previewController(_:transitionImageFor:contentRect:)
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, transitionImageFor item: any QLPreviewItem, contentRect: UnsafeMutablePointer<CGRect>) -> UIImage?Parameters
- controller:
The Qlpreviewcontroller that’s requesting the image for the preview item.
- item:
The item to preview or dismiss.
- contentRect:
The rectangle within the image that represents the document content. For icons, for example, the document content rectangle is typically smaller than the icon rectangle itself.
Return Value
A UIImage object that the preview controller cross-fades with when zooming.