ValueAnimator

Lightweight value interpolation with easing functions for Apple platforms.

ValueAnimator transitions a value from from to to over time and reports each frame through a callback. You can animate a single property or multiple properties simultaneously.

Demo

Usage

Simple animation

let animator = ValueAnimator.animate(
    "rotation",
    from: 0,
    to: 360,
    duration: 1.0,
    easing: EaseCircular.easeIn(),
    onChanged: { property, value in
        print("property \(property): \(value.value)")
    }
)

animator.resume()

Multiple properties + yoyo

let animator = ValueAnimator.animate(
    props: ["h", "w"],
    from: [20, 30],
    to: [5, 150],
    duration: 1.4,
    easing: EaseSine.easeInOut(),
    onChanged: { property, value in
        if property == "h" {
            let width = self.rect1.bounds.width
            self.rect1.frame = CGRect(x: 24, y: 140, width: width, height: value.cg)
        } else {
            let height = self.rect1.bounds.height
            self.rect1.frame = CGRect(x: 24, y: 140, width: value.cg, height: height)
        }
    },
    option: ValueAnimator.OptionBuilder()
        .setYoyo(true)
        .setRepeatCount(2)
        .build())

animator.resume()

Completion callback

let animator = ValueAnimator.animate(
    props: ["alpha"],
    from: [0.0],
    to: [1.0],
    duration: 0.5,
    onEnd: {
        print("animation completed")
    }
)

animator.resume()

Callback thread

By default, changeCallback and endCallback are dispatched on the main thread. If you need callbacks on the animation engine thread, set callbackOnMainThread = false.

let animator = ValueAnimator.animate(
    "opacity",
    from: 0,
    to: 1,
    duration: 1.0,
    easing: EaseCircular.easeIn(),
    onChanged: { _, _ in
        // called on ValueAnimator engine thread
    },
)
animator.callbackOnMainThread = false
animator.resume()

Static controls

ValueAnimator.finishAll()
ValueAnimator.disposeAll()

Task {
    let isAnimating = await ValueAnimator.hasAnimation("opacity")
    print(isAnimating)
}

Example

To run the example project, clone the repo, and run open ValueAnimator.xcworkspace. You can see ValueAnimatorExample project.

Requirements

• iOS 13+
• tvOS 13+
• macOS 10.15+
• watchOS 6+

Installation

Swift Package Manager

• Open Xcode
• Go to File > Add Package Dependencies...
• Paste this repository URL:

https://github.com/brownsoo/ValueAnimator

• Select the ValueAnimator package and add it to your target.

CocoaPods

[!WARNING] CocoaPods support is now legacy and no longer actively updated. Please use Swift Package Manager for the latest updates.

Previously, you could add:

pod 'ValueAnimator'

Author

brownsoo, @medium

License

ValueAnimator is available under the MIT license. See the LICENSE file for more info.