导出pdf

该方法导出的pdf大小是A4纸的尺寸，如果大于1页需要根据元素高度进行截断的话，页面元素需要加 class ergodic-dom，方法里面会获取ergodic-dom元素，对元素高度和A4高度做比较，如果大于A4高度，会塞一个空白元素，确保每一个元素在换页的时候不会被分割。

import exportPDFMixin from '@/mixins/exportPDFMixin';
mixins: [exportPDFMixin],

 <span v-show="showEdit" class="export textR" @click="exportPDF('pdfDom', '导出的pdf名称')">导出</span>

//exportPDFMixin.js
import html2Canvas from 'html2canvas';
import JsPDF from 'jspdf';
export default {data() {return {showEdit: true}},methods: {exportPDF(elId, title = "pdf") {this.showEdit = false;this.$nextTick(() => {this.downloadPDF(elId, title);})},downloadPDF(elId, title) {html2Canvas(document.querySelector(`#${elId}`), {allowTaint: true,useCORS: true,onclone: (documentclone) => {this.formatNode(documentclone);}}).then((canvas) => {let contentWidth = canvas.widthlet contentHeight = canvas.heightlet pageHeight = contentWidth / 592.28 * 841.89let leftHeight = contentHeightlet position = 0let imgWidth = 595.28let imgHeight = 592.28 / contentWidth * contentHeightlet pageData = canvas.toDataURL('image/jpeg', 1.0)let PDF = new JsPDF('', 'pt', 'a4')if (leftHeight < pageHeight) {PDF.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight)} else {while (leftHeight > 0) {PDF.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight)leftHeight -= pageHeightposition -= 841.89if (leftHeight > 0) {PDF.addPage()}}}PDF.save(title + '.pdf');this.showEdit = true;})},formatNode(documentclone) {let pageHeight = documentclone.querySelector("#pdfDom").scrollWidth / 592.28 * 841.89;let lableListID = documentclone.getElementsByClassName('ergodic-dom');for (let i = 0; i < lableListID.length; i++) {let multiple = Math.ceil((lableListID[i].offsetTop + lableListID[i].offsetHeight) / pageHeight)if (this.isSplit(lableListID, i, multiple * pageHeight)) {let divParent = lableListID[i].parentNode // 获取该div的父节点let _H = multiple * pageHeight - (lableListID[i].offsetTop + lableListID[i].offsetHeight)let newNode = this.getFooterElement(_H)let next = lableListID[i].nextSibling // 获取div的下一个兄弟节点// 判断兄弟节点是否存在if (next) {// 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divParent.insertBefore(newNode, next)} else {// 不存在则直接添加到最后,appendChild默认添加到divParent的最后divParent.appendChild(newNode)}}}},getFooterElement (remainingHeight, fillingHeight = 85) {let newNode = document.createElement('div')newNode.style.background = '#fff'newNode.style.width = 'calc(100% + 8px)'newNode.style.marginLeft = '-4px'newNode.style.marginBottom = '0px'newNode.style.height = (remainingHeight + fillingHeight) + 'px' // pdf截断需要一个空白位置return newNode},isSplit (nodes, index, pageHeight) {return nodes[index].offsetTop + nodes[index].offsetHeight < pageHeight && nodes[index + 1] && nodes[index + 1].offsetTop + nodes[index + 1].offsetHeight > pageHeight},}
}