Ease is an event driven animation system that combines the observer pattern with custom spring animations as observers. It's magic.


  • [X] Animate any value type
  • [X] Set multiple animations for a single value
  • [X] Animation trajectories update when you update the targetValue
  • [X] Add natural spring behavior to any value change
  • [X] Optimized for Swift 5
  • [X] Compatible with iOS 9 and up

Supported value types

  • CGFloat
  • CGPoint
  • CGSize
  • CGVector
  • Int
  • Float
  • Double
  • SCNVector3

Easily extendible with more (custom) types.



Create your Ease object with an initial value

var ease: Ease<CGPoint> = Ease(view.center, minimumStep: 0.001)

Add your custom spring-animation(s)

ease.addSpring(tension: 300, damping: 15, mass: 1) { position in
    view.center = position

Set the target value of your Ease object and adjust your target as often as you want

ease.targetValue = gestureRecognizer.location(in: view)

Memory management

For a single spring-animation you can store the returned EaseDisposable to a variable

disposable = ease.addSpring(tension...

For multiple spring-animations you can add the disposable to a EaseDisposal variable

ease.addSpring(tension...) { }.add(to: &disposal)

And always weakify self when referencing self inside your spring-animation

ease.addSpring(tension...) { [weak self] position in


Ease is available through CocoaPods. To install
it, simply add the following line to your Podfile:

pod 'Ease'

Suggestions or feedback?

Feel free to create a pull request, open an issue or find me on Twitter.