+ RgnHandle updatergn = (RgnHandle) updatergnr ;
+ // updatergn is always already clipped to our boundaries
+ // it is in window coordinates, not in client coordinates
+
+ WindowRef window = (WindowRef) MacGetRootWindow() ;
+
+ {
+ // ownUpdateRgn is the area that this window has to repaint, it is in window coordinates
+ RgnHandle ownUpdateRgn = NewRgn() ;
+ CopyRgn( updatergn , ownUpdateRgn ) ;
+
+ SectRgn( ownUpdateRgn , (RgnHandle) MacGetVisibleRegion().GetWXHRGN() , ownUpdateRgn ) ;
+
+ // newupdate is the update region in client coordinates
+ RgnHandle newupdate = NewRgn() ;
+ wxSize point = GetClientSize() ;
+ wxPoint origin = GetClientAreaOrigin() ;
+ SetRectRgn( newupdate , origin.x , origin.y , origin.x + point.x , origin.y+point.y ) ;
+ SectRgn( newupdate , ownUpdateRgn , newupdate ) ;
+ OffsetRgn( newupdate , -origin.x , -origin.y ) ;
+ m_updateRegion = newupdate ;
+ DisposeRgn( newupdate ) ; // it's been cloned to m_updateRegion
+
+ if ( erase && !EmptyRgn(ownUpdateRgn) )
+ {
+ wxWindowDC dc(this);
+ if (!EmptyRgn(ownUpdateRgn))
+ dc.SetClippingRegion(wxRegion(ownUpdateRgn));
+ wxEraseEvent eevent( GetId(), &dc );
+ eevent.SetEventObject( this );
+ GetEventHandler()->ProcessEvent( eevent );
+
+ wxNcPaintEvent eventNc( GetId() );
+ eventNc.SetEventObject( this );
+ GetEventHandler()->ProcessEvent( eventNc );
+ }
+ DisposeRgn( ownUpdateRgn ) ;
+ if ( !m_updateRegion.Empty() )
+ {
+ wxPaintEvent event;
+ event.m_timeStamp = time ;
+ event.SetEventObject(this);
+ GetEventHandler()->ProcessEvent(event);
+ }
+ }
+
+ // now intersect for each of the children their rect with the updateRgn and call MacRedraw recursively
+
+ RgnHandle childupdate = NewRgn() ;
+ for (wxWindowListNode *node = GetChildren().GetFirst(); node; node = node->GetNext())
+ {
+ // calculate the update region for the child windows by intersecting the window rectangle with our own
+ // passed in update region and then offset it to be client-wise window coordinates again
+ wxWindowMac *child = node->GetData();
+ SetRectRgn( childupdate , child->m_x , child->m_y , child->m_x + child->m_width , child->m_y + child->m_height ) ;
+ SectRgn( childupdate , updatergn , childupdate ) ;
+ OffsetRgn( childupdate , -child->m_x , -child->m_y ) ;
+ if ( child->MacGetRootWindow() == window && child->IsShown() && !EmptyRgn( childupdate ) )
+ {
+ // because dialogs may also be children
+ child->MacRedraw( childupdate , time , erase ) ;
+ }
+ }
+ DisposeRgn( childupdate ) ;
+ // eventually a draw grow box here
+