旋转视图的问题

Question

我想为UIImageView设置动画。图像只能顺时针旋转。当图像旋转时，我想加快速度。当我加快速度时，它会逆时针旋转，起始位置也不正确。这是我的代码：

func rotateAnimation(theView: UIView, duration: CFTimeInterval = 2.0, repeatCount: Float = 1, toValue: CGFloat = CGFloat(.pi * 2.0), linear: Bool = false, animation: String = "transform.rotation") {
    let rotateAnimation = CABasicAnimation(keyPath: animation)
    let currentLayer = (theView.layer.presentation())
    var currentAngle = CFloat((currentLayer?.value(forKeyPath: "transform.rotation") as? NSNumber)!)
    currentAngle = roundf(currentAngle * 180 / Float(Double.pi))
    print(currentAngle)
    rotateAnimation.fromValue = currentAngle
    if !linear{
    rotateAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseIn)
    }
    rotateAnimation.toValue = toValue
    rotateAnimation.duration = duration
    rotateAnimation.repeatCount = repeatCount
    theView.layer.add(rotateAnimation, forKey: nil)
}

打印显示我纠正角度。

我在下面两次调用此方法。我第二次打电话给它，图像正在旋转：

    rotateAnimation(theView: star, duration: 15.0, repeatCount: Float.infinity, toValue: CGFloat(Double.pi * 2), linear: true)
    delay(delay: 3.5, closure: {
      self.rotateAnimation(theView: self.star, duration: 7, repeatCount: Float.infinity, toValue: CGFloat(Double.pi * 2), linear: true)
    })