To emulate the Matlab behaviour, drawnow not only flushes the postponed graphics commands of the current window, but also reveals the double buffer pixmap if the DoubleBuffer property is 'on'.
Example
f=figure('DoubleBuffer','on');
t=linspace(0,2*%pi,128);
h=plot(t,sin(t));
axis(axis());
for i=[1:100 99:-1:1]
// set(h,'CData',sin(i*t/50));
h.YData=sin(i*t/50);
drawnow
end