如何：使动画加速或减速

更新：2007 年 11 月

此示例演示如何使动画随着时间的推移而加速和减速。在下面的示例中，使用不同的 AccelerationRatio 和 DecelerationRatio 动画设置对多个矩形进行动画处理。

示例

<!-- This example shows how to use the AccelerationRatio and 
     DecelerationRatio properties of timelines
     to make animations speed up or slow down as they progress. -->
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation" 
  xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:SampleControls="SampleControls"
  WindowTitle="Acceleration and Deceleration Example">
  <StackPanel Margin="20">

    <Rectangle Name="nonAcceleratedOrDeceleratedRectangle" Fill="#9933FF" 
      Width="10" Height="20" HorizontalAlignment="Left" />

    <Rectangle Name="acceleratedRectangle" Fill="#3333FF" 
      Width="10" Height="20" HorizontalAlignment="Left" />

    <Rectangle Name="deceleratedRectangle" Fill="#33FF66" 
      Width="10" Height="20" HorizontalAlignment="Left" />

    <Rectangle Name="acceleratedAndDeceleratedRectangle" Fill="#CCFF33" 
      Width="10" Height="20" HorizontalAlignment="Left" />

    <!-- Create a button to start the animations. -->
    <Button Margin="0,30,0,0" HorizontalAlignment="Left"
      Content="Start Animations">
      <Button.Triggers>
        <EventTrigger RoutedEvent="Button.Click">
          <BeginStoryboard>
            <Storyboard>

              <!-- Creates an animation without acceleration or deceleration for comparison. -->
              <DoubleAnimation         
                Storyboard.TargetName="nonAcceleratedOrDeceleratedRectangle" 
                Storyboard.TargetProperty="(Rectangle.Width)"
                Duration="0:0:10" From="20" To="400" />              

              <!-- Creates an animation that accelerates through 40% of its duration. -->
              <DoubleAnimation 
                Storyboard.TargetName="acceleratedRectangle" 
                Storyboard.TargetProperty="(Rectangle.Width)"
                AccelerationRatio="0.4" Duration="0:0:10" From="20" To="400" />

              <!-- Creates an animation that decelerates through 60% of its duration. -->
              <DoubleAnimation 
                Storyboard.TargetName="deceleratedRectangle" 
                Storyboard.TargetProperty="(Rectangle.Width)"
                DecelerationRatio="0.6" Duration="0:0:10" From="20" To="400" />

              <!-- Creates an animation that accelerates through 40% of its duration and
                   decelerates through the 60% of its duration. -->
              <DoubleAnimation 
                Storyboard.TargetName="acceleratedAndDeceleratedRectangle" 
                Storyboard.TargetProperty="(Rectangle.Width)"
                AccelerationRatio="0.4" DecelerationRatio="0.6" Duration="0:0:10" From="20" To="400" />      
            </Storyboard>  
          </BeginStoryboard>
        </EventTrigger>      
      </Button.Triggers>         
    </Button>
  </StackPanel> 
</Page>

此示例省略了代码。有关完整的代码，请参见动画计时行为的示例。