XAML-Map-Control/MapControl/WPF/ImageTile.WPF.cs

using System;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Media.Imaging;

namespace MapControl;

public class ImageTile(int zoomLevel, int x, int y, int columnCount)
    : Tile(zoomLevel, x, y, columnCount)
{
    public Image Image { get; } = new Image { Stretch = Stretch.Fill };

    public override async Task LoadImageAsync(Func<Task<ImageSource>> loadImageFunc)
    {
        var image = await loadImageFunc().ConfigureAwait(false);

        void SetImageSource()
        {
            Image.Source = image;

            if (image != null && MapBase.ImageFadeDuration > TimeSpan.Zero)
            {
                if (image is BitmapSource bitmap && !bitmap.IsFrozen && bitmap.IsDownloading)
                {
                    bitmap.DownloadCompleted += BitmapDownloadCompleted;
                    bitmap.DownloadFailed += BitmapDownloadFailed;
                }
                else
                {
                    BeginFadeInAnimation();
                }
            }
        }

        await Image.Dispatcher.InvokeAsync(SetImageSource);
    }

    private void BeginFadeInAnimation()
    {
        var fadeInAnimation = new DoubleAnimation
        {
            From = 0d,
            Duration = MapBase.ImageFadeDuration,
            FillBehavior = FillBehavior.Stop
        };

        Image.BeginAnimation(UIElement.OpacityProperty, fadeInAnimation);
    }

    private void BitmapDownloadCompleted(object sender, EventArgs e)
    {
        var bitmap = (BitmapSource)sender;

        bitmap.DownloadCompleted -= BitmapDownloadCompleted;
        bitmap.DownloadFailed -= BitmapDownloadFailed;

        BeginFadeInAnimation();
    }

    private void BitmapDownloadFailed(object sender, ExceptionEventArgs e)
    {
        var bitmap = (BitmapSource)sender;

        bitmap.DownloadCompleted -= BitmapDownloadCompleted;
        bitmap.DownloadFailed -= BitmapDownloadFailed;

        Image.Source = null;
    }
}