Pinch to zoom in and out on an image with UIScrollView

This is a sample of how to zoom in and out on an image in a UIScrollView.
Pinch to make the image larger or smaller.

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	import UIKit

	class ViewController: UIViewController, UIScrollViewDelegate {

	var scrollView: UIScrollView!
	var imageView: UIImageView!

	override func viewDidLoad() {
	super.viewDidLoad()

	scrollView = UIScrollView()
	scrollView.frame = self.view.frame
	scrollView.delegate = self
	scrollView.maximumZoomScale = 3.0
	scrollView.minimumZoomScale = 1.0
	self.view.addSubview(scrollView)

	imageView = UIImageView()
	imageView.image = UIImage(named: "snorlax")
	imageView.frame = scrollView.frame
	scrollView.addSubview(imageView)
	}

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