Echarts是如何实现饼图自动提示的

Question

如下图：

是写js实现的吗？还是echarts本身的特性？

Answer 1

https://www.echartsjs.com/zh/...

这个应该可以，使用dispatchAction触发，我写的Demo

option = {
    title: {
        text: '某站点用户访问来源',
        subtext: '纯属虚构',
        left: 'center'
    },
    tooltip: {
        trigger: 'item',
        formatter: '{b} : {c} ({d}%)'
    },
    legend: {
        orient: 'vertical',
        left: 'left',
        data: ['直接访问', '邮件营销', '联盟广告', '视频广告', '搜索引擎']
    },
    series: [
        {
            name: '访问来源',
            type: 'pie',
            radius: '55%',
            center: ['50%', '60%'],
            data: [
                {value: 335, name: '直接访问'},
                {value: 310, name: '邮件营销'},
                {value: 234, name: '联盟广告'},
                {value: 135, name: '视频广告'},
                {value: 1548, name: '搜索引擎'}
            ],
            emphasis: {
                itemStyle: {
                    shadowBlur: 10,
                    shadowOffsetX: 0,
                    shadowColor: 'rgba(0, 0, 0, 0.5)'
                }
            }
        }
    ]
};

let lastIndex = 0;
let currentIndex = 0;
setInterval(() => {
    myChart.dispatchAction({
        type: 'downplay',
        seriesIndex: 0,
        dataIndex: lastIndex,
    });
    myChart.dispatchAction({
        type: 'highlight',
        seriesIndex: 0,
        dataIndex: currentIndex,
    });
    myChart.dispatchAction({
        type: 'showTip',
        seriesIndex: 0,
        dataIndex: currentIndex,
    });
    lastIndex = currentIndex;
    ++currentIndex;
    if(currentIndex > 4) {
        currentIndex = 0;
    }
}, 1000)

Answer 2

echarts有相关的事件，在事件接口里面找dispatchAction
highlight 这两个关键字