- // if the DC was clipped thanks to rectPaint, we must adjust the origin
- // accordingly; but we do *not* adjust for 'rect', because
+ // create the surface:
+ if ( r.IsEmpty() )
+ {
+ // we're painting on invisible window: the changes won't have any
+ // effect, as the window will be repainted anyhow when it is shown,
+ // but we still need a valid DC so that e.g. text extents can be
+ // measured, so let's create a dummy surface that has the same
+ // format as the real one would have and let the code paint on it:
+ surface = CreateDummySurface(win, rect);
+
+ // painting on hidden window has no effect on TLW's surface, don't
+ // waste time flipping the dummy surface:
+ m_shouldFlip = false;
+ }
+ else
+ {
+ DFBRectangle dfbrect = { r.x, r.y, r.width, r.height };
+ surface = win->GetDfbSurface()->GetSubSurface(&dfbrect);
+
+ // if the DC was clipped thanks to rectPaint, we must adjust the
+ // origin accordingly; but we do *not* adjust for 'rect', because