CSS动画实例：跳跃的字符
1．翻转的字符
在页面中放置一个类名为container的层作为容器，在该层中放置5个字符区域，HTML代码描述如下：
<div class="container">
<span>H</span>
<span>E</span>
<span>L</span>
<span>L</span>
<span>O</span>
</div>
为container和span定义CSS样式规则，并定义实现5个字符翻转的动画关键帧。完整的HTML文件内容如下。
<!DOCTYPE html> <html> <head> <title>字符翻转</title> <style> .container { margin: 0 auto; width: 500px; height: 300px; position: relative; overflow: hidden; display:flex; align-items: center; justify-content: center; border: 4px solid rgba(255, 0, 0, 0.9); background:#d8d8d8; border-radius: 10%; } .container>span { font-size: 130px; font-family: "Impact",sans-serif; display: inline-block; animation:flip 2s infinite linear; transform-origin:0 70%; transform-style:preserve-3d; } @keyframes flip { 50% { transform: rotateX(360deg); } 100% { transform: rotateX(360deg); } } .container>span:nth-child(1n+0) { color:var(--color); animation-delay: var(--delay); } </style> </head> <body> <div class="container"> <span style="--delay:0s;--color:#f00">H</span> <span style="--delay:0.4s;--color:#f0f">E</span> <span style="--delay:0.8s;--color:#ff0">L</span> <span style="--delay:1.2s;--color:#0ff">L</span> <span style="--delay:1.6s;--color:#800080">O</span> </div> </body> </html>
在浏览器中打开包含这段HTML代码的html文件，可以呈现出如图1所示的动画效果。
图1 字符绕X轴翻转
若将上面的关键帧设置中的两个属性值“rotateX”均改成“rotateY”，则呈现如图2所示的动画效果。
图2 字符绕Y轴翻转
若将上面的关键帧设置中的两个属性值“rotateX”均改成“rotateZ”，则呈现如图3所示的动画效果。
图3 字符绕Y轴翻转
2．跳跃的字符
我们可以通过修改字符区span的top属性的属性值让字符上下移动，同时设置文本的阴影，形成字符的跳跃动画效果。
编写的完整HTML文件如下。
<!DOCTYPE HTML> <html> <head> <title>跳跃的字符</title> <style> .container { margin: 0 auto; width: 600px; height: 200px; position: relative; overflow: hidden; display:flex; align-items: center; justify-content: center; border: 4px solid rgba(255, 0, 0, 0.9); background:#f5f5f5; border-radius: 10%; } .container>span { position: relative; top: 20px; display: inline-block; animation: bounce .3s ease infinite alternate; font-family: "Impact",sans-serif; font-size: 80px; text-shadow: 0 1px 0 #CCC, 0 2px 0 #CCC, 0 3px 0 #CCC, 0 4px 0 #CCC, 0 5px 0 #CCC, 0 6px 0 transparent, 0 7px 0 transparent, 0 8px 0 transparent, 0 9px 0 transparent, 0 10px 10px rgba(0, 0, 0, .4); } .container>span:nth-child(1n+0) { color:var(--color); animation-delay: var(--delay); } @keyframes bounce { 100% { top: -20px; text-shadow: 0 1px 0 #CCC, 0 2px 0 #CCC, 0 3px 0 #CCC, 0 4px 0 #CCC, 0 5px 0 #CCC, 0 6px 0 #CCC, 0 7px 0 #CCC, 0 8px 0 #CCC, 0 9px 0 #CCC, 0 50px 25px rgba(0, 0, 0, .2); } } </style> </head> <body> <div class="container"> <span style="--delay:0s;--color:#f00">H</span> <span style="--delay:0.1s;--color:#f0f">a</span> <span style="--delay:0.2s;--color:#ff0">p</span> <span style="--delay:0.3s;--color:#0f0">p</span> <span style="--delay:0.4s;--color:#0ff">y</span> <span style="--delay:0.5s;--color:#00f">N</span> <span style="--delay:0.6s;--color:#800080">e</span> <span style="--delay:0.7s;--color:#008080">w</span> <span style="--delay:0.8s;--color:#ff6347">Y</span> <span style="--delay:0.9s;--color:#ee82ee">e</span> <span style="--delay:1.0s;--color:#8b4513">a</span> <span style="--delay:1.1s;--color:#fa8072">r</span> </div> </body> </html>
在浏览器中打开包含这段HTML代码的html文件，可以呈现出如图4所示的动画效果。
图4 跳跃的字符
3．霓虹字符
通过滤镜的方式让文字发光，形成霓虹文字效果。编写HTML文件内容如下。
<!DOCTYPE html> <html> <head> <title>霓虹字符</title> <style> .container { margin: 0 auto; width: 500px; height: 300px; position: relative; overflow: hidden; display:flex; align-items: center; justify-content: center; border: 4px solid rgba(255, 0, 0, 0.9); background:#000000; border-radius: 10%; } .container>span { margin-right: 10px; display: inline-block; font-size: 100px; font-family: "Impact",sans-serif; color: white; text-shadow: 0 0 10px #fff, 0 0 20px #fff, 0 0 30px #e60073, 0 0 40px #e60073, 0 0 50px #e60073, 0 0 60px #e60073, 0 0 70px #e60073; animation-name: anim; animation-timing-function: linear; animation-direction: alternate-reverse; animation-iteration-count: infinite; } .container>span:nth-child(1) { animation-delay: 0.2s; animation-duration: 0.5s; } .container>span:nth-child(2) { animation-delay: 0.4s; animation-duration: 1s; } .container>span:nth-child(3) { animation-delay: 0.6s; animation-duration: 1.5s; } .container>span:nth-child(4) { animation-delay: 0.8s; animation-duration: 2s; } .container>span:nth-child(5) { animation-delay: 1s; animation-duration: 2.5s; } @keyframes anim { 0% { opacity: .1; background-position: 0 0; filter: hue-rotate(0deg); } 10% { background-position: 5px 0; } 20% { background-position: -5px 0; } 30% { background-position: 15px 0; } 40% { background-position: -5px 0; } 50% { background-position: -25px 0; } 60% { background-position: -50px 0; } 70% { background-position: 0 -20px; } 80% { background-position: -60px -20px;} 81% { background-position: 0 0; } 100% { opacity: 1; background-position: 0 0; filter: hue-rotate(360deg); } } </style> </head> <body> <div class="container"> <span>W</span> <span>U</span> <span>H</span> <span>A</span> <span>N</span> </div> </body> </html>
在浏览器中打开包含这段HTML代码的html文件，可以呈现出如图5所示的动画效果。
图5 霓虹文字
