public ColorChangeableCanvas()
        {
            this.InitializeComponent();

            var watcher = new DependencyPropertyWatcher <Brush>(this, "Foreground");

            watcher.PropertyChanged += (s, e) =>
            {
                if (s is DependencyPropertyWatcher <Brush> w)
                {
                    ForegroundPropertyChanged(w.Value);
                }
            };

            win2DCanvas.CreateResources += (s, e) =>
            {
                // s is CanvasControl
                // e is CanvasCreateResourcesEventArgs
                e.TrackAsyncAction(CreateResourcesAsync(s).AsAsyncAction());
            };

            win2DCanvas.Draw += (s, e) =>
            {
                // s is CanvasControl
                // e is CanvasDrawEventArgs
                if (_bitmap is null)
                {
                    return;
                }
                if (IsLoadInProgress())
                {
                    return;
                }

                // ビットマップにエフェクトを掛ける
                Color c = _foreground; //colorPicker.Color;
                float r = c.R / 255.0f;
                float g = c.G / 255.0f;
                float b = c.B / 255.0f;
                var   colorMatrixEffect = new ColorMatrixEffect
                {
                    Source      = _bitmap,
                    ColorMatrix = new Matrix5x4
                    {
                        M11 = r, M12 = 0, M13 = 0, M14 = 0,
                        M21 = 0, M22 = g, M23 = 0, M24 = 0,
                        M31 = 0, M32 = 0, M33 = b, M34 = 0,
                        M41 = 0, M42 = 0, M43 = 0, M44 = 1,
                        M51 = 0, M52 = 0, M53 = 0, M54 = 0
                    },
                };

                // エフェクトを掛けた結果を表示する
                e.DrawingSession.DrawImage(colorMatrixEffect, 0, 0);

                // ※ ここでは、Win2D Canvas を UserControl の中に入れているため、表示サイズの調整が必要。
                this.Width  = _bitmap.Size.Width;
                this.Height = _bitmap.Size.Height;
            };
        }
        public static void OnPropertyChanged(object sender, DependencyPropertyChangedEventArgs args)
        {
            DependencyPropertyWatcher <T> source = (DependencyPropertyWatcher <T>)sender;

            source.PropertyChanged?.Invoke(source, EventArgs.Empty);
        }