所以，我有一个使用CABasicAnimation旋转和缩放的CALayer。由于图层正在旋转，因此帧会返回包含最高到最低x和y值的帧（因此这将大于实际显示的图层）。并且，虽然如果不进行缩放，边界将起作用，但是图层的边界不会。这是我的自定义UIView子类的代码：
func rotateCircleView(duration: CFTimeInterval = 1.0) {
let rotateAnimation = CABasicAnimation(keyPath: "transform.rotation")
rotateAnimation.fromValue = 0.0
rotateAnimation.toValue = CGFloat(M_PI * 2.0)
rotateAnimation.duration = duration
rotateAnimation.repeatCount = Float.infinity
self.layer.addAnimation(rotateAnimation, forKey: rotateKey)
}
func shrinkCircleView(duration: CFTimeInterval = 1.0, to: Double) {
let from = self.getCurrentAnimationScale()
let shrinkAnimation = CABasicAnimation(keyPath: "transform.scale")
shrinkAnimation.additive = true
shrinkAnimation.fromValue = from - to
shrinkAnimation.toValue = 0
shrinkAnimation.duration = duration
shrinkAnimation.removedOnCompletion = true
let scaleTransform = CATransform3DMakeScale(CGFloat(to), CGFloat(to), 1.0)
layer.transform = scaleTransform
layer.addAnimation(shrinkAnimation, forKey: "shrinkAnimation")
}
func getCurrentAnimationScale() -> Double{
if let temp = self.layer.presentationLayer(){
// return scale of presentationLayer
} else{
// return scale of self.layer
}
}