/// <summary>
/// Includes a spatial indexing node in these statistics
/// </summary>
/// <param name="n">The node to include</param>
internal void Add(Node n)
{
m_NumNode++;
if (n is RectangleIndex)
m_NumParentNode++;
m_MaxItemPerNode = Math.Max(m_MaxItemPerNode, n.ItemCount);
m_NumItem += n.ItemCount;
if (n.ItemCount==0)
m_NumEmptyNode++;
m_MinSize = Math.Min(m_MinSize, n.Window.Width);
m_MinSize = Math.Min(m_MinSize, n.Window.Height);
}
/// <summary>
/// Creates a child node, remembering it as as child of this node.
/// </summary>
/// <param name="childWindow">The spatial extent of the new child</param>
/// <returns>The created node is either an instance of <see cref="Node"/> (for
/// child nodes that are quite small), or a new (smaller) instance of
/// this class.</returns>
Node CreateChild(Extent childWindow)
{
// If the child is quite small, make it a leaf node (the number here
// means we effectively ignore the 3 low-order bytes in X & Y, meaning
// that a leaf node will cover approx 16x16 metres on the ground).
Node child;
if (childWindow.Width < SMALL && childWindow.Height < SMALL)
child = new Node(childWindow);
else
child = new RectangleIndex(childWindow);
if (m_Children==null)
m_Children = new List<Node>(1);
m_Children.Add(child);
return child;
}