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larsvers

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split, unite and keep in bounds

<!doctype html>
<html lang="en">
<head>
	<meta charset="utf-8">
	<title>winter force</title>
	<meta name="viewport" content="width=device-width, initial-scale=1">
 	<script src="https://d3js.org/d3.v4.js"></script>
	<link rel="stylesheet" type="text/css" href="force.css">

html, body {
			margin: 0;
			padding: 0;
			border: 0;
			font-family: Arial;
			font-size: 100%;
			vertical-align: baseline;
			height: 100%;
			box-sizing: border-box;
		}

*, *:before, *:after{
			box-sizing: inherit;	
		}

a:link, a:visited, a:hover, a:active {
			color: #000;
		}

/* === Canvas === */

canvas {
			border: 1px solid #ccc;
			margin: 50px;
			margin-bottom: 10px;
		}

button#split {
			margin-left:  50px;
		}

</style>

</head>
<body>

<div id="container"></div>
<button id="split">Split</button>
<button id="unite">Unite</button>
<button id="bounded">Keep in bounds</button>

// === Globals === //

var width = 500, height = 250;
var simulation, bounded = false;

// === Set up canvas === //

var canvas = d3.select('#container').append('canvas').attr('width', width).attr('height', height);

var context = canvas.node().getContext('2d');

// === Start the simulation === //

getSimulationData();

// === Get simulation data === //

function getSimulationData() {

var nodes = [];

d3.range(400).forEach(function(el, i) {

var obj = {};
		obj.cluster = 0;
		obj.radius = 5;
		obj.colour = '#9CCFE5';
		obj.x = width/2 + (Math.random() - 10); // slightly left-skewed position
		obj.y = height/2 + (Math.random());

nodes.push(obj);

}); // get men nodes

d3.range(100).forEach(function(el, i) {

var obj = {};
		obj.cluster = 1;
		obj.radius = 5;
    obj.colour = '#9FE789';
		obj.x = width/2 + (Math.random() + 10); // slightly right-skewed position
		obj.y = height/2 + (Math.random());

nodes.push(obj);

}); // get women nodes

initSimulation(nodes); // kick off simulation

} // getSimulationData()

// === Set up simulation params === //

function initSimulation(nodes) {

simulation = d3.forceSimulation(nodes)
		.alpha(.02)
		.force('charge', d3.forceManyBody().strength(-30))
		.force('xPos', d3.forceX(width/2).strength(1))
		.force('yPos', d3.forceY(height/2).strength(1));

simulation.on('tick', ticked);

function ticked() {

context.clearRect(0, 0, width, height);
		context.save();

nodes.forEach(drawNode);

context.restore()

} // ticked()

function drawNode(d) {

if (bounded) {
			d.x = Math.max(d.radius, Math.min(width - d.radius, d.x));
			d.y = Math.max(d.radius, Math.min(height - d.radius, d.y));			
		}

context.beginPath();
		context.moveTo(d.x + d.radius, d.y);
		context.arc(d.x, d.y, d.radius, 0, 2 * Math.PI);
		context.fillStyle = d.colour;
		context.fill();

} // drawNode()

} // Set up the simulation

// === Button handler === //

d3.select('button#split').on('mousedown', function(d) {

simulation.stop();

simulation
			.force('charge', d3.forceManyBody().strength(-5))
			.force('xPos', d3.forceX(function(d) { return d.cluster === 0 ? width * 0.3 : width * 0.7; }) )
			.force('yPos', d3.forceY(height/2));
			
		simulation.alpha(0.5);

simulation.restart();

}); // button listener/handler

d3.select('button#unite').on('mousedown', function(d) {

simulation.stop();

simulation
			.force('charge', d3.forceManyBody().strength(-5))
			.force('xPos', d3.forceX(function(d) { return d.cluster === 0 ? width * 0.6 : width * 0.4; }) )
			.force('yPos', d3.forceY(height/2))
    	.force('collision', d3.forceCollide(5));
			
		simulation.alpha(0.5);

simulation.restart();

}); // button listener/handler

d3.select('button#bounded').on('mousedown', function(d) {

simulation.stop();

bounded = bounded === false ? true : false;

simulation.alpha(0.5);

simulation.restart();

}); // button listener/handler

</script>

</body>
</html>

Modified http://d3js.org/d3.v4.js to a secure url

https://d3js.org/d3.v4.js