UIImageView捏缩放迅速

我希望有人可以帮助我。我试图允许用户捏UIImageView（允许最大和最小级别）上的缩放。但是由于某种原因，它无法正常工作。图像会稍微放大，然后反弹。谢谢。

这是变焦功能

func zoom(sender:UIPinchGestureRecognizer) {


    if sender.state == .Ended || sender.state == .Changed {

        let currentScale = self.view.frame.size.width / self.view.bounds.size.width
        var newScale = currentScale*sender.scale

        if newScale < 1 {
            newScale = 1
        }
        if newScale > 9 {
            newScale = 9
        }

        let transform = CGAffineTransformMakeScale(newScale, newScale)

        self.imageView?.transform = transform
        sender.scale = 1

    }

}

UIImageView用UIScrollView捏缩放 Swift 3和Xcode 8字母 Youtube视频URL中的图像缩放ios

在情节提要中设置uiscrollview委托

 class PhotoDetailViewController: UIViewController, UIScrollViewDelegate {

    @IBOutlet weak var scrollView: UIScrollView!
    @IBOutlet weak var imgPhoto: UIImageView!
      
    override func viewDidLoad() {
        
        super.viewDidLoad()
    
        scrollView.minimumZoomScale = 1.0
        scrollView.maximumZoomScale = 6.0        
        // scrollView.delegate = self - it is set on the storyboard.
    }  
        
    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
       
        return imgPhoto
    }

我决定将imageView添加到UIScrollView中。它允许用户缩放和平移。这是我使用的代码。

为了设置最大/最小缩放，我使用了：

    scrollImg.minimumZoomScale = 1.0
    scrollImg.maximumZoomScale = 10.0

这是其余的代码。

    var vWidth = self.view.frame.width
    var vHeight = self.view.frame.height

    var scrollImg: UIScrollView = UIScrollView()
    scrollImg.delegate = self
    scrollImg.frame = CGRectMake(0, 0, vWidth!, vHeight!)
    scrollImg.backgroundColor = UIColor(red: 90, green: 90, blue: 90, alpha: 0.90)
    scrollImg.alwaysBounceVertical = false
    scrollImg.alwaysBounceHorizontal = false
    scrollImg.showsVerticalScrollIndicator = true
    scrollImg.flashScrollIndicators()

    scrollImg.minimumZoomScale = 1.0
    scrollImg.maximumZoomScale = 10.0

    defaultView!.addSubview(scrollImg)

    imageView!.layer.cornerRadius = 11.0
    imageView!.clipsToBounds = false
    scrollImg.addSubview(imageView!)

我也必须添加它

func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
    return self.imageView
}

Swift 3及以上功能原型

func viewForZooming(in scrollView: UIScrollView) -> UIView? {
    return self.mainImage
}

支持Swift 5.1，您可以创建的扩展UIImageView，如下所示：

extension UIImageView {
  func enableZoom() {
    let pinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(startZooming(_:)))
    isUserInteractionEnabled = true
    addGestureRecognizer(pinchGesture)
  }

  @objc
  private func startZooming(_ sender: UIPinchGestureRecognizer) {
    let scaleResult = sender.view?.transform.scaledBy(x: sender.scale, y: sender.scale)
    guard let scale = scaleResult, scale.a > 1, scale.d > 1 else { return }
    sender.view?.transform = scale
    sender.scale = 1
  }
}

快速选项4

class ViewController: UIViewController, UIScrollViewDelegate {

@IBOutlet weak var scrolView: UIScrollView!
@IBOutlet weak var imgPhoto: UIImageView!

  override func viewDidLoad() {
    super.viewDidLoad()
    scrolView.delegate = self
    scrolView.minimumZoomScale = 1.0
    scrolView.maximumZoomScale = 10.0
  }

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

您可以使用ImageScrollView开源，可缩放和可滚动的图像视图。http://github.com/huynguyencong/ImageScrollView

像这个开源程序一样，将ImageView添加到ScrollView

open class ImageScrollView: UIScrollView {
   var zoomView: UIImageView? = nil
}

extension ImageScrollView: UIScrollViewDelegate{

    public func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return zoomView
    }

    public func scrollViewDidZoom(_ scrollView: UIScrollView) {
        adjustFrameToCenter()
    }
}

我认为问题在于您对currentScale的确定。它始终等于1，因为您更改了imageView的比例。您应按以下方式分配currentScale：

let currentScale = self.imageView?.frame.size.width / self.imageView?.bounds.size.width  

Swift 3解决方案

默认情况下UIImageView's userInteration处于禁用状态。在中添加任何手势之前将其启用UIImageView。

imgView.isUserInteractionEnabled = true

相对于屏幕坐标中两次触摸的点的比例因子

var lastScale:CGFloat!
func zoom(gesture:UIPinchGestureRecognizer) {
    if(gesture.state == .began) {
        // Reset the last scale, necessary if there are multiple objects with different scales
        lastScale = gesture.scale
    }
    if (gesture.state == .began || gesture.state == .changed) {
    let currentScale = gesture.view!.layer.value(forKeyPath:"transform.scale")! as! CGFloat
    // Constants to adjust the max/min values of zoom
    let kMaxScale:CGFloat = 2.0
    let kMinScale:CGFloat = 1.0
    var newScale = 1 -  (lastScale - gesture.scale)
    newScale = min(newScale, kMaxScale / currentScale)
    newScale = max(newScale, kMinScale / currentScale)
    let transform = (gesture.view?.transform)!.scaledBy(x: newScale, y: newScale);
    gesture.view?.transform = transform
    lastScale = gesture.scale  // Store the previous scale factor for the next pinch gesture call
  }
}

使用Swift 5.0，这对我来说是这样的：

let myImageView = UIImageView(image: myImage)
myImageView.isUserInteractionEnabled = true
let pinchMethod = UIPinchGestureRecognizer(target: self, action: #selector(pinchImage(sender:)))
myImageView.addGestureRecognizer(pinchMethod)

@objc func pinchImage(sender: UIPinchGestureRecognizer) {
  guard let sender.view != nil else { return }

if let scale = (sender.view?.transform.scaledBy(x: sender.scale, y: sender.scale)) {
  guard scale.a > 1.0 else { return }
  guard scale.d > 1.0 else { return }
  sender.view?.transform = scale
  sender.scale = 1.0
 }
}

您可以使用scale.a，scale.b，scale.c，scale.d，scale.tx和scale.ty来设置规模限制。

Swift 3解决方案

这是我使用的代码。我添加了imageView到scrollView作为子视图。

class ZoomViewController: UIViewController,UIScrollViewDelegate {

@IBOutlet weak var scrollView:UIScrollView!
@IBOutlet weak var imageView:UIImageView!

override func viewDidLoad() {

        super.viewDidLoad()
        scrollView.delegate = self

        scrollView.minimumZoomScale = 1.0
        scrollView.maximumZoomScale = 10.0//maximum zoom scale you want
        scrollView.zoomScale = 1.0

}

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

我认为最大的问题是你的最后func，你有sender.scale = 1。如果您删除该行代码，则图像不应每次都反弹。

我在这里发布了有关在Swift 3中同时进行缩放和双击缩放功能的答案。

这是一个古老的问题，但是我看不到任何答案来解释原始代码有什么问题。

这行：

let currentScale = self.view.frame.size.width / self.view.bounds.size.width

正在主视图而不是imageView上工作，因此比例计算始终为〜1

这个简单的更改使其表现出预期

let currentScale = sender.view!.frame.size.width / sender.view!.bounds.size.width

通过将自身更改为发件人（并强制视图展开），比例计算将按预期进行。

我到这里结束，可能是搜索错误的方式。

我将imageView设置为contentMode = .centre之后。但是我判断它也放大了，我正在寻找一种缩小它的方法。这是如何做：

    self.imageView.contentScaleFactor = 3

1就像您在做什么一样。1缩小更多... 3适用于我，但您需要对其进行测试。