gojs/extensionsJSM/Quadtree.js

/*
*  Copyright (C) 1998-2021 by Northwoods Software Corporation. All Rights Reserved.
*/
import * as go from '../release/go-module.js';
/**
 * @hidden @internal
 */
class QuadNode {
    constructor(bounds, parent, level) {
        this.objects = [];
        this.treeObjects = [];
        this.totalObjects = 0; // total in this node + in all children (recursively)
        this.nodes = [null, null, null, null];
        this.bounds = bounds;
        this.parent = parent;
        this.level = level;
    }
    split() {
        const w2 = this.bounds.width / 2;
        const h2 = this.bounds.height / 2;
        const x = this.bounds.x;
        const y = this.bounds.y;
        this.nodes[0] = new QuadNode(new go.Rect(x + w2, y, w2, h2), this, this.level + 1);
        this.nodes[1] = new QuadNode(new go.Rect(x, y, w2, h2), this, this.level + 1);
        this.nodes[2] = new QuadNode(new go.Rect(x, y + h2, w2, h2), this, this.level + 1);
        this.nodes[3] = new QuadNode(new go.Rect(x + w2, y + h2, w2, h2), this, this.level + 1);
    }
    clear() {
        this.treeObjects = [];
        this.objects = [];
        this.totalObjects = 0;
        for (let i = 0; i < this.nodes.length; i++) {
            const n = this.nodes[i];
            if (n !== null) {
                n.clear();
                this.nodes[i] = null;
            }
        }
    }
}
/**
 * @internal @hidden
 * Object to be contained by the {@link Quadtree} class. This object needs
 * to have rectangular bounds (described by an {@link Rect} object), as well
 * as something (of any type) associated with it.
 */
class QuadObj {
    constructor(bounds, obj) {
        this.bounds = bounds;
        this.obj = obj;
    }
}
/**
 * Implementation of the quadtree data structure using the {@link Rect} class.
 * Each Quadtree has defined bounds found at {@link #bounds}, an array
 * of member rectangles, and an array of child nodes
 * (Quadtrees themselves). If the Quadtree has no
 * children, the nodes array will have four nulls. To construct a Quadtree, you
 * can call its constructor with no arguments. Then, to insert a rectangle, call
 * {@link #add}. This tree supports adding points (rectangles with 0
 * width and height), segments (rectangles with either 0 width or 0 height), and
 * rectangles with nonzero widths and heights.
 *
 * Quadtrees can be used to calculate intersections extremely quickly between a
 * given rectangle and all of the rectangles in the quadtree. Use of this data
 * structure prevents having to do precise intersection calculations for every
 * rectangle in the tree. To calculate all of the rectangular intersections for
 * a given rectangle, use {@link #intersecting}.
 *
 * Other common operations are detailed below.
 * @category Layout Extension
 */
export class Quadtree {
    /**
     * In most cases, simply calling this constructor with no arguments will produce the desired behaviour.
     * @constructor
     * @param {number=} nodeCapacity The node capacity of this quadtree. This is the number of objects a node can contain before it splits. Defaults to 1.
     * @param {number=} maxLevel The maximum depth the Quadtree will allow before it will no longer split. Defaults to Infinity (no maximum depth).
     * @param {Rect=} bounds The bounding box surrounding the entire Quadtree. If the bounds are unset or a node is inserted outside of the bounds, the tree will automatically grow.
     */
    constructor(nodeCapacity, maxLevel, bounds) {
        /** @hidden @internal */ this._nodeCapacity = 1;
        /** @hidden @internal */ this._maxLevels = Infinity;
        /** @hidden @internal */ this._treeObjectMap = new go.Map();
        // we can avoid unnecessary work when adding objects if there are no objects with 0 width or height.
        // Note that after being set to true, these flags are not ever set again to false, even if all objects
        // with zero width/height are removed (assumption was made that this should almost never matter)
        /** @hidden @internal */ this._hasZeroWidthObject = false;
        /** @hidden @internal */ this._hasZeroHeightObject = false;
        if (nodeCapacity) {
            this._nodeCapacity = nodeCapacity;
        }
        if (maxLevel) {
            this._maxLevels = maxLevel;
        }
        if (bounds === undefined) {
            bounds = new go.Rect();
        }
        this._root = new QuadNode(bounds, null, 0);
    }
    /**
     * Gets the node capacity of this quadtree. This is the number of objects a node can contain before it splits.
     */
    get nodeCapacity() { return this._nodeCapacity; }
    /**
     * Gets the maximum depth the Quadtree will allow before it will no longer split..
     */
    get maxLevels() { return this._maxLevels; }
    /**
     * Gets the boundaries of the node. All nodes should be square.
     */
    get bounds() { return this._root.bounds; }
    /**
     * Gets the root node of the tree
     */
    get root() { return this._root; }
    /**
     * Clears the Quadtree, removing all objects and children nodes. Keeps the current bounds of the root node.
     * @this {Quadtree}
     * @return {void}
     */
    clear() {
        this._root.clear();
        this._treeObjectMap.clear();
    }
    /**
     * @hidden @internal
     * Returns a list of possible quadrants that the given rect could be in
     * @this {Quadtree}
     * @param {Rect} rect the rectangle to test
     * @return {Array<number>}
     */
    _getQuadrants(rect, node) {
        const quadrants = [];
        const horizontalMidpoint = node.bounds.x + (node.bounds.width / 2);
        const verticalMidpoint = node.bounds.y + (node.bounds.height / 2);
        const topQuadrant = rect.y <= verticalMidpoint;
        const bottomQuadrant = rect.y + rect.height >= verticalMidpoint;
        if (rect.x <= horizontalMidpoint) {
            if (topQuadrant) {
                quadrants.push(1);
            }
            if (bottomQuadrant) {
                quadrants.push(2);
            }
        }
        if (rect.x + rect.width >= horizontalMidpoint) {
            if (topQuadrant) {
                quadrants.push(0);
            }
            if (bottomQuadrant) {
                quadrants.push(3);
            }
        }
        return quadrants;
    }
    /**
     * @hidden @internal
     * Determine which node the rect belongs to. -1 means rect
     * cannot completely fit within a child node and is part of
     * the parent node. This function avoids some additional
     * calculations by assuming that the rect is contained entirely
     * within the parent node's bounds.
     * @this {Quadtree}
     * @param {Rect} rect the rect to test
     * @return {number}
     */
    _getIndex(rect, node) {
        let index = -1;
        if (node.bounds === undefined) { // the quadtree is empty
            return index;
        }
        const horizontalMidpoint = node.bounds.x + (node.bounds.width / 2);
        const verticalMidpoint = node.bounds.y + (node.bounds.height / 2);
        const topQuadrant = rect.y <= verticalMidpoint && rect.y + rect.height <= verticalMidpoint;
        const bottomQuadrant = rect.y >= verticalMidpoint;
        if (rect.x + rect.width <= horizontalMidpoint) {
            if (topQuadrant) {
                index = 1;
            }
            else if (bottomQuadrant) {
                index = 2;
            }
        }
        else if (rect.x >= horizontalMidpoint) {
            if (topQuadrant) {
                index = 0;
            }
            else if (bottomQuadrant) {
                index = 3;
            }
        }
        return index;
    }
    /**
     * Insert the object into the quadtree. If the node
     * exceeds the capacity, it will split and add all
     * objects to their corresponding nodes. If the object is
     * outside the bounds of the tree's root node, the tree
     * will grow to accomodate it. Possibly restructures the
     * tree if a more efficient configuration can be found with
     * the new dimensions. Bounds can be given either as a
     * single {@link Rect} or as any combination of arguments
     * which is valid for the {@link Rect} constructor.
     * @this {Quadtree}
     * @param {T} obj the object to insert
     * @param {Rect|Point|number} x The Rect bounds of the object, or top-left Point, or x value.
     * @param {Point|Size|number} y Bottom-right Point or Size or y value.
     * @param {number} w Width to be used if x,y are specified;
     * must be non-negative.
     * @param {number} h Height to be used if x,y are specified;
     * @return {void}
     */
    add(obj, x, y, w, h) {
        let bounds;
        if (!(obj instanceof QuadObj) && (x === undefined || x === null)) {
            throw new Error('Invalid bounds for added object');
        }
        if (x instanceof go.Rect) {
            bounds = x.copy();
        }
        else {
            bounds = new go.Rect(x, y, w, h);
        }
        let treeObj;
        if (obj instanceof QuadObj) {
            treeObj = obj;
            obj = treeObj.obj;
            bounds = treeObj.bounds;
        }
        else {
            treeObj = new QuadObj(bounds, obj);
        }
        if (isNaN(bounds.x) || bounds.x === Infinity ||
            isNaN(bounds.y) || bounds.y === Infinity ||
            isNaN(bounds.width) || bounds.width === Infinity ||
            isNaN(bounds.height) || bounds.height === Infinity) {
            throw new Error('Invalid rectangle, contains NaN or Infinity properties');
        }
        this._hasZeroWidthObject = this._hasZeroWidthObject || bounds.width === 0;
        this._hasZeroHeightObject = this._hasZeroHeightObject || bounds.height === 0;
        // initialize bounds of tree as the max width or height of the first object added
        if (this._root.bounds.width === 0 || this._root.bounds.height === 0) {
            const len = Math.max(bounds.width, bounds.height);
            this._root.bounds = new go.Rect(bounds.x, bounds.y, len, len);
        }
        // fixes quadtree having a width and height of 0 if the first object added is a point
        // this will only be called after a second object is added, the new width/height is the maximum distance between them
        if (this._root.bounds !== undefined && (this._root.bounds.width === 0 || this._root.bounds.height === 0)) {
            const len = Math.max(Math.abs(bounds.x - this._root.bounds.x), Math.abs(bounds.y - this._root.bounds.y));
            this._root.bounds = new go.Rect(Math.min(this._root.bounds.x, bounds.x), Math.min(this._root.bounds.y, bounds.y), len, len);
        }
        // map the object to its corresponding QuadObj (so that the bounds of this object can be retrieved later)
        this._treeObjectMap.add(obj, treeObj);
        // grow as many times as necessary to fit the new object
        while (!this._root.bounds.containsRect(bounds)) {
            const old = this._root;
            this.walk(n => n.level++, old);
            const intersectsTopBound = bounds.y < this._root.bounds.y;
            const intersectsBottomBound = bounds.y + bounds.height > this._root.bounds.y + this._root.bounds.height;
            const intersectsRightBound = bounds.x + bounds.width > this._root.bounds.x + this._root.bounds.width;
            const intersectsLeftBound = bounds.x < this._root.bounds.x;
            if ((intersectsTopBound && intersectsRightBound) || (intersectsTopBound && !intersectsLeftBound)) {
                /*  _______
                 * | 1 | 0 |
                 * |___|___|
                 * |old| 3 |
                 * |___|___|
                 */
                const newBounds = new go.Rect(this._root.bounds.x, this._root.bounds.y - this._root.bounds.height, this._root.bounds.width * 2, this._root.bounds.height * 2);
                this._root = new QuadNode(newBounds, null, 0);
                this._root.split();
                this._root.nodes[2] = old;
                this._root.totalObjects = old.totalObjects;
                old.parent = this._root;
                this._restructure(old);
                this._restructureLevels(old);
                if (this._hasZeroHeightObject) {
                    this._fixTopObjectPlacement(old);
                }
            }
            else if (intersectsTopBound && intersectsLeftBound) {
                /*  _______
                 * | 1 | 0 |
                 * |___|___|
                 * | 2 |old|
                 * |___|___|
                 */
                const newBounds = new go.Rect(this._root.bounds.x - this._root.bounds.width, this._root.bounds.y - this._root.bounds.height, this._root.bounds.width * 2, this._root.bounds.height * 2);
                this._root = new QuadNode(newBounds, null, 0);
                this._root.split();
                this._root.nodes[3] = old;
                this._root.totalObjects = old.totalObjects;
                old.parent = this._root;
                this._restructure(old);
                this._restructureLevels(old);
                if (this._hasZeroWidthObject) {
                    this._fixLeftObjectPlacement(old);
                }
                if (this._hasZeroHeightObject) {
                    this._fixTopObjectPlacement(old);
                }
            }
            else if ((intersectsBottomBound && intersectsRightBound) || ((intersectsRightBound || intersectsBottomBound) && !intersectsLeftBound)) {
                /*  _______
                 * |old| 0 |
                 * |___|___|
                 * | 2 | 3 |
                 * |___|___|
                 */
                const newBounds = new go.Rect(this._root.bounds.x, this._root.bounds.y, this._root.bounds.width * 2, this._root.bounds.height * 2);
                this._root = new QuadNode(newBounds, null, 0);
                this._root.split();
                this._root.nodes[1] = old;
                this._root.totalObjects = old.totalObjects;
                old.parent = this._root;
                this._restructure(old);
                this._restructureLevels(old);
            }
            else if ((intersectsBottomBound && intersectsLeftBound) || intersectsLeftBound) {
                /*  _______
                 * | 1 |old|
                 * |___|___|
                 * | 2 | 3 |
                 * |___|___|
                 */
                const newBounds = new go.Rect(this._root.bounds.x - this._root.bounds.width, this._root.bounds.y, this._root.bounds.width * 2, this._root.bounds.height * 2);
                this._root = new QuadNode(newBounds, null, 0);
                this._root.split();
                this._root.nodes[0] = old;
                this._root.totalObjects = old.totalObjects;
                old.parent = this._root;
                this._restructure(old);
                this._restructureLevels(old);
                if (this._hasZeroWidthObject) {
                    this._fixLeftObjectPlacement(old);
                }
            }
        }
        // add the object to the tree
        this._addHelper(this._root, treeObj);
    }
    /**
     * @hidden @internal
     * Helper function to recursively perform the add operation
     * on the tree.
     * @this {Quadtree}
     * @param {QuadNode<T>} root the current node being operated on
     * @param {QuadObj<T>} treeObj the object being added
     * @return {void}
     */
    _addHelper(root, treeObj) {
        root.totalObjects++;
        if (root.nodes[0]) {
            const index = this._getIndex(treeObj.bounds, root);
            if (index !== -1) {
                const selected = root.nodes[index];
                if (selected !== null) {
                    this._addHelper(selected, treeObj);
                    return;
                }
            }
        }
        root.treeObjects.push(treeObj);
        root.objects.push(treeObj.obj);
        if (root.treeObjects.length > this._nodeCapacity && root.level < this._maxLevels) {
            if (!root.nodes[0]) {
                root.split();
            }
            let i = 0;
            while (i < root.treeObjects.length) {
                const index = this._getIndex(root.treeObjects[i].bounds, root);
                if (index !== -1 && !(root.treeObjects[i].bounds.width === 0 || root.treeObjects[i].bounds.height === 0)) {
                    root.objects.splice(i, 1);
                    const selected = root.nodes[index];
                    if (selected !== null) {
                        this._addHelper(selected, root.treeObjects.splice(i, 1)[0]);
                    }
                }
                else {
                    i++;
                }
            }
        }
    }
    /**
     * @hidden @internal
     * Recursively moves objects placed on the right side of a vertical border
     * between two nodes to the left side of the vertical border. This allows
     * them to be located by {@link #_getIndex}. This function is called
     * after an {@link #add} call grows the Quadtree, but only if there
     * are 0 width objects in the tree.
     * @this {Quadtree}
     * @param {QuadNode<T>} root the current root node being operated on
     * @return {void}
     */
    _fixLeftObjectPlacement(root) {
        const nw = root.nodes[1];
        if (nw !== null) { // if root is split
            this._fixLeftObjectPlacement(nw); // NW
            const sw = root.nodes[2];
            if (sw !== null) {
                this._fixLeftObjectPlacement(sw); // SW
            }
        }
        const toRemove = [];
        const toAdd = [];
        for (let i = 0; i < root.objects.length; i++) {
            const obj = root.treeObjects[i];
            if (obj.bounds.width === 0 && obj.bounds.x === root.bounds.x) {
                toRemove.push(i);
                toAdd.push(obj);
            }
        }
        this._removeFromOwner(root, toRemove);
        for (const obj of toAdd) {
            this.add(obj.obj, obj.bounds);
        }
    }
    /**
     * @hidden @internal
     * Recursively moves objects placed on the bottom side of a horizontal border
     * between two nodes to the top side of the vertical border. This allows
     * them to be located by {@link #_getIndex}. This function is called
     * after an {@link #add} call grows the Quadtree, but only if there
     * are 0 height objects in the tree.
     * @this {Quadtree}
     * @param {QuadNode<T>} root the current root node being operated on
     * @return {void}
     */
    _fixTopObjectPlacement(root) {
        const ne = root.nodes[0];
        if (ne !== null) { // if root is split
            this._fixTopObjectPlacement(ne); // NE
            const nw = root.nodes[1];
            if (nw !== null) {
                this._fixTopObjectPlacement(nw); // NW
            }
        }
        const toRemove = [];
        const toAdd = [];
        for (let i = 0; i < root.objects.length; i++) {
            const obj = root.treeObjects[i];
            if (obj.bounds.height === 0 && obj.bounds.y === root.bounds.y) {
                toRemove.push(i);
                toAdd.push(obj);
            }
        }
        this._removeFromOwner(root, toRemove);
        for (const obj of toAdd) {
            this.add(obj);
        }
    }
    /**
     * @hidden @internal
     * Moves all objects from a leaf node to its parent and unsplits.
     * Used after growing the tree when level>max level.
     * @this {Quadtree}
     * @param {QuadNode<T>} node the leaf node to restructure
     * @return {void}
     */
    _restructureLevels(node) {
        if (node && this._maxLevels < Infinity && node.nodes[0] !== null) {
            if (node.level >= this._maxLevels) {
                for (let i = 0; i < node.nodes.length; i++) {
                    const selected = node.nodes[i];
                    if (selected !== null) {
                        node.objects.push.apply(node.objects, selected.objects);
                        node.treeObjects.push.apply(node.treeObjects, selected.treeObjects);
                        selected.clear();
                        node.nodes[i] = null;
                    }
                }
            }
            else {
                for (let i = 0; i < node.nodes.length; i++) {
                    const selected = node.nodes[i];
                    if (selected !== null) {
                        this._restructureLevels(selected);
                    }
                }
            }
        }
    }
    /**
     * Return the node that contains the given object.
     * @this {Quadtree}
     * @param {T} obj the object to find
     * @return {QuadNode<T>} the node containing the given object, null if the object is not found
     */
    find(obj) {
        const treeObj = this._treeObjectMap.get(obj);
        if (treeObj) {
            return this._findHelper(this._root, treeObj);
        }
        return null;
    }
    _findHelper(root, treeObj) {
        for (const object of root.treeObjects) {
            if (object === treeObj) {
                return root;
            }
        }
        const index = this._getIndex(treeObj.bounds, root);
        const selected = index === -1 ? null : root.nodes[index];
        if (selected !== null) {
            const result = this._findHelper(selected, treeObj);
            if (result) {
                return result;
            }
        }
        return null;
    }
    /**
     * Convenience method, calls {@link #find} and returns a boolean
     * indicating whether or not the tree contains the given object
     * @this {Quadtree}
     * @param {T} obj the object to check for
     * @return {boolean} whether or not the given object is present in the tree
     */
    has(obj) {
        return !!this.find(obj);
    }
    /**
     * Checks if any of the objects in the tree have the given boundaries
     * @this {Quadtree}
     * @param {Rect} bounds the rectangle to check for
     * @return {Rect} the actual bounds object stored in the tree
     */
    findBounds(bounds) {
        if (bounds) {
            return this._findBoundsHelper(this._root, bounds);
        }
        return null;
    }
    _findBoundsHelper(root, bounds) {
        for (const object of root.treeObjects) {
            if (bounds.equalsApprox(object.bounds)) {
                return bounds;
            }
        }
        const index = this._getIndex(bounds, root);
        const selected = index === -1 ? null : root.nodes[index];
        if (selected !== null) {
            return this._findBoundsHelper(selected, bounds);
        }
        return null;
    }
    /**
     * Remove the given object from the tree, restructuring to
     * get rid of empty nodes that are unneeded.
     * @this {Quadtree}
     * @param {T} obj the object to remove
     * @return {boolean} whether or not the deletion was successful. False when the object is not in the tree.
     */
    remove(obj) {
        const treeObj = this._treeObjectMap.get(obj);
        if (treeObj) {
            const owner = this._findHelper(this._root, treeObj);
            if (owner) {
                owner.treeObjects.splice(owner.treeObjects.indexOf(treeObj), 1);
                owner.objects.splice(owner.objects.indexOf(obj), 1);
                owner.totalObjects--;
                this._treeObjectMap.remove(obj);
                let parent = owner.parent;
                while (parent) {
                    parent.totalObjects--;
                    parent = parent.parent;
                }
                if (owner.nodes[0] && owner.totalObjects <= this._nodeCapacity) {
                    this._addChildObjectsToNode(owner, owner);
                    for (let i = 0; i < owner.nodes.length; i++) {
                        const selected = owner.nodes[i];
                        if (selected !== null) {
                            selected.clear();
                        }
                        owner.nodes[i] = null;
                    }
                }
                this._restructure(owner);
                return true;
            }
        }
        return false;
    }
    /**
     * Removes multiple objects at the given indices from the given owner. Similar
     * to the normal remove function, but much faster when the owner and indices are
     * already known.
     * @this {Quadtree}
     * @param {QuadNode<T>} owner the node to remove objects from
     * @param {Array<number>} indexes the indices to remove. Should be given in ascending order.
     */
    _removeFromOwner(owner, indexes) {
        if (indexes.length === 0) {
            return;
        }
        for (let i = indexes.length - 1; i >= 0; i--) {
            this._treeObjectMap.remove(owner.objects[indexes[i]]);
            owner.treeObjects.splice(indexes[i], 1);
            owner.objects.splice(indexes[i], 1);
        }
        owner.totalObjects -= indexes.length;
        let parent = owner.parent;
        while (parent) {
            parent.totalObjects -= indexes.length;
            parent = parent.parent;
        }
        if (owner.nodes[0] && owner.totalObjects <= this._nodeCapacity) {
            this._addChildObjectsToNode(owner, owner);
            for (let i = 0; i < owner.nodes.length; i++) {
                const selected = owner.nodes[i];
                if (selected !== null) {
                    selected.clear();
                }
                owner.nodes[i] = null;
            }
        }
        this._restructure(owner);
    }
    /**
     * @hidden @internal
     * Recursively adds all objects from children of the given
     * root tree to the given owner tree
     * Used internally by {@link #remove}
     * @this {Quadtree}
     * @param {Quadtree} owner the tree to add objects to
     * @return {void}
     */
    _addChildObjectsToNode(owner, root) {
        for (const node of root.nodes) {
            if (node) {
                owner.treeObjects.push.apply(owner.treeObjects, node.treeObjects);
                owner.objects.push.apply(owner.objects, node.objects);
                this._addChildObjectsToNode(owner, node);
            }
        }
    }
    /**
     * @hidden @internal
     * Recursively combines parent nodes that should be split, all the way
     * up the tree. Starts from the given node.
     * @this {Quadtree}
     * @return {void}
     */
    _restructure(root) {
        const parent = root.parent;
        if (parent) {
            // if none of the child nodes have any objects, the parent should not be split
            let childrenHaveNoObjects = true;
            for (const node of parent.nodes) {
                if (node !== null && node.totalObjects > 0) {
                    childrenHaveNoObjects = false;
                    break;
                }
            }
            // unsplit children and move nodes to parent
            if (parent.totalObjects <= this._nodeCapacity || childrenHaveNoObjects) {
                for (let i = 0; i < parent.nodes.length; i++) {
                    const selected = parent.nodes[i];
                    if (selected !== null) {
                        parent.objects.push.apply(parent.objects, selected.objects);
                        parent.treeObjects.push.apply(parent.treeObjects, selected.treeObjects);
                        selected.clear();
                        parent.nodes[i] = null;
                    }
                }
                this._restructure(parent);
            }
        }
    }
    /**
     * Can be called as either (obj, x, y) or (obj, point). Translate
     * the given object to given x and y coordinates or to a given {@link Point}.
     * @this {Quadtree}
     * @param {T} obj the object to move
     * @param {number|Point} x the x coordinate or Point to move the object to
     * @param {number} y the y coordinate to move the object to
     * @return {boolean} whether or not the move was successful. False if the object was not in the tree.
     */
    move(obj, x, y) {
        const treeObj = this._treeObjectMap.get(obj);
        if (treeObj && this.remove(obj)) {
            if (x instanceof go.Point) {
                treeObj.bounds.x = x.x;
                treeObj.bounds.y = x.y;
            }
            else if (y !== undefined) {
                treeObj.bounds.x = x;
                treeObj.bounds.y = y;
            }
            else {
                throw new Error('Please provide the position as either a Point or two numbers');
            }
            this.add(treeObj);
            return true;
        }
        return false;
    }
    /**
     * Can be called as either (obj, width, height) or (obj, size). Resize
     * the given object to given width and height or to a given {@link Size}.
     * @this {Quadtree}
     * @param {T} obj the object to resize
     * @param {number|Size} width the width or Size to resize the object to
     * @param {number} height the height to resize the object to
     * @return {boolean} whether or not the resize was successful. False if the object was not in the tree.
     */
    resize(obj, width, height) {
        const treeObj = this._treeObjectMap.get(obj);
        if (treeObj && this.remove(obj)) {
            if (width instanceof go.Size) {
                treeObj.bounds.width = width.width;
                treeObj.bounds.height = width.height;
            }
            else if (height !== undefined) {
                treeObj.bounds.width = width;
                treeObj.bounds.height = height;
            }
            else {
                throw new Error('Please provide the size as either a Size or two numbers');
            }
            this.add(treeObj);
            return true;
        }
        return false;
    }
    /**
     * Updates the given object to have the bounds given, provided as either a
     * {@link Rect} or x, y, width, and height.
     * @this {Quadtree}
     * @param obj the object to change the bounds of
     * @param x the x-coordinate or Rect to set the object to
     * @param y the y-coordinate to set the object to, unnecessary if a Rect was given
     * @param width the width to set the object to, unnecessary if a Rect was given
     * @param height the height to set the object to, unnecessary if a Rect was given
     */
    setTo(obj, x, y, width, height) {
        const treeObj = this._treeObjectMap.get(obj);
        if (treeObj && this.remove(obj)) {
            if (x instanceof go.Rect) {
                treeObj.bounds.set(x);
            }
            else if (y !== undefined && width !== undefined && height !== undefined) {
                treeObj.bounds.setTo(x, y, width, height);
            }
            else {
                throw new Error('Please provide new bounds as either a Rect or combination of four numbers (x, y, width, height)');
            }
            this.add(treeObj);
            return true;
        }
        return false;
    }
    /**
     * Return all objects that intersect (wholly or partially) with
     * the given {@link Rect} or {@link Point}. Touching edges and
     * objects overlapping by 1e-7 or less (to account for floating
     * point error) are both not considered intersections.
     * @this {Quadtree}
     * @param {Rect|Point} rect the Rect or Point to check intersections for. If a point is given, a Rect with size (0, 0) is created for intersection calculations.
     * @return {Array<T>} array containing all intersecting objects
     */
    intersecting(rect) {
        if (rect instanceof go.Point) {
            rect = new go.Rect(rect.x, rect.y, 0, 0);
        }
        const returnObjects = [];
        this._intersectingHelper(rect, this._root, returnObjects);
        return returnObjects;
    }
    _intersectingHelper(rect, root, returnObjects) {
        const index = this._getIndex(rect, root);
        const selected = index === -1 ? null : root.nodes[index];
        if (selected !== null) {
            this._intersectingHelper(rect, selected, returnObjects);
        }
        else if (root.nodes[0] !== null) {
            const quadrants = this._getQuadrants(rect, root);
            for (const quadrant of quadrants) {
                const node = root.nodes[quadrant];
                if (node !== null) {
                    this._intersectingHelper(rect, node, returnObjects);
                }
            }
        }
        for (const obj of root.treeObjects) {
            if (Quadtree._rectsIntersect(obj.bounds, rect)) {
                returnObjects.push(obj.obj);
            }
        }
    }
    /**
     * @hidden @internal
     * Similar as {@link Rect.intersectsRect}, but doesn't count edges as intersections.
     * Also accounts for floating error (by returning false more often) up to an error of 1e-7.
     * Used by {@link #intersecting}.
     * @this {Quadtree}
     * @param {Rect} r1 first rectangle
     * @param {Rect} r2 second rectangle
     * @return {boolean} whether or not the two rectangles intersect
     */
    static _rectsIntersect(r1, r2) {
        return !(r2.left + 1e-7 >= r1.right || r2.right - 1e-7 <= r1.left || r2.top + 1e-7 >= r1.bottom || r2.bottom - 1e-7 <= r1.top);
    }
    /**
     * Return all objects that fully contain the given {@link Rect} or {@link Point}.
     * @this {Quadtree}
     * @param {Rect|Point} rect the Rect or Point to check containing for. If a point is given, a Rect with size (0, 0) is created for containment calculations.
     * @return {Array<T>} array containing all containing objects
     */
    containing(rect) {
        if (rect instanceof go.Point) {
            rect = new go.Rect(rect.x, rect.y, 0, 0);
        }
        const returnObjects = [];
        this._containingHelper(rect, this._root, returnObjects);
        return returnObjects;
    }
    _containingHelper(rect, root, returnObjects) {
        const index = this._getIndex(rect, root);
        const selected = index === -1 ? null : root.nodes[index];
        if (selected !== null) {
            this._containingHelper(rect, selected, returnObjects);
        }
        else if (root.nodes[0]) {
            const quadrants = this._getQuadrants(rect, root);
            for (const quadrant of quadrants) {
                const node = root.nodes[quadrant];
                if (node !== null) {
                    this._containingHelper(rect, node, returnObjects);
                }
            }
        }
        for (const obj of root.treeObjects) {
            if (obj.bounds.containsRect(rect)) {
                returnObjects.push(obj.obj);
            }
        }
    }
    /**
     * Returns the square of the distance from the centers of the given objects
     * @this {Quadtree}
     * @param {T} obj1
     * @param {T} obj2
     * @return {number} square of the distance between the centers of obj1 and obj2
     */
    distanceSquared(obj1, obj2) {
        const owner1 = this.find(obj1);
        const owner2 = this.find(obj2);
        if (owner1 !== null && owner2 !== null) {
            const treeObj1 = this._treeObjectMap.get(obj1);
            const treeObj2 = this._treeObjectMap.get(obj2);
            if (treeObj1 !== null && treeObj2 !== null) {
                return treeObj1.bounds.center.distanceSquaredPoint(treeObj2.bounds.center);
            }
        }
        return -1;
    }
    /**
     * Recursively traverses the tree (depth first) and executes the
     * given callback on each node.
     * @this {Quadtree}
     * @param {function} callback the callback to execute on each node. Takes the form of (n: Quadtree) => void
     * @param {boolean} root whether or not to execute the callback on the root node as well. Defaults to true
     * @return {void}
     */
    walk(callback, node = this._root, root = true) {
        if (root) {
            root = false;
            callback(node);
        }
        for (const n of node.nodes) {
            if (n) {
                callback(n);
                this.walk(callback, n, root);
            }
        }
    }
    /**
     * Visits every object stored in the tree (depth first)
     * @this {Quadtree}
     * @param {function} callback the callback to execute on each object.
     * @return {void}
     */
    forEach(callback) {
        this.walk((n) => {
            for (const obj of n.objects) {
                callback(obj);
            }
        });
    }
    /**
     * Finds the most furthest object in each direction stored in the tree.
     * Bounds are tested using the center x and y coordinate.
     * @this {Quadtree}
     * @return {Array<T>} maximum and minimum objects in the tree, in the format [min x, max x, min y, max y].
     */
    findExtremeObjects() {
        const [extremes0, extremes1, extremes2, extremes3] = this._findExtremeObjectsHelper();
        return [
            extremes0 !== null ? extremes0.obj : null,
            extremes1 !== null ? extremes1.obj : null,
            extremes2 !== null ? extremes2.obj : null,
            extremes3 !== null ? extremes3.obj : null
        ];
    }
    /**
     * @hidden @internal
     * Recursive helper function for {@link #findExtremeObjects}
     * @this {Quadtree}
     * @param {QuadNode<T>} root the current root node being searched
     * @return {Array<QuadObj<T>>} maximum and minimum objects in the tree, in the format [min x, max x, min y, max y].
     */
    _findExtremeObjectsHelper(root = this._root) {
        let minX = null;
        let maxX = null;
        let minY = null;
        let maxY = null;
        if (root.nodes[0]) { // if root is split
            for (const node of root.nodes) {
                if (node !== null) {
                    const [extremes0, extremes1, extremes2, extremes3] = this._findExtremeObjectsHelper(node);
                    if (minX == null || (extremes0 !== null && extremes0.bounds.centerX < minX.bounds.centerX)) {
                        minX = extremes0;
                    }
                    if (maxX === null || (extremes1 !== null && extremes1.bounds.centerX > maxX.bounds.centerX)) {
                        maxX = extremes1;
                    }
                    if (minY === null || (extremes2 !== null && extremes2.bounds.centerY < minY.bounds.centerY)) {
                        minY = extremes2;
                    }
                    if (maxY === null || (extremes3 !== null && extremes3.bounds.centerY > maxY.bounds.centerY)) {
                        maxY = extremes3;
                    }
                }
            }
        }
        for (const obj of root.treeObjects) {
            if (!minX || obj.bounds.centerX < minX.bounds.centerX) {
                minX = obj;
            }
            if (!maxX || obj.bounds.centerX > maxX.bounds.centerX) {
                maxX = obj;
            }
            if (!minY || obj.bounds.centerY < minY.bounds.centerY) {
                minY = obj;
            }
            if (!maxY || obj.bounds.centerY > maxY.bounds.centerY) {
                maxY = obj;
            }
        }
        return [minX, maxX, minY, maxY];
    }
}