label不能垂直居中echarts scatter配置项内容和展示

windows电脑 scatter 的label不能垂直居中

      var geoCoordMap = {
    "海门":[121.15,31.89],
    "鄂尔多斯":[109.781327,39.608266],
    "招远":[120.38,37.35],
};

var convertData = function (data) {
    var res = [];
    for (var i = 0; i < data.length; i++) {
        var geoCoord = geoCoordMap[data[i].name];
        if (geoCoord) {
            res.push({
                name: data[i].name,
                value: geoCoord.concat(data[i].value)
            });
        }
    }
    return res;
};

option = {
    backgroundColor: '#404a59',
    visualMap: {
        min: 0,
        max: 200,
        calculable: true,
        inRange: {
            color: ['#50a3ba', '#eac736', '#d94e5d']
        },
        textStyle: {
            color: '#fff'
        }
    },
    geo: {
        map: 'china',
        label: {
            emphasis: {
                show: false
            }
        },
        itemStyle: {
            normal: {
                areaColor: '#323c48',
                borderColor: '#111'
            },
            emphasis: {
                areaColor: '#2a333d'
            }
        }
    },
    series: [
        {
            name: 'pm2.5',
            type: 'scatter',
            coordinateSystem: 'geo',
            data: convertData([
                {name: "海门", value: 9},
                {name: "鄂尔多斯", value: 12},
                {name: "招远", value: 12},
            ]),
            symbolSize: 20,
            label: {
                normal: {
                    show: true,
                    formatter: function(value){
                           return 1
                    }
                },
                emphasis: {
                    show: false
                }
            },
            itemStyle: {
                emphasis: {
                    borderColor: '#fff',
                    borderWidth: 1
                }
            }
        }
    ]
}