たしかにキャンセルが検知されませんね。↓のような hacky なやり方はあるみたいですが・・・。 https://stackoverflow.com/questions/58807357/detect-draggesture-cancelation-in-swiftui

Detect DragGesture cancelation in SwiftUI

So I have a Rectangle with an added DragGesture and want to track gesture start, change and ending. The issue is when I put another finger on the Rectangle while performing the gesture, the first g...

4:24 AM

Apple のフォーラムで聞いてみるのが早いかもしれません。