# previewPanel(_:transitionImageFor:contentRect:) Returns the image to use for the transition zoom effect for a given item. ``` optional func previewPanel(_ panel: QLPreviewPanel!, transitionImageFor item: (any QLPreviewItem)!, contentRect: UnsafeMutablePointer!) -> Any! ``` ## Parameters `panel` The preview panel. `item` The item the system is previewing. `contentRect` The rectangle within a preview image that actually represents the content of the document. For icons, the actual rectangle is typically smaller than the icon itself. ## Return Value The image to use for the transition zoom effect for the `item`. ## Discussion The system invokes this optional method when the preview panel opens or closes to provide a smooth transition when zooming. The return type of the function should be an instance of . --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)