CAReplicatorLayer使用

之前埋了个坑，要介绍一下这个CAReplicatorLayer的，结果一直也没写，今天想起来还是简单写一下吧。

直接上代码：
swift
override func viewDidLoad() {
super.viewDidLoad()

    // Do any additional setup after loading the view.
    
    let subView = UIView(frame: CGRect(x: 100, y: 100, width: 100, height: 100))
    subView.backgroundColor = UIColor.lightGray
    view.addSubview(subView)
    
    let animatedLayer = CALayer()
    animatedLayer.frame = CGRect(x: 0, y: 45, width: 10, height: 10)
    animatedLayer.cornerRadius = 5
    
    let animation = CABasicAnimation(keyPath: "transform.scale")
    animation.fromValue = NSNumber(value: 1)
    animation.toValue = NSNumber(value: 0.5)
    animation.duration = 1.9
    animation.autoreverses = false
    animation.repeatCount = Float.greatestFiniteMagnitude
    
    animatedLayer.backgroundColor = UIColor.red.cgColor
    animatedLayer.add(animation, forKey: "scale")
    
    let replicatorLayer = CAReplicatorLayer()
    replicatorLayer.frame = subView.bounds
    replicatorLayer.addSublayer(animatedLayer)
    replicatorLayer.instanceCount = 20
    replicatorLayer.instanceDelay = 0.1
    replicatorLayer.instanceTransform = CATransform3DMakeRotation(CGFloat.pi*2/20, 0, 0, 1)
    
    subView.layer.addSublayer(replicatorLayer)
}

简单说一下，就是只要创建一个** CAReplicatorLayer**，然后在这个layer上添加子layer，就可以根据需要复制出相应的layer（复制的是子layer），如果子layer有动画，它复制出的也会执行动画，这就很有灵性了，看一下每个属性都是做什么的：

```swift```
instanceCount：需要复制的数量
instanceDelay：复制出来的layer执行动画跟上一个执行动画的延迟
instanceTransform：复制出的layer的排列规则

😄

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