cairo & pixmap

["control H" <control h gmail com>]

Hi,

I'm planning to make my app use cairo instead of GDK based functions.
I'm using a drawing area, which draws into a pixmap when the
"configure" event is emitted, and copies the relevant part of the
pixmap back on the screen on the "expose" event.

When I'm doing the same with cairo, a black screen is the result. The
ref. manual says in the FAQ that I should either turn off double
buffering, or draw in the expose signal. This is also what the example
testcairo (coming along with Gtk) does.

I'm confused. Does this mean that drawing using cairo is slower since
it has to redraw the whole thing again on each expose signal? Or is
there some smart thing in Gtk that somehow knows that when the expose
event is a result of a configure event, it doesn't really do the
drawing but copies the invalidated part back?

Thanks...