PC端VUE使用视像头拍照

<template>
    <div class="camera_outer">
        <video id="videoCamera" :width="videoWidth" :height="videoHeight" autoplay></video>
        <canvas style="display: none" id="canvasCamera" :width="videoWidth" :height="videoHeight"></canvas>
        <div v-if="imgSrc" class="img_bg_camera">
            <p>效果预览</p>
            <img :src="imgSrc" alt class="tx_img" />
        </div>
        <div class="button">
            <el-button @click="getCompetence()" type="primary">打开摄像头</el-button>
            <el-button @click="stopNavigator()" type="warning">关闭摄像头</el-button>
            <el-button @click="setImage()" type="success">拍照</el-button>
        </div>
    </div>
</template>
<script>
    export default {
        data() {
            return {
                videoWidth: 250,
                videoHeight: 350,
                imgSrc: "",
                thisCancas: null,
                thisContext: null,
                thisVideo: null,
                openVideo: false,
            };
        },
        mounted() {
            this.getCompetence(); //进入页面就调用摄像头
        },
        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");
                _this.thisVideo.style.display = "block";
                // 获取媒体属性，旧版本浏览器可能不支持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) {
                            //不存在则报错
                            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;
                // 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; //赋值并预览图片
            },

            // 关闭摄像头
            stopNavigator() {
                this.thisVideo.srcObject.getTracks()[0].stop();
            },

            // base64转文件，此处没用到
            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 });
            },
        },
    };
</script>