+ unsigned AddPath(unsigned start_index, unsigned end_index, const Colour & shading=Colour(0.6,0.6,0.6,1), const Colour & stroke=Colour(0,0,0,0));
+ unsigned AddBezier(const Bezier & bezier);
+ unsigned Add(ObjectType type, const Rect & bounds, unsigned data_index = 0, QuadTreeIndex qtnode = 0);