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.net Powerful JavaScript charts
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.

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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.

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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.

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Latest forum posts
These are the latest support forum posts that have been posted or updated.


12th June, Marco
Should I use SVG or canvas for the charts on my website?
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?


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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.

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Drawing a curved image on canvas using clipping

Written by Richard Heyes, RGraph author, on 2nd December 2023

Here's an example of a curved image - which is not terribly difficult to achieve but it can't be done by just calling a function or setting an option - but clipping to the rescue! This first came to my attention because of this article: https://programming.bogdanbucur.eu/drawing-a-curved-image-with-a-html5-canvas-and-javascript/ which uses a different method but this method uses clipping (read the reference page for the clip function here: https://www.rgraph.net/canvas/reference/clip.html). The code for the example is shown below and the comments in the code should provide you with some information about what it's doing.

    >script<
        // Get hold of the context so that we can draw
        context = document.getElementById('cvs').getContext('2d');

        //
        // Load the image first. When it has loaded call the
        // draw() function to draw the image. Then add some
        // text.
        //
        var img = new Image();
        img.src = '/images/page-blog-curved-image.png';
        img.onload = function ()
        {
            // When the image has loaded - call the draw()
            // function that draws the image on to the
            // canvas
            draw();

            //
            // Draw the text that you can see beneath the image.
            // Despite being higher up in the code than the draw()
            // function, this text is actually drawn last.
            //
            context.font      = '26pt Arial';
            context.textAlign = 'center';
            context.fillText('A curved image!', 300,230);
        };




        //
        // This is the main draw function that draws on the
        // canvas
        //
        function draw()
        {
            //
            // Save the canvas state before clipping so that
            // it be reset after drawing has finished
            //
            context.save();

            //
            // Start a new path and draw the outline of the curved shape.
            // This shape will not be immediately drawn on to the canvas -
            // first we're going to clip to the shape and then draw the
            // image. So the image will be constrained to the area within
            // the shape. Only after the image has been drawn will the
            // path that we're drawing here be stroked to the canvas in
            // black (producing the black outline that you can see around
            // the image).
            //
            context.beginPath();
            context.moveTo(100,200);
            context.lineTo(100,50);
            context.quadraticCurveTo(300, 0, 500, 50);
            context.lineTo(500,200);
            context.quadraticCurveTo(300, 150, 100, 200);
            context.closePath();
            context.clip();

            //
            // Draw the image
            //
            context.drawImage(img,0,-40);
            
            //
            // Restore the canvas state now that the
            // image has been drawn (effectively
            // turning off clipping.
            //
            context.restore();

            //
            // Now that clipping has been turned off, stroke
            // the path that was first made (ie what was defined
            // to be the clip path to make the outline)
            //
            context.lineWidth = 3;
            context.stroke();
        }
    </script>