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html 代码
<!DOCTYPE html>
<html>
<head>
<meta charset=”UTF-8″ />
<title>HTML5 Canvas放射线动画</title>
<style>
body {
background: #000;
overflow: hidden;
margin: 0;
padding: 0;
}
canvas {
width: 45%;
margin: 5% 30%;
}
</style>
</head>
<body>
<canvas id=”canv” width=”600″ height=”600″></canvas>
<script type=”text/javascript”>
var c
var $
var w = 600
var h = 600
constant = 15
var rad = 300
var timeout = 0
c = document.getElementById(‘canv’)
$ = c.getContext(‘2d’)
drawLines()
function drawLines() {
$.fillRect(0, 0, w, h)
$.translate(w / 2, h / 2)
for (var i = 0; i < 25; i++) {
for (var n = -45; n <= 45; n += constant) {
setTimeout(‘draw(‘ + n + ‘);’, 100 * timeout)
timeout++
}
}
}
function draw(n) {
$.beginPath()
$.moveTo(0, rad)
var radians = (Math.PI / 180) * n
var x =
(rad * Math.sin(radians)) / Math.sin(Math.PI / 2 – radians)
$.lineTo(x, 0)
if (Math.abs(n) == 45) {
$.strokeStyle = rndColor()
$.lineWidth = 2
} else if (n == 0) {
$.strokeStyle = ‘rgb(200,200,200)’
$.lineWidth = 0.5
} else {
$.strokeStyle = ‘rgb(110,110,110)’
$.lineWidth = 0.5
}
$.stroke()
$.rotate((Math.PI / 180) * 15)
}
function rndColor() {
var r = (255 * Math.random()) | 0,
g = (255 * Math.random()) | 0,
b = (255 * Math.random()) | 0
return ‘rgb(‘ + r + ‘,’ + g + ‘,’ + b + ‘)’
}
</script>
</body>
</html>
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