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import html2Canvas from 'html2canvas'
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import JsPDF from 'jspdf'
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var noTableHeight = 0 //table外的元素高度
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export const htmlPdf = (title, html, fileList, type) => {
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return new Promise((resolve, reject) => {
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if (fileList) {
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const pageHeight = Math.floor(277 * html.scrollWidth / 190) + 20 // 计算pdf高度
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for (let i = 0; i < fileList.length; i++) { // 循环获取的元素
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const multiple = Math.ceil((fileList[i].offsetTop + fileList[i].offsetHeight) / pageHeight) // 元素的高度
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if (isSplit(fileList, i, multiple * pageHeight)) { // 计算是否超出一页
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var _H = '' // 向pdf插入空白块的内容高度
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if (fileList[i].localName !== 'tr') { // 判断是不是表格里的内容
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_H = multiple * pageHeight - (fileList[i].offsetTop + fileList[i].offsetHeight)
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} else {
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_H = multiple * pageHeight - (fileList[i].offsetTop + fileList[i].offsetHeight + noTableHeight) + 20
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}
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var newNode = getFooterElement(_H) // 向pdf插入空白块的内容
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const divParent = fileList[i].parentNode // 获取该div的父节点
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const next = fileList[i].nextSibling // 获取div的下一个兄弟节点
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// 判断兄弟节点是否存在
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if (next) {
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// 存在则将新节点插入到div的下一个兄弟节点之前，即div之后
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divParent.insertBefore(newNode, next)
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} else {
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// 否则向节点添加最后一个子节点
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divParent.appendChild(newNode)
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}
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}
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}
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}
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html2Canvas(html, {
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allowTaint: false,
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taintTest: false,
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logging: false,
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useCORS: true,
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dpi: window.devicePixelRatio * 1,
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scale: 1 // 按比例增加分辨率
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}).then(canvas => {
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var pdf = new JsPDF('l', 'mm', 'a4') // A4纸，横向或纵向
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var ctx = canvas.getContext('2d')
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var a4w = type ? 277 : 190; var a4h = type ? 190 : 277 // A4大小
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var imgHeight = Math.floor(a4h * canvas.width / a4w) // 按A4显示比例换算一页图像的像素高度
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var renderedHeight = 0
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while (renderedHeight < canvas.height) {
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var page = document.createElement('canvas')
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page.width = canvas.width
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page.height = Math.min(imgHeight, canvas.height - renderedHeight)// 可能内容不足一页
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// 用getImageData剪裁指定区域，并画到前面创建的canvas对象中
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page.getContext('2d').putImageData(ctx.getImageData(0, renderedHeight, canvas.width, Math.min(imgHeight, canvas.height - renderedHeight)), 0, 0)
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pdf.addImage(page.toDataURL('image/jpeg', 1.0), 'JPEG', 10, 10, a4w, Math.min(a4h, a4w * page.height / page.width)) // 添加图像到页面
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renderedHeight += imgHeight
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if (renderedHeight < canvas.height) {
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pdf.addPage()// 如果后面还有内容，添加一个空页
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}
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}
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// 返回Blob对象而不是直接下载文件
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const pdfBlob = pdf.output('blob');
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resolve(pdfBlob);
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}).catch(error => {
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reject(error);
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});
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});
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}
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// pdf截断需要一个空白位置来补充
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const getFooterElement = (remainingHeight, fillingHeight = 0) => {
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const newNode = document.createElement('div')
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newNode.style.background = '#ffffff'
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newNode.style.width = 'calc(100% + 8px)'
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newNode.style.marginLeft = '-4px'
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newNode.style.marginBottom = '0px'
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newNode.classList.add('divRemove')
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newNode.style.height = (remainingHeight + fillingHeight) + 'px'
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return newNode
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}
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const isSplit = (nodes, index, pageHeight) => {
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if (nodes[index].localName !== 'tr') { // 判断元素是不是tr
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noTableHeight += nodes[index].clientHeight
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}
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if (nodes[index].localName !== 'tr') {
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return nodes[index].offsetTop + nodes[index].offsetHeight < pageHeight && nodes[index + 1] && nodes[index + 1].offsetTop + nodes[index + 1].offsetHeight > pageHeight
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} else {
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return nodes[index].offsetTop + nodes[index].offsetHeight + noTableHeight < pageHeight && nodes[index + 1] && nodes[index + 1].offsetTop + nodes[index + 1].offsetHeight + noTableHeight > pageHeight
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}
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}
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