一个超炫HTML5效果代码

文章由LinuxBoy分享于2019-04-01 04:04:21热评（52）

一个超炫HTML5效果代码

一个超炫HTML5效果实现代码。

需要用Chrome 或者Opera，Firefox，浏览器查看。

效果图如下：

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
<title>star</title>
<script type="text/javascript">
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>
</head>

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一个超炫HTML5效果代码