override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        
        imageView.image = UIImage(named: "1.jpg")
        
        imageView.image = UIApplication.shared.delegate?.window??.yj_capture()
    }

}

extension UIView {
    /// 屏幕截图
    func yj_capture() -> UIImage? {
        UIGraphicsBeginImageContextWithOptions(self.bounds.size, self.isOpaque, UIScreen.main.scale)
        if self.responds(to: #selector(drawHierarchy(in:afterScreenUpdates:))) {
            self.drawHierarchy(in: self.bounds, afterScreenUpdates: true)
        } else {
            self.layer.render(in: UIGraphicsGetCurrentContext()!)
        }
        
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
}