alexandre-g / Easing

Easing functions in Swift 4

Easing in Swift

This project is composed of a stand-alone library of easing functions implemented in Swift 4 (Easing.swift).

Type of supported functions:

• Quadratic
• Cubic
• Quartic
• Quintic
• Sine
• Circular
• Exponential
• Elastic
• Back
• Bounce

Each type has its own separate ease-In, ease-Out and ease-In-Out form.

The functions are design to accept a generic floating-point value as time parameter,
and return a floating-point denoting the rate of change of a property over time.

Supported argument types:

• Float
• Double
• CGFloat

Usage

Add the file Easing.swift to your project and you are ready to go. The Curve type allows access to all the different functions, for example:

let x: Float = 0.3
let a = Curve.quadratic.easeIn(x)
// a = 0.09

let x2: CGFloat = 0.5
let b = Curve.sine.easeOut(x2)
// b = 0.7071067811865

Here's an example of the use of the elastic ease-in-out function in an array of 75 points in the [0, 1] interval.

Swift Package Manager support (for macOS and Linux)

You'll find a SPM ready version in the feature/SPMIntegration branch.

• To quickly generate a Xcode project, navigate to the project folder in the terminal and run:

  swift package generate-xcodeproj

  (In order to generate an Easing.xcodeprojfrom the project's Package.swift, be sure to have the Swift compiler installed and Swift added to your $PATH)

• To quickly run the tests:

  swift test