swift - 屏幕截屏

    var snapshot: UIImage {
        UIGraphicsBeginImageContext(view.bounds.size)
        view.layer.renderInContext(UIGraphicsGetCurrentContext())
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }

---swift 3.0---
extension UIView {
    var snapshot: UIImage {
        UIGraphicsBeginImageContext(self.bounds.size)
        self.layer.render(in: UIGraphicsGetCurrentContext()!)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image!
    }
}