纵向和横向模式下的可缩放全屏图像

Question

我是编程初学者。我有一个应用程序，您可以在其中点击显示的任何图像，以全屏模式显示该图像，并且可以捏缩放。我遇到的问题是，如果您旋转手机，则图像只有一半可见。

我正在使用滚动视图来实现缩放功能，因为这似乎是实现它的最佳方式的共识。

它在纵向模式下完美运行，或者如果我在应用程序已经处于横向方向时进入全屏图像，但如果我在全屏图像时进入横向，那就出错了。代码如下：

class PictureDetailViewController: UIViewController, UIScrollViewDelegate {

@IBOutlet weak var scrollView: UIScrollView!
var routeData = IndividualRoute(numberOfRoute: UserDefaults.standard.integer(forKey: "currentRoute"))

var detailPicture = UserDefaults.standard.bool(forKey: "segueFromDetailvc")

var detailImage = UIImageView()

override func viewDidLoad() {
    super.viewDidLoad()

    routeData.routesValues()
    scrollView.delegate = self
    selectImage()
    scrollView.frame = UIScreen.main.bounds
    scrollView.addSubview(detailImage)
    scrollViewContents()
    setupConstraints()
    let scrollViewFrame = scrollView.frame
    let scaleWidth = scrollViewFrame.size.width / scrollView.contentSize.width
    let scaleHieght = scrollViewFrame.size.height / scrollView.contentSize.height
    let minScale = min(scaleHieght, scaleWidth)
    scrollView.minimumZoomScale = minScale
    scrollView.maximumZoomScale = 1
    scrollView.zoomScale = minScale
    let tap = UITapGestureRecognizer(target: self, action: #selector(dismissFullscreen))
    tap.numberOfTapsRequired = 2
    view.addGestureRecognizer(tap)

}

//****************************************

//Image Setup

func setupConstraints() {

    scrollView.translatesAutoresizingMaskIntoConstraints = false

    NSLayoutConstraint.activate([
        scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
        scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
        scrollView.topAnchor.constraint(equalTo: view.topAnchor),
        scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
        scrollView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
        scrollView.centerYAnchor.constraint(equalTo: view.centerYAnchor)])

    scrollView.contentSize = (detailImage.image?.size)!


}

func selectImage() {
    if !detailPicture {
        let foo = "\(routeData.achievements[UserDefaults.standard.integer(forKey: "currentAchievement")])"
        detailImage.image = UIImage(named: "\(foo.folding(options: .diacriticInsensitive, locale: nil)) 0")
    } else {
        let foo = "\(routeData.achievements[0])"
        detailImage.image = UIImage(named: "\(foo.folding(options: .diacriticInsensitive, locale: nil)) 0")
        print("\(foo.folding(options: .diacriticInsensitive, locale: nil)) 0")
    }

    guard let width = detailImage.image?.size.width else {
        return
    }
    guard let height = detailImage.image?.size.height else {
        return
    }

    let frame: CGRect = CGRect(x: 0, y: 0, width: width, height: height)
    detailImage.frame = frame
    detailImage.isUserInteractionEnabled = true

}

//**************************************

//Scrollview setup


@objc func dismissFullscreen(){
    scrollView.setZoomScale(1, animated: true)
}

func scrollViewContents() {

    let boundSize = UIScreen.main.bounds.size
    var contentFrame = detailImage.frame

    if contentFrame.size.width < boundSize.width {
        contentFrame.origin.x = (boundSize.width - contentFrame.size.width) / 2
    } else {
        contentFrame.origin.x = 0
    }
    if contentFrame.size.height < boundSize.height {
        contentFrame.origin.y = (boundSize.height - contentFrame.size.height) / 2
    } else {
        contentFrame.origin.y = 0
    }

    detailImage.frame = contentFrame

}

func scrollViewDidZoom(_ scrollView: UIScrollView) {
    scrollViewContents()
}

func viewForZooming(in scrollView: UIScrollView) -> UIView? {

    return detailImage
}

很抱歉发布了这么多代码，但它几乎都是相关的（我认为）。

这里是问题的截图：

Answer 1

好的，我已经解决了！高兴得跳了起来。

我设置了一个名为 setupScale() 的新函数，该函数在视图显示时在 viewdidload 中调用。我还添加了 viewwillLayoutSubview() 覆盖并在其中调用了 setupScale() 函数。

如果看起来像这样：

private func setupScale() {

    scrollView.frame = UIScreen.main.bounds
    scrollView.contentSize = (detailImage.image?.size)!
    scrollViewContents()
    let scrollViewFrame = scrollView.frame
    let scaleWidth = scrollViewFrame.size.width / scrollView.contentSize.width
    let scaleHieght = scrollViewFrame.size.height / scrollView.contentSize.height
    let minScale = min(scaleHieght, scaleWidth)
    scrollView.minimumZoomScale = minScale
    scrollView.maximumZoomScale = 1
    scrollView.zoomScale = minScale
}
override func viewWillLayoutSubviews() {
    setupScale()
}

在我的 iPad 和 iPhone 7 上，横向和纵向的结果看起来都很完美。