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# CAMetalDisplayLinkDelegate

A protocol your app implements to respond to callbacks from Core Animation for a Metal display link.

```
protocol CAMetalDisplayLinkDelegate
```

## Overview

Your app responds to the system on behalf of a [`CAMetalDisplayLink`](/documentation/QuartzCore/CAMetalDisplayLink) with this protocol. Implement a type that adopts the protocol and assign an instance of it to a display link’s [`delegate`](/documentation/QuartzCore/CAMetalDisplayLink/delegate) property.

## Topics

### Receiving Display Updates

[`metalDisplayLink(_:needsUpdate:)`](/documentation/QuartzCore/CAMetalDisplayLinkDelegate/metalDisplayLink(_:needsUpdate:))

A method the system calls to notify your app when it plans to update the display.


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