echarts tooltip属性加背景图片

代码：

        tooltip: {
    
    
          trigger: "item",
          // borderColor: "#12D5FC",
          // backgroundColor: "#033394 80%",
          backgroundColor: "transparent",
          borderWidth: 1,
          padding: 10,
          formatter: function(params) {
    
    
            // var str =params['percent']+'%'+'<br/>'+params.data.value+'笔'
            var str = `<div style = "background:url( ${
      
      require("../../assets/images/mapSelPart.png")}) no-repeat center center ;width:60px;height:60px; ">${
      
      
              params["percent"]
            }%<br/> ${
      
      params.data.value}笔</div>`;
            // parms.marker
            console.log(str);
            return str;
          }
        },