This is the single canvas version of this demo that only uses a single canvas. The background rotates and the Bar chart is drawn on top. Because of the constant updating it's not conducive to interactive features - for that you'll want the two canvas version (bar-rotating-background-dual-canvas.html).
This goes in the documents header:<script src="RGraph.common.core.js"></script> <script src="RGraph.bar.js"></script>Put this where you want the chart to show up:
<canvas id="cvs" width="750" height="250">[No canvas support]</canvas>This is the code that generates the chart: