/// <summary>
/// Removes the specified geometry from the tree.
/// </summary>
/// <param name="geometry">The geometry.</param>
/// <returns><c>true</c>, if the tree contains the geometry, otherwise, <c>false</c>.</returns>
protected virtual Boolean RemoveGeometry(IGeometry geometry)
{
RTreeNode leafContainer = null;
FindLeafContainer(geometry, _root, ref leafContainer);
if (leafContainer == null)
{
return(false);
}
RTreeNode nodeToRemove = leafContainer.Children.First(x => x.Geometry == geometry);
leafContainer.RemoveChild(nodeToRemove);
CondenseTree(leafContainer);
while (_root.ChildrenCount == 1 && !_root.IsLeafContainer)
{
_root = _root.Children[0];
_root.Parent = null;
_height--;
}
if (_root.ChildrenCount == 0) // occurs when the last element is removed
{
Clear();
}
return(true);
}
/// <summary>
/// Adjusts the tree after insertion, and corrects the bounding envelope of the nodes.
/// </summary>
/// <param name="node">The node where the adjustment starts.</param>
/// <param name="splitted">The second part of the node if the original node was split.</param>
/// <param name="nodeToRemove">The original node which should be removed if the original node was split.</param>
protected void AdjustTree(RTreeNode node, RTreeNode splitted = null, RTreeNode nodeToRemove = null)
{
RTreeNode n = node;
RTreeNode nn = splitted;
while (n.Parent != null)
{
RTreeNode parent = n.Parent;
parent.CorrectBounding(n.Envelope);
if (nn == null)
{
n = parent;
}
else
{
if (nodeToRemove != null)
{
parent.RemoveChild(nodeToRemove);
parent.AddChild(n);
}
if (!parent.IsFull)
{
parent.AddChild(nn);
n = parent;
nn = null;
}
else
{
parent.AddChild(nn);
SplitNode(parent, out n, out nn);
nodeToRemove = parent;
}
}
}
// create new root node if the root is split
if (nn != null)
{
_root = new RTreeNode(n.MaxChildren);
_root.AddChild(n);
_root.AddChild(nn);
_height++;
}
}
/// <summary>
/// Condenses the tree after removing a leaf node.
/// </summary>
/// <param name="leafContainerNode">The node which contained the removed node.</param>
private void CondenseTree(RTreeNode leafContainerNode)
{
Dictionary <RTreeNode, Int32> deletedNodes = new Dictionary <RTreeNode, Int32>();
RTreeNode p = leafContainerNode;
Int32 height = Height - 1;
while (p.Parent != null)
{
RTreeNode parent = p.Parent;
if (p.ChildrenCount < MinChildren)
{
parent.RemoveChild(p);
if (p.Children != null)
{
foreach (RTreeNode node in p.Children)
{
deletedNodes.Add(node, height);
}
}
}
else
{
p.CorrectBounding();
}
p = parent;
height--;
}
Int32 startHeight = Height;
foreach (KeyValuePair <RTreeNode, Int32> reInsert in deletedNodes)
{
AddNode(reInsert.Key, reInsert.Value + (Height - startHeight));
}
}