adding text in d3.js multi level pie chart

Question

I want to have a multi level pie chart such as here:

The only thing I am not getting to work is how to add text to the pie chart. I want each segment to have a label on it. Now I know how to do this for a single level pie chart but I am not succeeding in this multi level one. If someone could for instance show one example on jsfiddle that would be much appreciated!

http://jsfiddle.net/Qh9X5/304/

CSS

body {
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  margin: auto;
  position: relative;
  width: 960px;
}

text {
  font: 10px sans-serif;
}

form {
  position: absolute;
  right: 10px;
  top: 10px;
}

Javascript

var dataset = {
  apples: [33.3, 33.3, 33.4],
  oranges: [12.5, 12.5, 12.5, 12.5, 12.5, 12.5, 12.5, 12.5],
  lemons: [20, 20, 20, 20, 20],
};

var width = 660,
    height = 500,
    cwidth = 75;

var color = d3.scale.category20();

var pie = d3.layout.pie()
    .sort(null);

var arc = d3.svg.arc();

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height)
    .append("g")
    .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");

var gs = svg.selectAll("g").data(d3.values(dataset)).enter().append("g");
var path = gs.selectAll("path")
    .data(function(d) { return pie(d); })
  .enter().append("path")
    .attr("fill", function(d, i) { return color(i); })
    .attr("d", function(d, i, j) { return arc.innerRadius(10+cwidth*j).outerRadius(cwidth*(j+1))(d); });

Answer 1

d3.svg.arc.centroid is a convenient way to get a point at the center of an arc, which is an OK starting point for labels.

Here's another similar question that shows some additional positioning. Label outside arc (Pie chart) d3.js