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  • HTML5 CSS3银河系星空闪耀网页背景动画特效

    HTML5 CSS3银河系星空闪耀网页背景动画特效,运行本效果后,一幅像银河系的星空图展现眼前,远处星空闪耀,星空整体上同样也具有动画效果,可很好的应用于网页背景中,本背景动画的生成依赖Canvas技术,运行时请选择支持Canvas技术的浏览器,IE就免谈了,推荐Chrome。提示:若不能运行,请将代码保存到本地HTML文件中,然后使用Chrome打开。

    【源代码展示】

    <!doctype html>
    <html>
    <head>
    <meta charset="utf-8">
    <title>HTML5 Canvas全屏背景动画</title>
    <style>
    body {
      background: #060e1b;
      overflow: hidden;
    }
    .codrops-demos {
        font-size: 0.8em;
        text-align:center;
        position:absolute;
        z-index:99;
        width:96%;
    }
    .codrops-demos a {
        display: inline-block;
        margin: 0.35em 0.1em;
        padding: 0.5em 1.2em;
        outline: none;
        text-decoration: none;
        text-transform: uppercase;
        letter-spacing: 1px;
        font-weight: 700;
        border-radius: 2px;
        font-size: 110%;
        border: 2px solid transparent;
        color:#fff;
    }
    .codrops-demos a:hover,
    .codrops-demos a.current-demo {
        border-color: #383a3c;
    }
    </style>
    </head>
    <body>
    <canvas id="canvas"></canvas>
    <script>
    "use strict";
    var canvas = document.getElementById('canvas'),
      ctx = canvas.getContext('2d'),
      w = canvas.width = window.innerWidth,
      h = canvas.height = window.innerHeight,
      hue = 217,
      stars = [],
      count = 0,
      maxStars = 1400;
    var canvas2 = document.createElement('canvas'),
        ctx2 = canvas2.getContext('2d');
        canvas2.width = 100;
        canvas2.height = 100;
    var half = canvas2.width/2,
        gradient2 = ctx2.createRadialGradient(half, half, 0, half, half, half);
        gradient2.addColorStop(0.025, '#fff');
        gradient2.addColorStop(0.1, 'hsl(' + hue + ', 61%, 33%)');
        gradient2.addColorStop(0.25, 'hsl(' + hue + ', 64%, 6%)');
        gradient2.addColorStop(1, 'transparent');
        ctx2.fillStyle = gradient2;
        ctx2.beginPath();
        ctx2.arc(half, half, half, 0, Math.PI * 2);
        ctx2.fill();
    // End cache
    function random(min, max) {
      if (arguments.length < 2) {
        max = min;
        min = 0;
      }
      if (min > max) {
        var hold = max;
        max = min;
        min = hold;
      }
      return Math.floor(Math.random() * (max - min + 1)) + min;
    }
    var Star = function() {
      this.orbitRadius = random(w / 2 - 50);
      this.radius = random(100, this.orbitRadius) / 10;
      this.orbitX = w / 2;
      this.orbitY = h / 2;
      this.timePassed = random(0, maxStars);
      this.speed = random(this.orbitRadius) / 900000;
      this.alpha = random(2, 10) / 10;
      count++;
      stars[count] = this;
    }
    Star.prototype.draw = function() {
      var x = Math.sin(this.timePassed + 1) * this.orbitRadius + this.orbitX,
          y = Math.cos(this.timePassed) * this.orbitRadius/2 + this.orbitY,
          twinkle = random(10);
      if (twinkle === 1 && this.alpha > 0) {
        this.alpha -= 0.05;
      } else if (twinkle === 2 && this.alpha < 1) {
        this.alpha += 0.05;
      }
      ctx.globalAlpha = this.alpha;
        ctx.drawImage(canvas2, x - this.radius / 2, y - this.radius / 2, this.radius, this.radius);
      this.timePassed += this.speed;
    }
    for (var i = 0; i < maxStars; i++) {
      new Star();
    }
    function animation() {
        ctx.globalCompositeOperation = 'source-over';
        ctx.globalAlpha = 0.8;
        ctx.fillStyle = 'hsla(' + hue + ', 64%, 6%, 1)';
        ctx.fillRect(0, 0, w, h)
      ctx.globalCompositeOperation = 'lighter';
      for (var i = 1, l = stars.length; i < l; i++) {
        stars[i].draw();
      };
      window.requestAnimationFrame(animation);
    }
    animation();
    </script>
    </body>
    </html>

    ----------------------------------------------------------------------------------------------------------------------------------------------感谢观看!期待您的下次光临!

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  • 原文地址:https://www.cnblogs.com/varchar-pig/p/14224566.html
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