vis.js is a dynamic, browser-based visualization library
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'use strict';
let util = require('../../util');
import NetworkUtil from '../NetworkUtil';
class LayoutEngine {
constructor(body) {
this.body = body;
this.initialRandomSeed = Math.round(Math.random() * 1000000);
this.randomSeed = this.initialRandomSeed;
this.options = {};
this.optionsBackup = {};
this.defaultOptions = {
randomSeed: undefined,
improvedLayout: true,
hierarchical: {
enabled:false,
levelSeparation: 150,
direction: 'UD', // UD, DU, LR, RL
sortMethod: 'hubsize' // hubsize, directed
}
};
util.extend(this.options, this.defaultOptions);
this.lastNodeOnLevel = {};
this.hierarchicalParents = {};
this.hierarchicalChildren = {};
this.distributionOrdering = {};
this.distributionOrderingPresence = {};
this.bindEventListeners();
}
bindEventListeners() {
this.body.emitter.on('_dataChanged', () => {
this.setupHierarchicalLayout();
});
this.body.emitter.on('_dataLoaded', () => {
this.layoutNetwork();
});
this.body.emitter.on('_resetHierarchicalLayout', () => {
this.setupHierarchicalLayout();
});
}
setOptions(options, allOptions) {
if (options !== undefined) {
let prevHierarchicalState = this.options.hierarchical.enabled;
util.selectiveDeepExtend(["randomSeed", "improvedLayout"],this.options, options);
util.mergeOptions(this.options, options, 'hierarchical');
if (options.randomSeed !== undefined) {this.initialRandomSeed = options.randomSeed;}
if (this.options.hierarchical.enabled === true) {
if (prevHierarchicalState === true) {
// refresh the overridden options for nodes and edges.
this.body.emitter.emit('refresh', true);
}
// make sure the level separation is the right way up
if (this.options.hierarchical.direction === 'RL' || this.options.hierarchical.direction === 'DU') {
if (this.options.hierarchical.levelSeparation > 0) {
this.options.hierarchical.levelSeparation *= -1;
}
}
else {
if (this.options.hierarchical.levelSeparation < 0) {
this.options.hierarchical.levelSeparation *= -1;
}
}
this.body.emitter.emit('_resetHierarchicalLayout');
// because the hierarchical system needs it's own physics and smooth curve settings, we adapt the other options if needed.
return this.adaptAllOptionsForHierarchicalLayout(allOptions);
}
else {
if (prevHierarchicalState === true) {
// refresh the overridden options for nodes and edges.
this.body.emitter.emit('refresh');
return util.deepExtend(allOptions,this.optionsBackup);
}
}
}
return allOptions;
}
adaptAllOptionsForHierarchicalLayout(allOptions) {
if (this.options.hierarchical.enabled === true) {
// set the physics
if (allOptions.physics === undefined || allOptions.physics === true) {
allOptions.physics = {solver: 'hierarchicalRepulsion'};
this.optionsBackup.physics = {solver:'barnesHut'};
}
else if (typeof allOptions.physics === 'object') {
this.optionsBackup.physics = {solver:'barnesHut'};
if (allOptions.physics.solver !== undefined) {
this.optionsBackup.physics = {solver:allOptions.physics.solver};
}
allOptions.physics['solver'] = 'hierarchicalRepulsion';
}
else if (allOptions.physics !== false) {
this.optionsBackup.physics = {solver:'barnesHut'};
allOptions.physics['solver'] = 'hierarchicalRepulsion';
}
// get the type of static smooth curve in case it is required
let type = 'horizontal';
if (this.options.hierarchical.direction === 'RL' || this.options.hierarchical.direction === 'LR') {
type = 'vertical';
}
// disable smooth curves if nothing is defined. If smooth curves have been turned on, turn them into static smooth curves.
if (allOptions.edges === undefined) {
this.optionsBackup.edges = {smooth:{enabled:true, type:'dynamic'}};
allOptions.edges = {smooth: false};
}
else if (allOptions.edges.smooth === undefined) {
this.optionsBackup.edges = {smooth:{enabled:true, type:'dynamic'}};
allOptions.edges.smooth = false;
}
else {
if (typeof allOptions.edges.smooth === 'boolean') {
this.optionsBackup.edges = {smooth:allOptions.edges.smooth};
allOptions.edges.smooth = {enabled: allOptions.edges.smooth, type:type}
}
else {
// allow custom types except for dynamic
if (allOptions.edges.smooth.type !== undefined && allOptions.edges.smooth.type !== 'dynamic') {
type = allOptions.edges.smooth.type;
}
this.optionsBackup.edges = {
smooth: allOptions.edges.smooth.enabled === undefined ? true : allOptions.edges.smooth.enabled,
type:allOptions.edges.smooth.type === undefined ? 'dynamic' : allOptions.edges.smooth.type,
roundness: allOptions.edges.smooth.roundness === undefined ? 0.5 : allOptions.edges.smooth.roundness,
forceDirection: allOptions.edges.smooth.forceDirection === undefined ? false : allOptions.edges.smooth.forceDirection
};
allOptions.edges.smooth = {
enabled: allOptions.edges.smooth.enabled === undefined ? true : allOptions.edges.smooth.enabled,
type:type,
roundness: allOptions.edges.smooth.roundness === undefined ? 0.5 : allOptions.edges.smooth.roundness,
forceDirection: allOptions.edges.smooth.forceDirection === undefined ? false : allOptions.edges.smooth.forceDirection
}
}
}
// force all edges into static smooth curves. Only applies to edges that do not use the global options for smooth.
this.body.emitter.emit('_forceDisableDynamicCurves', type);
}
return allOptions;
}
seededRandom() {
let x = Math.sin(this.randomSeed++) * 10000;
return x - Math.floor(x);
}
positionInitially(nodesArray) {
if (this.options.hierarchical.enabled !== true) {
this.randomSeed = this.initialRandomSeed;
for (let i = 0; i < nodesArray.length; i++) {
let node = nodesArray[i];
let radius = 10 * 0.1 * nodesArray.length + 10;
let angle = 2 * Math.PI * this.seededRandom();
if (node.x === undefined) {
node.x = radius * Math.cos(angle);
}
if (node.y === undefined) {
node.y = radius * Math.sin(angle);
}
}
}
}
/**
* Use Kamada Kawai to position nodes. This is quite a heavy algorithm so if there are a lot of nodes we
* cluster them first to reduce the amount.
*/
layoutNetwork() {
if (this.options.hierarchical.enabled !== true && this.options.improvedLayout === true) {
// first check if we should Kamada Kawai to layout. The threshold is if less than half of the visible
// nodes have predefined positions we use this.
let positionDefined = 0;
for (let i = 0; i < this.body.nodeIndices.length; i++) {
let node = this.body.nodes[this.body.nodeIndices[i]];
if (node.predefinedPosition === true) {
positionDefined += 1;
}
}
// if less than half of the nodes have a predefined position we continue
if (positionDefined < 0.5 * this.body.nodeIndices.length) {
let MAX_LEVELS = 10;
let level = 0;
let clusterThreshold = 100;
// if there are a lot of nodes, we cluster before we run the algorithm.
if (this.body.nodeIndices.length > clusterThreshold) {
let startLength = this.body.nodeIndices.length;
while (this.body.nodeIndices.length > clusterThreshold) {
//console.time("clustering")
level += 1;
let before = this.body.nodeIndices.length;
// if there are many nodes we do a hubsize cluster
if (level % 3 === 0) {
this.body.modules.clustering.clusterBridges();
}
else {
this.body.modules.clustering.clusterOutliers();
}
let after = this.body.nodeIndices.length;
if ((before == after && level % 3 !== 0) || level > MAX_LEVELS) {
this._declusterAll();
this.body.emitter.emit("_layoutFailed");
console.info("This network could not be positioned by this version of the improved layout algorithm. Please disable improvedLayout for better performance.");
return;
}
//console.timeEnd("clustering")
//console.log(level,after)
}
// increase the size of the edges
this.body.modules.kamadaKawai.setOptions({springLength: Math.max(150, 2 * startLength)})
}
// position the system for these nodes and edges
this.body.modules.kamadaKawai.solve(this.body.nodeIndices, this.body.edgeIndices, true);
// shift to center point
this._shiftToCenter();
// perturb the nodes a little bit to force the physics to kick in
let offset = 70;
for (let i = 0; i < this.body.nodeIndices.length; i++) {
this.body.nodes[this.body.nodeIndices[i]].x += (0.5 - this.seededRandom())*offset;
this.body.nodes[this.body.nodeIndices[i]].y += (0.5 - this.seededRandom())*offset;
}
// uncluster all clusters
this._declusterAll();
// reposition all bezier nodes.
this.body.emitter.emit("_repositionBezierNodes");
}
}
}
/**
* Move all the nodes towards to the center so gravitational pull wil not move the nodes away from view
* @private
*/
_shiftToCenter() {
let range = NetworkUtil.getRangeCore(this.body.nodes, this.body.nodeIndices);
let center = NetworkUtil.findCenter(range);
for (let i = 0; i < this.body.nodeIndices.length; i++) {
this.body.nodes[this.body.nodeIndices[i]].x -= center.x;
this.body.nodes[this.body.nodeIndices[i]].y -= center.y;
}
}
_declusterAll() {
let clustersPresent = true;
while (clustersPresent === true) {
clustersPresent = false;
for (let i = 0; i < this.body.nodeIndices.length; i++) {
if (this.body.nodes[this.body.nodeIndices[i]].isCluster === true) {
clustersPresent = true;
this.body.modules.clustering.openCluster(this.body.nodeIndices[i], {}, false);
}
}
if (clustersPresent === true) {
this.body.emitter.emit('_dataChanged');
}
}
}
getSeed() {
return this.initialRandomSeed;
}
/**
* This is the main function to layout the nodes in a hierarchical way.
* It checks if the node details are supplied correctly
*
* @private
*/
setupHierarchicalLayout() {
if (this.options.hierarchical.enabled === true && this.body.nodeIndices.length > 0) {
// get the size of the largest hubs and check if the user has defined a level for a node.
let node, nodeId;
let definedLevel = false;
let undefinedLevel = false;
this.hierarchicalLevels = {};
this.nodeSpacing = 100;
for (nodeId in this.body.nodes) {
if (this.body.nodes.hasOwnProperty(nodeId)) {
node = this.body.nodes[nodeId];
if (node.options.level !== undefined) {
definedLevel = true;
this.hierarchicalLevels[nodeId] = node.options.level;
}
else {
undefinedLevel = true;
}
}
}
// if the user defined some levels but not all, alert and run without hierarchical layout
if (undefinedLevel === true && definedLevel === true) {
throw new Error('To use the hierarchical layout, nodes require either no predefined levels or levels have to be defined for all nodes.');
return;
}
else {
// define levels if undefined by the users. Based on hubsize.
if (undefinedLevel === true) {
if (this.options.hierarchical.sortMethod === 'hubsize') {
this._determineLevelsByHubsize();
}
else if (this.options.hierarchical.sortMethod === 'directed') {
this._determineLevelsDirected();
}
else if (this.options.hierarchical.sortMethod === 'custom') {
this._determineLevelsCustomCallback();
}
}
// check the distribution of the nodes per level.
let distribution = this._getDistribution();
// get the parent children relations.
this._generateMap();
// place the nodes on the canvas.
this._placeNodesByHierarchy(distribution);
// Todo: condense the whitespace.
this._condenseHierarchy(distribution);
// shift to center so gravity does not have to do much
this._shiftToCenter();
}
}
}
/**
* @private
*/
_condenseHierarchy(distribution) {
//console.log(this.distributionOrdering);
//let iterations = 10;
//for (let i = 0; i < iterations; i++) {
//}
}
_removeWhiteSpace(distribution) {
}
/**
* This function places the nodes on the canvas based on the hierarchial distribution.
*
* @param {Object} distribution | obtained by the function this._getDistribution()
* @private
*/
_placeNodesByHierarchy(distribution) {
this.positionedNodes = {};
// start placing all the level 0 nodes first. Then recursively position their branches.
for (let level in distribution) {
if (distribution.hasOwnProperty(level)) {
// sort nodes in level by position:
let nodeArray = Object.keys(distribution[level]);
nodeArray = this._indexArrayToNodes(nodeArray);
this._sortNodeArray(nodeArray);
for (let i = 0; i < nodeArray.length; i++) {
let node = nodeArray[i];
if (this.positionedNodes[node.id] === undefined) {
this._setPositionForHierarchy(node, this.nodeSpacing * i, level);
this.positionedNodes[node.id] = true;
this._placeBranchNodes(node.id, level);
}
}
}
}
}
/**
* Receives an array with node indices and returns an array with the actual node references. Used for sorting based on
* node properties.
* @param idArray
*/
_indexArrayToNodes(idArray) {
let array = [];
for (let i = 0; i < idArray.length; i++) {
array.push(this.body.nodes[idArray[i]])
}
return array;
}
/**
* This function get the distribution of levels based on hubsize
*
* @returns {Object}
* @private
*/
_getDistribution() {
let distribution = {};
let nodeId, node;
// we fix Y because the hierarchy is vertical, we fix X so we do not give a node an x position for a second time.
// the fix of X is removed after the x value has been set.
for (nodeId in this.body.nodes) {
if (this.body.nodes.hasOwnProperty(nodeId)) {
node = this.body.nodes[nodeId];
let level = this.hierarchicalLevels[nodeId] === undefined ? 0 : this.hierarchicalLevels[nodeId];
if (this.options.hierarchical.direction === 'UD' || this.options.hierarchical.direction === 'DU') {
node.y = this.options.hierarchical.levelSeparation * level;
node.options.fixed.y = true;
}
else {
node.x = this.options.hierarchical.levelSeparation * level;
node.options.fixed.x = true;
}
if (distribution[level] === undefined) {
distribution[level] = {};
}
distribution[level][nodeId] = node;
}
}
return distribution;
}
/**
* Get the hubsize from all remaining unlevelled nodes.
*
* @returns {number}
* @private
*/
_getHubSize() {
let hubSize = 0;
for (let nodeId in this.body.nodes) {
if (this.body.nodes.hasOwnProperty(nodeId)) {
let node = this.body.nodes[nodeId];
if (this.hierarchicalLevels[nodeId] === undefined) {
hubSize = node.edges.length < hubSize ? hubSize : node.edges.length;
}
}
}
return hubSize;
}
/**
* this function allocates nodes in levels based on the recursive branching from the largest hubs.
*
* @param hubsize
* @private
*/
_determineLevelsByHubsize() {
let hubSize = 1;
let levelDownstream = (nodeA, nodeB) => {
if (this.hierarchicalLevels[nodeB.id] === undefined) {
// set initial level
if (this.hierarchicalLevels[nodeA.id] === undefined) {
this.hierarchicalLevels[nodeA.id] = 0;
}
// set level
this.hierarchicalLevels[nodeB.id] = this.hierarchicalLevels[nodeA.id] + 1;
}
};
while (hubSize > 0) {
// determine hubs
hubSize = this._getHubSize();
if (hubSize === 0)
break;
for (let nodeId in this.body.nodes) {
if (this.body.nodes.hasOwnProperty(nodeId)) {
let node = this.body.nodes[nodeId];
if (node.edges.length === hubSize) {
this._crawlNetwork(levelDownstream,nodeId);
}
}
}
}
}
/**
* TODO: release feature
* @private
*/
_determineLevelsCustomCallback() {
let minLevel = 100000;
// TODO: this should come from options.
let customCallback = function(nodeA, nodeB, edge) {
};
let levelByDirection = (nodeA, nodeB, edge) => {
let levelA = this.hierarchicalLevels[nodeA.id];
// set initial level
if (levelA === undefined) {this.hierarchicalLevels[nodeA.id] = minLevel;}
let diff = customCallback(
NetworkUtil.cloneOptions(nodeA,'node'),
NetworkUtil.cloneOptions(nodeB,'node'),
NetworkUtil.cloneOptions(edge,'edge')
);
this.hierarchicalLevels[nodeB.id] = this.hierarchicalLevels[nodeA.id] + diff;
};
this._crawlNetwork(levelByDirection);
this._setMinLevelToZero();
}
/**
* this function allocates nodes in levels based on the direction of the edges
*
* @param hubsize
* @private
*/
_determineLevelsDirected() {
let minLevel = 10000;
let levelByDirection = (nodeA, nodeB, edge) => {
let levelA = this.hierarchicalLevels[nodeA.id];
// set initial level
if (levelA === undefined) {this.hierarchicalLevels[nodeA.id] = minLevel;}
if (edge.toId == nodeB.id) {
this.hierarchicalLevels[nodeB.id] = this.hierarchicalLevels[nodeA.id] + 1;
}
else {
this.hierarchicalLevels[nodeB.id] = this.hierarchicalLevels[nodeA.id] - 1;
}
};
this._crawlNetwork(levelByDirection);
this._setMinLevelToZero();
}
/**
* Small util method to set the minimum levels of the nodes to zero.
* @private
*/
_setMinLevelToZero() {
let minLevel = 1e9;
// get the minimum level
for (let nodeId in this.body.nodes) {
if (this.body.nodes.hasOwnProperty(nodeId)) {
minLevel = Math.min(this.hierarchicalLevels[nodeId], minLevel);
}
}
// subtract the minimum from the set so we have a range starting from 0
for (let nodeId in this.body.nodes) {
if (this.body.nodes.hasOwnProperty(nodeId)) {
this.hierarchicalLevels[nodeId] -= minLevel;
}
}
}
/**
* Update the bookkeeping of parent and child.
* @param parentNodeId
* @param childNodeId
* @private
*/
_generateMap() {
let fillInRelations = (parentNode, childNode) => {
if (this.hierarchicalLevels[childNode.id] > this.hierarchicalLevels[parentNode.id]) {
let parentNodeId = parentNode.id;
let childNodeId = childNode.id;
if (this.hierarchicalParents[parentNodeId] === undefined) {
this.hierarchicalParents[parentNodeId] = {children: [], amount: 0};
}
this.hierarchicalParents[parentNodeId].children.push(childNodeId);
if (this.hierarchicalChildren[childNodeId] === undefined) {
this.hierarchicalChildren[childNodeId] = {parents: [], amount: 0};
}
this.hierarchicalChildren[childNodeId].parents.push(parentNodeId);
}
};
this._crawlNetwork(fillInRelations);
}
/**
* Crawl over the entire network and use a callback on each node couple that is connected to eachother.
* @param callback | will receive nodeA nodeB and the connecting edge. A and B are unique.
* @param startingNodeId
* @private
*/
_crawlNetwork(callback = function() {}, startingNodeId) {
let progress = {};
let crawler = (node) => {
if (progress[node.id] === undefined) {
progress[node.id] = true;
let childNode;
for (let i = 0; i < node.edges.length; i++) {
if (node.edges[i].toId === node.id) {childNode = node.edges[i].from;}
else {childNode = node.edges[i].to;}
if (node.id !== childNode.id) {
callback(node, childNode, node.edges[i]);
crawler(childNode);
}
}
}
};
// we can crawl from a specific node or over all nodes.
if (startingNodeId === undefined) {
for (let i = 0; i < this.body.nodeIndices.length; i++) {
let node = this.body.nodes[this.body.nodeIndices[i]];
crawler(node);
}
}
else {
let node = this.body.nodes[startingNodeId];
if (node === undefined) {
console.error("Node not found:", startingNodeId);
return;
}
crawler(node);
}
}
/**
* This is a recursively called function to enumerate the branches from the largest hubs and place the nodes
* on a X position that ensures there will be no overlap.
*
* @param parentId
* @param parentLevel
* @private
*/
_placeBranchNodes(parentId, parentLevel) {
// if this is not a parent, cancel the placing. This can happen with multiple parents to one child.
if (this.hierarchicalParents[parentId] === undefined) {
return;
}
// get a list of childNodes
let childNodes = [];
for (let i = 0; i < this.hierarchicalParents[parentId].children.length; i++) {
childNodes.push(this.body.nodes[this.hierarchicalParents[parentId].children[i]]);
}
// use the positions to order the nodes.
this._sortNodeArray(childNodes);
// position the childNodes
for (let i = 0; i < childNodes.length; i++) {
let childNode = childNodes[i];
let childNodeLevel = this.hierarchicalLevels[childNode.id];
// check if the child node is below the parent node and if it has already been positioned.
if (childNodeLevel > parentLevel && this.positionedNodes[childNode.id] === undefined) {
// get the amount of space required for this node. If parent the width is based on the amount of children.
let pos;
// we get the X or Y values we need and store them in pos and previousPos. The get and set make sure we get X or Y
if (i === 0) {pos = this._getPositionForHierarchy(this.body.nodes[parentId]);}
else {pos = this._getPositionForHierarchy(childNodes[i-1]) + this.nodeSpacing;}
this._setPositionForHierarchy(childNode, pos, childNodeLevel);
// if overlap has been detected, we shift the branch
if (this.lastNodeOnLevel[childNodeLevel] !== undefined) {
let previousPos = this._getPositionForHierarchy(this.body.nodes[this.lastNodeOnLevel[childNodeLevel]]);
if (pos - previousPos < this.nodeSpacing) {
let diff = (previousPos + this.nodeSpacing) - pos;
let sharedParent = this._findCommonParent(this.lastNodeOnLevel[childNodeLevel], childNode.id);
this._shiftBlock(sharedParent.withChild, diff);
}
}
// store change in position.
this.lastNodeOnLevel[childNodeLevel] = childNode.id;
this.positionedNodes[childNode.id] = true;
this._placeBranchNodes(childNode.id, childNodeLevel);
}
else {
return
}
}
// center the parent nodes.
let minPos = 1e9;
let maxPos = -1e9;
for (let i = 0; i < childNodes.length; i++) {
let childNodeId = childNodes[i].id;
minPos = Math.min(minPos, this._getPositionForHierarchy(this.body.nodes[childNodeId]));
maxPos = Math.max(maxPos, this._getPositionForHierarchy(this.body.nodes[childNodeId]));
}
this._setPositionForHierarchy(this.body.nodes[parentId], 0.5 * (minPos + maxPos), parentLevel);
}
/**
* Shift a branch a certain distance
* @param parentId
* @param diff
* @private
*/
_shiftBlock(parentId, diff) {
if (this.options.hierarchical.direction === 'UD' || this.options.hierarchical.direction === 'DU') {
this.body.nodes[parentId].x += diff;
}
else {
this.body.nodes[parentId].y += diff;
}
if (this.hierarchicalParents[parentId] !== undefined) {
for (let i = 0; i < this.hierarchicalParents[parentId].children.length; i++) {
this._shiftBlock(this.hierarchicalParents[parentId].children[i], diff);
}
}
}
/**
* Find a common parent between branches.
* @param childA
* @param childB
* @returns {{foundParent, withChild}}
* @private
*/
_findCommonParent(childA,childB) {
let parents = {};
let iterateParents = (parents,child) => {
if (this.hierarchicalChildren[child] !== undefined) {
for (let i = 0; i < this.hierarchicalChildren[child].parents.length; i++) {
let parent = this.hierarchicalChildren[child].parents[i];
parents[parent] = true;
iterateParents(parents, parent)
}
}
};
let findParent = (parents, child) => {
if (this.hierarchicalChildren[child] !== undefined) {
for (let i = 0; i < this.hierarchicalChildren[child].parents.length; i++) {
let parent = this.hierarchicalChildren[child].parents[i];
if (parents[parent] !== undefined) {
return {foundParent:parent, withChild:child};
}
let branch = findParent(parents, parent);
if (branch.foundParent !== null) {
return branch;
}
}
}
return {foundParent:null, withChild:child};
};
iterateParents(parents, childA);
return findParent(parents, childB);
}
/**
* Abstract the getting of the position so we won't have to repeat the check for direction all the time
* @param node
* @param position
* @param level
* @private
*/
_setPositionForHierarchy(node, position, level) {
if (this.distributionOrdering[level] === undefined) {
this.distributionOrdering[level] = [];
this.distributionOrderingPresence[level] = {};
}
if (this.distributionOrderingPresence[level][node.id] === undefined) {
this.distributionOrdering[level].push(node);
}
this.distributionOrderingPresence[level][node.id] = true;
if (this.options.hierarchical.direction === 'UD' || this.options.hierarchical.direction === 'DU') {
node.x = position;
}
else {
node.y = position;
}
}
/**
* Abstract the getting of the position of a node so we do not have to repeat the direction check all the time.
* @param node
* @returns {number|*}
* @private
*/
_getPositionForHierarchy(node) {
if (this.options.hierarchical.direction === 'UD' || this.options.hierarchical.direction === 'DU') {
return node.x;
}
else {
return node.y;
}
}
/**
* Use the x or y value to sort the array, allowing users to specify order.
* @param nodeArray
* @private
*/
_sortNodeArray(nodeArray) {
if (nodeArray.length > 1) {
if (this.options.hierarchical.direction === 'UD' || this.options.hierarchical.direction === 'DU') {
nodeArray.sort(function (a, b) {
return a.x - b.x;
})
}
else {
nodeArray.sort(function (a, b) {
return a.y - b.y;
})
}
}
}
}
export default LayoutEngine;