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 datagrid in v6.21
In version 6.21 a new datagrid object has been 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 6.21, 10th April 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.Radial gradients
Radial gradients can be used in place of regular color definitions to add
gradients to your canvas. They're different to linear
gradients because they're circular in nature, as the name suggests. They're
specified using
the gradient api and can consist of multiple colors. The
createRadialGradient function is used to create the gradient and then
the addColorStop function is used to add points along the
gradient - similar to linear gradients.
Arguments to the function
- The X1 coordinate
- The Y1 coordinate
- The R1 coordinate (radius)
- The X2 coordinate
- The Y2 coordinate
- The R2 coordinate (radius)
An example
<script>
window.onload = function ()
{
var canvas = document.getElementById('cvs');
var context = canvas.getContext('2d');
// Create the gradient
var gradient = context.createRadialGradient(175,75,0,175,75,100);
gradient.addColorStop(0, 'white');
gradient.addColorStop(1, 'rgb(255,125,125)');
context.beginPath();
context.fillStyle = gradient
context.arc(125,125,100,0,Math.PI * 2, false);
context.fill();
}
</script>
See also