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         return NULL;
  41     }
  42     if (!raw) {
  43
  44     } else {
  45         if (max<256) {
  46             int x, y;
  47             char *buf, *ptr;
  48
  49             buf = malloc(w+1);
  50             if (!buf) {
  51                 return NULL;
  52             }
  53
  54             ptr = image->data;
  55             for (y = 0; y < h; y++) {
  56                 if (!fread(buf, w, 1, file)) {
  57                     free(buf);
  58                     goto short_file;
  59                 }
  60                 for (x = 0; x < w; x++) {
  61                     *(ptr++) = buf[x];
  62                     *(ptr++) = buf[x];
  63                     *(ptr++) = buf[x];
  64                 }
  65             }
  66             free(buf);
  67         } else {
  68
  69         }
  70     }
  71
  72     return image;
  73
  74   short_file:
  75     RErrorCode = RERR_BADIMAGEFILE;
  76     return NULL;
  77 }
  78
  79
  80 static RImage*
  81 load_pixmap(char *file_name, FILE *file, int w, int h, int max, int raw)
  82 {
  83     RImage *image;
  84     int i;
  85     char buf[3];
  86     char *ptr;
  87
  88     image = RCreateImage(w, h, 0);
  89     if (!image) {
  90         return NULL;
  91     }
  92     ptr = image->data;
  93     if (!raw) {
  94
  95     } else {
  96         if (max<256) {
  97             i = 0;
  98             while (i < w*h) {
  99                 if (fread(buf, 1, 3, file)!=3)
 100                     goto short_file;
 101                 *(ptr++) = buf[0];
 102                 *(ptr++) = buf[1];
 103                 *(ptr++) = buf[2];
 104                 i++;
 105             }
 106         } else {
 107
 108         }
 109     }
 110
 111     return image;
 112
 113   short_file:
 114     RErrorCode = RERR_BADIMAGEFILE;
 115     return NULL;
 116 }
 117
 118
 119 RImage*
 120 RLoadPPM(RContext *context, char *file_name, int index)
 121 {
 122     FILE *file;
 123     RImage *image = NULL;
 124     char buffer[256];
 125     int w, h, m;
 126     int type;
 127
 128 #define GETL() if (!fgets(buffer, 255, file)) goto short_file
 129
 130     file = fopen(file_name, "r");
 131     if (!file) {
 132         RErrorCode = RERR_OPEN;
 133         return NULL;
 134     }
 135
 136     /* get signature */
 137     GETL();
 138
 139     /* only accept raw pixmaps or graymaps */
 140     if (buffer[0] != 'P' || (buffer[1] != '5' && buffer[1] != '6')) {
 141         RErrorCode = RERR_BADFORMAT;
 142         fclose(file);
 143         return NULL;
 144     }
 145
 146     type = buffer[1];
 147
 148     /* skip comments */
 149     while (1) {
 150         GETL();
 151
 152         if (buffer[0]!='#')
 153             break;
 154     }
 155
 156     /* get size */
 157     if (sscanf(buffer, "%i %i", &w, &h)!=2)
 158         goto bad_file;
 159
 160
 161     GETL();
 162     if (sscanf(buffer, "%i", &m)!=1 || m < 1)
 163         goto bad_file;
 164
 165     if (type=='5')
 166         image = load_graymap(file_name, file, w, h, m, type=='5');
 167     else if (type=='6')
 168         image = load_pixmap(file_name, file, w, h, m, type=='6');
 169
 170     fclose(file);
 171     return image;
 172
 173   bad_file:
 174   short_file:
 175     RErrorCode = RERR_BADIMAGEFILE;
 176     fclose(file);
 177     return NULL;
 178 }
 179