let chartBase64 = myChart.getDataURL()
        return chartBase64

drawLine (type) {
      var that = this
      window.addEventListener('resize', this.drawLine)
      let myChart = this.$echarts.init(this.$refs.echarts)
      if (type == 0) {
        var option = {
          tooltip: {
            trigger: 'axis',
            axisPointer: { // 坐标轴指示器，坐标轴触发有效
              type: 'shadow' // 默认为直线，可选为：'line' | 'shadow'
            }
          },
          grid: {
            left: '2%',
            right: '4%',
            bottom: '5%',
            top: '8%',
            containLabel: true
          },
          legend: {
            data: ['预警次数'],
            right: '5%',
            top: 12,
            textStyle: {
              color: '#fff',
              fontSize: 18
            },
            itemWidth: 20,
            itemHeight: 20
          },
          xAxis: {
            type: 'category',
            data: that.xdata,
            axisLine: {
              lineStyle: {
                color: '#274076'
              }
            },
            axisTick: {
              show: false
            },
            axisLabel: {
              textStyle: {
                fontFamily: 'Microsoft YaHei',
                color: 'rgba(143, 178, 204, 1)',
                fontSize: 17

              },
              rotate: 40
            },
          },
          yAxis: {
            type: 'value',
            name: '次数',
            nameTextStyle: {
              fontSize: 17,
              color: 'rgba(143, 178, 204, 1)',
              padding: [0, 0, 0, -50]
            },
            axisLine: {
              show: true,
              lineStyle: {
                color: '#274077'
              }
            },
            axisTick: {
              show: false
            },
            splitLine: {
              show: true,
              lineStyle: {
                color: '#274077',
              }
            },
            axisLabel: {
              textStyle: {
                fontFamily: 'Microsoft YaHei',
                color: 'rgba(143, 178, 204, 1)',
                fontSize: 18
              }
            }
          },
          series: [{
            name: '预警次数',
            type: 'bar',
            barWidth: '30',
            itemStyle: {
              normal: {
                color: new this.$echarts.graphic.LinearGradient(0, 0, 0, 1, [{
                  offset: 0,
                  color: 'rgba(61, 212, 242, 1)'
                }, {
                  offset: 1,
                  color: 'rgba(89, 89, 255, 1)'
                }]),
                barBorderRadius: [20, 20, 0, 0]
              },
            },
            data: that.ydata
          }]
        }
        myChart.clear()
        myChart.resize()
        myChart.setOption(option)
      }
      if (type == 1) {
        let chartBase64 = myChart.getDataURL()
        return chartBase64
      }
    },