springy/springy.js
2012-05-16 21:35:17 +10:00

552 lines
15 KiB
JavaScript

/**
* Springy v1.0.1
*
* Copyright (c) 2010 Dennis Hotson
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
var Graph = function() {
this.nodeSet = {};
this.nodes = [];
this.edges = [];
this.adjacency = {};
this.nextNodeId = 0;
this.nextEdgeId = 0;
this.eventListeners = [];
};
var Node = function(id, data) {
this.id = id;
this.data = typeof(data) !== 'undefined' ? data : {};
};
var Edge = function(id, source, target, data) {
this.id = id;
this.source = source;
this.target = target;
this.data = typeof(data) !== 'undefined' ? data : {};
};
Graph.prototype.addNode = function(node) {
if (typeof(this.nodeSet[node.id]) === 'undefined') {
this.nodes.push(node);
}
this.nodeSet[node.id] = node;
this.notify();
return node;
};
Graph.prototype.addEdge = function(edge) {
var exists = false;
this.edges.forEach(function(e) {
if (edge.id === e.id) { exists = true; }
});
if (!exists) {
this.edges.push(edge);
}
if (typeof(this.adjacency[edge.source.id]) === 'undefined') {
this.adjacency[edge.source.id] = {};
}
if (typeof(this.adjacency[edge.source.id][edge.target.id]) === 'undefined') {
this.adjacency[edge.source.id][edge.target.id] = [];
}
exists = false;
this.adjacency[edge.source.id][edge.target.id].forEach(function(e) {
if (edge.id === e.id) { exists = true; }
});
if (!exists) {
this.adjacency[edge.source.id][edge.target.id].push(edge);
}
this.notify();
return edge;
};
Graph.prototype.newNode = function(data) {
var node = new Node(this.nextNodeId++, data);
this.addNode(node);
return node;
};
Graph.prototype.newEdge = function(source, target, data) {
var edge = new Edge(this.nextEdgeId++, source, target, data);
this.addEdge(edge);
return edge;
};
// find the edges from node1 to node2
Graph.prototype.getEdges = function(node1, node2) {
if (typeof(this.adjacency[node1.id]) !== 'undefined'
&& typeof(this.adjacency[node1.id][node2.id]) !== 'undefined') {
return this.adjacency[node1.id][node2.id];
}
return [];
};
// remove a node and it's associated edges from the graph
Graph.prototype.removeNode = function(node) {
if (typeof(this.nodeSet[node.id]) !== 'undefined') {
delete this.nodeSet[node.id];
}
for (var i = this.nodes.length - 1; i >= 0; i--) {
if (this.nodes[i].id === node.id) {
this.nodes.splice(i, 1);
}
}
this.detachNode(node);
};
// removes edges associated with a given node
Graph.prototype.detachNode = function(node) {
var tmpEdges = this.edges.slice();
tmpEdges.forEach(function(e) {
if (e.source.id === node.id || e.target.id === node.id) {
this.removeEdge(e);
}
}, this);
this.notify();
};
// remove a node and it's associated edges from the graph
Graph.prototype.removeEdge = function(edge) {
for (var i = this.edges.length - 1; i >= 0; i--) {
if (this.edges[i].id === edge.id) {
this.edges.splice(i, 1);
}
}
for (var x in this.adjacency) {
for (var y in this.adjacency[x]) {
var edges = this.adjacency[x][y];
for (var j=edges.length - 1; j>=0; j--) {
if (this.adjacency[x][y][j].id === edge.id) {
this.adjacency[x][y].splice(j, 1);
}
}
}
}
this.notify();
};
/* Merge a list of nodes and edges into the current graph. eg.
var o = {
nodes: [
{id: 123, data: {type: 'user', userid: 123, displayname: 'aaa'}},
{id: 234, data: {type: 'user', userid: 234, displayname: 'bbb'}}
],
edges: [
{from: 0, to: 1, type: 'submitted_design', directed: true, data: {weight: }}
]
}
*/
Graph.prototype.merge = function(data) {
var nodes = [];
data.nodes.forEach(function(n) {
nodes.push(this.addNode(new Node(n.id, n.data)));
}, this);
data.edges.forEach(function(e) {
var from = nodes[e.from];
var to = nodes[e.to];
var id = (e.directed)
? (id = e.type + "-" + from.id + "-" + to.id)
: (from.id < to.id) // normalise id for non-directed edges
? e.type + "-" + from.id + "-" + to.id
: e.type + "-" + to.id + "-" + from.id;
var edge = this.addEdge(new Edge(id, from, to, e.data));
edge.data.type = e.type;
}, this);
};
Graph.prototype.filterNodes = function(fn) {
var tmpNodes = this.nodes.slice();
tmpNodes.forEach(function(n) {
if (!fn(n)) {
this.removeNode(n);
}
}, this);
};
Graph.prototype.filterEdges = function(fn) {
var tmpEdges = this.edges.slice();
tmpEdges.forEach(function(e) {
if (!fn(e)) {
this.removeEdge(e);
}
}, this);
};
Graph.prototype.addGraphListener = function(obj) {
this.eventListeners.push(obj);
};
Graph.prototype.notify = function() {
this.eventListeners.forEach(function(obj){
obj.graphChanged();
});
};
// -----------
var Layout = {};
Layout.ForceDirected = function(graph, stiffness, repulsion, damping) {
this.graph = graph;
this.stiffness = stiffness; // spring stiffness constant
this.repulsion = repulsion; // repulsion constant
this.damping = damping; // velocity damping factor
this.nodePoints = {}; // keep track of points associated with nodes
this.edgeSprings = {}; // keep track of springs associated with edges
};
Layout.ForceDirected.prototype.point = function(node) {
if (typeof(this.nodePoints[node.id]) === 'undefined') {
var mass = typeof(node.data.mass) !== 'undefined' ? node.data.mass : 1.0;
this.nodePoints[node.id] = new Layout.ForceDirected.Point(Vector.random(), mass);
}
return this.nodePoints[node.id];
};
Layout.ForceDirected.prototype.spring = function(edge) {
if (typeof(this.edgeSprings[edge.id]) === 'undefined') {
var length = typeof(edge.data.length) !== 'undefined' ? edge.data.length : 1.0;
var existingSpring = false;
var from = this.graph.getEdges(edge.source, edge.target);
from.forEach(function(e) {
if (existingSpring === false && typeof(this.edgeSprings[e.id]) !== 'undefined') {
existingSpring = this.edgeSprings[e.id];
}
}, this);
if (existingSpring !== false) {
return new Layout.ForceDirected.Spring(existingSpring.point1, existingSpring.point2, 0.0, 0.0);
}
var to = this.graph.getEdges(edge.target, edge.source);
from.forEach(function(e){
if (existingSpring === false && typeof(this.edgeSprings[e.id]) !== 'undefined') {
existingSpring = this.edgeSprings[e.id];
}
}, this);
if (existingSpring !== false) {
return new Layout.ForceDirected.Spring(existingSpring.point2, existingSpring.point1, 0.0, 0.0);
}
this.edgeSprings[edge.id] = new Layout.ForceDirected.Spring(
this.point(edge.source), this.point(edge.target), length, this.stiffness
);
}
return this.edgeSprings[edge.id];
};
// callback should accept two arguments: Node, Point
Layout.ForceDirected.prototype.eachNode = function(callback) {
var t = this;
this.graph.nodes.forEach(function(n){
callback.call(t, n, t.point(n));
});
};
// callback should accept two arguments: Edge, Spring
Layout.ForceDirected.prototype.eachEdge = function(callback) {
var t = this;
this.graph.edges.forEach(function(e){
callback.call(t, e, t.spring(e));
});
};
// callback should accept one argument: Spring
Layout.ForceDirected.prototype.eachSpring = function(callback) {
var t = this;
this.graph.edges.forEach(function(e){
callback.call(t, t.spring(e));
});
};
// Physics stuff
Layout.ForceDirected.prototype.applyCoulombsLaw = function() {
this.eachNode(function(n1, point1) {
this.eachNode(function(n2, point2) {
if (point1 !== point2)
{
var d = point1.p.subtract(point2.p);
var distance = d.magnitude() + 0.1; // avoid massive forces at small distances (and divide by zero)
var direction = d.normalise();
// apply force to each end point
point1.applyForce(direction.multiply(this.repulsion).divide(distance * distance * 0.5));
point2.applyForce(direction.multiply(this.repulsion).divide(distance * distance * -0.5));
}
});
});
};
Layout.ForceDirected.prototype.applyHookesLaw = function() {
this.eachSpring(function(spring){
var d = spring.point2.p.subtract(spring.point1.p); // the direction of the spring
var displacement = spring.length - d.magnitude();
var direction = d.normalise();
// apply force to each end point
spring.point1.applyForce(direction.multiply(spring.k * displacement * -0.5));
spring.point2.applyForce(direction.multiply(spring.k * displacement * 0.5));
});
};
Layout.ForceDirected.prototype.attractToCentre = function() {
this.eachNode(function(node, point) {
var direction = point.p.multiply(-1.0);
point.applyForce(direction.multiply(this.repulsion / 50.0));
});
};
Layout.ForceDirected.prototype.updateVelocity = function(timestep) {
this.eachNode(function(node, point) {
// Is this, along with updatePosition below, the only places that your
// integration code exist?
point.v = point.v.add(point.a.multiply(timestep)).multiply(this.damping);
point.a = new Vector(0,0);
});
};
Layout.ForceDirected.prototype.updatePosition = function(timestep) {
this.eachNode(function(node, point) {
// Same question as above; along with updateVelocity, is this all of
// your integration code?
point.p = point.p.add(point.v.multiply(timestep));
});
};
// Calculate the total kinetic energy of the system
Layout.ForceDirected.prototype.totalEnergy = function(timestep) {
var energy = 0.0;
this.eachNode(function(node, point) {
var speed = point.v.magnitude();
energy += 0.5 * point.m * speed * speed;
});
return energy;
};
var __bind = function(fn, me){ return function(){ return fn.apply(me, arguments); }; }; // stolen from coffeescript, thanks jashkenas! ;-)
Layout.requestAnimationFrame = __bind(window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function(callback, element) {
window.setTimeout(callback, 10);
}, window);
// start simulation
Layout.ForceDirected.prototype.start = function(interval, render, done) {
var t = this;
if (this._started) return;
this._started = true;
Layout.requestAnimationFrame(function step() {
t.applyCoulombsLaw();
t.applyHookesLaw();
t.attractToCentre();
t.updateVelocity(0.03);
t.updatePosition(0.03);
if (typeof(render) !== 'undefined')
render();
// stop simulation when energy of the system goes below a threshold
if (t.totalEnergy() < 0.01) {
t._started = false;
if (typeof(done) !== 'undefined') { done(); }
} else {
Layout.requestAnimationFrame(step);
}
});
};
// Find the nearest point to a particular position
Layout.ForceDirected.prototype.nearest = function(pos) {
var min = {node: null, point: null, distance: null};
var t = this;
this.graph.nodes.forEach(function(n){
var point = t.point(n);
var distance = point.p.subtract(pos).magnitude();
if (min.distance === null || distance < min.distance) {
min = {node: n, point: point, distance: distance};
}
});
return min;
};
// returns [bottomleft, topright]
Layout.ForceDirected.prototype.getBoundingBox = function() {
var bottomleft = new Vector(-2,-2);
var topright = new Vector(2,2);
this.eachNode(function(n, point) {
if (point.p.x < bottomleft.x) {
bottomleft.x = point.p.x;
}
if (point.p.y < bottomleft.y) {
bottomleft.y = point.p.y;
}
if (point.p.x > topright.x) {
topright.x = point.p.x;
}
if (point.p.y > topright.y) {
topright.y = point.p.y;
}
});
var padding = topright.subtract(bottomleft).multiply(0.07); // ~5% padding
return {bottomleft: bottomleft.subtract(padding), topright: topright.add(padding)};
};
// Vector
Vector = function(x, y) {
this.x = x;
this.y = y;
};
Vector.random = function() {
return new Vector(10.0 * (Math.random() - 0.5), 10.0 * (Math.random() - 0.5));
};
Vector.prototype.add = function(v2) {
return new Vector(this.x + v2.x, this.y + v2.y);
};
Vector.prototype.subtract = function(v2) {
return new Vector(this.x - v2.x, this.y - v2.y);
};
Vector.prototype.multiply = function(n) {
return new Vector(this.x * n, this.y * n);
};
Vector.prototype.divide = function(n) {
return new Vector((this.x / n) || 0, (this.y / n) || 0); // Avoid divide by zero errors..
};
Vector.prototype.magnitude = function() {
return Math.sqrt(this.x*this.x + this.y*this.y);
};
Vector.prototype.normal = function() {
return new Vector(-this.y, this.x);
};
Vector.prototype.normalise = function() {
return this.divide(this.magnitude());
};
// Point
Layout.ForceDirected.Point = function(position, mass) {
this.p = position; // position
this.m = mass; // mass
this.v = new Vector(0, 0); // velocity
this.a = new Vector(0, 0); // acceleration
};
Layout.ForceDirected.Point.prototype.applyForce = function(force) {
this.a = this.a.add(force.divide(this.m));
};
// Spring
Layout.ForceDirected.Spring = function(point1, point2, length, k) {
this.point1 = point1;
this.point2 = point2;
this.length = length; // spring length at rest
this.k = k; // spring constant (See Hooke's law) .. how stiff the spring is
};
// Layout.ForceDirected.Spring.prototype.distanceToPoint = function(point)
// {
// // hardcore vector arithmetic.. ohh yeah!
// // .. see http://stackoverflow.com/questions/849211/shortest-distance-between-a-point-and-a-line-segment/865080#865080
// var n = this.point2.p.subtract(this.point1.p).normalise().normal();
// var ac = point.p.subtract(this.point1.p);
// return Math.abs(ac.x * n.x + ac.y * n.y);
// };
// Renderer handles the layout rendering loop
function Renderer(interval, layout, clear, drawEdge, drawNode) {
this.interval = interval;
this.layout = layout;
this.clear = clear;
this.drawEdge = drawEdge;
this.drawNode = drawNode;
this.layout.graph.addGraphListener(this);
}
Renderer.prototype.graphChanged = function(e) {
this.start();
};
Renderer.prototype.start = function() {
var t = this;
this.layout.start(50, function render() {
t.clear();
t.layout.eachEdge(function(edge, spring) {
t.drawEdge(edge, spring.point1.p, spring.point2.p);
});
t.layout.eachNode(function(node, point) {
t.drawNode(node, point.p);
});
});
};