Hi jmuffat,
As Frameworks Engineer has stated, you may want to look at
UIApplicationSupportsIndirectInputEvents if you haven't done so already.
By default,
UIPinchGestureRecognizer and
UIRotationGestureRecognizer use gesture simulating touches that start a fixed distance apart. These touches are then modified to simulate movement on the trackpad. Because of that, those touches can activate other gestures, which may be what is happening here.
If you adopt
UIApplicationSupportsIndirectInputEvents UIPinchGestureRecognizer and
UIRotationGestureRecognizer will be driven by a new event of type
UIEvent.EventType.transform with trackpad input, which will be much more precise.
My expectation is that the events get eaten by the system generating scroll events instead, but there doesn't seem to be any way to get those.
Scroll input is handled by
UIPanGestureRecognizer by updating its
allowedScrollTypesMask property. When you do that, you'll enable scroll input for your pan, and it will be driven by the event of type
UIEvent.EventType.scroll. If there are scroll events involved, it should be seeing those at this point.
Note that
UIEvent.EventType.transform and
UIEvent.EventType.scroll are *not* touch-based, so you won't get touches for either of these events. Some gotcha's are mentioned in the documentation Frameworks Engineer posted above related to this fact.
If you haven't already, you should check out this video on handling trackpad and mouse input, as it applies to both iPad and Catalyst:
https://developer.apple.com/videos/play/wwdc2020/10094/Hope that helps.
