class interface DRAWABLE_POLYLINE

creation
   make
      --  Create.


feature(s) from DRAWABLE_POLYLINE
   --  Position

   empty: BOOLEAN
      --  Is the polyline empty (no points)?


   reset
      --  Reset the point list representing the polyline.

      ensure
         done: empty

   add_point (pt: POINT)
      --  Add a new point at the end of the polyline.

      require
         valid_point: pt /= Void
      ensure
         ok: not empty

invariant
   valid_position: line /= Void;

end of DRAWABLE_POLYLINE