UIScrollView缩放uiview到纵横比填充

class ViewController: UIViewController, UIScrollViewDelegate {
    var scrollView: UIScrollView!
    var contentView: UIView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建UIScrollView
        scrollView = UIScrollView(frame: view.bounds)
        scrollView.delegate = self
        scrollView.contentSize = CGSize(width: 1000, height: 1000) // 设置内容大小
        view.addSubview(scrollView)
        
        // 创建UIView作为内容视图
        contentView = UIView(frame: CGRect(x: 0, y: 0, width: 1000, height: 1000))
        contentView.backgroundColor = UIColor.red
        scrollView.addSubview(contentView)
        
        // 设置缩放范围
        scrollView.minimumZoomScale = 0.5
        scrollView.maximumZoomScale = 2.0
        
        // 添加手势识别器
        let doubleTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleDoubleTap(_:)))
        doubleTapGesture.numberOfTapsRequired = 2
        contentView.addGestureRecognizer(doubleTapGesture)
    }
    
    // 双击手势处理
    @objc func handleDoubleTap(_ gesture: UITapGestureRecognizer) {
        if scrollView.zoomScale == 1 {
            // 放大
            scrollView.setZoomScale(2, animated: true)
        } else {
            // 缩小
            scrollView.setZoomScale(1, animated: true)
        }
    }
    
    // UIScrollViewDelegate代理方法，返回需要缩放的视图
    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return contentView
    }
}