// work for wxMemoryDC. So that is why we assume wxDC
// is wxWindowDC (wxClientDC, wxMemoryDC and wxPaintDC
// are derived from it) and use its m_window.
// work for wxMemoryDC. So that is why we assume wxDC
// is wxWindowDC (wxClientDC, wxMemoryDC and wxPaintDC
// are derived from it) and use its m_window.