XAML-Map-Control/MapControl/Avalonia/MapImageLayer.Avalonia.cs

using Avalonia.Animation;
using Avalonia.Styling;
using System.Threading.Tasks;

namespace MapControl;

public partial class MapImageLayer
{
    private void FadeOver()
    {
        var fadeInAnimation = new Animation
        {
            FillMode = FillMode.Forward,
            Duration = MapBase.ImageFadeDuration,
            Children =
            {
                new KeyFrame
                {
                    KeyTime = MapBase.ImageFadeDuration,
                    Setters = { new Setter(OpacityProperty, 1d) }
                }
            }
        };

        _ = fadeInAnimation.RunAsync(Children[1]).ContinueWith(
            _ => Children[0].Opacity = 0d,
            TaskScheduler.FromCurrentSynchronizationContext());
    }
}