How to make rich text in Echarts change as dataZoom slides?

ECharts rich text dynamic update links with DataZoom

In the ECharts chart, synchronous update of rich text content with DataZoom components is required to cleverly combine DataZoom event listening and dynamic configuration updates. This article will explain in detail how to solve the problem of rich text not being updated when sliding DataZoom.

Many users want rich text in the chart (such as X-axis labels containing icons and text) to dynamically adjust the display content as the DataZoom component slides. However, by default, rich text does not automatically respond to DataZoom's range changes.

According to known configuration, you have set the rich text format in axisLabel.formatter on the X-axis. But when DataZoom slides, rich text (especially icons) fails to sync updates.

The key to solving this problem is:

1. Make sure DataZoom is configured correctly: Make sure dataZoom components are correctly associated with the corresponding X-axis. xAxisIndex property should correctly specify the target X-axis index.
2. Listen to DataZoom events: By listening to dataZoom events, an update operation is triggered when the DataZoom range changes.
3. Dynamically update rich text: In the event callback function, axisLabel.formatter or the entire xAxis configuration of the X-axis is recalculated and updated according to the current range of DataZoom, thereby realizing dynamic display of rich text.

The following provides an improvement:

 let option = {
    // ...Other configurations...
    dataZoom: [{
        type: 'slider',
        show: true,
        xAxisIndex: [0, 1], // Make sure the index is correct start: 0,
        end: 30,
        height: 20
    }],
    // ...Other configurations...
    xAxis: [
        {
            // ...
            axisLabel: {
                formatter: function(value) {
                    // Dynamically generate rich text based on DataZoom range return generateRichText(value); //Custom function}
            }
        },
        {
            // ...
            axisLabel: {
                formatter: function(value) {
                    // Dynamically generate rich text based on DataZoom range return generateRichText(value); //Custom function}
            }
        }
    ]
};


//Custom function, generate rich text function according to DataZoom scope generateRichText(value) {
    // Get the current DataZoom range (need to be obtained from myChart.getOption().dataZoom[0])
    const dataZoomRange = myChart.getOption().dataZoom[0];
    const startIndex = dataZoomRange.startValue;
    const endIndex = dataZoomRange.endValue;

    // Decide which rich text elements are displayed based on the value and scope // ... (The specific logic needs to be written according to your data structure here) ...
    // For example, if the value is in scope, a rich text string containing the icon and text is returned; otherwise, an empty string or simple text is returned.

    // Example: Suppose you have data array data and icon array icons
    const index = value - startIndex;
    if (index >= 0 && index <p> This scheme dynamically generates rich text content based on the scope of DataZoom through <code>generateRichText</code> function, and resets <code>xAxis</code> <code>axisLabel.formatter</code> in the <code>datazoom</code> event listener. Please adjust the logic of the <code>generateRichText</code> function according to your actual data structure and rich text format. Make sure to get <code>myChart.getOption().dataZoom[0]</code> correctly in <code>generateRichText</code> to get the latest DataZoom range. Remember to replace <code>data</code> and <code>icons</code> in the example for your actual data.</p><p> With this approach, your ECharts rich text will be able to change dynamically as DataZoom slides. If you still encounter problems, check if the data source, icon path, and ECharts version are compatible with this dynamic update method.</p>

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