d3-force-cluster + d3-force-attract II

Example illustrating the use of both d3-force-cluster and d3-force-attract, with a dynamic attract target.

<!DOCTYPE html>
<html>
  <head>
    <title>d3-force-cluster and d3-force-attract</title>
  </head>

var width = 960,
    height = 500,
    padding = 1.5, // separation between same-color nodes
    clusterPadding = 6, // separation between different-color nodes
    maxRadius = 12;

var n = 200, // total number of nodes
    m = 10; // number of distinct clusters

var color = d3.scaleSequential(d3.interpolateRainbow)
    .domain(d3.range(m));

// The largest node for each cluster.
var clusters = new Array(m);

var nodes = d3.range(n).map(function () {
  var i = Math.floor(Math.random() * m),
      r = Math.sqrt((i + 1) / m * -Math.log(Math.random())) * maxRadius,
      d = {
        cluster: i,
        radius: r,
        x: Math.cos(i / m * 2 * Math.PI) * 200 + width / 2 + Math.random(),
        y: Math.sin(i / m * 2 * Math.PI) * 200 + height / 2 + Math.random()
      };
  if (!clusters[i] || (r > clusters[i].radius)) clusters[i] = d;
  return d;
});

var maxRad = d3.max(nodes, function (d) { return d.radius; }),
  maxStrength = 0.25;
var simulation = d3.forceSimulation()
  // pull toward mouse (see 'mousemove' handler below)
  .force('attract', d3.forceAttract()
    .target([width/2, height/2])
    .strength(function (d) { return Math.pow((d.radius / maxRad) * maxStrength, 2); }))

// cluster by section
  .force('cluster', d3.forceCluster()
    .centers(function (d) { return clusters[d.cluster]; })
    .strength(0.75)
    .centerInertia(0.1))

// apply collision with padding
  .force('collide', d3.forceCollide(function (d) { return d.radius + padding; })
    .strength(0))

.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')
    .style('fill', function (d) { return color(d.cluster/10); })
    .call(d3.drag()
      .on('start', dragstarted)
      .on('drag', dragged)
      .on('end', dragended)
    );

function dragstarted (d) {
  if (!d3.event.active) simulation.alphaTarget(0.3).restart();
  d.fx = d.x;
  d.fy = d.y;
}

function dragged (d) {
  d.fx = d3.event.x;
  d.fy = d3.event.y;
}

function dragended (d) {
  if (!d3.event.active) simulation.alphaTarget(0);
  d.fx = null;
  d.fy = null;
}

svg.on('mousemove', function () {
    simulation.force('attract').target(d3.mouse(this));
    simulation
      .alphaTarget(0.3)
      .restart();
  });
  
// ramp up collision strength to provide smooth transition
var transitionTime = 3000;
var t = d3.timer(function (elapsed) {
  var dt = elapsed / transitionTime;
  simulation.force('collide').strength(Math.pow(dt, 2) * 0.7);
  if (dt >= 1.0) t.stop();
});
  
function layoutTick (e) {
  node
    .attr('cx', function (d) { return d.x; })
    .attr('cy', function (d) { return d.y; })
    .attr('r', function (d) { return d.radius; });
}

</script>
  </body>
</html>

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

https://unpkg.com/d3-force-attract@latest

https://unpkg.com/d3-force-cluster@latest