/// <summary>
/// Returns the subquad containing the envelope.
/// Creates the subquad if
/// it does not already exist.
/// </summary>
/// <param name="searchEnv"></param>
public virtual Node GetNode(IEnvelope searchEnv)
{
int subnodeIndex = GetSubnodeIndex(searchEnv, _centre);
// if subquadIndex is -1 searchEnv is not contained in a subquad
if (subnodeIndex != -1)
{
// create the quad if it does not exist
Node node = GetSubnode(subnodeIndex);
// recursively search the found/created quad
return(node.GetNode(searchEnv));
}
return(this);
}
/// <summary>
/// Insert an item which is known to be contained in the tree rooted at
/// the given QuadNode root. Lower levels of the tree will be created
/// if necessary to hold the item.
/// </summary>
private static void InsertContained(Node tree, IEnvelope itemEnv, object item)
{
Assert.IsTrue(tree.Envelope.Contains(itemEnv));
/*
* Do NOT create a new quad for zero-area envelopes - this would lead
* to infinite recursion. Instead, use a heuristic of simply returning
* the smallest existing quad containing the query
*/
bool isZeroX = IntervalSize.IsZeroWidth(itemEnv.Minimum.X, itemEnv.Maximum.X);
bool isZeroY = IntervalSize.IsZeroWidth(itemEnv.Minimum.X, itemEnv.Maximum.X);
NodeBase node;
if (isZeroX || isZeroY)
{
node = tree.Find(itemEnv);
}
else
{
node = tree.GetNode(itemEnv);
}
node.Add(item);
}
/// <summary>
/// Insert an item which is known to be contained in the tree rooted at
/// the given QuadNode root. Lower levels of the tree will be created
/// if necessary to hold the item.
/// </summary>
private static void InsertContained(Node tree, IEnvelope itemEnv, object item)
{
Assert.IsTrue(tree.Envelope.Contains(itemEnv));
/*
* Do NOT create a new quad for zero-area envelopes - this would lead
* to infinite recursion. Instead, use a heuristic of simply returning
* the smallest existing quad containing the query
*/
bool isZeroX = IntervalSize.IsZeroWidth(itemEnv.Minimum.X, itemEnv.Maximum.X);
bool isZeroY = IntervalSize.IsZeroWidth(itemEnv.Minimum.X, itemEnv.Maximum.X);
NodeBase node;
if (isZeroX || isZeroY)
node = tree.Find(itemEnv);
else node = tree.GetNode(itemEnv);
node.Add(item);
}