def Draw(self, dc):
        dc.BeginDrawing()    # for Windows compatibility
        # Since we are a scrolling window we need to prepare the DC
        self.PrepareDC(dc)

        dc.SetBackground(wx.Brush(self.GetBackgroundColour()))
        dc.Clear()

        for link in self.link_dict.itervalues():
            link.Draw(dc)
        for node in self.node_dict.itervalues():
            node.Draw(dc)
        dc.EndDrawing()