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 #include "wr_i18n.h"
  34
  35
  36 static int InterlacedOffset[] = { 0, 4, 2, 1 };
  37 static int InterlacedJumps[] = { 8, 8, 4, 2 };
  38
  39 /*
  40  * Partially based on code in gif2rgb from giflib, by Gershon Elber.
  41  */
  42 RImage *RLoadGIF(const char *file, int index)
  43 {
  44         RImage *image = NULL;
  45         unsigned char *cptr;
  46         GifFileType *gif = NULL;
  47         GifPixelType *buffer = NULL;
  48         int i, j, k;
  49         int width, height;
  50         GifRecordType recType;
  51         ColorMapObject *colormap;
  52         unsigned char rmap[256], gmap[256], bmap[256];
  53         int gif_error;
  54
  55         if (index < 0)
  56                 index = 0;
  57
  58         /* default error message */
  59         RErrorCode = RERR_BADINDEX;
  60
  61 #if USE_GIF == 4
  62         gif = DGifOpenFileName(file);
  63 #else /* USE_GIF == 5 */
  64         gif = DGifOpenFileName(file, &gif_error);
  65 #endif
  66
  67         if (!gif) {
  68 #if USE_GIF == 4
  69                 gif_error = GifLastError();
  70 #endif
  71                 switch (gif_error) {
  72                 case D_GIF_ERR_OPEN_FAILED:
  73                         RErrorCode = RERR_OPEN;
  74                         break;
  75                 case D_GIF_ERR_READ_FAILED:
  76                         RErrorCode = RERR_READ;
  77                         break;
  78                 default:
  79                         RErrorCode = RERR_BADIMAGEFILE;
  80                         break;
  81                 }
  82                 return NULL;
  83         }
  84
  85         if (gif->SWidth < 1 || gif->SHeight < 1) {
  86 #if (USE_GIF == 5) && (GIFLIB_MINOR >= 1)
  87                 DGifCloseFile(gif, NULL);
  88 #else
  89                 DGifCloseFile(gif);
  90 #endif
  91                 RErrorCode = RERR_BADIMAGEFILE;
  92                 return NULL;
  93         }
  94
  95         colormap = gif->SColorMap;
  96         i = 0;
  97
  98         do {
  99                 int extCode;
 100                 GifByteType *extension;
 101
 102                 if (DGifGetRecordType(gif, &recType) == GIF_ERROR)
 103                         goto giferr;
 104
 105                 switch (recType) {
 106                 case IMAGE_DESC_RECORD_TYPE:
 107                         if (i++ != index)
 108                                 break;
 109
 110                         if (DGifGetImageDesc(gif) == GIF_ERROR)
 111                                 goto giferr;
 112
 113                         width = gif->Image.Width;
 114                         height = gif->Image.Height;
 115
 116                         if (gif->Image.ColorMap)
 117                                 colormap = gif->Image.ColorMap;
 118
 119                         /* the gif specs talk about a default colormap, but it
 120                          * doesnt say what the heck is this default colormap
 121                          * Render anything */
 122                         if (colormap) {
 123                                 for (j = 0; j < colormap->ColorCount; j++) {
 124                                         rmap[j] = colormap->Colors[j].Red;
 125                                         gmap[j] = colormap->Colors[j].Green;
 126                                         bmap[j] = colormap->Colors[j].Blue;
 127                                 }
 128                         }
 129
 130                         buffer = malloc(width * sizeof(GifPixelType));
 131                         if (!buffer) {
 132                                 RErrorCode = RERR_NOMEMORY;
 133                                 goto bye;
 134                         }
 135
 136                         image = RCreateImage(width, height, False);
 137                         if (!image)
 138                                 goto bye;
 139
 140                         if (gif->Image.Interlace) {
 141                                 int l, pelsPerLine;
 142
 143                                 if (RRGBAFormat == image->format)
 144                                         pelsPerLine = width * 4;
 145                                 else
 146                                         pelsPerLine = width * 3;
 147
 148                                 for (j = 0; j < 4; j++) {
 149                                         for (k = InterlacedOffset[j]; k < height; k += InterlacedJumps[j]) {
 150                                                 if (DGifGetLine(gif, buffer, width) == GIF_ERROR)
 151                                                         goto giferr;
 152
 153                                                 cptr = image->data + (k * pelsPerLine);
 154                                                 for (l = 0; l < width; l++) {
 155                                                         int pixel = buffer[l];
 156                                                         *cptr++ = rmap[pixel];
 157                                                         *cptr++ = gmap[pixel];
 158                                                         *cptr++ = bmap[pixel];
 159                                                 }
 160                                         }
 161                                 }
 162                         } else {
 163                                 cptr = image->data;
 164                                 for (j = 0; j < height; j++) {
 165                                         if (DGifGetLine(gif, buffer, width) == GIF_ERROR)
 166                                                 goto giferr;
 167
 168                                         for (k = 0; k < width; k++) {
 169                                                 int pixel = buffer[k];
 170                                                 *cptr++ = rmap[pixel];
 171                                                 *cptr++ = gmap[pixel];
 172                                                 *cptr++ = bmap[pixel];
 173                                                 if (RRGBAFormat == image->format)
 174                                                         cptr++;
 175                                         }
 176                                 }
 177                         }
 178                         break;
 179
 180                 case EXTENSION_RECORD_TYPE:
 181                         /* skip all extension blocks */
 182                         if (DGifGetExtension(gif, &extCode, &extension) == GIF_ERROR)
 183                                 goto giferr;
 184
 185                         while (extension)
 186                                 if (DGifGetExtensionNext(gif, &extension) == GIF_ERROR)
 187                                         goto giferr;
 188
 189                         break;
 190
 191                 default:
 192                         break;
 193                 }
 194         } while (recType != TERMINATE_RECORD_TYPE && i <= index);
 195
 196         /* yuck! */
 197         goto did_not_get_any_errors;
 198  giferr:
 199 #if USE_GIF == 4
 200         switch (GifLastError()) {
 201         case D_GIF_ERR_OPEN_FAILED:
 202                 RErrorCode = RERR_OPEN;
 203                 break;
 204         case D_GIF_ERR_READ_FAILED:
 205                 RErrorCode = RERR_READ;
 206                 break;
 207         default:
 208                 RErrorCode = RERR_BADIMAGEFILE;
 209                 break;
 210         }
 211 #else
 212         /* With gif_lib v5 there's no way to know what went wrong */
 213         RErrorCode = RERR_BADIMAGEFILE;
 214 #endif
 215  bye:
 216         if (image)
 217                 RReleaseImage(image);
 218         image = NULL;
 219  did_not_get_any_errors:
 220
 221         if (buffer)
 222                 free(buffer);
 223
 224         if (gif)
 225 #if (USE_GIF == 5) && (GIFLIB_MINOR >= 1)
 226                 DGifCloseFile(gif, NULL);
 227 #else
 228                 DGifCloseFile(gif);
 229 #endif
 230
 231         return image;
 232 }