UIImageView 双指缩放 swift

Question

我希望有人能帮助我。我试图让用户在 UIImageView 上捏缩放（允许最大和最小级别）。但由于某种原因，它不能正常工作。图像放大一点然后反弹回来。谢谢。

这里是缩放功能

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

    }

}

Answer 1

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

为了设置 max/min 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!)

我也必须添加这个

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

Swift 3及以上函数原型

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

Answer 2

在我看来，问题出在你对currentScale的确定上。它始终等于 1，因为您更改了 imageView 的比例。您应该按如下方式分配 currentScale：

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

Answer 3

您可以使用 ImageScrollView 开源，一个可缩放和滚动的图像视图。 http://github.com/huynguyencong/ImageScrollView

喜欢这个开源，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()
    }
}

Answer 4

UIImageView 使用 UIScrollView 双指缩放 ||图片缩放 ios in swift 3 and Xcode 8 letter Youtube video URL

在故事板中设置 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
    }

Answer 5

我认为最大的问题是在你的func结尾，你有sender.scale = 1。如果您删除该行代码，您的图像不应该每次都反弹回来。

Answer 6

Swift3解

默认情况下 UIImageView's userInteration 被禁用。在 UIImageView.

中添加任何手势之前启用它

imgView.isUserInteractionEnabled = true

The scale factor relative to the points of the two touches in screen coordinates

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
  }
}

Answer 7

Swift 3 解

这是我使用的代码。我将 imageView 添加到 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
}

Answer 8

我在 Swift 中发布了一个关于缩放功能的答案 here 3。完美运行。

Answer 9

swift的选项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
  }
}

Answer 10

这是一个老问题，但我没有看到任何解释原始代码错误的答案。

这一行：

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

正在处理主视图而不是 imageView，因此比例计算始终为 ~1

这个简单的更改使其按预期运行

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

通过将 self 更改为 sender（并强制视图展开），缩放计算按预期工作。

Answer 11

我到这里了，可能是找错路了。

我在让我的 imageView 处于 contentMode = .centre 之后。但我认为它放大得太大了，我正在寻找一种缩小它的方法。方法如下：

    self.imageView.contentScaleFactor = 3

1 就像您在做任何事情一样。大于 1 缩小...3 适合我，但您需要对其进行测试。

Answer 12

使用 Swift 5.0，以下是我的工作方式：

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 来设置比例限制。

Answer 13

支持 Swift 5.1，您可以创建 UIImageView 的扩展，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
  }
}

UIImageView 双指缩放 swift

UIImageView pinch zoom swift

swift

uiimageview

uipinchgesturerecognizer