改变legend图标以及样式echarts 饼配置项内容和展示

      option = {
    tooltip: {
        trigger: 'item',
    },
    legend: {
        orient: 'vertical',
        left: 'left',
        icon: 'rect',
        itemWidth: 10,
        itemHeight: 2,
        textStyle: {
         color: 'red'
        },
    },
    series: [
        {
            name: '访问来源',
            type: 'pie',
            radius: '50%',
            data: [
                {value: 1048, name: '搜索引擎'},
                {value: 735, name: '直接访问'},
                {value: 580, name: '邮件营销'},
                {value: 484, name: '联盟广告'},
                {value: 300, name: '视频广告'}
            ],
            emphasis: {
                itemStyle: {
                    shadowBlur: 10,
                    shadowOffsetX: 0,
                    shadowColor: 'rgba(0, 0, 0, 0.5)'
                }
            }
        }
    ]
};