void ProcessExpandAnimation()
{
if (StartTime == null)
{
return;
}
var startTime = StartTime.Value;
var elapsedTime = DateTime.Now.Subtract(startTime);
if (elapsedTime < TimeSpan.Zero)
{
return;
}
var totalDuration = Duration;
if (elapsedTime < totalDuration && this.IsVisible)
{
var normalizedTime = (Double)elapsedTime.Ticks / (Double)totalDuration.Ticks;
var easing =
(EasingFunction == null ?
normalizedTime // if there is no easing function, use linear animation.
:
EasingFunction.Ease(normalizedTime));
if (InitialSize != null && FinalSize != null)
{
var currentWidth = InitialSize.Value.Width + ((FinalSize.Value.Width - InitialSize.Value.Width) * easing);
var currentHeight = InitialSize.Value.Height + ((FinalSize.Value.Height - InitialSize.Value.Height) * easing);
CurrentSize = new Size(currentWidth, currentHeight);
}
if (InitialVerticalOffset != null && FinalVerticalOffset != null)
{
var currentVerticalOffset = InitialVerticalOffset.Value + ((FinalVerticalOffset.Value - InitialVerticalOffset.Value) * easing);
ParentScrollViewer.ScrollToVerticalOffset(currentVerticalOffset);
}
}
else
{
CurrentSize = FinalSize.Value;
if (ParentScrollViewer != null && FinalVerticalOffset != null)
{
ParentScrollViewer.ScrollToVerticalOffset(FinalVerticalOffset.Value);
InitialVerticalOffset = null;
FinalVerticalOffset = null;
}
StartTime = null;
InitialSize = null;
FinalSize = null;
}
}
