code: private static boolean isExtracted(SpriteTiled level, int x, int y, Collection<ImageBuffer> tiles)
      {
          final int tw = level.getTileWidth();
          final int th = level.getTileHeight();
          final ImageBuffer surface = level.getSurface();
  
          for (final ImageBuffer tile : tiles)
          {
              if (compareTile(tw, th, surface, x, y, tile, 0, 0))
              {
                  return true;
              }
          }
          return false;
      }
docs: Check if tile has already been extracted regarding the current tile on level rip.
  
  @param level The level rip reference.
  @param x The current level rip horizontal location.
  @param y The current level rip vertical location.
  @param tiles The current extracted tiles.
  @return <code>true</code> if already extracted, <code>false</code> else.