---
title: "window(_:startCustomAnimationToEnterFullScreenWithDuration:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nswindowdelegate/window(_:startcustomanimationtoenterfullscreenwithduration:)"
---

# window(_:startCustomAnimationToEnterFullScreenWithDuration:)

This method is called to start the window animation into full-screen mode, including transitioning to a new space.

## Declaration

```swift
@MainActor optional func window(_ window: NSWindow, startCustomAnimationToEnterFullScreenWithDuration duration: TimeInterval)
```

## Parameters

- `window`: The window to enter full-screen mode.
- `duration`: The duration of the presentation change.

## Discussion

Discussion You can implement this method to perform custom animation with the given duration to be in sync with the system animation. Special Considerations This method is called only if customWindowsToEnterFullScreen(for:) returns non-nil.

## See Also

### Custom Full-Screen Presentation Animations

- [customWindowsToEnterFullScreen(for:)](appkit/nswindowdelegate/customwindowstoenterfullscreen(for:).md)
- [customWindowsToEnterFullScreen(for:on:)](appkit/nswindowdelegate/customwindowstoenterfullscreen(for:on:).md)
- [window(_:startCustomAnimationToEnterFullScreenOn:withDuration:)](appkit/nswindowdelegate/window(_:startcustomanimationtoenterfullscreenon:withduration:).md)
- [windowDidFailToEnterFullScreen(_:)](appkit/nswindowdelegate/windowdidfailtoenterfullscreen(_:).md)
- [customWindowsToExitFullScreen(for:)](appkit/nswindowdelegate/customwindowstoexitfullscreen(for:).md)
- [window(_:startCustomAnimationToExitFullScreenWithDuration:)](appkit/nswindowdelegate/window(_:startcustomanimationtoexitfullscreenwithduration:).md)
- [windowDidFailToExitFullScreen(_:)](appkit/nswindowdelegate/windowdidfailtoexitfullscreen(_:).md)