详解用 CSS 实现一个抽奖转盘的思路，并附详细代码

共 11442字，需浏览 23分钟

· 2021-01-05

来源 | https://www.cnblogs.com/wenruo/p/9732704.html

最终效果如下：

基本是用CSS实现的，没有用图片，加一丢丢JS。完全没有考虑兼容性。

首先画一个转盘

<html lang="en"><head>  <meta charset="UTF-8">  <title>幸运大转盘title>  <style>    /* 重置默认样式 */    * {      margin: 0;      padding: 0;      border: none;      outline: none;    }    .wrapper {      position: relative;      height: 200px;      width: 200px;      padding: 20px;      margin: 20px;      background-color: #c0381f;      box-shadow: #000000 0px 0px 10px;      border-radius: 50%;    }    .panel {      position: relative;      height: 200px;      width: 200px;      background-color: #b7b7b7;      border-radius: 100px;    }    .pointer {      position: absolute;      left: 79px;      top: 79px;      z-index: 10;      height: 30px;      width: 30px;      padding: 6px;      color: #fff899;      line-height: 15px;      font-size: 12px;      text-align: center;      background-color: #dc5b5b;      border-radius: 50%;      border: 1px solid #c0381f;    }style>head><body>  <div class="wrapper">    <div class="panel">      <div class="pointer">开始抽奖div>    div>  div>body>html>

效果如下，配色什么的不要在意，可能比较丑。。。

然后写抽奖指针的小箭头，用CSS画三角形是一个比较常见的问题，通过设置width和height为0，然后用border实现。

如图，矩形是由四个三角形边框组成的，只要设置其它边颜色为透明，就可以获得单独的三角形。

这里通过伪元素after实现三角形，并通过绝对定位将三角形定位到中间小圆的顶端。

.pointer::after {      content: '';      position: absolute;      left: 14px;      top: -24px;      border-width: 12px 6px;      border-style: solid;      border-color: transparent;      border-bottom-color: #c0381f;}

现在才像一个指针了。

哦接下来是实现转盘背景，不同的扇区对应不同的奖品，这样就有一个需求：实现任意角度扇形。

可能会想当然的认为和三角形一样，不过是加一个border-radius而已，高度是圆半径，宽度是tan(θ/2)，但是实现出来的效果和想象并不一样……（可能需要做一些其他操作以达到效果，但是我没想到。

最后还是求助了搜索引擎。不得不承认dalao们实在是太nb了，qaq……通过 linear-gradient 实现想法是真的棒。不过还有好多复杂的实现看的不是很懂= =

How to draw a circle sector in CSS?

Segments in a circle using CSS3

3种纯CSS实现中间镂空的12色彩虹渐变圆环方法

实现就是通过两个正方形取相交区域。

我觉图画的还是挺好的:D

没有用伪元素实现，因为我还要加文字，至于文字的位置，我真的是瞎调的，反正正经写代码也不会这么写= =

<html lang="en"><head>    <meta charset="UTF-8">    <title>Documenttitle>    <style>        .sector {            position: absolute;            width: 100px;            height: 200px;            margin: 100px;            border-radius: 0px 100px 100px 0;            overflow: hidden;            transform: rotate(-18deg);        }        .sector-inner {            text-align: center;            display: block;            width: 40px;            padding: 5px 3px 0 57px;            height: 195px;            background: #ffeab1;            transform: translateX(-100px) rotate(36deg);            transform-origin: right center;            border-radius: 100px 0 0 100px;        }        .sector-inner span {            display: block;            transform-origin: center;            transform: rotate(-19deg);            color: #d46854;        }style>head><body>    <div class="sector">        <div class="sector-inner">            <span>谢谢参与span>        div>    div>body>html>

效果如下，一个带有文字的小扇形~~

OK，现在写一堆扇形放到一开始的转盘上。

现在的代码是酱紫滴~~太长了折起来。

<html lang="en"><head>  <meta charset="UTF-8">  <title>幸运大转盘title>  <style>    /* 重置默认样式 */    * {      margin: 0;      padding: 0;      border: none;      outline: none;    }    .wrapper {      position: relative;      height: 200px;      width: 200px;      padding: 20px;      margin: 20px;      background-color: #c0381f;      box-shadow: #000000 0px 0px 10px;      border-radius: 50%;    }    .panel {      position: relative;      height: 200px;      width: 200px;      background-color: #b7b7b7;      border-radius: 100px;    }    .sector {      position: absolute;      width: 100px;      height: 200px;      border-radius: 0px 100px 100px 0;      overflow: hidden;      left: 100px;      top: 0px;      transform-origin: left center;    }    .sector:nth-child(1) {      transform: rotate(-18deg);    }    .sector:nth-child(2) {      transform: rotate(18deg);    }    .sector:nth-child(3) {      transform: rotate(54deg);    }    .sector:nth-child(4) {      transform: rotate(90deg);    }    .sector:nth-child(5) {      transform: rotate(126deg);    }    .sector:nth-child(6) {      transform: rotate(162deg);    }    .sector:nth-child(7) {      transform: rotate(198deg);    }    .sector:nth-child(8) {      transform: rotate(234deg);    }    .sector:nth-child(9) {      transform: rotate(270deg);    }    .sector:nth-child(10) {      transform: rotate(306deg);    }    .sector:nth-child(2n+1) .sector-inner {      background: #fef6e0;    }    .sector:nth-child(2n) .sector-inner {      background: #ffffff;    }    .sector-inner {      text-align: center;      display: block;      width: 40px;      padding: 5px 3px 0 57px;      height: 195px;      transform: translateX(-100px) rotate(36deg);      transform-origin: right center;      border-radius: 100px 0 0 100px;    }    .sector-inner span {      display: block;      transform-origin: center;      transform: rotate(-19deg);      color: #d46854;    }    .pointer {      position: absolute;      left: 79px;      top: 79px;      z-index: 10;      height: 30px;      width: 30px;      padding: 6px;      color: #fff899;      line-height: 15px;      font-size: 12px;      text-align: center;      background-color: #dc5b5b;      border-radius: 50%;      border: 1px solid #c0381f;    }    .pointer::after {      content: '';      position: absolute;      left: 14px;      top: -24px;      border-width: 12px 6px;      border-style: solid;      border-color: transparent;      border-bottom-color: #c0381f;    }style>head><body>  <div class="wrapper">    <div class="panel">      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span> 50 积分span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>100话费span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span> 50 积分span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>100话费span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span> 50 积分span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>10元话费span>        div>      div>      <div class="pointer">开始抽奖div>    div>  div>body>html>

嘻嘻，现在是抽奖转盘的样子了吧~~~

最后再加点浮夸的灯。

<html lang="en"><head>  <meta charset="UTF-8">  <title>幸运大转盘title>  <style>    /* 重置默认样式 */    * {      margin: 0;      padding: 0;      border: none;      outline: none;    }    .wrapper {      position: relative;      height: 200px;      width: 200px;      padding: 20px;      margin: 20px;      background-color: #c0381f;      box-shadow: #000000 0px 0px 10px;      border-radius: 50%;    }    .light {      position: absolute;      height: 10px;      width: 10px;      border-radius: 50%;      top: 5px;      left: 115px;      transform-origin: 5px 115px;    }    .light:nth-child(2n) {      background-color: #fafce7;    }    .light:nth-child(2n+1) {      background-color: #ffe58b;    }    .light:nth-child(2) {      transform: rotate(36deg);    }    .light:nth-child(3) {      transform: rotate(72deg);    }    .light:nth-child(4) {      transform: rotate(108deg);    }    .light:nth-child(5) {      transform: rotate(144deg);    }    .light:nth-child(6) {      transform: rotate(180deg);    }    .light:nth-child(7) {      transform: rotate(216deg);    }    .light:nth-child(8) {      transform: rotate(252deg);    }    .light:nth-child(9) {      transform: rotate(288deg);    }    .light:nth-child(10) {      transform: rotate(324deg);    }    .panel {      position: relative;      height: 200px;      width: 200px;      background-color: #b7b7b7;      border-radius: 100px;    }    .sector {      position: absolute;      width: 100px;      height: 200px;      border-radius: 0px 100px 100px 0;      overflow: hidden;      left: 100px;      top: 0px;      transform-origin: left center;    }    .sector:nth-child(1) {      transform: rotate(-18deg);    }    .sector:nth-child(2) {      transform: rotate(18deg);    }    .sector:nth-child(3) {      transform: rotate(54deg);    }    .sector:nth-child(4) {      transform: rotate(90deg);    }    .sector:nth-child(5) {      transform: rotate(126deg);    }    .sector:nth-child(6) {      transform: rotate(162deg);    }    .sector:nth-child(7) {      transform: rotate(198deg);    }    .sector:nth-child(8) {      transform: rotate(234deg);    }    .sector:nth-child(9) {      transform: rotate(270deg);    }    .sector:nth-child(10) {      transform: rotate(306deg);    }    .sector:nth-child(2n+1) .sector-inner {      background: #fef6e0;    }    .sector:nth-child(2n) .sector-inner {      background: #ffffff;    }    .sector-inner {      text-align: center;      display: block;      width: 40px;      padding: 5px 3px 0 57px;      height: 195px;      transform: translateX(-100px) rotate(36deg);      transform-origin: right center;      border-radius: 100px 0 0 100px;    }    .sector-inner span {      display: block;      transform-origin: center;      transform: rotate(-19deg);      color: #d46854;    }    .pointer {      position: absolute;      left: 79px;      top: 79px;      z-index: 10;      height: 30px;      width: 30px;      padding: 6px;      color: #fff899;      line-height: 15px;      font-size: 12px;      text-align: center;      background-color: #dc5b5b;      border-radius: 50%;      border: 1px solid #c0381f;    }    .pointer::after {      content: '';      position: absolute;      left: 14px;      top: -24px;      border-width: 12px 6px;      border-style: solid;      border-color: transparent;      border-bottom-color: #c0381f;    }style>head><body>  <div class="wrapper">    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="panel">      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span> 50 积分span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>100话费span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span> 50 积分span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>100话费span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span> 50 积分span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>10元话费span>        div>      div>      <div class="pointer">开始抽奖div>    div>  div>body>html>

现在转盘CSS部分基本完成。简单写一下JS部分。点击中间的指针时，指针会转，可以拉一条贝塞尔曲线，控制动画的速度。

贝塞尔曲线可以简单的看作是时间-距离曲线，斜率就是速度。因为转盘的速度肯定是先快后慢，随便拉一条。

http://cubic-bezier.com/#.2,.93,.43,1

CSS中添加属性

.pointer {  // ...  transition: transform 3s cubic-bezier(.2,.93,.43,1);}

点击开始抽奖的时候，为中间的指针加一个旋转的角度。这里有一个问题就是不同的扇区抽到的概率是相同的，改成不同应该…也蛮简单的，不过主要是想练下CSS，JS就随便写了。

JS部分代码。。

let getEle = document.getElementsByClassName.bind(document);let pointer = getEle('pointer')[0];let result = getEle('result')[0];
let onRotation = false; // 记录当前是否正在旋转，如果正在旋转，就不能继续点击了let reward = ['谢谢参与', '50积分', '谢谢参与', '100元话费', '50积分', '谢谢参与', '100元话费', '谢谢参与', '50积分', '10元话费'];
// 根据随机角度获取奖励let getReward = (function() {  currentDeg = 0;  return function() {    // 转三圈到四圈    let rotateDeg = Math.random() * 360 + 1080;    currentDeg += rotateDeg;    let rewardText = reward[Math.floor((currentDeg + 18) % 360 / 36)]    return {      deg: currentDeg,      text: rewardText === '谢谢参与' ? '很遗憾，您没有获得奖品。' : '恭喜获得: ' + rewardText    }  }})();
pointer.addEventListener('click', () => {  if (onRotation) return;  console.log('开始抽奖');  onRotation = true;  let nextStatus = getReward();  console.log(nextStatus)  result.innerText = nextStatus.text;  result.style.display = 'none';  pointer.style.transform = `rotateZ(${nextStatus.deg}deg)`;})pointer.addEventListener('transitionend', () => {  console.log('抽奖结束');  onRotation = false;  result.style.display = 'block';})

现在一个抽奖转盘基本完成了，最后一个需求，如果旁边的等能够亮起来就好了。

至于灯怎么亮，就需要用到CSS3的动画了，我还不太熟悉，先去学习一下>_<

我学完回来了，参考教程http://www.ruanyifeng.com/blog/2014/02/css_transition_and_animation.html，内容不是很多。

animation-name 指定动画名称，

animation-duration 指定动画持续时间，

animation-timing-function 指定动画函数，和transition的函数是一样的，

animation-delay 指定动画延迟多久后执行，

animation-iteration-count 指定动画执行多少次，默认为一次，可以指定为infinite，无限循环。

animation-direction 指定动画多次播放时，一次结束，下一次怎么接上一次，如图。

animation-fill-mode 指定动画结束后停在什么位置，默认回到起始状态，forwards表示让动画停留在结束状态，backwards让动画回到第一帧的状态，both根据animation-direction轮流应用forwards和backwards规则。

animation-play-state 动画执行状态，默认为running，可以设置为pause，动画将在当前状态停止，再改为running时，会接着上一次停止的位置继续执行动画。

使用关键字 keyframes 来定义一个动画。通过百分比指定其中任意几个状态。

尝试着写一下=。=

<html lang="en"><head>    <meta charset="UTF-8">    <title>Documenttitle>    <style>        div {            height: 30px;            width: 30px;            animation: 1s twinkling 3, 100ms 3s twinkling 3;        }        @keyframes twinkling {            50% { background: red; }        }style>head><body>    <div>div>body>html>

这是一个方块，先慢速闪三下，再快速闪三下，最后消失。

animation: 1s twinkling 3;

就相当于

animation-name: twinkling;animation-duration: 1s;animation-timing-function: ease;animation-delay: 0s;animation-iteration-count: 3;animation-direction: normal;animation-fill-mode: none;
animation-play-state: running;

效果

我觉得还可以:P 反正我只能写成这样了。

最后把动画加到转盘的灯上。完成代码（好像颜色变了，咳，那是因为我animation学了太久都掉色了）：

<html lang="en"><head>  <meta charset="UTF-8">  <title>幸运大转盘title>  <style>    * { /* 重置默认样式 */      margin: 0;      padding: 0;      border: none;      outline: none;      user-select: none;    }    .wrapper {      position: relative;      height: 200px;      width: 200px;      padding: 20px;      margin: 20px;      background-color: #ff5555;      box-shadow: #000000 0px 0px 10px;      border-radius: 50%;    }    .light {      position: absolute;      height: 10px;      width: 10px;      border-radius: 50%;      top: 5px;      left: 115px;      transform-origin: 5px 115px;    }    .light-twinkling {      animation: 1s twinkling 3, 100ms 3s twinkling 3;    }    .light:nth-child(2n) {      background-color: #fafce7;    }    .light:nth-child(2n+1) {      background-color: #ffe58b;    }    .light:nth-child(2) {      transform: rotate(36deg);    }    .light:nth-child(3) {      transform: rotate(72deg);    }    .light:nth-child(4) {      transform: rotate(108deg);    }    .light:nth-child(5) {      transform: rotate(144deg);    }    .light:nth-child(6) {      transform: rotate(180deg);    }    .light:nth-child(7) {      transform: rotate(216deg);    }    .light:nth-child(8) {      transform: rotate(252deg);    }    .light:nth-child(9) {      transform: rotate(288deg);    }    .light:nth-child(10) {      transform: rotate(324deg);    }    .panel {      position: relative;      height: 200px;      width: 200px;      background-color: #b7b7b7;      border-radius: 100px;    }    .sector {      position: absolute;      left: 100px;      top: 0px;      width: 100px;      height: 200px;      font-size: 14px;      border-radius: 0px 100px 100px 0;      overflow: hidden;      transform-origin: left center;    }    .sector:nth-child(1) {      transform: rotate(-18deg);    }    .sector:nth-child(2) {      transform: rotate(18deg);    }    .sector:nth-child(3) {      transform: rotate(54deg);    }    .sector:nth-child(4) {      transform: rotate(90deg);    }    .sector:nth-child(5) {      transform: rotate(126deg);    }    .sector:nth-child(6) {      transform: rotate(162deg);    }    .sector:nth-child(7) {      transform: rotate(198deg);    }    .sector:nth-child(8) {      transform: rotate(234deg);    }    .sector:nth-child(9) {      transform: rotate(270deg);    }    .sector:nth-child(10) {      transform: rotate(306deg);    }    .sector:nth-child(2n+1) .sector-inner {      background: #fef6e0;    }    .sector:nth-child(2n) .sector-inner {      background: #ffffff;    }    .sector-inner {      text-align: center;      display: block;      width: 40px;      padding: 5px 3px 0 57px;      height: 195px;      transform: translateX(-100px) rotate(36deg);      transform-origin: right center;      border-radius: 100px 0 0 100px;    }    .sector-inner span {      display: block;      transform-origin: center;      transform: rotate(-19deg);      color: #d46854;    }    .pointer {      position: absolute;      left: 79px;      top: 79px;      z-index: 10;      height: 30px;      width: 30px;      padding: 6px;      color: #fff899;      line-height: 15px;      font-size: 12px;      text-align: center;      background-color: #ff5350;      border-radius: 50%;      border: 1px solid #ff5350;      transition: transform 3s cubic-bezier(.2,.93,.43,1);    }    .pointer::after {      content: '';      position: absolute;      left: 14px;      top: -24px;      border-width: 12px 6px;      border-style: solid;      border-color: transparent;      border-bottom-color: #ff5350;      transform-origin: center;    }    .result {      margin: 20px 60px;    }
    @keyframes twinkling {      50% { background: transparent; }    }style>head><body>  <div class="wrapper">    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="light">div>    <div class="panel">      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span> 5 0 积分span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>100元话费span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span> 5 0 积分span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>100元话费span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>谢谢参与span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span> 5 0 积分span>        div>      div>      <div class="sector">        <div class="sector-inner">          <span>10元话费span>        div>      div>      <div class="pointer">开始抽奖div>    div>  div>  <div class="result">div>
  <script>    let getEle = document.getElementsByClassName.bind(document);    let pointer = getEle('pointer')[0];    let result = getEle('result')[0];    let lights = Array.prototype.slice.call(getEle('light'));
    let onRotation = false; // 记录当前是否正在旋转，如果正在旋转，就不能继续点击了    let reward = ['谢谢参与', '50积分', '谢谢参与', '100元话费', '50积分',     '谢谢参与', '100元话费', '谢谢参与', '50积分', '10元话费'];
    // 根据随机角度获取奖励    let getReward = (function() {      currentDeg = 0;      return function() {        // 转三圈到四圈        let rotateDeg = Math.random() * 360 + 1080;        currentDeg += rotateDeg;        let rewardText = reward[Math.floor((currentDeg + 18) % 360 / 36)]        return {          deg: currentDeg,          text: rewardText === '谢谢参与' ? '很遗憾，您没有获得奖品。' : '恭喜获得: ' + rewardText        }      }    })();
    pointer.addEventListener('click', () => {      if (onRotation) return;      console.log('开始抽奖');      onRotation = true;      lights.forEach(light => { light.className += ' light-twinkling'; });      let nextStatus = getReward();      console.log(nextStatus)      result.innerText = nextStatus.text;      result.style.display = 'none';      pointer.style.transform = `rotateZ(${nextStatus.deg}deg)`;    })    pointer.addEventListener('transitionend', () => {      console.log('抽奖结束');      setTimeout(() => { // 等闪烁三下结束        onRotation = false;        lights.forEach(light => { light.className = 'light'; });        result.style.display = 'block';      }, 300);    })script>body>html>