# easeInEaseOut Ease-in-ease-out pacing, which causes an animation to begin slowly, accelerate through the middle of its duration, and then slow again before completing. ``` static let easeInEaseOut: CAMediaTimingFunctionName ``` ## Discussion This is a Bézier timing function with the control points (0.42,0.0) and (0.58,1.0). The following code shows how to create a basic animation object using ease-in-ease-out interpolation. ```swift let verticalAnimation = CABasicAnimation(keyPath: "position.y") verticalAnimation.fromValue = 310 verticalAnimation.toValue = 10 verticalAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) ``` A layer animated with the animation created by the code above and with linearly interpolated horizontal movement would describe a path similar to the following figure.  --- 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)