前端pdf.js将pdf转为图片，尤其适合电子发票打印

cqwuliu 2024-06-20 10:33:02 阅读 93

写这个的原因就是打电子发票不方便，这个代码是纯js不需要后端服务直接将两张电子发票的pdf转为两张图片渲染到一张A4纸上面（完全不浪费，发票也不会变大），自动完成打印分页，点击打印即可。亲测可用所有电子发票。

<!DOCTYPE html><html><head><meta charset="utf-8" /><title>PDF文件转图片</title><script type="text/javascript" src="js/jquery-3.6.4.min.js"></script><script type="text/javascript" src="js/2.2.228pdf.min.js"></script><script type="text/javascript" src="js/2.2.228.pdf.worker.min.js"></script><script type="text/javascript" src="js/jszip.js"></script><script type="text/javascript" src="js/FileSaver.js"></script><style type="text/css">button { width: 120px;height: 30px;background: none;border: 1px solid #b1afaf;border-radius: 5px;font-size: 12px;font-weight: 1000;color: #384240;cursor: pointer;outline: none;margin: 0 0.5%}button:hover { background: #ccc;}#container { width: 65%;height: 75%;margin-top: 1%;border-radius: 2px;/*border: 2px solid #a29b9b;*/}.pdfInfos { margin: 0 2%;}</style></head><body><div class="showdata" style="margin-top:1%"> <button id="pdf_tourl">合并多个pdf为一个</button><button id="prevpage">上一页</button><button id="nextpage">下一页</button><button id="exportImg">导出每一张图片</button><button onclick="wind_print()">打印</button><button onclick="choosePdf()">选择多个pdf文件</button><input style="display:none" id='chooseFile' type='file' accept="application/pdf" multiple="multiple"></div><div class="showdata" style="margin-top:1%"><span class="pdfInfos">页码：<span id="currentPages"></span><span id="totalPages"></span></span><span class="pdfInfos">文件名：<span id="fileName"></span></span><span class="pdfInfos">文件大小：<span id="fileSize"></span></span></div><div style="position: relative;"><div id="container"></div><img id="imgloading" style="position: absolute;top: 20%;left: 2%;display:none" src="loading.gif"></div></body><script>$("#pdf_tourl").click(function(){ alert("可以使用PDF Arranger软件");});function wind_print(){ $(".showdata").hide();$("#container").css("width","100%");$("#container").css("height","100%");window.print(); $(".showdata").show(); $("#container").css("width","65%");$("#container").css("height","75%");}var currentPages, totalPages //声明一个当前页码及总页数变量var scale = 2; //设置缩放比例，越大生成图片越清晰$('#chooseFile').change(function() { var pdfFilePath = $('#chooseFile').val();if (pdfFilePath) { //$("#imgloading").css('display', 'block');$("#container").empty(); //清空上一PDF文件展示图currentPages = 1; //重置当前页数totalPages = 0; //重置总页数debuggervar filesdata = $('#chooseFile')[0].files; //jquery获取到文件返回属性的值//文件大小var fileSize=0;for (let i = 0; i < filesdata.length; i++) { fileSize += filesdata[i].size;}var mb;if (fileSize) { mb = fileSize / 1048576;if (mb > 10) { alert("文件大小不能>10M");return;}}if (filesdata.length === 1) { $("#fileName").text(filesdata[0].name);} else { $("#fileName").text(filesdata[0].name + "等 " + filesdata.length + " 个文件");}$("#fileSize").text(mb.toFixed(2) + "Mb");//reader.readAsDataURL(filesdata[0]); //将文件读取为 DataURLfor (let j = 0; j < filesdata.length; j++) { var reader = new FileReader();reader.readAsDataURL(filesdata[j]);reader.onload = function(e) { //文件读取成功完成时触发pdfjsLib.getDocument(this.result).then(function(pdf) { //调用pdf.js获取文件if (pdf) { totalPages = pdf.numPages; //获取pdf文件总页数$("#currentPages").text("1/");$("#totalPages").text(totalPages);//遍历动态创建canvasfor (var i = 1; i <= totalPages; i++) { var canvas = document.createElement('canvas');var cid=j+i;canvas.id = "pageNum" + cid;$("#container").append(canvas);var context = canvas.getContext('2d');renderImg(pdf, i, context);}}});};}}});//渲染生成图片function renderImg(pdfFile, pageNumber, canvasContext) { pdfFile.getPage(pageNumber).then(function(page) { //逐页解析PDFvar viewport = page.getViewport(scale); // 页面缩放比例var newcanvas = canvasContext.canvas;//设置canvas真实宽高newcanvas.width = viewport.width;newcanvas.height = viewport.height;//设置canvas在浏览中宽高newcanvas.style.width = "100%";newcanvas.style.height = "100%";//默认显示第一页，其他页隐藏if (pageNumber != 1) { newcanvas.style.display = "none";}var renderContext = { canvasContext: canvasContext,viewport: viewport};page.render(renderContext); //渲染生成});//$("#imgloading").css('display', 'none');return;};//上一页$("#prevpage").click(function() { if (!currentPages || currentPages <= 1) { return;}nowpage = currentPages;currentPages--;$("#currentPages").text(currentPages + "/");var prevcanvas = document.getElementById("pageNum" + currentPages);var currentcanvas = document.getElementById("pageNum" + nowpage);currentcanvas.style.display = "none";prevcanvas.style.display = "block";})//下一页$("#nextpage").click(function() { if (!currentPages || currentPages >= totalPages) { return;}nowpage = currentPages;currentPages++;$("#currentPages").text(currentPages + "/");var nextcanvas = document.getElementById("pageNum" + currentPages);var currentcanvas = document.getElementById("pageNum" + nowpage);currentcanvas.style.display = "none";nextcanvas.style.display = "block";})//导出图片$("#exportImg").click(function() { if (!$('#chooseFile').val()) { alert('请先上传pdf文件')return false;}//$("#imgloading").css('display', 'block');var zip = new JSZip(); //创建一个JSZip实例var images = zip.folder("images"); //创建一个文件夹用来存放图片//遍历canvas，将其生成图片放进文件夹images中$("canvas").each(function(index, ele) { var canvas = document.getElementById("pageNum" + (index + 1));//将图片放进文件夹images中//参数1为图片名称，参数2为图片数据（格式为base64，需去除base64前缀 data:image/png;base64）images.file("photo-" + (index + 1) + ".png", splitBase64(canvas.toDataURL("image/png", 1.0)), { base64: true});})//打包下载zip.generateAsync({ type: "blob"}).then(function(content) { //saveAs(content, "picture.zip"); //saveAs依赖的js文件是FileSaver.jssaveAs(content, "imgFiles.zip"); //saveAs依赖的js文件是FileSaver.js//$("#imgloading").css('display', 'none');});});//截取base64前缀function splitBase64(dataurl) { var arr = dataurl.split(',')return arr[1]}function choosePdf() { $("#chooseFile").click()}</script></html>

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前端pdf.js将pdf转为图片尤其适合电子发票打印

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