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

isEqualTo() bool Vector2d::isEqualTo ( const Vector2d &  v, const Tol &  tol = Tol::gTol()  ) const 用欧拉规则判断两个矢量是否相等 如果两个矢量相减的差矢量的长度不大于矢量容差，则相等 参数 v 比较的另一个矢量 tol 判断的容差，用到其矢量容差 返回 如果相等，则返回true，否则返回false 函数调用图: 这是这个函数的调用关系图: