SwiftBindings.Lottie

SwiftBindings.Lottie

Native Swift interop bindings for Lottie, Airbnb's library for rendering After Effects animations natively on iOS. These are not Objective-C proxy wrappers — they use .NET 10's native Swift interop for direct, high-performance calls into Swift APIs from C#.

Installation

dotnet add package SwiftBindings.Lottie

Requirements

• .NET 10.0+
• iOS 15.0+
• macOS host for development

Usage

Load and play an animation

using Lottie;

// Load from a bundled JSON file
var animation = LottieAnimation.Named("LoadingSpinner");

// Create the animation view and play
var animView = new LottieAnimationView();
animView.Animation = animation;
animView.LoopMode = LottieLoopMode.Loop;
animView.Play();

Playback control

// Play, pause, stop
animView.Play();
animView.Pause();
animView.Stop();

// Play a specific progress range
animView.Play(fromProgress: 0.0, toProgress: 0.5);

// Adjust speed and check state
animView.AnimationSpeed = 1.5;
var isPlaying = animView.IsAnimationPlaying;

// Scrub to a specific frame or progress
animView.CurrentProgress = 0.5;
animView.CurrentFrame = 30.0;
animView.ForceDisplayUpdate();

Animation properties

var animation = LottieAnimation.Named("Confetti");

var duration = animation.Duration;
var framerate = animation.Framerate;
var startFrame = animation.StartFrame;
var endFrame = animation.EndFrame;
var markers = animation.MarkerNames;

Cache management

var cache = DefaultAnimationCache.SharedCache;
cache.CacheSize = 50;

// Cache and retrieve animations
cache.SetAnimation(animation, "my-key");
var cached = cache.Animation("my-key");
cache.ClearCache();

Colors and value providers

// Create colors (RGBA 0.0-1.0)
var color = new LottieColor(1.0, 0.5, 0.25, 1.0);

// Or with 0-255 range
var color255 = new LottieColor(255.0, 128.0, 64.0, 255.0,
    ColorFormatDenominator.TwoFiftyFive);

// Dynamic value providers for animation properties
var floatProvider = new FloatValueProvider(0.75);
var sizeProvider = new SizeValueProvider((Swift.CGSize)new CGSize(100, 200));
var pointProvider = new PointValueProvider((Swift.CGPoint)new CGPoint(50, 75));

How It Works

These bindings are auto-generated by Swift Dotnet Bindings using .NET 10's native Swift interop via the SwiftBindings SDK.

Building from Source

Only needed if you're contributing or building the package locally.

# One-time: install the pinned Nuke CLI from .config/dotnet-tools.json
dotnet tool restore

# Build the package end-to-end (xcframework + bindings + dotnet build)
dotnet nuke BuildLibrary --library Lottie

License

The bindings are MIT licensed. Lottie itself is Apache 2.0 licensed — see Lottie's license.