1.自行去下载tracking.js

npm install tracking

2.三个canvas，一个显示完整摄像头，一个在摄像头上显示人脸矩形框，一个截取人脸（提醒大家一下，如果你选择localhost运行预览是不会报错的，但是如果选择IP地址运行预览，肯定是会报错的，因为你的浏览器在不是https协议的情况下不允许打开摄像头）

<template>
  <div>
    <div>
      <p>脸部放入红色矩形框</p>
      <video id="video" style="transform: rotateY(180deg)" autoplay preload loop muted></video>
      <canvas id="overlayCanvas" width="200" height="200" style="position: absolute; top: 20; left: 0; transform: rotateY(180deg);"></canvas>
    </div>
    <div>
      <p>检测人脸结果</p>
      <canvas id="fullCanvas" width="200" height="200" style="transform: rotateY(180deg)"></canvas>
      <canvas id="faceCanvas" width="200" height="200" style="transform: rotateY(180deg); display: none;"></canvas>
    </div>
    <div>结果：{
   
   { img }}</div>
  </div>
</template>

<script>
//import { userMedia } from '../../utils/utils';
import 'tracking/build/tracking.js';
import 'tracking/build/data/face-min.js';

export default {
  data() {
    return {
      img: '',
      videoObj: null,
      trackerTask: null,
      overlayContext: null
    }
  },

  mounted() {
    this.getCompetence()
  },

  methods: {
    openCamera() {
      this.$nextTick(() => {
        const fullCanvas = document.getElementById('fullCanvas')
        const fullContext = fullCanvas.getContext('2d')

        const faceCanvas = document.getElementById('faceCanvas')
        const faceContext = faceCanvas.getContext('2d')

        this.videoObj = document.getElementById('video')

        const overlayCanvas = document.getElementById('overlayCanvas')
        this.overlayContext = overlayCanvas.getContext('2d')

        const tracker = new window.tracking.ObjectTracker('face')
        tracker.setInitialScale(4)
        tracker.setStepSize(2)
        tracker.setEdgesDensity(0.1)

        this.trackerTask = window.tracking.track('#video', tracker, { camera: true })
        this.img = this.trackerTask

        tracker.on('track', (event) => {
          if (event.data.length !== 0) {
            event.data.forEach((rect) => {
              fullContext.clearRect(0, 0, fullCanvas.width, fullCanvas.height)
              fullContext.drawImage(this.videoObj, 0, 0, fullCanvas.width, fullCanvas.height)

              faceCanvas.width = rect.width
              faceCanvas.height = rect.height
              faceContext.clearRect(0, 0, faceCanvas.width, faceCanvas.height)
              faceContext.drawImage(this.videoObj, rect.x, rect.y, rect.width, rect.height, 0, 0, faceCanvas.width, faceCanvas.height)

              // 绘制矩形框到 overlayCanvas
              this.overlayContext.clearRect(0, 0, overlayCanvas.width, overlayCanvas.height)
              this.overlayContext.strokeStyle = 'red'; // 设置矩形框颜色
              this.overlayContext.lineWidth = 2; // 设置矩形框线宽
              this.overlayContext.strokeRect(rect.x, rect.y, rect.width, rect.height)

              console.log(faceCanvas.toDataURL())
              this.img = faceCanvas.toDataURL()
            });
          }
        })
      })
    },

    getCompetence() {
      let _this = this;
      this.video = document.getElementById("video");
      if (navigator.mediaDevices === undefined) {
        navigator.mediaDevices = {};
      }
      if (navigator.mediaDevices.getUserMedia === undefined) {
        navigator.mediaDevices.getUserMedia = function (constraints) {
          var getUserMedia =
            navigator.webkitGetUserMedia ||
            navigator.mozGetUserMedia ||
            navigator.getUserMedia;
          if (!getUserMedia) {
            return Promise.reject(
              new Error("getUserMedia is not implemented in this browser")
            );
          }
          return new Promise(function (resolve, reject) {
            getUserMedia.call(navigator, constraints, resolve, reject);
          });
        };
      }
      var constraints = {
        video: { width: 200, height: 200, transform: "scaleX(-1)" },
        audio: false,
      };
      navigator.mediaDevices
        .getUserMedia(constraints)
        .then(function (stream) {
          if ("srcObject" in _this.video) {
            _this.video.srcObject = stream;
          } else {
            _this.video.src = window.URL.createObjectURL(stream);
          }
          _this.video.onloadedmetadata = function (e) {
            _this.video.play();
          };

          _this.openCamera();
        })
        .catch((err) => {
          console.log(err);
        });
    },

    de() {
      this.video.srcObject.getTracks()[0].stop();
      this.trackerTask.stop();
    },

    handleCancel() {
      this.videoObj.srcObject.getTracks()[0].stop()
      this.trackerTask.stop()
    },

    success(stream) {
      this.videoObj.srcObject = stream
      this.videoObj.play()
    },

    error(error) {
      console.log(`访问用户媒体设备失败${error.name}, ${error.message}`)
    }
  },

  beforeDestroy() {
    this.handleCancel()
  }
}
</script>