vue实现网页截图 html2Canvas

1. 安装html2Canvas

npm i html2canvas --save

2. 引入

import html2cancas from 'html2canvas

3. 调用函数 toImage

// 页面元素转图片
        toImage () {
            // 手动创建一个 canvas 标签
            const canvas = this.$refs.canvas
            // 获取父标签，意思是这个标签内的 DOM 元素生成图片
            // imageTofile是给截图范围内的父级元素自定义的ref名称
            let canvasBox = this.$refs.imageTofile.$el
            // 获取父级的宽高
            const width = parseInt(canvasBox.offsetWidth)
            const height = parseInt(canvasBox.offsetHeight)
            // 宽高 * 2 并放大 2 倍 是为了防止图片模糊
            canvas.width = width * 2
            canvas.height = height * 2
            canvas.style.width = width + 'px'
            canvas.style.height = height + 'px'
            const context = canvas.getContext("2d");
           // context.scale(2, 2);
            const options = {
                backgroundColor: null,
                canvas: canvas,
                useCORS: true
            }
            html2canvas(canvasBox, options).then((canvas) => {
                // toDataURL 图片格式转成 base64
                let dataURL = canvas.toDataURL("image/png")
                console.log(dataURL)
                this.downloadImage(dataURL)
            })
        }
        //下载图片
        downloadImage(url) {
            // 如果是在网页中可以直接创建一个 a 标签直接下载 
            let a = document.createElement('a')
            a.href = url
            a.download = '首页截图'
            a.click()
        }
        // base64图片转成二进制文件流
        base64toFile (dataurl, filename = 'file') {
            let arr = dataurl.split(',')
            let mime = arr[0].match(/:(.*?);/)[1]
            let suffix = mime.split('/')[1]
            let bstr = atob(arr[1])
            let n = bstr.length
            let u8arr = new Uint8Array(n)
            while (n--) {
                u8arr[n] = bstr.charCodeAt(n)
            }
            return new File([u8arr], `${filename}.${suffix}`, {
                type: mime
            })
        }