A bar chart with horizontal gradients

This bar chart draws the chart then uses the coordinates of the bars to create gradients (each is specific to a bar), changes the colors to the gradients and finally redraws the chart.

This goes in the documents header:

<script src="RGraph.common.core.js"></script>
<script src="RGraph.common.dynamic.js"></script>
<script src="RGraph.bar.js"></script>

Put this where you want the chart to show up:

<canvas id="cvs" width="600" height="250">
    [No canvas support]
</canvas>

This is the code that generates the chart:

<script>
    window.onload = function ()
    {
        var bar = new RGraph.Bar({
            id: 'cvs',
            data: [4,8,5,3,4,6,8],
            options: {
                labels: ['Mon','Tue','Wed','Thu','Fri','Sat','Sun'],
                colorsSequential: true,
                shadow: true,
                shadowColor: '#999',
                shadowOffsetx: 0,
                shadowOffsety: 0,
                shadowBlur: 15,
                strokestyle: 'rgba(0,0,0,0)',
                backgroundGridAutofitNumvlines: 7,
                noyaxis: true,
                textAccessible: true
            }
        }).draw()


        /**
        * Now the chart has been drawn use the coords to create some appropriate gradients
        */
        var colors = [];

        for(var i=0; i<bar.coords.length; ++i) {
            // Because it's a horizontal gradient the Y coords don't matter
            var x1 = bar.coords[i][0];
            var y1 = 0;
            var x2 = bar.coords[i][0] + bar.coords[i][2];
            var y2 = 0;
            
            colors[i] = RGraph.linearGradient(bar, x1, y1, x2, y2, '#c00','red');
        }

        bar.set('colors', colors);
        RGraph.clear(bar.canvas);
        RGraph.redraw();
    };
</script>