Echarts histograma texto exibido verticalmente na coluna

var option={
	series:[{
          name: '', 
          type: 'bar', //类型                  
          data: [820],
          label: {
              show: true,
              position: 'insideBottom',
              color: '#FFFFFF',
              formatter: function (params) {
                     let txtArry = params.seriesName.split('');
                     let rs = "";
                     for (var i = 0; i < txtArry.length; i++) {
                           rs += txtArry[i] + "\n";
                      }
                      return rs;
                 }
            },
             itemStyle: {//柱状图样式
                 normal: {
                      color: '#13AF82'
                 }
              }
         }]
}