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123 lines
2.9 KiB
JavaScript
123 lines
2.9 KiB
JavaScript
var pdfDoc = null,
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pageNum = 1,
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pageRendering = false,
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pageNumPending = null,
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scale = 1.2,
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canvas = null,
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ctx = null;
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$(document)
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.ready(
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function() {
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canvas = document.getElementById('the-canvas');
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ctx = canvas.getContext('2d');
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document.getElementById('prev').addEventListener('click', onPrevPage);
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document.getElementById('next').addEventListener('click', onNextPage);
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startPreview(false);
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});
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function translateBaseHtmlPage() {
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//PDF Previewer has prev, next, and Page text on it along with the previewer title
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var pdfPreviewText = $.i18n( "pdfPreviewText" );
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$( '.pdfPreviewText' ).text( pdfPreviewText );
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var prev = $.i18n( "prev" );
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$( '#prev' ).text( prev );
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var next = $.i18n( "next" );
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$( '#next' ).text( next );
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var pageText = $.i18n( "pageText" );
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$( '.pageText' ).text( pageText );
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}
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function writeContent(fileUrl, file, title, authors) {
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addStandardPreviewHeader(file, title, authors);
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// Loaded via <script> tag, create shortcut to access PDF.js exports.
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var pdfjsLib = window['pdfjs-dist/build/pdf'];
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// The workerSrc property shall be specified.
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pdfjsLib.GlobalWorkerOptions.workerSrc = '/dataverse-previewers/previewers/js/pdf.worker.js';
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/**
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* Asynchronously downloads PDF.
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*/
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pdfjsLib.getDocument(fileUrl).promise.then(function(pdfDoc_) {
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pdfDoc = pdfDoc_;
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document.getElementById('page_count').textContent = pdfDoc.numPages;
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// Initial/first page rendering
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renderPage(pageNum);
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});
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}
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/**
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* Get page info from document, resize canvas accordingly, and render page.
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* @param num Page number.
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*/
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function renderPage(num) {
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pageRendering = true;
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// Using promise to fetch the page
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pdfDoc.getPage(num).then(function(page) {
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var viewport = page.getViewport({scale: scale});
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canvas.height = viewport.height;
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canvas.width = viewport.width;
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// Render PDF page into canvas context
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var renderContext = {
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canvasContext: ctx,
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viewport: viewport
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};
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var renderTask = page.render(renderContext);
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// Wait for rendering to finish
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renderTask.promise.then(function() {
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$('.lds-spinner').hide();
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pageRendering = false;
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if (pageNumPending !== null) {
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// New page rendering is pending
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renderPage(pageNumPending);
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pageNumPending = null;
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}
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});
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});
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// Update page counters
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document.getElementById('page_num').textContent = num;
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}
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/**
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* If another page rendering in progress, waits until the rendering is
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* finised. Otherwise, executes rendering immediately.
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*/
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function queueRenderPage(num) {
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if (pageRendering) {
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pageNumPending = num;
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} else {
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renderPage(num);
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}
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}
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/**
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* Displays previous page.
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*/
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function onPrevPage() {
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if (pageNum <= 1) {
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return;
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}
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pageNum--;
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queueRenderPage(pageNum);
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}
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/**
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* Displays next page.
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*/
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function onNextPage() {
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if (pageNum >= pdfDoc.numPages) {
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return;
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}
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pageNum++;
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queueRenderPage(pageNum);
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}
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