fukasawa e60969
/*---------------------------------------------------------------------------
fukasawa e60969
fukasawa e60969
   rpng - simple PNG display program                              readppm.c
fukasawa e60969
fukasawa e60969
  ---------------------------------------------------------------------------
fukasawa e60969
fukasawa e60969
   This is a special-purpose replacement for readpng.c that allows binary
fukasawa e60969
   PPM files to be used in place of PNG images.
fukasawa e60969
fukasawa e60969
  ---------------------------------------------------------------------------
fukasawa e60969
fukasawa e60969
      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
fukasawa e60969
fukasawa e60969
      This software is provided "as is," without warranty of any kind,
fukasawa e60969
      express or implied.  In no event shall the author or contributors
fukasawa e60969
      be held liable for any damages arising in any way from the use of
fukasawa e60969
      this software.
fukasawa e60969
fukasawa e60969
      The contents of this file are DUAL-LICENSED.  You may modify and/or
fukasawa e60969
      redistribute this software according to the terms of one of the
fukasawa e60969
      following two licenses (at your option):
fukasawa e60969
fukasawa e60969
fukasawa e60969
      LICENSE 1 ("BSD-like with advertising clause"):
fukasawa e60969
fukasawa e60969
      Permission is granted to anyone to use this software for any purpose,
fukasawa e60969
      including commercial applications, and to alter it and redistribute
fukasawa e60969
      it freely, subject to the following restrictions:
fukasawa e60969
fukasawa e60969
      1. Redistributions of source code must retain the above copyright
fukasawa e60969
         notice, disclaimer, and this list of conditions.
fukasawa e60969
      2. Redistributions in binary form must reproduce the above copyright
fukasawa e60969
         notice, disclaimer, and this list of conditions in the documenta-
fukasawa e60969
         tion and/or other materials provided with the distribution.
fukasawa e60969
      3. All advertising materials mentioning features or use of this
fukasawa e60969
         software must display the following acknowledgment:
fukasawa e60969
fukasawa e60969
            This product includes software developed by Greg Roelofs
fukasawa e60969
            and contributors for the book, "PNG: The Definitive Guide,"
fukasawa e60969
            published by O'Reilly and Associates.
fukasawa e60969
fukasawa e60969
fukasawa e60969
      LICENSE 2 (GNU GPL v2 or later):
fukasawa e60969
fukasawa e60969
      This program is free software; you can redistribute it and/or modify
fukasawa e60969
      it under the terms of the GNU General Public License as published by
fukasawa e60969
      the Free Software Foundation; either version 2 of the License, or
fukasawa e60969
      (at your option) any later version.
fukasawa e60969
fukasawa e60969
      This program is distributed in the hope that it will be useful,
fukasawa e60969
      but WITHOUT ANY WARRANTY; without even the implied warranty of
fukasawa e60969
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
fukasawa e60969
      GNU General Public License for more details.
fukasawa e60969
fukasawa e60969
      You should have received a copy of the GNU General Public License
fukasawa e60969
      along with this program; if not, write to the Free Software Foundation,
fukasawa e60969
      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
fukasawa e60969
fukasawa e60969
  ---------------------------------------------------------------------------*/
fukasawa e60969
fukasawa e60969
#include <stdio.h></stdio.h>
fukasawa e60969
#include <stdlib.h></stdlib.h>
fukasawa e60969
fukasawa e60969
#include "readpng.h"    /* typedefs, common macros, public prototypes */
fukasawa e60969
fukasawa e60969
fukasawa e60969
ulg  width, height;
fukasawa e60969
int  bit_depth, color_type, channels;
fukasawa e60969
uch  *image_data = NULL;
fukasawa e60969
FILE *saved_infile;
fukasawa e60969
fukasawa e60969
fukasawa e60969
void readpng_version_info()
fukasawa e60969
{
fukasawa e60969
    fprintf(stderr, "   Compiled without libpng, zlib or PBMPLUS/NetPBM.\n");
fukasawa e60969
}
fukasawa e60969
fukasawa e60969
fukasawa e60969
/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
fukasawa e60969
fukasawa e60969
int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
fukasawa e60969
{
fukasawa e60969
    static uch ppmline[256];
fukasawa e60969
    int maxval;
fukasawa e60969
fukasawa e60969
fukasawa e60969
    saved_infile = infile;
fukasawa e60969
fukasawa e60969
    fgets(ppmline, 256, infile);
fukasawa e60969
    if (ppmline[0] != 'P' || ppmline[1] != '6') {
fukasawa e60969
        fprintf(stderr, "ERROR:  not a PPM file\n");
fukasawa e60969
        return 1;
fukasawa e60969
    }
fukasawa e60969
    /* possible color types:  P5 = grayscale (0), P6 = RGB (2), P8 = RGBA (6) */
fukasawa e60969
    if (ppmline[1] == '6') {
fukasawa e60969
        color_type = 2;
fukasawa e60969
        channels = 3;
fukasawa e60969
    } else if (ppmline[1] == '8') {
fukasawa e60969
        color_type = 6;
fukasawa e60969
        channels = 4;
fukasawa e60969
    } else /* if (ppmline[1] == '5') */ {
fukasawa e60969
        color_type = 0;
fukasawa e60969
        channels = 1;
fukasawa e60969
    }
fukasawa e60969
fukasawa e60969
    do {
fukasawa e60969
        fgets(ppmline, 256, infile);
fukasawa e60969
    } while (ppmline[0] == '#');
fukasawa e60969
    sscanf(ppmline, "%lu %lu", &width, &height);
fukasawa e60969
fukasawa e60969
    do {
fukasawa e60969
        fgets(ppmline, 256, infile);
fukasawa e60969
    } while (ppmline[0] == '#');
fukasawa e60969
    sscanf(ppmline, "%d", &maxval);
fukasawa e60969
    if (maxval != 255) {
fukasawa e60969
        fprintf(stderr, "ERROR:  maxval = %d\n", maxval);
fukasawa e60969
        return 2;
fukasawa e60969
    }
fukasawa e60969
    bit_depth = 8;
fukasawa e60969
fukasawa e60969
    *pWidth = width;
fukasawa e60969
    *pHeight = height;
fukasawa e60969
fukasawa e60969
    return 0;
fukasawa e60969
}
fukasawa e60969
fukasawa e60969
fukasawa e60969
fukasawa e60969
fukasawa e60969
/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
fukasawa e60969
 * scales values to 8-bit if necessary */
fukasawa e60969
fukasawa e60969
int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
fukasawa e60969
{
fukasawa e60969
    return 1;
fukasawa e60969
}
fukasawa e60969
fukasawa e60969
fukasawa e60969
fukasawa e60969
fukasawa e60969
/* display_exponent == LUT_exponent * CRT_exponent */
fukasawa e60969
fukasawa e60969
uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
fukasawa e60969
{
fukasawa e60969
    ulg  rowbytes;
fukasawa e60969
fukasawa e60969
fukasawa e60969
    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
fukasawa e60969
     * transparency chunks to full alpha channel; strip 16-bit-per-sample
fukasawa e60969
     * images to 8 bits per sample; and convert grayscale to RGB[A] */
fukasawa e60969
fukasawa e60969
    /* GRR WARNING:  grayscale needs to be expanded and channels reset! */
fukasawa e60969
fukasawa e60969
    *pRowbytes = rowbytes = channels*width;
fukasawa e60969
    *pChannels = channels;
fukasawa e60969
fukasawa e60969
    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
fukasawa e60969
        return NULL;
fukasawa e60969
    }
fukasawa e60969
fukasawa e60969
    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
fukasawa e60969
fukasawa e60969
fukasawa e60969
    /* now we can go ahead and just read the whole image */
fukasawa e60969
fukasawa e60969
    if (fread(image_data, 1L, rowbytes*height, saved_infile) <
fukasawa e60969
       rowbytes*height) {
fukasawa e60969
        free (image_data);
fukasawa e60969
        image_data = NULL;
fukasawa e60969
        return NULL;
fukasawa e60969
    }
fukasawa e60969
fukasawa e60969
    return image_data;
fukasawa e60969
}
fukasawa e60969
fukasawa e60969
fukasawa e60969
void readpng_cleanup(int free_image_data)
fukasawa e60969
{
fukasawa e60969
    if (free_image_data && image_data) {
fukasawa e60969
        free(image_data);
fukasawa e60969
        image_data = NULL;
fukasawa e60969
    }
fukasawa e60969
}