UIPageViewControllerDelegate
The delegate of a page view controller must adopt the Uipageviewcontrollerdelegate protocol. These methods allow the delegate to receive a notification when the device orientation changes and when the user navigates to a new page. For page-curl style transitions, the delegate can provide a different spine location in response to a change in the interface orientation.
Declaration
@MainActor protocol UIPageViewControllerDelegate : NSObjectProtocolTopics
Responding to Page View Controller Events
pageViewController(_:willTransitionTo:)pageViewController(_:didFinishAnimating:previousViewControllers:transitionCompleted:)pageViewController(_:spineLocationFor:)