/// <summary>
/// Gets the animation time for the specified time value on the timeline. (This helper method
/// can be used for animations which start at time 0 and run with normal speed.)
/// </summary>
/// <param name="timeline">The timeline.</param>
/// <param name="time">The time on the timeline.</param>
/// <returns>
/// The animation time. (Or <see langword="null"/> if the animation is not active at
/// <paramref name="time"/>.)
/// </returns>
internal static TimeSpan?GetAnimationTime(ITimeline timeline, TimeSpan time)
{
if (time < TimeSpan.Zero)
{
// The animation has not started.
return(null);
}
TimeSpan duration = timeline.GetTotalDuration();
if (time > duration)
{
if (timeline.FillBehavior == FillBehavior.Stop)
{
// The animation has stopped.
return(null);
}
// The animation holds the final value.
Debug.Assert(timeline.FillBehavior == FillBehavior.Hold);
return(duration);
}
return(time);
}
/// <summary>
/// Gets the state of the animation for the specified time on the timeline. (This helper method
/// can be used for animations which start at time 0 and run with normal speed.)
/// </summary>
/// <param name="timeline">The timeline.</param>
/// <param name="time">The time on the timeline.</param>
/// <returns>The animation state.</returns>
internal static AnimationState GetState(ITimeline timeline, TimeSpan time)
{
if (time < TimeSpan.Zero)
{
// The animation has not started.
return(AnimationState.Delayed);
}
TimeSpan duration = timeline.GetTotalDuration();
if (time > duration)
{
if (timeline.FillBehavior == FillBehavior.Stop)
{
// The animation has stopped.
return(AnimationState.Stopped);
}
// The animation holds the last value.
Debug.Assert(timeline.FillBehavior == FillBehavior.Hold);
return(AnimationState.Filling);
}
return(AnimationState.Playing);
}
