video生成封面图

根据video生成封面图，vedio要的url要允许跨域，可以设置nginx代理服务器来做

let video = document.createElement('video');

/**
 * 创建视频
*/
export const createVideo = (src) => {
    video.setAttribute('height', '110');
    video.setAttribute('width', '110');
    video.setAttribute('preload', 'auto');
    video.setAttribute('src', src);
    video.setAttribute('x-webkit-airplay', "allow");
    video.setAttribute('autoplay', 'true');
    video.setAttribute('crossOrigin', 'anonymous');
    return video;
}

/**
 * 获取视频封面图
*/
export const captureImage = (videoEle) => {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            const canvas = document.createElement('canvas')
            let imgWidth = videoEle.videoWidth;
            let imgHeight = videoEle.videoHeight;
            videoEle.addEventListener('timeupdate', () => {
                canvas.getContext('2d').drawImage(videoEle, 0, 0, imgWidth, imgHeight);
                const dataUrl = canvas.toDataURL('image/png');
                videoEle.pause()
                resolve(dataUrl);
            }, false)
        }, 1000)
    })
}

export const getImageByVideo = (url) => {
    return captureImage(createVideo(url))
}