dcMem.SelectObject(bitmap);
dc.Blit(0, 0, bitmap.GetWidth(), bitmap.GetHeight(), & dcMem, 0, 0);
dcMem.SelectObject(wxNullBitmap);
dcMem.SelectObject(bitmap);
dc.Blit(0, 0, bitmap.GetWidth(), bitmap.GetHeight(), & dcMem, 0, 0);
dcMem.SelectObject(wxNullBitmap);