2 releases

Uses new Rust 2024

0.1.1 Jul 24, 2025
0.1.0 Jul 24, 2025

#1067 in Algorithms

MIT license

73KB
1.5K SLoC

Swift 771 SLoC // 0.2% comments Rust 485 SLoC // 0.0% comments

Respring

An open-source implementation of SwiftUI's Spring animation.

This repository aims to provide an interface and behavior identical to SwiftUI's native Spring implementation. This package allows you to use Spring to drive your animations without depending on SwiftUI.

Usage

Use Spring to convert between different representations of spring parameters:

let spring = Spring(duration: 0.5, bounce: 0.3)
let (mass, stiffness, damping) = (spring.mass, spring.stiffness, spring.damping)
// (1.0, 157.9, 17.6)


let spring2 = Spring(mass: 1, stiffness: 100, damping: 10)
let (duration, bounce) = (spring2.duration, spring2.bounce)
// (0.63, 0.5)

You can also use it to query for a spring’s position and its other properties for a given set of inputs:

func unitPosition(time: TimeInterval) -> Double {
    let spring = Spring(duration: 0.5, bounce: 0.3)
    return spring.position(target: 1.0, time: time)
}

Installation

Adding Respring to the dependencies value of your Package.swift or the Package list in Xcode.

dependencies: [
    .package(url: "https://github.com/ktiays/Respring.git", from: "1.0.0")
]

Normally you'll want to depend on the Respring target:

.product(name: "Respring", package: "Respring")

No runtime deps