add asVector distanceSquare distanceTo get isDegenerate isEqualTo kInvalid kOrigin length negate offset offset operator!= operator* operator* operator* operator* operator*= operator*= operator+ operator+ operator+ operator+= operator+= operator- operator- operator- operator-= operator/ operator/= operator== Point2d Point2d Point2d polarPoint rulerPoint rulerPoint scaleBy scaleBy set set subtract subtract transform x y

operator+=() [2/2] Point2d& Point2d::operator+= ( const Vector2d &  vec ) 用矢量平移, 点 += 矢量