wrlib/ppm.c

   1 /* ppm.c - load PPM image from file
   2  *
   3  *  Raster graphics library
   4  *
   5  *  Copyright (c) 1997 Alfredo K. Kojima
   6  *
   7  *  This library is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU Library General Public
   9  *  License as published by the Free Software Foundation; either
  10  *  version 2 of the License, or (at your option) any later version.
  11  *
  12  *  This library is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *  Library General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU Library General Public
  18  *  License along with this library; if not, write to the Free
  19  *  Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include <config.h>
  23
  24
  25 #include <X11/Xlib.h>
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29
  30 #include "wraster.h"
  31
  32
  33 static RImage*
  34 load_graymap(char *file_name, FILE *file, int w, int h, int max, int raw)
  35 {
  36     RImage *image;
  37
  38     image = RCreateImage(w, h, 0);
  39     if (!image) {
  40         sprintf(RErrorString, "out of memory");
  41         return NULL;
  42     }
  43     if (!raw) {
  44
  45     } else {
  46         if (max<256) {
  47             if (!fgets(image->data[0], w*h, file))
  48                 goto short_file;
  49             memcpy(image->data[0], image->data[1], w*h);
  50             memcpy(image->data[0], image->data[2], w*h);
  51         } else {
  52
  53         }
  54     }
  55
  56     return image;
  57
  58   short_file:
  59     sprintf(RErrorString, "PPM file \"%s\" seems to be truncated", file_name);
  60     return NULL;
  61 }
  62
  63
  64 static RImage*
  65 load_pixmap(char *file_name, FILE *file, int w, int h, int max, int raw)
  66 {
  67     RImage *image;
  68     int i;
  69     char buf[3];
  70     char *r, *g, *b;
  71
  72     image = RCreateImage(w, h, 0);
  73     if (!image) {
  74         sprintf(RErrorString, "out of memory");
  75         return NULL;
  76     }
  77     r = image->data[0];
  78     g = image->data[1];
  79     b = image->data[2];
  80     if (!raw) {
  81
  82     } else {
  83         if (max<256) {
  84             i = 0;
  85             while (i < w*h) {
  86                 if (fread(buf, 1, 3, file)!=3)
  87                     goto short_file;
  88                 *(r++) = buf[0];
  89                 *(g++) = buf[1];
  90                 *(b++) = buf[2];
  91                 i++;
  92             }
  93         } else {
  94
  95         }
  96     }
  97
  98     return image;
  99
 100   short_file:
 101     sprintf(RErrorString, "PPM file \"%s\" seems to be truncated", file_name);
 102     return NULL;
 103 }
 104
 105
 106 RImage*
 107 RLoadPPM(RContext *context, char *file_name, int index)
 108 {
 109     FILE *file;
 110     RImage *image = NULL;
 111     char buffer[256];
 112     int w, h, m;
 113     int type;
 114
 115 #define GETL() if (!fgets(buffer, 255, file)) goto short_file
 116
 117     RErrorString[0] = 0;
 118
 119     file = fopen(file_name, "r");
 120     if (!file) {
 121         sprintf(RErrorString, "could not open PPM file \"%s\"", file_name);
 122         return NULL;
 123     }
 124
 125     /* get signature */
 126     GETL();
 127
 128     /* only accept raw pixmaps or graymaps */
 129     if (buffer[0] != 'P' || (buffer[1] != '5' && buffer[1] != '6')) {
 130         sprintf(RErrorString, "unknown PPM format in \"%s\"", file_name);
 131         fclose(file);
 132         return NULL;
 133     }
 134
 135     type = buffer[1];
 136
 137     /* skip comments */
 138     while (1) {
 139         GETL();
 140
 141         if (buffer[0]!='#')
 142             break;
 143     }
 144
 145     /* get size */
 146     if (sscanf(buffer, "%i %i", &w, &h)!=2)
 147         goto bad_file;
 148
 149
 150     GETL();
 151     if (sscanf(buffer, "%i", &m)!=1 || m < 1)
 152         goto bad_file;
 153
 154     if (type=='5')
 155         image = load_graymap(file_name, file, w, h, m, type=='5');
 156     else if (type=='6')
 157         image = load_pixmap(file_name, file, w, h, m, type=='6');
 158
 159     fclose(file);
 160     return image;
 161
 162   bad_file:
 163     sprintf(RErrorString, "PPM file \"%s\" seems to be corrupted", file_name);
 164     fclose(file);
 165     return NULL;
 166
 167   short_file:
 168     sprintf(RErrorString, "PPM file \"%s\" seems to be truncated", file_name);
 169     fclose(file);
 170     return NULL;
 171 }
 172