How to rubberband

[John Kodis <kodis jagunet com>]

I've written a tiny applet called "Where Am I?" that does a cursor
grab and shows the width and height of the area across which the
cursor is dragged.  I'd like to draw a set of rubberband line to mark
off the extent of this region, but don't know what technique I should
use to do this.  If I can do marching ants, that would be even
better.  Any suggestions would be appreciated.

-- John Kodis.