浏览器播放电脑摄像头且截图例子

<template>
  <div class="camera_outer">
    <div class="video-content">
      <div>视频区域</div>
      <video
        id="videoCamera"
        :width="videoWidth"
        :height="videoHeight"
        autoplay
      ></video>
    </div>

    <canvas
      style="display: none"
      id="canvasCamera"
      :width="videoWidth"
      :height="videoHeight"
    ></canvas>

    <div  v-if="imgSrc" class="img_bg_camera">
    <div>快照图像</div>
      <img :src="imgSrc" alt="" class="tx_img" />
    </div>
    <div class="btn-group">
      <el-button type="primary" plain @click="getCompetence()"
        >打开摄像头</el-button
      >
      <el-button type="primary" plain @click="stopNavigator()"
        >关闭摄像头</el-button
      >
      <el-button type="primary" plain @click="setImage()">快照</el-button>
    </div>
  </div>
</template>
  <script>
export default {
  data() {
    return {
      videoWidth: 300,
      videoHeight: 300,
      imgSrc: "",
      thisCancas: null,
      thisContext: null,
      thisVideo: null,
    };
  },
  mounted() {
    this.getCompetence();
  },
  methods: {
    // 调用权限（打开摄像头功能）
    getCompetence() {
      var _this = this;
      this.thisCancas = document.getElementById("canvasCamera");
      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.mediaDevices = {};
      }
      // 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)
          var 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);
          });
        };
      }
      var 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;
          } 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) => {
          console.log(err);
        });
    },
    //  绘制图片（拍照功能）
    setImage() {
      var _this = this;
      // 点击，canvas画图
      _this.thisContext.drawImage(
        _this.thisVideo,
        0,
        0,
        _this.videoWidth,
        _this.videoHeight
      );
      // 获取图片base64链接
      var image = this.thisCancas.toDataURL("image/png");
      _this.imgSrc = image;
      debugger;
      this.saveBase64Image(image, `截图保存${new Date().getTime()}`);
    },
    saveBase64Image(base64Data, fileName) {
      // 将base64字符串转换为Blob对象
      const blob = this.base64ToBlob(base64Data);
      // 创建一个指向Blob对象的URL
      const objectUrl = URL.createObjectURL(blob);
      // 创建一个a标签
      const a = document.createElement("a");
      a.href = objectUrl;
      a.download = fileName;
      // 模拟a标签点击，触发下载
      document.body.appendChild(a);
      a.click();
      // 清理临时DOM和对象URL
      document.body.removeChild(a);
      URL.revokeObjectURL(objectUrl);
    },
    base64ToBlob(base64Data) {
      // 将base64字符串转换为二进制数据
      const sliceSize = 512;
      const byteCharacters = atob(base64Data.split(",")[1]);
      const byteArrays = [];
      for (
        let offset = 0;
        offset < byteCharacters.length;
        offset += sliceSize
      ) {
        const slice = byteCharacters.slice(offset, offset + sliceSize);
        const byteNumbers = new Array(slice.length);

        for (let i = 0; i < slice.length; i++) {
          byteNumbers[i] = slice.charCodeAt(i);
        }
        const byteArray = new Uint8Array(byteNumbers);
        byteArrays.push(byteArray);
      }
      // 创建Blob对象
      return new Blob(byteArrays, { type: "image/png" }); // 根据实际情况修改MIME类型
    },
    // base64转文件
    dataURLtoFile(dataurl, filename) {
      var arr = dataurl.split(",");
      var mime = arr[0].match(/:(.*?);/)[1];
      var bstr = atob(arr[1]);
      var n = bstr.length;
      var u8arr = new Uint8Array(n);
      while (n--) {
        u8arr[n] = bstr.charCodeAt(n);
      }
      return new File([u8arr], filename, { type: mime });
    },
    // 关闭摄像头
    stopNavigator() {
      this.thisVideo.srcObject.getTracks()[0].stop();
    },
  },
};
</script>
  <style lang="scss" scoped>
.camera_outer {
  position: relative;
  overflow: hidden;
  background-size: 100%;
  video,
  canvas,
  .tx_img {
    -moz-transform: scaleX(-1);
    -webkit-transform: scaleX(-1);
    -o-transform: scaleX(-1);
    transform: scaleX(-1);
  }
  .btn_camera {
    position: absolute;
    bottom: 4px;
    left: 0;
    right: 0;
    height: 50px;
    background-color: rgba(0, 0, 0, 0.3);
    line-height: 50px;
    text-align: center;
    color: #ffffff;
  }
  .bg_r_img {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    top: 0;
  }
  .img_bg_camera {
    position: absolute;
    right: 0;
    top: 0;
    img {
      width: 300px;
      height: 300px;
    }
    .img_btn_camera {
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      height: 50px;
      line-height: 50px;
      text-align: center;
      background-color: rgba(0, 0, 0, 0.3);
      color: #ffffff;
      .loding_img {
        width: 50px;
        height: 50px;
      }
    }
  }
}
.video-content{
  margin-left: 30px;
}
.btn-group {
  margin-left: 20px;
  margin-top: 20px;
}
.img_bg_camera{

}
</style>

　　效果：