用css3实现惊艳面试官的背景动画（高级附源码）

我们传统的前端更多的是用javascript实现各种复杂动画，自从有了Css3 transition和animation以来,前端开发在动画这一块有了更高的自由度和格局,对动画的开发也越来越容易。这篇文章就让我们汇总一下使用Css3实现的各种特效。这篇文章参考《css揭秘》这本书，并作出了自己的总结，希望能让大家更有收获，也强烈推荐大家看看这本书，你值得拥有。

我们将学到

• Css3

• outline

• radial-gradient

• linear-gradient

• box-shadow

---

程序员必读

Css3编码技巧

1.实现内部虚线边框

知识点：outline

核心代码

.dash-border{

width: 200px;

height: 100px;

line-height: 100px;

outline: 1px  dashed  #fff;

outline-offset: -10px;

}

2.边框内圆角的实现

知识点：box-shadow

核心代码

.radius-border{

margin-top: 20px;

width: 180px;

height: 80px;

box-shadow: 0  0  0  10px  gray;

}

3.实现条纹背景与进度条

知识点：linear-gradient,repeating-linear-gradient

核心代码

/* 上 */

background: linear-gradient(to right,#fb3 50%,#58a 0);

background-size: 40px 100%;

box-shadow: inset 0 0 3px #555;

  

/* 中 */

background: linear-gradient(45deg,#fb3 25%,#58a 0,#58a 50%,#fb3 0,#fb3 75%,#58a 0);

background-size: 40px 40px;

  

/* 下 (可以实现任意角度的渐变，45°时显示效果最好) */

background: repeating-linear-gradient(60deg,#fb3,#fb3 15px,#58a 0,#58a 30px);

4.复杂的背景图案

知识点：linear-gradient,repeating-linear-gradient,radial-gradient

由于第二个图会有复杂的随机动画，建议大家可以亲自尝试看看效果，核心代码

<style>

.bg-grid{

margin-top: 20px;

width: 200px;

height: 200px;

background-image: linear-gradient(rgba(255,255,255,1) 2px,transparent  0),

linear-gradient(to right,rgba(255,255,255,1) 2px,transparent  0),

linear-gradient(rgba(255,255,255,.2) 1px,transparent  0),

linear-gradient(to right,rgba(255,255,255,.2) 1px,transparent  0);

background-position: -50px  -50px;

background-size: 100px  100px,100px  100px, 100%  10px, 10px  100%;

}

.animate-grid{

animation: move-grid 6s  linear  infinite;

}

@keyframes  move-grid{

0%{

background-position: -50px  -50px;

}

30%{

background-position: -100px  -100px;

}

60%{

background-position: -100px  -150px;

}

100%{

background-position: -50px  -50px;

}

}

</style>

<div  class="bg-grid black-theme"></div>

<div  class="bg-grid black-theme animate-grid"></div>

红绿灯以及红路灯随机运动动画

利用css3多背景和position实现红绿灯和背景色块移动

核心代码

<style>

.bg-dot{

margin-top: 20px;

width: 200px;

height: 50px;

background-image: radial-gradient(circle,#0cf  15px,transparent),

radial-gradient(circle,red  15px,transparent),

radial-gradient(circle,yellow  15px,transparent),

radial-gradient(circle,green  15px,transparent);

background-repeat: no-repeat;

background-position: 0  0, 50px  0, 100px  0, 150px  0, 200px  0;

background-size: 50px  50px;

}

.animate-dot{

animation: move-dot 8s  linear  infinite;

}

.animate-dot2{

animation: move-dot2 6s  linear  infinite;

}

@keyframes  move-dot{

0%{

background-position: 0  0, 50px  0, 100px  0, 150px  0;

}

30%{

background-position: 50px  0, 0  0, 100px  0, 150px  0;

}

60%{

background-position: 50px  0, 100px  0, 0  0, 150px  0;

}

100%{

background-position: 50px  0, 100px  0, 150px  0, 0  0;

}

}

@keyframes  move-dot2{

0%{

background-image: radial-gradient(circle,#0cf  15px,transparent),

radial-gradient(circle,gray  15px,transparent),

radial-gradient(circle,gray  15px,transparent),

radial-gradient(circle,gray  15px,transparent);

}

30%{

background-image: radial-gradient(circle,gray  15px,transparent),

radial-gradient(circle,red  15px,transparent),

radial-gradient(circle,gray  15px,transparent),

radial-gradient(circle,gray  15px,transparent);

}

60%{

background-image: radial-gradient(circle,gray  15px,transparent),

radial-gradient(circle,gray  15px,transparent),

radial-gradient(circle,yellow  15px,transparent),

radial-gradient(circle,gray  15px,transparent);

}

100%{

background-image: radial-gradient(circle,gray  15px,transparent),

radial-gradient(circle,gray  15px,transparent),

radial-gradient(circle,gray  15px,transparent),

radial-gradient(circle,green  15px,transparent);

}

}

</style>

<div  class="bg-dot black-theme animate-dot"></div>

<div  class="bg-dot black-theme animate-dot2"></div>

棋盘背景以及棋盘背景随机动画

利用背景渐变实现棋盘图案

核心代码

<style>

.bg-qi{

margin-top: 20px;

width: 200px;

height: 200px;

background-color: #eee;

background-image: linear-gradient(45deg,rgba(0,0,0,.25) 25%,transparent  0,transparent  75%,rgba(0,0,0,.25) 0),

linear-gradient(45deg,rgba(0,0,0,.25) 25%,transparent  0,transparent  75%,rgba(0,0,0,.25) 0);

background-position: 0  0, 20px  20px;

background-size: 40px  40px;

box-shadow: 2px  2px  4px  rgba(0,0,0,.4);

}

  

</style>

<div  class="bg-qi black-theme"></div>

伪随机背景

利用背景渐变，keyframe动画，实现复杂的伪随机动画

核心代码

<style>

.bg-line-rand{

margin-top: 20px;

width: 480px;

height: 60px;

background-color: #eee;

background-image: linear-gradient(90deg,#fb3  11px, transparent  0),

linear-gradient(90deg,#ab4  23px, transparent  0),

linear-gradient(90deg,#655  41px, transparent  0);

background-size: 41px  100%, 61px  100%, 83px  100%;

box-shadow: 2px  2px  4px  rgba(0,0,0,.4);

}

.bg-dot-rand{

margin-top: 20px;

width: 200px;

height: 200px;

background-color: #eee;

background-image: radial-gradient(circle,#fb3  5px, transparent  0),

radial-gradient(circle,#ab4  13px, transparent  0),

radial-gradient(circle,#655  31px, transparent  0);

background-repeat: no-repeat;

background-size: 101px  203px, 147px  60px, 373px  201px;

box-shadow: 2px  2px  4px  rgba(0,0,0,.4);

}

.animate1{

animation: move  4s  linear  infinite;

}

.animate2{

animation: move2 4s  linear  infinite;

}

@keyframes  move{

0%{

background-position: 0  0, 0  0, 0  0;

}

50%{

background-position: -10px  0, 20px  0, 30px  0;

}

100%{

background-position: 0  0, 30px  0, 10px  0;

}

}

@keyframes  move2{

0%{

background-position: 0  0, 0  0, 0  0;

}

50%{

background-position: -10px  30px, 20px  0, -40px  80px;

}

100%{

background-position: 0  20px, 60px  -20px, 10px  30px;

}

}

</style>

<div  class="bg-line-rand black-theme"></div>

<div  class="bg-line-rand black-theme animate1"></div>

<div  class="bg-dot-rand black-theme animate2"></div>

5.折角效果

知识点：linear-gradient

核心代码

<style>

.fold{

margin-left: auto;

margin-right: auto;

margin-bottom: 20px;

width: 200px;

height: 80px;

color: #fff;

line-height: 80px;

text-align: center;

background: linear-gradient(to left  bottom,transparent  50%,rgba(0,0,0,.5) 0) no-repeat  100%  0 / 2em  2em,

linear-gradient(-135deg,transparent  1.4em,#06c  0);

}

.linear{

background: linear-gradient(to left  bottom,transparent  50%,rgba(0,0,0,.5)) no-repeat  100%  0 / 2em  2em,

linear-gradient(-135deg,transparent  1.4em,#06c);

}

</style>

<div  class="fold">折角效果哦</div>

<div  class="fold linear">折角效果哦</div>

  

2.内阴影圆折角效果

核心代码

<style>

.fold-1{

margin-left: auto;

margin-right: auto;

margin-bottom: 20px;

position: relative;

width: 200px;

height: 80px;

border-radius: .5em;

color: #fff;

line-height: 80px;

text-align: center;

background: linear-gradient(-150deg,transparent  1.5em, #58a  0);

}

.fold-1::before{

content: "";

position: absolute;

top: 0;

right: 0;

background: linear-gradient(to left  bottom,transparent  50%,rgba(0,0,0,.2) 0,rgba(0,0,0,.4)) 100%  0  no-repeat;

width: 1.73em;

height: 3em;

transform: translateY(-1.3em) rotate(-30deg);

transform-origin: bottom  right;

border-bottom-left-radius: inherit;

box-shadow: -.2em  .2em  .3em  -.1em  rgba(0,0,0,.15);

}

  

</style>

<div  class="fold-1">折角效果哦</div>

6.自适应文本的条纹背景

知识点：linear-gradient,line-height,background-origin

核心代码

<style>

.stripe-bg{

padding: .5em;

line-height: 1.5em;

background: beige;

background-size: auto  3em;

background-origin: content-box;

background-image: linear-gradient(rgba(0,0,0,.2) 50%, transparent  0);

}

.stripe-bg > p{

margin: 0;

}

</style>

<div  class="stripe-bg">

<p>hello you</p>

<p>hello you</p>

<p>hello you</p>

<p>hello you</p>

<p>hello you</p>

</div>

7.自定义的下划线实现

知识点linear-gridient

小伙伴们注意到了吗？默认的下划线会将文字穿过，而上面的不会呦！

核心代码

<style>

.my-line{

line-height: 1.4em;

background: linear-gradient(gray,gray) no-repeat;

background-size: 100%  1px;

background-position: 0  1.15em;

text-shadow: .05em  0  #fff, -.05em  0  #fff;

}

</style>

<div  class=""><span  class="my-line">i have your big apple.you have a too? hi hi hi.</span></div>

最后

笔者3天后将推出开源的CMS系统，技术架构：

• 后台Node+Koa+redis+JsonSchema

• 管理后台界面 vue-cli3 + vue + ts + vuex + antd-vue + axios

• 客户端前台 react + antd + react-hooks + axios

后面将推出该系统的设计思想，架构和实现过程，欢迎在《趣谈前端》里查看更详细的介绍。

欢迎大家相互学习交流，一起探索前端的边界。