Re: draw signals

[Carlos Pereira <carlos pehoe civil ist utl pt>]

> why have a handler redraw the pixmap if nothing has changed 
> and a simple screen update will do?

In your "expose_event" callback you have full control
over everything. You can copy a pixmap to the drawing area
or redraw it first, if you think that is necessary. That's
your choice!

you can have something as this, in the "expose_event" call back:

if (some_condition) pixmap = redraw_pixmap;
else pixmap = get_old_pixmap;

copy_pixmap_to_drawing_area (pixmap);

If some_condition is too difficult to be handled 
automatically (and often is), then just forget 
and redraw always.

Carlos