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 #if (USE_GIF == 5) && (GIFLIB_MINOR >= 1)
  85                 DGifCloseFile(gif, NULL);
  86 #else
  87                 DGifCloseFile(gif);
  88 #endif
  89                 RErrorCode = RERR_BADIMAGEFILE;
  90                 return NULL;
  91         }
  92
  93         colormap = gif->SColorMap;
  94         i = 0;
  95
  96         do {
  97                 int extCode;
  98                 GifByteType *extension;
  99
 100                 if (DGifGetRecordType(gif, &recType) == GIF_ERROR)
 101                         goto giferr;
 102
 103                 switch (recType) {
 104                 case IMAGE_DESC_RECORD_TYPE:
 105                         if (i++ != index)
 106                                 break;
 107
 108                         if (DGifGetImageDesc(gif) == GIF_ERROR)
 109                                 goto giferr;
 110
 111                         width = gif->Image.Width;
 112                         height = gif->Image.Height;
 113
 114                         if (gif->Image.ColorMap)
 115                                 colormap = gif->Image.ColorMap;
 116
 117                         /* the gif specs talk about a default colormap, but it
 118                          * doesnt say what the heck is this default colormap
 119                          * Render anything */
 120                         if (colormap) {
 121                                 for (j = 0; j < colormap->ColorCount; j++) {
 122                                         rmap[j] = colormap->Colors[j].Red;
 123                                         gmap[j] = colormap->Colors[j].Green;
 124                                         bmap[j] = colormap->Colors[j].Blue;
 125                                 }
 126                         }
 127
 128                         buffer = malloc(width * sizeof(GifPixelType));
 129                         if (!buffer) {
 130                                 RErrorCode = RERR_NOMEMORY;
 131                                 goto bye;
 132                         }
 133
 134                         image = RCreateImage(width, height, False);
 135                         if (!image)
 136                                 goto bye;
 137
 138                         if (gif->Image.Interlace) {
 139                                 int l, pelsPerLine;
 140
 141                                 if (RRGBAFormat == image->format)
 142                                         pelsPerLine = width * 4;
 143                                 else
 144                                         pelsPerLine = width * 3;
 145
 146                                 for (j = 0; j < 4; j++) {
 147                                         for (k = InterlacedOffset[j]; k < height; k += InterlacedJumps[j]) {
 148                                                 if (DGifGetLine(gif, buffer, width) == GIF_ERROR)
 149                                                         goto giferr;
 150
 151                                                 cptr = image->data + (k * pelsPerLine);
 152                                                 for (l = 0; l < width; l++) {
 153                                                         int pixel = buffer[l];
 154                                                         *cptr++ = rmap[pixel];
 155                                                         *cptr++ = gmap[pixel];
 156                                                         *cptr++ = bmap[pixel];
 157                                                 }
 158                                         }
 159                                 }
 160                         } else {
 161                                 cptr = image->data;
 162                                 for (j = 0; j < height; j++) {
 163                                         if (DGifGetLine(gif, buffer, width) == GIF_ERROR)
 164                                                 goto giferr;
 165
 166                                         for (k = 0; k < width; k++) {
 167                                                 int pixel = buffer[k];
 168                                                 *cptr++ = rmap[pixel];
 169                                                 *cptr++ = gmap[pixel];
 170                                                 *cptr++ = bmap[pixel];
 171                                                 if (RRGBAFormat == image->format)
 172                                                         cptr++;
 173                                         }
 174                                 }
 175                         }
 176                         break;
 177
 178                 case EXTENSION_RECORD_TYPE:
 179                         /* skip all extension blocks */
 180                         if (DGifGetExtension(gif, &extCode, &extension) == GIF_ERROR)
 181                                 goto giferr;
 182
 183                         while (extension)
 184                                 if (DGifGetExtensionNext(gif, &extension) == GIF_ERROR)
 185                                         goto giferr;
 186
 187                         break;
 188
 189                 default:
 190                         break;
 191                 }
 192         } while (recType != TERMINATE_RECORD_TYPE && i <= index);
 193
 194         /* yuck! */
 195         goto did_not_get_any_errors;
 196  giferr:
 197 #if USE_GIF == 4
 198         switch (GifLastError()) {
 199         case D_GIF_ERR_OPEN_FAILED:
 200                 RErrorCode = RERR_OPEN;
 201                 break;
 202         case D_GIF_ERR_READ_FAILED:
 203                 RErrorCode = RERR_READ;
 204                 break;
 205         default:
 206                 RErrorCode = RERR_BADIMAGEFILE;
 207                 break;
 208         }
 209 #else
 210         /* With gif_lib v5 there's no way to know what went wrong */
 211         RErrorCode = RERR_BADIMAGEFILE;
 212 #endif
 213  bye:
 214         if (image)
 215                 RReleaseImage(image);
 216         image = NULL;
 217  did_not_get_any_errors:
 218
 219         if (buffer)
 220                 free(buffer);
 221
 222         if (gif)
 223 #if (USE_GIF == 5) && (GIFLIB_MINOR >= 1)
 224                 DGifCloseFile(gif, NULL);
 225 #else
 226                 DGifCloseFile(gif);
 227 #endif
 228
 229         return image;
 230 }