Canvas-2D-Context-API-Primer/doubleBuff.html at master · rroa/Canvas-2D-Context-API-Primer · GitHub

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<!--
To change this template use Tools | Templates.
-->
<!DOCTYPE html>
<html>
<head>
    <title>Double Buffering</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=1024" />
    <meta name="apple-mobile-web-app-capable" content="yes" />
    <!--SCRIPTS-->
    <script type="text/javascript">
        function draw() {
            var canvas1 = document.getElementById('frontBuffer');
            var canvas2 = document.getElementById('backBuffer');

            // Get a reference to the drawing contexts
            var ctx1 = canvas1.getContext('2d');
            var ctx2 = canvas2.getContext('2d');

            var colors = [ "#01C001", "#0152D8", "#E46F0F", "#868686", "#850065", "#FF0000" ];
            var colorIndex = 0;

            (function drawFrame(time) {
                if( colorIndex >= colors.length ){
                    colorIndex = 0;
                }
                //window.requestAnimationFrame(drawFrame);
                ctx1.drawImage(canvas2,0,0);
                ctx2.fillStyle = colors[ colorIndex ];
                ctx2.fillRect(10,10,200,200);
                ctx2.fillStyle = "#000";
                ctx2.font = "italic 200 100px/2 Unknown Font, sans-serif"
                ctx2.fillText(colorIndex, 80, 140);
                colorIndex++;

                window.setTimeout(drawFrame, 1000);
            })();
        }
    </script>
</head>
<body onload="draw();">
    <div style="width:600px">
        <div id="back" style="width:50%;float:left;">
            <h1>BACK BUFFER</h1>
            <canvas id="backBuffer" width="300" height="300"></canvas>
        </div>
        <div id="front" style="width:50%;float:left;">
            <h1>FRONT BUFFER</h1>
            <canvas id="frontBuffer" width="300" height="300"></canvas>
        </div>
    </div>
</body>
</html>