Add scrollview over mapview to capture pinch / zoom gestures

I’d like my users to use pinch to set the radius of their geofence.
I know I can disable user interaction on the mapView like this:
mapView.isUserInteractionEnabled = false
but that only solves part of the problem.

I remember seeing a tutorial here where they put a scrollview OVER the mapview to intercept the user gestures.
I think it was a tile-game example but I can’t seem to find it
Yeah, it was scrollview over tiles, not over a map…
…can someone point me to it so I can review that technique??