稳扎稳打Silverlight(37) - 3.0动画之Easing（缓动效果）

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稳扎稳打Silverlight(37) - 3.0动画之Easing（缓动效果）

作者：webabcd


介绍
Silverlight 3.0 动画的缓动效果：

• Easing 可以与 Storyboard 结合实现动画的缓动效果
• Silverlight 3 内置 11 种缓动效果：分别为BackEase, BounceEase, CircleEase, CubicEase, ElasticEase, ExponentialEase, PowerEase, QuadraticEase, QuarticEase, QuinticEase, SineEase
• 各个缓动类都继承自 EasingFunctionBase，除了 EasingFunctionBase 提供的功能外，各个缓动类可能还会有各自的属性（懒的写了，查文档吧） 
• EasingFunctionBase 有一个用于设置缓动模式的枚举类型属性 EasingMode （EasingMode.EaseOut(默认值), EasingMode.EaseIn, EasingMode.EaseInOut）

在线DEMO
http://www.cnblogs.com/webabcd/archive/2009/08/04/1538238.html


示例
1、Silverlight 3.0 内置的 11 种缓动效果的 Demo
Easing.xaml

<navigation:Page x:Class="Silverlight30.Animation.Easing" 
           xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
           xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
           xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
           xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
           mc:Ignorable="d"
           xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
           d:DesignWidth="640" d:DesignHeight="480"
           Title="Easing Page">
    <Grid x:Name="LayoutRoot">
        <StackPanel Orientation="Horizontal" HorizontalAlignment="Left">

            <!--用于显示各种 Easing 的图例列表-->
            <StackPanel Margin="10">
                <ListBox x:Name="lstEasing">
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <StackPanel Margin="1">
                                <TextBlock Text="{Binding EasingName}" />
                                <Image Source="{Binding PicAddress}" Width="300" Height="50" />
                            </StackPanel>
                        </DataTemplate>
                    </ListBox.ItemTemplate>
                </ListBox>
            </StackPanel>

            <StackPanel Margin="10, 200">
           
                <!--分别用 3 种动画来演示各类 Easing-->
                <ComboBox x:Name="cboTransform" Margin="5">
                    <ComboBoxItem Content="Translate" IsSelected="True" />
                    <ComboBoxItem Content="Rotate" />
                    <ComboBoxItem Content="Scale" />
                </ComboBox>
                
                <!--用各种 EasingMode 分别做演示-->
                <ComboBox x:Name="cboEasingMode" Margin="5">
                    <ComboBoxItem Content="EaseOut" IsSelected="True" />
                    <ComboBoxItem Content="EaseIn" />
                    <ComboBoxItem Content="EaseInOut" />
                </ComboBox>

                <Button x:Name="btnShow" Content="演示" Click="btnShow_Click" Margin="5" />

                <!--用于做动画演示的矩形-->
                <Rectangle x:Name="rect" Fill="Blue" Width="200" Height="40" Margin="5" RenderTransformOrigin="0.5,0.5">
                    <Rectangle.RenderTransform>
                        <TransformGroup>
                            <TranslateTransform x:Name="tt" X="0" Y="0" />
                            <RotateTransform x:Name="rt" Angle="0" />
                            <ScaleTransform x:Name="st" ScaleX="1" ScaleY="1" />
                        </TransformGroup>
                    </Rectangle.RenderTransform>
                </Rectangle>

            </StackPanel>
        </StackPanel>
    </Grid>
</navigation:Page>

Easing.xaml.cs

/**//*
 * Easing - 与 Storyboard 结合实现动画的缓动效果
 * Silverlight 3 内置 11 种缓动效果：分别为BackEase, BounceEase, CircleEase, CubicEase, ElasticEase, ExponentialEase, PowerEase, QuadraticEase, QuarticEase, QuinticEase, SineEase
 * 各个缓动类都继承自 EasingFunctionBase，除了 EasingFunctionBase 提供的功能外，各个缓动类可能还会有各自的属性（懒的写了，查文档吧）
 * EasingFunctionBase 有一个用于设置缓动模式的枚举类型属性 EasingMode （EasingMode.EaseOut(默认值), EasingMode.EaseIn, EasingMode.EaseInOut）
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Navigation;

using Silverlight30.Model;
using System.Xml.Linq;

namespace Silverlight30.Animation
{
    public partial class Easing : Page
    {
        public Easing()
        {
            InitializeComponent();

            this.Loaded += new RoutedEventHandler(Easing_Loaded);
        }

        // 绑定各种 Easing 的图例列表
        void Easing_Loaded(object sender, RoutedEventArgs e)
        {
            XElement root = XElement.Load("Animation/Easing.xml");
            var easings = from n in root.Elements("easing")
                          select new EasingModel
                          {
                              EasingName = (string)n.Attribute("EasingName"),
                              Description = (string)n.Attribute("Description"),
                              PicAddress = (string)n.Attribute("PicAddress")
                          };

            lstEasing.ItemsSource = easings;
            lstEasing.SelectedIndex = 0;
        }

        private Storyboard _prevStoryboard;

        private void btnShow_Click(object sender, RoutedEventArgs e)
        {
            if (_prevStoryboard != null)
                _prevStoryboard.Stop();

            // 实例化用户所选择的 Easing
            Type type = typeof(EasingFunctionBase).Assembly.GetType("System.Windows.Media.Animation." + ((EasingModel)lstEasing.SelectedItem).EasingName, false);
            EasingFunctionBase easing = Activator.CreateInstance(type) as EasingFunctionBase;

            // 根据用户的选择，设置 Easing 的 EasingMode 属性
            easing.EasingMode = (EasingMode)Enum.Parse(typeof(EasingMode), ((ComboBoxItem)cboEasingMode.SelectedItem).Content.ToString(), true);

            Storyboard sb = new Storyboard();
            _prevStoryboard = sb;

            var transformType = ((ComboBoxItem)cboTransform.SelectedItem).Content.ToString();
            switch (transformType)
            {
                // 位移动画结合 Easing 的演示
                case "Translate":
                    DoubleAnimation daTranslateY = new DoubleAnimation();
                    daTranslateY.From = 0 ;
                    daTranslateY.To = 200;
                    daTranslateY.Duration = TimeSpan.FromSeconds(3);

                    daTranslateY.EasingFunction = easing;

                    Storyboard.SetTargetProperty(daTranslateY, new PropertyPath("Y"));
                    Storyboard.SetTarget(daTranslateY, tt);

                    sb.Children.Add(daTranslateY);

                    break;
                // 缩放动画结合 Easing 的演示
                case "Scale":
                    DoubleAnimation daScaleX = new DoubleAnimation();
                    daScaleX.From = 1;
                    daScaleX.To = 2;
                    daScaleX.Duration = TimeSpan.FromSeconds(3);

                    DoubleAnimation daScaleY = new DoubleAnimation();
                    daScaleY.From = 1;
                    daScaleY.To = 2;
                    daScaleY.Duration = TimeSpan.FromSeconds(3);

                    daScaleX.EasingFunction = easing;
                    daScaleY.EasingFunction = easing;

                    Storyboard.SetTargetProperty(daScaleX, new PropertyPath("ScaleX"));
                    Storyboard.SetTarget(daScaleX, st);
                    Storyboard.SetTargetProperty(daScaleY, new PropertyPath("ScaleY"));
                    Storyboard.SetTarget(daScaleY, st);

                    sb.Children.Add(daScaleX);
                    sb.Children.Add(daScaleY);

                    break;
                // 旋转动画结合 Easing 的演示
                case "Rotate":
                    DoubleAnimation daAngle = new DoubleAnimation();
                    daAngle.To = 0;
                    daAngle.To = 360;
                    daAngle.Duration = TimeSpan.FromSeconds(3);

                    daAngle.EasingFunction = easing;

                    Storyboard.SetTargetProperty(daAngle, new PropertyPath("Angle"));
                    Storyboard.SetTarget(daAngle, rt);

                    sb.Children.Add(daAngle);

                    break;
            }
   
            sb.Begin();
        }
    }
}

2、自定义缓动效果的 Demo
MyCustomEasing.cs

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace Silverlight30.Animation
{
    /**//// <summary>
    /// 自定义缓动效果
    /// </summary>
    public class MyCustomEasing : EasingFunctionBase
    {
        public MyCustomEasing()
            : base()
        {
 
        }

        /**//// <summary>
        /// 实现 EaseIn 模式下的逻辑
        /// EaseOut 和 EaseInOut 会自动实现
        /// </summary>
        /// <param name="normalizedTime">标准时间位（0 - 1之间）。即 动画运行到此的时间 占 动画运行所需的全部时间 的百分比</param>
        /// <returns></returns>
        protected override double EaseInCore(double normalizedTime)
        {
            // QuinticEase 效果的实现算法

            // 假定动画运行的总共时间为 1 秒
            // 那么当 normalizedTime 为 0.1 时，动画运行到的位置为无该缓动效果时，0.00001秒后的位置。以此类推
            return Math.Pow(normalizedTime, 5);
        }
    }
}

CustomEasing.xaml

<navigation:Page x:Class="Silverlight30.Animation.CustomEasing" 
           xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
           xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
           xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
           xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
           mc:Ignorable="d"
           xmlns:custom="clr-namespace:Silverlight30.Animation"
           xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
           d:DesignWidth="640" d:DesignHeight="480"
           Title="CustomEasing Page">
    <Grid x:Name="LayoutRoot">
        <StackPanel>
        
            <StackPanel.Resources>
                <Storyboard x:Name="ani">
                    <DoubleAnimation 
                        Storyboard.TargetName="tt"
                        Storyboard.TargetProperty="Y"
                        From="0" 
                        To="200" 
                        Duration="00:00:03"
                    >
                        <DoubleAnimation.EasingFunction>
                            <!--使用自定义的缓动效果-->
                            <custom:MyCustomEasing EasingMode="EaseOut" />
                        </DoubleAnimation.EasingFunction>
                    </DoubleAnimation>
                </Storyboard>
            </StackPanel.Resources>

            <Button x:Name="btnShow" Content="演示" Margin="5" Click="btnShow_Click" />

            <Rectangle x:Name="rect" Fill="Blue" Width="200" Height="40" Margin="5" RenderTransformOrigin="0.5,0.5">
                <Rectangle.RenderTransform>
                    <TransformGroup>
                        <TranslateTransform x:Name="tt" X="0" Y="0" />
                    </TransformGroup>
                </Rectangle.RenderTransform>
            </Rectangle>
            
        </StackPanel>
    </Grid>
</navigation:Page>

CustomEasing.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Navigation;

namespace Silverlight30.Animation
{
    public partial class CustomEasing : Page
    {
        public CustomEasing()
        {
            InitializeComponent();
        }

        private void btnShow_Click(object sender, RoutedEventArgs e)
        {
            ani.Begin();
        }
    }
}

OK
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