Pie Chart Example

Example from the talk given by Kent English:

<!DOCTYPE html>
<head>
    <meta charset="utf-8">
    <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
    <link rel="stylesheet" type="text/css" href="styles.css">
</head>

<body>
    <div id="chart"></div>
  	<p>Click on the legend to filter</p>
    <script>
        var tooltip = d3.select('#chart')
            .append('div')
            .attr('class', 'tooltip');

tooltip.append('div')
            .attr('class', 'label');

tooltip.append('div')
            .attr('class', 'count');

tooltip.append('div')
            .attr('class', 'percent');

d3.csv('weekdays.csv', function(error, dataset) {
            dataset.forEach(function(d) {
                d.count = +d.count;
                d.enabled = true;
            });

var pie = d3.layout.pie()
                .value(function(d) {
                    return d.count;
                })
                .sort(null);

var path = svg.selectAll('path')
                .data(pie(dataset))
                .enter()
                .append('path')
                .attr('d', arc)
                .attr('fill', function(d, i) {
                    return color(d.data.label);
                })
                .each(function(d) {
                    this._current = d;
                });

var legendRectSize = 18;

var legendSpacing = 4;

var legend = svg.selectAll('.legend')
                .data(color.domain())
                .enter()
                .append('g')
                .attr('class', 'legend')
                .attr('transform', function(d, i) {
                    var height = legendRectSize + legendSpacing;
                    var offset = height * color.domain().length / 2;
                    var horz = -2 * legendRectSize;
                    var vert = i * height - offset;
                    return 'translate(' + horz + ',' + vert + ')';
                });

legend.append('rect')
                .attr('width', legendRectSize)
                .attr('height', legendRectSize)
                .style('fill', color)
                .style('stroke', color)
                .on('click', function(label) {
                    var rect = d3.select(this);
                    var enabled = true;
                    var totalEnabled = d3.sum(dataset.map(function(d) {
                        return (d.enabled) ? 1 : 0;
                    }));

if (rect.attr('class') === 'disabled') {
                        rect.attr('class', '');
                    } else {
                        if (totalEnabled < 2) return;
                        rect.attr('class', 'disabled');
                        enabled = false;
                    }

pie.value(function(d) {
                        if (d.label === label) d.enabled = enabled;
                        return (d.enabled) ? d.count : 0;
                    });

path = path.data(pie(dataset));

path.transition()
                        .duration(750)
                        .attrTween('d', function(d) {
                            var interpolate = d3.interpolate(this._current, d);
                            this._current = interpolate(0);
                            return function(t) {
                                return arc(interpolate(t));
                            };
                        });
                });

legend.append('text')
                .attr('x', legendRectSize + legendSpacing)
                .attr('y', legendRectSize - legendSpacing)
                .text(function(d) {
                    return d;
                });

path.on('mouseover', function(d) {
                var total = d3.sum(dataset.map(function(d) {
                    return (d.enabled) ? d.count : 0;
                }));

var percent = Math.round(1000 * d.data.count / total) / 10;
                tooltip.select('.label').html(d.data.label);
                tooltip.select('.count').html(d.data.count);
                tooltip.select('.percent').html(percent + '%');
                tooltip.style('display', 'block');
            });
            path.on('mouseout', function() {
                tooltip.style('display', 'none');
            });

path.on('mousemove', function(d) {
                tooltip.style('top', (d3.event.pageY + 10) + 'px')
                    .style('left', (d3.event.pageX + 10) + 'px');
            });

});

var width = 360;
        var height = 360;
        var radius = Math.min(width, height) / 2;
        var color = d3.scale.category20b();

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

var donutWidth = 75;

var arc = d3.svg.arc()
            .innerRadius(radius - donutWidth) // NEW
            .outerRadius(radius);
    </script>
</body>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js