public int getScrollableBlockIncrement( Rectangle visibleRect, int orientation, int direction) {  return 0; }
public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) { Dimension tsize = getTileSize(zoom);  if (orientation == SwingConstants.VERTICAL) { return (visibleRect.height / tsize.height) * tsize.height; } else { return (visibleRect.width / tsize.width) * tsize.width; } }
	public int getScrollableBlockIncrement(		Rectangle visibleRect,		int orientation,		int direction) {		// TODO Auto-generated method stub		return 0;	}