drawing moving shapes

["Rob Barnes" <robcb85 gmail com>]

I'm trying to write a simple program that draws a moving polygon on the
screen. I started with the scribble-simple example and modified to draw the
moving shape by redrawing the shape in the background color in the previous
position first then drawing it in the foreground color in the current
position. It works fine, except it only refreshes when something happens
such as mouse movement, click, expose, window adjustment. So to keep things
moving I have to keep moving the mouse around, but it stops if the mouse
stops, even though the polygon is being redrawn contently.

Thanks.

-RobB