/* pngwrite.c - general routines to write a PNG file * * Last changed in libpng 1.7.0 [(PENDING RELEASE)] * Copyright (c) 1998-2002,2004,2006-2016 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" #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED # include #endif /* SIMPLIFIED_WRITE_STDIO */ #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 png_write_chunk(png_ptr, up->name, up->data, up->size); } } } #endif /* WRITE_UNKNOWN_CHUNKS */ #ifdef PNG_WRITE_TEXT_SUPPORTED static void png_write_text(png_structrp png_ptr, png_const_inforp info_ptr, png_byte where) /* 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); /* Text chunks are written at info_ptr->text[i].location, skip the chunk * if we are not writing at that location: */ if ((info_ptr->text[i].location & where) == 0U) continue; switch (info_ptr->text[i].compression) { case PNG_ITXT_COMPRESSION_NONE: case PNG_ITXT_COMPRESSION_zTXt: # 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 */ break; case 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 */ break; case 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 */ break; default: /* This is an internal error because the libpng checking should * never manage to set any 'compression' except the above values. */ impossible("invalid text compression"); } /* The chunk was written, record where. This allows the location to have * multiple bits set; the first successful write freezes the location. */ info_ptr->text[i].location = where; } } #endif /* WRITE_TEXT */ /* 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_tIME_SUPPORTED if ((info_ptr->valid & PNG_INFO_tIME) != 0 && (info_ptr->time_location & PNG_HAVE_IHDR) != 0) png_write_tIME(png_ptr, &(info_ptr->mod_time)); # endif /* WRITE_tIME */ # 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_TEXT_SUPPORTED if (info_ptr->num_text > 0) png_write_text(png_ptr, info_ptr, PNG_HAVE_IHDR); # endif /* WRITE_TEXT */ # 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"); } 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"); /* But always set the mode flag because without this we don't know when to * write the post-palette text or unknown chunks. */ png_ptr->mode |= PNG_HAVE_PLTE; # 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 && (info_ptr->time_location & PNG_HAVE_PLTE) != 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, PNG_HAVE_PLTE); # 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_row. */ else if (png_ptr->pass != 7U) png_app_error(png_ptr, "png_write_row not called to last row"); else debug(png_ptr->row_number == 0U); /* 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 && (info_ptr->time_location & PNG_AFTER_IDAT) != 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, PNG_AFTER_IDAT); # 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 if (png_ptr->output_flush_fn != NULL) png_ptr->output_flush_fn(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) { # ifdef PNG_BENIGN_ERRORS_SUPPORTED # if !PNG_RELEASE_BUILD /* Always quit on error prior to release */ png_ptr->benign_error_action = PNG_ERROR; png_ptr->app_warning_action = PNG_WARN; png_ptr->app_error_action = PNG_ERROR; # else /* RELEASE_BUILD */ /* Allow benign errors on write, subject to app control. */ # ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED png_ptr->benign_error_action = PNG_WARN; png_ptr->app_error_action = PNG_WARN; png_ptr->app_warning_action = PNG_WARN; # else /* !BENIGN_WRITE_ERRORS */ /* libpng build without benign error support; the application * author has to be assumed to be correct, so: */ png_ptr->benign_error_action = PNG_ERROR; png_ptr->app_warning_action = PNG_WARN; png_ptr->app_error_action = PNG_ERROR; # endif /* !BENIGN_WRITE_ERRORS */ # endif /* RELEASE_BUILD */ # endif /* BENIGN_ERRORS */ } return png_ptr; } #if defined(PNG_WRITE_INTERLACING_SUPPORTED) ||\ defined(PNG_WRITE_TRANSFORMS_SUPPORTED) static void write_row_buffered(png_structrp png_ptr, png_const_bytep row, unsigned int row_info_flags, void (*copy_fn)(png_const_structrp png_ptr, png_bytep row_buffer, png_const_bytep row, png_uint_32 x, unsigned int count, unsigned int p), unsigned int copy_parameter) { unsigned int max_pixels = png_max_pixel_block(png_ptr); const unsigned int pass = png_ptr->pass; const png_uint_32 width = png_ptr->interlaced == PNG_INTERLACE_NONE ? png_ptr->width : PNG_PASS_COLS(png_ptr->width, pass); png_uint_32 x; png_byte prev_pixels[4*2*2]; /* 2 pixels up to 4 2-byte channels each */ memset(prev_pixels, 0U, sizeof prev_pixels); for (x = 0U; x < width; x += max_pixels) { union { PNG_ROW_BUFFER_ALIGN_TYPE force_buffer_alignment; png_byte buffer[PNG_ROW_BUFFER_SIZE]; } pixel_buffer; if (max_pixels > width - x) max_pixels = (unsigned int)/*SAFE*/(width - x); debug((row_info_flags & png_row_end) == 0U); /* must be set here at end */ if (x + max_pixels >= width) row_info_flags |= png_row_end; /* Copy a block of input pixels into the buffer, effecting the interlace * on the way if required. The argument is the number of pixels in the * buffer, not the number handled from the input which will be larger in * the interlaced case. */ copy_fn(png_ptr, pixel_buffer.buffer, row, x, max_pixels, copy_parameter); /* Now pixel_buffer[0..max_pixels-1] contains max_pixels pixels which may * need to be transformed (the interlace has already been handled). */ # ifdef PNG_WRITE_TRANSFORMS_SUPPORTED if (png_ptr->transform_list != NULL) { png_transform_control tc; /* The initial values are the memory format; this was worked out in * png_init_row_info below. */ memset(&tc, 0, sizeof tc); tc.png_ptr = png_ptr; tc.sp = tc.dp = pixel_buffer.buffer; tc.width = max_pixels; /* width of block that we have */ 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 */ debug(PNG_TC_PIXEL_DEPTH(tc) == png_ptr->row_input_pixel_depth); /* 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)); } # endif /* WRITE_TRANSFORMS */ /* Call png_write_png_data to write this block of data, the test on * maxpixels says if this is the final block in the row. */ png_write_png_data(png_ptr, prev_pixels, pixel_buffer.buffer, x, max_pixels, row_info_flags); } } #endif /* WRITE { INTERLACING || TRANSFORMS } */ #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED static void copy_row(png_const_structrp png_ptr, png_bytep row_buffer, png_const_bytep row, png_uint_32 x, unsigned int count, unsigned int pixel_depth) { /* Copy row[x..x+count] pixels to row_buffer. */ png_copy_row(png_ptr, row_buffer, row, x, count, pixel_depth, 1/*clear*/, 0/* x_in_dest; row[x]->row_buffer */); } #endif /* WRITE_TRANSFORMS */ #ifdef PNG_WRITE_INTERLACING_SUPPORTED static void interlace_row_lbd(png_const_structrp png_ptr, png_bytep dp, png_const_bytep sp, png_uint_32 x, unsigned int count, const unsigned int B) { /* Pick out the correct pixels for the interlace pass. The basic idea here * is to go through the row with a source pointer and a destination pointer * (sp and dp), and copy the correct pixels for the pass. As the row gets * compacted, sp will always be >= dp, so we should never overwrite anything. * See the default: case for the easiest code to understand. */ const unsigned int pass = png_ptr->pass; png_uint_32 i = PNG_COL_FROM_PASS_COL(x, pass); const unsigned int inc = PNG_PASS_COL_OFFSET(pass); /* For pixels less than one byte wide the correct pixels have to be * extracted from the input bytes. Because we are reading data in * the application memory format we cannot rely on the PNG big * endian order. Notice that this was apparently broken before * 1.7.0. * * In libpng 1.7.0 libpng uses a classic bit-pump to optimize the * extraction. In all passes before the last (6/7) no two pixels * are adjacent in the input, so we are always extracting 1 bit. * At present the code uses an 8-bit buffer to avoid coding for * different byte sexes, but this could easily be changed. * * 'i' is the bit-index of bit in the input (sp[]), so, * considering the 1-bit per pixel case, sp[i>>3] is the byte * and the bit is bit (i&7) (0 lowest) on swapped (little endian) * data or 7-(i&7) on PNG default (big-endian) data. * * Define these macros, where: * * B: the log2 bit depth (0, 1, 2 for 1bpp, 2bpp or 4bpp) of * the data; this should be a constant. * sp: the source pointer (sp) (a png_const_bytep) * i: the pixel index in the input (png_uint_32) * j: the bit index in the output (unsigned int) * * Unlike 'i', 'j' is interpreted directly; for LSB bytes it counts * up, for MSB it counts down. * * NOTE: this could all be expanded to eliminate the code below by * the time honoured copy'n'paste into three separate functions. This * might be worth doing in the future. */ # define PIXEL_MASK ((1U << (1<>(3-(B))]) /* byte to use */ # define SP_OFFSET_LSB ((BIT_MASK & i) << (B)) # define SP_OFFSET_MSB ((BIT_MASK & ~i) << (B)) # define SP_PIXEL(sex) ((SP_BYTE >> SP_OFFSET_ ## sex) & PIXEL_MASK) { unsigned int j; unsigned int d; /* The data is always in the PNG, big-endian, format: */ for (j = 8U, d = 0U; count > 0U; --count, i += inc) { /* big-endian */ j -= 1U<pass; const unsigned int inc = PNG_PASS_COL_OFFSET(pass); /* Loop through the input copying each pixel to the correct place * in the output. Note that the loop may be executed 0 times if * this is called on a narrow image that does not contain this * pass. */ for (sp += PNG_COL_FROM_PASS_COL(x, pass) * cbytes; count > 0; --count, sp += inc * cbytes, dp += cbytes) memcpy(dp, sp, cbytes); } #endif /* WRITE_INTERLACING */ #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED static void write_row_core(png_structrp png_ptr, png_const_bytep row, unsigned int row_info_flags) { # ifdef PNG_WRITE_TRANSFORMS_SUPPORTED if (png_ptr->transform_list != NULL) write_row_buffered(png_ptr, row, row_info_flags, copy_row, png_ptr->row_input_pixel_depth); else # endif /* WRITE_TRANSFORMS */ /* If control reaches this point the intermediate buffer is not required and * the input data can be used unmodified. */ png_write_png_rows(png_ptr, &row, 1U); PNG_UNUSED(row_info_flags) } /* Write a single non-interlaced row. */ static void write_row_non_interlaced(png_structrp png_ptr, png_const_bytep row) { const png_uint_32 row_number = png_ptr->row_number+1U; /* There is only one pass, so this is the last pass: */ const unsigned int row_info_flags = (row_number == 1U ? png_pass_first_row : 0) | (row_number >= png_ptr->height ? png_pass_last_row : 0) | png_pass_last; debug(png_ptr->interlaced == PNG_INTERLACE_NONE); write_row_core(png_ptr, row, row_info_flags); } /* Write a single interlaced row. */ static void write_row_interlaced(png_structrp png_ptr, png_const_bytep row) { const png_uint_32 row_number = png_ptr->row_number+1U; const png_uint_32 height = png_ptr->height; const unsigned int pass = png_ptr->pass; const unsigned int row_info_flags = (row_number == 1U ? png_pass_first_row : 0) | (row_number == PNG_PASS_ROWS(height, pass) ? png_pass_last_row : 0) | (pass == PNG_LAST_PASS(png_ptr->width, height) ? png_pass_last : 0); # ifdef PNG_WRITE_INTERLACING_SUPPORTED /* Check that libpng is not doing the interlace: */ debug(png_ptr->interlaced != PNG_INTERLACE_NONE && !png_ptr->do_interlace); # endif /* WRITE_INTERLACING */ write_row_core(png_ptr, row, row_info_flags); } #endif /* WRITE_TRANSFORMS */ #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* Interlace a row then write it out. */ static void interlace_row(png_structrp png_ptr, png_const_bytep row) { /* The row may not exist in the image (for this pass). */ const png_uint_32 row_number = png_ptr->row_number; /* in image */ const unsigned int pass = png_ptr->pass; if (png_ptr->width > PNG_PASS_START_COL(pass) && PNG_ROW_IN_INTERLACE_PASS(row_number, pass)) { const unsigned int row_info_flags = (row_number == PNG_PASS_START_ROW(pass) ? png_pass_first_row : 0) | (PNG_LAST_PASS_ROW(row_number, pass, png_ptr->height) ? png_pass_last_row : 0) | (pass == PNG_LAST_PASS(png_ptr->width, png_ptr->height) ? png_pass_last : 0); if (pass < 6) { /* Libpng is doing the interlacing and pixels need to be selected * from the input row for this pass. */ /* row interlacing uses either the log bit depth for low bit * depth input or the byte count for 8bpp or bigger pixels. */ const unsigned int input_depth = png_ptr->row_input_pixel_depth; unsigned int B = 0; /* log2(input_depth) */ switch (input_depth) { case 4U: /* B will be 2 */ ++B; /*FALL THROUGH*/ case 2U: /* B will be 1 */ ++B; /*FALL THROUGH*/ case 1U: /* B will be 0 */ write_row_buffered(png_ptr, row, row_info_flags, interlace_row_lbd, B); break; default: /* Parameter is the pixel size in bytes */ write_row_buffered(png_ptr, row, row_info_flags, interlace_row_byte, input_depth >> 3); break; } } /* pass < 6 */ else /* pass 6: no interlacing required */ write_row_core(png_ptr, row, row_info_flags); } else { /* This code must advance row_number/pass itself; the row has been * skipped. */ if (row_number+1U < png_ptr->height) png_ptr->row_number = row_number+1U; else { png_ptr->row_number = 0U; png_ptr->pass = 0x7U & (pass+1U); } } } #endif /* WRITE_INTERLACING */ /* Bottleneck API to actually write a number of rows, only exists because the * rows parameter to png_write_rows is wrong. */ static void png_write_rows_internal(png_structrp png_ptr, png_const_bytep *rows, png_uint_32 num_rows) { if (png_ptr != NULL && num_rows > 0U && rows != NULL) { /* Unlike the read code initialization happens automatically: */ if (png_ptr->row_number == 0U && png_ptr->pass == 0U) { png_init_row_info(png_ptr); # ifdef PNG_WRITE_TRANSFORMS_SUPPORTED /* 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. * * 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 */ /* Perform initialization required before IDATs are written. */ png_write_start_IDAT(png_ptr); } else if (png_ptr->pass >= 7U) /* too many calls; write already ended */ { debug(png_ptr->row_number == 0U); png_app_error(png_ptr, "Too many calls to png_write_row"); return; } /* The remainder of these tests detect internal errors in libpng */ else if (png_ptr->interlaced == PNG_INTERLACE_NONE) affirm(png_ptr->row_number < png_ptr->height && png_ptr->pass == 0U); # ifdef PNG_WRITE_INTERLACING_SUPPORTED else if (png_ptr->do_interlace) affirm(png_ptr->row_number < png_ptr->height); # endif /* WRITE_INTERLACING */ else /* app does interlace */ affirm( PNG_PASS_IN_IMAGE(png_ptr->width, png_ptr->height, png_ptr->pass) && png_ptr->row_number < PNG_PASS_ROWS(png_ptr->height, png_ptr->pass) ); /* First handle rows that require buffering because of the need to * interlace them or the need to perform write transforms. */ # ifdef PNG_WRITE_INTERLACING_SUPPORTED /* libpng is doing the interlacing, but this only makes a difference to * the first six passes (numbered, in libpng, 0..5); the seventh pass * (numbered 6 by libpng) consists of complete image rows. */ if (png_ptr->do_interlace) while (num_rows > 0U && png_ptr->pass < 6) interlace_row(png_ptr, *rows++), --num_rows; # endif /* WRITE_INTERLACING */ # ifdef PNG_WRITE_TRANSFORMS_SUPPORTED /* Transforms required however the row interlacing has already been * handled and we have a complete (PNG) row. */ if (png_ptr->transform_list != NULL) { if (png_ptr->interlaced == PNG_INTERLACE_NONE) while (num_rows > 0U) write_row_non_interlaced(png_ptr, *rows++), --num_rows; # ifdef PNG_WRITE_INTERLACING_SUPPORTED else if (png_ptr->do_interlace) while (num_rows > 0U) interlace_row(png_ptr, *rows++), --num_rows; # endif /* WRITE_INTERLACING */ else /* app does the interlacing */ while (num_rows > 0U) write_row_interlaced(png_ptr, *rows++), --num_rows; } # endif /* WRITE_TRANSFORMS */ /* Finally handle any remaining rows that require no (libpng) interlace * and no transforms. */ if (num_rows > 0U) png_write_png_rows(png_ptr, rows, num_rows); /* Repeat the checks above, but allow for end-of-image. */ if (png_ptr->pass < 7U) { if (png_ptr->interlaced == PNG_INTERLACE_NONE) affirm(png_ptr->row_number < png_ptr->height && png_ptr->pass == 0U); # ifdef PNG_WRITE_INTERLACING_SUPPORTED else if (png_ptr->do_interlace) affirm(png_ptr->row_number < png_ptr->height); # endif /* WRITE_INTERLACING */ else /* app does interlace */ affirm(PNG_PASS_IN_IMAGE(png_ptr->width, png_ptr->height, png_ptr->pass) && png_ptr->row_number < PNG_PASS_ROWS(png_ptr->height, png_ptr->pass)); } } /* png_ptr, rows, num_rows all valid */ else if (png_ptr != NULL) png_app_warning(png_ptr, "Missing rows to row write API"); } /* ROW WRITE APIs */ /* Called by user to write a single row of image data */ void PNGAPI png_write_row(png_structrp png_ptr, png_const_bytep row) { png_debug(1, "in png_write_row"); png_write_rows_internal(png_ptr, &row, 1U); } /* 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 rows, png_uint_32 num_rows) { png_debug(1, "in png_write_rows"); if (png_ptr != NULL) png_write_rows_internal(png_ptr, png_constcast(png_const_bytep*,rows), num_rows); } /* 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_debug(1, "in png_write_image"); if (png_ptr != NULL) { int num_pass = 1; /* The image is always an non-interlaced image. To write it as interlaced * interlace handling must be present: */ if (png_ptr->interlaced) { # ifdef PNG_WRITE_INTERLACING_SUPPORTED num_pass = png_set_interlace_handling(png_ptr); # else /* !WRITE_INTERLACING */ /* There is no recovery because the IHDR has already been written. */ png_error(png_ptr, "No interlace support"); # endif /* !WRITE_INTERLACING */ } /* And write the whole thing, 7 times if interlacing it: */ for (; num_pass > 0; --num_pass) png_write_rows(png_ptr, image, png_ptr->height); } } /* 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"); png_deflate_destroy(png_ptr); #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); } } } 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 /* 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; ptrdiff_t 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; 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, also check the row stride * and total image size to ensure that they are within the system limits. */ { const unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format); /* The test is slightly evil: it assumes that a signed pointer difference * (ptrdiff_t) can hold a maximum value of half, rounded down, of the * maximum of a (size_t). This is almost certain to be true. */ if (image->width <= (PNG_SIZE_MAX >> 1)/channels) /* no overflow */ { png_alloc_size_t check; const png_alloc_size_t png_row_stride = (png_alloc_size_t)/*SAFE*/image->width * channels; if (display->row_stride == 0) display->row_stride = (ptrdiff_t)png_row_stride; if (display->row_stride < 0) check = -display->row_stride; else check = display->row_stride; if (check >= png_row_stride) { /* Now check for overflow of the image buffer calculation; check for * (size_t) overflow here. This detects issues with the * PNG_IMAGE_BUFFER_SIZE macro. */ if (image->height > PNG_SIZE_MAX/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_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; } /* Select the right compression mode based on the presence or absence of the * 'fast' flag. This will use whatever options are available in the libpng * build. It is always supported. */ png_set_compression(png_ptr, (image->flags & PNG_IMAGE_FLAG_FAST) != 0 ? PNG_COMPRESSION_HIGH_SPEED : PNG_COMPRESSION_HIGH); /* 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; } static void (PNGCBAPI image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data, png_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)*/); const 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, ptrdiff_t 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, ptrdiff_t 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_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, ptrdiff_t 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 */