源于前段时候微信小程序最初火爆公测时段，把以前用 Canvas 实现的大转盘抽奖移植成微信小程序，无奈当时小程序对 Canvas 支持不够完善，只好降低用 CSS3 实现。虽然比不上 Canvas 绘图的绚丽，但也总算完成了一个抽奖的 Demo，详见：https://github.com/givebest/wechat-turntalbe-canvas。

事后想起，CSS3 实现也并不是无有益处，比如简单、快捷、调试方便、渲染想来也是要比 Canvas 要高效的，更重要的一点是支持媒体查询，大转盘也可以做成响应式的。因此抽空整理，用纯 CSS3 实现一个大转盘抽奖 Demo 并记录下来。

如果有类似需求并不想麻烦了解细节，可移步这里——Canvas 完整的大转盘抽奖项目（可以直接拿来用）https://github.com/givebest/GB-canvas-turntable。

以下就直接贴代码了,后面有演示地址。

代码

HTML

JS

(function() {
// 奖品配置
var awards = [
{'index': 0, 'text': '耳机' , 'name': 'icono-headphone'},
{'index': 1, 'text': 'iPhone' , 'name': 'icono-iphone'},
{'index': 2, 'text': '相机' , 'name': 'icono-camera'},
{'index': 3, 'text': '咖啡杯' , 'name': 'icono-cup'},
{'index': 4, 'text': '日历', 'name': 'icono-calendar'},
{'index': 5, 'text': '键盘', 'name': 'icono-keyboard'}
],
len = awards.length,
turnNum = 1 / len; // 文字旋转 turn 值

var gbWheel = $('gbWheel'),
lineList = gbWheel.querySelector('ul.gb-wheel-line'),
itemList = gbWheel.querySelector('.gb-wheel-list'),
lineListHtml = [],
itemListHtml = [];

var transform = preTransform();

awards.forEach(function(v, i, a) {
// 分隔线
lineListHtml.push('

');

// 奖项
itemListHtml.push('

');
});

lineList.innerHTML = lineListHtml.join('');
itemList.innerHTML = itemListHtml.join('');

function $(id) {
return document.getElementById(id);
};

// 旋转
var i = 0;
$('gbLottery').onclick = function() {
i++;
gbWheel.querySelector('.gb-wheel-content').style = transform + ': rotate('+ i * 3600 +'deg)';
}

// transform兼容
function preTransform() {
var cssPrefix,
vendors = {
'': '',
Webkit: 'webkit',
Moz: '',
O: 'o',
ms: 'ms'
},
testEle = document.createElement('p'),
cssSupport = {};

// 嗅探特性
Object.keys(vendors).some(function(vendor) {
if (testEle.style[vendor + (vendor ? 'T' : 't') + 'ransform'] !== undefined) {
cssPrefix = vendor ? '-' + vendor.toLowerCase() + '-' : '';
return true;
}
});

function normalizeCss(name) {
name = name.toLowerCase();
return cssPrefix ? cssPrefix + name : name;
}

cssSupport = {
transform: normalizeCss('Transform'),
}

return cssSupport.transform;
}
}());

CSS

html {
font-size: 10px
}

.gb-wheel-container ul,
.gb-wheel-container li,
.gb-wheel-container p {
margin: 0;
padding: 0
}

.gb-wheel-container ul,
.gb-wheel-container li {
list-style: none
}

.gb-wheel-container {
margin: 0 auto;
position: relative;
width: 30rem;
height: 30rem;
border-radius: 50%;
box-shadow: 0 2px 3px #333, 0 0 2px #000;
overflow: hidden
}

.gb-wheel-content {
position: absolute;
left: 1rem;
top: 1rem;
z-index: 2;
width: 28rem;
height: 28rem;
box-sizing: border-box;
border-radius: inherit;
background-clip: padding-box;
background: -webkit-radial-gradient(rgba(100, 100, 100, 0.1) 15%, transparent 16%) 0 0, -webkit-radial-gradient(rgba(100, 100, 100, 0.1) 15%, transparent 16%) 8px 8px, -webkit-radial-gradient(rgba(255, 255, 255, 0.1) 15%, transparent 20%) 0 1px, -webkit-radial-gradient(rgba(255, 255, 255, 0.1) 15%, transparent 20%) 8px 9px;
background: radial-gradient(rgba(100, 100, 100, 0.1) 15%, transparent 16%) 0 0, radial-gradient(rgba(100, 100, 100, 0.1) 15%, transparent 16%) 8px 8px, radial-gradient(rgba(255, 255, 255, 0.1) 15%, transparent 20%) 0 1px, radial-gradient(rgba(255, 255, 255, 0.1) 15%, transparent 20%) 8px 9px;
background-color: #ffcb3f;
background-size: 12px 14px
}

.gb-wheel-content:before {
content: ' ';
position: absolute;
left: -1rem;
top: -1rem;
z-index: -1;
width: 28rem;
height: 28rem;
border-radius: inherit;
border: 1rem solid #E44025;
box-shadow: 0 0 2px 2px rgba(0, 0, 0, 0.2) inset
}

.gb-wheel-list {
position: absolute;
left: 0;
top: 0;
width: inherit;
height: inherit;
z-index: 9999
}

.gb-wheel-item {
position: absolute;
left: 0;
top: 0;
width: 100%;
height: 100%;
color: #e4370e;
font-weight: bold;
text-shadow: 0 1px 1px rgba(255, 255, 255, 0.6)
}

.gb-wheel-icontent {
position: relative;
display: block;
padding-top: 1.5rem;
margin: 0 auto;
text-align: center;
-webkit-transform-origin: 50% 14rem;
-ms-transform-origin: 50% 14rem;
transform-origin: 50% 14rem
}

.gb-wheel-itext {
font-size: 1.4rem;
font-weight: lighter
}

.gb-wheel-iicon [class*=icono-] {
color: #e4370e
}

.gb-wheel-line {
position: absolute;
left: 0;
top: 0;
width: inherit;
height: inherit;
z-index: 99
}

.gb-wheel-litem {
position: absolute;
left: 14rem;
top: 0;
width: 1px;
height: 14rem;
background-color: rgba(228, 55, 14, 0.6);
overflow: hidden;
-webkit-transform-origin: 50% 14rem;
-ms-transform-origin: 50% 14rem;
transform-origin: 50% 14rem
}

.gb-wheel-btn {
position: absolute;
left: 11rem;
top: 11rem;
z-index: 400;
width: 8rem;
height: 8rem;
border-radius: 50%;
color: #F4E9CC;
background-color: #E44025;
line-height: 8rem;
text-align: center;
font-size: 2rem;
text-shadow: 0 -1px 1px rgba(0, 0, 0, 0.6);
box-shadow: 0 3px 5px rgba(0, 0, 0, 0.6), 0 0 5px 4px rgba(0, 0, 0, 0.2) inset;
text-decoration: none
}

a.gb-wheel-btn {
border-bottom: none
}

.gb-wheel-btn::after {
position: absolute;
content: '';
left: 2.5rem;
top: -1rem;
width: 3rem;
height: 3rem;
background-color: #E44025;
-webkit-transform: rotate(45deg);
-ms-transform: rotate(45deg);
transform: rotate(45deg);
box-shadow: 0 3px 5px rgba(0, 0, 0, 0.6), 0 0 5px 4px rgba(0, 0, 0, 0.2) inset
}

.gb-wheel-btn.disabled,
.gb-wheel-btn.disabled::after {
pointer-events: none;
background: #B07A7B;
color: #ccc
}

.gb-wheel-run {
-webkit-transition: transform 6s ease;
transition: transform 6s ease
}

@media only screen and (min-width: 320px) {
html {
font-size: 10px
}
}

@media only screen and (min-width: 375px) {
html {
font-size: 11.71875px
}
}

@media only screen and (min-width: 480px) {
html {
font-size: 15px
}
}

演示

http://blog.givebest.cn/GB-css3-wheel.html

项目

https://github.com/givebest/GB-css3-wheel

感谢

奖品Icon来自：https://github.com/saeedalipoor/icono
CSS3转盘背景来自：http://lea.verou.me/css3patterns/

顺便推荐 Lea Verou(W3C CSS小组特邀专家) 的书《CSS Secrets: Better Solutions to Everyday Web Design Problems》，让你震撼，原来 CSS 还可以这样用、可以实现这么多绚丽的特效。 已有中文版《CSS揭秘》，CSS魔法译。