先写一个按钮控制显示摄像头的弹窗打开

<template>
  <div>
    <el-button size="small" @click="handleOpen">拍照 <i class="el-icon-camera el-icon--right"></i></el-button>

    <el-dialog title="拍照" :visible.sync="cameraDialog" @close="closeclick" :close-on-click-modal="false" v-if="cameraDialog" width="600px">
      <div class="camera-box" v-loading="loading">
        <div class="camera-left">
          <!-- 这里就是摄像头显示的画面 -->
          <video id="videoCamera" width="100%" height="100%"></video>
        </div>
        <div class="camera-right">
      
          <div class="camera-img-box">
            <div class="small-img">
              <!-- 这里是点击拍照显示的图片画面 -->
              <img v-if="imgSrc" :src="imgSrc" style="width: 200px;height: 150px;" />
              <canvas id="canvasCamera" class="canvas" :width='videoWidth' :height='videoHeight' style="display: none;"></canvas>
            </div>
            <div>
            <!-- 点击拍照和保存按钮 -->
              <el-button type="primary" class="save-camera-btn" icon="el-icon-camera" @click="drawImage" style="margin-top: 10px;">拍照</el-button>
              <el-button type="primary" class="save-camera-btn" icon="el-icon-check" @click="uploadPicture">保存</el-button>
            </div>
          </div>
        </div>
      </div>
    </el-dialog>
  </div>
</template>

调用摄像头的方法

  data() {
    return {
      //相机
      cameraDialog:false,
      os: false,//控制摄像头开关
      imgSrc: undefined,
      thisVideo: null,
      thisContext: null,
      thisCancas: null,
      videoWidth: 500,
      videoHeight: 300,
      loading:true,
    };
  },
methods: {
    //拍照
    handleOpen(){
      this.loading = true;
      this.cameraDialog = true;
      this.getCompetence();
    },
    getCompetence() {
      //必须在model中render后才可获取到dom节点,直接获取无法获取到model中的dom节点
      this.$nextTick(() => {
        const _this = this;
        this.os = false;//切换成关闭摄像头
        this.thisCancas = document.getElementById('canvasCamera');//这里是需要截取的canvas的Id名称
        this.thisContext = this.thisCancas.getContext('2d');
        this.thisVideo = document.getElementById('videoCamera');
        // 旧版本浏览器可能根本不支持mediaDevices，我们首先设置一个空对象
        if (navigator.mediaDevices === undefined) {
          navigator.menavigatordiaDevices = {}
        }
        // 一些浏览器实现了部分mediaDevices，我们不能只分配一个对象
        // 使用getUserMedia，因为它会覆盖现有的属性。
        // 这里，如果缺少getUserMedia属性，就添加它。
        if (navigator.mediaDevices.getUserMedia === undefined) {
          navigator.mediaDevices.getUserMedia = function (constraints) {
            // 首先获取现存的getUserMedia(如果存在)
            let getUserMedia = navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.getUserMedia;
            // 有些浏览器不支持，会返回错误信息
            // 保持接口一致
            if (!getUserMedia) {
              return Promise.reject(new Error('getUserMedia is not implemented in this browser'))
            }
            // 否则，使用Promise将调用包装到旧的navigator.getUserMedia
            return new Promise(function (resolve, reject) {
              getUserMedia.call(navigator, constraints, resolve, reject)
            })
          }
        }
        const constraints = {
          audio: false,
          video: {width: _this.videoWidth, height: _this.videoHeight, transform: 'scaleX(-1)'}
        };
        navigator.mediaDevices.getUserMedia(constraints).then(function (stream) {
          // 旧的浏览器可能没有srcObject
          if ('srcObject' in _this.thisVideo) {
            _this.thisVideo.srcObject = stream
            _this.loading = false;
          } else {
            // 避免在新的浏览器中使用它，因为它正在被弃用。
            _this.thisVideo.src = window.URL.createObjectURL(stream)
          }
          _this.thisVideo.onloadedmetadata = function (e) {
            _this.thisVideo.play()
          }
        }).catch(err => {
          this.$notify({
            title: '警告',
            message: '没有开启摄像头权限或浏览器版本不兼容.',
            type: 'warning'
          });
        });
      });
    },
    //绘制图片
    drawImage() {
      // 点击，canvas画图
      this.thisContext.drawImage(this.thisVideo, 0, 0, this.videoWidth, this.videoHeight);
      // 获取图片base64链接，展示到界面中的也是这个url地址
      this.imgSrc = this.thisCancas.toDataURL('image/png');
       
    },
    // 上传照相机图片
     uploadPicture() {
       // 这里就调用上传图片接口即可
     },
    //清空画布
    clearCanvas(id) {
      let c = document.getElementById(id);
      let cxt = c.getContext("2d");
      cxt.clearRect(0, 0, c.width, c.height);
    },
    //重置画布
    resetCanvas() {
      this.imgSrc = "";
      this.clearCanvas('canvasCamera');
    },
    //关闭摄像头
    stopNavigator() {
      if (this.thisVideo && this.thisVideo !== null) {
        this.thisVideo.srcObject.getTracks()[0].stop();
        this.os = true;//切换成打开摄像头
      }
    },
    //关闭弹窗
    closeclick(){
      this.cameraDialog = false; // 关闭照相机弹窗
      this.resetCanvas(); // 重置画布
      this.stopNavigator(); // 关闭摄像头
    }
}