/*
* Copyright (c) 2016 Vivid Solutions.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
*
* http://www.eclipse.org/org/documents/edl-v10.php.
*/
package org.locationtech.jts.index.quadtree;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.Envelope;
import org.locationtech.jts.util.Assert;
/**
* QuadRoot is the root of a single Quadtree. It is centred at the origin,
* and does not have a defined extent.
*
* @version 1.7
*/
public class Root
extends NodeBase
{
// the singleton root quad is centred at the origin.
private static final Coordinate origin = new Coordinate(0.0, 0.0);
public Root()
{
}
/**
* Insert an item into the quadtree this is the root of.
*/
public void insert(Envelope itemEnv, Object item)
{
int index = getSubnodeIndex(itemEnv, origin.x, origin.y);
// if index is -1, itemEnv must cross the X or Y axis.
if (index == -1) {
add(item);
return;
}
/**
* the item must be contained in one quadrant, so insert it into the
* tree for that quadrant (which may not yet exist)
*/
Node node = subnode[index];
/**
* If the subquad doesn't exist or this item is not contained in it,
* have to expand the tree upward to contain the item.
*/
if (node == null || ! node.getEnvelope().contains(itemEnv)) {
Node largerNode = Node.createExpanded(node, itemEnv);
subnode[index] = largerNode;
}
/**
* At this point we have a subquad which exists and must contain
* contains the env for the item. Insert the item into the tree.
*/
insertContained(subnode[index], itemEnv, item);
//System.out.println("depth = " + root.depth() + " size = " + root.size());
//System.out.println(" size = " + size());
}
/**
* 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.
*/
private void insertContained(Node tree, Envelope itemEnv, Object item)
{
Assert.isTrue(tree.getEnvelope().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
*/
boolean isZeroX = IntervalSize.isZeroWidth(itemEnv.getMinX(), itemEnv.getMaxX());
boolean isZeroY = IntervalSize.isZeroWidth(itemEnv.getMinY(), itemEnv.getMaxY());
NodeBase node;
if (isZeroX || isZeroY)
node = tree.find(itemEnv);
else
node = tree.getNode(itemEnv);
node.add(item);
}
protected boolean isSearchMatch(Envelope searchEnv)
{
return true;
}
}