小编Jis*_*j T的帖子

问题图像截图

class ViewController: UIViewController {
    var shadow : UIView!
    override func viewDidLoad() {
        super.viewDidLoad()
        shadow = UIView(frame: CGRect(x: 50,y: 50,width: 150,height:150))
        shadow.backgroundColor = .red
        shadow.dropShadow()
        self.view.addSubview(shadow)

    }

    @IBAction func btnActn(_ sender: Any) {self.shadow.frame = CGRect(x: 50,y: 50,width: 150,height: 50)

    }

}

extension UIView {
 func dropShadow(scale: Bool = true) {
        layer.masksToBounds = false
        layer.shadowColor = UIColor.black.cgColor
        layer.shadowOpacity = 0.5
        layer.shadowOffset = CGSize(width: 1, height: 1)
        layer.shadowRadius = 2
        layer.shadowPath = UIBezierPath(rect: bounds).cgPath
        layer.shouldRasterize = true
        layer.rasterizationScale = scale ? UIScreen.main.scale …