protected void NotifyDisplayedArea()
{
if (m_Page == null)
{
return;
}
RectangleF displayed = ViewableArea();
if (displayed.ApproxEqual(new RectangleF(new PointF(0, 0), m_Page.Size)))
{
displayed = RectangleF.Empty; // this makes it easier for the outside world to know that the entire page is displayed
}
DisplayedAreaChanged?.Invoke(displayed);
}