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<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Cosines 1</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>
<aside>Move mouse on canvas element.</aside>
<script src="../include/utils.js"></script>
<script src="./classes/segment.js"></script>
<script>
window.onload = function () {
var canvas = document.getElementById('canvas'),
context = canvas.getContext('2d'),
mouse = utils.captureMouse(canvas),
segment0 = new Segment(100, 20),
segment1 = new Segment(100, 20);
segment1.x = canvas.width / 2;
segment1.y = canvas.height / 2;
(function drawFrame () {
window.requestAnimationFrame(drawFrame, canvas);
context.clearRect(0, 0, canvas.width, canvas.height);
var dx = mouse.x - segment1.x,
dy = mouse.y - segment1.y,
dist = Math.sqrt(dx * dx + dy * dy),
a = 100,
b = 100,
c = Math.min(dist, a + b),
B = Math.acos((b * b - a * a - c * c) / (-2 * a * c)),
C = Math.acos((c * c - a * a - b * b) / (-2 * a * b)),
D = Math.atan2(dy, dx),
E = D + B + Math.PI + C;
segment1.rotation = (D + B);
var target = segment1.getPin();
segment0.x = target.x;
segment0.y = target.y;
segment0.rotation = E;
segment0.draw(context);
segment1.draw(context);
}());
};
</script>
</body>
</html>