info_ptr->text[i].key, info_ptr->text[i].lang, info_ptr->text[i].lang_key, info_ptr->text[i].text); /* Mark this chunk as written */ if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE) info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR; else info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR; #else png_warning(png_ptr, "Unable to write international text"); #endif } /* If we want a compressed text chunk */ else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt) { #ifdef PNG_WRITE_zTXt_SUPPORTED /* Write compressed chunk */ png_write_zTXt(png_ptr, info_ptr->text[i].key, info_ptr->text[i].text, info_ptr->text[i].compression); /* Mark this chunk as written */ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR; #else png_warning(png_ptr, "Unable to write compressed text"); #endif } else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE) { #ifdef PNG_WRITE_tEXt_SUPPORTED /* Write uncompressed chunk */ png_write_tEXt(png_ptr, info_ptr->text[i].key, info_ptr->text[i].text, 0); /* Mark this chunk as written */ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR; #else /* Can't get here */ png_warning(png_ptr, "Unable to write uncompressed text"); #endif } } #endif /* tEXt */ #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE); #endif } /* Writes the end of the PNG file. If you don't want to write comments or * time information, you can pass NULL for info. If you already wrote these * in png_write_info(), do not write them again here. If you have long * comments, I suggest writing them here, and compressing them. */ void PNGAPI png_write_end(png_structrp png_ptr, png_inforp info_ptr) { png_debug(1, "in png_write_end"); if (png_ptr == NULL) return; if ((png_ptr->mode & PNG_HAVE_IDAT) == 0) png_error(png_ptr, "No IDATs written into file"); #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_palette_max >= png_ptr->num_palette) png_benign_error(png_ptr, "Wrote palette index exceeding num_palette"); #endif /* See if user wants us to write information chunks */ if (info_ptr != NULL) { #ifdef PNG_WRITE_TEXT_SUPPORTED int i; /* local index variable */ #endif #ifdef PNG_WRITE_tIME_SUPPORTED /* Check to see if user has supplied a time chunk */ if ((info_ptr->valid & PNG_INFO_tIME) != 0 && (png_ptr->mode & PNG_WROTE_tIME) == 0) png_write_tIME(png_ptr, &(info_ptr->mod_time)); #endif #ifdef PNG_WRITE_TEXT_SUPPORTED /* Loop through comment chunks */ for (i = 0; i < info_ptr->num_text; i++) { png_debug2(2, "Writing trailer text chunk %d, type %d", i, info_ptr->text[i].compression); /* An internationalized chunk? */ if (info_ptr->text[i].compression > 0) { #ifdef PNG_WRITE_iTXt_SUPPORTED /* Write international chunk */ png_write_iTXt(png_ptr, info_ptr->text[i].compression, info_ptr->text[i].key, info_ptr->text[i].lang, info_ptr->text[i].lang_key, info_ptr->text[i].text); /* Mark this chunk as written */ if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE) info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR; else info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR; #else png_warning(png_ptr, "Unable to write international text"); #endif } else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt) { #ifdef PNG_WRITE_zTXt_SUPPORTED /* Write compressed chunk */ png_write_zTXt(png_ptr, info_ptr->text[i].key, info_ptr->text[i].text, info_ptr->text[i].compression); /* Mark this chunk as written */ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR; #else png_warning(png_ptr, "Unable to write compressed text"); #endif } else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE) { #ifdef PNG_WRITE_tEXt_SUPPORTED /* Write uncompressed chunk */ png_write_tEXt(png_ptr, info_ptr->text[i].key, info_ptr->text[i].text, 0); /* Mark this chunk as written */ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR; #else png_warning(png_ptr, "Unable to write uncompressed text"); #endif } } #endif #ifdef PNG_WRITE_eXIf_SUPPORTED if ((info_ptr->valid & PNG_INFO_eXIf) != 0 && (png_ptr->mode & PNG_WROTE_eXIf) == 0) png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif); #endif #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT); #endif } png_ptr->mode |= PNG_AFTER_IDAT; /* Write end of PNG file */ png_write_IEND(png_ptr); /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03, * and restored again in libpng-1.2.30, may cause some applications that * do not set png_ptr->output_flush_fn to crash. If your application * experiences a problem, please try building libpng with * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to * png-mng-implement at lists.sf.net . */ #ifdef PNG_WRITE_FLUSH_SUPPORTED # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED png_flush(png_ptr); # endif #endif } #ifdef PNG_CONVERT_tIME_SUPPORTED void PNGAPI png_convert_from_struct_tm(png_timep ptime, const struct tm * ttime) { png_debug(1, "in png_convert_from_struct_tm"); ptime->year = (png_uint_16)(1900 + ttime->tm_year); ptime->month = (png_byte)(ttime->tm_mon + 1); ptime->day = (png_byte)ttime->tm_mday; ptime->hour = (png_byte)ttime->tm_hour; ptime->minute = (png_byte)ttime->tm_min; ptime->second = (png_byte)ttime->tm_sec; } void PNGAPI png_convert_from_time_t(png_timep ptime, time_t ttime) { struct tm *tbuf; png_debug(1, "in png_convert_from_time_t"); tbuf = gmtime(&ttime); if (tbuf == NULL) { /* TODO: add a safe function which takes a png_ptr argument and raises * a png_error if the ttime argument is invalid and the call to gmtime * fails as a consequence. */ memset(ptime, 0, sizeof(*ptime)); return; } png_convert_from_struct_tm(ptime, tbuf); } #endif /* Initialize png_ptr structure, and allocate any memory needed */ PNG_FUNCTION(png_structp,PNGAPI png_create_write_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_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr, error_fn, warn_fn, NULL, NULL, NULL); #else return png_create_write_struct_2(user_png_ver, error_ptr, error_fn, warn_fn, NULL, NULL, NULL); } /* Alternate initialize png_ptr structure, and allocate any memory needed */ PNG_FUNCTION(png_structp,PNGAPI png_create_write_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_structrp 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) { /* Set the zlib control values to defaults; they can be overridden by the * application after the struct has been created. */ png_ptr->zbuffer_size = PNG_ZBUF_SIZE; /* The 'zlib_strategy' setting is irrelevant because png_default_claim in * pngwutil.c defaults it according to whether or not filters will be * used, and ignores this setting. */ png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY; png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION; png_ptr->zlib_mem_level = 8; png_ptr->zlib_window_bits = 15; png_ptr->zlib_method = 8; #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY; png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION; png_ptr->zlib_text_mem_level = 8; png_ptr->zlib_text_window_bits = 15; png_ptr->zlib_text_method = 8; #endif /* WRITE_COMPRESSED_TEXT */ /* This is a highly dubious configuration option; by default it is off, * but it may be appropriate for private builds that are testing * extensions not conformant to the current specification, or of * applications that must not fail to write at all costs! */ #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED /* In stable builds only warn if an application error can be completely * handled. */ png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN; #endif /* App warnings are warnings in release (or release candidate) builds but * are errors during development. */ #if PNG_RELEASE_BUILD png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN; #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_write_fn(png_ptr, NULL, NULL, NULL); } return png_ptr; } /* Write a few rows of image data. If the image is interlaced, * either you will have to write the 7 sub images, or, if you * have called png_set_interlace_handling(), you will have to * "write" the image seven times. */ void PNGAPI png_write_rows(png_structrp png_ptr, png_bytepp row, png_uint_32 num_rows) { png_uint_32 i; /* row counter */ png_bytepp rp; /* row pointer */ png_debug(1, "in png_write_rows"); if (png_ptr == NULL) return; /* Loop through the rows */ for (i = 0, rp = row; i < num_rows; i++, rp++) { png_write_row(png_ptr, *rp); } } /* Write the image. You only need to call this function once, even * if you are writing an interlaced image. */ void PNGAPI png_write_image(png_structrp png_ptr, png_bytepp image) { png_uint_32 i; /* row index */ int pass, num_pass; /* pass variables */ png_bytepp rp; /* points to current row */ if (png_ptr == NULL) return; png_debug(1, "in png_write_image"); #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* Initialize interlace handling. If image is not interlaced, * this will set pass to 1 */ num_pass = png_set_interlace_handling(png_ptr); #else num_pass = 1; #endif /* Loop through passes */ for (pass = 0; pass < num_pass; pass++) { /* Loop through image */ for (i = 0, rp = image; i < png_ptr->height; i++, rp++) { png_write_row(png_ptr, *rp); } } } #ifdef PNG_MNG_FEATURES_SUPPORTED /* Performs intrapixel differencing */ static void png_do_write_intrapixel(png_row_infop row_info, png_bytep row) { png_debug(1, "in png_do_write_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)(*rp - *(rp + 1)); *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1)); } } #ifdef PNG_WRITE_16BIT_SUPPORTED 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 = (png_uint_32)(*(rp ) << 8) | *(rp + 1); png_uint_32 s1 = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3); png_uint_32 s2 = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5); png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL); png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL); *(rp ) = (png_byte)(red >> 8); *(rp + 1) = (png_byte)red; *(rp + 4) = (png_byte)(blue >> 8); *(rp + 5) = (png_byte)blue; } } #endif /* WRITE_16BIT */ } } #endif /* MNG_FEATURES */ /* Called by user to write a row of image data */ void PNGAPI png_write_row(png_structrp png_ptr, png_const_bytep row) { /* 1.5.6: moved from png_struct to be a local structure: */ png_row_info row_info; png_debug2(1, "in png_write_row (row %u, pass %d)", png_ptr->row_number, png_ptr->pass); if (png_ptr == NULL) return; /* Initialize transformations and other stuff if first time */ if (png_ptr->row_number == 0 && png_ptr->pass == 0) { /* Make sure we wrote the header info */ if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0) png_error(png_ptr, "png_write_info was never called before png_write_row"); /* 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_WRITE_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_WRITE_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_WRITE_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_WRITE_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_WRITE_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_WRITE_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_WRITE_SWAP_SUPPORTED is not defined"); #endif png_write_start_row(png_ptr); } #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* If interlaced and not interested in row, return */ if (png_ptr->interlaced != 0 && (png_ptr->transformations & PNG_INTERLACE) != 0) { switch (png_ptr->pass) { case 0: if ((png_ptr->row_number & 0x07) != 0) { png_write_finish_row(png_ptr); return; } break; case 1: if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5) { png_write_finish_row(png_ptr); return; } break; case 2: if ((png_ptr->row_number & 0x07) != 4) { png_write_finish_row(png_ptr); return; } break; case 3: if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3) { png_write_finish_row(png_ptr); return; } break; case 4: if ((png_ptr->row_number & 0x03) != 2) { png_write_finish_row(png_ptr); return; } break; case 5: if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2) { png_write_finish_row(png_ptr); return; } break; case 6: if ((png_ptr->row_number & 0x01) == 0) { png_write_finish_row(png_ptr); return; } break; default: /* error: ignore it */ break; } } #endif /* Set up row info for transformations */ row_info.color_type = png_ptr->color_type; row_info.width = png_ptr->usr_width; row_info.channels = png_ptr->usr_channels; row_info.bit_depth = png_ptr->usr_bit_depth; row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels); row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width); png_debug1(3, "row_info->color_type = %d", row_info.color_type); png_debug1(3, "row_info->width = %u", row_info.width); png_debug1(3, "row_info->channels = %d", row_info.channels); png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth); png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth); png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes); /* Copy user's row into buffer, leaving room for filter byte. */ memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes); #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* Handle interlacing */ if (png_ptr->interlaced && png_ptr->pass < 6 && (png_ptr->transformations & PNG_INTERLACE) != 0) { png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass); /* This should always get caught above, but still ... */ if (row_info.width == 0) { png_write_finish_row(png_ptr); return; } } #endif #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED /* Handle other transformations */ if (png_ptr->transformations != 0) png_do_write_transformations(png_ptr, &row_info); #endif /* At this point the row_info pixel depth must match the 'transformed' depth, * which is also the output depth. */ if (row_info.pixel_depth != png_ptr->pixel_depth || row_info.pixel_depth != png_ptr->transformed_pixel_depth) png_error(png_ptr, "internal write transform logic error"); #ifdef PNG_MNG_FEATURES_SUPPORTED /* Write filter_method 64 (intrapixel differencing) only if * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and * 2. Libpng did not write a PNG signature (this filter_method is only * used in PNG datastreams that are embedded in MNG datastreams) and * 3. The application called png_permit_mng_features with a mask that * included PNG_FLAG_MNG_FILTER_64 and * 4. The filter_method is 64 and * 5. The color_type is RGB or RGBA */ if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 && (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING)) { /* Intrapixel differencing */ png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1); } #endif /* Added at libpng-1.5.10 */ #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED /* Check for out-of-range palette index */ if (row_info.color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_palette_max >= 0) png_do_check_palette_indexes(png_ptr, &row_info); #endif /* Find a filter if necessary, filter the row and write it out. */ png_write_find_filter(png_ptr, &row_info); if (png_ptr->write_row_fn != NULL) (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass); } #ifdef PNG_WRITE_FLUSH_SUPPORTED /* Set the automatic flush interval or 0 to turn flushing off */ void PNGAPI png_set_flush(png_structrp png_ptr, int nrows) { png_debug(1, "in png_set_flush"); if (png_ptr == NULL) return; png_ptr->flush_dist = (nrows < 0 ? 0 : (png_uint_32)nrows); } /* Flush the current output buffers now */ void PNGAPI png_write_flush(png_structrp png_ptr) { png_debug(1, "in png_write_flush"); if (png_ptr == NULL) return; /* We have already written out all of the data */ if (png_ptr->row_number >= png_ptr->num_rows) return; png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH); png_ptr->flush_rows = 0; png_flush(png_ptr); } #endif /* WRITE_FLUSH */ /* Free any memory used in png_ptr struct without freeing the struct itself. */ static void png_write_destroy(png_structrp png_ptr) { png_debug(1, "in png_write_destroy"); /* Free any memory zlib uses */ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0) deflateEnd(&png_ptr->zstream); /* Free our memory. png_free checks NULL for us. */ png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list); png_free(png_ptr, png_ptr->row_buf); png_ptr->row_buf = NULL; #ifdef PNG_WRITE_FILTER_SUPPORTED png_free(png_ptr, png_ptr->prev_row); png_free(png_ptr, png_ptr->try_row); png_free(png_ptr, png_ptr->tst_row); png_ptr->prev_row = NULL; png_ptr->try_row = NULL; png_ptr->tst_row = NULL; #endif #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED png_free(png_ptr, png_ptr->chunk_list); png_ptr->chunk_list = NULL; #endif /* The error handling and memory handling information is left intact at this * point: the jmp_buf may still have to be freed. See png_destroy_png_struct * for how this happens. */ } /* Free all memory used by the write. * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free * the passed in info_structs but it would quietly fail to free any of the data * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it * has no png_ptr.) */ void PNGAPI png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr) { png_debug(1, "in png_destroy_write_struct"); if (png_ptr_ptr != NULL) { png_structrp png_ptr = *png_ptr_ptr; if (png_ptr != NULL) /* added in libpng 1.6.0 */ { png_destroy_info_struct(png_ptr, info_ptr_ptr); *png_ptr_ptr = NULL; png_write_destroy(png_ptr); png_destroy_png_struct(png_ptr); } } } /* Allow the application to select one or more row filters to use. */ void PNGAPI png_set_filter(png_structrp png_ptr, int method, int filters) { png_debug(1, "in png_set_filter"); if (png_ptr == NULL) return; #ifdef PNG_MNG_FEATURES_SUPPORTED if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 && (method == PNG_INTRAPIXEL_DIFFERENCING)) method = PNG_FILTER_TYPE_BASE; #endif if (method == PNG_FILTER_TYPE_BASE) { switch (filters & (PNG_ALL_FILTERS | 0x07)) { #ifdef PNG_WRITE_FILTER_SUPPORTED case 5: case 6: case 7: png_app_error(png_ptr, "Unknown row filter for method 0"); #endif /* WRITE_FILTER */ /* FALLTHROUGH */ case PNG_FILTER_VALUE_NONE: png_ptr->do_filter = PNG_FILTER_NONE; break; #ifdef PNG_WRITE_FILTER_SUPPORTED case PNG_FILTER_VALUE_SUB: png_ptr->do_filter = PNG_FILTER_SUB; break; case PNG_FILTER_VALUE_UP: png_ptr->do_filter = PNG_FILTER_UP; break; case PNG_FILTER_VALUE_AVG: png_ptr->do_filter = PNG_FILTER_AVG; break; case PNG_FILTER_VALUE_PAETH: png_ptr->do_filter = PNG_FILTER_PAETH; break; default: png_ptr->do_filter = (png_byte)filters; break; #else default: png_app_error(png_ptr, "Unknown row filter for method 0"); #endif /* WRITE_FILTER */ } #ifdef PNG_WRITE_FILTER_SUPPORTED /* If we have allocated the row_buf, this means we have already started * with the image and we should have allocated all of the filter buffers * that have been selected. If prev_row isn't already allocated, then * it is too late to start using the filters that need it, since we * will be missing the data in the previous row. If an application * wants to start and stop using particular filters during compression, * it should start out with all of the filters, and then remove them * or add them back after the start of compression. * * NOTE: this is a nasty constraint on the code, because it means that the * prev_row buffer must be maintained even if there are currently no * 'prev_row' requiring filters active. */ if (png_ptr->row_buf != NULL) { int num_filters; png_alloc_size_t buf_size; /* Repeat the checks in png_write_start_row; 1 pixel high or wide * images cannot benefit from certain filters. If this isn't done here * the check below will fire on 1 pixel high images. */ if (png_ptr->height == 1) filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH); if (png_ptr->width == 1) filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH); if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0 && png_ptr->prev_row == NULL) { /* This is the error case, however it is benign - the previous row * is not available so the filter can't be used. Just warn here. */ png_app_warning(png_ptr, "png_set_filter: UP/AVG/PAETH cannot be added after start"); filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH); } num_filters = 0; if (filters & PNG_FILTER_SUB) num_filters++; if (filters & PNG_FILTER_UP) num_filters++; if (filters & PNG_FILTER_AVG) num_filters++; if (filters & PNG_FILTER_PAETH) num_filters++; /* Allocate needed row buffers if they have not already been * allocated. */ buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth, png_ptr->width) + 1; if (png_ptr->try_row == NULL) png_ptr->try_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size)); if (num_filters > 1) { if (png_ptr->tst_row == NULL) png_ptr->tst_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size)); } } png_ptr->do_filter = (png_byte)filters; #endif } else png_error(png_ptr, "Unknown custom filter method"); } #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */ /* Provide floating and fixed point APIs */ #ifdef PNG_FLOATING_POINT_SUPPORTED void PNGAPI png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method, int num_weights, png_const_doublep filter_weights, png_const_doublep filter_costs) { PNG_UNUSED(png_ptr) PNG_UNUSED(heuristic_method) PNG_UNUSED(num_weights) PNG_UNUSED(filter_weights) PNG_UNUSED(filter_costs) } #endif /* FLOATING_POINT */ #ifdef PNG_FIXED_POINT_SUPPORTED void PNGAPI png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method, int num_weights, png_const_fixed_point_p filter_weights, png_const_fixed_point_p filter_costs) { PNG_UNUSED(png_ptr) PNG_UNUSED(heuristic_method) PNG_UNUSED(num_weights) PNG_UNUSED(filter_weights) PNG_UNUSED(filter_costs) } #endif /* FIXED_POINT */ #endif /* WRITE_WEIGHTED_FILTER */ #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED void PNGAPI png_set_compression_level(png_structrp png_ptr, int level) { png_debug(1, "in png_set_compression_level"); if (png_ptr == NULL) return; png_ptr->zlib_level = level; } void PNGAPI png_set_compression_mem_level(png_structrp png_ptr, int mem_level) { png_debug(1, "in png_set_compression_mem_level"); if (png_ptr == NULL) return; png_ptr->zlib_mem_level = mem_level; } void PNGAPI png_set_compression_strategy(png_structrp png_ptr, int strategy) { png_debug(1, "in png_set_compression_strategy"); if (png_ptr == NULL) return; /* The flag setting here prevents the libpng dynamic selection of strategy. */ png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY; png_ptr->zlib_strategy = strategy; } /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a * smaller value of window_bits if it can do so safely. */ void PNGAPI png_set_compression_window_bits(png_structrp png_ptr, int window_bits) { png_debug(1, "in png_set_compression_window_bits"); if (png_ptr == NULL) return; /* Prior to 1.6.0 this would warn but then set the window_bits value. This * meant that negative window bits values could be selected that would cause * libpng to write a non-standard PNG file with raw deflate or gzip * compressed IDAT or ancillary chunks. Such files can be read and there is * no warning on read, so this seems like a very bad idea. */ if (window_bits > 15) { png_warning(png_ptr, "Only compression windows <= 32k supported by PNG"); window_bits = 15; } else if (window_bits < 8) { png_warning(png_ptr, "Only compression windows >= 256 supported by PNG"); window_bits = 8; } png_ptr->zlib_window_bits = window_bits; } void PNGAPI png_set_compression_method(png_structrp png_ptr, int method) { png_debug(1, "in png_set_compression_method"); if (png_ptr == NULL) return; /* This would produce an invalid PNG file if it worked, but it doesn't and * deflate will fault it, so it is harmless to just warn here. */ if (method != 8) png_warning(png_ptr, "Only compression method 8 is supported by PNG"); png_ptr->zlib_method = method; } #endif /* WRITE_CUSTOMIZE_COMPRESSION */ /* The following were added to libpng-1.5.4 */ #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED void PNGAPI png_set_text_compression_level(png_structrp png_ptr, int level) { png_debug(1, "in png_set_text_compression_level"); if (png_ptr == NULL) return; png_ptr->zlib_text_level = level; } void PNGAPI png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level) { png_debug(1, "in png_set_text_compression_mem_level"); if (png_ptr == NULL) return; png_ptr->zlib_text_mem_level = mem_level; } void PNGAPI png_set_text_compression_strategy(png_structrp png_ptr, int strategy) { png_debug(1, "in png_set_text_compression_strategy"); if (png_ptr == NULL) return; png_ptr->zlib_text_strategy = strategy; } /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a * smaller value of window_bits if it can do so safely. */ void PNGAPI png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits) { png_debug(1, "in png_set_text_compression_window_bits"); if (png_ptr == NULL) return; if (window_bits > 15) { png_warning(png_ptr, "Only compression windows <= 32k supported by PNG"); window_bits = 15; } else if (window_bits < 8) { png_warning(png_ptr, "Only compression windows >= 256 supported by PNG"); window_bits = 8; } png_ptr->zlib_text_window_bits = window_bits; } void PNGAPI png_set_text_compression_method(png_structrp png_ptr, int method) { png_debug(1, "in png_set_text_compression_method"); if (png_ptr == NULL) return; if (method != 8) png_warning(png_ptr, "Only compression method 8 is supported by PNG"); png_ptr->zlib_text_method = method; } #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */ /* end of API added to libpng-1.5.4 */ void PNGAPI png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn) { png_debug(1, "in png_set_write_status_fn"); if (png_ptr == NULL) return; png_ptr->write_row_fn = write_row_fn; } #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED void PNGAPI png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr write_user_transform_fn) { png_debug(1, "in png_set_write_user_transform_fn"); if (png_ptr == NULL) return; png_ptr->transformations |= PNG_USER_TRANSFORM; png_ptr->write_user_transform_fn = write_user_transform_fn; } #endif #ifdef PNG_INFO_IMAGE_SUPPORTED void PNGAPI png_write_png(png_structrp png_ptr, png_inforp info_ptr, int transforms, voidp params) { png_debug(1, "in png_write_png"); if (png_ptr == NULL || info_ptr == NULL) return; if ((info_ptr->valid & PNG_INFO_IDAT) == 0) { png_app_error(png_ptr, "no rows for png_write_image to write"); return; } /* Write the file header information. */ png_write_info(png_ptr, info_ptr); /* ------ these transformations don't touch the info structure ------- */ /* Invert monochrome pixels */ if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0) #ifdef PNG_WRITE_INVERT_SUPPORTED png_set_invert_mono(png_ptr); #else png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported"); #endif /* Shift the pixels up to a legal bit depth and fill in * as appropriate to correctly scale the image. */ if ((transforms & PNG_TRANSFORM_SHIFT) != 0) #ifdef PNG_WRITE_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 /* Pack pixels into bytes */ if ((transforms & PNG_TRANSFORM_PACKING) != 0) #ifdef PNG_WRITE_PACK_SUPPORTED png_set_packing(png_ptr); #else png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported"); #endif /* Swap location of alpha bytes from ARGB to RGBA */ if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0) #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED png_set_swap_alpha(png_ptr); #else png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported"); #endif /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into * RGB, note that the code expects the input color type to be G or RGB; no * alpha channel. */ if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER| PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0) { #ifdef PNG_WRITE_FILLER_SUPPORTED if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0) { if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0) png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported"); /* Continue if ignored - this is the pre-1.6.10 behavior */ png_set_filler(png_ptr, 0, PNG_FILLER_AFTER); } else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0) png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE); #else png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported"); #endif } /* Flip BGR pixels to RGB */ if ((transforms & PNG_TRANSFORM_BGR) != 0) #ifdef PNG_WRITE_BGR_SUPPORTED png_set_bgr(png_ptr); #else png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported"); #endif /* Swap bytes of 16-bit files to most significant byte first */ if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0) #ifdef PNG_WRITE_SWAP_SUPPORTED png_set_swap(png_ptr); #else png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported"); #endif /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */ if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0) #ifdef PNG_WRITE_PACKSWAP_SUPPORTED png_set_packswap(png_ptr); #else png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported"); #endif /* Invert the alpha channel from opacity to transparency */ if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0) #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED png_set_invert_alpha(png_ptr); #else png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported"); #endif /* ----------------------- end of transformations ------------------- */ /* Write the bits */ png_write_image(png_ptr, info_ptr->row_pointers); /* It is REQUIRED to call this to finish writing the rest of the file */ png_write_end(png_ptr, info_ptr); PNG_UNUSED(params) } #endif #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED /* Initialize the write structure - general purpose utility. */ static int png_image_write_init(png_imagep image) { png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image, png_safe_error, png_safe_warning); if (png_ptr != NULL) { png_infop info_ptr = png_create_info_struct(png_ptr); if (info_ptr != NULL) { png_controlp control = png_voidcast(png_controlp, png_malloc_warn(png_ptr, (sizeof *control))); if (control != NULL) { memset(control, 0, (sizeof *control)); control->png_ptr = png_ptr; control->info_ptr = info_ptr; control->for_write = 1; image->opaque = control; return 1; } /* Error clean up */ png_destroy_info_struct(png_ptr, &info_ptr); } png_destroy_write_struct(&png_ptr, NULL); } return png_image_error(image, "png_image_write_: out of memory"); } /* Arguments to png_image_write_main: */ typedef struct { /* Arguments: */ png_imagep image; png_const_voidp buffer; png_int_32 row_stride; png_const_voidp colormap; int convert_to_8bit; /* Local variables: */ png_const_voidp first_row; ptrdiff_t row_bytes; png_voidp local_row; /* Byte count for memory writing */ png_bytep memory; png_alloc_size_t memory_bytes; /* not used for STDIO */ png_alloc_size_t output_bytes; /* running total */ } png_image_write_control; /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to * do any necessary byte swapping. The component order is defined by the * png_image format value. */ static int png_write_image_16bit(png_voidp argument) { png_image_write_control *display = png_voidcast(png_image_write_control*, argument); png_imagep image = display->image; png_structrp png_ptr = image->opaque->png_ptr; png_const_uint_16p input_row = png_voidcast(png_const_uint_16p, display->first_row); png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row); png_uint_16p row_end; unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1; int aindex = 0; png_uint_32 y = image->height; if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0) { # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0) { aindex = -1; ++input_row; /* To point to the first component */ ++output_row; } else aindex = (int)channels; # else aindex = (int)channels; # endif } else png_error(png_ptr, "png_write_image: internal call error"); /* Work out the output row end and count over this, note that the increment * above to 'row' means that row_end can actually be beyond the end of the * row; this is correct. */ row_end = output_row + image->width * (channels+1); for (; y > 0; --y) { png_const_uint_16p in_ptr = input_row; png_uint_16p out_ptr = output_row; while (out_ptr < row_end) { png_uint_16 alpha = in_ptr[aindex]; png_uint_32 reciprocal = 0; int c; out_ptr[aindex] = alpha; /* Calculate a reciprocal. The correct calculation is simply * component/alpha*65535 << 15. (I.e. 15 bits of precision); this * allows correct rounding by adding .5 before the shift. 'reciprocal' * is only initialized when required. */ if (alpha > 0 && alpha < 65535) reciprocal = ((0xffff<<15)+(alpha>>1))/alpha; c = (int)channels; do /* always at least one channel */ { png_uint_16 component = *in_ptr++; /* The following gives 65535 for an alpha of 0, which is fine, * otherwise if 0/0 is represented as some other value there is more * likely to be a discontinuity which will probably damage * compression when moving from a fully transparent area to a * nearly transparent one. (The assumption here is that opaque * areas tend not to be 0 intensity.) */ if (component >= alpha) component = 65535; /* component<alpha, so component/alpha is less than one and * component*reciprocal is less than 2^31. */ else if (component > 0 && alpha < 65535) { png_uint_32 calc = component * reciprocal; calc += 16384; /* round to nearest */ component = (png_uint_16)(calc >> 15); } *out_ptr++ = component; } while (--c > 0); /* Skip to next component (skip the intervening alpha channel) */ ++in_ptr; ++out_ptr; } png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row)); input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16)); } return 1; } /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel * is present it must be removed from the components, the components are then * written in sRGB encoding. No components are added or removed. * * Calculate an alpha reciprocal to reverse pre-multiplication. As above the * calculation can be done to 15 bits of accuracy; however, the output needs to * be scaled in the range 0..255*65535, so include that scaling here. */ # define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+((alpha)>>1))/(alpha)) static png_byte png_unpremultiply(png_uint_32 component, png_uint_32 alpha, png_uint_32 reciprocal/*from the above macro*/) { /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0 * is represented as some other value there is more likely to be a * discontinuity which will probably damage compression when moving from a * fully transparent area to a nearly transparent one. (The assumption here * is that opaque areas tend not to be 0 intensity.) * * There is a rounding problem here; if alpha is less than 128 it will end up * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the * output change for this too. */ if (component >= alpha || alpha < 128) return 255; /* component<alpha, so component/alpha is less than one and * component*reciprocal is less than 2^31. */ else if (component > 0) { /* The test is that alpha/257 (rounded) is less than 255, the first value * that becomes 255 is 65407. * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore, * be exact!) [Could also test reciprocal != 0] */ if (alpha < 65407) { component *= reciprocal; component += 64; /* round to nearest */ component >>= 7; } else component *= 255; /* Convert the component to sRGB. */ return (png_byte)PNG_sRGB_FROM_LINEAR(component); } else return 0; } static int png_write_image_8bit(png_voidp argument) { png_image_write_control *display = png_voidcast(png_image_write_control*, argument); png_imagep image = display->image; png_structrp png_ptr = image->opaque->png_ptr; png_const_uint_16p input_row = png_voidcast(png_const_uint_16p, display->first_row); png_bytep output_row = png_voidcast(png_bytep, display->local_row); png_uint_32 y = image->height; unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1; if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0) { png_bytep row_end; int aindex; # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0) { aindex = -1; ++input_row; /* To point to the first component */ ++output_row; } else # endif aindex = (int)channels; /* Use row_end in place of a loop counter: */ row_end = output_row + image->width * (channels+1); for (; y > 0; --y) { png_const_uint_16p in_ptr = input_row; png_bytep out_ptr = output_row; while (out_ptr < row_end) { png_uint_16 alpha = in_ptr[aindex]; png_byte alphabyte = (png_byte)PNG_DIV257(alpha); png_uint_32 reciprocal = 0; int c; /* Scale and write the alpha channel. */ out_ptr[aindex] = alphabyte; if (alphabyte > 0 && alphabyte < 255) reciprocal = UNP_RECIPROCAL(alpha); c = (int)channels; do /* always at least one channel */ *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal); while (--c > 0); /* Skip to next component (skip the intervening alpha channel) */ ++in_ptr; ++out_ptr; } /* while out_ptr < row_end */ png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row)); input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16)); } /* while y */ } else { /* No alpha channel, so the row_end really is the end of the row and it * is sufficient to loop over the components one by one. */ png_bytep row_end = output_row + image->width * channels; for (; y > 0; --y) { png_const_uint_16p in_ptr = input_row; png_bytep out_ptr = output_row; while (out_ptr < row_end) { png_uint_32 component = *in_ptr++; component *= 255; *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component); } png_write_row(png_ptr, output_row); input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16)); } } return 1; } static void png_image_set_PLTE(png_image_write_control *display) { png_imagep image = display->image; const void *cmap = display->colormap; int entries = image->colormap_entries > 256 ? 256 : (int)image->colormap_entries; /* NOTE: the caller must check for cmap != NULL and entries != 0 */ png_uint_32 format = image->format; unsigned int channels = PNG_IMAGE_SAMPLE_CHANNELS(format); # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\ defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED) int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0; # else # define afirst 0 # endif # ifdef PNG_FORMAT_BGR_SUPPORTED int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0; # else # define bgr 0 # endif int i, num_trans; png_color palette[256]; png_byte tRNS[256]; memset(tRNS, 255, (sizeof tRNS)); memset(palette, 0, (sizeof palette)); for (i=num_trans=0; i<entries; ++i) { /* This gets automatically converted to sRGB with reversal of the * pre-multiplication if the color-map has an alpha channel. */ if ((format & PNG_FORMAT_FLAG_LINEAR) != 0) { png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap); entry += (unsigned int)i * channels; if ((channels & 1) != 0) /* no alpha */ { if (channels >= 3) /* RGB */ { palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 * entry[(2 ^ bgr)]); palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 * entry[1]); palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 * entry[bgr]); } else /* Gray */ palette[i].blue = palette[i].red = palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry); } else /* alpha */ { png_uint_16 alpha = entry[afirst ? 0 : channels-1]; png_byte alphabyte = (png_byte)PNG_DIV257(alpha); png_uint_32 reciprocal = 0; /* Calculate a reciprocal, as in the png_write_image_8bit code above * this is designed to produce a value scaled to 255*65535 when * divided by 128 (i.e. asr 7). */ if (alphabyte > 0 && alphabyte < 255) reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha; tRNS[i] = alphabyte; if (alphabyte < 255) num_trans = i+1; if (channels >= 3) /* RGB */ { palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)], alpha, reciprocal); palette[i].green = png_unpremultiply(entry[afirst + 1], alpha, reciprocal); palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha, reciprocal); } else /* gray */ palette[i].blue = palette[i].red = palette[i].green = png_unpremultiply(entry[afirst], alpha, reciprocal); } } else /* Color-map has sRGB values */ { png_const_bytep entry = png_voidcast(png_const_bytep, cmap); entry += (unsigned int)i * channels; switch (channels) { case 4: tRNS[i] = entry[afirst ? 0 : 3]; if (tRNS[i] < 255) num_trans = i+1; /* FALLTHROUGH */ case 3: palette[i].blue = entry[afirst + (2 ^ bgr)]; palette[i].green = entry[afirst + 1]; palette[i].red = entry[afirst + bgr]; break; case 2: tRNS[i] = entry[1 ^ afirst]; if (tRNS[i] < 255) num_trans = i+1; /* FALLTHROUGH */ case 1: palette[i].blue = palette[i].red = palette[i].green = entry[afirst]; break; default: break; } } } # ifdef afirst # undef afirst # endif # ifdef bgr # undef bgr # endif png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette, entries); if (num_trans > 0) png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS, num_trans, NULL); image->colormap_entries = (png_uint_32)entries; } static int png_image_write_main(png_voidp argument) { png_image_write_control *display = png_voidcast(png_image_write_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; /* The following four ints are actually booleans */ int colormap = (format & PNG_FORMAT_FLAG_COLORMAP); int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */ int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA); int write_16bit = linear && (display->convert_to_8bit == 0); # ifdef PNG_BENIGN_ERRORS_SUPPORTED /* Make sure we error out on any bad situation */ png_set_benign_errors(png_ptr, 0/*error*/); # endif /* Default the 'row_stride' parameter if required, also check the row stride * and total image size to ensure that they are within the system limits. */ { unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format); if (image->width <= 0x7fffffffU/channels) /* no overflow */ { png_uint_32 check; png_uint_32 png_row_stride = image->width * channels; if (display->row_stride == 0) display->row_stride = (png_int_32)/*SAFE*/png_row_stride; if (display->row_stride < 0) check = (png_uint_32)(-display->row_stride); else check = (png_uint_32)display->row_stride; if (check >= png_row_stride) { /* Now check for overflow of the image buffer calculation; this * limits the whole image size to 32 bits for API compatibility with * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro. */ if (image->height > 0xffffffffU/png_row_stride) png_error(image->opaque->png_ptr, "memory image too large"); } else png_error(image->opaque->png_ptr, "supplied row stride too small"); } else png_error(image->opaque->png_ptr, "image row stride too large"); } /* Set the required transforms then write the rows in the correct order. */ if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0) { if (display->colormap != NULL && image->colormap_entries > 0) { png_uint_32 entries = image->colormap_entries; png_set_IHDR(png_ptr, info_ptr, image->width, image->height, entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)), PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); png_image_set_PLTE(display); } else png_error(image->opaque->png_ptr, "no color-map for color-mapped image"); } else png_set_IHDR(png_ptr, info_ptr, image->width, image->height, write_16bit ? 16 : 8, ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) + ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0), PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); /* Counter-intuitively the data transformations must be called *after* * png_write_info, not before as in the read code, but the 'set' functions * must still be called before. Just set the color space information, never * write an interlaced image. */ if (write_16bit != 0) { /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */ png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR); if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0) png_set_cHRM_fixed(png_ptr, info_ptr, /* color x y */ /* white */ 31270, 32900, /* red */ 64000, 33000, /* green */ 30000, 60000, /* blue */ 15000, 6000 ); } else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0) png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL); /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit * space must still be gamma encoded. */ else png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE); /* Write the file header. */ png_write_info(png_ptr, info_ptr); /* Now set up the data transformations (*after* the header is written), * remove the handled transformations from the 'format' flags for checking. * * First check for a little endian system if writing 16-bit files. */ if (write_16bit != 0) { png_uint_16 le = 0x0001; if ((*(png_const_bytep) & le) != 0) png_set_swap(png_ptr); } # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED if ((format & PNG_FORMAT_FLAG_BGR) != 0) { if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0) png_set_bgr(png_ptr); format &= ~PNG_FORMAT_FLAG_BGR; } # endif # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED if ((format & PNG_FORMAT_FLAG_AFIRST) != 0) { if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0) png_set_swap_alpha(png_ptr); format &= ~PNG_FORMAT_FLAG_AFIRST; } # endif /* If there are 16 or fewer color-map entries we wrote a lower bit depth * above, but the application data is still byte packed. */ if (colormap != 0 && image->colormap_entries <= 16) png_set_packing(png_ptr); /* That should have handled all (both) the transforms. */ if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR | PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0) png_error(png_ptr, "png_write_image: unsupported transformation"); { png_const_bytep row = png_voidcast(png_const_bytep, display->buffer); ptrdiff_t row_bytes = display->row_stride; if (linear != 0) row_bytes *= (sizeof (png_uint_16)); if (row_bytes < 0) row += (image->height-1) * (-row_bytes); display->first_row = row; display->row_bytes = row_bytes; } /* Apply 'fast' options if the flag is set. */ if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0) { png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS); /* NOTE: determined by experiment using pngstest, this reflects some * balance between the time to write the image once and the time to read * it about 50 times. The speed-up in pngstest was about 10-20% of the * total (user) time on a heavily loaded system. */ # ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED png_set_compression_level(png_ptr, 3); # endif } /* Check for the cases that currently require a pre-transform on the row * before it is written. This only applies when the input is 16-bit and * either there is an alpha channel or it is converted to 8-bit. */ if ((linear != 0 && alpha != 0 ) || (colormap == 0 && display->convert_to_8bit != 0)) { png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr))); int result; display->local_row = row; if (write_16bit != 0) result = png_safe_execute(image, png_write_image_16bit, display); else result = png_safe_execute(image, png_write_image_8bit, display); display->local_row = NULL; png_free(png_ptr, row); /* Skip the 'write_end' on error: */ if (result == 0) return 0; } /* Otherwise this is the case where the input is in a format currently * supported by the rest of the libpng write code; call it directly. */ else { png_const_bytep row = png_voidcast(png_const_bytep, display->first_row); ptrdiff_t row_bytes = display->row_bytes; png_uint_32 y = image->height; for (; y > 0; --y) { png_write_row(png_ptr, row); row += row_bytes; } } png_write_end(png_ptr, info_ptr); return 1; } static void (PNGCBAPI image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data, size_t size) { png_image_write_control *display = png_voidcast(png_image_write_control*, png_ptr->io_ptr/*backdoor: png_get_io_ptr(png_ptr)*/); png_alloc_size_t ob = display->output_bytes; /* Check for overflow; this should never happen: */ if (size <= ((png_alloc_size_t)-1) - ob) { /* I don't think libpng ever does this, but just in case: */ if (size > 0) { if (display->memory_bytes >= ob+size) /* writing */ memcpy(display->memory+ob, data, size); /* Always update the size: */ display->output_bytes = ob+size; } } else png_error(png_ptr, "png_image_write_to_memory: PNG too big"); } static void (PNGCBAPI image_memory_flush)(png_structp png_ptr) { PNG_UNUSED(png_ptr) } static int png_image_write_memory(png_voidp argument) { png_image_write_control *display = png_voidcast(png_image_write_control*, argument); /* The rest of the memory-specific init and write_main in an error protected * environment. This case needs to use callbacks for the write operations * since libpng has no built in support for writing to memory. */ png_set_write_fn(display->image->opaque->png_ptr, display/*io_ptr*/, image_memory_write, image_memory_flush); return png_image_write_main(display); } int PNGAPI png_image_write_to_memory(png_imagep image, void *memory, png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8bit, const void *buffer, png_int_32 row_stride, const void *colormap) { /* Write the image to the given buffer, or count the bytes if it is NULL */ if (image != NULL && image->version == PNG_IMAGE_VERSION) { if (memory_bytes != NULL && buffer != NULL) { /* This is to give the caller an easier error detection in the NULL * case and guard against uninitialized variable problems: */ if (memory == NULL) *memory_bytes = 0; if (png_image_write_init(image) != 0) { png_image_write_control display; int result; memset(&display, 0, (sizeof display)); display.image = image; display.buffer = buffer; display.row_stride = row_stride; display.colormap = colormap; display.convert_to_8bit = convert_to_8bit; display.memory = png_voidcast(png_bytep, memory); display.memory_bytes = *memory_bytes; display.output_bytes = 0; result = png_safe_execute(image, png_image_write_memory, &display); png_image_free(image); /* write_memory returns true even if we ran out of buffer. */ if (result) { /* On out-of-buffer this function returns '0' but still updates * memory_bytes: */ if (memory != NULL && display.output_bytes > *memory_bytes) result = 0; *memory_bytes = display.output_bytes; } return result; } else return 0; } else return png_image_error(image, "png_image_write_to_memory: invalid argument"); } else if (image != NULL) return png_image_error(image, "png_image_write_to_memory: incorrect PNG_IMAGE_VERSION"); else return 0; } #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED int PNGAPI png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit, const void *buffer, png_int_32 row_stride, const void *colormap) { /* Write the image to the given (FILE*). */ if (image != NULL && image->version == PNG_IMAGE_VERSION) { if (file != NULL && buffer != NULL) { if (png_image_write_init(image) != 0) { png_image_write_control display; int result; /* 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; memset(&display, 0, (sizeof display)); display.image = image; display.buffer = buffer; display.row_stride = row_stride; display.colormap = colormap; display.convert_to_8bit = convert_to_8bit; result = png_safe_execute(image, png_image_write_main, &display); png_image_free(image); return result; } else return 0; } else return png_image_error(image, "png_image_write_to_stdio: invalid argument"); } else if (image != NULL) return png_image_error(image, "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION"); else return 0; } int PNGAPI png_image_write_to_file(png_imagep image, const char *file_name, int convert_to_8bit, const void *buffer, png_int_32 row_stride, const void *colormap) { /* Write the image to the named file. */ if (image != NULL && image->version == PNG_IMAGE_VERSION) { if (file_name != NULL && buffer != NULL) { FILE *fp = fopen(file_name, "wb"); if (fp != NULL) { if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer, row_stride, colormap) != 0) { int error; /* from fflush/fclose */ /* Make sure the file is flushed correctly. */ if (fflush(fp) == 0 && ferror(fp) == 0) { if (fclose(fp) == 0) return 1; error = errno; /* from fclose */ } else { error = errno; /* from fflush or ferror */ (void)fclose(fp); } (void)remove(file_name); /* The image has already been cleaned up; this is just used to * set the error (because the original write succeeded). */ return png_image_error(image, strerror(error)); } else { /* Clean up: just the opened file. */ (void)fclose(fp); (void)remove(file_name); return 0; } } else return png_image_error(image, strerror(errno)); } else return png_image_error(image, "png_image_write_to_file: invalid argument"); } else if (image != NULL) return png_image_error(image, "png_image_write_to_file: incorrect PNG_IMAGE_VERSION"); else return 0; } #endif /* SIMPLIFIED_WRITE_STDIO */ #endif /* SIMPLIFIED_WRITE */ #endif /* WRITE */