CAGradientLayer发布使用CAShapeLayer创建的动画圆圈

I am drawing an animated circle using the UIBezierPath and CAShapeLayer. Now while adding the gradient effect the problem occurring is - CAGradientLayer adds it's gradient effect from upside down. But I want gradient effect from the starting point of the circle to the end point of the circle.I am drawing an animated circle using the UIBez