The PlanarFigureMapper draws the control points in method ::DrawMarker(...) even if the given opacity is 0.
This is totally unnecesary as nothing is visible anyway. It would be faster to just return at the beginning of the method if teh two given opacities (one for the outline, one for the filling) are both 0.
Most likely this will not be noticably at all. However, as our rendering is sometimes a bit slow, every tweak is welcome.