HTML5和Webkit实现树叶飘落动画

互联网 17-12-29

HTML5和Webkit在一起会实现什么样的动画呢？本文给大家分享一段实例代码给大家介绍基于HTML5+Webkit实现树叶飘落动画效果，需要的朋友参考下吧，希望能帮组到大家。

实现如图所示的东西效果（落叶下落）：

html代码：

<!DOCTYPE html>  <html>  <head>      <title>HTML5树叶飘落动画</title>      <meta charset="utf-8">      <meta name="viewport" content="width=500px, initial-scale=0.64">      <link rel="stylesheet" href="leaves.css" type="text/css">      <script src="leaves.js" type="text/javascript"></script>  </head>  <body>      <p id="container">          <p id="leafContainer"></p>          <p id="message">              <em>这是基于webkit的落叶动画</em>          </p>      </p>    </body>  </html>  css代码：  body{      background-color: #4E4226;  }  #container {      position: relative;      height: 700px;      width: 500px;      margin: 10px auto;      overflow: hidden;      border: 4px solid #5C090A;      background: #4E4226 url('images/backgroundLeaves.jpg') no-repeat top left;  }  #leafContainer {      position: absolute;      width: 100%;      height: 100%;  }  #message{      position: absolute;      top: 160px;      width: 100%;      height: 300px;      background:transparent url('images/textBackground.png') repeat-x center;      color: #5C090A;      font-size: 220%;      font-family: 'Georgia';      text-align: center;      padding: 20px 10px;      -webkit-box-sizing: border-box;      -webkit-background-size: 100% 100%;      z-index: 1;  }  em {      font-weight: bold;      font-style: normal;  }  #leafContainer > p {      position: absolute;      width: 100px;      height: 100px;      -webkit-animation-iteration-count: infinite;      -webkit-animation-direction: normal;      -webkit-animation-timing-function: linear;  }  #leafContainer > p > img {       position: absolute;       width: 100px;       height: 100px;       -webkit-animation-iteration-count: infinite;       -webkit-animation-direction: alternate;       -webkit-animation-timing-function: ease-in-out;       -webkit-transform-origin: 50% -100%;  }  @-webkit-keyframes fade{      0%   { opacity: 1; }      95%  { opacity: 1; }      100% { opacity: 0; }  }  @-webkit-keyframes drop{      0%   { -webkit-transform: translate(0px, -50px); }      100% { -webkit-transform: translate(0px, 650px); }  }  @-webkit-keyframes clockwiseSpin{      0%   { -webkit-transform: rotate(-50deg); }      100% { -webkit-transform: rotate(50deg); }  }  @-webkit-keyframes counterclockwiseSpinAndFlip {      0%   { -webkit-transform: scale(-1, 1) rotate(50deg); }      100% { -webkit-transform: scale(-1, 1) rotate(-50deg); }  }  js代码：  const NUMBER_OF_LEAVES = 30;  function init(){      var container = document.getElementById('leafContainer');      for (var i = 0; i < NUMBER_OF_LEAVES; i++) {          container.appendChild(createALeaf());      }  }  function randomInteger(low, high){      return low + Math.floor(Math.random() * (high - low));  }  function randomFloat(low, high){      return low + Math.random() * (high - low);  }  function pixelValue(value){      return value + 'px';  }  function durationValue(value){      return value + 's';  }  function createALeaf(){      var leafp = document.createElement('p');      leafp.style.top = "-100px";      leafp.style.left = pixelValue(randomInteger(0, 500));      leafp.style.webkitAnimationName = 'fade, drop';      var fadeAndDropDuration = durationValue(randomFloat(5, 11));      leafp.style.webkitAnimationDuration = fadeAndDropDuration + ', ' + fadeAndDropDuration;      var leafDelay = durationValue(randomFloat(0, 5));      leafp.style.webkitAnimationDelay = leafDelay + ', ' + leafDelay;      var image = document.createElement('img');      image.src = 'images/realLeaf' + randomInteger(1, 5) + '.png';      var spinAnimationName = (Math.random() < 0.5) ? 'clockwiseSpin' : 'counterclockwiseSpinAndFlip';      image.style.webkitAnimationName = spinAnimationName;      var spinDuration = durationValue(randomFloat(4, 8));      image.style.webkitAnimationDuration = spinDuration;      leafp.appendChild(image);      return leafp;  }  window.addEventListener('load', init, false);

PS：下面看下html5 canvas处理连续帧图片,下面的代码基于IE8以上

<!DOCTYPE html>  <html>  <head>  <meta charset="utf-8">  <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no"/>  <title>Canvas Demo</title>  <script>  var canvas = null;//初始化参数  var img = null;  var ctx = null;  var imageReady = false;  window.onload = function() {      var canvas = document.getElementById("animation_canvas");      canvas.width = canvas.parentNode.clientWidth;      canvas.height = canvas.parentNode.clientHeight;      if (!canvas.getContext) {          console.log("Canvas not supported. Please install a HTML5 compatible browser.");          return;      }         // get 2D context of canvas and draw rectangel      ctx = canvas.getContext("2d");      ctx.fillStyle="black";      ctx.fillRect(0, 0, canvas.width, canvas.height);      console.log(canvas.height);      img = document.createElement('img');      img.src = "images/ab0.png";      img.onload = loaded();  }    //保证只有图像加载后才开始循环动画  function loaded() {      imageReady = true;      setTimeout( update, 1000/3);//添加3帧每秒间隔计时器  }  function redraw() {      ctx.fillStyle="black";      ctx.fillRect(0, 0, 460, 460);      ctx.drawImage(img, 0, 0, 232, 180);  }     //为了让图片以规定的速度动画，我们必须追踪已经经过的时间，然后根据分配给每帧的时间播放帧。基本步骤是：  //1、按每秒几帧设置动画速度(msPerFrame)。  //2、当你循环游戏时，计算一下自最后一帧以后已经经过了多少时间（delta）。  //3、如果已经经过的时间足够把动画帧播完，那么播放这一帧并设置累积delta为0。  //4、如果已经经过的时间不够，那么记住（累积）delta时间（acDelta）。  var frame = 0;  var lastUpdateTime = 0;  var acDelta = 0;  var msPerFrame = 200;  function update() {      requestAnimFrame(update);      var delta = Date.now() - lastUpdateTime;      //console.log(Date.now(),lastUpdateTime);      if (acDelta > msPerFrame){          acDelta = 0;          redraw();          img.src='images/ab'+frame+'.png';          frame++;           if(frame >= 3) frame = 0; //当绘制后且帧推进完，计时器就会重置。      }else{          acDelta += delta;      }      lastUpdateTime = Date.now();  }  //requestAnimFrame的作用基本上就是setTimeout，但浏览器知道你正在渲染帧，所以它可以优化绘制循环，以及如何与剩下的页面回流。  //在某些情况下，setTimeout比requestAnimFrame更好用，特别是对于手机。  //以下是在不同的浏览器上调用requestAnimFrame的情况也不同，标准的检测方法如下：  window.requestAnimFrame = (function(){      return window.requestAnimationFrame ||              window.webkitRequestAnimationFrame ||              window.mozRequestAnimationFrame ||              window.oRequestAnimationFrame ||              window.msRequestAnimationFrame ||              function( callback ){                  window.setTimeout(callback, 1000 / 3); //如果requestAnimFrame支持不可用，还是可以用回内置的setTimeout。              };  })();  </script>  </head>  <body style="position:absolute;margin:0;padding:0;width:100%;height:100%;">      <canvas id="animation_canvas"></canvas>  </body>  </html>

HTML5和Webkit实现树叶飘落动画

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