.net 在echarts折线图 怎么在图表中某个位置加入文字 像图中效果这样，求指教 谢谢

类似这样，在toolTip里面写就可以了

  //初始化EChatrs
    var tempChart = echarts.init(document.getElementById('temp'));

    //定义ECharts的Value
    var tempXData = [];
    var supplyTempYData = [];
    var returnTempYData = [];

    //显示温度曲线
    function setTempData(data) {

        tempXData.splice(0, tempXData.length);
        supplyTempYData.splice(0, supplyTempYData.length);
        returnTempYData.splice(0, returnTempYData.length);

        for (var i = 0; i < data.length; i++) {
            tempXData.push(data[i].SavedDatetime.substr(0, 10));
            supplyTempYData.push(data[i].SupplyWaterTemp);
            returnTempYData.push(data[i].ReturnWaterTemp);
        }

        tempChart.setOption(TempDataoption);
    }

    var TempDataoption = {
            tooltip: {
                trigger: 'axis',
                formatter:function(params) {
                    var result = params[0].name + '<br />';
                    params.forEach(function (item) {
                        result += '<span style="display:inline-block;margin-right:5px;border-radius:10px;width:9px;height:9px;background-color:' + item.color + '"></span> ' + item.seriesName + ' : ' + item.data + '℃<br />';
                    });

                    return result;
                }
            },
            legend: {
                data: ['供水温度', '回水温度']
            },
            toolbox: {
                show: true,
                feature: {
                    dataZoom: {
                        yAxisIndex: 'none'
                    },
                    dataView: { readOnly: true },
                    magicType: { type: ['line', 'bar'] },
                    restore: {},
                    saveAsImage: {}
                }
            },
            xAxis: {
                type: 'category',
                boundaryGap: false,
                data: tempXData
            },
            yAxis: {
                type: 'value',
                boundaryGap: false,
                axisLabel: {
                    formatter: '{value} °C'
                }
            },
            dataZoom: [
                {
                    type: 'slider',
                    show: true,
                    xAxisIndex: [0]
                },
                {
                    type: 'inside',
                    xAxisIndex: [0]
                }
            ],
            series: [
                {
                    name: '供水温度',
                    type: 'line',
                    data: supplyTempYData
                },
                {
                    name: '回水温度',
                    type: 'line',
                    data: returnTempYData
                },

            ]
    };

toolTip里面写