css/css-paint-api/paint2d-composite-ref.html

<!DOCTYPE html>
<html>
<head>
<style>
    canvas { display: inline-block; }
</style>
</head>
<body>
<canvas id="source-over" width="80" height="80"></canvas>
<canvas id="source-in" width="80" height="80"></canvas>
<canvas id="source-out" width="80" height="80"></canvas>
<canvas id="source-atop" width="80" height="80"></canvas>
<br>
<canvas id="destination-over" width="80" height="80"></canvas>
<canvas id="destination-in" width="80" height="80"></canvas>
<canvas id="destination-out" width="80" height="80"></canvas>
<canvas id="destination-atop" width="80" height="80"></canvas>
<br>
<canvas id="lighter" width="80" height="80"></canvas>
<canvas id="xor" width="80" height="80"></canvas>
<script>
var compositeOps = [
    'source-over',
    'source-in',
    'source-out',
    'source-atop',
    'destination-over',
    'destination-in',
    'destination-out',
    'destination-atop',
    'lighter',
    'xor'
];

for (var i = 0; i < compositeOps.length; i++) {
    var op = compositeOps[i];
    var ctx = document.getElementById(op).getContext('2d');
    ctx.fillStyle = 'red';
    ctx.fillRect(5, 5, 40, 40);

    ctx.globalCompositeOperation = op;

    ctx.fillStyle = 'deepskyblue';
    ctx.beginPath();
    ctx.arc(45,45,20,0,Math.PI*2,true);
    ctx.fill();
}
</script>
</body>
</html>