问如何将wpf中的动画缩放到窗口的大小

EN

<Window x:Class="TestPointAlongPath.MainWindow"
        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"
        xmlns:PresentationOptions="http://schemas.microsoft.com/winfx/2006/xaml/presentation/options" 
        mc:Ignorable="PresentationOptions"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Path Data="M1,200 L275,1 L345,200" Margin="15,15,15,15" 
                        Stroke="#BF708090" StrokeThickness="3" />

        <Path Fill="Blue" Margin="15,15,15,15" >
            <Path.Data>

                <!-- The EllipseGemetry specifies the shape and position of the Ellipse. The
            Center property is animated, causing the Ellipse to animate across the screen-->
                <EllipseGeometry x:Name="MyAnimatedEllipseGeometry"
                Center="10,100" RadiusX="15" RadiusY="15"/>
            </Path.Data>
            <Path.Triggers>
                <EventTrigger RoutedEvent="Path.Loaded">
                    <BeginStoryboard Name="MyBeginStoryboard">
                        <Storyboard>

                            <!-- Animates the ellipse along the path. -->
                            <PointAnimationUsingPath
                    Storyboard.TargetName="MyAnimatedEllipseGeometry"
                    Storyboard.TargetProperty="Center"
                    Duration="0:0:7.5" 
                    RepeatBehavior="Forever" >
                                <PointAnimationUsingPath.PathGeometry>
                                    <PathGeometry 
                        Figures="M1,200 L275,1 L345,200"
                        PresentationOptions:Freeze="True">
                                        <PathGeometry.Transform>
                                            <ScaleTransform ScaleX="{Binding ActualWidth, RelativeSource={RelativeSource AncestorType=Grid}}"
                                                            ScaleY="{Binding ActualHeight, RelativeSource={RelativeSource AncestorType=Grid}}"/>
                                        </PathGeometry.Transform>
                                    </PathGeometry>
                                </PointAnimationUsingPath.PathGeometry>
                            </PointAnimationUsingPath>
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger>
            </Path.Triggers>
        </Path>
    </Grid>
</Window>