柱状堆叠图 数字位置显示不对

[shen-lan]

        series: [
          {
            name: '完成工时',
            data: [],
            type: 'bar',
            stack: 'a',
            label: {
              show: true,
              position: 'center',
              offset: [0, 0],
              style: {
                fontSize: 20,
                fill: '#fff'
              }
            }            
          },
          {
            name: '剩余工时',
            data: [],
            type: 'bar',
            stack: 'a',
            label: {
              show: true,
              position: 'center',
              offset: [0, 0],
              style: {
                fontSize: 20,
                fill: '#fff'
              }
            }            
          }                                                      
        ]

[shen-lan]

position: 'center',显示不准啊