add angle angle2 angledVector angleTo angleTo2 crossProduct distanceToVector dotProduct get isCodirectionalTo isCodirectionalTo isDegenerate isEqualTo isLeftOf isOppositeTo isOppositeTo isParallelTo isParallelTo isPerpendicularTo isPerpendicularTo isRightOf isUnitVector isZeroVector kIdentity kXAxis kYAxis length lengthSquare negate normalize operator!= operator* operator* operator* operator* operator* operator*= operator*= operator+ operator+= operator- operator- operator-= operator/ operator/ operator/= operator== perpVector projectResolveVector projectScaleToVector resolveVector resolveVector scaleBy scaleBy scaledVector set set setAngleLength setLength subtract transform unitVector Vector2d Vector2d Vector2d x y

isParallelTo() [1/2] bool Vector2d::isParallelTo ( const Vector2d &  vec, const Tol &  tol = Tol::gTol()  ) const 判断两个矢量是否平行 判断本矢量和另一个矢量是否平行，零矢量和任何矢量平行 参数 [in] vec 另一个矢量 [in] tol 判断的容差，用到其矢量容差值 返回 是否平行 函数调用图: 这是这个函数的调用关系图: