/// <summary>
///
/// </summary>
/// <param name="node"></param>
/// <param name="addEnv"></param>
/// <returns></returns>
public static Node CreateExpanded(Node node, IEnvelope addEnv)
{
Envelope expandEnv = new Envelope(addEnv);
if (node != null)
expandEnv.ExpandToInclude(node._env);
Node largerNode = CreateNode(expandEnv);
if (node != null)
largerNode.InsertNode(node);
return largerNode;
}
/// <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>
///
/// </summary>
/// <param name="index"></param>
/// <returns></returns>
private Node CreateSubnode(int index)
{
// create a new subquad in the appropriate quadrant
double minx = 0.0;
double maxx = 0.0;
double miny = 0.0;
double maxy = 0.0;
switch (index)
{
case 0:
minx = _env.Minimum.X;
maxx = _centre.X;
miny = _env.Minimum.Y;
maxy = _centre.Y;
break;
case 1:
minx = _centre.X;
maxx = _env.Maximum.X;
miny = _env.Minimum.Y;
maxy = _centre.Y;
break;
case 2:
minx = _env.Minimum.X;
maxx = _centre.X;
miny = _centre.Y;
maxy = _env.Maximum.Y;
break;
case 3:
minx = _centre.X;
maxx = _env.Maximum.X;
miny = _centre.Y;
maxy = _env.Maximum.Y;
break;
default:
break;
}
Envelope sqEnv = new Envelope(minx, maxx, miny, maxy);
Node node = new Node(sqEnv, _level - 1);
return node;
}
/// <summary>
///
/// </summary>
/// <param name="env"></param>
/// <returns></returns>
public static Node CreateNode(IEnvelope env)
{
Key key = new Key(env);
Node node = new Node(key.Envelope, key.Level);
return node;
}
/// <summary>
///
/// </summary>
/// <param name="node"></param>
public virtual void InsertNode(Node node)
{
Assert.IsTrue(_env == null || _env.Contains(node.Envelope));
int index = GetSubnodeIndex(node._env, _centre);
if (node._level == _level - 1)
Nodes[index] = node;
else
{
// the quad is not a direct child, so make a new child quad to contain it
// and recursively insert the quad
Node childNode = CreateSubnode(index);
childNode.InsertNode(node);
Nodes[index] = childNode;
}
}