RGraph is a JavaScript charts library based on HTML5 SVG and canvas. RGraph is mature (over 15 years old) and has a wealth of features making it an ideal choice to show charts on your website.

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Get the latest version of RGraph (version 6.17) from the download page. There's also older versions available, minified files and links to cdnjs.com hosted libraries.

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RGraph can be used for free under the GPL or if that doesn't suit your situation there's an inexpensive (£99) commercial license available.

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The createPattern function

Patterns can be created to make self-repeating fills/strokes instead of using a standard color or gradient. You can use an image as the source, or a video, or another canvas. By using an image to cover the canvas you could create realistic repeating images (eg of water or sand) from just one small image.

You don't have to use an image - other options include video and other canvas tags. This allows you to draw a pattern on one canvas and then have that repeated as a background on another tag. Alternatively, you could create a pattern out of a video (that plays in the background).

Arguments to the function

An example

    window.onload = function ()
        var canvas = document.getElementById('cvs');
        var context = canvas.getContext('2d');

        var image = new Image();
        image.src = '/images/logo.png';
        image.onload = function ()
            var pattern = context.createPattern(image, 'repeat');
            context.fillStyle = pattern;
            context.fillRect(0, 0, 600, 250);