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Diffstat (limited to 'contrib/libpng/contrib/gregbook/readpng2.c')
| -rw-r--r-- | contrib/libpng/contrib/gregbook/readpng2.c | 505 |
1 files changed, 0 insertions, 505 deletions
diff --git a/contrib/libpng/contrib/gregbook/readpng2.c b/contrib/libpng/contrib/gregbook/readpng2.c deleted file mode 100644 index 1772a90..0000000 --- a/contrib/libpng/contrib/gregbook/readpng2.c +++ /dev/null @@ -1,505 +0,0 @@ -/*--------------------------------------------------------------------------- - - rpng2 - progressive-model PNG display program readpng2.c - - --------------------------------------------------------------------------- - - Copyright (c) 1998-2007 Greg Roelofs. All rights reserved. - - This software is provided "as is," without warranty of any kind, - express or implied. In no event shall the author or contributors - be held liable for any damages arising in any way from the use of - this software. - - The contents of this file are DUAL-LICENSED. You may modify and/or - redistribute this software according to the terms of one of the - following two licenses (at your option): - - - LICENSE 1 ("BSD-like with advertising clause"): - - Permission is granted to anyone to use this software for any purpose, - including commercial applications, and to alter it and redistribute - it freely, subject to the following restrictions: - - 1. Redistributions of source code must retain the above copyright - notice, disclaimer, and this list of conditions. - 2. Redistributions in binary form must reproduce the above copyright - notice, disclaimer, and this list of conditions in the documenta- - tion and/or other materials provided with the distribution. - 3. All advertising materials mentioning features or use of this - software must display the following acknowledgment: - - This product includes software developed by Greg Roelofs - and contributors for the book, "PNG: The Definitive Guide," - published by O'Reilly and Associates. - - - LICENSE 2 (GNU GPL v2 or later): - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 2 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software Foundation, - Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - - ---------------------------------------------------------------------------*/ - - -#include <stdlib.h> /* for exit() prototype */ -#include <setjmp.h> - -#include <zlib.h> -#include "png.h" /* libpng header from the local directory */ -#include "readpng2.h" /* typedefs, common macros, public prototypes */ - - -/* local prototypes */ - -static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr); -static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row, - png_uint_32 row_num, int pass); -static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr); -static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg); - - - - -void readpng2_version_info(void) -{ - fprintf(stderr, " Compiled with libpng %s; using libpng %s\n", - PNG_LIBPNG_VER_STRING, png_libpng_ver); - - fprintf(stderr, " and with zlib %s; using zlib %s.\n", - ZLIB_VERSION, zlib_version); -} - - - - -int readpng2_check_sig(uch *sig, int num) -{ - return !png_sig_cmp(sig, 0, num); -} - - - - -/* returns 0 for success, 2 for libpng problem, 4 for out of memory */ - -int readpng2_init(mainprog_info *mainprog_ptr) -{ - png_structp png_ptr; /* note: temporary variables! */ - png_infop info_ptr; - - - /* could also replace libpng warning-handler (final NULL), but no need: */ - - png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr, - readpng2_error_handler, NULL); - if (!png_ptr) - return 4; /* out of memory */ - - info_ptr = png_create_info_struct(png_ptr); - if (!info_ptr) { - png_destroy_read_struct(&png_ptr, NULL, NULL); - return 4; /* out of memory */ - } - - - /* we could create a second info struct here (end_info), but it's only - * useful if we want to keep pre- and post-IDAT chunk info separated - * (mainly for PNG-aware image editors and converters) */ - - - /* setjmp() must be called in every function that calls a PNG-reading - * libpng function, unless an alternate error handler was installed-- - * but compatible error handlers must either use longjmp() themselves - * (as in this program) or exit immediately, so here we are: */ - - if (setjmp(mainprog_ptr->jmpbuf)) { - png_destroy_read_struct(&png_ptr, &info_ptr, NULL); - return 2; - } - - -#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED - /* prepare the reader to ignore all recognized chunks whose data won't be - * used, i.e., all chunks recognized by libpng except for IHDR, PLTE, IDAT, - * IEND, tRNS, bKGD, gAMA, and sRGB (small performance improvement) */ - { - /* These byte strings were copied from png.h. If a future libpng - * version recognizes more chunks, add them to this list. If a - * future version of readpng2.c recognizes more chunks, delete them - * from this list. */ - static /* const */ png_byte chunks_to_ignore[] = { - 99, 72, 82, 77, '\0', /* cHRM */ - 104, 73, 83, 84, '\0', /* hIST */ - 105, 67, 67, 80, '\0', /* iCCP */ - 105, 84, 88, 116, '\0', /* iTXt */ - 111, 70, 70, 115, '\0', /* oFFs */ - 112, 67, 65, 76, '\0', /* pCAL */ - 112, 72, 89, 115, '\0', /* pHYs */ - 115, 66, 73, 84, '\0', /* sBIT */ - 115, 67, 65, 76, '\0', /* sCAL */ - 115, 80, 76, 84, '\0', /* sPLT */ - 115, 84, 69, 82, '\0', /* sTER */ - 116, 69, 88, 116, '\0', /* tEXt */ - 116, 73, 77, 69, '\0', /* tIME */ - 122, 84, 88, 116, '\0' /* zTXt */ - }; - - png_set_keep_unknown_chunks(png_ptr, 1 /* PNG_HANDLE_CHUNK_NEVER */, - chunks_to_ignore, sizeof(chunks_to_ignore)/5); - } -#endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */ - - - /* instead of doing png_init_io() here, now we set up our callback - * functions for progressive decoding */ - - png_set_progressive_read_fn(png_ptr, mainprog_ptr, - readpng2_info_callback, readpng2_row_callback, readpng2_end_callback); - - - /* make sure we save our pointers for use in readpng2_decode_data() */ - - mainprog_ptr->png_ptr = png_ptr; - mainprog_ptr->info_ptr = info_ptr; - - - /* and that's all there is to initialization */ - - return 0; -} - - - - -/* returns 0 for success, 2 for libpng (longjmp) problem */ - -int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length) -{ - png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr; - png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr; - - - /* setjmp() must be called in every function that calls a PNG-reading - * libpng function */ - - if (setjmp(mainprog_ptr->jmpbuf)) { - png_destroy_read_struct(&png_ptr, &info_ptr, NULL); - mainprog_ptr->png_ptr = NULL; - mainprog_ptr->info_ptr = NULL; - return 2; - } - - - /* hand off the next chunk of input data to libpng for decoding */ - - png_process_data(png_ptr, info_ptr, rawbuf, length); - - return 0; -} - - - - -static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr) -{ - mainprog_info *mainprog_ptr; - int color_type, bit_depth; - png_uint_32 width, height; -#ifdef PNG_FLOATING_POINT_SUPPORTED - double gamma; -#else - png_fixed_point gamma; -#endif - - - /* setjmp() doesn't make sense here, because we'd either have to exit(), - * longjmp() ourselves, or return control to libpng, which doesn't want - * to see us again. By not doing anything here, libpng will instead jump - * to readpng2_decode_data(), which can return an error value to the main - * program. */ - - - /* retrieve the pointer to our special-purpose struct, using the png_ptr - * that libpng passed back to us (i.e., not a global this time--there's - * no real difference for a single image, but for a multithreaded browser - * decoding several PNG images at the same time, one needs to avoid mixing - * up different images' structs) */ - - mainprog_ptr = png_get_progressive_ptr(png_ptr); - - if (mainprog_ptr == NULL) { /* we be hosed */ - fprintf(stderr, - "readpng2 error: main struct not recoverable in info_callback.\n"); - fflush(stderr); - return; - /* - * Alternatively, we could call our error-handler just like libpng - * does, which would effectively terminate the program. Since this - * can only happen if png_ptr gets redirected somewhere odd or the - * main PNG struct gets wiped, we're probably toast anyway. (If - * png_ptr itself is NULL, we would not have been called.) - */ - } - - - /* this is just like in the non-progressive case */ - - png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, - NULL, NULL, NULL); - mainprog_ptr->width = (ulg)width; - mainprog_ptr->height = (ulg)height; - - - /* since we know we've read all of the PNG file's "header" (i.e., up - * to IDAT), we can check for a background color here */ - - if (mainprog_ptr->need_bgcolor && - png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD)) - { - png_color_16p pBackground; - - /* it is not obvious from the libpng documentation, but this function - * takes a pointer to a pointer, and it always returns valid red, - * green and blue values, regardless of color_type: */ - png_get_bKGD(png_ptr, info_ptr, &pBackground); - - /* however, it always returns the raw bKGD data, regardless of any - * bit-depth transformations, so check depth and adjust if necessary */ - if (bit_depth == 16) { - mainprog_ptr->bg_red = pBackground->red >> 8; - mainprog_ptr->bg_green = pBackground->green >> 8; - mainprog_ptr->bg_blue = pBackground->blue >> 8; - } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) { - if (bit_depth == 1) - mainprog_ptr->bg_red = mainprog_ptr->bg_green = - mainprog_ptr->bg_blue = pBackground->gray? 255 : 0; - else if (bit_depth == 2) - mainprog_ptr->bg_red = mainprog_ptr->bg_green = - mainprog_ptr->bg_blue = (255/3) * pBackground->gray; - else /* bit_depth == 4 */ - mainprog_ptr->bg_red = mainprog_ptr->bg_green = - mainprog_ptr->bg_blue = (255/15) * pBackground->gray; - } else { - mainprog_ptr->bg_red = (uch)pBackground->red; - mainprog_ptr->bg_green = (uch)pBackground->green; - mainprog_ptr->bg_blue = (uch)pBackground->blue; - } - } - - - /* as before, let libpng expand palette images to RGB, low-bit-depth - * grayscale images to 8 bits, transparency chunks to full alpha channel; - * strip 16-bit-per-sample images to 8 bits per sample; and convert - * grayscale to RGB[A] */ - - if (color_type == PNG_COLOR_TYPE_PALETTE) - png_set_expand(png_ptr); - if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) - png_set_expand(png_ptr); - if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) - png_set_expand(png_ptr); - if (bit_depth == 16) - png_set_strip_16(png_ptr); - if (color_type == PNG_COLOR_TYPE_GRAY || - color_type == PNG_COLOR_TYPE_GRAY_ALPHA) - png_set_gray_to_rgb(png_ptr); - - - /* Unlike the basic viewer, which was designed to operate on local files, - * this program is intended to simulate a web browser--even though we - * actually read from a local file, too. But because we are pretending - * that most of the images originate on the Internet, we follow the recom- - * mendation of the sRGB proposal and treat unlabelled images (no gAMA - * chunk) as existing in the sRGB color space. That is, we assume that - * such images have a file gamma of 0.45455, which corresponds to a PC-like - * display system. This change in assumptions will have no effect on a - * PC-like system, but on a Mac, SGI, NeXT or other system with a non- - * identity lookup table, it will darken unlabelled images, which effec- - * tively favors images from PC-like systems over those originating on - * the local platform. Note that mainprog_ptr->display_exponent is the - * "gamma" value for the entire display system, i.e., the product of - * LUT_exponent and CRT_exponent. */ - -#ifdef PNG_FLOATING_POINT_SUPPORTED - if (png_get_gAMA(png_ptr, info_ptr, &gamma)) - png_set_gamma(png_ptr, mainprog_ptr->display_exponent, gamma); - else - png_set_gamma(png_ptr, mainprog_ptr->display_exponent, 0.45455); -#else - if (png_get_gAMA_fixed(png_ptr, info_ptr, &gamma)) - png_set_gamma_fixed(png_ptr, - (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), gamma); - else - png_set_gamma_fixed(png_ptr, - (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), 45455); -#endif - - /* we'll let libpng expand interlaced images, too */ - - mainprog_ptr->passes = png_set_interlace_handling(png_ptr); - - - /* all transformations have been registered; now update info_ptr data and - * then get rowbytes and channels */ - - png_read_update_info(png_ptr, info_ptr); - - mainprog_ptr->rowbytes = (int)png_get_rowbytes(png_ptr, info_ptr); - mainprog_ptr->channels = png_get_channels(png_ptr, info_ptr); - - - /* Call the main program to allocate memory for the image buffer and - * initialize windows and whatnot. (The old-style function-pointer - * invocation is used for compatibility with a few supposedly ANSI - * compilers that nevertheless barf on "fn_ptr()"-style syntax.) */ - - (*mainprog_ptr->mainprog_init)(); - - - /* and that takes care of initialization */ - - return; -} - - - - - -static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row, - png_uint_32 row_num, int pass) -{ - mainprog_info *mainprog_ptr; - - - /* first check whether the row differs from the previous pass; if not, - * nothing to combine or display */ - - if (!new_row) - return; - - - /* retrieve the pointer to our special-purpose struct so we can access - * the old rows and image-display callback function */ - - mainprog_ptr = png_get_progressive_ptr(png_ptr); - - - /* save the pass number for optional use by the front end */ - - mainprog_ptr->pass = pass; - - - /* have libpng either combine the new row data with the existing row data - * from previous passes (if interlaced) or else just copy the new row - * into the main program's image buffer */ - - png_progressive_combine_row(png_ptr, mainprog_ptr->row_pointers[row_num], - new_row); - - - /* finally, call the display routine in the main program with the number - * of the row we just updated */ - - (*mainprog_ptr->mainprog_display_row)(row_num); - - - /* and we're ready for more */ - - return; -} - - - - - -static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr) -{ - mainprog_info *mainprog_ptr; - - - /* retrieve the pointer to our special-purpose struct */ - - mainprog_ptr = png_get_progressive_ptr(png_ptr); - - - /* let the main program know that it should flush any buffered image - * data to the display now and set a "done" flag or whatever, but note - * that it SHOULD NOT DESTROY THE PNG STRUCTS YET--in other words, do - * NOT call readpng2_cleanup() either here or in the finish_display() - * routine; wait until control returns to the main program via - * readpng2_decode_data() */ - - (*mainprog_ptr->mainprog_finish_display)(); - - - /* all done */ - - return; -} - - - - - -void readpng2_cleanup(mainprog_info *mainprog_ptr) -{ - png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr; - png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr; - - if (png_ptr && info_ptr) - png_destroy_read_struct(&png_ptr, &info_ptr, NULL); - - mainprog_ptr->png_ptr = NULL; - mainprog_ptr->info_ptr = NULL; -} - - - - - -static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg) -{ - mainprog_info *mainprog_ptr; - - /* This function, aside from the extra step of retrieving the "error - * pointer" (below) and the fact that it exists within the application - * rather than within libpng, is essentially identical to libpng's - * default error handler. The second point is critical: since both - * setjmp() and longjmp() are called from the same code, they are - * guaranteed to have compatible notions of how big a jmp_buf is, - * regardless of whether _BSD_SOURCE or anything else has (or has not) - * been defined. */ - - fprintf(stderr, "readpng2 libpng error: %s\n", msg); - fflush(stderr); - - mainprog_ptr = png_get_error_ptr(png_ptr); - if (mainprog_ptr == NULL) { /* we are completely hosed now */ - fprintf(stderr, - "readpng2 severe error: jmpbuf not recoverable; terminating.\n"); - fflush(stderr); - exit(99); - } - - /* Now we have our data structure we can use the information in it - * to return control to our own higher level code (all the points - * where 'setjmp' is called in this file.) This will work with other - * error handling mechanisms as well - libpng always calls png_error - * when it can proceed no further, thus, so long as the error handler - * is intercepted, application code can do its own error recovery. - */ - longjmp(mainprog_ptr->jmpbuf, 1); -} |