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- /*---------------------------------------------------------------------------
- rpng - simple PNG display program readppm.c
- ---------------------------------------------------------------------------
- This is a special-purpose replacement for readpng.c that allows binary
- PPM files to be used in place of PNG images.
- ---------------------------------------------------------------------------
- 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 <stdio.h>
- #include <stdlib.h>
- #include "readpng.h" /* typedefs, common macros, public prototypes */
- ulg width, height;
- int bit_depth, color_type, channels;
- uch *image_data = NULL;
- FILE *saved_infile;
- void readpng_version_info()
- {
- fprintf(stderr, " Compiled without libpng, zlib or PBMPLUS/NetPBM.\n");
- }
- /* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
- int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
- {
- static uch ppmline[256];
- int maxval;
- saved_infile = infile;
- fgets(ppmline, 256, infile);
- if (ppmline[0] != 'P' || ppmline[1] != '6') {
- fprintf(stderr, "ERROR: not a PPM file\n");
- return 1;
- }
- /* possible color types: P5 = grayscale (0), P6 = RGB (2), P8 = RGBA (6) */
- if (ppmline[1] == '6') {
- color_type = 2;
- channels = 3;
- } else if (ppmline[1] == '8') {
- color_type = 6;
- channels = 4;
- } else /* if (ppmline[1] == '5') */ {
- color_type = 0;
- channels = 1;
- }
- do {
- fgets(ppmline, 256, infile);
- } while (ppmline[0] == '#');
- sscanf(ppmline, "%lu %lu", &width, &height);
- do {
- fgets(ppmline, 256, infile);
- } while (ppmline[0] == '#');
- sscanf(ppmline, "%d", &maxval);
- if (maxval != 255) {
- fprintf(stderr, "ERROR: maxval = %d\n", maxval);
- return 2;
- }
- bit_depth = 8;
- *pWidth = width;
- *pHeight = height;
- return 0;
- }
- /* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
- * scales values to 8-bit if necessary */
- int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
- {
- return 1;
- }
- /* display_exponent == LUT_exponent * CRT_exponent */
- uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
- {
- ulg rowbytes;
- /* 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] */
- /* GRR WARNING: grayscale needs to be expanded and channels reset! */
- *pRowbytes = rowbytes = channels*width;
- *pChannels = channels;
- if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
- return NULL;
- }
- Trace((stderr, "readpng_get_image: rowbytes = %ld, height = %ld\n", rowbytes, height));
- /* now we can go ahead and just read the whole image */
- if (fread(image_data, 1L, rowbytes*height, saved_infile) <
- rowbytes*height) {
- free (image_data);
- image_data = NULL;
- return NULL;
- }
- return image_data;
- }
- void readpng_cleanup(int free_image_data)
- {
- if (free_image_data && image_data) {
- free(image_data);
- image_data = NULL;
- }
- }
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