previewController(_:transitionViewFor:)
Tells the delegate that the system is about to present the preview full screen or dismiss it, and asks for information to provide a smooth transition when zooming.
Declaration
optional func previewController(_ controller: QLPreviewController, transitionViewFor item: any QLPreviewItem) -> UIView?Parameters
- controller:
The Qlpreviewcontroller that’s requesting the view for the preview item.
- item:
The item to preview or dismiss.
Return Value
A UIView object that the preview controller cross-fades with when zooming.
Discussion
Starting with macOS 11, animated transitions are available for Mac apps built with Mac Catalyst. On Mac computers running a version earlier than macOS 11, the system doesn’t call this delegate method.