桑基图文字自上而下显示的图列

桑基图文字要自上而下显示

option = {
  series: {
    type: 'sankey',
    layout: 'none',
    top: '30%',
     data: [
        { name: '班级A' },
        { name: '班级B' },
        { name: '班级C' },
        { name: '班级D' }
      ],
      links: [
        { source: '班级A', target: '班级B', value: 10 },
        { source: '班级B', target: '班级C', value: 15 },
        { source: '班级C', target: '班级D', value: 20 }
      ],
    orient: 'vertical',
    levels: [{
      label: {
         position: 'top',
         distance: 10,
        // rotate:-90,
        formatter: (params) => {
          return params.name.split('').join('\n');
        },
      },
      depth: 0
    },{
      label: {
         position: 'top',
        distance: 13.5
        
      },
      depth: 1
    },{
      label: {
         position: 'bottom',
        distance: 13.5
      },
      depth: 2
    },{
      label: {
        show: true,
         position: 'bottom',
        distance: 13.5
      },
      depth: 3
    }]
  }
};