expose event behaviour

[REYMOND Dominique <reymond d labogeo pf>]

Hi all!

Could somebody tell me why, after an expose event signal,
the concerned window, or area is redrawn systematically several times
(at least 2 times, often 3 of 4 times, specially in a fullscreen
window).This strange.

I have cautiously  add the following code at the beginning,
in the redraw function (called by the expose event):
../..
if (evt->count > 0) return;  
.../..

but it just avoid 1 or 2 executions of the redraw function.

In fact when we plot or draw a few number of points, we don't see
the problem : the drawing function is instantaneous;
but this becomes a real problem and a big waste of time, for
redrawing vectors and matrix containing several millions of points:
it takes at least 40 seconds per call.
I don't know what to do to avoid this problem.  

I did not observed such a problem with my programs under Windows,
so I am asking that maybe this is default of the event handler
between gtk and the X_windows ??? (this is just a question )

Does anybody already observed this problem ?

Thanks a lot for your help

Dominique Reymond