CalcBoundBox Contains copy FromPos getEndPoint getLength getMidPoint getStartPoint Intersect Intersect IntersectAndContain isClosed LineSegment2D LineSegment2D LineSegment2D mEndPoint mStartPoint operator= operator== setEndPoint setStartPoint

setStartPoint() void setStartPoint ( const Base::Vector2d &  pt ) 设置起点 设置二维直线段的起点 参数 [in] pt 起点