iOS图片实现指定区域拉伸

//背景图
lazy var bgImg: UIImageView = {
let img = UIImageView()
img.image = UIImage(named: "search_hot_bg")?.resizableImage(withCapInsets: UIEdgeInsets(top: 28, left: 38, bottom: 43, right: 38), resizingMode: .stretch)
return img
}()