Copyright (c) Xoetrope Ltd., 2001-2006, This software is licensed under
the GNU Public License (GPL), please see license.txt for more details. If
you make commercial use of this software you must purchase a commercial
license from Xoetrope.
Enable usage of tiling, i.e drawing of the off-screen sections of the image while dragging.
Parameters: b - boolean specifying whether tiling is to be used or not