/* pngwrite.c - general routines to write a PNG file * * Last changed in libpng 1.7.0 [(PENDING RELEASE)] * 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 */ #include "pngpriv.h" #if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) # include #endif #define PNG_SRC_FILE PNG_SRC_FILE_pngwrite #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_ 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_HAVE_IHDR) == 0) { int color_type = PNG_COLOR_TYPE_FROM_FORMAT(info_ptr->format); /* Write PNG signature; doesn't set PNG_HAVE_PNG_SIGNATURE if it has * already been written (or rather, if at least 3 bytes have already been * written; undocumented wackiness, it means the 'PNG' at the start can be * replace by, e.g. "FOO" or "BAR" or "MNG"). */ 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_app_error(png_ptr, "MNG features are not allowed in a PNG datastream"); /* Recovery: disable MNG features: */ png_ptr->mng_features_permitted = 0; } # endif /* MNG_FEATURES */ /* Write IHDR information. */ png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height, info_ptr->bit_depth, color_type, info_ptr->compression_type, info_ptr->filter_type, info_ptr->interlace_type); # ifdef PNG_WRITE_TRANSFORMS_SUPPORTED /* This are used for checking later on: */ png_ptr->info_format = info_ptr->format; # endif /* WRITE_TRANSFORMS */ /* This sets the flag that prevents re-entry to the 'before PLTE' case: */ affirm((png_ptr->mode & PNG_HAVE_IHDR) != 0); /* 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_WRITE_gAMA_SUPPORTED /* enables GAMMA */ 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) { /* This is the inverse of the test in png.c: */ affirm(info_ptr->colorspace.gamma >= 16 && info_ptr->colorspace.gamma <= 625000000); png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma); } # endif /* WRITE_gAMA */ /* 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 /* enables COLORSPACE, GAMMA */ if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 && (info_ptr->valid & PNG_INFO_iCCP) != 0) { # ifdef PNG_WRITE_sRGB_SUPPORTED /* The app must have supplied an sRGB iCCP profile (and one that * is recognized and therefore known to be correct) so we write * that profile, even though it increases the size of the PNG * significantly. A warning is reasonable: */ if ((info_ptr->valid & PNG_INFO_sRGB) != 0) png_app_warning(png_ptr, "profile matches sRGB but writing iCCP instead"); # endif /* WRITE_sRGB */ png_write_iCCP(png_ptr, info_ptr->iccp_name, info_ptr->iccp_profile); } # ifdef PNG_WRITE_sRGB_SUPPORTED else /* iCCP not written */ # endif /* WRITE_sRGB */ # endif /* WRITE_iCCP */ # ifdef PNG_WRITE_sRGB_SUPPORTED /* enables COLORSPACE, GAMMA */ 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 */ # ifdef PNG_WRITE_sBIT_SUPPORTED if ((info_ptr->valid & PNG_INFO_sBIT) != 0) png_write_sBIT(png_ptr, &(info_ptr->sig_bit), color_type); # endif /* WRITE_sBIT */ # ifdef PNG_WRITE_cHRM_SUPPORTED /* enables COLORSPACE */ 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 /* WRITE_cHRM */ # ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED /* The third arugment must encode only one bit, otherwise chunks will * be written twice because the test in write_unknown_chunks is * 'location & where'. */ write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR); # endif } else /* 1.7.0: flag multiple calls; previously ignored */ png_app_error(png_ptr, "png_write_info_before_PLTE called more than once"); } #ifdef PNG_WRITE_TEXT_SUPPORTED static void png_write_text(png_structrp png_ptr, png_const_inforp info_ptr) /* Text chunk helper */ { int i; /* Check to see if we need to write text chunks */ for (i = 0; i < info_ptr->num_text; i++) { png_debug2(2, "Writing 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); # else /* !WRITE_iTXT */ png_app_error(png_ptr, "Unable to write international text"); # endif /* !WRITE_iTXT */ /* 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; } /* 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); # else /* !WRITE_zTXT */ png_app_error(png_ptr, "Unable to write compressed text"); # endif /* !WRITE_zTXT */ /* Mark this chunk as written */ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR; } 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); # else /* !WRITE_tEXt */ /* Can't get here TODO: why not? */ png_app_error(png_ptr, "Unable to write uncompressed text"); # endif /* !WRITE_tEXt */ /* Mark this chunk as written */ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR; } } } #endif /* WRITE_TEXT */ void PNGAPI png_write_info(png_structrp png_ptr, png_const_inforp info_ptr) { png_debug(1, "in png_write_info"); if (png_ptr == NULL || info_ptr == NULL) return; if ((png_ptr->mode & (PNG_HAVE_PLTE+PNG_HAVE_IDAT)) != 0) { png_app_error(png_ptr, "late call to png_write_info"); return; } /* The app may do this for us, and in 1.7.0 multiple calls are flagged as an * application error, so this code must check: */ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) 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, info_ptr->num_palette); /* Validate the consistency of the PNG being produced; a palette must have * been written if a palette mapped PNG is to be valid: */ if ((png_ptr->mode & PNG_HAVE_PLTE) == 0 && png_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) { png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color), info_ptr->num_trans, PNG_COLOR_TYPE_FROM_FORMAT(info_ptr->format)); } # endif /* WRITE_tRNS */ # ifdef PNG_WRITE_bKGD_SUPPORTED if ((info_ptr->valid & PNG_INFO_bKGD) != 0) png_write_bKGD(png_ptr, &(info_ptr->background), PNG_COLOR_TYPE_FROM_FORMAT(info_ptr->format)); # endif /* WRITE_bKGD */ # 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 /* WRITE_hIST */ # 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 /* WRITE_oFFs */ # 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 /* WRITE_pCAL */ # ifdef PNG_WRITE_sCAL_SUPPORTED if ((info_ptr->valid & PNG_INFO_sCAL) != 0) png_write_sCAL_s(png_ptr, info_ptr->scal_unit, info_ptr->scal_s_width, info_ptr->scal_s_height); # endif /* WRITE_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 /* WRITE_pHYs */ # ifdef PNG_WRITE_tIME_SUPPORTED if ((info_ptr->valid & PNG_INFO_tIME) != 0) png_write_tIME(png_ptr, &(info_ptr->mod_time)); # endif /* WRITE_tIME */ # ifdef PNG_WRITE_sPLT_SUPPORTED if ((info_ptr->valid & PNG_INFO_sPLT) != 0) { int i; for (i = 0; i < info_ptr->splt_palettes_num; i++) png_write_sPLT(png_ptr, info_ptr->splt_palettes + i); } # endif /* WRITE_sPLT */ # ifdef PNG_WRITE_TEXT_SUPPORTED if (info_ptr->num_text > 0) png_write_text(png_ptr, info_ptr); # endif /* WRITE_TEXT */ # ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE); # endif /* WRITE_UNKNOWN_CHUNKS */ } /* 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_IHDR+PNG_HAVE_IDAT+PNG_AFTER_IDAT+PNG_HAVE_IEND)) != (PNG_HAVE_IHDR+PNG_HAVE_IDAT+PNG_AFTER_IDAT)) { /* Out of place png_write_end: */ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) png_error(png_ptr, "Missing call to png_write_info"); else if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 && png_ptr->zowner == 0) { /* TODO: write unknown IDAT here, for the moment allow the app to write * IDAT then call write_end: */ png_app_error(png_ptr, "No IDATs written into file"); png_ptr->mode |= PNG_HAVE_IDAT+PNG_AFTER_IDAT; } else if ((png_ptr->mode & PNG_AFTER_IDAT) == 0) { affirm(png_ptr->zowner == png_IDAT); png_error(png_ptr, "incomplete PNG image"); /* unrecoverable */ } else if ((png_ptr->mode & PNG_HAVE_IEND) != 0) { png_app_error(png_ptr, "multiple calls to png_write_end"); return; } else impossible("not reached"); } /* And double check that the image rows were all written; this is actually * a harmless error on an interlaced image because the image rows with * data were all passed in or the above check would not work. * * Don't do this if the IDAT came from unknowns (TBD) or the app, above. * * The check depends on the precise logic in png_write_finish_row. */ else if (png_ptr->interlaced ? png_ptr->pass != PNG_INTERLACE_ADAM7_PASSES : png_ptr->row_number != png_ptr->height) png_app_error(png_ptr, "png_write_row not called to last row"); /* See if user wants us to write information chunks */ if (info_ptr != NULL) { # ifdef PNG_WRITE_tIME_SUPPORTED /* Check to see if user has supplied a time chunk */ if ((info_ptr->valid & PNG_INFO_tIME) != 0) png_write_tIME(png_ptr, &(info_ptr->mod_time)); # endif # ifdef PNG_WRITE_TEXT_SUPPORTED if (info_ptr->num_text > 0) png_write_text(png_ptr, info_ptr); # endif /* WRITE_TEXT */ # ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT); # endif } /* 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, PNG_CONST struct tm * ttime) { png_debug(1, "in png_convert_from_struct_tm"); ptime->year = png_check_u16(0/*TODO: fixme*/, 1900 + ttime->tm_year); ptime->month = png_check_byte(0/*TODO: fixme*/, ttime->tm_mon + 1); ptime->day = png_check_byte(0/*TODO: fixme*/, ttime->tm_mday); ptime->hour = png_check_byte(0/*TODO: fixme*/, ttime->tm_hour); ptime->minute = png_check_byte(0/*TODO: fixme*/, ttime->tm_min); ptime->second = png_check_byte(0/*TODO: fixme*/, 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); 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 } 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_debug(1, "in png_write_rows"); if (png_ptr == NULL || row == NULL) return; /* Loop through the rows */ while (num_rows-- > 0) png_write_row(png_ptr, *row++); } /* 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) { int num_pass; /* pass variables */ if (png_ptr == NULL || image == 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; if (png_ptr->interlaced) { png_app_error(png_ptr, "no interlace support"); return; } #endif /* Loop through passes */ while (num_pass-- > 0) { png_bytepp rp = image; /* points to current row */ png_uint_32 num_rows = png_ptr->height; /* Loop through image */ while (num_rows-- > 0) png_write_row(png_ptr, *rp++); } } /* Called to advance to the next row. A row may not have been output when * libpng handles the interlace passes because the app hands libpng every image * row for every pass. * * This function also writes the current row, if the pointer to the bytes is * non-NULL, and does so with the appropriate 'flush' argument to zlib. */ static void png_write_finish_row(png_structrp png_ptr, png_byte filter_byte, png_const_bytep row, png_alloc_size_t row_bytes) { const png_uint_32 height = png_ptr->height; png_uint_32 row_number = png_ptr->row_number; int flush = Z_NO_FLUSH; png_debug(1, "in png_write_finish_row"); if (png_ptr->interlaced) { unsigned int pass = png_ptr->pass; # ifdef PNG_WRITE_INTERLACING_SUPPORTED if (png_ptr->do_interlace) { /* libpng is doing the de-interlace. */ /* Z_FINISH must be set on the last row present in the image, not * the actual last row. * * NOTE: this means that the application need not call libpng all * the way to the end of the image, but this is double checked * below in png_write_end where png_ptr->pass is checked. */ if (pass == PNG_LAST_PASS(png_ptr->width, height) && PNG_LAST_PASS_ROW(row_number, pass, height) && PNG_ROW_IN_INTERLACE_PASS(row_number, pass)) flush = Z_FINISH; /* end of image */ if (++row_number == height) { ++pass; row_number = 0; png_ptr->pass = pass & 0x7; } } /* libpng doing interlace */ else /* app is doing the interlacing */ # endif /* WRITE_INTERLACING */ /* The application has to hand us interlaced rows. In this case * row_number is the row number in the pass (this is not the * behavior in the read code, where it is always the row number in * the image.) * * Note that for any image row 0 of pass 0 is always present, so the * check after the 'if' is not required at the start. */ { affirm(row != NULL); if (++row_number == PNG_PASS_ROWS(height, pass)) { const png_uint_32 width = png_ptr->width; /* Next pass, but it may not be present because of the width. */ row_number = 0; for (;;) { if (++pass == PNG_INTERLACE_ADAM7_PASSES) { flush = Z_FINISH; break; /* end of image */ } if (PNG_PASS_IN_IMAGE(width, height, pass)) break; } png_ptr->pass = pass & 0x7; } /* end of pass */ } /* app doing interlace */ } /* writing an interlaced PNG */ else /* PNG not interlaced */ if (++row_number == height) flush = Z_FINISH; png_ptr->row_number = row_number; if (row != NULL) { png_compress_IDAT(png_ptr, &filter_byte, 1, Z_NO_FLUSH); png_compress_IDAT(png_ptr, row, row_bytes, flush); # ifdef PNG_WRITE_FLUSH_SUPPORTED if (flush == Z_NO_FLUSH && ++png_ptr->flush_rows >= png_ptr->flush_dist && png_ptr->flush_dist > 0) png_write_flush(png_ptr); # endif /* WRITE_FLUSH */ } /* The calculations above should ensure that Z_FINISH is set on the last row * written, the following rows are empty pass rows, so the deflate stream * should already have been closed: */ else affirm(flush == Z_NO_FLUSH || png_ptr->zowner == 0); } /* Called by user to write a row of image data */ void PNGAPI png_write_row(png_structrp png_ptr, png_const_bytep row) { png_uint_32 row_number, row_width; unsigned int pass; # ifdef PNG_WRITE_FILTER_SUPPORTED int last_pass_row, first_pass_row; # endif if (png_ptr == NULL) return; png_debug2(1, "in png_write_row (row %u, pass %d)", png_ptr->row_number, png_ptr->pass); row_number = png_ptr->row_number; row_width = png_ptr->width; pass = png_ptr->pass; /* Unlike the read code initialization happens automatically: */ if (row_number == 0 && pass == 0) { png_init_row_info(png_ptr); /* doesn't change row/pass/width */ /* If the app takes a png_info from a read operation and if the app has * performed transforms on the data the png_info can contain IHDR * information that cannot be represented in PNG. The code that writes * the IHDR takes the color type from the png_info::format. The app adds * transforms, before or after writing the IHDR, then the IHDR color_type * stored in png_struct::color_type is used in png_init_row_info above to * work out the actual row format. * * Prior to 1.7.0 this was not verified (there was no easy way to do so). * Now we can check it here, however this is an: * * API CHANGE: in 1.7.0 an error may be flagged against bogus info_struct * formats even though the app had removed them itself. It's just a * warning at present. */ # ifdef PNG_WRITE_TRANSFORMS_SUPPORTED /* The test is that either the row_format produced by the write * transforms exactly matches that in the original info_struct::format * or that the info_struct::format was a simple mapping of the * color_type that ended up in the IHDR: */ if (png_ptr->row_format != png_ptr->info_format && PNG_FORMAT_FROM_COLOR_TYPE(png_ptr->color_type) != png_ptr->info_format) png_app_warning(png_ptr, "info_struct format does not match IHDR"); # endif /* WRITE_TRANSFORMS */ } else if (row_number >= png_ptr->height || pass >= PNG_INTERLACE_ADAM7_PASSES) png_error(png_ptr, "Too many calls to png_write_row"); /* If interlaced and not interested in row, return. Note that the * assumption here, as in the read code, is that if the app wants to write an * interlaced image when libpng does not support WRITE_INTERLACING the app * will only provide the rows actually in the pass. */ if (png_ptr->interlaced) { # ifdef PNG_WRITE_INTERLACING_SUPPORTED if (png_ptr->do_interlace) { /* libpng is doing the de-interlace. */ if (!PNG_ROW_IN_INTERLACE_PASS(row_number, pass) || PNG_PASS_COLS(row_width, pass) == 0) { /* Not in the pass; advance to the next row. Notice that because * the app is expected to call us once for every image row in * every pass it is sufficient to just add one to row_number * here. */ png_write_finish_row(png_ptr, 0, NULL, 0); return; } /* Else: this row must be output, row_number is the row in the * image. */ last_pass_row = PNG_LAST_PASS_ROW(row_number, pass, png_ptr->height); first_pass_row = row_number == PNG_PASS_START_ROW(pass); debug(row_number >= PNG_PASS_START_ROW(pass)); } else /* app is doing the interlacing */ # endif /* WRITE_INTERLACING */ { /* The interlaced rows come from the application and they have the * correct width, row_number is the row number in the pass, not the * number of the corresponding (expanded) image row. */ row_width = PNG_PASS_COLS(row_width, pass); # ifdef PNG_WRITE_FILTER_SUPPORTED last_pass_row = row_number+1 >= PNG_PASS_ROWS(png_ptr->height, pass); first_pass_row = row_number == 0; # endif /* WRITE_INTERLACING */ } } /* writing an interlaced PNG */ # ifdef PNG_WRITE_FILTER_SUPPORTED else /* not an interlaced PNG */ { last_pass_row = row_number+1 >= png_ptr->height; first_pass_row = row_number == 0; } # endif /* WRITE_INTERLACING */ /* 1.7.0: pretty much everything except the PNG row filter happens under the * control of the transform code. * * png_struct::row_format is the *input* row format. During the transforms * the png_transform_control::{sp,dp} pointers are used in the normal fashion * with dp initially set to png_struct::row_buffer. * * After the transforms if there is no filtering to be done (WRITE_FILTER is * not supported) 'sp' is written directly; it may be png_struct::row_buffer * or it may be the original 'row' parameter to this routine. There is no * need to save the transformed (PNG format) row. * * If there is filtering to be done then either the original row or * png_transform_control::sp is filtered against the previous row, which is * in png_struct::alt_buffer, the result is written with the appropriate * filter byte and then the original row or png_transform_control::sp is * saved to png_struct::alt_buffer. * * Thus there are four control flow possibilities depending on the pair of * compile time flags [WRITE_TRANSFORM_MECH,WRITE_FILTER]. The simplest * write code, which requires no internal buffer, arises when both are * compiled out. alt_buffer is only required if WRITE_FILTER is supported * and row_buffer is required when either are supported. */ { png_byte filter_byte; unsigned int output_bpp; /* bits per pixel */ png_const_bytep output_row; png_alloc_size_t output_bytes; # ifdef PNG_TRANSFORM_MECH_SUPPORTED if (png_ptr->transform_list != NULL) /* else no transforms */ { png_transform_control tc; /* The initial values are the memory format, this was worked out in * png_init_row_info above. */ memset(&tc, 0, sizeof tc); tc.png_ptr = png_ptr; tc.sp = row; tc.dp = png_ptr->row_buffer; if (tc.dp == NULL) png_ptr->row_buffer = png_voidcast(png_bytep, tc.dp = png_malloc(png_ptr, png_ptr->row_allocated_bytes)); tc.width = row_width; /* width of interlaced row */ tc.format = png_ptr->row_format; tc.range = png_ptr->row_range; tc.bit_depth = png_ptr->row_bit_depth; /* tc.init == 0 */ /* tc.caching: not used */ /* tc.palette: not used */ /* Run the list. */ png_run_transform_list_backwards(png_ptr, &tc); /* Make sure the format that resulted is compatible with PNG: */ affirm((tc.format & PNG_BIC_MASK(PNG_FORMAT_FLAG_ALPHA + PNG_FORMAT_FLAG_COLOR + PNG_FORMAT_FLAG_LINEAR + PNG_FORMAT_FLAG_COLORMAP)) == 0); /* Now we must have the PNG format from the IHDR: */ affirm(png_ptr->bit_depth == tc.bit_depth && png_ptr->color_type == PNG_COLOR_TYPE_FROM_FORMAT(tc.format)); /* If libpng is handling the interlacing the row width must now * match the width required for this pass. */ affirm(tc.width == (!png_ptr->do_interlace ? row_width : PNG_PASS_COLS(row_width, pass))); row_width = tc.width; output_row = png_voidcast(png_const_bytep, tc.sp); } else /* no transforms */ # endif /* TRANSFORM_MECH */ output_row = row; output_bpp = PNG_PIXEL_DEPTH(*png_ptr); output_bytes = PNG_ROWBYTES(output_bpp, row_width); # ifdef PNG_WRITE_FILTER_SUPPORTED { png_const_bytep unfiltered_row = output_row; png_bytep alt_buffer = png_ptr->alt_buffer; /* If necessary find an appropriate filter and apply it to get the * filtered row. The function may return the original argument, it * fills in 'filter_byte' appropriately. */ if (png_ptr->next_filter != PNG_FILTER_NONE) output_row = png_write_filter_row(png_ptr, output_row, first_pass_row, alt_buffer, output_bytes, (output_bpp+7)>>3 /* bytes per pixel */, &filter_byte); else filter_byte = PNG_FILTER_VALUE_NONE; /* If the available filters require it, or ever did (as evidenced by * the presence of 'alt_buffer', store the unfiltered row in * alt_buffer. Note that this does not happen on the last row of a * pass, or the image. */ if (!last_pass_row && (alt_buffer != NULL || (png_ptr->next_filter & (PNG_FILTER_UP+PNG_FILTER_AVG+PNG_FILTER_PAETH)) != 0)) { if (unfiltered_row == row) /* Must be copied */ { if (alt_buffer == NULL) png_ptr->alt_buffer = alt_buffer = png_voidcast(png_bytep, png_malloc(png_ptr, png_ptr->row_allocated_bytes)); memcpy(alt_buffer, unfiltered_row, output_bytes); } else /* Can be swapped */ { png_bytep tmp = png_ptr->row_buffer; affirm(unfiltered_row == tmp); png_ptr->row_buffer = alt_buffer; /* may be NULL */ png_ptr->alt_buffer = tmp; } } } # else /* !WRITE_FILTER: no previous row to store */ filter_byte = PNG_FILTER_VALUE_NONE; # endif /* !WRITE_FILTER */ png_write_finish_row(png_ptr, filter_byte, output_row, output_bytes); } /* API CHANGE: 1.7.0: this is now called after png_struct::row_number and * png_struct::pass have been updated and, at the end of the image, after the * deflate stream has been closed. The order of the call with respect to the * flush operation has also changed. The callback can't discover any of this * unless it relies on the write callbacks to find the row data, and that was * never predictable. * * * TODO: API CHANGE: pass the row bytes to this function, it would be more * useful. */ if (png_ptr->write_row_fn != NULL) (*(png_ptr->write_row_fn))(png_ptr, row_number, 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 : 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; /* Before the start of the IDAT and after the end of the image zowner will be * something other than png_IDAT: */ if (png_ptr->zowner == png_IDAT) { 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->zstream.state != NULL) { int ret = deflateEnd(&png_ptr->zstream); if (ret != Z_OK) { png_zstream_error(png_ptr, ret); png_warning(png_ptr, png_ptr->zstream.msg); } } /* 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_buffer); png_ptr->row_buffer = NULL; #ifdef PNG_WRITE_FILTER_SUPPORTED png_free(png_ptr, png_ptr->alt_buffer); png_ptr->alt_buffer = NULL; png_free(png_ptr, png_ptr->write_row[0]); png_ptr->write_row[0] = NULL; png_free(png_ptr, png_ptr->write_row[1]); png_ptr->write_row[1] = NULL; #endif #ifdef PNG_TRANSFORM_MECH_SUPPORTED png_transform_free(png_ptr, &png_ptr->transform_list); #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); } } } #ifdef PNG_WRITE_FILTER_SUPPORTED /* 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; if (png_ptr->read_struct) { png_app_error(png_ptr, "png_set_filter: cannot be used when reading"); return; } if (method != png_ptr->filter_method) { png_app_error(png_ptr, "png_set_filter: method does not match IHDR"); return; } /* PNG and MNG use the same base adaptive filter types: */ if (method != PNG_FILTER_TYPE_BASE && method != PNG_INTRAPIXEL_DIFFERENCING) { png_app_error(png_ptr, "png_set_filter: unsupported method"); return; } /* Notice that PNG_NO_FILTERS is 0 and passes this test; this is OK * because filters then gets set to PNG_FILTER_NONE, as is required. */ if (filters < PNG_FILTER_VALUE_LAST) filters = 0x08 << filters; else if ((filters & PNG_BIC_MASK(PNG_ALL_FILTERS)) != 0) { png_app_error(png_ptr, "png_set_filter: invalid filters mask/value"); /* Prior to 1.7.0 this ignored the error and just used the bits that are * present, now it does nothing; this seems a lot safer. */ return; } /* Finally store the value. */ png_ptr->next_filter = PNG_BYTE(filters); } #endif /* WRITE_FILTER */ #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* GRR 970116 */ /* Legacy API that weighted the filter metric by the number of times it had been * used before. */ #ifdef PNG_FLOATING_POINT_SUPPORTED PNG_FUNCTION(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_DEPRECATED) { png_app_warning(png_ptr, "weighted filter heuristics not implemented"); PNG_UNUSED(heuristic_method) PNG_UNUSED(num_weights) PNG_UNUSED(filter_weights) PNG_UNUSED(filter_costs) } #endif /* FLOATING_POINT */ #ifdef PNG_FIXED_POINT_SUPPORTED PNG_FUNCTION(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_DEPRECATED) { png_app_warning(png_ptr, "weighted filter heuristics not implemented"); 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) { 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) { 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) { if (png_ptr == NULL) return; png_ptr->write_row_fn = write_row_fn; } #ifdef PNG_WRITE_PNG_SUPPORTED void PNGAPI png_write_png(png_structrp png_ptr, png_inforp info_ptr, int transforms, voidp params) { 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, 2, 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 /* WRITE_PNG */ #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED #ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */ /* 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; } 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; const 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 # endif aindex = channels; } 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); while (y-- > 0) { png_const_uint_16p in_ptr = input_row; png_uint_16p out_ptr = output_row; while (out_ptr < row_end) { const 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 = 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 0 && alpha < 65535) { png_uint_32 calc = component * reciprocal; calc += 16384; /* round to nearest */ component = png_check_u16(png_ptr, 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 += 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_const_structrp png_ptr, 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 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_sRGB_FROM_LINEAR(png_ptr, component); } else return 0; PNG_UNUSEDRC(png_ptr) } 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; const 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 = channels; /* Use row_end in place of a loop counter: */ row_end = output_row + image->width * (channels+1); while (y-- > 0) { 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_check_byte(png_ptr, 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 = channels; do /* always at least one channel */ *out_ptr++ = png_unpremultiply(png_ptr, *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 += 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; while (y-- > 0) { 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_sRGB_FROM_LINEAR(png_ptr, component); } png_write_row(png_ptr, output_row); input_row += display->row_bytes/(sizeof (png_uint_16)); } } return 1; } static void png_image_set_PLTE(png_image_write_control *display) { const png_imagep image = display->image; const void *cmap = display->colormap; const int entries = image->colormap_entries > 256 ? 256 : (int)image->colormap_entries; /* NOTE: the caller must check for cmap != NULL and entries != 0 */ const png_uint_32 format = image->format; const int channels = PNG_IMAGE_SAMPLE_CHANNELS(format); # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\ defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED) const int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0; # else # define afirst 0 # endif # ifdef PNG_FORMAT_BGR_SUPPORTED const 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= 3) /* RGB */ { palette[i].blue = PNG_sRGB_FROM_LINEAR( display->image->opaque->png_ptr, 255 * entry[(2 ^ bgr)]); palette[i].green = PNG_sRGB_FROM_LINEAR( display->image->opaque->png_ptr, 255 * entry[1]); palette[i].red = PNG_sRGB_FROM_LINEAR( display->image->opaque->png_ptr, 255 * entry[bgr]); } else /* Gray */ palette[i].blue = palette[i].red = palette[i].green = PNG_sRGB_FROM_LINEAR(display->image->opaque->png_ptr, 255 * *entry); } else /* alpha */ { png_uint_16 alpha = entry[afirst ? 0 : channels-1]; png_byte alphabyte = png_check_byte( display->image->opaque->png_ptr, 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( display->image->opaque->png_ptr, entry[afirst + (2 ^ bgr)], alpha, reciprocal); palette[i].green = png_unpremultiply( display->image->opaque->png_ptr, entry[afirst + 1], alpha, reciprocal); palette[i].red = png_unpremultiply( display->image->opaque->png_ptr, entry[afirst + bgr], alpha, reciprocal); } else /* gray */ palette[i].blue = palette[i].red = palette[i].green = png_unpremultiply(display->image->opaque->png_ptr, entry[afirst], alpha, reciprocal); } } else /* Color-map has sRGB values */ { png_const_bytep entry = png_voidcast(png_const_bytep, cmap); entry += i * channels; switch (channels) { case 4: tRNS[i] = entry[afirst ? 0 : 3]; if (tRNS[i] < 255) num_trans = i+1; /* FALL THROUGH */ 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; /* FALL THROUGH */ 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 = 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 && !colormap && (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. */ if (display->row_stride == 0) display->row_stride = PNG_IMAGE_ROW_STRIDE(*image); /* 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_CONST 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_BIC_MASK(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_BIC_MASK(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_BIC_MASK(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) { # ifdef PNG_WRITE_FILTER_SUPPORTED png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS); # endif /* WRITE_FILTER */ /* 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 /* WRITE_CUSTOMIZE_COMPRESSION */ } /* 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; while (y-- > 0) { png_write_row(png_ptr, row); row += row_bytes; } } png_write_end(png_ptr, info_ptr); return 1; } 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) { if (png_image_write_init(image) != 0 && png_image_init_io(image, file) != 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; 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) { 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 /* STDIO */ #endif /* SIMPLIFIED_WRITE */ #endif /* WRITE */