ARCed.UI.DockPanel.SplitterDragHandler.GetMovingOffset C# (CSharp) Method

            private int GetMovingOffset(Point ptMouse)
            {
                Rectangle rect = this.GetSplitterOutlineBounds(ptMouse);
                if (this.DragSource.IsVertical)
                    return rect.X - this.RectSplitter.X;
                else
                    return rect.Y - this.RectSplitter.Y;
            }