| /*--------------------------------------------------------------------------- |
| |
| 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; |
| } |
| } |