Tooltip in EJ2 JavaScript Heatmap chart control

18 Apr 202316 minutes to read

Tooltip is used to provide the details of the heat map cell, and this can be displayed, while hovering the cursor over the cell or performing tap action in touch devices.

Default Tooltip

You can enable the tooltip by setting the showTooltip property to true and injecting the Tooltip module using the HeatMap.Inject(Tooltip).

var heatmapData = [
    [0.72, 0.71, 0.71, 0.67, 0.72, 0.53, 0.53, 0.56, 0.58, 0.56],
    [2.28, 2.29, 2.09, 1.84, 1.64, 1.49, 1.49, 1.39, 1.32, 1.23],
    [2.02, 2.17, 2.30, 2.39, 2.36, 2.52, 2.62, 2.57, 2.57, 2.74],
    [3.21, 3.26, 3.45, 3.47, 3.42, 3.34, 3.14, 2.83, 2.64, 2.61],
    [3.22, 3.13, 3.04, 2.95, 2.69, 2.49, 2.27, 2.18, 2.06, 1.87],
    [3.30, 3.39, 3.40, 3.48, 3.60, 3.67, 3.73, 3.79, 3.79, 4.07],
    [5.80, 5.74, 5.64, 5.44, 5.18, 5.08, 5.07, 5.00, 5.35, 5.47],
    [6.91, 7.40, 8.13, 8.80, 9.04, 9.24, 9.43, 9.35, 9.49, 9.69]
];

var heatmap = new ej.heatmap.HeatMap({
      titleSettings: {
            text: 'Crude Oil Production of Non-OPEC Countries (in Million barrels per day)',
            textStyle: {
                size: '15px',
                fontWeight: '500',
                fontStyle: 'Normal',
                fontFamily: 'Segoe UI'
            }
        },
        xAxis: {
            labels: ['Canada', 'China', 'Egypt', 'Mexico', 'Norway', 'Russia', 'UK', 'USA']
        },
        yAxis: {
             labels: ['2000', '2001', '2002', '2003', '2004', '2005', '2006', '2007', '2008', '2009', '2010'],
        },
        cellSettings: {
            showLabel: false,
        },
        dataSource: heatmapData, 
        showTooltip:true
});
heatmap.appendTo('#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 HeatMap</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    
    
<script src="https://cdn.syncfusion.com/ej2/28.2.3/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    
    <div id="container">
        <div id="element"></div>
    </div>


<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

Tooltip template

In heat map, you can customize the tooltip using the tooltipRender client-side event.

var heatmapData = [
    [0.72, 0.71, 0.71, 0.67, 0.72, 0.53, 0.53, 0.56, 0.58, 0.56],
    [2.28, 2.29, 2.09, 1.84, 1.64, 1.49, 1.49, 1.39, 1.32, 1.23],
    [2.02, 2.17, 2.30, 2.39, 2.36, 2.52, 2.62, 2.57, 2.57, 2.74],
    [3.21, 3.26, 3.45, 3.47, 3.42, 3.34, 3.14, 2.83, 2.64, 2.61],
    [3.22, 3.13, 3.04, 2.95, 2.69, 2.49, 2.27, 2.18, 2.06, 1.87],
    [3.30, 3.39, 3.40, 3.48, 3.60, 3.67, 3.73, 3.79, 3.79, 4.07],
    [5.80, 5.74, 5.64, 5.44, 5.18, 5.08, 5.07, 5.00, 5.35, 5.47],
    [6.91, 7.40, 8.13, 8.80, 9.04, 9.24, 9.43, 9.35, 9.49, 9.69]
];

var heatmap = new ej.heatmap.HeatMap({
      titleSettings: {
            text: 'Crude Oil Production of Non-OPEC Countries (in Million barrels per day)',
            textStyle: {
                size: '15px',
                fontWeight: '500',
                fontStyle: 'Normal',
                fontFamily: 'Segoe UI'
            }
        },
        xAxis: {
            labels: ['Canada', 'China', 'Egypt', 'Mexico', 'Norway', 'Russia', 'UK', 'USA']
        },
        yAxis: {
             labels: ['2000', '2001', '2002', '2003', '2004', '2005', '2006', '2007', '2008', '2009', '2010'],
        },
        cellSettings: {
            showLabel: false,
        },
        dataSource: heatmapData, 
        showTooltip:true,  
        tooltipRender: function (args) {
            args.content = ['In ' + args.yLabel + ', the ' + args.xLabel + ' produced ' + args.value + ' million barrels per day'];
        },
});
heatmap.appendTo('#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 HeatMap</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    
    
<script src="https://cdn.syncfusion.com/ej2/28.2.3/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    
    <div id="container">
        <div id="element"></div>
    </div>


<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

Customize the appearance of Tooltip

The fill and border properties are used to customize the background color and border of the tooltip respectively. The textStyle property in the tooltip is used to customize the font of the tooltip text.

var heatmapData = [
    [0.72, 0.71, 0.71, 0.67, 0.72, 0.53, 0.53, 0.56, 0.58, 0.56],
    [2.28, 2.29, 2.09, 1.84, 1.64, 1.49, 1.49, 1.39, 1.32, 1.23],
    [2.02, 2.17, 2.30, 2.39, 2.36, 2.52, 2.62, 2.57, 2.57, 2.74],
    [3.21, 3.26, 3.45, 3.47, 3.42, 3.34, 3.14, 2.83, 2.64, 2.61],
    [3.22, 3.13, 3.04, 2.95, 2.69, 2.49, 2.27, 2.18, 2.06, 1.87],
    [3.30, 3.39, 3.40, 3.48, 3.60, 3.67, 3.73, 3.79, 3.79, 4.07],
    [5.80, 5.74, 5.64, 5.44, 5.18, 5.08, 5.07, 5.00, 5.35, 5.47],
    [6.91, 7.40, 8.13, 8.80, 9.04, 9.24, 9.43, 9.35, 9.49, 9.69]
];

var heatmap = new ej.heatmap.HeatMap({
      titleSettings: {
            text: 'Crude Oil Production of Non-OPEC Countries (in Million barrels per day)',
            textStyle: {
                size: '15px',
                fontWeight: '500',
                fontStyle: 'Normal',
                fontFamily: 'Segoe UI'
            }
        },
        xAxis: {
            labels: ['Canada', 'China', 'Egypt', 'Mexico', 'Norway', 'Russia', 'UK', 'USA']
        },
        yAxis: {
             labels: ['2000', '2001', '2002', '2003', '2004', '2005', '2006', '2007', '2008', '2009', '2010'],
        },
        paletteSettings: {
            palette: [{ color: '#F0ADCE' },
            { color: '#19307B' }
            ]
        },
        dataSource: heatmapData, 
        showTooltip:true,
        cellSettings: {
            showLabel: false,
        },
        tooltipSettings: {
            fill: '#696295',
            textStyle: {
                color: '#FFFFFF',
                size: '12px'
            },
             border: {
                width: 2,
                color: '#F0C27B'
            }
        },  
        tooltipRender: function (args) {
            args.content = ['In ' + args.yLabel + ', the ' + args.xLabel + ' produced ' + args.value + ' million barrels per day'];
        },
});
heatmap.appendTo('#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 HeatMap</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    
    
<script src="https://cdn.syncfusion.com/ej2/28.2.3/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    
    <div id="container">
        <div id="element"></div>
    </div>


<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

Note: To use tooltip feature, we need to inject Tooltip using HeatMap.Inject(Tooltip).