echart 柱图渐变色

<template>
  <div>
    <el-row :gutter="30">
      <el-col :span="12">
        <el-card>
          <div id="typeChart" style=" 600px;height:400px;"></div>
        </el-card>
      </el-col>
      <el-col :span="12">
        <el-card>
          <div id="brandChart" style=" 600px;height:400px;"></div>
        </el-card>
      </el-col>
    </el-row>
  </div>
</template>

<script>
import echarts from "echarts";

export default {
  methods: {
    typeChart() {
      // 基于准备好的dom，初始化echarts实例
      let typeChart = echarts.init(document.getElementById("typeChart"));
      // 指定图表的配置项和数据
      let option = {
        color: ["red"],
        title: {
          text: "类型统计"
        },
        tooltip: {},
        legend: {
          data: ["检测车辆"]
        },
        xAxis: {
          data: ["中原区", "二七区", "金水区", "上街区", "中牟县", "经开区","高新区"]
        },
        yAxis: {},
        series: [
          {
            name: "检测车辆",
            type: "bar",
            barWidth: 20,
            data: [50, 100, 200, 300, 400, 500, 600],
            itemStyle: {
              normal: {
                color: new echarts.graphic.LinearGradient(0, 0, 0, 1, [
                  { offset: 0, color: "#67B6FF" }, //柱图渐变色
                  { offset: 0.5, color: "#44C0C1" }, //柱图渐变色
                  { offset: 1, color: "#06B5D7" } //柱图渐变色
                ])
              }
            }
          }
        ]
      };
      // 使用刚指定的配置项和数据显示图表。
      typeChart.setOption(option);
    },
    brandChart() {
      // 基于准备好的dom，初始化echarts实例
      let brandChart = echarts.init(document.getElementById("brandChart"));
      // 指定图表的配置项和数据
      let option = {
        color: ["red"],
        title: {
          text: "品牌信息"
        },
        tooltip: {},
        legend: {
          data: ["检测车辆"]
        },
        xAxis: {
          data: ["中原区", "二七区", "金水区", "上街区", "中牟县", "经开区","高新区"]
        },
        yAxis: {},
        series: [
          {
            name: "检测车辆",
            type: "bar",
            barWidth: 20,
            data: [50, 140, 200, 300, 400, 500, 400],
            itemStyle: {
              normal: {
                color: new echarts.graphic.LinearGradient(0, 0, 0, 1, [
                  { offset: 0, color: "#67B6FF" }, //柱图渐变色
                  { offset: 0.5, color: "#44C0C1" }, //柱图渐变色
                  { offset: 1, color: "#06B5D7" } //柱图渐变色
                ])
              }
            }
          }
        ]
      };
      // 使用刚指定的配置项和数据显示图表。
      brandChart.setOption(option);
    }
  },
  mounted() {
    this.typeChart();
    this.brandChart();
  }
};
</script>