388 lines
14 KiB
JavaScript
388 lines
14 KiB
JavaScript
/**
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* @license
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*
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* MIT License
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*
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* Copyright (c) 2017 Erik Koopmans
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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/**
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* Generate a PDF from an HTML element or string using html2canvas and jsPDF.
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*
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* @param {Element|string} source The source element or HTML string.
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* @param {Object=} opt An object of optional settings: 'margin', 'filename',
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* 'image' ('type' and 'quality'), and 'html2canvas' / 'jspdf', which are
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* sent as settings to their corresponding functions.
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*/
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var html2pdf = (function(html2canvas, jsPDF) {
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/* ---------- MAIN FUNCTION ---------- */
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var html2pdf = function(source, opt) {
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// Handle input.
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opt = objType(opt) === 'object' ? opt : {};
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var source = html2pdf.parseInput(source, opt);
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// Determine the PDF page size.
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var pageSize = jsPDF.getPageSize(opt.jsPDF);
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pageSize.inner = {
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width: pageSize.width - opt.margin[1] - opt.margin[3],
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height: pageSize.height - opt.margin[0] - opt.margin[2]
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};
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pageSize.inner.ratio = pageSize.inner.height / pageSize.inner.width;
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// Copy the source element into a PDF-styled container div.
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var container = html2pdf.makeContainer(source, pageSize);
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var overlay = container.parentElement;
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// Get the locations of all hyperlinks.
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if (opt.enableLinks) {
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// Find all anchor tags and get the container's bounds for reference.
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opt.links = [];
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var links = container.querySelectorAll('a');
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var containerRect = unitConvert(container.getBoundingClientRect(), pageSize.k);
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// Treat each client rect as a separate link (for text-wrapping).
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Array.prototype.forEach.call(links, function(link) {
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var clientRects = link.getClientRects();
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for (var i=0; i<clientRects.length; i++) {
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var clientRect = unitConvert(clientRects[i], pageSize.k);
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clientRect.left -= containerRect.left;
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clientRect.top -= containerRect.top;
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opt.links.push({ el: link, clientRect: clientRect });
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}
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});
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}
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// Render the canvas and pass the result to makePDF.
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var onRendered = opt.html2canvas.onrendered || function() {};
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opt.html2canvas.onrendered = function(canvas) {
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onRendered(canvas);
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document.body.removeChild(overlay);
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html2pdf.makePDF(canvas, pageSize, opt);
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}
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html2canvas(container, opt.html2canvas);
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};
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html2pdf.parseInput = function(source, opt) {
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// Parse the opt object.
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opt.jsPDF = opt.jsPDF || {};
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opt.html2canvas = opt.html2canvas || {};
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opt.filename = opt.filename && objType(opt.filename) === 'string' ? opt.filename : 'file.pdf';
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opt.enableLinks = opt.hasOwnProperty('enableLinks') ? opt.enableLinks : true;
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opt.image = opt.image || {};
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opt.image.type = opt.image.type || 'jpeg';
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opt.image.quality = opt.image.quality || 0.95;
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// Parse the margin property of the opt object.
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switch (objType(opt.margin)) {
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case 'undefined':
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opt.margin = 0;
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case 'number':
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opt.margin = [opt.margin, opt.margin, opt.margin, opt.margin];
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break;
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case 'array':
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if (opt.margin.length === 2) {
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opt.margin = [opt.margin[0], opt.margin[1], opt.margin[0], opt.margin[1]];
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}
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if (opt.margin.length === 4) {
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break;
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}
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default:
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throw 'Invalid margin array.';
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}
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// Parse the source element/string.
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if (!source) {
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throw 'Missing source element or string.';
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} else if (objType(source) === 'string') {
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source = createElement('div', { innerHTML: source });
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} else if (objType(source) === 'element') {
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source = cloneNode(source, opt.html2canvas.javascriptEnabled);
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} else {
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throw 'Invalid source - please specify an HTML Element or string.';
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}
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// Return the parsed input (opt is modified in-place, no need to return).
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return source;
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};
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html2pdf.makeContainer = function(source, pageSize) {
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// Define the CSS styles for the container and its overlay parent.
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var overlayCSS = {
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position: 'fixed', overflow: 'hidden', zIndex: 1000,
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left: 0, right: 0, bottom: 0, top: 0,
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backgroundColor: 'rgba(0,0,0,0.8)'
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};
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var containerCSS = {
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position: 'absolute', width: pageSize.inner.width + pageSize.unit,
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left: 0, right: 0, top: 0, height: 'auto', margin: 'auto',
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backgroundColor: 'white'
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};
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// Set the overlay to hidden (could be changed in the future to provide a print preview).
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overlayCSS.opacity = 0;
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// Create and attach the elements.
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var overlay = createElement('div', { className: 'html2pdf__overlay', style: overlayCSS });
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var container = createElement('div', { className: 'html2pdf__container', style: containerCSS });
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container.appendChild(source);
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overlay.appendChild(container);
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document.body.appendChild(overlay);
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// Enable page-breaks.
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var pageBreaks = source.querySelectorAll('.html2pdf__page-break');
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var pxPageHeight = pageSize.inner.height * pageSize.k / 72 * 96;
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Array.prototype.forEach.call(pageBreaks, function(el) {
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el.style.display = 'block';
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var clientRect = el.getBoundingClientRect();
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el.style.height = pxPageHeight - (clientRect.top % pxPageHeight) + 'px';
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}, this);
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// Return the container.
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return container;
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};
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html2pdf.makePDF = function(canvas, pageSize, opt) {
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// Calculate the number of pages.
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var ctx = canvas.getContext('2d');
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var pxFullHeight = canvas.height;
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var pxPageHeight = Math.floor(canvas.width * pageSize.inner.ratio);
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var nPages = Math.ceil(pxFullHeight / pxPageHeight);
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// Create a one-page canvas to split up the full image.
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var pageCanvas = document.createElement('canvas');
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var pageCtx = pageCanvas.getContext('2d');
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var pageHeight = pageSize.inner.height;
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pageCanvas.width = canvas.width;
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pageCanvas.height = pxPageHeight;
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// Initialize the PDF.
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var pdf = new jsPDF(opt.jsPDF);
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for (var page=0; page<nPages; page++) {
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// Trim the final page to reduce file size.
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if (page === nPages-1) {
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pageCanvas.height = pxFullHeight % pxPageHeight;
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pageHeight = pageCanvas.height * pageSize.inner.width / pageCanvas.width;
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}
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// Display the page.
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var w = pageCanvas.width;
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var h = pageCanvas.height;
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pageCtx.fillStyle = 'white';
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pageCtx.fillRect(0, 0, w, h);
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pageCtx.drawImage(canvas, 0, page*pxPageHeight, w, h, 0, 0, w, h);
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// Add the page to the PDF.
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if (page) pdf.addPage();
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var imgData = pageCanvas.toDataURL('image/' + opt.image.type, opt.image.quality);
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pdf.addImage(imgData, opt.image.type, opt.margin[1], opt.margin[0],
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pageSize.inner.width, pageHeight);
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// Add hyperlinks.
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if (opt.enableLinks) {
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var pageTop = page * pageSize.inner.height;
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opt.links.forEach(function(link) {
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if (link.clientRect.top > pageTop && link.clientRect.top < pageTop + pageSize.inner.height) {
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var left = opt.margin[1] + link.clientRect.left;
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var top = opt.margin[0] + link.clientRect.top - pageTop;
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pdf.link(left, top, link.clientRect.width, link.clientRect.height, { url: link.el.href });
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}
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});
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}
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}
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// Finish the PDF.
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pdf.save( opt.filename );
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}
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/* ---------- UTILS ---------- */
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// Determine the type of a variable/object.
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var objType = function(obj) {
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if (typeof obj === 'undefined') return 'undefined';
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else if (typeof obj === 'string' || obj instanceof String) return 'string';
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else if (typeof obj === 'number' || obj instanceof Number) return 'number';
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else if (!!obj && obj.constructor === Array) return 'array';
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else if (obj && obj.nodeType === 1) return 'element';
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else if (typeof obj === 'object') return 'object';
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else return 'unknown';
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};
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// Create an HTML element with optional className, innerHTML, and style.
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var createElement = function(tagName, opt) {
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var el = document.createElement(tagName);
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if (opt.className) el.className = opt.className;
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if (opt.innerHTML) {
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el.innerHTML = opt.innerHTML;
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var scripts = el.getElementsByTagName('script');
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for (var i = scripts.length; i-- > 0; null) {
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scripts[i].parentNode.removeChild(scripts[i]);
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}
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}
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for (var key in opt.style) {
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el.style[key] = opt.style[key];
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}
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return el;
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};
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// Deep-clone a node and preserve contents/properties.
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var cloneNode = function(node, javascriptEnabled) {
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// Recursively clone the node.
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var clone = node.nodeType === 3 ? document.createTextNode(node.nodeValue) : node.cloneNode(false);
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for (var child = node.firstChild; child; child = child.nextSibling) {
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if (javascriptEnabled === true || child.nodeType !== 1 || child.nodeName !== 'SCRIPT') {
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clone.appendChild(cloneNode(child, javascriptEnabled));
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}
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}
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if (node.nodeType === 1) {
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// Preserve contents/properties of special nodes.
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if (node.nodeName === 'CANVAS') {
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clone.width = node.width;
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clone.height = node.height;
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clone.getContext('2d').drawImage(node, 0, 0);
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} else if (node.nodeName === 'TEXTAREA' || node.nodeName === 'SELECT') {
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clone.value = node.value;
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}
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// Preserve the node's scroll position when it loads.
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clone.addEventListener('load', function() {
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clone.scrollTop = node.scrollTop;
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clone.scrollLeft = node.scrollLeft;
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}, true);
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}
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// Return the cloned node.
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return clone;
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}
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// Convert units using the conversion value 'k' from jsPDF.
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var unitConvert = function(obj, k) {
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var newObj = {};
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for (var key in obj) {
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newObj[key] = obj[key] * 72 / 96 / k;
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}
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return newObj;
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};
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// Get dimensions of a PDF page, as determined by jsPDF.
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jsPDF.getPageSize = function(orientation, unit, format) {
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// Decode options object
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if (typeof orientation === 'object') {
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var options = orientation;
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orientation = options.orientation;
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unit = options.unit || unit;
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format = options.format || format;
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}
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// Default options
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unit = unit || 'mm';
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format = format || 'a4';
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orientation = ('' + (orientation || 'P')).toLowerCase();
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var format_as_string = ('' + format).toLowerCase();
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// Size in pt of various paper formats
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pageFormats = {
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'a0' : [2383.94, 3370.39], 'a1' : [1683.78, 2383.94],
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'a2' : [1190.55, 1683.78], 'a3' : [ 841.89, 1190.55],
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'a4' : [ 595.28, 841.89], 'a5' : [ 419.53, 595.28],
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'a6' : [ 297.64, 419.53], 'a7' : [ 209.76, 297.64],
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'a8' : [ 147.40, 209.76], 'a9' : [ 104.88, 147.40],
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'a10' : [ 73.70, 104.88], 'b0' : [2834.65, 4008.19],
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'b1' : [2004.09, 2834.65], 'b2' : [1417.32, 2004.09],
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'b3' : [1000.63, 1417.32], 'b4' : [ 708.66, 1000.63],
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'b5' : [ 498.90, 708.66], 'b6' : [ 354.33, 498.90],
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'b7' : [ 249.45, 354.33], 'b8' : [ 175.75, 249.45],
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'b9' : [ 124.72, 175.75], 'b10' : [ 87.87, 124.72],
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'c0' : [2599.37, 3676.54], 'c1' : [1836.85, 2599.37],
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'c2' : [1298.27, 1836.85], 'c3' : [ 918.43, 1298.27],
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'c4' : [ 649.13, 918.43], 'c5' : [ 459.21, 649.13],
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'c6' : [ 323.15, 459.21], 'c7' : [ 229.61, 323.15],
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'c8' : [ 161.57, 229.61], 'c9' : [ 113.39, 161.57],
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'c10' : [ 79.37, 113.39], 'dl' : [ 311.81, 623.62],
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'letter' : [612, 792],
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'government-letter' : [576, 756],
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'legal' : [612, 1008],
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'junior-legal' : [576, 360],
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'ledger' : [1224, 792],
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'tabloid' : [792, 1224],
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'credit-card' : [153, 243]
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};
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// Unit conversion
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switch (unit) {
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case 'pt': k = 1; break;
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case 'mm': k = 72 / 25.4; break;
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case 'cm': k = 72 / 2.54; break;
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case 'in': k = 72; break;
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case 'px': k = 72 / 96; break;
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case 'pc': k = 12; break;
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case 'em': k = 12; break;
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case 'ex': k = 6; break;
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default:
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throw ('Invalid unit: ' + unit);
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}
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// Dimensions are stored as user units and converted to points on output
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if (pageFormats.hasOwnProperty(format_as_string)) {
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pageHeight = pageFormats[format_as_string][1] / k;
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pageWidth = pageFormats[format_as_string][0] / k;
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} else {
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try {
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pageHeight = format[1];
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pageWidth = format[0];
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} catch (err) {
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throw new Error('Invalid format: ' + format);
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}
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}
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// Handle page orientation
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if (orientation === 'p' || orientation === 'portrait') {
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orientation = 'p';
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if (pageWidth > pageHeight) {
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tmp = pageWidth;
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pageWidth = pageHeight;
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pageHeight = tmp;
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}
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} else if (orientation === 'l' || orientation === 'landscape') {
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orientation = 'l';
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if (pageHeight > pageWidth) {
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tmp = pageWidth;
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pageWidth = pageHeight;
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pageHeight = tmp;
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}
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} else {
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throw('Invalid orientation: ' + orientation);
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}
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// Return information (k is the unit conversion ratio from pts)
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var info = { 'width': pageWidth, 'height': pageHeight, 'unit': unit, 'k': k };
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return info;
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};
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// Expose the html2pdf function.
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return html2pdf;
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}(html2canvas, jsPDF));
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