About
RGraph is a JavaScript charts library based on
HTML5 SVG and canvas. RGraph is mature (over 18 years
old) and has a wealth of features making it an ideal
choice to use for showing charts on your website.
Version 7.20
Version 7.20 (released in June 2026) is the
latest version of RGraph and the major change in
this version is an update to the default values
of properties making for better looking charts without
having to set any properties.
Read more about this and other changes in
the changelog.
Download
Get the latest version of RGraph (version 7.20, 9th June 2026) 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.
Latest forum posts
These are the latest support forum posts that have been
posted or updated.
9th June, Richard
New version of RGraph: version 7.20
3rd June, Patrick
Question about installing RGraph
1st June, Ouja
How do I add a click event to a bar in my Bar chart?
8th May, Anthony Kuma
Does the SVG Line chart have outofbounds functionality?
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 getImageData function
The getImageData function allows to retrieve an ImageData object from your canvas. This allows you to manipulate it as you wish and then you can add it back onto the canvas with the putImageData function (reference page for the putImageData function). You can pass it the X/Y/W/H that you want to fetch as arguments.
Arguments to the function
- The X coordinate at which to fetch data
- The Y coordinate at which to fetch data
- The width to fetch
- The height to fetch
An example
<script>
window.onload = function ()
{
var canvas = document.getElementById('cvs');
var context = canvas.getContext('2d');
// Fetches image data from the canvas
var imgData = context.getImageData(0,0,600,250);
}
</script>