Текст изменения кнопки клавиатуры "Return"

Вот пример UWP. Вы можете настроить его по своему усмотрению:

И код позади:

    private async void CreateVisuals()
    {
        var compositor = ElementCompositionPreview.GetElementVisual(this).Compositor;

        var bitmap = await CanvasBitmap.LoadAsync(CanvasDevice.GetSharedDevice(),
            new Uri("ms-appx:///Assets/Wave-PNG-Transparent-Picture.png"));

        var drawingSurface =
            CanvasComposition.CreateCompositionGraphicsDevice(compositor, CanvasDevice.GetSharedDevice())
                .CreateDrawingSurface(bitmap.Size,
                    DirectXPixelFormat.B8G8R8A8UIntNormalized, DirectXAlphaMode.Premultiplied);
        using (var ds = CanvasComposition.CreateDrawingSession(drawingSurface))
        {
            ds.Clear(Colors.Transparent);
            ds.DrawImage(bitmap);
        }

        var surfaceBrush = compositor.CreateSurfaceBrush(drawingSurface);
        surfaceBrush.Stretch = CompositionStretch.None;

        var maskedBrush = compositor.CreateMaskBrush();
        maskedBrush.Mask = Ellipse.GetAlphaMask();
        maskedBrush.Source = surfaceBrush;

        var sprite = compositor.CreateSpriteVisual();
        sprite.Size = new Vector2((float)Ellipse.Width, (float)Ellipse.Height);
        sprite.Brush = maskedBrush;
        sprite.CenterPoint = new Vector3(sprite.Size / 2, 0);
        sprite.Scale = new Vector3(0.9f);

        ElementCompositionPreview.SetElementChildVisual(VisualBorder, sprite);

        var offsetAnimation = compositor.CreateScalarKeyFrameAnimation();
        offsetAnimation.InsertKeyFrame(0, 0);
        offsetAnimation.InsertKeyFrame(1, 256, compositor.CreateLinearEasingFunction());
        offsetAnimation.Duration = TimeSpan.FromMilliseconds(1000);
        offsetAnimation.IterationBehavior = AnimationIterationBehavior.Forever;

        surfaceBrush.StartAnimation("Offset.X", offsetAnimation);
    }
}

Вот как это выглядит: