class interface DRAWABLE_ROUND_RECTANGLE
creation
   make
      --  Creation.
feature(s) from DRAWABLE_RECTANGLE
   --  Position
   set_position (rect: RECTANGLE)
      --  Set rectangle to be drawn.
      require
         valid_rectangle: rect /= Void
      ensure
         done: position.is_equal(rect)
feature(s) from DRAWABLE_ROUND_RECTANGLE
   --  Position
   set_corner (width, height: INTEGER)
      --  Set the width and height of the ellipse used to draw the 
      --  rounded corners of the rectangle.
      ensure
         done: round_width = width and then round_height = height
invariant
   valid_position: position /= Void;
end of DRAWABLE_ROUND_RECTANGLE