---
title: "sessionControlsWillEnterFullscreenAppearance(_:)"
framework: avfoundation
role: symbol
role_heading: Instance Method
path: "avfoundation/avcapturesessioncontrolsdelegate/sessioncontrolswillenterfullscreenappearance(_:)"
---

# sessionControlsWillEnterFullscreenAppearance(_:)

Tells the delegate when a capture session’s controls are about to enter a fullscreen appearance.

## Declaration

```swift
func sessionControlsWillEnterFullscreenAppearance(_ session: AVCaptureSession)
```

## Parameters

- `session`: The capture session with controls that are entering a fullscreen appearance.

## Discussion

Discussion When controls enter a fullscreen appearance, your app should hide portions of its user interface, including duplicative or unnecessary elements. Few onscreen elements should be visible so people can focus on their control interactions while viewing the camera preview unobstructed.

## See Also

### Responding to control events

- [sessionControlsDidBecomeActive(_:)](avfoundation/avcapturesessioncontrolsdelegate/sessioncontrolsdidbecomeactive(_:).md)
- [sessionControlsWillExitFullscreenAppearance(_:)](avfoundation/avcapturesessioncontrolsdelegate/sessioncontrolswillexitfullscreenappearance(_:).md)
- [sessionControlsDidBecomeInactive(_:)](avfoundation/avcapturesessioncontrolsdelegate/sessioncontrolsdidbecomeinactive(_:).md)