饼图legend显示百分比

有时候咱们须要在饼图的legend上显示百分比 

var option6 = {
          color: ['#00a65a', '#00c0ef', '#f39c12', '#f56954', '#0d84df', '#ca04d6', '#e2ce27', '#a3d252', '#13cabf', '#42c78a'],
          title: {
              text: '今年各行业用气占比',
              x: '270',
              y: 'top',
              textStyle: {
                  fontSize: 16,
              }
          },
          tooltip: {
              trigger: 'item',
              formatter: "{a} <br/>{b}: {c} ({d}%)"
          },

          legend: {
              orient: 'vertical',
              x: '0',
              top: '80',
              itemGap: 15,
              formatter: function(name) {
                  var data = option6.series[0].data;
                  var total = 0;
                  var tarValue;
                  for (var i = 0, l = data.length; i < l; i++) {
                      total += data[i].value;
                      if (data[i].name == name) {
                          tarValue = data[i].value;
                      }
                  }
                  var p = (tarValue / total * 100).toFixed(2);
                  return name + ' ' + ' ' + '(' + p + '%)';
              },
              data: ['行业1', '行业2', '行业3', '行业4', '行业5', '行业6', '行业7', '行业8', '行业9', '行业10'],

          },
          series: [{
              name: '今年各行业用气占比',
              type: 'pie',
              center: ['70%', '50%'],
              radius: ['30%', '65%'],
              label: {

              },
              labelLine: {

              },

              data: [
                  { value: 335, name: '行业1', },
                  { value: 310, name: '行业2', },
                  { value: 234, name: '行业3', },
                  { value: 335, name: '行业4', },
                  { value: 310, name: '行业5', },
                  { value: 234, name: '行业6', },
                  { value: 234, name: '行业7', },
                  { value: 335, name: '行业8', },
                  { value: 310, name: '行业9', },
                  { value: 234, name: '行业10', },
              ]
          }]
      };
      var myarea1 = echarts.init(document.getElementById('chart-area1'), pietheme);
      myarea1.setOption(option6);