前端必备技能：如何使用 CSS画各种形状或图标
CSS能够生成各种形状。正方形和矩形很容易，因为它们是 web 的自然形状。添加宽度和高度，就得到了所需的精确大小的矩形。添加边框半径，你就可以把这个形状变成圆形，足够多的边框半径，你就可以把这些矩形变成圆形和椭圆形。
我们还可以使用 CSS 伪元素中的 ::before 和 ::after，这为我们提供了向原始元素添加另外两个形状的可能性。通过巧妙地使用定位、转换和许多其他技巧，我们可以只用一个 HTML 元素在 CSS 中创建许多形状。
虽然我们现在大都使用字体图标或者svg图片，似乎使用 CSS 来做图标意义不是很大，但怎么实现这些图标用到的一些技巧及思路是很值得我们的学习。
1. 正方形
.square {
width: 100px;
height: 100px;
background: red;
}
2. 长方形
.rectangle {
width: 200px;
height: 100px;
background: red;
}
3. 圆形
.circle {
width: 100px;
height: 100px;
background: red;
border-radius: 50%
}
4. 椭圆形
#oval {
width: 200px;
height: 100px;
background: red;
border-radius: 100px / 50px;
}
5. 上三角
.triangle-up {
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-bottom: 100px solid red;
}
6. 下三角
.triangle-down {
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-top: 100px solid red;
}
7. 左三角
.triangle-left {
width: 0;
height: 0;
border-top: 50px solid transparent;
border-right: 100px solid red;
border-bottom: 50px solid transparent;
}
8. 右三角
.triangle-right {
width: 0;
height: 0;
border-top: 50px solid transparent;
border-left: 100px solid red;
border-bottom: 50px solid transparent;
}
9. 左上角
.triangle-topleft {
width: 0;
height: 0;
border-top: 100px solid red;
border-right: 100px solid transparent;
}
10. 右上角
.triangle-topright {
width: 0;
height: 0;
border-top: 100px solid red;
border-left: 100px solid transparent;
}
11. 左下角
.triangle-bottomleft {
width: 0;
height: 0;
border-bottom: 100px solid red;
border-right: 100px solid transparent;
}
12. 右下角
.triangle-bottomright {
width: 0;
height: 0;
border-bottom: 100px solid red;
border-left: 100px solid transparent;
}
13. 箭头
.curvedarrow {
position: relative;
width: 0;
height: 0;
border-top: 9px solid transparent;
border-right: 9px solid red;
transform: rotate(10deg);
}
.curvedarrow:after {
content: "";
position: absolute;
border: 0 solid transparent;
border-top: 3px solid red;
border-radius: 20px 0 0 0;
top: -12px;
left: -9px;
width: 12px;
height: 12px;
transform: rotate(45deg);
}
14. 梯形
.trapezoid {
border-bottom: 100px solid red;
border-left: 25px solid transparent;
border-right: 25px solid transparent;
height: 0; width: 100px;
}
15. 平行四边形
.parallelogram {
width: 150px;
height: 100px;
transform: skew(20deg);
background: red;
}
16. 星星 (6角)
.star-six {
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-bottom: 100px solid red;
position: relative;
}
.star-six:after {
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-top: 100px solid red;
position: absolute;
content: "";
top: 30px;
left: -50px;
}
17. 星星 (5角)
.star-five {
margin: 50px 0;
position: relative;
display: block;
color: red;
width: 0px;
height: 0px;
border-right: 100px solid transparent;
border-bottom: 70px solid red;
border-left: 100px solid transparent;
transform: rotate(35deg);
}
.star-five:before {
border-bottom: 80px solid red;
border-left: 30px solid transparent;
border-right: 30px solid transparent;
position: absolute;
height: 0;
width: 0;
top: -45px;
left: -65px;
display: block;
content: '';
transform: rotate(-35deg);
}
.star-five:after {
position: absolute;
display: block;
color: red;
top: 3px;
left: -105px;
width: 0px;
height: 0px;
border-right: 100px solid transparent;
border-bottom: 70px solid red;
border-left: 100px solid transparent;
transform: rotate(-70deg);
content: '';
}
18. 五边形
.pentagon {
position: relative;
width: 54px;
box-sizing: content-box;
border-width: 50px 18px 0;
border-style: solid;
border-color: red transparent;
}
.pentagon:before {
content: "";
position: absolute;
height: 0;
width: 0;
top: -85px;
left: -18px;
border-width: 0 45px 35px;
border-style: solid;
border-color: transparent transparent red;
}
19. 六边形
.hexagon {
width: 100px; height: 55px;
background: red;
position: relative;
}
.hexagon:before {
content: "";
position: absolute;
top: -25px;
left: 0;
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-bottom: 25px solid red;
}
.hexagon:after {
content: "";
position: absolute;
bottom: -25px; left: 0;
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-top: 25px solid red;
}
20. 八边形
.octagon {
width: 100px;
height: 100px;
background: red;
position: relative;
}
.octagon:before {
content: "";
width: 100px;
height: 0;
position: absolute;
top: 0;
left: 0;
border-bottom: 29px solid red;
border-left: 29px solid #eee;
border-right: 29px solid #eee;
}
.octagon:after {
content: "";
width: 100px;
height: 0;
position: absolute;
bottom: 0;
left: 0;
border-top: 29px solid red;
border-left: 29px solid #eee;
border-right: 29px solid #eee;
}
21. 爱心
.heart {
position: relative;
width: 100px;
height: 90px;
}
.heart:before,.heart:after {
position: absolute;
content: "";
left: 50px;
top: 0;
width: 50px;
height: 80px;
background: red;
border-radius: 50px 50px 0 0;
transform: rotate(-45deg);
transform-origin: 0 100%;
}
.heart:after {
left: 0;
transform: rotate(45deg);
transform-origin: 100% 100%;
}
22. 无穷大
.infinity {
position: relative;
width: 212px;
height: 100px;
box-sizing: content-box;
}
.infinity:before,.infinity:after {
content: "";
box-sizing: content-box;
position: absolute;
top: 0;
left: 0;
width: 60px;
height: 60px;
border: 20px solid red;
border-radius: 50px 50px 0 50px;
transform: rotate(-45deg);
}
.infinity:after {
left: auto;
right: 0;
border-radius: 50px 50px 50px 0;
transform: rotate(45deg);
}
23. 菱形
.diamond {
width: 0;
height: 0;
border: 50px solid transparent;
border-bottom-color: red;
position: relative; top: -50px;
}
.diamond:after {
content: '';
position: absolute;
left: -50px;
top: 50px;
width: 0;
height: 0;
border: 50px solid transparent;
border-top-color: red;
}
24. 钻石
.diamond-shield {
width: 0;
height: 0;
border: 50px solid transparent;
border-bottom: 20px solid red;
position: relative;
top: -50px;
}
.diamond-shield:after {
content: '';
position: absolute;
left: -50px;
top: 20px;
width: 0;
height: 0;
border: 50px solid transparent;
border-top: 70px solid red;
}
25. 钻戒
.diamond-narrow {
width: 0;
height: 0;
border: 50px solid transparent;
border-bottom: 70px solid red;
position: relative; top: -50px;
}
.diamond-narrow:after {
content: '';
position: absolute;
left: -50px;
top: 70px;
width: 0;
height: 0;
border: 50px solid transparent;
border-top: 70px solid red;
}
26. 钻石2
.cut-diamond {
border-style: solid;
border-color: transparent transparent red transparent;
border-width: 0 25px 25px 25px;
height: 0;
width: 50px;
box-sizing: content-box;
position: relative;
margin: 20px 0 50px 0;
}
.cut-diamond:after {
content: "";
position: absolute;
top: 25px;
left: -25px;
width: 0;
height: 0;
border-style: solid;
border-color: red transparent transparent transparent;
border-width: 70px 50px 0 50px;
}
27. 蛋蛋
.egg {
display: block;
width: 126px;
height: 180px;
background-color: red;
border-radius: 50% 50% 50% 50% / 60% 60% 40% 40%;
}
28. 吃豆人
.pacman {
width: 0px;
height: 0px;
border-right: 60px solid transparent;
border-top: 60px solid red;
border-left: 60px solid red;
border-bottom: 60px solid red;
border-top-left-radius: 60px;
border-top-right-radius: 60px;
border-bottom-left-radius: 60px;
border-bottom-right-radius: 60px;
}
29. 对话泡泡
.talkbubble {
width: 120px;
height: 80px;
background: red;
position: relative;
-moz-border-radius: 10px;
-webkit-border-radius: 10px;
border-radius: 10px;
}
.talkbubble:before {
content: "";
position: absolute;
right: 100%;
top: 26px;
width: 0;
height: 0;
border-top: 13px solid transparent;
border-right: 26px solid red;
border-bottom: 13px solid transparent;
}
30. 12点 爆发
.burst-12 {
background: red;
width: 80px;
height: 80px;
position: relative;
text-align: center;
}
.burst-12:before,.burst-12:after {
content: "";
position: absolute;
top: 0;
left: 0;
height: 80px;
width: 80px;
background: red;
}
.burst-12:before {
transform: rotate(30deg);
}
#burst-12:after {
transform: rotate(60deg);
}
31. 8点 爆发
.burst-8 {
background: red;
width: 80px;
height: 80px;
position: relative;
text-align: center;
transform: rotate(20deg);
}
.burst-8:before {
content: "";
position: absolute;
top: 0;
left: 0;
height: 80px;
width: 80px;
background: red;
transform: rotate(135deg);
}
32. 太极
.yin-yang {
width: 96px;
box-sizing: content-box;
height: 48px;
background: #eee;
border-color: red;
border-style: solid;
border-width: 2px 2px 50px 2px;
border-radius: 100%;
position: relative;
}
.yin-yang:before {
content: "";
position: absolute;
top: 50%;
left: 0;
background: #eee;
border: 18px solid red;
border-radius: 100%;
width: 12px;
height: 12px;
box-sizing: content-box;
}
.yin-yang:after {
content: "";
position: absolute;
top: 50%;
left: 50%;
background: red;
border: 18px solid #eee;
border-radius: 100%;
width: 12px;
height: 12px;
box-sizing: content-box;
}
33. 徽章丝带
.badge-ribbon {
position:
relative;
background:
red; height:
100px;
width: 100px;
border-radius: 50px;
}
.badge-ribbon:before,.badge-ribbon:after {
content: '';
position: absolute;
border-bottom: 70px solid red;
border-left: 40px solid transparent;
border-right: 40px solid transparent;
top: 70px; left: -10px;
transform: rotate(-140deg);
}
.badge-ribbon:after {
left: auto; right: -10px;
transform: rotate(140deg);
}
34. 太空入侵者（电脑游戏名）
.space-invader {
box-shadow: 0 0 0 1em red, 0 1em 0 1em red, -2.5em 1.5em 0 .5em red, 2.5em 1.5em 0 .5em red, -3em -3em 0 0 red, 3em -3em 0 0 red, -2em -2em 0 0 red, 2em -2em 0 0 red, -3em -1em 0 0 red, -2em -1em 0 0 red, 2em -1em 0 0 red, 3em -1em 0 0 red, -4em 0 0 0 red, -3em 0 0 0 red, 3em 0 0 0 red, 4em 0 0 0 red, -5em 1em 0 0 red, -4em 1em 0 0 red, 4em 1em 0 0 red, 5em 1em 0 0 red, -5em 2em 0 0 red, 5em 2em 0 0 red, -5em 3em 0 0 red, -3em 3em 0 0 red, 3em 3em 0 0 red, 5em 3em 0 0 red, -2em 4em 0 0 red, -1em 4em 0 0 red, 1em 4em 0 0 red, 2em 4em 0 0 red;
background: red;
width: 1em; height: 1em;
overflow: hidden; margin: 50px 0 70px 65px;
}
35. 电视
.tv {
position: relative;
width: 200px;
height: 150px;
margin: 20px 0;
background: red;
border-radius: 50% / 10%;
color: white;
text-align: center;
text-indent: .1em;
}
.tv:before {
content: '';
position: absolute;
top: 10%;
bottom: 10%;
right: -5%;
left: -5%;
background: inherit;
border-radius: 5% / 50%;
}
36. 雪佛龙
.chevron {
position: relative;
text-align: center;
padding: 12px;
margin-bottom: 6px;
height: 60px;
width: 200px;
}
.chevron:before {
content: '';
position: absolute;
top: 0;
left: 0;
height: 100%;
width: 51%;
background: red;
transform: skew(0deg, 6deg);
}
.chevron:after {
content: '';
position:
absolute;
top: 0;
right: 0;
height: 100%;
width: 50%;
background: red;
transform: skew(0deg, -6deg);
}
37. 放大镜
.magnifying-glass {
font-size: 10em;
display: inline-block;
width: 0.4em;
box-sizing: content-box;
height: 0.4em;
border: 0.1em solid red;
position: relative;
border-radius: 0.35em;
}
.magnifying-glass:before {
content: "";
display: inline-block;
position: absolute;
right: -0.25em;
bottom: -0.1em;
border-width: 0;
background: red;
width: 0.35em;
height: 0.08em;
transform: rotate(45deg);
}
38. Facebook图标
.facebook-icon {
background: red;
text-indent: -999em;
width: 100px;
height: 110px;
box-sizing: content-box;
border-radius: 5px;
position: relative;
overflow: hidden;
border: 15px solid red;
border-bottom: 0;
}
.facebook-icon:before {
content: "/20";
position: absolute;
background: red;
width: 40px;
height: 90px;
bottom: -30px;
right: -37px;
border: 20px solid #eee;
border-radius: 25px;
box-sizing: content-box;
}
.facebook-icon:after {
content: "/20";
position: absolute;
width: 55px;
top: 50px;
height: 20px;
background: #eee;
right: 5px;
box-sizing: content-box;
}
39. 月亮
.moon {
width: 80px;
height: 80px;
border-radius: 50%;
box-shadow: 15px 15px 0 0 red;
}
40. 旗
.flag {
width: 110px;
height: 56px;
box-sizing: content-box;
padding-top: 15px;
position: relative;
background: red;
color: white;
font-size: 11px;
letter-spacing: 0.2em;
text-align: center;
text-transform: uppercase;
}
.flag:after {
content: "";
position: absolute;
left: 0;
bottom: 0;
width: 0;
height: 0;
border-bottom: 13px solid #eee;
border-left: 55px solid transparent;
border-right: 55px solid transparent;
}
41. 圆锥
.cone {
width: 0;
height: 0;
border-left: 70px solid transparent;
border-right: 70px solid transparent;
border-top: 100px solid red;
border-radius: 50%;
}
42. 十字架
.cross {
background: red;
height: 100px;
position: relative;
width: 20px;
}
.cross:after {
background: red;
content: "";
height: 20px;
left: -40px;
position: absolute;
top: 40px;
width: 100px;
}
43. 根基
.base {
background: red;
display: inline-block;
height: 55px;
margin-left: 20px;
margin-top: 55px;
position: relative; width: 100px;
}
.base:before {
border-bottom: 35px solid red;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
content: "";
height: 0;
left: 0;
position: absolute;
top: -35px;
width: 0;
}
44. 指示器
.pointer {
width: 200px;
height: 40px;
position: relative;
background: red;
}
.pointer:after {
content: "";
position: absolute;
left: 0;
bottom: 0;
width: 0;
height: 0;
border-left: 20px solid white;
border-top: 20px solid transparent;
border-bottom: 20px solid transparent;
}
.pointer:before {
content: "";
position: absolute;
right: -20px;
bottom: 0;
width: 0;
height: 0;
border-left: 20px solid red;
border-top: 20px solid transparent;
border-bottom: 20px solid transparent;
}
45. 锁
.lock {
font-size: 8px;
position: relative;
width: 18em;
height: 13em;
border-radius: 2em;
top: 10em;
box-sizing: border-box;
border: 3.5em solid red;
border-right-width: 7.5em;
border-left-width: 7.5em;
margin: 0 0 6rem 0;
}
.lock:before {
content: "";
box-sizing: border-box;
position: absolute;
border: 2.5em solid red;
width: 14em;
height: 12em;
left: 50%;
margin-left: -7em;
top: -12em;
border-top-left-radius: 7em;
border-top-right-radius: 7em;
}
.lock:after {
content: "";
box-sizing: border-box;
position: absolute;
border: 1em solid red;
width: 5em;
height: 8em;
border-radius: 2.5em;
left: 50%;
top: -1em;
margin-left: -2.5em;
}
现在用css写图形的地方确实不多了，基本都是一个图片搞定；自己留着练习感觉还是不错的，指不定什么时候会需要，留着备用也可以；最近写的项目中就遇见了一些小图标，我就是用css绘制的图形感觉效果还是不错了 ；