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.The translate function
The translate function adjusts the coordinate system of the canvas. Normally
the [0, 0] coordinates are in the top left
corner, but by using the translate function you can move them to wherever you wish.
To move things back and up the
numbers can be negative. Translating is affected by the use of the save
and restore functions so if necessary you
can save, translate, restore - and the
state of the canvas will be as it was before you saved.
Arguments to the function
- Number of pixels to move in the horizontal direction (can be negative)
- Number of pixels to move in the vetrical direction (can be negative)
An example
You can use the function like this:
<script>
window.onload = function ()
{
var canvas = document.getElementById("cvs");
var context = canvas.getContext('2d');
// After the translate the [0,0] coordinates will actually be 50 pixels down and 50
// pixels to the right of where they would be normally
context.translate(50, 50);
context.beginPath();
context.moveTo(100, 100);
context.lineTo(200, 200);
context.stroke();
}
</script>