---
title: timingFunction
framework: quartzcore
role: symbol
role_heading: Instance Property
path: quartzcore/caanimation/timingfunction
---

# timingFunction

An optional timing function defining the pacing of the animation.

## Declaration

```swift
var timingFunction: CAMediaTimingFunction? { get set }
```

## Discussion

Discussion Defaults to nil, indicating linear pacing.

## See Also

### Animation Attributes

- [isRemovedOnCompletion](quartzcore/caanimation/isremovedoncompletion.md)