Bilevel Partition

Click on any arc to zoom in. Click in the center to zoom out.

A sunburst is similar to a treemap, except it uses a radial layout. The root node of the tree is at the center, with leaves on the circumference. The area (or angle, depending on implementation) of each arc corresponds to its value. Sunburst design by John Stasko. Data courtesy Jeff Heer.

<!DOCTYPE html>
<meta charset="utf-8">
<style>

circle,
path {
  cursor: pointer;
}

circle {
  fill: none;
  pointer-events: all;
}

</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>

var margin = {top: 350, right: 480, bottom: 350, left: 480},
    radius = Math.min(margin.top, margin.right, margin.bottom, margin.left) - 10;

var hue = d3.scale.category10();

var luminance = d3.scale.sqrt()
    .domain([0, 1e6])
    .clamp(true)
    .range([90, 20]);

var svg = d3.select("body").append("svg")
    .attr("width", margin.left + margin.right)
    .attr("height", margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var partition = d3.layout.partition()
    .sort(function(a, b) { return d3.ascending(a.name, b.name); })
    .size([2 * Math.PI, radius]);

d3.json("flare.json", function(error, root) {
  if (error) throw error;

// Compute the initial layout on the entire tree to sum sizes.
  // Also compute the full name and fill color for each node,
  // and stash the children so they can be restored as we descend.
  partition
      .value(function(d) { return d.size; })
      .nodes(root)
      .forEach(function(d) {
        d._children = d.children;
        d.sum = d.value;
        d.key = key(d);
        d.fill = fill(d);
      });

// Now redefine the value function to use the previously-computed sum.
  partition
      .children(function(d, depth) { return depth < 2 ? d._children : null; })
      .value(function(d) { return d.sum; });

var center = svg.append("circle")
      .attr("r", radius / 3)
      .on("click", zoomOut);

center.append("title")
      .text("zoom out");

var path = svg.selectAll("path")
      .data(partition.nodes(root).slice(1))
    .enter().append("path")
      .attr("d", arc)
      .style("fill", function(d) { return d.fill; })
      .each(function(d) { this._current = updateArc(d); })
      .on("click", zoomIn);

function zoomIn(p) {
    if (p.depth > 1) p = p.parent;
    if (!p.children) return;
    zoom(p, p);
  }

function zoomOut(p) {
    if (!p.parent) return;
    zoom(p.parent, p);
  }

// Zoom to the specified new root.
  function zoom(root, p) {
    if (document.documentElement.__transition__) return;

// Rescale outside angles to match the new layout.
    var enterArc,
        exitArc,
        outsideAngle = d3.scale.linear().domain([0, 2 * Math.PI]);

function insideArc(d) {
      return p.key > d.key
          ? {depth: d.depth - 1, x: 0, dx: 0} : p.key < d.key
          ? {depth: d.depth - 1, x: 2 * Math.PI, dx: 0}
          : {depth: 0, x: 0, dx: 2 * Math.PI};
    }

function outsideArc(d) {
      return {depth: d.depth + 1, x: outsideAngle(d.x), dx: outsideAngle(d.x + d.dx) - outsideAngle(d.x)};
    }

center.datum(root);

// When zooming in, arcs enter from the outside and exit to the inside.
    // Entering outside arcs start from the old layout.
    if (root === p) enterArc = outsideArc, exitArc = insideArc, outsideAngle.range([p.x, p.x + p.dx]);

path = path.data(partition.nodes(root).slice(1), function(d) { return d.key; });

// When zooming out, arcs enter from the inside and exit to the outside.
    // Exiting outside arcs transition to the new layout.
    if (root !== p) enterArc = insideArc, exitArc = outsideArc, outsideAngle.range([p.x, p.x + p.dx]);

d3.transition().duration(d3.event.altKey ? 7500 : 750).each(function() {
      path.exit().transition()
          .style("fill-opacity", function(d) { return d.depth === 1 + (root === p) ? 1 : 0; })
          .attrTween("d", function(d) { return arcTween.call(this, exitArc(d)); })
          .remove();

path.enter().append("path")
          .style("fill-opacity", function(d) { return d.depth === 2 - (root === p) ? 1 : 0; })
          .style("fill", function(d) { return d.fill; })
          .on("click", zoomIn)
          .each(function(d) { this._current = enterArc(d); });

path.transition()
          .style("fill-opacity", 1)
          .attrTween("d", function(d) { return arcTween.call(this, updateArc(d)); });
    });
  }
});

function key(d) {
  var k = [], p = d;
  while (p.depth) k.push(p.name), p = p.parent;
  return k.reverse().join(".");
}

function fill(d) {
  var p = d;
  while (p.depth > 1) p = p.parent;
  var c = d3.lab(hue(p.name));
  c.l = luminance(d.sum);
  return c;
}

function arcTween(b) {
  var i = d3.interpolate(this._current, b);
  this._current = i(0);
  return function(t) {
    return arc(i(t));
  };
}

function updateArc(d) {
  return {depth: d.depth, x: d.x, dx: d.dx};
}

d3.select(self.frameElement).style("height", margin.top + margin.bottom + "px");

</script>

https://d3js.org/d3.v3.min.js