echarts柱状图背景重叠组合而非并列的实现代码

// base64位背景图 此处可以改为相对路径 var barImage = './img/chart_bg.png';
// 在线上转base64位工具 https://www.sojson.com/image2base64.html 
var barImage = 'data:image/png;base64,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'; 
var PatternImgA = new Image();
PatternImgA.src = barImage;

 series: [
 {
     type: 'bar',
     data: arr,
     barWidth: 16,
     barCategoryGap: 23,
     margin: [0, 0, 0, 16],
     itemStyle: {
     	 //渐变色，也可以直接用数组给不同的柱子设置不同的颜色
       color: function (params) {
         return colorList[params.dataIndex];
       },
       barBorderRadius: [16, 16, 0, 0],
     },
     label: {
       show: true,
       fontSize: 12,
       position: 'top',
       color: '#AAAAAA',
     }
   },
   {
   	 //这里设置包含关系，只需要这一句话
     barGap: "-100%", 
     type: 'bar',
     data: arr,
     barWidth: 16,
     barCategoryGap: 23,
     itemStyle: {
     	 //此处引入条纹背景
       color: { image: PatternImgA, repeat: 'repeat' }, 
       barBorderRadius: [16, 16, 0, 0],
       xAxisIndex: 2,
       yAxisIndex: 2,
       zlevel: 2
     }
   }
 ]