WPF后台动画DoubleAnimation讲解

WPF后台动画，使用DoubleAnimation做的。

1.移动动画

需要参数（目标点离最上边的位置，目标点离最左边的位置，元素名称）

Image mImage = new Image();

FloatInElement(100,100,mImage);

 /// <summary>
         /// 移动动画
         /// </summary>
         /// <param name="top">目标点相对于上端的位置</param>
         /// <param name="left">目标点相对于左端的位置</param>
         /// <param name="elem">移动元素</param>
         public static void FloatInElement(double top, double left, UIElement elem)
         {
             try
             {
                 DoubleAnimation floatY = new DoubleAnimation()
                 {
                     To = TransValueFromHeight(top),
                     Duration = new TimeSpan(, , , , ),
                 };
                 DoubleAnimation floatX = new DoubleAnimation()
                 {
                     To = TransValueFromWidth(left),
                     Duration = new TimeSpan(, , , , ),
                 };

                 elem.BeginAnimation(Canvas.TopProperty, floatY);
                 elem.BeginAnimation(Canvas.LeftProperty, floatX);
             }
             catch (Exception)
             {

                 throw;
             }
         }

2.透明度动画

需要参数（元素名称,需要到达的透明度）

Image mImage = new Image();

FloatInElement(mImage,0);

 /// <summary>
         /// 透明度动画
         /// </summary>
         /// <param name="elem"></param>
         /// <param name="to"></param>
         public static void FloatElement(UIElement elem, double to)
         {
             lock (elem)
             {
                 if (to == )
                 {
                     elem.Visibility = Visibility.Visible;
                 }
                 DoubleAnimation opacity = new DoubleAnimation()
                 {
                     To = to,
                     Duration = new TimeSpan(, , , , )
                 };
                 EventHandler handler = null;
                 opacity.Completed += handler = (s, e) =>
                 {
                     opacity.Completed -= handler;
                     if (to == )
                     {
                         elem.Visibility = Visibility.Collapsed;
                     }
                     opacity = null;
                 };
                 elem.BeginAnimation(UIElement.OpacityProperty, opacity);
             }
         }

3.缓动动画-缩放动画

需要参数（控件名称,元素开始的位置，开始大小，目标大小）

Image mImage = new Image();

ScaleEasingAnimationShow(mImage,new Point(0.5,0.5),1,0);

元素开始的位置是从new Point（0，0）到new Point（1，1），左上角为（0，0）、右下角为（1，1），控件大小范围为（1，0） 1为控件本身大小，0 为控件缩放完，不显示。

如果要改动画类型，则改EasingMode = EasingMode.EaseOut

 /// <summary>
         /// 用户控件是的动画
         /// </summary>
         /// <param name="element">控件名</param>
         /// <param name="point">元素开始动画的位置</param>
         /// <param name="from">元素开始的大小</param>
         /// <param name="from">元素到达的大小</param>
         public static void ScaleEasingAnimationShow(FrameworkElement element, Point point, double from, double to)
         {
             lock (element)
             {
                 ScaleTransform scale = new ScaleTransform();
                 element.RenderTransform = scale;
                 element.RenderTransformOrigin = point;//定义圆心位置
                 EasingFunctionBase easeFunction = new PowerEase()
                 {
                     EasingMode = EasingMode.EaseOut,
                     Power =
                 };
                 DoubleAnimation scaleAnimation = new DoubleAnimation()
                 {
                     From = from,                                   //起始值
                     To = to,                                     //结束值
                     EasingFunction = easeFunction,                    //缓动函数
                     Duration = new TimeSpan(, , , , )  //动画播放时间
                 };
                 AnimationClock clock = scaleAnimation.CreateClock();
                 scale.ApplyAnimationClock(ScaleTransform.ScaleXProperty, clock);
                 scale.ApplyAnimationClock(ScaleTransform.ScaleYProperty, clock);
             }
         }