var rotation: CGFloat = 0
    var scale: CGFloat = 1

    override func viewDidLoad() {
        super.viewDidLoad()
        
        //1. 視圖默認(rèn)可以接收觸摸事件
        let firstView = FirstView(frame: CGRect(x: 100, y: 100, width: 300, height: 300))
        //當(dāng)父視圖不能交互時，所有子視圖都不能交互
        //UIImageView: 默認(rèn)為false，不能交互
//        firstView.userInteractionEnabled = false
        firstView.backgroundColor = UIColor.redColor()
        self.view.addSubview(firstView)
        
        //2. 視圖結(jié)構(gòu)不能改變事件傳遞順序
        let secondView = SecondView(frame: CGRect(x: 0, y: 0, width: 150, height: 150))
        //用戶是否可以交互
        //UIView默認(rèn)為true
//        secondView.userInteractionEnabled = false
        secondView.backgroundColor = UIColor.greenColor()
//        self.view.addSubview(secondView)
        firstView.addSubview(secondView)
        
        let rotate = UIRotationGestureRecognizer(target: self, action: #selector(didRotate(_:)))
        firstView.addGestureRecognizer(rotate)
        
        let pinch = UIPinchGestureRecognizer(target: self, action: #selector(didPinch(_:)))
        firstView.addGestureRecognizer(pinch)
    }
    //旋轉(zhuǎn)
    func didRotate(sender: UIRotationGestureRecognizer) {
        let firstView = sender.view!
//        firstView?.transform = CGAffineTransformMakeRotation(sender.rotation)
        
        firstView.transform = CGAffineTransformRotate(firstView.transform, sender.rotation - rotation)
        rotation = sender.rotation
        
        print(sender.rotation)
        
        if sender.state == .Ended {
            rotation = 0
        }
        
        //手勢每次都是從0開始
        print("rotate: ", sender.rotation)
    }
    //放大、縮小
    func didPinch(sender: UIPinchGestureRecognizer) {
        let firstView = sender.view!
        
        //??????
        firstView.transform = CGAffineTransformScale(firstView.transform, sender.scale - scale + 1 , sender.scale - scale + 1)
        
        scale = sender.scale
        
        if sender.state == .Ended {
            scale = 1
        }
        
        print("scale: ", sender.scale)
    }