1.Composition旋转动画

　　　　　　 var composition = ElementCompositionPreview.GetElementVisual(this).Compositor;

　　　　　　　//--------------------------------------------------------------------            // 1.创建一个ScalarAnimation和一个线性缓动函数。            //--------------------------------------------------------------------            var animation = composition.CreateScalarKeyFrameAnimation();            var easing = composition.CreateLinearEasingFunction();            //--------------------------------------------------------------------            // 1.设置动画，从0度旋转360度，3秒钟，重复播放            //--------------------------------------------------------------------            animation.InsertKeyFrame(0.0f,0.0f);            animation.InsertKeyFrame(1.0f,360.0f,easing);            animation.Duration = TimeSpan.FromMilliseconds(3000);            animation.IterationBehavior = AnimationIterationBehavior.Forever;

　　　　　　　//--------------------------------------------------------------------            // 1.获取button的Visual            // 2.开始动画，中心旋转            //--------------------------------------------------------------------            var buttonVisual = ElementCompositionPreview.GetElementVisual(AnimatingButton);            buttonVisual.CenterPoint = new Vector3((float)AnimatingButton.ActualWidth/2.0f,(float)AnimatingButton.ActualHeight/2.0f,0.0f);            buttonVisual.StartAnimation(nameof(buttonVisual.RotationAngleInDegrees),animation);