纯CSS画的基本图形（矩形、圆形、三角形、多边形、爱心、八卦等）

这些代码的来源是css-tricks。原文链接： http://www.itivy.com/ivy/archive/2012/1/16/css-shape.html

1、圆形

CSS代码如下：宽高一样，border-radius设为宽高的一半

#circle {
width: 100px;
height: 100px;
background: red;
-moz-border-radius: 50px;
-webkit-border-radius: 50px;
border-radius: 50px;
}

2、椭圆

CSS代码如下：border-radius:水平半径/垂直半径

#oval {
width: 200px;
height: 100px;
background: red;
-moz-border-radius: 100px / 50px;
-webkit-border-radius: 100px / 50px;
border-radius: 100px / 50px;
}

3、等边三角

上三角CSS代码如下：设置border-bottom宽度实线颜色，左右border左右宽度为一半，实线透明。下三角、左三角、右三角可举一反三实现。

#triangle-up {
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-bottom: 100px solid red;
}

4、直角三角

左上三角CSS代码如下：border-top设置宽度实线颜色，border-right等宽实线透明。右上三角、左下三角、右下三角可举一反三实现。

#triangle-topleft {
width: 0;
height: 0;
border-top: 100px solid red;
border-right: 100px solid transparent;
}

5、平行四边形

CSS代码如下：transform: skew，倾斜角度即为四边形锐角的余角

#parallelogram {
width: 150px;
height: 100px;
margin-left:20px;
-webkit-transform: skew(20deg);
-moz-transform: skew(20deg);
-o-transform: skew(20deg);
background: red;
}

6、梯形

CSS代码如下：上底长为width的值，下底长为width+border-left+border-right之和，高为border-bottom

#trapezoid {
border-bottom: 100px solid red;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
height: 0;
width: 100px;
}

7、五边形（五角大楼）

CSS代码如下：

#pentagon {
position: relative;
width: 54px;
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;
}

8、六边形

CSS代码如下：

#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;
}

9、八边形

CSS代码如下：

#octagon {
width: 100px;
height: 100px;
background: red;
position: relative;
}

#octagon:before {
content: "";
position: absolute;
top: 0;
left: 0;
border-bottom: 29px solid red;
border-left: 29px solid #eee;
border-right: 29px solid #eee;
width: 42px;
height: 0;
}

#octagon:after {
content: "";
position: absolute;
bottom: 0;
left: 0;
border-top: 29px solid red;
border-left: 29px solid #eee;
border-right: 29px solid #eee;
width: 42px;
height: 0;
}

10、五角星

CSS代码如下：

#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;
-moz-transform:    rotate(35deg);
-webkit-transform: rotate(35deg);
-ms-transform:     rotate(35deg);
-o-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: '';
-webkit-transform: rotate(-35deg);
-moz-transform:    rotate(-35deg);
-ms-transform:     rotate(-35deg);
-o-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;
-webkit-transform: rotate(-70deg);
-moz-transform:    rotate(-70deg);
-ms-transform:     rotate(-70deg);
-o-transform:      rotate(-70deg);
content: '';
}

11、六角星

CSS代码如下：一个上三角和一个下三角拼合而成

#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;
}

12、八角星

CSS代码如下：

#burst-8 {
background: red;
width: 80px;
height: 80px;
position: relative;
text-align: center;
-webkit-transform: rotate(20deg);
-moz-transform: rotate(20deg);
-ms-transform: rotate(20deg);
-o-transform: rotate(20eg);
transform: rotate(20deg);
}
#burst-8:before {
content: "";
position: absolute;
top: 0;
left: 0;
height: 80px;
width: 80px;
background: red;
-webkit-transform: rotate(135deg);
-moz-transform: rotate(135deg);
-ms-transform: rotate(135deg);
-o-transform: rotate(135deg);
transform: rotate(135deg);
}

13、十二角星

CSS代码如下：

#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 {
-webkit-transform: rotate(30deg);
-moz-transform: rotate(30deg);
-ms-transform: rotate(30deg);
-o-transform: rotate(30deg);
transform: rotate(30deg);
}
#burst-12:after {
-webkit-transform: rotate(60deg);
-moz-transform: rotate(60deg);
-ms-transform: rotate(60deg);
-o-transform: rotate(60deg);
transform: rotate(60deg);
}

14、爱心

CSS代码如下：

#heart {
position: relative;
width: 100px;
height: 90px;
}
#heart:before,
#heart:after {
position: absolute;
content: "";
left: 50px;
top: 0;
width: 50px;
height: 80px;
background: red;
-moz-border-radius: 50px 50px 0 0;
border-radius: 50px 50px 0 0;
-webkit-transform: rotate(-45deg);
-moz-transform: rotate(-45deg);
-ms-transform: rotate(-45deg);
-o-transform: rotate(-45deg);
transform: rotate(-45deg);
-webkit-transform-origin: 0 100%;
-moz-transform-origin: 0 100%;
-ms-transform-origin: 0 100%;
-o-transform-origin: 0 100%;
transform-origin: 0 100%;
}
#heart:after {
left: 0;
-webkit-transform: rotate(45deg);
-moz-transform: rotate(45deg);
-ms-transform: rotate(45deg);
-o-transform: rotate(45deg);
transform: rotate(45deg);
-webkit-transform-origin: 100% 100%;
-moz-transform-origin: 100% 100%;
-ms-transform-origin: 100% 100%;
-o-transform-origin: 100% 100%;
transform-origin :100% 100%;
}

15、无穷大符号

CSS代码如下：

#infinity {
position: relative;
width: 212px;
height: 100px;
}

#infinity:before,
#infinity:after {
content: "";
position: absolute;
top: 0;
left: 0;
width: 60px;
height: 60px;
border: 20px solid red;
-moz-border-radius: 50px 50px 0 50px;
border-radius: 50px 50px 0 50px;
-webkit-transform: rotate(-45deg);
-moz-transform: rotate(-45deg);
-ms-transform: rotate(-45deg);
-o-transform: rotate(-45deg);
transform: rotate(-45deg);
}

#infinity:after {
left: auto;
right: 0;
-moz-border-radius: 50px 50px 50px 0;
border-radius: 50px 50px 50px 0;
-webkit-transform: rotate(45deg);
-moz-transform: rotate(45deg);
-ms-transform: rotate(45deg);
-o-transform: rotate(45deg);
transform: rotate(45deg);
}

16、鸡蛋

CSS代码如下：

#egg {
display:block;
width: 126px;
height: 180px;
background-color: red;
-webkit-border-radius: 63px 63px 63px 63px / 108px 108px 72px 72px;
border-radius:        50%   50%  50%  50%  / 60%   60%   40%  40%;
}

17、食豆人（Pac-Man）

CSS代码如下：

#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;
}

18、提示对话框

CSS代码如下：

#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;
}

19、钻石

CSS代码如下：

#cut-diamond {
border-style: solid;
border-color: transparent transparent red transparent;
border-width: 0 25px 25px 25px;
height: 0;
width: 50px;
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;
}

20、阴阳八卦

CSS代码如下：

#yin-yang {
width: 96px;
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;
}

#yin-yang:after {
content: "";
position: absolute;
top: 50%;
left: 50%;
background: red;
border: 18px solid #eee;
border-radius:100%;
width: 12px;
height: 12px;
}