Circle Packing

Enclosure diagrams use containment to represent the hierarchy. Although circle packing is not as space-efficient as a treemap, it better reveals the hierarchy. Implementation based on work by Jeff Heer. Data shows the Flare class hierarchy, also courtesy Jeff Heer.

See also this zoomable version.

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

circle {
  fill: rgb(31, 119, 180);
  fill-opacity: .25;
  stroke: rgb(31, 119, 180);
  stroke-width: 1px;
}

.leaf circle {
  fill: #ff7f0e;
  fill-opacity: 1;
}

text {
  font: 10px sans-serif;
  text-anchor: middle;
}

</style>
<svg width="960" height="960"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var svg = d3.select("svg"),
    diameter = +svg.attr("width"),
    g = svg.append("g").attr("transform", "translate(2,2)"),
    format = d3.format(",d");

var pack = d3.pack()
    .size([diameter - 4, diameter - 4]);

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

root = d3.hierarchy(root)
      .sum(function(d) { return d.size; })
      .sort(function(a, b) { return b.value - a.value; });

var node = g.selectAll(".node")
    .data(pack(root).descendants())
    .enter().append("g")
      .attr("class", function(d) { return d.children ? "node" : "leaf node"; })
      .attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });

node.append("title")
      .text(function(d) { return d.data.name + "\n" + format(d.value); });

node.append("circle")
      .attr("r", function(d) { return d.r; });

node.filter(function(d) { return !d.children; }).append("text")
      .attr("dy", "0.3em")
      .text(function(d) { return d.data.name.substring(0, d.r / 3); });
});

</script>

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