+ /// Start 2D point of the arc
+ inline static const std::string& START_ID()
+ {
+ static const std::string ID = "start_point";
+ return ID;
+ }
+
+ /// End 2D point of the arc
+ inline static const std::string& END_ID()
+ {
+ static const std::string ID = "end_point";
+ return ID;
+ }
+
+ /// Arc radius.
+ static const std::string& RADIUS_ID()
+ {
+ static const std::string ID("radius");
+ return ID;
+ }
+
+ /// Arc angle.
+ static const std::string& ANGLE_ID()
+ {
+ static const std::string ID("angle");
+ return ID;
+ }