/// <summary>
/// Core update routine.
/// </summary>
/// <param name="context">The context that holds information about the animation.</param>
protected override void UpdateAnimationOverride(AnimationContext context)
{
context.EnsureDefaultTransforms();
ScaleTransform transform = context.Target.GetScaleTransform();
double fromY = this.StartScaleY.HasValue ? this.StartScaleY.Value : transform.ScaleY;
double toY = this.EndScaleY.HasValue ? this.EndScaleY.Value : transform.ScaleY;
double duration = this.Duration.TimeSpan.TotalSeconds;
context.ScaleY(0, fromY, duration, toY);
base.UpdateAnimationOverride(context);
}