介绍

需要https的支持，可将Base64或URL图片复制到黏贴版中！

    /**
     * 复制图片，接受 data: URI 和 http[s] 的图片地址
     * @param url
     * @returns {Promise<unknown>}
     */
    function image2blob (url) {
        return new Promise(resolve => {
            // 如果是 data 开头的就使用 DataURI 的解析
            if (url.indexOf('data:') === 0) {
                return resolve(new ClipboardItem({ 'image/png': dataURItoBlob(url) }))
            }
            const img = new Image
            const c = document.createElement('canvas')
            const ctx = c.getContext('2d')

            img.onload = function () {
                c.width = this.naturalWidth
                c.height = this.naturalHeight
                ctx.drawImage(this, 0, 0)
                c.toBlob(blob => resolve(new ClipboardItem({ 'image/png': blob })), 'image/png', 1)
            }

            img.crossOrigin = ''
            img.src = url
        })

    }

    /**
     * 将 data: 开头的 dataURI base64 图片转为 blob
     * @param dataURI
     * @returns {Blob}
     */
    function dataURItoBlob (dataURI) {
        var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0] // mime类型
        var byteString = atob(dataURI.split(',')[1]) //base64 解码
        var arrayBuffer = new ArrayBuffer(byteString.length) //创建缓冲数组
        var intArray = new Uint8Array(arrayBuffer) //创建视图

        for (var i = 0; i < byteString.length; i++) {
            intArray[i] = byteString.charCodeAt(i)
        }
        return new Blob([intArray], { type: mimeString })
    }

    /**
     * 复制图片
     * @param url
     * @returns {Promise<unknown>}
     */
    function copyImage (url) {
        return new Promise((resolve, reject) => {
            image2blob(url).then(data => {
                navigator.clipboard.write([data]).then(resolve, reject)
            })
        })
    }

    window.onload = function () {
        if (!document.hasFocus()) {
            alert('必须窗口获得焦点')
            return
        }

        copyImage(...).then(() => alert('复制成功'), (e) => alert(e))
    }