ENH:Added lines to wedges (covered by new test TestMarksWedgeLine). Moved the computation of the number of iterations for drawing an arc in its own protected method, to be used by both DrawEllipseWedge() and DrawEllipticArc(). In vtkContext2D, DrawEllipse delegates its job to DrawArc which delegates the job the device (as the tessellation is only required in OpenGL device, not in another device that could support draw of arcs directly (e.g. SVG) ).