小程序 大转盘 抽奖 canvas animation

项目需求运用到大转盘 可设置概率 可直接自定义结果 效果如下 

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两种方法及结合法

一 通过canvas 实现 但是因为定时器原因 手机端卡顿严重 故而最终使用了方法二 但也是该记录下 学习canvas

二 通过小程序Api animation完成完美解决卡顿问题 更精确定位 有样式缺陷 css无法解决样式 自动分配问题 故结合一二两种方法 出现第三种

三 通过小程序Api animation 做动画旋转 样式用canvas来实现 完美解决各类问题 

话不多说踩坑部分 就不展示 直接上第三种方法

创建动画区域 （animation） 动画可参考小程序官方API animationData动画参数 在点击开始的时候填充数据

<view class="wrapper-content" style='margin:0 auto;'>
  <view class="canvas-container">
    <view animation="{{animationData}}" class="canvas-content" style='margin:0 auto;'>    
    </view>
  </view>
</view>
//CSS

.wrapper-content{
  background: #E0CFBC;
  border-radius: 50%;
  width: 720rpx;
  height: 720rpx;
  padding: 40rpx;
  position: relative;
  box-sizing: border-box;
  z-index: 101;
}
.canvas-container {
  margin: 0 auto;
  position: absolute;
  left: 40rpx;
  top: 40rpx;
  width: 640rpx;
  height: 640rpx;
  border-radius: 50%;
}
.canvas-content {
  overflow: hidden;
  box-sizing: content-box;
  border: 20rpx solid #CDB193;
  position: absolute;
  left: 0;
  top: 0;
  z-index: 1;
  display: block;
  width: 600rpx;
  height: 600rpx;
  border-radius: inherit;
  background-clip: padding-box;
}

配合CSS3 扇形实现圆盘

html

 <!-- 扇形 -->
              <view class="canvas-list">
                <view class="canvas-item2" wx:for="{{awardsConfig.slicePrizes}}" wx:key="key" style="transform: rotate({{item.item2Deg}});background-color:{{awardsConfig.slicePrizes.length==2?(index%2==0?'#faf5e7':'#f3e2c6'):''}};opacity:{{  awardsConfig.slicePrizes.length==2?item.opacity:  awardsConfig.slicePrizes.length==3?item.opacity:''}};{{size}}rpx;height:{{size/2-2}}rpx;transform-origin:{{size/2}}rpx {{size/2}}rpx">
                  <view class="canvas-item2-after" style="transform: rotate({{item.afterDeg}});background-color:{{index%2==0?'#faf5e7':'#f3e2c6'}};opacity:{{  awardsConfig.slicePrizes.length==3?'':item.opacity}};{{size/2}}rpx;height:{{size/2}}rpx;transform-origin: {{size/2}}rpx {{size/2}}rpx">
                  </view>
                  <view wx:if='{{awardsConfig.slicePrizes.length==3}}' class="canvas-item2-after" style="background-color:{{index%2==0?'#faf5e7':'#f3e2c6'}};{{size/2}}rpx;height:{{size/2}}rpx;transform-origin: {{size/2}}rpx {{size/2}}rpx"></view>
                </view>
              </view>
              <!-- 选项内容 -->
              <view class="wk-wheel-list">
                <view class="wk-wheel-item" data-index="{{index}}" wx:for="{{awardsConfig.slicePrizes}}" wx:key='key'>
                  <view class="wk-wheel-icontent" style="height:262rpx;overflow:hidden;font-size:{{item.text.length>9?'20':'26'}}rpx;padding-top:5rpx;transform: rotate({{index*turnNum}}turn);transform-origin: 50% {{size/2-2}}rpx">
                    <view class="canvas-litem-text-name">{{item.text}}</view>
                    <view class="canvas-litem-text-image">
                      <image src="{{item.img}}" mode="widthFix" style="80rpx;max-height:60rpx;padding:10rpx 0 0;"></image>
                      <view class="canvas-litem-text-image-num">100</view>
                    </view>
                    <view style="font-size:20rpx;">{{item.num}}x1</view>
                  </view>
                </view>
              </view>
            </view>

CSS

/* //css扇形 */
.canvas-item2 {
   position: absolute;
   left: 0px;
   top: 0;
   width: 620rpx;
   height: 328rpx;
   color: #e4370e;
   font-weight: bold;
   transform-origin: 330rpx 330rpx;
   overflow: hidden;
}
 
.canvas-item2-after {
   position: absolute;
   top: 0;
   left: 0;
   width: 330rpx;
   height: 330rpx;
   transform-origin: 330rpx 330rpx;
   opacity: 1;
}
 
.wk-wheel-list {
   position: absolute;
   left: 0;
   top: 0;
   width: 100%;
   height: 100%;
   z-index: 9;
}
 
.wk-wheel-item {
   position: absolute;
   left: 0;
   top: 0;
   width: 100%;
   height: 100%;
   color: #fff;
   text-shadow: 0 1px 1px rgba(255, 255, 255, 0.6);
}
 
.wk-wheel-icontent {
   position: relative;
   display: block;
   padding-top: 50rpx;
   margin: 0 auto;
   text-align: center;
   transform-origin: 50% 328rpx;
   color: #AA8B6B;
}

1.awardsConfig.slicePrizes为奖品列表  因为大转盘是圆的 所以W H 是一样的 

2.this.data.windowWidth 是屏幕的宽度 小程序有API 可以获取  用屏幕宽度/750*设置内容宽度rpx = 实际内容宽度的px 值

3.size 是圆盘的宽度

设置点击抽奖按钮 两种方法 一直接在canvas内绘制  二在HTML里面通过定位实现

提供二 HTML 定位实现按钮

<view class="canvas-btn" bindtap="getLottery">
         <view>
            <view style="font-size:56rpx;color:#fff;padding-bottom:4rpx;">开始</view>
            <view style="font-size:20rpx;color:#6F5942;font-weight:600;">点击抽奖</view>
          </view>
</view>

css

.canvas-btn {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  position: absolute;
  left: 50%;
  top: 50%;
  margin-left: -110rpx;
  margin-top: -110rpx;
  z-index: 400;
  width: 220rpx;
  height: 220rpx;
  border-radius: 50%;
  color: #f4e9cc;
  border: 10px solid #cdb193;
  text-align: center;
  font-size: 40rpx;
  text-decoration: none;
  box-sizing: border-box;
}

.canvas-btn>view {
  position: absolute;
  top: 7%;
  left: 7%;
  width: 86%;
  height: 86%;
  border-radius: 50%;
  box-sizing: border-box;
  padding: 22rpx 20rpx 0;
  background: linear-gradient(134deg, rgba(232, 219, 197, 1) 0%, rgba(205, 177, 147, 1) 100%);
  /* box-shadow:0px 5px 7px 0px rgba(255,255,255,1); */
  margin: auto;
  z-index: 102;
}

.canvas-btn::after {
  position: absolute;
  display: block;
  content: ' ';
  left: 39%;
  top: -78%;
  width: 0;
  height: 0;
  overflow: hidden;
  border-width: 80rpx 20rpx 80rpx 20rpx;
  border-style: solid;
  border-color: transparent;
  border-bottom-color: #ffab52;
}

js

getLottery() {
    let that = this;
    // 获取奖品配置
    let awardsConfig = that.data.awardsConfig,
        runNum = 12, len = awardsConfig.slicePrizes.length,
        awardIndex = 0;
    awardIndex = parseInt(Math.random() * 6)
    console.log("奖品序号：" + awardIndex);
    // 旋转抽奖
    app.runDegs = app.runDegs || 0
    app.runDegs = app.runDegs + (360 - app.runDegs % 360) + (360 * runNum - awardIndex * (360 / len))
    //创建动画
    let animationRun = wx.createAnimation({
      duration: 4000,
      timingFunction: 'ease'
    })
    console.log(awardsConfig.slicePrizes[awardIndex]);
    that.animationRun = animationRun
    animationRun.rotate(app.runDegs - (360 / len * 2 + (360 / len)) ).step()
    that.setData({
      animationData: animationRun.export()
    })
  },

点击按钮触发getLottery 进行动画数据填充 实现旋转效果  runNum为旋转的圈数 awardIndex为中奖的序号

---

整体如此完美实现献上整体代码

html

<view class="wrapper-content" style='margin:0 auto;'>
          <view class="canvas-container-quiu" wx:for="{{list}}" style="-webkit-transform: rotate({{index * (360/list.length)}}deg);transform: rotate({{index * (360/list.length)}}deg);{{index%2==0?'background:#F2E86D':'background:#ffffff'}}"></view>
          <view class="canvas-container">
            <view animation="{{animationData}}" class="canvas-content" style='margin:0 auto;'>
            <canvas class="canvas-line" disable-scroll="true" bindtouchstart="canvasTouchStart" bindtouchmove="touchMove" bindtouchend="canvasTouchEnd" canvas-id="canvas"></canvas>
            </view>
            <view class="canvas-btn" bindtap="getLottery">
              <view>
                <view style="font-size:56rpx;color:#fff;padding-bottom:4rpx;">开始</view>
                <view style="font-size:20rpx;color:#6F5942;font-weight:600;">点击抽奖</view>
              </view>
            </view>
          </view>
        </view>

css

.wrapper-content{
  background: #E0CFBC;
  border-radius: 50%;
  width: 720rpx;
  height: 720rpx;
  padding: 40rpx;
  position: relative;
  box-sizing: border-box;
  z-index: 101;
}
.canvas-container ul, .canvas-container li {
  margin: 0;
  padding: 0;
  list-style: none;
}

.canvas-container {
  margin: 0 auto;
  position: absolute;
  left: 40rpx;
  top: 40rpx;
  width: 640rpx;
  height: 640rpx;
  border-radius: 50%;
}
.canvas-container-quiu{
  width: 20rpx;
  height: 20rpx;
  border-radius: 50%;
  position: absolute;
  left:10rpx;
  top: 50%;
  margin-top: -8rpx;
  -webkit-transform-origin: 330rpx 50%;
  transform-origin: 350rpx 50%;
   z-index: 1001;
}
.canvas-content {
  overflow: hidden;
  box-sizing: content-box;
  border: 20rpx solid #CDB193;
  position: absolute;
  left: 0;
  top: 0;
  z-index: 1;
  display: block;
  width: 600rpx;
  height: 600rpx;
  border-radius: inherit;
  background-clip: padding-box;
}
.canvas-btn {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  position: absolute;
  left: 50%;
  top: 50%;
  margin-left: -110rpx;
  margin-top: -110rpx;
  z-index: 400;
  width: 220rpx;
  height: 220rpx;
  border-radius: 50%;
  color: #f4e9cc;
  border: 10px solid #cdb193;
  text-align: center;
  font-size: 40rpx;
  text-decoration: none;
  box-sizing: border-box;
}

.canvas-btn>view {
  position: absolute;
  top: 7%;
  left: 7%;
  width: 86%;
  height: 86%;
  border-radius: 50%;
  box-sizing: border-box;
  padding: 22rpx 20rpx 0;
  background: linear-gradient(134deg, rgba(232, 219, 197, 1) 0%, rgba(205, 177, 147, 1) 100%);
  /* box-shadow:0px 5px 7px 0px rgba(255,255,255,1); */
  margin: auto;
  z-index: 102;
}

.canvas-btn::after {
  position: absolute;
  display: block;
  content: ' ';
  left: 39%;
  top: -78%;
  width: 0;
  height: 0;
  overflow: hidden;
  border-width: 80rpx 20rpx 80rpx 20rpx;
  border-style: solid;
  border-color: transparent;
  border-bottom-color: #ffab52;
}

js

var app = getApp()
var utils = require('../../utils/utils.js');
var Animation = require('../../utils/Animation.js');
var Wheel = require('../../utils/Wheel.js');
Page({

  /**
   * 页面的初始数据
   */
  data: {
    awardsList: {},
    list: [],
    statusBarHeight: getApp().globalData.statusBarHeight,
    scrollHeight: 200,
    windowWidth:0,
    windowHeight:0,
    awardsConfig: {
      count: 50,
      slicePrizes: [
        { text: "恭喜中大奖", img: "/assets/coupon_gold.png", title: "积分券x1", num: "1200", x: "1" },
        { text: "医疗服务费", img: "/assets/coupon_gold.png", title: "积分券x1", num: "50", x: "2" },
        { text: "健康保养费", img: "/assets/coupon_gold.png", title: "积分券x1", num: "500", x: "1" },
        { text: "谢谢参与", img: "/assets/coupon_gold.png", title: "积分券x3", num: "0", x: "2" },
        { text: "青春补偿费", img: "/assets/coupon_gold.png", title: "积分券x1", num: "200", x: "1" },
        { text: "感恩奉献费", img: "/assets/coupon_gold.png", title: "积分券x1", num: "100", x: "2" },
        { text: "咨询售后费", img: "/assets/coupon_gold.png", title: "积分券x1", num: "150", x: "1" },
        { text: "谢谢参与", img: "/assets/coupon_gold.png", title: "积分券x1", num: "0", x: "1" }, { text: "咨询售后费", img: "/assets/coupon_gold.png", title: "积分券x1", num: "150", x: "1" },
        { text: "谢谢参与", img: "/assets/coupon_gold.png", title: "积分券x1", num: "0", x: "1" }
      ],
    },
  },
  /**
   * 生命周期函数--监听页面加载
   */
  onLoad: function(options) {
    var that = this;
    that.initAdards()
    wx.getSystemInfo({
      success: function (res) {
        that.setData({
          windowWidth: res.windowWidth,
          windowHeight: res.windowHeight,
          scrollHeight: res.windowHeight - res.windowWidth / 750 * (getApp().globalData.statusBarHeight * 2 + 98)
        });
      },
    })
  },
  onReady: function(e) {
    let that = this,
      fps = 60, awardsConfig = that.data.awardsConfig,
        w = this.data.windowWidth / 750 * 600,
        h = this.data.windowWidth / 750 * 600,
        ;
   
    
    wx.getSystemInfo({
      success: function(res) {
        that.setData({
          contentHeight: res.windowHeight
        });
      },
    })
    that.setData({
      count: awardsConfig.count
    })
    let len = awardsConfig.slicePrizes.length,
        rotateDeg = 360 / len / 2 ,
        list = [],
        turnNum = 1 / len;
    for (var i = 0; i < len; i++) {
      list.push({
        award: awardsConfig.slicePrizes[i].text,
      });
    };
    that.setData({
      list: list.concat(list)
    });
  },
//初始化奖品数据 计算角度
  initAdards() {
    var that = this,
      awardsConfig = that.data.awardsConfig;
    var t = awardsConfig.slicePrizes.length; // 选项长度
    var e = 1 / t,
      i = 360 / t,
      r = i - 90;

    for (var g = 0; g < t; g++) {
      awardsConfig.slicePrizes[g].item2Deg = g * i + 90 - i / 2 + "deg"; //当前下标 * 360/长度 + 90 - 360/长度/2
      awardsConfig.slicePrizes[g].afterDeg = r + "deg";
      awardsConfig.slicePrizes[g].opacity = '1';
    }
    that.setData({
      turnNum: e, // 页面的单位是turn
      awardsConfig: awardsConfig,
    })
  },
  /**
  * 抽奖处理函数：
  */
  getLottery: function () {
    let that = this;
    // 获取奖品配置
    let awardsConfig = that.data.awardsConfig,
      runNum = 12,
      len = awardsConfig.slicePrizes.length,
      awardIndex = 0;
    awardIndex = parseInt(Math.random() * 6)
    console.log("奖品序号：" + awardIndex);
    // 旋转抽奖
    app.runDegs = app.runDegs || 0
    app.runDegs = app.runDegs + (360 - app.runDegs % 360) + (360 * runNum - awardIndex * (360 / len))
    //创建动画
    let animationRun = wx.createAnimation({
      duration: 4000,
      timingFunction: 'ease'
    })
    console.log(awardsConfig.slicePrizes[awardIndex]);
    that.animationRun = animationRun
    animationRun.rotate(app.runDegs).step()
    that.setData({
      animationData: animationRun.export()
    })
  },
})

​​​