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 "lib/lib.h"
  13 #include "lib/mempool.h"
  14 #include "lib/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   if (unlikely(!image_io_read_data_prepare(&rdi, io, image->ImageDesc.Width, image->ImageDesc.Height, io->flags)))
 151     {
 152       DGifCloseFile(gif);
 153       return 0;
 154     }
 155
 156   /* Get pixels and palette */
 157   byte *pixels = (byte *)image->RasterBits;
 158   ColorMapObject *color_map = image->ImageDesc.ColorMap ? : gif->SColorMap;
 159   GifColorType *palette = color_map->Colors;
 160   byte *img_end = rdi.image->pixels + rdi.image->image_size;
 161
 162   /* Handle deinterlacing */
 163   uns dein_step, dein_next;
 164   if (image->ImageDesc.Interlace)
 165     {
 166       DBG("Deinterlaced image");
 167       dein_step = dein_next = rdi.image->row_size << 3;
 168     }
 169   else
 170     dein_step = dein_next = rdi.image->row_size;
 171
 172   /* Convert pixels */
 173   switch (rdi.image->pixel_size)
 174     {
 175       case 1:
 176         {
 177           byte pal[256], *pal_pos = pal, *pal_end = pal + 256;
 178           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos++, palette++)
 179             *pal_pos = rgb_to_gray_func(palette->Red, palette->Green, palette->Blue);
 180           if (pal_pos != pal_end)
 181             bzero(pal_pos, pal_end - pal_pos);
 182           if (rd->transparent_index >= 0 && (io->flags & IMAGE_IO_USE_BACKGROUND))
 183             color_put_grayscale(pal + rd->transparent_index, &io->background_color);
 184 #         define DO_ROW_END do{ \
 185               walk_row_start += dein_step; \
 186               if (walk_row_start >= img_end) \
 187                 { uns n = dein_next >> 1; walk_row_start = rdi.image->pixels + n, dein_step = dein_next; dein_next = n; } \
 188             }while(0)
 189 #         define IMAGE_WALK_PREFIX(x) walk_##x
 190 #         define IMAGE_WALK_INLINE
 191 #         define IMAGE_WALK_IMAGE (rdi.image)
 192 #         define IMAGE_WALK_UNROLL 4
 193 #         define IMAGE_WALK_COL_STEP 1
 194 #         define IMAGE_WALK_ROW_STEP 0
 195 #         define IMAGE_WALK_DO_STEP do{ *walk_pos = pal[*pixels++]; }while(0)
 196 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 197 #         include "images/image-walk.h"
 198           break;
 199         }
 200       case 2:
 201         {
 202           byte pal[256 * 2], *pal_pos = pal, *pal_end = pal + 256 * 2;
 203           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos += 2, palette++)
 204             {
 205               pal_pos[0] = rgb_to_gray_func(palette->Red, palette->Green, palette->Blue);
 206               pal_pos[1] = 255;
 207             }
 208           if (pal_pos != pal_end)
 209             bzero(pal_pos, pal_end - pal_pos);
 210           if (rd->transparent_index >= 0)
 211             pal[rd->transparent_index * 2 + 1] = 0;
 212 #         define IMAGE_WALK_PREFIX(x) walk_##x
 213 #         define IMAGE_WALK_INLINE
 214 #         define IMAGE_WALK_IMAGE (rdi.image)
 215 #         define IMAGE_WALK_UNROLL 4
 216 #         define IMAGE_WALK_COL_STEP 2
 217 #         define IMAGE_WALK_ROW_STEP 0
 218 #         define IMAGE_WALK_DO_STEP do{ *(u16 *)walk_pos = ((u16 *)pal)[*pixels++]; }while(0)
 219 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 220 #         include "images/image-walk.h"
 221           break;
 222         }
 223       case 3:
 224         {
 225           byte pal[256 * 4], *pal_pos = pal, *pal_end = pal + 256 * 4;
 226           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos += 4, palette++)
 227             {
 228               pal_pos[0] = palette->Red;
 229               pal_pos[1] = palette->Green;
 230               pal_pos[2] = palette->Blue;
 231             }
 232           if (pal_pos != pal_end)
 233             bzero(pal_pos, pal_end - pal_pos);
 234           if (rd->transparent_index >= 0 && (io->flags & IMAGE_IO_USE_BACKGROUND))
 235             color_put_rgb(pal + 4 * rd->transparent_index, &io->background_color);
 236 #         define IMAGE_WALK_PREFIX(x) walk_##x
 237 #         define IMAGE_WALK_INLINE
 238 #         define IMAGE_WALK_IMAGE (rdi.image)
 239 #         define IMAGE_WALK_UNROLL 4
 240 #         define IMAGE_WALK_COL_STEP 3
 241 #         define IMAGE_WALK_ROW_STEP 0
 242 #         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)
 243 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 244 #         include "images/image-walk.h"
 245           break;
 246         }
 247       case 4:
 248         {
 249           byte pal[256 * 4], *pal_pos = pal, *pal_end = pal + 256 * 4;
 250           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos += 4, palette++)
 251             {
 252               pal_pos[0] = palette->Red;
 253               pal_pos[1] = palette->Green;
 254               pal_pos[2] = palette->Blue;
 255               pal_pos[3] = 255;
 256             }
 257           if (pal_pos != pal_end)
 258             bzero(pal_pos, pal_end - pal_pos);
 259           if (rd->transparent_index >= 0)
 260             pal[rd->transparent_index * 4 + 3] = 0;
 261 #         define IMAGE_WALK_PREFIX(x) walk_##x
 262 #         define IMAGE_WALK_INLINE
 263 #         define IMAGE_WALK_IMAGE (rdi.image)
 264 #         define IMAGE_WALK_UNROLL 4
 265 #         define IMAGE_WALK_COL_STEP 4
 266 #         define IMAGE_WALK_ROW_STEP 0
 267 #         define IMAGE_WALK_DO_STEP do{ *(u32 *)walk_pos = ((u32 *)pal)[*pixels++]; }while(0)
 268 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 269 #         include "images/image-walk.h"
 270           break;
 271         }
 272       default:
 273         ASSERT(0);
 274     }
 275
 276   /* Destroy libungif structure */
 277   DGifCloseFile(gif);
 278
 279   /* Finish image */
 280   return image_io_read_data_finish(&rdi, io);
 281 }