echarts饼图，完整圆形，百分比显示

option = {
        tooltip : {
            trigger: 'item',
            formatter: "{a} <br/>{b} : {c} ({d}%)"
        },
        color:['#8fc31f','#f35833','#00ccff','#ffcc00'],
        legend: {
            orient: 'vertical',
            x: 'right',
            data: ['准时','迟到','请假','未到'],
            formatter:function(name){
                var oa = option.series[0].data;
                var num = oa[0].value + oa[1].value + oa[2].value + oa[3].value;
                for(var i = 0; i < option.series[0].data.length; i++){
                    if(name==oa[i].name){
                        return name + '     ' + oa[i].value + '     ' + (oa[i].value/num * 100).toFixed(2) + '%';
                    }
                }
            }
        },
        series : [
            {
                name: '签到比例分析',
                type: 'pie',
                radius : '55%',
                center: ['40%', '50%'],
                data:[
                    {value:335, name:'准时'},
                    {value:310, name:'迟到'},
                    {value:234, name:'请假'},
                    {value:135, name:'未到'}
                ],
                itemStyle: {
                    emphasis: {
                        shadowBlur: 10,
                        shadowOffsetX: 0,
                        shadowColor: 'rgba(0, 0, 0, 0.5)'
                    }
                },
                itemStyle: {
                    normal: {
                        label:{ 
                            show: true, 
//                                position:'inside',
                            formatter: '{b} : {c} ({d}%)' 
                        }
                    },
                    labelLine :{show:true}
                }
            }
        ]
    };