img_xcf.c

sdl的image开发包

  h = (xcf_hierarchy *) malloc (sizeof (xcf_hierarchy));
  h->width  = SDL_ReadBE32 (src);
  h->height = SDL_ReadBE32 (src);
  h->bpp    = SDL_ReadBE32 (src);

  h->level_file_offsets = NULL;
  i = 0;
  do {
    h->level_file_offsets = (Uint32 *) realloc (h->level_file_offsets, sizeof (Uint32) * (i+1));
    h->level_file_offsets [i] = SDL_ReadBE32 (src);
  } while (h->level_file_offsets [i++]);

  return h;
}

void free_xcf_level (xcf_level * l) {
  free (l->tile_file_offsets);
  free (l);
}

xcf_level * read_xcf_level (SDL_RWops * src) {
  xcf_level * l;
  int i;

  l = (xcf_level *) malloc (sizeof (xcf_level));
  l->width  = SDL_ReadBE32 (src);
  l->height = SDL_ReadBE32 (src);

  l->tile_file_offsets = NULL;
  i = 0;
  do {
    l->tile_file_offsets = (Uint32 *) realloc (l->tile_file_offsets, sizeof (Uint32) * (i+1));
    l->tile_file_offsets [i] = SDL_ReadBE32 (src);
  } while (l->tile_file_offsets [i++]);

  return l;
}

void free_xcf_tile (unsigned char * t) {
  free (t);
}

unsigned char * load_xcf_tile_none (SDL_RWops * src, Uint32 len, int bpp, int x, int y) {
  unsigned char * load;

  load = (char *) malloc (len); // expect this is okay
  SDL_RWread (src, load, len, 1);

  return load;
}

unsigned char * load_xcf_tile_rle (SDL_RWops * src, Uint32 len, int bpp, int x, int y) {
  unsigned char * load, * t, * data, * d;
  Uint32 reallen;
  int i, size, count, j, length;
  unsigned char val;

  t = load = (char *) malloc (len);
  reallen = SDL_RWread (src, t, 1, len);

  data = (char *) malloc (x*y*bpp);
  for (i = 0; i < bpp; i++) {
    d    = data + i;
    size = x*y;
    count = 0;
 
    while (size > 0) {
      val = *t++;

      length = val;
      if (length >= 128) {
	length = 255 - (length - 1);
	if (length == 128) {
	  length = (*t << 8) + t[1];
	  t += 2;
	}

	count += length;
	size -= length;

	while (length-- > 0) {
	  *d = *t++;
	  d += bpp;
	}
      }
      else {
	length += 1;
	if (length == 128) {
	  length = (*t << 8) + t[1];
	  t += 2;
	}

	count += length;
	size -= length;

	val = *t++;

	for (j = 0; j < length; j++) {
	  *d = val;
	  d += bpp;
	}
      }
    }
  }

  free (load);
  return (data);
}

static Uint32 rgb2grey (Uint32 a) {
  Uint8 l;
  l = 0.2990 * ((a && 0x00FF0000) >> 16)
    + 0.5870 * ((a && 0x0000FF00) >>  8)
    + 0.1140 * ((a && 0x000000FF));

  return (l << 16) | (l << 8) | l;
}

void create_channel_surface (SDL_Surface * surf, xcf_image_type itype, Uint32 color, Uint32 opacity) {
  Uint32 c = 0;

  switch (itype) {
  case IMAGE_RGB:
  case IMAGE_INDEXED:
    c = opacity | color;
    break;
  case IMAGE_GREYSCALE:
    c = opacity | rgb2grey (color);
    break;
  }
  SDL_FillRect (surf, NULL, c);
}

int do_layer_surface (SDL_Surface * surface, SDL_RWops * src, xcf_header * head, xcf_layer * layer, load_tile_type load_tile) {
  xcf_hierarchy * hierarchy;
  xcf_level     * level;
  unsigned char * tile;
  Uint8  * p8;
  Uint16 * p16;
  Uint32 * p;
  int x, y, tx, ty, ox, oy, i, j;
  Uint32 *row;

  SDL_RWseek (src, layer->hierarchy_file_offset, SEEK_SET);
  hierarchy = read_xcf_hierarchy (src);

  level = NULL;
  for (i = 0; hierarchy->level_file_offsets [i]; i++) {
    SDL_RWseek (src, hierarchy->level_file_offsets [i], SEEK_SET);
    level = read_xcf_level (src);

    ty = tx = 0;
    for (j = 0; level->tile_file_offsets [j]; j++) {
      SDL_RWseek (src, level->tile_file_offsets [j], SEEK_SET);
      ox = tx+64 > level->width ? level->width % 64 : 64;
      oy = ty+64 > level->height ? level->height % 64 : 64;

      if (level->tile_file_offsets [j+1]) {
	tile = load_tile
	  (src,
	   level->tile_file_offsets [j+1] - level->tile_file_offsets [j],
	   hierarchy->bpp,
	   ox, oy);
      }
      else {
	tile = load_tile
	  (src,
	   ox*oy*6,
	   hierarchy->bpp,
	   ox, oy);
      }

      p8  = tile;
      p16 = (Uint16 *) p8;
      p   = (Uint32 *) p8;
      for (y=ty; y < ty+oy; y++) {
	row = (Uint32 *)((Uint8 *)surface->pixels + y*surface->pitch + tx*4);
	switch (hierarchy->bpp) {
	case 4:
	  for (x=tx; x < tx+ox; x++)
	    *row++ = Swap32 (*p++);
	  break;
	case 3:
	  for (x=tx; x < tx+ox; x++) {
	    *row = 0xFF000000;
	    *row |= ((Uint32) *(p8++) << 16);
	    *row |= ((Uint32) *(p8++) << 8);
	    *row |= ((Uint32) *(p8++) << 0);
	    row++;
	  }
	  break;
	case 2: // Indexed/Greyscale + Alpha
	  switch (head->image_type) {
	  case IMAGE_INDEXED:
	    for (x=tx; x < tx+ox; x++) {
	      *row =  ((Uint32) (head->cm_map [*p8*3])     << 16);
	      *row |= ((Uint32) (head->cm_map [*p8*3+1])   << 8);
	      *row |= ((Uint32) (head->cm_map [*p8++*3+2]) << 0);
	      *row |= ((Uint32) *p8++ << 24);;
	      row++;
	    }
	    break;
	  case IMAGE_GREYSCALE:
	    for (x=tx; x < tx+ox; x++) {
	      *row = ((Uint32) *p8 << 16);
	      *row |= ((Uint32) *p8 << 8);
	      *row |= ((Uint32) *p8++ << 0);
	      *row |= ((Uint32) *p8++ << 24);;
	      row++;
	    }
	    break;	    
	  default:
	    fprintf (stderr, "Unknown Gimp image type (%d)\n", head->image_type);
	    return 1;
	  }
	  break;
	case 1: // Indexed/Greyscale
	  switch (head->image_type) {
	  case IMAGE_INDEXED:
	    for (x = tx; x < tx+ox; x++) {
	      *row++ = 0xFF000000
		| ((Uint32) (head->cm_map [*p8*3]) << 16)
		| ((Uint32) (head->cm_map [*p8*3+1]) << 8)
		| ((Uint32) (head->cm_map [*p8*3+2]) << 0);
	      p8++;
	    }
	    break;
	  case IMAGE_GREYSCALE:
	    for (x=tx; x < tx+ox; x++) {
	      *row++ = 0xFF000000
		| (((Uint32) (*p8)) << 16)
		| (((Uint32) (*p8)) << 8)
		| (((Uint32) (*p8++)) << 0);
	    }
	    break;	    
	  default:
	    fprintf (stderr, "Unknown Gimp image type (%d)\n", head->image_type);
	    return 1;
	  }
	  break;
	}
      }
      tx += 64;
      if (tx >= level->width) {
	tx = 0;
	ty += 64;
      }
      if (ty >= level->height) {
	break;
      }

      free_xcf_tile (tile);
    }
    free_xcf_level (level);
  }

  free_xcf_hierarchy (hierarchy);
  
  return 0;
}

SDL_Surface *IMG_LoadXCF_RW(SDL_RWops *src) {
  SDL_Surface *surface, *lays;
  xcf_header * head;
  xcf_layer  * layer;
  xcf_channel ** channel;
  int read_error, chnls, i, offsets;
  Uint32 offset, fp;

  unsigned char * (* load_tile) (SDL_RWops *, Uint32, int, int, int);

  /* Check to make sure we have something to do */
  if ( ! src ) {
    return NULL;
  }

  /* Initialize the data we will clean up when we're done */
  surface = NULL;
  read_error = 0;

  head = read_xcf_header (src);

  switch (head->compr) {
  case COMPR_NONE:
    load_tile = load_xcf_tile_none;
    break;
  case COMPR_RLE:
    load_tile = load_xcf_tile_rle;
    break;
  default:
    fprintf (stderr, "Unsupported Compression.\n");
    free_xcf_header (head);
    return NULL;
  }

  /* Create the surface of the appropriate type */
  surface = SDL_AllocSurface(SDL_SWSURFACE, head->width, head->height, 32,
			     0x00FF0000,0x0000FF00,0x000000FF,0xFF000000);

  if ( surface == NULL ) {
    IMG_SetError("Out of memory");
    goto done;
  }

  head->layer_file_offsets = NULL;
  offsets = 0;

  while ((offset = SDL_ReadBE32 (src))) {
    head->layer_file_offsets = (Uint32 *) realloc (head->layer_file_offsets, sizeof (Uint32) * (offsets+1));
    head->layer_file_offsets [offsets] = offset;
    offsets++;
  }
  fp = SDL_RWtell (src);
 
  lays = SDL_AllocSurface(SDL_SWSURFACE, head->width, head->height, 32,
			  0x00FF0000,0x0000FF00,0x000000FF,0xFF000000);

  if ( lays == NULL ) {
    IMG_SetError("Out of memory");
    goto done;
  }

  // Blit layers backwards, because Gimp saves them highest first
  for (i = offsets; i > 0; i--) {
    SDL_Rect rs, rd;
    SDL_RWseek (src, head->layer_file_offsets [i-1], SEEK_SET);

    layer = read_xcf_layer (src);
    do_layer_surface (lays, src, head, layer, load_tile);
    rs.x = 0;
    rs.y = 0;
    rs.w = layer->width;
    rs.h = layer->height;
    rd.x = layer->offset_x;
    rd.y = layer->offset_y;
    rd.w = layer->width;
    rd.h = layer->height;

    if (layer->visible)
      SDL_BlitSurface (lays, &rs, surface, &rd);
    free_xcf_layer (layer);
  }

  SDL_FreeSurface (lays);

  SDL_RWseek (src, fp, SEEK_SET);

  // read channels
  channel = NULL;
  chnls   = 0;
  while ((offset = SDL_ReadBE32 (src))) {
    channel = (xcf_channel **) realloc (channel, sizeof (xcf_channel *) * (chnls+1));
    fp = SDL_RWtell (src);
    SDL_RWseek (src, offset, SEEK_SET);
    channel [chnls++] = (read_xcf_channel (src));
    SDL_RWseek (src, fp, SEEK_SET);    
  }

  if (chnls) {
    SDL_Surface * chs;

    chs = SDL_AllocSurface(SDL_SWSURFACE, head->width, head->height, 32,
			   0x00FF0000,0x0000FF00,0x000000FF,0xFF000000);

    if (chs == NULL) {
      IMG_SetError("Out of memory");
      goto done;
    }
    for (i = 0; i < chnls; i++) {
      //      printf ("CNLBLT %i\n", i);
      if (!channel [i]->selection && channel [i]->visible) {
	create_channel_surface (chs, head->image_type, channel [i]->color, channel [i]->opacity);
	SDL_BlitSurface (chs, NULL, surface, NULL);
      }
      free_xcf_channel (channel [i]);
    }

    SDL_FreeSurface (chs);
  }

 done:
  free_xcf_header (head);
  if ( read_error ) {
    SDL_FreeSurface(surface);
    IMG_SetError("Error reading XCF data");
    surface = NULL;
  }

  return(surface);
}

#else

/* See if an image is contained in a data source */
int IMG_isXCF(SDL_RWops *src)
{
  return(0);
}

/* Load a XCF type image from an SDL datasource */
SDL_Surface *IMG_LoadXCF_RW(SDL_RWops *src)
{
  return(NULL);
}

#endif /* LOAD_XCF */