仪表echarts 20%配置项内容和展示

      var dataArr = 15;
                var colorSet = {
                    color: '#468EFD'
                };
                var option = {
                    backgroundColor:'#000',
                    tooltip: {
                        formatter: "{a} <br/>值 : {c}"
                    },
                    grid: {
                        top: 0,
                        left: 0,
                        right: 0,
                        bottom: 0,
                    },
                    series: [{
                        name: "内部进度条",
                        type: "gauge",
                        //center: ['20%', '50%'],
                        radius: '48%',
                        min: 0, //最小刻度
                        max: 20, //最大刻度
                        startAngle: 180,
                        endAngle: 0,
                        axisLine: {
                            lineStyle: {
                                color: [
                                    [dataArr / 20, colorSet.color],
                                    [1, "#111F42"]
                                ],
                                width: 3
                            }
                        },
                        axisLabel: {
                            show: false,
                        },
                        axisTick: {
                            show: false,

                        },
                        splitLine: {
                            show: false,
                        },
                        itemStyle: {
                            show: false,
                        },
                        detail: {

                            offsetCenter: [0, -50],
                            textStyle: {
                                fontSize: 20,
                                fontWeight: '700',
                                color: colorSet.color
                            },
                        },
                        title: { //标题
                            show: true,
                            offsetCenter: [0, -5], // x, y，单位px
                            textStyle: {
                                color: "#ff0",
                                fontSize: 30, //表盘上的标题文字大小
                                fontWeight: 400,
                                fontFamily: 'PingFangSC'
                            }
                        },
                        data: [{
                            name: "m/min",
                            value: dataArr,
                        }],
                        pointer: {
                            show: true,
                            length: '75%',
                            radius: '20%',
                            width: 5, //指针粗细
                        },
                        animationDuration: 4000,
                    }, {
                        name: '外部刻度',
                        type: 'gauge',
                        //  center: ['20%', '50%'],
                        radius: '50%',
                        min: 0, //最小刻度
                        max: 20, //最大刻度
                        splitNumber: 6, //刻度数量
                        startAngle: 180,
                        endAngle: 0,
                        axisLine: {
                            show: true,
                            lineStyle: {
                                width: 1,
                                color: [
                                    [1, 'rgba(0,0,0,0)']
                                ]
                            }
                        }, //仪表盘轴线
                        axisLabel: {
                            show: true,
                            color: '#ff0',
                            distance: 35,
                            fontSize: 20,
                            formatter: function(v) {
                                switch (v + '') {
                                    case '0':
                                        return '0';
                                    case '10':
                                        return '10';
                                    case '20':
                                        return '20';
                                }
                            }
                        }, //刻度标签。
                        axisTick: {
                            show: true,
                            splitNumber: 5,
                            lineStyle: {
                                color: '#ff0', //用颜色渐变函数不起作用
                                width: 1,
                            },
                            length: -8
                        }, //刻度样式
                        splitLine: {
                            show: true,
                            length: -20,
                            lineStyle: {
                                color: '#ff0', //用颜色渐变函数不起作用
                            }
                        }, //分隔线样式
                        detail: {
                            show: false
                        },
                        pointer: {
                            show: true
                        }
                    }]
                }