Css3 3d animation Step1---介绍如何实现css动画
转载地址:http://www.iteye.com/topic/1116417
前言：
好久没写文章了，今天看到webQQ又一次升级。我用的chrome的画面切换甚至用到了css 3d animation+3dtransform。
这是本系列的第一篇文章，用于介绍仅用css实现3d动画。也许这篇文章也许过于超前，因为大部分的浏览器器，甚至包括FF，都还没有实现3d transform。涉及到animation的部分，你可以通过webkit内核的浏览器(Chrome or Safari)或者Firefox来浏览，但是涉及到3d transform的东西请用webkit的浏览器器浏览。
Css3 @KeyFrames Rule
什么是KeyFrames？直译过来就是关键帧。你可以把他理解为flash中的关键帧。他以关键字from开始，to结束。中间的部分都为百分比。意为动画到了某个百分比时，他的状态。而帧与帧之间的补间动画浏览器会帮你自动生成。
例如：
- <style type="text/css">
- @keyframes myfirst {
- from {background: red;}
- to {background: yellow;}
- }
- @-moz-keyframes myfirst /* Firefox */ {
- from {background: red;}
- to {background: yellow;}
- }
- @-webkit-keyframes myfirst /* Safari and Chrome */ {
- from {background: red;}
- to {background: yellow;}
- }
- </style>
试着运行下面的代码，里面可能会有你没见过的属性，我们下面会讲到
大家等待了两秒后，突然从画面左上角出现一个方块，花费5秒从红色变到黄色。可能大家已经猜到了
- <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
- <html>
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
- <title>Insert title here</title>
- <style type="text/css">
- @keyframes myfirst {
- from {background: red;}
- to {background: yellow;}
- }
- @-moz-keyframes myfirst /* Firefox */ {
- from {background: red;}
- to {background: yellow;}
- }
- @-webkit-keyframes myfirst /* Safari and Chrome */ {
- from {background: red;}
- to {background: yellow;}
- }
- #sample {
- animation-name: myfirst;
- animation-duration: 5s;
- animation-timing-function: linear;
- animation-delay: 2s;
- animation-iteration-count: infinite;
- animation-direction: alternate;
- animation-play-state: running;
- /* Firefox: */
- -moz-animation-name: myfirst;
- -moz-animation-duration: 5s;
- -moz-animation-timing-function: linear;
- -moz-animation-delay: 2s;
- -moz-animation-iteration-count: infinite;
- -moz-animation-direction: alternate;
- -moz-animation-play-state: running;
- /* Safari and Chrome: */
- -webkit-animation-name: myfirst;
- -webkit-animation-duration: 5s;
- -webkit-animation-timing-function: linear;
- -webkit-animation-delay: 2s;
- -webkit-animation-iteration-count: infinite;
- -webkit-animation-direction: alternate;
- -webkit-animation-play-state: running;
- }
- </style>
- </head>
- <body>
- <div id="sample" style="width:120px; height:120px;">
- </div>
- </body>
- </html>
animation-name： 和上面的@keyframe的名字对应起来，代表当前用的是何种变换
animation-duration: 代表动画开始到结束总共耗时多少时间
animation-timing-function： 代表动画的进行是均匀的还是先快后慢还是？他有这几个枚举值：linear:线性，ease:默认值，先慢后快，到了快一半的时候再变慢，ease-in:先慢后快,ease-out:先快后慢。ease-in-out:两头慢，中间快。cubic-bezier(n,n,n,n)：自定义，n只能输入0-1之间的值。输入的值越大，移动的越慢，4个n代表了动画的4个阶段25%，50%，75%，100%。
也就是说，linear,ease等值，只是cubic-bezier在浏览器中的预设值，可以简单表示如下：
animation-delay：代表动画延迟多少时间开始，默认为0
- #linear {animation-timing-function: cubic-bezier(0,0,1,1;}
- #ease {animation-timing-function: cubic-bezier(0.25,0.1,0.25,1);}
- #ease-in {animation-timing-function: cubic-bezier(0.42,0,1,1);}
- #ease-out {animation-timing-function: cubic-bezier(0,0,0.58,1);}
- #ease-in-out {animation-timing-function: cubic-bezier(0.42,0,0.58,1);}
animation-iteration-count:代表动画执行多少次，默认为1.如果输入infinite，则代表无限次
animation-direction：默认值为normal，代表动画执行完后从头开始。如果设置为alternate，那么动画在结束后，第二遍会反着执行一遍
animation-play-state：默认值running，代表现在是执行状态。如果要让动画停止，只需要把这个值赋值为paused
好，接下来把上面的代码串联起来。
- <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
- <html>
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
- <title>Insert title here</title>
- <style type="text/css">
- @keyframes myfirst {
- from {left:0px; top:0px; background: red; }
- 50% {left:100px; top:80px;}
- 70%, 80% {transform: rotate(-360deg);left:240px; top:240px;}
- to {left:279px; top:279px; background: yellow;}
- }
- @-moz-keyframes myfirst /* Firefox */ {
- from {left:0px; top:0px; background: red; }
- 50% {left:100px; top:80px;}
- 70%, 80% {-moz-transform: rotate(-360deg);left:240px; top:240px;}
- to {left:279px; top:279px; background: yellow;}
- }
- @-webkit-keyframes myfirst /* Safari and Chrome */ {
- from {left:0px; top:0px; background: red; }
- 50% {left:100px; top:80px;}
- 70%, 80% {-webkit-transform: rotate(-360deg) scale(0.5, 0.5);left:240px; top:240px;}
- to {left:279px; top:279px; background: yellow;}
- }
- #sample {
- animation-name: myfirst;
- animation-duration: 5s;
- animation-timing-function: linear;
- animation-iteration-count: infinite;
- animation-direction: alternate;
- /* Firefox: */
- -moz-animation-name: myfirst;
- -moz-animation-duration: 5s;
- -moz-animation-timing-function: linear;
- -moz-animation-iteration-count: infinite;
- -moz-animation-direction: alternate;
- /* Safari and Chrome: */
- -webkit-animation-name: myfirst;
- -webkit-animation-duration: 5s;
- -webkit-animation-timing-function: linear;
- -webkit-animation-iteration-count: infinite;
- -webkit-animation-direction: alternate;
- }
- </style>
- </head>
- <body>
- <div style="width:400px; height:400px; border-style:dashed; border-width:1px; position:relative;">
- <div id="sample" style="width:120px; height:120px; position:absolute;"></div>
- </div>
- </body>
- </html>