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