programming-examples/html/Rendering_Techniques/09-gradient-fill-radial.html

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2019-11-15 12:59:38 +01:00
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Gradient Fill Radial</title>
<link rel="stylesheet" href="../include/style.css">
</head>
<body>
<header>
Example from <a href="http://amzn.com/1430236655?tag=html5anim-20"><em>Foundation HTML5 Animation with JavaScript</em></a>
</header>
<canvas id="canvas" width="400" height="400"></canvas>
<script>
window.onload = function () {
var canvas = document.getElementById('canvas'),
context = canvas.getContext('2d'),
c1 = {x: 150, y: 150, radius: 0}, //gradient start circle
c2 = {x: 150, y: 150, radius: 50}, //gradient end circle
gradient = context.createRadialGradient(c1.x, c1.y, c1.radius,
c2.x, c2.y, c2.radius);
//all black alpha blend
gradient.addColorStop(0, "#000000");
gradient.addColorStop(1, "rgba(0, 0, 0, 0)"); //alpha required
context.fillStyle = gradient;
context.fillRect(100, 100, 100, 100);
};
</script>
</body>
</html>