nanogui@linuxhacker.org

: > characters for speed.  So, on a refresh, the current background
: > color is fillrect'ed to the display, then the non-space characters
: 
: That makes it flicker. You dont do that. 

Whoops

You just skip updating chars that where
: space and are a space now

Only one problem...  If the area really is in need of
refresh, someone's got to draw the background sometime.
Also this requires two copies of contents: before and after screen data.

So now I remember how to do it...  You add the
non-update area (area not included in the expose event)
to the current clipping region, _then_ fillrect to the background
color and don't draw space characters... No flicker, and 
only the screen parts that needed updating ever get painted

Greg