iOS 引导页挖空透明

1. 使用CAShapeLayer 然后使用UIBezierPath 换线条填充颜色黑色

let maskLayer = CAShapeLayer()
    func configMask(rect:CGRect) {
        let fromPath = maskLayer.path

        maskLayer.fillColor = UIColor.black.cgColor
        var radius:CGFloat = 5
        let frame = rect
        radius = min(radius, min(frame.width / 2.0, frame.height / 2.0))
        let highlightedPath = UIBezierPath(roundedRect: frame, cornerRadius: radius)
        let toPath = UIBezierPath(rect: bgView.bounds)
        toPath.append(highlightedPath)
        maskLayer.path = toPath.cgPath

     ///  CAShapeLayerFillRule.evenOdd 交叉挖空 另外一个是填充
        maskLayer.fillRule = CAShapeLayerFillRule.evenOdd
        bgView.layer.mask = maskLayer
        
        let animation = CABasicAnimation(keyPath: "path")
        animation.duration = 1
        animation.fromValue = fromPath
        animation.toValue = toPath
        maskLayer.add(animation, forKey: nil)
    }

2 使用方法

1. 添加属性

@IBOutlet weak var bgMM: UIButton!
    var bgView:TEEESAVie3w = Bundle.main.loadNibNamed("TEEESAVie3w", owner: nil, options: nil)!.first! as! TEEESAVie3w

override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
//        let rect = CGRect.init(x: 0, y: 100.0, width: 100, height: 100)
//
        bgView.frame = self.view.bounds
        self.view.addSubview(bgView)
        
        let rect =  self.view.convert(self.bgMM.frame, from: self.bgMM.superview)
        self.configMask(rect: rect)
        
        self.view.backgroundColor = UIColor.red
    }

效果如下

Simulator Screen Shot - iPhone 12 mini - 2020-11-19 at 23.27.33.png