How can I animate an image along a circular path in WPF?

Question

I need to create a rather complex animation involving images in WPF where an image has to move along a circular path. Here is a picture of what it looks like...

Here is my xaml:

<ControlTemplate x:Key="ValveStyle" TargetType="{x:Type CheckBox}">
  <ControlTemplate.Resources>
    <PathGeometry x:Key="CirclePathGeometry" PresentationOptions:Freeze="True">
      <PathGeometry.Figures>
        <PathFigureCollection>
          <PathFigure StartPoint="340,120">
            <PathFigure.Segments>
              <PathSegmentCollection>
                <ArcSegment Size="100,50" RotationAngle="0" IsLargeArc="False" SweepDirection="CounterClockwise"
                    Point="-30,120" />
              </PathSegmentCollection>
            </PathFigure.Segments>
          </PathFigure>
        </PathFigureCollection>
      </PathGeometry.Figures>
    </PathGeometry>
  </ControlTemplate.Resources>
  <Viewbox Stretch="Uniform">
    <VisualStateManager.VisualStateGroups>
      <VisualStateGroup x:Name="CheckStates">
        <VisualStateGroup.Transitions>
          <VisualTransition GeneratedDuration="00:00:00.2000000" />
        </VisualStateGroup.Transitions>
        <VisualState x:Name="Unchecked" />
        <VisualState x:Name="Checked">
          <Storyboard>

            <!--DoubleAnimationUsingPath BeginTime="00:00:00" Storyboard.TargetName="image3" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(TranslateTransform.X)" Source="X"
                DoubleAnimationUsingPath.PathGeometry="{StaticResource CirclePathGeometry}" />
        <DoubleAnimationUsingPath BeginTime="00:00:00" Storyboard.TargetName="image3" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(TranslateTransform.Y)" Source="Y"
                DoubleAnimationUsingPath.PathGeometry="{StaticResource CirclePathGeometry}" /-->

            <MatrixAnimationUsingPath Storyboard.TargetName="Image3MatrixTransform" Storyboard.TargetProperty="Matrix"
                MatrixAnimationUsingPath.PathGeometry="{StaticResource CirclePathGeometry}" />
            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000"
                Storyboard.TargetName="image1"
                Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[2].(RotateTransform.Angle)">
              <SplineDoubleKeyFrame KeyTime="00:00:00" Value="-90" />
            </DoubleAnimationUsingKeyFrames>
            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000"
                Storyboard.TargetName="image2"
                Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[2].(RotateTransform.Angle)">
              <SplineDoubleKeyFrame KeyTime="00:00:00" Value="-90" />
            </DoubleAnimationUsingKeyFrames>
            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000"
                Storyboard.TargetName="image"
                Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[2].(RotateTransform.Angle)">
              <SplineDoubleKeyFrame KeyTime="00:00:00" Value="-90" />
            </DoubleAnimationUsingKeyFrames>
          </Storyboard>
        </VisualState>
      </VisualStateGroup>
    </VisualStateManager.VisualStateGroups>
    <VisualStateManager.CustomVisualStateManager>
      <ic:ExtendedVisualStateManager />
    </VisualStateManager.CustomVisualStateManager>
    <Canvas Width="685" Height="527">
      <Image Source="/VT;component/Images/Valve121.1-Base.png" Stretch="Fill" />
      <Image x:Name="image" Source="/VT;component/Images/Valve121.1-LeftBar1.png" Stretch="Fill"
          Canvas.Left="61.991" Canvas.Top="49.329" RenderTransformOrigin="0.286,0.5428">
        <Image.RenderTransform>
          <TransformGroup>
            <ScaleTransform />
            <SkewTransform />
            <RotateTransform />
            <TranslateTransform />
          </TransformGroup>
        </Image.RenderTransform>
      </Image>
      <Image x:Name="image2" Source="/VT;component/Images/Valve121.1-RightBar.png" Stretch="Fill"
          Canvas.Left="436.491" Canvas.Top="49.388" RenderTransformOrigin="0.249,0.756">
        <Image.RenderTransform>
          <TransformGroup>
            <ScaleTransform />
            <SkewTransform />
            <RotateTransform />
            <TranslateTransform />
          </TransformGroup>
        </Image.RenderTransform>
      </Image>
      <Image x:Name="image3" Source="/VT;component/Images/Valve121.1-HzBar.png" Stretch="Fill"
          Canvas.Left="277.491" Canvas.Top="58.345">
        <Image.RenderTransform>
          <MatrixTransform x:Name="Image3MatrixTransform" />
        </Image.RenderTransform>
      </Image>
      <Image Source="/VT;component/Images/Valve121.1-Overlay.png" Stretch="Fill" />
      <Image x:Name="image1" Source="/VT;component/Images/Valve121.1-LeftBar2.png" Stretch="Fill"
          Canvas.Left="129.824" Canvas.Top="24.661" RenderTransformOrigin="0.5,0.5">
        <Image.RenderTransform>
          <TransformGroup>
            <ScaleTransform />
            <SkewTransform />
            <RotateTransform />
            <TranslateTransform />
          </TransformGroup>
        </Image.RenderTransform>
      </Image>
      <Path Stroke="Blue" StrokeThickness="10" RenderTransformOrigin="-0.333,-0.227">
        <Path.Data>
          <PathGeometry>
            <PathFigureCollection>
              <PathFigure StartPoint="340,120">
                <PathFigure.Segments>
                  <PathSegmentCollection>
                    <ArcSegment Size="100,50" RotationAngle="0" IsLargeArc="False" SweepDirection="CounterClockwise"
                        Point="-30,120" />
                  </PathSegmentCollection>
                </PathFigure.Segments>
              </PathFigure>
            </PathFigureCollection>
          </PathGeometry>
        </Path.Data>
      </Path>
    </Canvas>
  </Viewbox>
</ControlTemplate>

I'm facing several problems:

• The image (image3) doesn't seem to move correctly along the path I have set, so I guess I made a mistake there...
• The animation of the image (image3) starts after all other animation are done. I would like that all animations start at the same time.

I've tried both DoubleAnimationUsingPath and MatrixAnimationUsingPath but none of them worked the way I want. Is it even possible to mix Key Frames animation and Path animations ?

Is it possible to do such an animation in WPF? If so, how can I achieve this?

Answer 1

Define your MainWindow (or Page) class as follows:

<Window x:Class="TestCustomTab.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300">
    <Window.Resources>
        <PathGeometry x:Key="path" Figures="M 0,50 A 50,50 0 1 1 100,50 " />         
        <Storyboard x:Key="ellipseSB">
            <DoubleAnimationUsingPath Storyboard.TargetName="ellipse"
Storyboard.TargetProperty="(Canvas.Left)"
PathGeometry="{StaticResource path}"
Duration="0:0:5" RepeatBehavior="Forever" AutoReverse="True" Source="X" />
            <DoubleAnimationUsingPath Storyboard.TargetName="ellipse"
Storyboard.TargetProperty="(Canvas.Top)"
PathGeometry="{StaticResource path}"
Duration="0:0:5" RepeatBehavior="Forever" AutoReverse="True" Source="Y" />
        </Storyboard>        
    </Window.Resources>
    <Grid x:Name="grid">
        <Canvas>
            <Ellipse x:Name="ellipse" Width="10" Height="10" Stroke="Black" Fill="Black" RenderTransformOrigin="0.5,0.5" />            
            <Path Stroke="Red" StrokeThickness="1" Canvas.Left="5" Canvas.Top="5" Data="{StaticResource path}"/>
        </Canvas>        
        <Button VerticalAlignment="Bottom" Content="Start" Click="Button_Click"/>
    </Grid>
</Window>

Then in codebehind define Button_Click event handler:

private void Button_Click(object sender, RoutedEventArgs e)
        {
            var sb = FindResource("ellipseSB") as Storyboard;
            if (sb != null) sb.Begin();
        }

It will animate 5*5 ellipse exactly by the defined arc segment which is a half of a circle.

Hope this helps.