wrlib/load_gif.c

   1 /* gif.c - load GIF image from file
   2  *
   3  * Raster graphics library
   4  *
   5  * Copyright (c) 1998-2003 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., 51 Franklin St, Fifth Floor, Boston,
  20  *  MA 02110-1301, USA.
  21  */
  22
  23 #include <config.h>
  24
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28
  29 #include <gif_lib.h>
  30
  31 #include "wraster.h"
  32 #include "imgformat.h"
  33
  34 static int InterlacedOffset[] = { 0, 4, 2, 1 };
  35 static int InterlacedJumps[] = { 8, 8, 4, 2 };
  36
  37 /*
  38  * Partially based on code in gif2rgb from giflib, by Gershon Elber.
  39  */
  40 RImage *RLoadGIF(const char *file, int index)
  41 {
  42         RImage *image = NULL;
  43         unsigned char *cptr;
  44         GifFileType *gif = NULL;
  45         GifPixelType *buffer = NULL;
  46         int i, j, k;
  47         int width, height;
  48         GifRecordType recType;
  49         ColorMapObject *colormap;
  50         unsigned char rmap[256], gmap[256], bmap[256];
  51         int gif_error;
  52
  53         if (index < 0)
  54                 index = 0;
  55
  56         /* default error message */
  57         RErrorCode = RERR_BADINDEX;
  58
  59 #if USE_GIF == 4
  60         gif = DGifOpenFileName(file);
  61 #else /* USE_GIF == 5 */
  62         gif = DGifOpenFileName(file, &gif_error);
  63 #endif
  64
  65         if (!gif) {
  66 #if USE_GIF == 4
  67                 gif_error = GifLastError();
  68 #endif
  69                 switch (gif_error) {
  70                 case D_GIF_ERR_OPEN_FAILED:
  71                         RErrorCode = RERR_OPEN;
  72                         break;
  73                 case D_GIF_ERR_READ_FAILED:
  74                         RErrorCode = RERR_READ;
  75                         break;
  76                 default:
  77                         RErrorCode = RERR_BADIMAGEFILE;
  78                         break;
  79                 }
  80                 return NULL;
  81         }
  82
  83         if (gif->SWidth < 1 || gif->SHeight < 1) {
  84                 DGifCloseFile(gif);
  85                 RErrorCode = RERR_BADIMAGEFILE;
  86                 return NULL;
  87         }
  88
  89         colormap = gif->SColorMap;
  90         i = 0;
  91
  92         do {
  93                 int extCode;
  94                 GifByteType *extension;
  95
  96                 if (DGifGetRecordType(gif, &recType) == GIF_ERROR)
  97                         goto giferr;
  98
  99                 switch (recType) {
 100                 case IMAGE_DESC_RECORD_TYPE:
 101                         if (i++ != index)
 102                                 break;
 103
 104                         if (DGifGetImageDesc(gif) == GIF_ERROR)
 105                                 goto giferr;
 106
 107                         width = gif->Image.Width;
 108                         height = gif->Image.Height;
 109
 110                         if (gif->Image.ColorMap)
 111                                 colormap = gif->Image.ColorMap;
 112
 113                         /* the gif specs talk about a default colormap, but it
 114                          * doesnt say what the heck is this default colormap
 115                          * Render anything */
 116                         if (colormap) {
 117                                 for (j = 0; j < colormap->ColorCount; j++) {
 118                                         rmap[j] = colormap->Colors[j].Red;
 119                                         gmap[j] = colormap->Colors[j].Green;
 120                                         bmap[j] = colormap->Colors[j].Blue;
 121                                 }
 122                         }
 123
 124                         buffer = malloc(width * sizeof(GifPixelType));
 125                         if (!buffer) {
 126                                 RErrorCode = RERR_NOMEMORY;
 127                                 goto bye;
 128                         }
 129
 130                         image = RCreateImage(width, height, False);
 131                         if (!image)
 132                                 goto bye;
 133
 134                         if (gif->Image.Interlace) {
 135                                 int l, pelsPerLine;
 136
 137                                 if (RRGBAFormat == image->format)
 138                                         pelsPerLine = width * 4;
 139                                 else
 140                                         pelsPerLine = width * 3;
 141
 142                                 for (j = 0; j < 4; j++) {
 143                                         for (k = InterlacedOffset[j]; k < height; k += InterlacedJumps[j]) {
 144                                                 if (DGifGetLine(gif, buffer, width) == GIF_ERROR)
 145                                                         goto giferr;
 146
 147                                                 cptr = image->data + (k * pelsPerLine);
 148                                                 for (l = 0; l < width; l++) {
 149                                                         int pixel = buffer[l];
 150                                                         *cptr++ = rmap[pixel];
 151                                                         *cptr++ = gmap[pixel];
 152                                                         *cptr++ = bmap[pixel];
 153                                                 }
 154                                         }
 155                                 }
 156                         } else {
 157                                 cptr = image->data;
 158                                 for (j = 0; j < height; j++) {
 159                                         if (DGifGetLine(gif, buffer, width) == GIF_ERROR)
 160                                                 goto giferr;
 161
 162                                         for (k = 0; k < width; k++) {
 163                                                 int pixel = buffer[k];
 164                                                 *cptr++ = rmap[pixel];
 165                                                 *cptr++ = gmap[pixel];
 166                                                 *cptr++ = bmap[pixel];
 167                                                 if (RRGBAFormat == image->format)
 168                                                         cptr++;
 169                                         }
 170                                 }
 171                         }
 172                         break;
 173
 174                 case EXTENSION_RECORD_TYPE:
 175                         /* skip all extension blocks */
 176                         if (DGifGetExtension(gif, &extCode, &extension) == GIF_ERROR)
 177                                 goto giferr;
 178
 179                         while (extension)
 180                                 if (DGifGetExtensionNext(gif, &extension) == GIF_ERROR)
 181                                         goto giferr;
 182
 183                         break;
 184
 185                 default:
 186                         break;
 187                 }
 188         } while (recType != TERMINATE_RECORD_TYPE && i <= index);
 189
 190         /* yuck! */
 191         goto did_not_get_any_errors;
 192  giferr:
 193 #if USE_GIF == 4
 194         switch (GifLastError()) {
 195         case D_GIF_ERR_OPEN_FAILED:
 196                 RErrorCode = RERR_OPEN;
 197                 break;
 198         case D_GIF_ERR_READ_FAILED:
 199                 RErrorCode = RERR_READ;
 200                 break;
 201         default:
 202                 RErrorCode = RERR_BADIMAGEFILE;
 203                 break;
 204         }
 205 #else
 206         /* With gif_lib v5 there's no way to know what went wrong */
 207         RErrorCode = RERR_BADIMAGEFILE;
 208 #endif
 209  bye:
 210         if (image)
 211                 RReleaseImage(image);
 212         image = NULL;
 213  did_not_get_any_errors:
 214
 215         if (buffer)
 216                 free(buffer);
 217
 218         if (gif)
 219                 DGifCloseFile(gif);
 220
 221         return image;
 222 }