+ // obtain the surface used for painting:
+ wxPoint origin;
+ wxIDirectFBSurfacePtr surface;
+
+ wxRect rectOrig(rect ? *rect : wxRect(win->GetSize()));
+ wxRect r;
+
+ if ( !win->IsShownOnScreen() )
+ {
+ // leave 'r' rectangle empty to indicate the window is not visible,
+ // see below (below "create the surface:") for how is this case handled
+ }
+ else
+ {
+ // compute painting rectangle after clipping if we're in PaintWindow
+ // code, otherwise paint on the entire window:
+ r = rectOrig;
+
+ const wxRegion& updateRegion = win->GetUpdateRegion();
+ if ( win->GetTLW()->IsPainting() && !updateRegion.IsEmpty() )
+ {
+ r.Intersect(updateRegion.AsRect());
+ wxCHECK_RET( !r.IsEmpty(), _T("invalid painting rectangle") );
+
+ // parent TLW will flip the entire surface when painting is done
+ m_shouldFlip = false;
+ }
+ else
+ {
+ // One of two things happened:
+ // (1) the TLW is not being painted by PaintWindow() now; or
+ // (2) we're drawing on some window other than the one that is
+ // currently painted on by PaintWindow()
+ // In either case, we need to flip the surface when we're done
+ // painting and we don't have to use updateRegion for clipping.
+ // OTOH, if the window is (partially) hidden by being
+ // out of its parent's area, we must clip the surface accordingly.
+ r.Intersect(GetUncoveredWindowArea(win));
+ m_shouldFlip = true; // paint the results immediately
+ }
+ }
+
+ // 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
+ // rect.GetPosition() has coordinates (0,0) in the DC:
+ origin.x = rectOrig.x - r.x;
+ origin.y = rectOrig.y - r.y;
+
+ // m_shouldFlip was set in the "if" block above this one
+ }
+
+ if ( !surface )
+ return;