WPF：Animation动画--PathAnimation路径动画效果

PahtAnimation路径动画：

PointAnimationUsingPath使用路径坐标动画效果

关注点：
1 PointAnimationUsingPath 类：对两个或更多个目标值之间的 Point 属性值进行动画处理，通过使用 PathGeometry 指定这些目标值。此动画可用于沿着路径移动可视对象。

设置一个线性形状Path及一个几何圆的形状Path

<Canvas HorizontalAlignment="Left" Width="340" Height="240" >
      
  <!-- This Path is only to show the path that the animated object will follow. -->
  <Path VerticalAlignment="Top" Margin="15,15,15,15" 
    Data="M 10,100 C 35,0 135,0 160,100 180,190 285,200 310,100"
    Stroke="Black" StrokeThickness="2"
    Stretch="None" />
  
  <Path Fill="Blue" Margin="15,15,15,15">
    <Path.Data>
    
      <!-- Describes an ellipse. -->
      <EllipseGeometry x:Name="MyAnimatedEllipseGeometry"
        Center="10,100" RadiusX="15" RadiusY="15" />
    </Path.Data>
  </Path>
</Canvas>

针对几何圆使用路径坐标动画PointAnimationUsingPath，此处需PointAnimationUsingPath.PathGeometry确定路径路线

<!-- Create a button to restart the animation. -->
<Button Width="80" HorizontalAlignment="Left" >Start Animation

  <!-- Trigger and StoryBoard to initiate the animation when the button is clicked. -->
  <Button.Triggers>
    <EventTrigger RoutedEvent="Button.Click">
      <BeginStoryboard Name="MyBeginStoryboard">
        <Storyboard>
          
          <!-- Animates the ellipse along the path. -->
          <PointAnimationUsingPath
            Storyboard.TargetName="MyAnimatedEllipseGeometry"
            Storyboard.TargetProperty="Center"
            Duration="0:0:5" 
            RepeatBehavior="Forever" AutoReverse="True" >
            <PointAnimationUsingPath.PathGeometry>
              <PathGeometry Figures="M 10,100 C 35,0 135,0 160,100 180,190 285,200 310,100" />
            </PointAnimationUsingPath.PathGeometry>
          </PointAnimationUsingPath>
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Button.Triggers>
</Button>      
</StackPanel>

DoubleAnimationUsingPathExample使用路径浮点值动画

同理针对矩形使用路径浮点值动画，不过动画对象为矩形的平移转换器的X、Y值。

<!-- Trigger and StoryBoard to initiate the animation when the button is clicked. -->
  <Button.Triggers>
    <EventTrigger RoutedEvent="Button.Click">
      <BeginStoryboard Name="MyBeginStoryboard">
        <Storyboard>

          <!-- Animates the rectangle horizotally along the path. -->
          <DoubleAnimationUsingPath
            Storyboard.TargetName="MyAnimatedTransform"
            Storyboard.TargetProperty="X"
            Source="X" 
            Duration="0:0:5" 
            RepeatBehavior="Forever" AutoReverse="True" >
            <DoubleAnimationUsingPath.PathGeometry>
              <PathGeometry Figures="M 10,100 C 35,0 135,0 160,100 180,190 285,200 310,100" />
            </DoubleAnimationUsingPath.PathGeometry>
          </DoubleAnimationUsingPath>

          <!-- Animates the rectangle vertically along the path. -->
          <DoubleAnimationUsingPath
            Storyboard.TargetName="MyAnimatedTransform"
            Storyboard.TargetProperty="Y"
            Source="Y" 
            Duration="0:0:5" 
            RepeatBehavior="Forever" AutoReverse="True" >
            <DoubleAnimationUsingPath.PathGeometry>
              <PathGeometry Figures="M 10,100 C 35,0 135,0 160,100 180,190 285,200 310,100" />
            </DoubleAnimationUsingPath.PathGeometry>
          </DoubleAnimationUsingPath>
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Button.Triggers>

RotateAnimationUsingPathExample使用路径的旋转动画

要使矩形沿着路径运行，同时矩形的旋转角度跟随路线切线。

设计有矩形形状，且实例化有矩形的旋转及平移转换器。

<!-- This geometry renders the rectangle that is animated across the screen. -->
<Path Fill="Blue" Margin="0,0,15,15">
  <Path.Data>
    <RectangleGeometry  x:Name="MyAnimatedRectGeometry" Rect="0,0 30 30" >
      <RectangleGeometry.Transform>
        <TransformGroup>
          <RotateTransform x:Name="MyRotateTransform" Angle="0" CenterX="15" CenterY="15" />
          <TranslateTransform x:Name="MyTranslateTransform" X="10" Y="100" />
        </TransformGroup>
      </RectangleGeometry.Transform>
    </RectangleGeometry>
  </Path.Data>
</Path>

针对矩形的旋转角度值DoubleAnimationUsingPath及平移转换器的X、YDoubleAnimationUsingPath动画：

<!-- Trigger and StoryBoard to initiate the animation when the button is clicked. -->
  <Button.Triggers>
    <EventTrigger RoutedEvent="Button.Click">
      <BeginStoryboard Name="MyBeginStoryboard">
        <Storyboard>

          <!-- Animates the angle along the path. -->
          <DoubleAnimationUsingPath
            Storyboard.TargetName="MyRotateTransform"
            Storyboard.TargetProperty="Angle"
            Source="Angle" 
            Duration="0:0:5" 
            RepeatBehavior="Forever" AutoReverse="True" >
            <DoubleAnimationUsingPath.PathGeometry>
              <PathGeometry Figures="M 10,100 C 35,0 135,0 160,100 180,190 285,200 310,100" />
            </DoubleAnimationUsingPath.PathGeometry>
          </DoubleAnimationUsingPath>

          <!-- Animates the rectangle horizotally along the path. -->
          <DoubleAnimationUsingPath
            Storyboard.TargetName="MyTranslateTransform"
            Storyboard.TargetProperty="X"
            Source="X" 
            Duration="0:0:5" 
            RepeatBehavior="Forever" AutoReverse="True" >
            <DoubleAnimationUsingPath.PathGeometry>
              <PathGeometry Figures="M 10,100 C 35,0 135,0 160,100 180,190 285,200 310,100" />
            </DoubleAnimationUsingPath.PathGeometry>
          </DoubleAnimationUsingPath>

          <!-- Animates the rectangle vertically along the path. -->
          <DoubleAnimationUsingPath
            Storyboard.TargetName="MyTranslateTransform"
            Storyboard.TargetProperty="Y"
            Source="Y" 
            Duration="0:0:5" 
            RepeatBehavior="Forever" AutoReverse="True" >
            <DoubleAnimationUsingPath.PathGeometry>
              <PathGeometry Figures="M 10,100 C 35,0 135,0 160,100 180,190 285,200 310,100" />
            </DoubleAnimationUsingPath.PathGeometry>
          </DoubleAnimationUsingPath>
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Button.Triggers>

MatrixAnimationUsingPathExample使用路径的Matrix动画效果

1、 MatrixAnimationUsingPath.DoesRotateWithTangent 属性：获取或设置一个值，该值指示对象是否沿路径的切线旋转。

图中并未设置Matrix动画值，默认为沿路径平移
当DoesRotateWithTangent=”True“时，矩形方框在平移时，会沿路径的线的角度旋转。

<!-- This button starts an animation that follows the tangent
of the path because DoesRotateWithTangent is set to "True".-->
<Button Width="300" HorizontalAlignment="Left" >
  Start Animation with DoesRotateWithTangent="True"

  <!-- Trigger and StoryBoard to initiate the animation when the button is clicked. -->
  <Button.Triggers>
    <EventTrigger RoutedEvent="Button.Click">
      <BeginStoryboard>
        <Storyboard>

          <!-- Animates the button along the path following the tangent of the path. -->
          <MatrixAnimationUsingPath
            Storyboard.TargetName="myMatrixTransform"
            Storyboard.TargetProperty="Matrix"
            DoesRotateWithTangent="True" 
            Duration="0:0:5" 
            RepeatBehavior="Forever" AutoReverse="True" >
            <MatrixAnimationUsingPath.PathGeometry>
              <PathGeometry Figures="M 10,100 C 35,0 135,0 160,100 180,190 285,200 310,100" />
            </MatrixAnimationUsingPath.PathGeometry>
          </MatrixAnimationUsingPath>
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Button.Triggers>
</Button>