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.
New HTML datagrid
In the April 2025 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 6.22, 24th June 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.
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.The clip function
The clip function can be used when you want to restrict any drawing to a particular area of the canvas. You draw a path without stroking or filling it, call the clip function and then any further drawing will be restricted to that area. There is (currently) no resetClip function so you need to save the state of the canvas before you clip it and then restore it when you're finished - as the example shows.
In the latest canvas specification you can also give the function a Path2D object to clip to which specifies the clipping area. This isn't implemented in most browsers yet though.
Arguments to the function
-
Optionally you can specify a Path2D object to be clipped to. If not
given the default path is clipped to.
Clip to the default path:context.clip();
Clip to the given Path2D object:context.clip(path);
An example
<script> window.onload = function () { var canvas = document.getElementById("cvs"); var context = canvas.getContext('2d'); context.save(); context.beginPath(); context.rect(50,50,50,50); context.clip(); // Because the canvas is currently clipped only part of the rectangle is drawn on the canvas context.fillRect(0,0,600,250); context.restore(); } </script>