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Pie Chart Update, V
license: gpl-3.0

This example demonstrates using a data-join with a key function to update a pie chart.

Previous: Static Data-Join

region fruit count
East Apples 53245
West Apples 28479
South Apples 19697
North Apples 24037
Central Apples 40245
East Oranges 200
South Oranges 200
Central Oranges 200
<!DOCTYPE html>
<meta charset="utf-8">
<style>
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;
}
input {
margin: 0 7px;
}
</style>
<form></form>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>
var width = 960,
height = 500,
radius = Math.min(width, height) / 2;
var color = d3.scale.category20();
var pie = d3.layout.pie()
.value(function(d) { return d.count; })
.sort(null);
var arc = d3.svg.arc()
.innerRadius(radius - 100)
.outerRadius(radius - 20);
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height)
.append("g")
.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");
var path = svg.selectAll("path");
d3.tsv("data.tsv", type, function(error, data) {
var regionsByFruit = d3.nest()
.key(function(d) { return d.fruit; })
.entries(data)
.reverse();
var label = d3.select("form").selectAll("label")
.data(regionsByFruit)
.enter().append("label");
label.append("input")
.attr("type", "radio")
.attr("name", "fruit")
.attr("value", function(d) { return d.key; })
.on("change", change)
.filter(function(d, i) { return !i; })
.each(change)
.property("checked", true);
label.append("span")
.text(function(d) { return d.key; });
function change(region) {
var data0 = path.data(),
data1 = pie(region.values);
path = path.data(data1, key);
path.enter().append("path")
.each(function(d, i) { this._current = findNeighborArc(i, data0, data1, key) || d; })
.attr("fill", function(d) { return color(d.data.region); })
.append("title")
.text(function(d) { return d.data.region; });
path.exit()
.datum(function(d, i) { return findNeighborArc(i, data1, data0, key) || d; })
.transition()
.duration(750)
.attrTween("d", arcTween)
.remove();
path.transition()
.duration(750)
.attrTween("d", arcTween);
}
});
function key(d) {
return d.data.region;
}
function type(d) {
d.count = +d.count;
return d;
}
function findNeighborArc(i, data0, data1, key) {
var d;
return (d = findPreceding(i, data0, data1, key)) ? {startAngle: d.endAngle, endAngle: d.endAngle}
: (d = findFollowing(i, data0, data1, key)) ? {startAngle: d.startAngle, endAngle: d.startAngle}
: null;
}
// Find the element in data0 that joins the highest preceding element in data1.
function findPreceding(i, data0, data1, key) {
var m = data0.length;
while (--i >= 0) {
var k = key(data1[i]);
for (var j = 0; j < m; ++j) {
if (key(data0[j]) === k) return data0[j];
}
}
}
// Find the element in data0 that joins the lowest following element in data1.
function findFollowing(i, data0, data1, key) {
var n = data1.length, m = data0.length;
while (++i < n) {
var k = key(data1[i]);
for (var j = 0; j < m; ++j) {
if (key(data0[j]) === k) return data0[j];
}
}
}
function arcTween(d) {
var i = d3.interpolate(this._current, d);
this._current = i(0);
return function(t) { return arc(i(t)); };
}
</script>
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