如何用svg修改chart iconecharts 折线配置项内容和展示

      option = {
    legend: {
      //  data:['高度(km)与气温(°C)变化关系']
      data:[{
           name: "Alert State",
          icon: "square",
            //  icon : 'image://../asset/ico/favicon.png',
         // icon: 'path://M1705.06,1318.313v-89.254l-319.9-221.799l0.073-208.063c0.521-84.662-26.629-121.796-63.961-121.491c-37.332-0.305-64.482,36.829-63.961,121.491l0.073,208.063l-319.9,221.799v89.254l330.343-157.288l12.238,241.308l-134.449,92.931l0.531,42.034l175.125-42.917l175.125,42.917l0.531-42.034l-134.449-92.931l12.238-241.308L1705.06,1318.313z'
           //textStyle: {
           //   color: "#222222",
           //   fontSize: "13px",
           //   fontFamily: "Arial"
           //}
       }]
    },
    tooltip: {
        trigger: 'axis',
        formatter: "Temperature : <br/>{b}km : {c}°C"
    },
    grid: {
        left: '3%',
        right: '4%',
        bottom: '3%',
        containLabel: true
    },
    xAxis: {
        type: 'value',
        axisLabel: {
            formatter: '{value} °C'
        }
    },
    yAxis: {
        type: 'category',
        axisLine: {onZero: false},
        axisLabel: {
            formatter: '{value} km'
        },
        boundaryGap: false,
        data: ['0', '10', '20', '30', '40', '50', '60', '70', '80']
    },
    series: [
        {
            name: '高度(km)与气温(°C)变化关系',
            type: 'line',
            smooth: true,
            lineStyle: {
                normal: {
                    width: 3,
                    shadowColor: 'rgba(0,0,0,0.4)',
                    shadowBlur: 10,
                    shadowOffsetY: 10
                }
            },
            data:[15, -50, -56.5, -46.5, -22.1, -2.5, -27.7, -55.7, -76.5]
        },
    	{
			name: "Alert State",
			type: 'line',
			itemStyle: {
	        	normal: {
	        		color: 'rgba(251,222,222,0.5)'
	        	}
	    	}
    	}
    ]
};