调整UIView大小以适合CGPath

   override func viewDidLoad() {

       super.viewDidLoad()

       let path = CGMutablePath()

       // 创建一个CGFloat类型的坐标

       path.move(to: CGPoint(x: 100, y: 100))

       // 连接点

       path.addLine(to: CGPoint(x: 200, y: 200))

       // 添加曲线

       path.addCurve(to: CGPoint(x: 300, y: 100), control1: CGPoint(x: 250, y: 150), control2: CGPoint(x: 200, y: 100))

       // 关闭路径

       path.closeSubpath()

       let view = UIView(frame: CGRect(x: 0, y: 0, width: 400, height: 400))

       view.backgroundColor = .red

       view.layer.cornerRadius = 20

       view.layer.mask = CAShapeLayer(path: path)

       view.layer.mask.fillRule = .evenOdd

       view.layer.mask.backgroundColor = UIColor.clear.cgcolor

       view.layer.mask.borderColor = UIColor.blue.cgColor

       view.layer.mask.borderWidth = 1

       view.layer.cornerRadius = 20

       view.layer.shouldRasterize = true

       view.layer.rasterizationScale = UIScreen.main.scale

       view.layer.contentsGravity = .resizeAspectFill

       view.layer.contentsScale = UIScreen.main.scale

       view.layer.renderInContext(UIGraphicsGetCurrentContext())

       view.layer.contents = UIColor.black.cgImage

       view.frame = CGRect(x: 100, y: 100, width: 200, height: 200)

       view.layer.render(in: UIGraphicsGetCurrentContext()!)

       view.layer.contents = UIColor.clear.cgImage

   }