Ease
An event-driven animation system for Swift that combines the observer pattern with custom spring animations.
What is Ease?
Ease is a Swift library that provides an event-driven animation system, combining the observer pattern with custom spring animations to animate any value type. It solves the problem of creating smooth, natural animations in iOS and macOS apps by allowing dynamic updates to animation trajectories as target values change.
iOS and macOS developers building applications with complex UI animations, especially those using UIKit or SceneKit who need fluid, spring-based motion.
Developers choose Ease for its simplicity in creating dynamic spring animations, its support for multiple animations per value, and its ability to update trajectories on the fly, offering a more declarative and magical approach compared to traditional animation APIs.
Overview
It's magic.
Use Cases
Best For
- Creating smooth spring animations for UI elements in iOS apps
- Animating SceneKit 3D objects with natural physics
- Building gesture-driven interfaces with real-time animation updates
- Adding dynamic motion to custom value types in Swift
- Implementing complex animation sequences with multiple springs
- Optimizing animations for Swift 5 and modern iOS versions
Not Ideal For
- Projects exclusively using SwiftUI and preferring its native animation modifiers
- Applications with simple animation needs where UIView.animate or Core Animation suffices
- Teams needing cross-platform animation solutions beyond iOS and macOS
- Developers looking for built-in animation presets or drag-and-drop tools without coding
Pros & Cons
Pros
Animates a wide range of types including CGPoint, Int, and custom types, as shown in the README's supported list, making it flexible for various UI and SceneKit scenarios.
Allows real-time adjustment of target values mid-animation, enabling responsive interactions like gesture tracking, as demonstrated in the example code where targetValue is updated frequently.
Provides configurable tension, damping, and mass parameters to create natural spring effects, giving animations a realistic, fluid feel compared to basic easing curves.
Supports adding several spring animations to a single value, useful for complex effects such as combined motions or overlaying visual feedback, per the README's feature list.
Cons
Requires handling EaseDisposable and weak references to avoid retain cycles, adding boilerplate code and complexity compared to simpler, auto-managed animation APIs.
Primarily designed for UIKit and SceneKit with no mention of SwiftUI support, which may hinder adoption in modern projects favoring declarative UI frameworks.
Installation is only via CocoaPods, as stated in the README, which could be a barrier for projects using Swift Package Manager or Carthage exclusively.
Frequently Asked Questions
Related Projects
LottieAn iOS library to natively render After Effects vector animations
SpringA library to simplify iOS animations in Swift.
IBAnimatableDesign and prototype customized UI, interaction, navigation, transition and animation for App Store ready Apps in Interface Builder with IBAnimatable.
ViewAnimatorViewAnimator brings your UI to life with just one line
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