Creating countdown circle with ArcSegment in WPF

Question

I am trying to do a countdown circle. But I just cannot get it working. What I can do is to create a filling circle, but not one for countdown. Hopefully code will be clear. What I am trying to do is exactly what reverse animation does ( commented in code )

<UserControl.Triggers>
    <EventTrigger RoutedEvent="Page.Loaded">
        <BeginStoryboard>
            <Storyboard >
                <!--RepeatBehavior="Forever"
                AutoReverse="True" >-->
                <PointAnimationUsingPath
                        Storyboard.TargetName="arc"
                        Storyboard.TargetProperty="Point"
                        Duration="0:0:5">
                    <PointAnimationUsingPath.PathGeometry>
                        <PathGeometry>
                            <PathFigure StartPoint="200 100">
                                <ArcSegment Size="100 100" Point="200 300" SweepDirection="Clockwise"  />
                                <ArcSegment Size="100 100" Point="200 100" SweepDirection="Clockwise" />
                            </PathFigure>
                        </PathGeometry>
                    </PointAnimationUsingPath.PathGeometry>
                </PointAnimationUsingPath>

                <BooleanAnimationUsingKeyFrames
                        Storyboard.TargetName="arc"
                        Storyboard.TargetProperty="IsLargeArc">
                    <DiscreteBooleanKeyFrame KeyTime="0:0:2.5" Value="True" />
                    <DiscreteBooleanKeyFrame KeyTime="0:0:5" Value="False" />
                </BooleanAnimationUsingKeyFrames>
            </Storyboard>
        </BeginStoryboard>
    </EventTrigger>
</UserControl.Triggers>

<Path Stroke="Blue" StrokeThickness="3" Fill="Transparent">
    <Path.Data>
        <PathGeometry>
            <PathFigure StartPoint="200 100" IsClosed="False">
                <ArcSegment x:Name="arc" Size="100 100" SweepDirection="Clockwise" />
            </PathFigure>
        </PathGeometry>
    </Path.Data>
</Path>

Answer 1

我终于设法只使用一个ArcSegment动画点来解决它，该动画点的端点与起始点的偏差为.01，并且为IsLargeArc改变了离散布尔动画的时间，尽管我体验到ArcSegment有时在不更改代码的情况下表现有所不同。