vis.js is a dynamic, browser-based visualization library
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'use strict'
let util = require('../../util');
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.hierarchicalLevels = {};
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 seperation 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.adaptAllOptions(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;
}
adaptAllOptions(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 KamadaKawai 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 KamadaKawai 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 = 200;
let levels = 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) {
levels += 1;
let before = this.body.nodeIndices.length;
// if there are many nodes we do a hubsize cluster
if (levels % 3 === 0) {
this.body.modules.clustering.clusterBridges();
}
else {
this.body.modules.clustering.clusterOutliers();
}
let after = this.body.nodeIndices.length;
if ((before == after && levels % 3 !== 0) || levels > MAX_LEVELS) {
this._declusterAll();
console.info("This network could not be positioned by this version of the improved layout algorithm.");
return;
}
}
// 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);
// uncluster all clusters
this._declusterAll();
// reposition all bezier nodes.
this.body.emitter.emit("_repositionBezierNodes");
}
}
}
_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 {
// setup the system to use hierarchical method.
//this._changeConstants();
// 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' || 'direction') {
this._determineLevelsDirected();
}
}
// check the distribution of the nodes per level.
let distribution = this._getDistribution();
// place the nodes on the canvas.
this._placeNodesByHierarchy(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) {
let nodeId, node;
this.positionedNodes = {};
// start placing all the level 0 nodes first. Then recursively position their branches.
for (let level in distribution) {
if (distribution.hasOwnProperty(level)) {
for (nodeId in distribution[level].nodes) {
if (distribution[level].nodes.hasOwnProperty(nodeId)) {
node = distribution[level].nodes[nodeId];
if (this.options.hierarchical.direction === 'UD' || this.options.hierarchical.direction === 'DU') {
if (node.x === undefined) {node.x = distribution[level].distance;}
distribution[level].distance = node.x + this.nodeSpacing;
}
else {
if (node.y === undefined) {node.y = distribution[level].distance;}
distribution[level].distance = node.y + this.nodeSpacing;
}
this.positionedNodes[nodeId] = true;
this._placeBranchNodes(node.edges,node.id,distribution,level);
}
}
}
}
}
/**
* 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] = {amount: 0, nodes: {}, distance: 0};
}
distribution[level].amount += 1;
distribution[level].nodes[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 nodeId, node;
let hubSize = 1;
while (hubSize > 0) {
// determine hubs
hubSize = this._getHubSize();
if (hubSize === 0)
break;
for (nodeId in this.body.nodes) {
if (this.body.nodes.hasOwnProperty(nodeId)) {
node = this.body.nodes[nodeId];
if (node.edges.length === hubSize) {
this._setLevelByHubsize(0, node);
}
}
}
}
}
/**
* this function is called recursively to enumerate the barnches of the largest hubs and give each node a level.
*
* @param level
* @param edges
* @param parentId
* @private
*/
_setLevelByHubsize(level, node) {
if (this.hierarchicalLevels[node.id] !== undefined)
return;
let childNode;
this.hierarchicalLevels[node.id] = level;
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;
}
this._setLevelByHubsize(level + 1, childNode);
}
}
/**
* this function allocates nodes in levels based on the direction of the edges
*
* @param hubsize
* @private
*/
_determineLevelsDirected() {
let nodeId, node;
let minLevel = 10000;
// set first node to source
for (nodeId in this.body.nodes) {
if (this.body.nodes.hasOwnProperty(nodeId)) {
node = this.body.nodes[nodeId];
this._setLevelDirected(minLevel,node);
}
}
// get the minimum level
for (nodeId in this.body.nodes) {
if (this.body.nodes.hasOwnProperty(nodeId)) {
minLevel = this.hierarchicalLevels[nodeId] < minLevel ? this.hierarchicalLevels[nodeId] : minLevel;
}
}
// subtract the minimum from the set so we have a range starting from 0
for (nodeId in this.body.nodes) {
if (this.body.nodes.hasOwnProperty(nodeId)) {
this.hierarchicalLevels[nodeId] -= minLevel;
}
}
}
/**
* this function is called recursively to enumerate the branched of the first node and give each node a level based on edge direction
*
* @param level
* @param edges
* @param parentId
* @private
*/
_setLevelDirected(level, node) {
if (this.hierarchicalLevels[node.id] !== undefined)
return;
let childNode;
this.hierarchicalLevels[node.id] = level;
for (let i = 0; i < node.edges.length; i++) {
if (node.edges[i].toId === node.id) {
childNode = node.edges[i].from;
this._setLevelDirected(level - 1, childNode);
}
else {
childNode = node.edges[i].to;
this._setLevelDirected(level + 1, childNode);
}
}
}
/**
* 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 edges
* @param parentId
* @param distribution
* @param parentLevel
* @private
*/
_placeBranchNodes(edges, parentId, distribution, parentLevel) {
for (let i = 0; i < edges.length; i++) {
let childNode = undefined;
let parentNode = undefined;
if (edges[i].toId === parentId) {
childNode = edges[i].from;
parentNode = edges[i].to;
}
else {
childNode = edges[i].to;
parentNode = edges[i].from;
}
let childNodeLevel = this.hierarchicalLevels[childNode.id];
if (this.positionedNodes[childNode.id] === undefined) {
// if a node is conneceted to another node on the same level (or higher (means lower level))!, this is not handled here.
if (childNodeLevel > parentLevel) {
if (this.options.hierarchical.direction === 'UD' || this.options.hierarchical.direction === 'DU') {
if (childNode.x === undefined) {
childNode.x = Math.max(distribution[childNodeLevel].distance, parentNode.x);
}
distribution[childNodeLevel].distance = childNode.x + this.nodeSpacing;
this.positionedNodes[childNode.id] = true;
}
else {
if (childNode.y === undefined) {
childNode.y = Math.max(distribution[childNodeLevel].distance, parentNode.y)
}
distribution[childNodeLevel].distance = childNode.y + this.nodeSpacing;
}
this.positionedNodes[childNode.id] = true;
if (childNode.edges.length > 1) {
this._placeBranchNodes(childNode.edges, childNode.id, distribution, childNodeLevel);
}
}
}
}
}
}
export default LayoutEngine;