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/io-main.h"
  17 #include <gif_lib.h>
  18
  19 static int
  20 libungif_read_func(GifFileType *gif, GifByteType *ptr, int len)
  21 {
  22   DBG("libungif_read_func(len=%d)", len);
  23   return bread((struct fastbuf *)gif->UserData, (byte *)ptr, len);
  24 }
  25
  26 static void
  27 libungif_read_cancel(struct image_io *io)
  28 {
  29   DBG("libungif_read_cancel()");
  30
  31   DGifCloseFile(io->read_data);
  32 }
  33
  34 int
  35 libungif_read_header(struct image_io *io)
  36 {
  37   DBG("libungif_read_header()");
  38
  39   /* Create libungif structure */
  40   GifFileType *gif;
  41   if (unlikely(!(gif = io->read_data = DGifOpen(io->fastbuf, libungif_read_func))))
  42     {
  43       image_thread_err(io->thread, IMAGE_ERR_READ_FAILED, "Cannot create libungif structure.");
  44       return 0;
  45     }
  46
  47   if (unlikely(DGifSlurp(gif) != GIF_OK))
  48     {
  49       image_thread_err(io->thread, IMAGE_ERR_READ_FAILED, "Gif read failed.");
  50       DGifCloseFile(gif);
  51       return 0;
  52     }
  53
  54   if (unlikely(!gif->ImageCount))
  55     {
  56       image_thread_err(io->thread, IMAGE_ERR_READ_FAILED, "There are no images in gif file.");
  57       DGifCloseFile(gif);
  58       return 0;
  59     }
  60
  61   /* Read image parameters */
  62   SavedImage *image = gif->SavedImages;
  63   if (unlikely(image->ImageDesc.Width <= 0 || image->ImageDesc.Height <= 0 ||
  64       image->ImageDesc.Width > (int)IMAGE_MAX_SIZE || image->ImageDesc.Height > (int)IMAGE_MAX_SIZE))
  65     {
  66       image_thread_err(io->thread, IMAGE_ERR_INVALID_DIMENSIONS, "Invalid gif dimensions.");
  67       DGifCloseFile(gif);
  68       return 0;
  69     }
  70   ColorMapObject *color_map = image->ImageDesc.ColorMap ? : gif->SColorMap;
  71   if (unlikely(!color_map))
  72     {
  73       image_thread_err(io->thread, IMAGE_ERR_READ_FAILED, "Missing palette.");
  74       DGifCloseFile(gif);
  75       return 0;
  76     }
  77   io->cols = image->ImageDesc.Width;
  78   io->rows = image->ImageDesc.Height;
  79   io->number_of_colors = color_map->ColorCount;
  80   io->flags = COLOR_SPACE_RGB | IMAGE_IO_HAS_PALETTE;
  81   if ((uns)gif->SBackGroundColor < (uns)color_map->ColorCount)
  82     io->flags |= IMAGE_ALPHA;
  83
  84   /* Success */
  85   io->read_cancel = libungif_read_cancel;
  86   return 1;
  87 }
  88
  89 static inline byte
  90 libungif_pixel_to_gray(GifColorType *pixel)
  91 {
  92   return ((uns)pixel->Red * 19660 + (uns)pixel->Green * 38666 + (uns)pixel->Blue * 7210) >> 16;
  93 }
  94
  95 int
  96 libungif_read_data(struct image_io *io)
  97 {
  98   DBG("libungif_read_data()");
  99
 100   GifFileType *gif = io->read_data;
 101   SavedImage *image = gif->SavedImages;
 102
 103   /* Prepare image */
 104   struct image_io_read_data_internals rdi;
 105   if (unlikely(!image_io_read_data_prepare(&rdi, io, image->ImageDesc.Width, image->ImageDesc.Height)))
 106     {
 107       DGifCloseFile(gif);
 108       return 0;
 109     }
 110
 111   /* Get pixels and palette */
 112   byte *pixels = (byte *)image->RasterBits;
 113   ColorMapObject *color_map = image->ImageDesc.ColorMap ? : gif->SColorMap;
 114   GifColorType *palette = color_map->Colors;
 115   uns background = gif->SBackGroundColor;
 116   byte *img_end = rdi.image->pixels + rdi.image->image_size;
 117
 118   /* Handle deinterlacing */
 119   uns dein_step, dein_next;
 120   if (image->ImageDesc.Interlace)
 121     dein_step = dein_next = rdi.image->row_size << 3;
 122   else
 123     dein_step = dein_next = rdi.image->row_size;
 124
 125   /* Convert pixels */
 126   switch (rdi.image->pixel_size)
 127     {
 128       case 1:
 129         {
 130           byte pal[256], *pal_pos = pal, *pal_end = pal + 256;
 131           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos++, palette++)
 132             *pal_pos = libungif_pixel_to_gray(palette);
 133           if (pal_pos != pal_end)
 134             bzero(pal_pos, pal_end - pal_pos);
 135 #         define DO_ROW_END do{ \
 136               walk_row_start += dein_step; \
 137               if (walk_row_start > img_end) \
 138                 { uns n = dein_next >> 1; walk_row_start = rdi.image->pixels + n, dein_step = dein_next; dein_next = n; } \
 139             }while(0)
 140 #         define IMAGE_WALK_PREFIX(x) walk_##x
 141 #         define IMAGE_WALK_INLINE
 142 #         define IMAGE_WALK_IMAGE (rdi.image)
 143 #         define IMAGE_WALK_UNROLL 4
 144 #         define IMAGE_WALK_COL_STEP 1
 145 #         define IMAGE_WALK_ROW_STEP 0
 146 #         define IMAGE_WALK_DO_STEP do{ *walk_pos = pal[*pixels++]; }while(0)
 147 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 148 #         include "images/image-walk.h"
 149           break;
 150         }
 151       case 2:
 152         {
 153           byte pal[256 * 2], *pal_pos = pal, *pal_end = pal + 256 * 2;
 154           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos += 2, palette++)
 155             {
 156               pal_pos[0] = libungif_pixel_to_gray(palette);
 157               pal_pos[1] = 255;
 158             }
 159           if (pal_pos != pal_end)
 160             bzero(pal_pos, pal_end - pal_pos);
 161           if (background < 256)
 162             pal[background * 2 + 1] = 0;
 163 #         define IMAGE_WALK_PREFIX(x) walk_##x
 164 #         define IMAGE_WALK_INLINE
 165 #         define IMAGE_WALK_IMAGE (rdi.image)
 166 #         define IMAGE_WALK_UNROLL 4
 167 #         define IMAGE_WALK_COL_STEP 2
 168 #         define IMAGE_WALK_ROW_STEP 0
 169 #         define IMAGE_WALK_DO_STEP do{ *(u16 *)walk_pos = ((u16 *)pal)[*pixels++]; }while(0)
 170 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 171 #         include "images/image-walk.h"
 172           break;
 173         }
 174       case 3:
 175         {
 176           byte pal[256 * 4], *pal_pos = pal, *pal_end = pal + 256 * 4;
 177           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos += 4, palette++)
 178             {
 179               pal_pos[0] = palette->Red;
 180               pal_pos[1] = palette->Green;
 181               pal_pos[2] = palette->Blue;
 182             }
 183           if (pal_pos != pal_end)
 184             bzero(pal_pos, pal_end - pal_pos);
 185 #         define IMAGE_WALK_PREFIX(x) walk_##x
 186 #         define IMAGE_WALK_INLINE
 187 #         define IMAGE_WALK_IMAGE (rdi.image)
 188 #         define IMAGE_WALK_UNROLL 4
 189 #         define IMAGE_WALK_COL_STEP 3
 190 #         define IMAGE_WALK_ROW_STEP 0
 191 #         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)
 192 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 193 #         include "images/image-walk.h"
 194           break;
 195         }
 196       case 4:
 197         {
 198           byte pal[256 * 4], *pal_pos = pal, *pal_end = pal + 256 * 4;
 199           for (uns i = 0; i < (uns)color_map->ColorCount; i++, pal_pos += 4, palette++)
 200             {
 201               pal_pos[0] = palette->Red;
 202               pal_pos[1] = palette->Green;
 203               pal_pos[2] = palette->Blue;
 204               pal_pos[3] = 255;
 205             }
 206           if (pal_pos != pal_end)
 207             bzero(pal_pos, pal_end - pal_pos);
 208           if (background < 256)
 209             pal[background * 4 + 3] = 0;
 210 #         define IMAGE_WALK_PREFIX(x) walk_##x
 211 #         define IMAGE_WALK_INLINE
 212 #         define IMAGE_WALK_IMAGE (rdi.image)
 213 #         define IMAGE_WALK_UNROLL 4
 214 #         define IMAGE_WALK_COL_STEP 4
 215 #         define IMAGE_WALK_ROW_STEP 0
 216 #         define IMAGE_WALK_DO_STEP do{ *(u32 *)walk_pos = ((u32 *)pal)[*pixels++]; }while(0)
 217 #         define IMAGE_WALK_DO_ROW_END DO_ROW_END
 218 #         include "images/image-walk.h"
 219           break;
 220         }
 221       default:
 222         ASSERT(0);
 223     }
 224
 225   /* Destroy libungif structure */
 226   DGifCloseFile(gif);
 227
 228   /* Finish image */
 229   return image_io_read_data_finish(&rdi, io);
 230 }