Petzold.GetMedieval.MedievalButton.OnMouseMove C# (CSharp) Method

        protected override void OnMouseMove(MouseEventArgs args)
        {
            base.OnMouseMove(args);

            Point pt = args.GetPosition(this);
            bool isReallyOverNow = (pt.X >= 0 && pt.X < ActualWidth && pt.Y >= 0 && pt.Y < ActualHeight);
            if (isReallyOverNow != isMouseReallyOver)
            {
                isMouseReallyOver = isReallyOverNow;
                InvalidateVisual();
            }
        }