Table of Contents

Standalone animations

Xaml.Behaviors.Animations is the reusable animation layer for this repository. It targets net8.0 and net10.0, depends only on Avalonia, and does not reference Xaml.Behaviors.Interactivity or any interactions package.

Install it when an application or library needs the animation implementations without behavior, action, or trigger types:

<PackageReference Include="Xaml.Behaviors.Animations" Version="..." />

The repository includes an animations-only sample application with a dedicated tab for every feature family. Its project references only Avalonia and Xaml.Behaviors.Animations.

API groups

Group APIs
Avalonia key-frame animation AnimationFactory, AnimationRunner, FluidMoveAnimation, IAnimationBuilder
Composition catalogs AttentionAnimations, EntranceAnimations, ExitAnimations, FramerMotionAnimations, SpecialAnimations
Composition primitives FadeAnimation, RotateAnimation, ScaleAnimation, SlidingAnimation
Reusable effects OrbitAnimation, ParallaxAnimation, TiltAnimation
Selection animation SelectionIndicatorAnimation, SelectingItemsControlBehavior attached property
Transitions TransitionOperations

The CLR namespace remains Avalonia.Xaml.Interactions.Custom for source and XAML compatibility with earlier releases. The types now live in the Xaml.Behaviors.Animations assembly, while Xaml.Behaviors.Interactions.Custom ships type forwarders for legacy assembly-qualified references.

XAML composition animations

The composition catalogs are attached properties, so they can be used with no behavior collection:

<UserControl
    xmlns="https://github.com/avaloniaui"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:animations="using:Avalonia.Xaml.Interactions.Custom">
  <Border
      Width="220"
      Height="150"
      animations:EntranceAnimations.FadeInUp="800" />
</UserControl>

The attached values are durations in milliseconds. The animation begins when the element receives a composition visual. A zero duration applies the final key-frame state immediately; a positive duration runs through the compositor.

Direct use from code

Create and run a normal Avalonia animation. Async variants return the completion task when callers need to coordinate follow-up work:

using Avalonia.Controls;
using Avalonia.Xaml.Interactions.Custom;

public static class WelcomeAnimation
{
    public static void Start(Control target)
    {
        var animation = AnimationFactory.CreateFadeIn(
            TimeSpan.FromMilliseconds(150),
            TimeSpan.FromMilliseconds(350));

        AnimationRunner.TryRun(animation, target);
    }
}

AnimationRunner.TryBuildAndRunAsync applies the same explicit-animation-first selection used by the behavior adapters and returns null when neither an animation nor a builder result is available. FluidMoveAnimation.TryRun prepares a control's translation transform before starting its movement animation.

Composition effects expose calculation and application separately where useful. For example, a scroll observer can retain a session from ParallaxAnimation.TryCreate(target) and call its Apply(offset, ratio) method without attaching ParallaxBehavior. The session preserves the target composition visual across scroll updates and adds each parallax delta to the target's layout offset. OrbitAnimation maintains its orientation state for callers, while TiltAnimation calculates an orientation directly from the target size and pointer position.

SelectionIndicatorAnimation.TryStart can animate explicitly supplied indicator/container visuals or resolve the conventional PART_SelectedPipe from two templated item containers. SelectingItemsControlBehavior.EnableSelectionAnimation is the convenient attached-property adapter over the same primitive.

Transition collection operations are likewise independent:

var transition = new DoubleTransition
{
    Property = Visual.OpacityProperty,
    Duration = TimeSpan.FromMilliseconds(200)
};

TransitionOperations.Add(target, transition);

using IDisposable subscription = TransitionOperations.Observe(
    target,
    transitions => OnTransitionsReplaced(transitions));

Observe reports the current collection immediately and subsequent replacements until the returned subscription is disposed.

Behavior adapters

Install Xaml.Behaviors.Interactions.Custom when XAML attachment lifecycle, triggers, or actions are desired. Its animation and transition adapters reference Xaml.Behaviors.Animations and use the same shared implementation; existing behavior XAML remains unchanged.

Edit this page