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 use for showing charts on your website.

More »


Get the latest version of RGraph (version 6.18, 1st June 2024) 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.

More »


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.

More »

The lineCap property

The lineCap property is used to change the way that the ends of lines are drawn. The possible values are butt (default), round and square. Examples of these are shown below. Although the butt and square settings appear to be the same you should note that the square setting has an overhang whilst the butt setting does not.

Examples of the different line styles

An example

    window.onload = function ()
        var canvas  = document.getElementById("cvs");
        var context = canvas.getContext('2d');
        // Translate by half a pixel - this makes lines look crisp
        context.translate(0.5, 0.5);
        context.lineCap = 'butt';
        context.lineWidth = 25;