js
复制代码
import htmlToPdffrom './index.js'
const suc = () => {
message.success('success');
};
//记得在需要打印的div上面添加 id
let dom = document.querySelector('#testPdf');
let pdf = new htmlToPdf(dom, '测试', 'splitPages', ',', suc, 2);
pdf.outPutPdfFn('测试');
javascript
复制代码
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>
* breakClassName:自定义分页符类名，默认为break_page,添加改类名的标签被自动分页到下一页
* sucCallback：成功回调函数
* scale：增强图片清晰度 数字也打越清晰
* 调用方式 先 let pdf = new htmlToPdf(ele, 'pdf' ,'itemClass');
* 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 htmlToPdf {
constructor(ele, pdfFileName, splitClassName = "itemClass", breakClassName = "break_page", sucCallback = () => { }, scale = 2) {
this.ele = ele;
this.pdfFileName = pdfFileName;
this.splitClassName = splitClassName;
this.breakClassName = breakClassName;
this.sucCallback = sucCallback;
this.scale = scale;
this.A4_WIDTH = 595;
this.A4_HEIGHT = 842;
this.pageHeight = 0
this.pageNum = 1
};
async getPDF(resolve) {
let 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(this.scale, this.scale) // 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 => {
let contentWidth = canvas.width
let contentHeight = canvas.height
// 一页pdf显示html页面生成的canvas高度;
this.pageHeight = (contentWidth / this.A4_WIDTH) * this.A4_HEIGHT
// 这样写的目的在于保持宽高比例一致 this.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 = 0
// 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 - 10 // -10为了页面有右边距
let 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 < this.pageHeight) { // 在pdf.addImage(pageData, 'JPEG', 左，上，宽度，高度)设置在pdf中显示；
// pdf.addImage(pageData, "JPEG", 5, 0, imgWidth, imgHeight)
pdf.addImage(pageData, 'JPEG', 6, 40, imgWidth - 12, imgHeight - 80);
} else { // 分页
while (leftHeight > 0) {
pdf.addImage(pageData, "JPEG", 6, position + 40, imgWidth - 12, imgHeight - 80)
leftHeight -= this.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 = '';
this.sucCallback()
resolve();
})
};
// 输出pdf
async outPutPdfFn(pdfFileName) {
return new Promise((resolve, reject) => { // 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 target = this.ele;
this.pageHeight = target.scrollWidth / this.A4_WIDTH * this.A4_HEIGHT;
this.ele.style.height = 'initial';
pdfFileName ? this.pdfFileName = pdfFileName : null;
this.pageNum = 1; // pdf页数
this.domEach(this.ele)
// 异步函数，导出成功后处理交互
this.getPDF(resolve, reject);
})
};
domEach(dom) {
let childNodes = dom.childNodes
childNodes.forEach((childDom, index) => {
if (this.hasClass(childDom, this.splitClassName)) {
let node = childDom;
let eleBounding = this.ele.getBoundingClientRect();
let bound = node.getBoundingClientRect();
let offset2Ele = bound.top - eleBounding.top
let currentPage = Math.ceil((bound.bottom - eleBounding.top) / this.pageHeight); // 当前元素应该在哪一页
if (this.pageNum < currentPage) {
this.pageNum++
let divParent = childDom.parentNode; // 获取该div的父节点
let newNode = document.createElement('div');
newNode.className = 'emptyDiv';
newNode.style.background = 'white';
newNode.style.height = (this.pageHeight * (this.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 = childDom.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);
}
}
}
if (this.hasClass(childDom, this.breakClassName)) {
this.pageNum++
console.log('break_page');
let eleBounding = this.ele.getBoundingClientRect();
let bound = childDom.getBoundingClientRect();
let offset2Ele = bound.top - eleBounding.top
// 剩余高度
let alreadyHeight = offset2Ele % this.pageHeight
let remainingHeight = this.pageHeight - alreadyHeight + 20
childDom.style.height = remainingHeight + 'px'
}
if (childDom.childNodes.length) {
this.domEach(childDom)
}
})
}
hasClass(element, cls) {
return (`` + element.className + ``).indexOf(`` + cls + ``) > -1;
}
}
export default htmlToPdf;
