images/io-libungif.c

   1 /*
   2  *      Image Library -- libungif
   3  *
   4  *      (c) 2006 Pavel Charvat <pchar@ucw.cz>
   5  *
   6  *      This software may be freely distributed and used according to the terms
   7  *      of the GNU Lesser General Public License.
   8  */
   9
  10 #undef LOCAL_DEBUG
  11
  12 #include <ucw/lib.h>
  13 #include <ucw/mempool.h>
  14 #include <ucw/fastbuf.h>
  15 #include <images/images.h>
  16 #include <images/error.h>
  17 #include <images/color.h>
  18 #include <images/io-main.h>
  19
  20 #include <gif_lib.h>
  21
  22 struct libungif_read_data {
  23   GifFileType *gif;
  24   int transparent_index;
  25 };
  26
  27 static int
  28 libungif_read_func(GifFileType *gif, GifByteType *ptr, int len)
  29 {
  30   DBG("libungif_read_func(len=%d)", len);
  31   return bread((struct fastbuf *)gif->UserData, (byte *)ptr, len);
  32 }
  33
  34 static void
  35 libungif_read_cancel(struct image_io *io)
  36 {
  37   DBG("libungif_read_cancel()");
  38
  39   struct libungif_read_data *rd = io->read_data;
  40   DGifCloseFile(rd->gif);
  41 }
  42
  43 int
  44 libungif_read_header(struct image_io *io)
  45 {
  46   DBG("libungif_read_header()");
  47
  48   /* Create libungif structure */
  49   GifFileType *gif;
  50   if (unlikely(!(gif = DGifOpen(io->fastbuf, libungif_read_func))))
  51     {
  52       IMAGE_ERROR(io->context, IMAGE_ERROR_READ_FAILED, "Cannot create libungif structure.");
  53       return 0;
  54     }
  55
  56   struct libungif_read_data *rd = io->read_data = mp_alloc(io->internal_pool, sizeof(*rd));
  57   rd->gif = gif;
  58
  59   DBG("executing DGifSlurp()");
  60   if (unlikely(DGifSlurp(gif) != GIF_OK))
  61     {
  62       IMAGE_ERROR(io->context, IMAGE_ERROR_READ_FAILED, "Gif read failed.");
  63       DGifCloseFile(gif);
  64       return 0;
  65     }
  66
  67   DBG("ImageCount=%d ColorResolution=%d SBackGroundColor=%d SColorMap=%p", gif->ImageCount, gif->SColorResolution, gif->SBackGroundColor, gif->SColorMap);
  68   if (unlikely(!gif->ImageCount))
  69     {
  70       IMAGE_ERROR(io->context, IMAGE_ERROR_READ_FAILED, "There are no images in gif file.");
  71       DGifCloseFile(gif);
  72       return 0;
  73     }
  74
  75   /* Read image parameters */
  76   SavedImage *image = gif->SavedImages;
  77   if (unlikely(image->ImageDesc.Width <= 0 || image->ImageDesc.Height <= 0 ||
  78       image->ImageDesc.Width > (int)image_max_dim || image->ImageDesc.Height > (int)image_max_dim))
  79     {
  80       IMAGE_ERROR(io->context, IMAGE_ERROR_INVALID_DIMENSIONS, "Invalid gif dimensions.");
  81       DGifCloseFile(gif);
  82       return 0;
  83     }
  84   ColorMapObject *color_map = image->ImageDesc.ColorMap ? : gif->SColorMap;
  85   if (unlikely(!color_map))
  86     {
  87       IMAGE_ERROR(io->context, IMAGE_ERROR_READ_FAILED, "Missing palette.");
  88       DGifCloseFile(gif);
  89       return 0;
  90     }
  91   io->cols = image->ImageDesc.Width;
  92   io->rows = image->ImageDesc.Height;
  93   if (unlikely((io->number_of_colors = color_map->ColorCount) > 256))
  94     {
  95       IMAGE_ERROR(io->context, IMAGE_ERROR_READ_FAILED, "Too many gif colors.");
  96       DGifCloseFile(gif);
  97       return 0;
  98     }
  99   io->flags = COLOR_SPACE_RGB | IMAGE_IO_HAS_PALETTE;
 100
 101   /* Search extension blocks */
 102   rd->transparent_index = -1;
 103   for (int i = 0; i < image->ExtensionBlockCount; i++)
 104     {
 105       ExtensionBlock *e = image->ExtensionBlocks + i;
 106       if (e->Function == 0xF9)
 107         {
 108           DBG("Found graphics control extension");
 109           if (unlikely(e->ByteCount != 4))
 110             {
 111               IMAGE_ERROR(io->context, IMAGE_ERROR_READ_FAILED, "Invalid graphics control extension.");
 112               DGifCloseFile(gif);
 113               return 0;
 114             }
 115           byte *b = e->Bytes;
 116           /* transparent color present */
 117           if (b[0] & 1)
 118             {
 119               rd->transparent_index = b[3];
 120               io->flags |= IMAGE_ALPHA;
 121               if (gif->SColorMap)
 122                 {
 123                   GifColorType *background = color_map->Colors + gif->SBackGroundColor;
 124                   color_make_rgb(&io->background_color, background->Red, background->Green, background->Blue);
 125                 }
 126             }
 127           /* We've got everything we need :-) */
 128           break;
 129         }
 130       else
 131         DBG("Found unknown extension: type=%d size=%d", e->Function, e->ByteCount);
 132     }
 133
 134   /* Success */
 135   io->read_cancel = libungif_read_cancel;
 136   return 1;
 137 }
 138
 139 int
 140 libungif_read_data(struct image_io *io)
 141 {
 142   DBG("libungif_read_data()");
 143
 144   struct libungif_read_data *rd = io->read_data;
 145   GifFileType *gif = rd->gif;
 146   SavedImage *image = gif->SavedImages;
 147
 148   /* Prepare image */
 149   struct image_io_read_data_internals rdi;
 150   uns read_flags = io->flags;
 151   uns cs = read_flags & IMAGE_COLOR_SPACE;
 152   if (cs != COLOR_SPACE_GRAYSCALE && cs != COLOR_SPACE_RGB)
 153     read_flags = (read_flags & ~IMAGE_COLOR_SPACE & IMAGE_CHANNELS_FORMAT) | COLOR_SPACE_RGB;
 154   if (unlikely(!image_io_read_data_prepare(&rdi, io, image->ImageDesc.Width, image->ImageDesc.Height, read_flags)))
 155     {
 156       DGifCloseFile(gif);
 157       return 0;
 158     }
 159
 160   /* Get pixels and palette */
 161   byte *pixels = (byte *)image->RasterBits;
 162   ColorMapObject *color_map = image->ImageDesc.ColorMap ? : gif->SColorMap;
 163   GifColorType *palette = color_map->Colors;
 164   byte *img_end = rdi.image->pixels + rdi.image->image_size;
 165
 166   /* Handle deinterlacing */
 167   uns dein_step, dein_next;
 168   if (image->ImageDesc.Interlace)
 169     {
 170       DBG("Deinterlaced image");
 171       dein_step = dein_next = rdi.image->row_size << 3;
 172     }
 173   else
 174     dein_step = dein_next = rdi.image->row_size;
 175
 176   /* Convert pixels */
 177   switch (rdi.image->pixel_size)
 178     {
 179       case 1:
 180         {
 181           byte pal[256], *pal_pos = pal, *pal_end = pal + 256;
 182           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos++, palette++)
 183             *pal_pos = rgb_to_gray_func(palette->Red, palette->Green, palette->Blue);
 184           if (pal_pos != pal_end)
 185             bzero(pal_pos, pal_end - pal_pos);
 186           if (rd->transparent_index >= 0 && (io->flags & IMAGE_IO_USE_BACKGROUND))
 187             if (!color_put(io->context, &io->background_color, pal + rd->transparent_index, COLOR_SPACE_GRAYSCALE))
 188               {
 189                 DGifCloseFile(gif);
 190                 return 0;
 191               }
 192 #         define DO_ROW_END do{ \
 193               walk_row_start += dein_step; \
 194               while (walk_row_start >= img_end) \
 195                 { uns n = dein_next >> 1; walk_row_start = rdi.image->pixels + n, dein_step = dein_next; dein_next = n; } \
 196             }while(0)
 197 #         define IMAGE_WALK_PREFIX(x) walk_##x
 198 #         define IMAGE_WALK_INLINE
 199 #         define IMAGE_WALK_IMAGE (rdi.image)
 200 #         define IMAGE_WALK_UNROLL 4
 201 #         define IMAGE_WALK_COL_STEP 1
 202 #         define IMAGE_WALK_ROW_STEP 0
 203 #         define IMAGE_WALK_DO_STEP do{ *walk_pos = pal[*pixels++]; }while(0)
 204 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 205 #         include <images/image-walk.h>
 206           break;
 207         }
 208       case 2:
 209         {
 210           byte pal[256 * 2], *pal_pos = pal, *pal_end = pal + 256 * 2;
 211           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos += 2, palette++)
 212             {
 213               pal_pos[0] = rgb_to_gray_func(palette->Red, palette->Green, palette->Blue);
 214               pal_pos[1] = 255;
 215             }
 216           if (pal_pos != pal_end)
 217             bzero(pal_pos, pal_end - pal_pos);
 218           if (rd->transparent_index >= 0)
 219             pal[rd->transparent_index * 2 + 1] = 0;
 220 #         define IMAGE_WALK_PREFIX(x) walk_##x
 221 #         define IMAGE_WALK_INLINE
 222 #         define IMAGE_WALK_IMAGE (rdi.image)
 223 #         define IMAGE_WALK_UNROLL 4
 224 #         define IMAGE_WALK_COL_STEP 2
 225 #         define IMAGE_WALK_ROW_STEP 0
 226 #         define IMAGE_WALK_DO_STEP do{ *(u16 *)walk_pos = ((u16 *)pal)[*pixels++]; }while(0)
 227 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 228 #         include <images/image-walk.h>
 229           break;
 230         }
 231       case 3:
 232         {
 233           byte pal[256 * 4], *pal_pos = pal, *pal_end = pal + 256 * 4;
 234           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos += 4, palette++)
 235             {
 236               pal_pos[0] = palette->Red;
 237               pal_pos[1] = palette->Green;
 238               pal_pos[2] = palette->Blue;
 239             }
 240           if (pal_pos != pal_end)
 241             bzero(pal_pos, pal_end - pal_pos);
 242           if (rd->transparent_index >= 0 && (io->flags & IMAGE_IO_USE_BACKGROUND))
 243             if (!color_put(io->context, &io->background_color, pal + 4 * rd->transparent_index, COLOR_SPACE_RGB))
 244               {
 245                 DGifCloseFile(gif);
 246                 return 0;
 247               }
 248 #         define IMAGE_WALK_PREFIX(x) walk_##x
 249 #         define IMAGE_WALK_INLINE
 250 #         define IMAGE_WALK_IMAGE (rdi.image)
 251 #         define IMAGE_WALK_UNROLL 4
 252 #         define IMAGE_WALK_COL_STEP 3
 253 #         define IMAGE_WALK_ROW_STEP 0
 254 #         define IMAGE_WALK_DO_STEP do{ byte *p = pal + 4 * (*pixels++); walk_pos[0] = p[0]; walk_pos[1] = p[1]; walk_pos[2] = p[2]; }while(0)
 255 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 256 #         include <images/image-walk.h>
 257           break;
 258         }
 259       case 4:
 260         {
 261           byte pal[256 * 4], *pal_pos = pal, *pal_end = pal + 256 * 4;
 262           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos += 4, palette++)
 263             {
 264               pal_pos[0] = palette->Red;
 265               pal_pos[1] = palette->Green;
 266               pal_pos[2] = palette->Blue;
 267               pal_pos[3] = 255;
 268             }
 269           if (pal_pos != pal_end)
 270             bzero(pal_pos, pal_end - pal_pos);
 271           if (rd->transparent_index >= 0)
 272             pal[rd->transparent_index * 4 + 3] = 0;
 273 #         define IMAGE_WALK_PREFIX(x) walk_##x
 274 #         define IMAGE_WALK_INLINE
 275 #         define IMAGE_WALK_IMAGE (rdi.image)
 276 #         define IMAGE_WALK_UNROLL 4
 277 #         define IMAGE_WALK_COL_STEP 4
 278 #         define IMAGE_WALK_ROW_STEP 0
 279 #         define IMAGE_WALK_DO_STEP do{ *(u32 *)walk_pos = ((u32 *)pal)[*pixels++]; }while(0)
 280 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 281 #         include <images/image-walk.h>
 282           break;
 283         }
 284       default:
 285         ASSERT(0);
 286     }
 287
 288   /* Destroy libungif structure */
 289   DGifCloseFile(gif);
 290
 291   /* Finish image */
 292   return image_io_read_data_finish(&rdi, io);
 293 }