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# NSAnimation.Curve

These constants describe the curve of an animation—that is, the relative speed of an animation from start to finish.

```
enum Curve
```

## Overview

You initialize an `NSAnimation` object using one of these constants with [`init(duration:animationCurve:)`](/documentation/AppKit/NSAnimation/init(duration:animationCurve:)) and you can set it thereafter with the [`animationCurve`](/documentation/AppKit/NSAnimation/animationCurve) property.

## Topics

### Constants

[`NSAnimation.Curve.easeInOut`](/documentation/AppKit/NSAnimation/Curve/easeInOut)

Describes an S-curve in which the animation slowly speeds up and then slows down near the end of the animation. This constant is the default.

[`NSAnimation.Curve.easeIn`](/documentation/AppKit/NSAnimation/Curve/easeIn)

Describes an animation that slows down as it reaches the end.

[`NSAnimation.Curve.easeOut`](/documentation/AppKit/NSAnimation/Curve/easeOut)

Describes an animation that slowly speeds up from the start.

[`NSAnimation.Curve.linear`](/documentation/AppKit/NSAnimation/Curve/linear)

Describes an animation in which there is no change in frame rate.


---

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