一. 安装所需依赖

npm install html2canvas --save
npm install jspdf --save

二. htmlToPdfNew.js 核心文件

/* eslint-disable */
import jsPDF from "jspdf";
import html2canvas from "html2canvas";/** 使用说明* ele:需要导出pdf的容器元素(dom节点 不是id)* pdfFileName: 导出文件的名字 通过调用outPutPdfFn方法也可传参数改变* splitClassName: 避免分段截断的类名 当pdf有多页时需要传入此参数 , 避免pdf分页时截断元素  如表格<tr class="itemClass"></tr>* 调用方式 先 let pdf = new PdfLoader(ele, 'pdf' ,'itemClass');再 pdf.outPutPdfFn()* 若想改变pdf名称 pdf.outPutPdfFn(fileName);  outPutPdfFn方法返回一个promise 可以使用then方法处理pdf生成后的逻辑* */
class PdfLoader {constructor(ele, pdfFileName, splitClassName) {this.ele = ele;this.pdfFileName = pdfFileName;this.splitClassName = splitClassName;this.A4_WIDTH = 595;this.A4_HEIGHT = 842;}async getPDF() {// debuggerlet ele = this.ele;let pdfFileName = this.pdfFileName;let eleW = ele.offsetWidth; // 获得该容器的宽let eleH = ele.scrollHeight; // 获得该容器的高let eleOffsetTop = ele.offsetTop; // 获得该容器到文档顶部的距离let eleOffsetLeft = ele.offsetLeft; // 获得该容器到文档最左的距离let canvas = document.createElement("canvas");let abs = 0;let win_in =document.documentElement.clientWidth || document.body.clientWidth; // 获得当前可视窗口的宽度（不包含滚动条）let win_out = window.innerWidth; // 获得当前窗口的宽度（包含滚动条）if (win_out > win_in) {abs = (win_out - win_in) / 2; // 获得滚动条宽度的一半}canvas.width = eleW * 2; // 将画布宽&&高放大两倍canvas.height = eleH * 2;let context = canvas.getContext("2d");context.scale(3, 3); // 增强图片清晰度context.translate(-eleOffsetLeft - abs, -eleOffsetTop);html2canvas(ele, {useCORS: true, //允许canvas画布内可以跨域请求外部链接图片, 允许跨域请求。}).then(async (canvas) => {// debuggerlet contentWidth = canvas.width;let contentHeight = canvas.height;//一页pdf显示html页面生成的canvas高度;let pageHeight = (contentWidth / this.A4_WIDTH) * this.A4_HEIGHT; // 这样写的目的在于保持宽高比例一致 pageHeight/canvas.width = a4纸高度/a4纸宽度// 宽度和canvas.width保持一致//未生成pdf的html页面高度let leftHeight = contentHeight;//页面偏移let position = 30;//a4纸的尺寸[595,842],单位像素，html页面生成的canvas在pdf中图片的宽高let imgWidth = this.A4_WIDTH - 60; //-60为了页面有左右边距  是一边30let imgHeight = (this.A4_WIDTH / contentWidth) * contentHeight;let pageData = canvas.toDataURL("image/jpeg", 1.0);let pdf = jsPDF("", "pt", "a4");//有两个高度需要区分，一个是html页面的实际高度，和生成pdf的页面高度(841.89)//当内容未超过pdf一页显示的范围，无需分页if (leftHeight < pageHeight) {//在pdf.addImage(pageData, 'JPEG', 左20，上，宽度，高度)设置在pdf中显示；pdf.addImage(pageData, "JPEG", 30, 20, imgWidth, imgHeight);// pdf.addImage(pageData, 'JPEG', 20, 40, imgWidth, imgHeight);} else {// 分页while (leftHeight > 0) {pdf.addImage(pageData, "JPEG", 30, position, imgWidth, imgHeight);leftHeight -= pageHeight;position -= this.A4_HEIGHT;//避免添加空白页if (leftHeight > 0) {pdf.addPage();}}}pdf.save(pdfFileName + ".pdf", { returnPromise: true }).then(() => {//去除添加的空div 防止页面混乱let doms = document.querySelectorAll(".emptyDiv");for (let i = 0; i < doms.length; i++) {doms[i].remove();}});this.ele.style.height = "";});}isSplit(nodes, index, pageHeight) {if (nodes[index].offsetTop + nodes[index].offsetHeight < pageHeight &&nodes[index + 1] &&nodes[index + 1].offsetTop + nodes[index + 1].offsetHeight > pageHeight) {return true;}return false;}async outPutPdfFn(pdfFileName) {// debuggerreturn new Promise((resolve, reject) => {this.ele.style.height = "initial";pdfFileName ? (this.pdfFileName = pdfFileName) : null;let target = this.ele;let pageHeight = (target.scrollWidth / this.A4_WIDTH) * this.A4_HEIGHT;// 获取分割dom，此处为class类名为item的domlet domList = document.getElementsByClassName(this.splitClassName);// 进行分割操作，当dom内容已超出a4的高度，则将该dom前插入一个空dom，把他挤下去，分割let pageNum = 1; //pdf页数let eleBounding = this.ele.getBoundingClientRect();for (let i = 0; i < domList.length; i++) {let node = domList[i];let bound = node.getBoundingClientRect();let offset2Ele = bound.top - eleBounding.top;let currentPage = Math.ceil((bound.bottom - eleBounding.top) / pageHeight); //当前元素应该在哪一页if (pageNum < currentPage) {pageNum++;let divParent = domList[i].parentNode; // 获取该div的父节点let newNode = document.createElement("div");newNode.className = "emptyDiv";newNode.style.background = "white";newNode.style.height =pageHeight * (pageNum - 1) - offset2Ele + 30 + "px"; //+30为了在换下一页时有顶部的边距newNode.style.width = "100%";let next = domList[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, node);} 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);}}}// 异步函数  再调用保存为pdf的函数// this.getPDF(resolve, reject)});}
}export default PdfLoader;

三. 组件使用方法

1. 引入 htmlToPdfNew.js 核心文件

   import PdfLoader from "./htmlToPdfNew.js";
   

2. dom 设置

   <!-- 下载事件 -->
   <button @click="downLoadPdf">下载</button>
   <!-- pdf 下载内容 -->
   <div id="pdfContainer"></div>
   

3. 下载事件方法

   downLoadPdf() {let ele = document.getElementById("pdfContainer");// pdf.outPutPdfFn(this.userName + '分析报告')let pdf = new PdfLoader(ele, "测试", "itemClass");pdf.getPDF();
   },
   

四. 组件使用实例

<template><div class="home"><!-- 下载事件 --><button @click="downLoadPdf">下载</button><!-- pdf 下载内容 --><div id="pdfContainer" class="pdfContainer"><div class="title">PDF 标题</div><div class="itemClass"></div><div class="info"><div class="text1">君不见黄河之水天上来，奔流到海不复回。</div><div class="text2">君不见高堂明镜悲白发，朝如青丝暮成雪。</div></div></div></div>
</template><script>
import PdfLoader from "./htmlToPdfNew.js";
export default {methods: {downLoadPdf() {let ele = document.getElementById("pdfContainer");// pdf.outPutPdfFn(this.userName + '分析报告')let pdf = new PdfLoader(ele, "测试", "itemClass");pdf.getPDF();},},
};
</script><style scoped lang="scss">
.home {width: 100%;height: 100%;.pdfContainer {width: 800px;padding: 10px 20px;border: 1px solid #e2e2e2;box-sizing: border-box;text-align: center;.title {text-align: center;font-weight: bold;padding-bottom: 10px;}.info {line-height: 35px;.text1 {color: rgb(0, 170, 255);}.text2 {color: rgb(255, 119, 0);}}}
}
</style>