title: Play DoubleAnimationUsingPath in reverse
body: <p>I have a WPF <code>Storyboard</code> (with <code>RepeatBehavior=Forever</code>) containing two <code>DoubleAnimationUsingPath</code> animations. These animations trace a circular path, which I create through adding an <code>EllipseGeometry</code>. One animation is used to control the X position, and the other animation is used to control the Y position, of another object which appears to orbit using the circular path.</p>
  
  <p>The animation always follows the path in a clockwise direction, and always starts in the middle on the right side of the circle. I need to force the animation to play in reverse (i.e. counterclockwise along the path). Ideally I'd also like to be able to control the starting position, but this isn't a necessity right now.</p>
  
  <p>The <code>AutoReverse</code> property on the animation does what I want, but obviously then it alternates between clockwise and counterclockwise - and I need the animation to loop, always in a counterclockwise direction.</p>
  
  <p>I also tried to use a <code>ScaleTransform</code> with <code>ScaleX = -1</code> in order to flip the ellipse, hoping that this would help - but it hasn't.</p>
  
  <p>Is there any way to force a <code>DoubleAnimationUsingPath</code> to follow a specific direction along the path?</p>