Simultaneous Gestures not working for a ZoomableScrollView in SwiftUI - swiftui

Question

Using Swift5.3.2, iOS14.4.1, Xcode12.4,
I am trying to use the .simultaneousGesture modifier in SwiftUI.
As far as I understood, this modifier should make sure that gestures (such as tap, longpress, magnification etc) should be able to co-exist within a View.
In my example I am using a ZoomableScrollView. And it works fine as long as I do not use the simultaneousGesture.
But as soon as I use the extra simultaneousGesture, the ZoomableScrollView is no longer "zoomable" (i.e. none of its gestures work anymore).
What can I do to make the zoom still work AND get an extra dragGesture ?
import SwiftUI
struct MediaTabView: View {
#GestureState private var dragOffset: CGFloat = -100
var body: some View {
ZoomableScrollView {
Image(uiImage: UIImage(contentsOfFile: url.path)!)
.resizable()
.scaledToFit()
}
}
.frame(maxWidth: .infinity, maxHeight: .infinity)
.background(Color.black)
.simultaneousGesture(
DragGesture()
.updating($dragOffset) { (value, gestureState, transaction) in
let delta = value.location.x - value.startLocation.x
if delta > 10 { // << some appropriate horizontal threshold here
gestureState = delta
print(delta)
}
}
.onEnded {
if $0.translation.width > 100 {
// Go to the previous slide
print("on ended")
}
}
)
}
}
The code for the ZoomableScrollView is here :
import SwiftUI
struct ZoomableScrollView<Content: View>: UIViewRepresentable {
private var content: Content
init(#ViewBuilder content: () -> Content) {
self.content = content()
}
func makeUIView(context: Context) -> UIScrollView {
// set up the UIScrollView
let scrollView = UIScrollView()
scrollView.delegate = context.coordinator // for viewForZooming(in:)
scrollView.maximumZoomScale = 20
scrollView.minimumZoomScale = 1
scrollView.bouncesZoom = true
// create a UIHostingController to hold our SwiftUI content
let hostedView = context.coordinator.hostingController.view!
hostedView.translatesAutoresizingMaskIntoConstraints = true
hostedView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
hostedView.frame = scrollView.bounds
hostedView.backgroundColor = .black
scrollView.addSubview(hostedView)
return scrollView
}
func makeCoordinator() -> Coordinator {
return Coordinator(hostingController: UIHostingController(rootView: self.content))
}
func updateUIView(_ uiView: UIScrollView, context: Context) {
// update the hosting controller's SwiftUI content
context.coordinator.hostingController.rootView = self.content
assert(context.coordinator.hostingController.view.superview == uiView)
}
// MARK: - Coordinator
class Coordinator: NSObject, UIScrollViewDelegate {
var hostingController: UIHostingController<Content>
init(hostingController: UIHostingController<Content>) {
self.hostingController = hostingController
}
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return hostingController.view
}
}
}