42 lines
1.2 KiB
HTML
42 lines
1.2 KiB
HTML
|
<!doctype html>
|
||
|
|
<html>
|
||
|
|
<head>
|
||
|
|
<meta charset="utf-8">
|
||
|
|
<title>Curve Through Point</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>
|
||
|
|
window.onload = function () {
|
||
|
|
var canvas = document.getElementById('canvas'),
|
||
|
|
context = canvas.getContext('2d'),
|
||
|
|
mouse = utils.captureMouse(canvas),
|
||
|
|
x0 = 100,
|
||
|
|
y0 = 200,
|
||
|
|
x2 = 300,
|
||
|
|
y2 = 200;
|
||
|
|
|
||
|
|
canvas.addEventListener('mousemove', function () {
|
||
|
|
context.clearRect(0, 0, canvas.width, canvas.height);
|
||
|
|
|
||
|
|
var x1 = mouse.x * 2 - (x0 + x2) / 2,
|
||
|
|
y1 = mouse.y * 2 - (y0 + y2) / 2;
|
||
|
|
|
||
|
|
//curve through mouse
|
||
|
|
context.beginPath();
|
||
|
|
context.moveTo(x0, y0);
|
||
|
|
context.quadraticCurveTo(x1, y1, x2, y2);
|
||
|
|
context.stroke();
|
||
|
|
}, false);
|
||
|
|
};
|
||
|
|
</script>
|
||
|
|
</body>
|
||
|
|
</html>
|