An updated version of the multi-colored Line chart demo

About

RGraph is a JavaScript charts library based on HTML5 SVG and canvas. RGraph is mature (over 17 years old) and has a wealth of features making it an ideal choice to use for showing charts on your website.

Version 7.01 released

Version 7.01 (released in October 2025) is the latest version of RGraph and now includes a new tree structure object. The accompanying Treemenu object can then turn the object into a fully dynamic tree menu. You can read the API documentation for the tree on the main API documentation page and see an example of the Treemenu feature by following this link...

New HTML datagrid

In the April 2025 (v6.21) release a new datagrid object was added. This makes it easy to add static or dynamic data tables to your pages. It can be used whether you use the canvas or SVG libraries or entirely standalone.

Download

Get the latest version of RGraph (version 7.01, 8th October 2025) from the download page. You can read the changelog here. There's also older versions available, minified files and links to cdnjs.com hosted libraries.

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License

RGraph can be used for free under the GPL or if that doesn't suit your situation there's an inexpensive (£129) commercial license available.

Here's an updated version of a demo that's already in the download archive. The colors have been changed, tickmarks added, it now uses the es6 spread operator when copying the configuration to the second chart, a key has been added and the way that the gradients are setup (using the beforedraw RGraph event). All the code for it is shown below and it should work as-is with version 6.08.

<script>

    // The data for both of the Line chart objects
    data = [8,4,6,2,1,5,3,3,4,8,9,8,4,1,3,4,7,8,8,5,6,4,1,2,3,4,2,3,1,5,3,5,1,5,6,8,7,9];
    
    // Draw a Line chart that shows the fill of the chart
    line = new RGraph.Line({
        id: 'cvs',
        data: data,
        options: {
            backgroundGrid: false,
            xaxisLabels: [
                '','Q1\n2014','',       '','Q2\n2014','',
                '','Q3\n2014','',       '','Q4\n2014','',
                '','Q1\n2015','',       '','Q2\n2015','',
                '','Q3\n2015','',       '','Q4\n2015',''
            ],
            filled: true,
            backgroundGridColor: '#ddd',
            backgroundGridVlines: false,
            backgroundGridBorder: false,
            xaxis: false,
            yaxis: false,
            spline: true,
            yaxisScaleUnitsPost: '%',
            marginLeft: 50,
            marginTop: 50,
            marginBottom: 50,
            textColor: 'gray',
            colors: ['rgba(0,0,0,0)'],
            shadow: false,
            keyLabelsSize: 16,
            linewidth: 1,
            textSize: 16,
            textFont: "'Calibri Light', sans-serif",
            events: {
                beforedraw: function (obj)
                {
                    var height = obj.canvas.height;

                    // Create the gradient that is used as the fill color
                    grad = obj.context.createLinearGradient(0,50,0,height - 50);

                    grad.addColorStop(0, '#0003');
                    grad.addColorStop(0.2, '#0003');
                    grad.addColorStop(0.2, '#f0f3');
                    grad.addColorStop(0.4, '#f0f3');
                    grad.addColorStop(0.4, '#0a03');
                    grad.addColorStop(0.6, '#0a03');
                    grad.addColorStop(0.6, '#00f3');
                    grad.addColorStop(0.8, '#00f3');
                    grad.addColorStop(0.8, '#f003');
                    grad.addColorStop(1.0, '#f003');
    
                    // Apply the gradient to the charts fill
                    obj.set({
                        filledColors: [grad]
                    });
                }
            }
        }
    }).draw();
    
    
    












    // Now create and draw the second, non-filled line that sits on
    // top of the fill.
    line2 = new RGraph.Line({
        id: 'cvs',
        data: data,
        options: {
            ...line.properties,
            filled: false,
            labels: null,
            xaxis: false,
            yaxis: false,
            yaxisLabels: false,
            backgroundGrid: false,
            tickmarksStyle: 'filledcircle',
            key: null,
            key: ['V Low','Low','Normal','High','V high'],
            keyColors: ['red','blue','#0a06','#f0f','black'],
            keyPosition: 'margin',
            keyPositionX: 65,
            keyColorShape: 'circle',
            responsive: [
                {maxWidth: null, width: 700, height: 300,options: {linewidth:2}},
                {maxWidth: 900, width: 500, height: 200,options: {linewidth:1}}
            ],
            events: {
                beforedraw: function (obj)
                {
                    var height = obj.canvas.height;

                    // Create the gradient that is used as the stroke color
                    grad = obj.context.createLinearGradient(0,50,0,height - 50);
                    grad.addColorStop(0, '#000');
                    grad.addColorStop(0.2, '#000');
                    grad.addColorStop(0.2, '#f0f');
                    grad.addColorStop(0.4, '#f0f');
                    grad.addColorStop(0.4, '#0a0');
                    grad.addColorStop(0.6, '#0a0');
                    grad.addColorStop(0.6, '#00f');
                    grad.addColorStop(0.8, '#00f');
                    grad.addColorStop(0.8, '#f00');
                    grad.addColorStop(1.0, '#f00');
        
                    obj.set({
                        colors: [grad]
                    });
                }
            }
        }
    }).draw();
</script>

Updated multi-color Line chart demo