Using Arbor/ RGraph JS libaries for Data Visualisation

EPSRC – Data Visualisation
Proof of Concept

Alex Hardman

Topics
• Node Graph (bouncing balls)
– (Quick) Demo
– Libraries
– Frontend / AJAX
• Details Graphs (bar charts etc)
– (Quick) Demo
– Libraries
– Frontend / AJAX

Libraries
• Node Graph  arborjs.org

• Graphs  rgraph.net

HTML5 + Canvas

Node Graph
• Uses Canvas (via the HTML5 getContext()
object.
• The getContext("2d") object has methods to
draw lines, boxes, circles, and more.
• Uses the Arbor js framework to store nodes
and edges and handle updating their
coordinates as the simulation progresses.

Node Graph - Creation
arbor.ParticleSystem()

• Parameters
– Repulsion (the force repelling nodes from each other)
– Stiffness (600 the rigidity of the edges)
– Friction (the amount of damping in the system)
– Gravity (an additional force attracting nodes to the origin)
– Fps (frames per second)
– Dt (timestep to use for stepping the simulation)
– Precision (accuracy vs. speed in force calculations
(zero is fast but jittery, one is smooth but cpu-intensive)

(stored in web.config passed to the view)

Feeding the graph
• Three calls to the server for graph data

loadInitialData

loadChildNodes

search

Feed the graph… “NodeGraphDTO”
• JSON from the server  “NodeGraphDTO”

Feed the graph… “NodeGraphDTO”
• Lists of :

Entities Relationships

Feed the graph… API
foreach(grant in Grants){
If (showGrants()) {
ParticleSystem.addNode(
Id,
{data we define such as
size, colour, label text
etc })
}
}
… Do for each type in NodeGraphDTO

Feed the graph… API
if(showPeople() && showGrants(){
foreach (rel in grantPersons) {
get the grant
get the person
ParticleSystem.addEdge(
grantId
personId
}
}

Node Graph – API Callbacks
• redraw()  Gets called repeatedly for each
frame
• We handle callbacks for:
– particleSystem.eachEdge(edge, pt1 pt2)
• Draw a gradient line between pt1 and pt2
– particleSystem.eachNode(node, pt)
• Work out what type of node we have
• Draw it out accordingly (Shape? ,Text? Size? Colour?)

Node Graph – API Callbacks
• initMouseHandling
– Moved  used to determine whether to display
hover text
– Clicked
– Dragged
– Dropped  determine whether to load child
nodes and quick details

JS – (as DRY as possible?)
$(document).ready(function () {
//Instantiate control objects
_restoreManager = new RestoreManager();
_state = new SystemState();
_aData = new DataHandler();
_controlsManager = new ControlsManager();
_nodeController = new NodeController();

//Initialise controls
_controlsManager.initialiseControls();

//Load initial data
_aData.loadInitialData();
});

General Usage
//Define object function ‘ControlsManager’
function ControlsManager() {
var self = this;
//Fix context of ‘this’ to the object
function

self.aPublicFunction = function(param) {
//I’m public
}
function aPrivateFunction (){
I’m private//
}
}

ControlsManager
//Define controls once as private
var showGrantsChk =
$("input:checkbox[id=ShowGran
ts]");

var showOutcomesChk =
$("input:checkbox[id=ShowOutc
omes]");

etc…

ControlsManager
//access them via public functions

self.initialiseControls =
function () {
…on(‘click’,…) etc.
}

self.clearDetails =
function() {…}

DataHandler
self.saveNodeGraphData(data) {
//Stores NodeGraphDTO object
//from server
}

self.childData = [];
//can contain child DataHandler(s)
//retrieved when clicking on nodes

self.addChildData(childDataHandler)

DataHandler
//Contains ajax functionilty for
//graph data.

loadInitialData()
//called on document ready

loadChildNodes()
//called after clicking on a node

NodeController
function initSystem() {
var sys =
arbor.ParticleSystem(..);
}

self.throttle()
self.unthrottle()

NodeController
self.doGraphObjects() {
buildThemes();
buildPeople();
//and all other nodes
buildPeopleToGrantEdges();
//and all other edges

for (var i = 0; i <
_aData.childData.length; i++) {
var childDataHandler =
_aData.childData[i];
self.doChildObjects
(childDataHandler);
}
}

NodeController - buildPeople
self.buildPeople() {
if (_state.showPeople()){
for(each person in
_aData.People){
addPersonNode(person)
sys.addEdge(…)
}
}
}

NodeController - addPersonNode
addPersonNode(person){
if (!nodeExists(person.Id)){
sys.addNode(
person.Id,
{
color:pColor,
display:person.Id,
size: nodeSize,
type: person.Type,
nodeType:labelNodeType,
showLabel:true
}
);
}
}

NodeController -
buildPeopleToGrantEdges
buildPeopleToGrantEdges () {
if (_state.showPeople() && _state.showGrants()) {
for (var i = 0; i <
_aData.peopleToGrants.length; i++) {
var pg = _aData.peopleToGrants[i];
var personNode = sys.getNode(pg.PersonId);
var grantNode = sys.getNode(pg.GrantId);
if (personNode !=undefined && grantNode !=
undefined) {
sys.addEdge(pg.PersonId, pg.GrantId,
{ color: edgeColour });
}

}
}
};

NodeControler - doChildObjects
self.doChildObjects = function(cData){
var parent = sys.getNode
(cData.rootData.Id);
//If the parent is null it is not
//a child object so do nothing
if (parent != undefined) {
addChildPeopleNodes(parent,
cData.peopleData);
//And all the other types
//(grants…, research areas…)
}
};

NodeController -
addCildPeopleNodes
function addChildPeopleNodes(parentNode, peopleDataArr) {
if (_state.showPeople()) {
for (var i = 0; i < peopleDataArr.length; i++) {
var person = peopleDataArr[i];
//If the node is root it ain’t a child!
if (!_state.isCurrentRoot(person.Id)) {
var exisitng = sys.getNode(person.Id);
if (exisitng == undefined) {
addPersonNode(person);
_aData.addNodeId(person.Id);
}
sys.addEdge(
parentNode.data.display,
person.Id, { color: edgeColour });
}
}
}
}

RestoreManager
//initialises the reset storage
//in local storage

function initResetStorage(){
localStorage.resetData = "";
}

RestoreManager
self.addRestorePoint = function (data) {
if (localStorage.resetData != "") {
var resetArr = JSON.parse
(localStorage.resetData);
resetArr.push(data);
localStorage.resetData =
JSON.stringify (resetArr);
}
else {
JSON.stringify
(new Array(data));
}
};

RestoreManager
self.getLastRestoreData = function () {
var resetData =
JSON.parse (localStorage.resetData);
if (resetData.length > 0) {
if (resetData.length == 1) {
return resetData[0];
}
var l = resetData.length;
var data = resetData[l - 2];
resetData.pop();
JSON.stringify (resetData);
return data;
}
return null;
};

Drawing out the nodes - Renderer

arborgraph.js
Line 1172

Using Arbor/ RGraph JS libaries for Data Visualisation

Details.js - ControlsManager
self.doResearchAreaGraph = function () {
var canvas = getCanvas();
var ctx = canvas.getContext('2d');
ctx.clearRect
(0, 0, canvas.width, canvas.height);
if(_state.selectedGraphType() == "Bar Chart"){
graph = new RGraph.Bar('graphCanvas',
_dataManager.raData.GraphValues);
graph.Set('chart.background.barcolor1',
'white');
graph.Set('chart.background.barcolor2',
'white');
graph.Set('chart.labels',
_dataManager.raData.Themes);
}
};

Using Arbor/ RGraph JS libaries for Data Visualisation

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