<!DOCTYPE html>
<html>
<head>
<title>d3-force-attract: mouse attract II</title>
</head>
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://unpkg.com/d3-force-attract@latest"></script>
<script>
var width = 960,
height = 500,
radius = 10;
var nodes = d3.range(50).map(function (d) {
return {
x: width * Math.random(),
y: height * Math.random(),
r: radius,
inertia: 0.05 + 0.15 * Math.random()
};
});
// set up attract force to pull nodes toward mouse location.
// set attract strength per node, to prevent nodes from bunching up
// (and to demonstrate per-node attract parameters).
var simulation = d3.forceSimulation()
.force('attract', d3.forceAttract()
.target([width / 2, height / 2])
.strength(function (d) { return d.inertia; }))
.force('collide', d3.forceCollide(function (d) { return d.r; }))
.on('tick', layoutTick)
.nodes(nodes);
var svg = d3.select('body').append('svg')
.attr('width', width)
.attr('height', height);
var node = svg.selectAll('circle')
.data(nodes)
.enter().append('circle')
.attr('cx', function (d) { return d.x; })
.attr('cy', function (d) { return d.y; })
.attr('r', function (d) { return d.r; });
svg.on('mousemove', function () {
simulation.force('attract').target(d3.mouse(this));
simulation
.alphaTarget(0.3)
.restart();
});
function layoutTick (e) {
node
.attr('cx', function (d) { return d.x; })
.attr('cy', function (d) { return d.y; });
}
</script>
</body>
</html>