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.