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iosswiftuiimageviewuipinchgesturerecognizer
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Reputation: 97

pinch gesture recognizer on expanded image

I have added a tap gesture recognizer action to my image view. Once the image is tapped it expands to full screen and then dismisses full screen once tapped again. How would I add pinch to zoom to the image after it is already expanded. Here is my code for making the image full screen.

//expand image


let newImageView: UIImageView!

@IBAction func imageTapped(_ sender: UITapGestureRecognizer)




{
    let imageView = sender.view as! UIImageView

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


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


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


    scrollView.delegate = self
    scrollView.minimumZoomScale = 1.0
    scrollView.maximumZoomScale = 5.0

    scrollView.addSubview(newImageView)

    self.view.addSubview(scrollView)
}

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

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

Upvotes: 1

Views: 783

Answers (2)

Luan Tran
Luan Tran

Reputation: 1142

When you wanna show full image, let use scrollview instead imageView

let 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 = .scaleAspectFit
    newImageView.isUserInteractionEnabled = true


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

    scrollView.delegate = self
    scrollView.minimumZoomScale = 1.0
    scrollView.maximumZoomScale = 5.0

    scrollView.addSubview(newImageView)
    self.view.addSubview(scrollView)
}

and remember viewForZooming delegate func 

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

Upvotes: 1

yao_seeeeeeeeeu
yao_seeeeeeeeeu

Reputation: 11

if you want to zoom the imageView, you should add the imageView on a UIScrollView and add the method below:

- (CGRect)zoomRectForScrollView:(UIScrollView *)scrollView withScale:(float)scale withCenter:(CGPoint)center {

    CGRect zoomRect;

    // The zoom rect is in the content view's coordinates.
    // At a zoom scale of 1.0, it would be the size of the
    // imageScrollView's bounds.
    // As the zoom scale decreases, so more content is visible,
    // the size of the rect grows.
    zoomRect.size.height = scrollView.frame.size.height / scale;
    zoomRect.size.width  = scrollView.frame.size.width  / scale;

    // choose an origin so as to get the right center.
    zoomRect.origin.x = center.x - (zoomRect.size.width  / 2.0);
    zoomRect.origin.y = center.y - (zoomRect.size.height / 2.0);

    return zoomRect;
}

for more detail :https://developer.apple.com/library/content/documentation/WindowsViews/Conceptual/UIScrollView_pg/ZoomZoom/ZoomZoom.html

Upvotes: 0

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