canvas下面积消失

描述:当前是关于Echarts图表中的 雷达图 示例。
 
            option = {
      tooltip: {
        trigger: 'axis'
      },
      calculable: true,
      radar: {
        name: {
          textStyle: {
            color: '#000',
            fontSize: 18,
            fontWeight: 600,
          }
        },
        splitArea: {
          areaStyle: {
            color: '#fff',
            shadowColor: 'rgba(0, 0, 0, 1)',
            shadowBlur: 20,
            opacity: 1
          }
        },
        splitLine: {
          lineStyle: {

          }
        },
        indicator: [
          { text: '销售天才', max: 100 },
          { text: '伯乐慧眼', max: 100 },
          { text: '单品大咖', max: 100 },
          { text: '晋升达人', max: 100 },
          { text: '积极分子', max: 100 },
        ],
        splitNumber: 8,
        radius: 80,
      }
      ,
      series: [
        {
          name: '完全实况球员数据',
          type: 'radar',
          symbolSize: 1,
          itemStyle: {
            normal: {
              areaStyle: {
                color: '#FED502',
                type: 'default'
              },
              lineStyle: {
                color: '#FED502'
              }
            }
          },
          data: [
            {
              value: [60, 30, 30, 30, 60],
              name: '个人数据'
            }
          ]
        }
      ]
    }