来源:flash,as,js兴趣爱好者html5 canvas动画之彩色画笔 html5 canvas动画之彩色画笔
<!--代码开始-->
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
<title>html5超炫动画</title>
<script type="text/javascript">
/*
Breathing Galaxies (1020 bytes)
--------------------------------
window.onload=function(){C=Math.cos;S=Math.sin;U=0;w=window;j=document;d=j.getElementById("c");c=d.getContext("2d");W=d.width=w.innerWidth;H=d.height=w.innerHeight;c.fillRect(0,0,W,H);c.globalCompositeOperation="lighter";c.lineWidth=0.2;c.lineCap="miter";var e=0,h=0;d.onmousemove=function(k){if(window.T){if(D==9){D=Math.random()*15;f(1)}clearTimeout(T)}X=k.pageX;Y=k.pageY;a=0;b=0;A=X,B=Y;R=(k.pageX/W*999>>0)/999;r=(k.pageY/H*999>>0)/999;U=k.pageX/H*360>>0;D=9;g=360*Math.PI/180;T=setInterval(f=function(l){c.save();c.globalCompositeOperation="source-over";if(!l){c.fillStyle="rgba(0,0,0,0.01)";c.fillRect(0,0,W,H)}c.restore();i=25;while(i--){c.beginPath();if(D>450||e){if(!e){e=1}if(D<0.1){e=0}h-=g;D-=0.1}if(!e){h+=g;D+=0.1}q=(R/r-1)*h;x=(R-r)*C(h)+D*C(q)+(A+(X-A)*(i/25))+(r-R);y=(R-r)*S(h)-D*S(q)+(B+(Y-B)*(i/25));if(a){c.moveTo(a,b);c.lineTo(x,y)}c.strokeStyle="hsla("+(U%360)+",100%,50%,0.75)";c.stroke();a=x;b=y}U-=0.5;A=X;B=Y},16)};j.onkeydown=function(k){a=b=0;R+=0.05};d.onmousemove({pageX:300,pageY:290})};
*/
window.onload = function () {
C = Math.cos; // cache Math objects
S = Math.sin;
U = 0;
w = window;
j = document;
d = j.getElementById("c");
c = d.getContext("2d");
W = d.width = w.innerWidth;
H = d.height = w.innerHeight;
c.fillRect(0, 0, W, H); // resize <canvas> and draw black rect (default)
c.globalCompositeOperation = "lighter"; // switch to additive color application
c.lineWidth = 0.2;
c.lineCap = "round";
var bool = 0,
t = 0; // theta
d.onmousemove = function (e) {
if(window.T) {
if(D==9) { D=Math.random()*15; f(1); }
clearTimeout(T);
}
X = e.pageX; // grab mouse pixel coords
Y = e.pageY;
a=0; // previous coord.x
b=0; // previous coord.y
A = X, // original coord.x
B = Y; // original coord.y
R=(e.pageX/W * 999>>0)/999;
r=(e.pageY/H * 999>>0)/999;
U=e.pageX/H * 360 >>0;
D=9;
g = 360 * Math.PI / 180;
T = setInterval(f = function (e) { // start looping spectrum
c.save();
c.globalCompositeOperation = "source-over"; // switch to additive color application
if(e!=1) {
c.fillStyle = "rgba(0,0,0,0.02)";
c.fillRect(0, 0, W, H); // resize <canvas> and draw black rect (default)
}
c.restore();
i = 25; while(i --) {
c.beginPath();
if(D > 450 || bool) { // decrease diameter
if(!bool) { // has hit maximum
bool = 1;
}
if(D < 0.1) { // has hit minimum
bool = 0;
}
t -= g; // decrease theta
D -= 0.1; // decrease size
}
if(!bool) {
t += g; // increase theta
D += 0.1; // increase size
}
q = (R / r - 1) * t; // create hypotrochoid from current mouse position, and setup variables (see: http://en.wikipedia.org/wiki/Hypotrochoid)
x = (R - r) * C(t) + D * C(q) + (A + (X - A) * (i / 25)) + (r - R); // center on xy coords
y = (R - r) * S(t) - D * S(q) + (B + (Y - B) * (i / 25));
if (a) { // draw once two points are set
c.moveTo(a, b);
c.lineTo(x, y)
}
c.strokeStyle = "hsla(" + (U % 360) + ",100%,50%,0.75)"; // draw rainbow hypotrochoid
c.stroke();
a = x; // set previous coord.x
b = y; // set previous coord.y
}
U -= 0.5; // increment hue
A = X; // set original coord.x
B = Y; // set original coord.y
}, 16);
}
j.onkeydown = function(e) { a=b=0; R += 0.05 }
d.onmousemove({pageX:300, pageY:290})
}
</script>
<style>
body { margin: 0; overflow: hidden; }
div { padding: 1px 5px; background: #333; position: absolute; z-index: 2; color: #555; font-family: arial; }
a { color: #ccf }
a:hover { color: #ff0000 }
</style>
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var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-400768-7']);
_gaq.push(['_trackPageview']);
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var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
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<div><a href="http://mudcu.be/">mudcu.be</a> › <a href="http://mudcu.be/journal/">journal</a> › <a href="http://mudcube7.blogspot.com/2010/08/what-can-1kb-of-javascript-do.html">JS1k: What can 1kb of Javascript do?</a></div>
<div id="text"></div>
<canvas id="c"></canvas>
</body>
</html>
