javascript - D3 圆环图图例或悬停标签

Question

我在这里使用 D3.js 创建了一个图表 ( http://jsfiddle.net/jkuchta/u57mt97c/ )，但我遇到了标签问题。我如何添加图例或让标签仅出现在悬停时？

// DRAW SLICE LABELS
var sliceLabel = label_group.selectAll("text")
    .data(donut(data.pct));
sliceLabel.enter().append("svg:text")
    .attr("class", "arcLabel")
    .attr("transform", function(d) {return "translate(" + arc.centroid(d) + ")"; })
    .attr("text-anchor", "middle")
    .text(function(d, i) {return labels[i]; });

Answer 1

我最终使用下面的内容创建了图表。 fiddle (https://jsfiddle.net/dp50bLmo/)

<style>
    .legend { margin: 0 0 20px 20px; }
    .chartLabel { font: 14px sans-serif; fill: #000; }
    .arcLabel { font: 11px sans-serif; fill: #fff; }
    .bar { min-height: 100%; height: 156px !important; }
</style>

<script type="text/javascript">
    function build_chart(data, labels, chart_selector) {
      var total = 0;
      for(i = 0; i < data.pct.length; i++) {
        total += data.pct[i];
      }
      var w = 320,
        h = 320,
        r = Math.min(w, h) / 2,
        dur = 750,
        color = d3.scale.category10(),
        donut = d3.layout.pie().sort(null),
      arc = d3.svg.arc().innerRadius(r - 70).outerRadius(r - 20);
      var svg = d3.select(chart_selector).append("svg:svg")
        .attr("width", w).attr("height", h);
      var arc_grp = svg.append("svg:g")
        .attr("class", "arcGrp")
        .attr("transform", "translate(" + (w / 2) + "," + (h / 2) + ")");
      var label_group = svg.append("svg:g")
        .attr("class", "lblGroup")
        .attr("transform", "translate(" + (w / 2) + "," + (h / 2) + ")");
      var center_group = svg.append("svg:g")
        .attr("class", "ctrGroup")
        .attr("transform", "translate(" + (w / 2) + "," + (h / 2) + ")");
      var pieLabel = center_group.append("svg:text")
        .attr("dy", ".35em").attr("class", "chartLabel")
        .attr("text-anchor", "middle")
        .text(data.label);
      var arcs = arc_grp.selectAll("path")
        .data(donut(data.pct));
      arcs.enter().append("svg:path")
        .attr("stroke", "white")
        .attr("stroke-width", 0.5)
        .attr("fill", function(d, i) {return color(i);})
        .attr("d", arc)
        .each(function(d) {this._current = d});
      var sliceLabel = label_group.selectAll("text")
        .data(donut(data.pct));
      sliceLabel.enter().append("svg:text")
        .attr("class", "arcLabel")
        .attr("transform", function(d) {return "translate(" + arc.centroid(d) + ")"; })
        .attr("text-anchor", "middle")
        .text(function(d, i) {return (data.pct[i] / total * 100).toFixed(1) + "%"; });
      var legend = d3.select(chart_selector).append("svg")
        .attr("class", "legend")
        .attr("width", w)
        .attr("height", 22 * labels.length)
        .selectAll("g")
        .data(color.domain().slice())
        .enter().append("g")
        .attr("transform", function(d, i) { return "translate(0," + i * 20 + ")"; });
      legend.append("rect")
        .attr("width", 18)
        .attr("height", 18)
        .style("fill", color);
      legend.append("text")
        .attr("x", 24)
        .attr("y", 9)
        .attr("dy", ".35em")
        .text(function(d, i) { return labels[i]; });
    }
</script>

<script type="text/javascript">
    $(function(){
        var chart_selector = '#chart';
        var data = { label: 'Test Chart', pct: [] };
        var labels = ['Label 1', 'Label 2', 'Label 3', 'Label 4'];
        data.pct = [.1, .3, .4, .2];

        build_chart(data, labels, chart_selector);
    });
</script>
<div id="chart"></div>