基于HTML5+Webkit实现树叶飘落动画
程序员文章站
2023-11-20 16:42:40
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... 17-12-28...
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>
<div id="container">
<div id="leafcontainer"></div>
<div id="message">
<em>这是基于webkit的落叶动画</em>
</div>
</div>
</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 > div {
position: absolute;
width: 100px;
height: 100px;
-webkit-animation-iteration-count: infinite;
-webkit-animation-direction: normal;
-webkit-animation-timing-function: linear;
}
#leafcontainer > div > 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 leafdiv = document.createelement('div');
leafdiv.style.top = "-100px";
leafdiv.style.left = pixelvalue(randominteger(0, 500));
leafdiv.style.webkitanimationname = 'fade, drop';
var fadeanddropduration = durationvalue(randomfloat(5, 11));
leafdiv.style.webkitanimationduration = fadeanddropduration + ', ' + fadeanddropduration;
var leafdelay = durationvalue(randomfloat(0, 5));
leafdiv.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;
leafdiv.appendchild(image);
return leafdiv;
}
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>
总结
以上所述是小编给大家介绍的基于html5+webkit实现树叶飘落动画，希望对大家有所帮助