_getHandleCount _getHandlePoint _getHandleType _hitTestBox _isHandleFixed _load _output _points _save _setHandlePoint _subtype angle center endPoint getPoints getSubType isBeeline isRayline length setBeeline setEndPoint setRayline setStartPoint startPoint

isBeeline() bool MgLine::isBeeline ( ) const 返回是否为无穷直线