Vue+CSS3实现转盘抽奖的示例代码

前端  /  管理员 发布于 2020-03-08 13:33:16   50

最近有个转盘抽奖的需求，搜了一下现有的轮子，有的是用jQuery的动画函数实现的，有的是用canvas绘图然后再用高频率的setTimeout调用旋转方法，前者太老了没法简单移植到vue项目，后者感觉性能表现可能不会太好。也有一些用CSS动画的方案，设计了加速-匀速-减速三个动画，再计算偏转角度让三个动画尽可能无缝衔接，但我感觉绕了大远路，应该有更简单轻量的实现方案。个人更倾向于用transition来实现，不过网上的例子感觉还不够好，有的倾斜文字都没有对齐，最后还是自己手写了一个。

无需jQuery，不用js脚本实现动画细节，动画效果完全连续无需衔接，支持动态设置2个以上任意数量的奖项。

核心思路是用transition以及rotate实现旋转动画，使用transition-origin和rotate绘制出定位较为精确的轮盘奖项。

代码及实例展示

<script src="//unpkg.com/vue/dist/vue.js"></script><span id="app">  <span>Prize number: {{ prizeNumber }}</span>  <button type="button" @click="!rolling && prizeNumber < 8 && (prizeNumber++)" :disabled="rolling || prizeNumber === 8">Add</button>  <button type="button" @click="!rolling && prizeNumber > 2 && (prizeNumber--)" :disabled="rolling || prizeNumber === 2">Remove</button>   <div class="wheel-wrapper">    <div      class="wheel-pointer"      @click="onClickRotate"    >      Start    </div>    <div      class="wheel-bg"      :class="{freeze: freeze}"      :style="`transform: rotate(${wheelDeg}deg)`"    >      <div class="prize-list">        <div          class="prize-item-wrapper"          v-for="(item,index) in prizeList"          :key="index"        >          <div            class="prize-item"            :style="`transform: rotate(${(360/ prizeList.length) * index}deg)`"          >            <div class="prize-name">              {{ item.name }}            </div>            <div class="prize-icon">              <img :src="item.icon">            </div>          </div>        </div>      </div>    </div>  </div></div>

html {   background: #DD7C7D;}.wheel-wrapper {    width: 300px;    height: 300px;    position: absolute;    top: 50%;    left: 50%;    transform: translate(-50%, -50%);  }  .wheel-pointer {    width: 60px;    height: 60px;    border-radius: 1000px;    background: yellow;    position: absolute;    left: 50%;    top: 50%;    transform: translate(-50%, -50%);    text-align: center;    line-height: 60px;    z-index: 10;  }  .wheel-bg {    width: 100%;    height: 100%;    border-radius: 1000px;    overflow: hidden;    transition: transform 4s ease-in-out;    background: #7EEF97;        &.freeze {      transition: none;      background: red;    }  }  .prize-list {    width: 100%;    height: 100%;    position: relative;    text-align: center;  }  .prize-item-wrapper {    position: absolute;    top: 0;    left: 50%;    transform: translateX(-50%);    width: 150px;    height: 150px;  }  .prize-item {    width: 100%;    height: 100%;    transform-origin: bottom;    .prize-name {      padding: 16px 0;    }    .prize-icon {}  }

var Main = {  data() {    return {      freeze: false,      rolling: false,      wheelDeg: 0,      prizeNumber: 8,      prizeListOrigin: [        {          icon: "https://picsum.photos/40?random=1",          name: "$10000"        },        {          icon: "https://picsum.photos/40?random=6",          name: "Thank you!"        },                {          icon: "https://picsum.photos/40?random=2",          name: "$500"        },        {          icon: "https://picsum.photos/40?random=3",          name: "$100"        },                {          icon: "https://picsum.photos/40?random=6",          name: "Thank you!"        },        {          icon: "https://picsum.photos/40?random=4",          name: "$50"        },        {          icon: "https://picsum.photos/40?random=5",          name: "$10"        },        {          icon: "https://picsum.photos/40?random=6",          name: "Thank you!"        }      ]    };  },  computed: {    prizeList () {      return this.prizeListOrigin.slice(0, this.prizeNumber)    }  },  methods: {    onClickRotate() {      if (this.rolling) {        return;      }      this.rolling = true;      const { wheelDeg, prizeList } = this;      const random = Math.floor(Math.random() * (prizeList.length ));      console.log(random);      this.wheelDeg =        wheelDeg -        wheelDeg % 360 +        6 * 360 +        (360 - 360 / prizeList.length * random);      setTimeout(() => {        this.rolling = false;        alert("Result：" + prizeList[random].name);      }, 4500);    }  },  watch: {    prizeNumber () {      this.freeze = true      this.wheelDeg = 0           setTimeout(() => {         this.freeze = false      }, 0)    }  }};var App = Vue.extend(Main);new App().$mount("#app");

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