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I. Introduction
This article comes from the actual large-screen demand. Since I took a detour for a long time, I deliberately recorded it. The main purpose is to realize the default selection and timing switching selection effects of the stacked histogram in echarts ;
2. Rendering
The general effect diagram is as follows:
3. Realization of effect
The core of switching lies in dispatchActionthe (the official website address is as follows: https://echarts.apache.org/zh/api.html#action.highlight ), this method has two parameters in the type item, which are highlightand showTip, these two parameters are used here. The description of these two parameters is as follows:
3.1 highlight
The main function of highlight is to highlight the graph , in other words, this setting in the histogram can make the histogram in a highlighted state
// 如果要高亮系列：
dispatchAction({
type: 'highlight',
// 用 index 或 id 或 name 来指定系列。
// 可以使用数组指定多个系列。
seriesIndex?: number | number[],
seriesId?: string | string[],
seriesName?: string | string[],
// 数据项的 index，如果不指定也可以通过 name 属性根据名称指定数据项
dataIndex?: number | number[],
// 可选，数据项名称，在有 dataIndex 的时候忽略
name?: string | string[],
});
Specific highlight effect, effect:
the white background bar here is the highlight effect;
3.2 showTip
The function of this parameter is to actively display tips, which is the small white box in the legend above
dispatchAction({
type: 'showTip',
// 系列的 index，在 tooltip 的 trigger 为 axis 的时候可选。
seriesIndex?: number,
// 数据项的 index，如果不指定也可以通过 name 属性根据名称指定数据项
dataIndex?: number,
// 可选，数据项名称，在有 dataIndex 的时候忽略
name?: string,,
// 本次显示 tooltip 的位置。只在本次 action 中生效。
// 缺省则使用 option 中定义的 tooltip 位置。
position: number[] | string | Function,
})
After executing this code, you can specify the tips display of the image;
3.3 Implementation code
Knowing the API for highlighting and displaying tips, then it will be convenient
// 取消之前高亮的图形
chart.dispatchAction({
type: "downplay",
seriesIndex: option.yAxis.data.length,
dataIndex: app.currentIndex,
});
// 计算下一个高亮的位置
app.currentIndex =
app.currentIndex - 1 > -1
? app.currentIndex - 1
: option.yAxis.data.length;
// 执行高亮
chart.dispatchAction({
type: "highlight",
seriesIndex: 0,
dataIndex: app.currentIndex,
});
// 执行
chart.dispatchAction({
type: "showTip",
seriesIndex: 0,
dataIndex: app.currentIndex,
});
It should be noted here that before performing highlighting, it is necessary to cancel the previous highlighting for the sake of safety , so as to ensure that the results are in line with expectations when performing highlighting;
3.4 Overall code
The following is the complete code, the specific effect is the effect of the second chapter of this article;
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
html,
body {
position: relative;
width: 100%;
height: 100%;
margin: 0;
padding: 0;
}
.main {
position: relative;
width: 100%;
height: 100%;
padding: 20px;
box-sizing: border-box;
background-color: #333333;
}
</style>
</head>
<body>
<div class="main" id="app"></div>
<script src="https://cdn.bootcdn.net/ajax/libs/echarts/5.4.2/echarts.js"></script>
<script>
let chart = echarts.init(document.getElementById("app"));
let option = {
tooltip: {
trigger: "axis",
axisPointer: {
// Use axis to trigger tooltip
type: "shadow", // 'shadow' as default; can also be 'line' or 'shadow'
},
},
legend: {
},
grid: {
left: "3%",
right: "4%",
bottom: "3%",
containLabel: true,
},
xAxis: {
type: "value",
},
yAxis: {
type: "category",
data: ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"],
},
series: [
{
name: "Direct",
type: "bar",
stack: "total",
label: {
show: true,
},
emphasis: {
focus: "series",
},
data: [320, 302, 301, 334, 390, 330, 320],
},
{
name: "Mail Ad",
type: "bar",
stack: "total",
label: {
show: true,
},
emphasis: {
focus: "series",
},
data: [120, 132, 101, 134, 90, 230, 210],
},
{
name: "Affiliate Ad",
type: "bar",
stack: "total",
label: {
show: true,
},
emphasis: {
focus: "series",
},
data: [220, 182, 191, 234, 290, 330, 310],
},
],
};
chart.setOption(option);
var app = {
currentIndex: option.yAxis.data.length,
};
setInterval(() => {
// 取消之前高亮的图形
chart.dispatchAction({
type: "downplay",
seriesIndex: option.yAxis.data.length,
dataIndex: app.currentIndex,
});
app.currentIndex =
app.currentIndex - 1 > -1
? app.currentIndex - 1
: option.yAxis.data.length;
chart.dispatchAction({
type: "highlight",
seriesIndex: 0,
dataIndex: app.currentIndex,
});
chart.dispatchAction({
type: "showTip",
seriesIndex: 0,
dataIndex: app.currentIndex,
});
}, 1000);
</script>
</body>
</html>
Four. Summary
The function of echarts is very powerful. The default selection and timing switching in this article mainly borrow the highlight and showTip in the dispatchAction API ; specify the graphic highlight through highlight , then display the prompt window through **showTip , and finally execute the timing through setInterval Switching completes this requirement (of course, setInterval has certain problems, which can be solved by recursive setTimeout);