Modifying ECharts Cursor: Making it Move on Background (2024)

Abstract: Learn how to make the cursor move on the background of an ECharts chart, not just the series.

2024-08-07 by DevCodeF1 Editors

Modifying ECharts Cursor: Making Move Background on User Hover

ECharts is a powerful, interactive charting and visualization library for the browser. By default, ECharts provides a simple cursor that changes shape depending on the user's interaction with the chart. However, sometimes you may want to customize this cursor and make it more obvious to the user that they can interact with the chart. In this article, we will explore how to modify the ECharts cursor to display a "move" background when a user hovers over the chart.

Understanding the ECharts Cursor

The ECharts cursor is controlled by the cursor option in the chart's configuration object. This option can be set to a string value that specifies the type of cursor to display. For example, setting cursor to "crosshair" will display a crosshair cursor when the user hovers over the chart.

However, the cursor option does not provide a way to display a custom cursor image or background. To achieve this, we need to use a combination of CSS and JavaScript.

Creating a Custom Cursor Background

To create a custom cursor background, we can use CSS to define a new cursor style and then apply it to the chart container using JavaScript. Here's an example:

/* Define the custom cursor style */.custom-cursor { cursor: url(/path/to/cursor.png), auto; width: 32px; height: 32px; background-color: rgba(255, 255, 255, 0.8); border-radius: 50%; position: absolute; top: -16px; left: -16px; pointer-events: none;}/* Apply the custom cursor style to the chart container */const chartContainer = document.getElementById("chart-container");chartContainer.style.cursor = "none";chartContainer.addEventListener("mousemove", (event) => { const cursor = document.createElement("div"); cursor.className = "custom-cursor"; cursor.style.left = event.clientX + "px"; cursor.style.top = event.clientY + "px"; chartContainer.appendChild(cursor);});chartContainer.addEventListener("mouseleave", () => { const cursor = document.querySelector(".custom-cursor"); if (cursor) { cursor.remove(); }});

In this example, we define a new CSS class called custom-cursor that specifies the appearance of the custom cursor. We then apply this class to a new div element that we create and position at the current mouse position using JavaScript.

Note that we set the pointer-events property of the custom-cursor class to none. This ensures that the custom cursor does not interfere with the user's ability to interact with the chart.

Modifying the ECharts Cursor on Hover

Now that we have created a custom cursor, we can modify the ECharts cursor to display a "move" background when the user hovers over the chart. To do this, we can use the mouseover and mouseout events of the chart's series objects.

// Modify the ECharts cursor on hovermyChart.on("mouseover", (params) => { if (params.seriesType === "line") { myChart.setOption({ series: { [params.seriesIndex]: { cursor: "move", }, }, }); }});myChart.on("mouseout", (params) => { if (params.seriesType === "line") { myChart.setOption({ series: { [params.seriesIndex]: { cursor: "default", }, }, }); 

In this example, we use the mouseover and mouseout events to modify the cursor option of the series object that the user is hovering over. When the user hovers over a line series, we set the cursor option to "move" to display the "move" background. This creates the illusion that the user is dragging the line series around the chart.

• ECharts provides a simple cursor that changes shape depending on the user's interaction with the chart.
• To modify the ECharts cursor, we can use a combination of CSS and JavaScript to create a custom cursor and modify the chart's cursor option on hover.
• By setting the cursor option of a series object to "move", we can display a "move" background when the user hovers over the series.

References

• ECharts Documentation: https://echarts.apache.org/en/option.html#cursor

• MDN Web Docs - CSS Cursors: https://developer.mozilla.org/en-US/docs/Web/CSS/cursor

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