how to pinch zoom in on code created scrollview - swift

Question

My code creates a scrollview and image view that displays a picture array from a previous view controller. However, I am trying to implement code to make it so the user may zoom in on a picture. But what ever I do, it does not work. Any suggestions on what I am doing wrong, or where to implement the zoom in code? Thank you!
import UIKit
class DestinationVC: UIViewController {
#IBOutlet weak var myScrollView: UIScrollView!
var mySelectedProtocol:Protocol?
var pageControl:UIPageControl?
var currentPageIndex:Int=0
fileprivate var count:Int=0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
if mySelectedProtocol == nil { self.navigationController?.popViewController(animated: true) }
if mySelectedProtocol!.imagesName!.count == 0 { self.navigationController?.popViewController(animated: true) }
/// We have Data
print("Img Array with Name ==> \(mySelectedProtocol?.imagesName ?? [])")
DispatchQueue.main.async {
self.addPageView()
}
}
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
myScrollView.delegate = self
myScrollView.minimumZoomScale = 1.0
myScrollView.maximumZoomScale = 5.0
return myScrollView
}
private func addPageView() {
myScrollView.backgroundColor=UIColor.black
myScrollView.isUserInteractionEnabled=true
myScrollView.showsHorizontalScrollIndicator=true
myScrollView.isPagingEnabled=true
myScrollView.delegate=self
myScrollView.bounces=false
self.count=mySelectedProtocol!.imagesName!.count
for i in 0..<self.count {
///Get Origin
let xOrigin : CGFloat = CGFloat(i) * myScrollView.frame.size.width
///Create a imageView
let imageView = UIImageView()
imageView.frame = CGRect(x: xOrigin, y: 0, width: myScrollView.frame.size.width, height: myScrollView.frame.size.height)
imageView.contentMode = .scaleAspectFit
imageView.image=UIImage(named: mySelectedProtocol!.imagesName![i])
myScrollView.addSubview(imageView)
}
setUpPageControl()
///Set Content Size to Show
myScrollView.contentSize = CGSize(width: myScrollView.frame.size.width * CGFloat(self.count), height: myScrollView.frame.size.height)
}
private func setUpPageControl() {
if pageControl == nil { pageControl=UIPageControl() }
pageControl!.numberOfPages = self.count
pageControl!.currentPageIndicatorTintColor = UIColor.red
pageControl!.pageIndicatorTintColor = UIColor.white
pageControl!.frame = CGRect(x: 0, y: 20, width: self.view.frame.width, height: self.view.frame.height*0.2)
pageControl!.currentPage=currentPageIndex
self.view.addSubview(pageControl!)
self.view.bringSubview(toFront: pageControl!)
}
}
extension DestinationVC: UIScrollViewDelegate {
func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
let scrollW : CGFloat = scrollView.frame.size.width
currentPageIndex = Int(scrollView.contentOffset.x / scrollW)
self.pageControl!.currentPage=currentPageIndex
}
func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
let scrollW : CGFloat = scrollView.frame.size.width
currentPageIndex = Int(scrollView.contentOffset.x / scrollW)
self.pageControl!.currentPage=currentPageIndex
}
}

Answer 1

You set the minimumScale to 1.0 - that's just 1x the normal scale. If you want it to be zoom down closer, you could try setting the minimum zoom like this:
let scaleWidth = scrollView.frame.size.width / scrollView.contentSize.width
let scaleHeight = scrollView.frame.size.height / scrollView.contentSize.height
let minScale = min(scaleWidth, scaleHeight)
scrollView.minimumZoomScale = minScale
scrollView.maximumZoomScale = 1.0
scrollView.zoomScale = minScale
And set the maximumZoomScale to 1.0 - the size of the content.