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

length() float Point2d::length ( ) const 到原点的距离 函数调用图: