///
override protected bool IsOffscreenCore()
{
IsOffscreenBehavior behavior = AutomationProperties.GetIsOffscreenBehavior(_owner);
switch (behavior)
{
case IsOffscreenBehavior.Onscreen:
return(false);
case IsOffscreenBehavior.Offscreen:
return(true);
case IsOffscreenBehavior.FromClip:
{
bool isOffscreen = !_owner.IsVisible;
if (!isOffscreen)
{
UIElement containingUIElement = GetContainingUIElement(_owner);
if (containingUIElement != null)
{
Rect boundingRect = UIElementAutomationPeer.CalculateVisibleBoundingRect(containingUIElement);
isOffscreen = (DoubleUtil.AreClose(boundingRect, Rect.Empty) ||
DoubleUtil.AreClose(boundingRect.Height, 0) ||
DoubleUtil.AreClose(boundingRect.Width, 0));
}
}
return(isOffscreen);
}
default:
return(!_owner.IsVisible);
}
}