# destinationImageRect(_:sourceImages:destinationImage:pluginState:at:) Calculates the bounds of the output image determined by the various inputs and plug-in state at the given render time. ``` func destinationImageRect(_ destinationImageRect: UnsafeMutablePointer, sourceImages: [FxImageTile], destinationImage: FxImageTile, pluginState: Data?, at renderTime: CMTime) throws ``` ## Parameters `destinationImageRect` The bounds of the output image. Your plug-in should calculate this value. `sourceImages` An array of images that represent the input images. They will have proper bounding rectangles and pixel transforms, but no pixel data will be given yet. `destinationImage` `pluginState` The `NSData` returned from your plug-in’s [`pluginState(_:at:quality:)`](/documentation/professional_video_applications/FxTileableEffect/pluginState(_:at:quality:)) method. `renderTime` The rational time at which the output will be rendered. ## Discussion This method is called when the plug-in wants to calculate the output bounds of your plug-in when rendering at a particular time. It will pass in an array of images, the plug-in state returned from your plug-in’s [`pluginState(_:at:quality:)`](/documentation/professional_video_applications/FxTileableEffect/pluginState(_:at:quality:)) method, and the render time. If your plug-in is unable to calculate the output rectangle at the given time, it should return `NO` and fill out the `outError` parameter with an `NSError` that uses the [`FxPlugErrorDomain`](/documentation/professional_video_applications/FxPlugErrorDomain) and appropriate (possibly custom) error code. --- 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)