ios - UIScrollView 中的 UIImageView 缩放和捏合

Question

我尝试了许多不同的方法来实现扩展图像和捏合缩放。我找到了有关如何使用项目中保存的图像执行此操作的教程，但是我正在从 Firebase 检索图像。我希望一张图片占据 ProfileViewController 屏幕的大约一半，而其他图片能够展开整页并且能够缩放。我的代码现在可以做到这一点，但是缩放和位置不干净或易于使用。

var newImageView: UIImageView!



@IBAction func imageTapped(_ sender: UITapGestureRecognizer)  {
    let imageView = sender.view as! UIImageView

    let scrollView = UIScrollView(frame: self.view.frame)


    newImageView = UIImageView(image: imageView.image)
    newImageView.frame = self.view.frame
    newImageView.backgroundColor = .black
    newImageView.contentMode = .top
    newImageView.isUserInteractionEnabled = true


    let tap = UITapGestureRecognizer(target: self, action: #selector(dismissFullscreenImage))
    scrollView.addGestureRecognizer(tap)


    scrollView.delegate = self
    scrollView.minimumZoomScale = 1.0
    scrollView.maximumZoomScale = 3.0

    scrollView.addSubview(newImageView)

    self.view.addSubview(scrollView)
}

func viewForZooming(in scrollView: UIScrollView) -> UIView?
{
    return newImageView;
}

func dismissFullscreenImage(_ sender: UITapGestureRecognizer) {
    sender.view?.removeFromSuperview()
}

Answer 1

这里我正在以编程方式创建 ScrollView 和 ImageView ，这里img是一个PHAsset，我正在从图库中选择图像。

这是我正在做的事情，选择一个图像并移动到其他 View Controller ，然后根据我的 ImageView 调整该图像的大小所以缩放后图像不会模糊。

最小缩放受 ImageView 限制，最大缩放为 4.0。

func singleVC1()  {
        let v = UIView(frame: CGRect(x: 40, y: 50, width: self.view.frame.size.width - 80, height: view.frame.size.height - 200))
        let view1 = UIView(frame: CGRect(x: 0, y: 0, width: v.frame.size.width, height: v.frame.size.height/2 - 1))
        let scroll1 = UIScrollView.init(frame: view1.bounds)
        let imgview = UIImageView.init(frame: (CGRect)(origin: CGPoint.zero, size: self.returnAspectSize(targetWidth: view.frame.size.width, img: img)))
        self.setZoomScale(scrollview: scroll1, imageview: imgview)
        imgview.image = self.getUIImage(asset: img)
        scroll1.maximumZoomScale = 4.0;
        scroll1.delegate = self;
        scroll1.bounces = false
        scroll1.contentSize =  imgview.frame.size
        scroll1.addSubview(imgview)
        view1.layer.borderColor = UIColor.red.cgColor
        view1.layer.borderWidth = 5.0
        view1.addSubview(scroll1)
        v.addSubview(view1)

        let view2 = UIView(frame: CGRect(x: 0, y: v.frame.size.height/2+1, width: v.frame.size.width, height: v.frame.size.height/2 - 1))
        let scroll2 = UIScrollView.init(frame: view2.bounds)
        let imgview1 = UIImageView.init(frame: (CGRect)(origin: CGPoint.zero, size: self.returnAspectSize(targetWidth: view.frame.size.width, img: img)))
        imgview1.image = self.getUIImage(asset: img)
        self.setZoomScale(scrollview: scroll2, imageview: imgview1)
        scroll2.bounces = false

        scroll2.maximumZoomScale = 4.0;
        scroll2.delegate = self;
        view2.layer.borderColor = UIColor.red.cgColor
        view2.layer.borderWidth = 5.0
        scroll2.contentSize = imgview1.frame.size
        scroll2.addSubview(imgview1)
        view2.addSubview(scroll2)
        v.addSubview(view2)
        self.view.addSubview(v)
    }
func setZoomScale(scrollview : UIScrollView, imageview : UIImageView) {
        var minZoom = min(self.view.bounds.size.width / imageview.bounds.size.width, self.view.bounds.size.height / imageview.bounds.size.height);

        if (minZoom > 1.0) {
            minZoom = 1.0;
        }
        scrollview.minimumZoomScale = minZoom;
        scrollview.zoomScale = minZoom;
    }
    func returnAspectSize(targetWidth : CGFloat, img : PHAsset) -> CGSize {
        let img1 = self.getUIImage(asset: self.img)
        let targetwidth = targetWidth
        let scalefactor = (CGFloat)(targetwidth) / (CGFloat)((img1?.size.width)!)
        let targetheight = (img1?.size.height)! * scalefactor
        let targesize = CGSize(width: (CGFloat)(targetwidth), height: targetheight)
        return targesize
    }

试试这个。我相信这会对您有所帮助。