vue视频截图设置

参考地址内容：https://my.oschina.net/odetteisgorgeous/blog/3186737
参考地址内容：https://zhuanlan.zhihu.com/p/87313900

<template>
    <div class="videoDiv">
        <video class="video" src="./video1.mp4" autoplay controls='controls'></video>
        <button @click="snapshot">截图</button>
        <div>
            <img v-if="imgUrl" :src="imgUrl" alt="" class="img" id="imgId">
        </div>
        <button v-if="imgUrl" @click="downloadImage">下载</button>
        
        <canvas style="display:none;width:600px;height:400px;"></canvas>
    </div>
</template>

<script>
export default {
    
    
    data () {
    
    
        return {
    
    
            imgUrl: ''
        }
    },
    mounted () {
    
    
       
    },
    methods: {
    
    
        // 截图下载 
        downloadImage() {
    
    
            var a = document.createElement('a');
            a.setAttribute('href', this.imgUrl);
            a.setAttribute('target', '_blank');
            a.setAttribute('id', 'vid');
            a.setAttribute('download', "image"+ (+new Date()) +".jpeg");
            let canSupportDownload ='download'in a;
            // 防止反复添加
            if (document.getElementById('vid')) {
    
    
                document.body.removeChild(document.getElementById('vid'));
            }

            if (canSupportDownload) {
    
    
                document.body.appendChild(a);
                a.click();
            } else {
    
    
                alert("不支持下载");
                window.open(url);
            }

        },
        
        // 点击截图
        snapshot() {
    
    
            var video = document.querySelectorAll("video")[0]; //获取前台要截图的video对象，
            var canvas = document.querySelectorAll('canvas')[0]; //获取前台的canvas对象，用于作图

            var w = parseInt(window.getComputedStyle(video).width);

            var h = parseInt(window.getComputedStyle(video).height);
            // 为了将canvas画布放大若干倍，然后盛放在较小的容器内，就显得不模糊了
            canvas.width = w * 4;
            canvas.height = h * 4;
            canvas.style.width = w + "px";
            canvas.style.height = h + "px";
            var ctx = canvas.getContext('2d'); //设置canvas绘制2d图，
            
            ctx.drawImage(video, 0, 0, canvas.width, canvas.height); //将video视频绘制到canvas中
            // jpeg canvas.toDataURL('image/jpeg', 1)
            var images = canvas.toDataURL('image/png'); //canvas的api中的toDataURL()保存图像
            // console.log(images)
            this.imgUrl = images

            let blob = this.dataURLtoFile(this.imgUrl)
            // 文件file
            console.log(blob)
            //再包装一下
            let formData = new FormData();    
            formData.set("file", blob);
        },

        //base64转化为blob
        dataURItoBlob(base64Data) {
    
    
            var byteString;
            if(base64Data.split(',')[0].indexOf('base64') >= 0)
                byteString = atob(base64Data.split(',')[1]);
            else{
    
    
                byteString = unescape(base64Data.split(',')[1]);
            }
            var mimeString = base64Data.split(',')[0].split(':')[1].split(';')[0];
            var ia = new Uint8Array(byteString.length);
            for(var i = 0; i < byteString.length; i++) {
    
    
                ia[i] = byteString.charCodeAt(i);
            }
            var blob = new Blob([ia], {
    
    
                type: mimeString
            });
            return blob;
        },
        // 生成为文件类型
        dataURLtoFile(dataurl, filename) {
    
    
            let arr = dataurl.split(',')
            let mime = arr[0].match(/:(.*?);/)[1];
            if(!filename) {
    
    //若无文件名则取当前时间戳
                filename = Date.parse(new Date()) + '.png';
            }
            let bstr = atob(arr[1])
            let n = bstr.length
            let u8arr = new Uint8Array(n);
            while(n--){
    
    
                u8arr[n] = bstr.charCodeAt(n);
            }
            return new File([u8arr], filename, {
    
    type:mime});
        },
    }
}
</script>

<style scoped>
    .video {
    
    
        width: 600px;
        height: 400px;
    }
    .img {
    
    
        width: 600px;
        /* height: 400px; */
    }
</style>