2a:["$","title",null,{"children":"PDF.js MultiPage Previous/Next | Aaron Kyle Dennis | Observable"}] 2f:T81b,pdf_viewer_canvas = { var pdfDoc = null, pageNum = 1, pageRendering = false, pageNumPending = null, scale = 0.8, canvas = document.getElementById(canvas_id), ctx = canvas.getContext('2d'); /** * Get page info from document, resize canvas accordingly, and render page. * @param num Page number. */ function renderPage(num) { pageRendering = true; // Using promise to fetch the page pdfDoc.getPage(num).then(function(page) { var viewport = page.getViewport({scale: scale}); canvas.height = viewport.height; canvas.width = viewport.width; // Render PDF page into canvas context var renderContext = { canvasContext: ctx, viewport: viewport }; var renderTask = page.render(renderContext); // Wait for rendering to finish renderTask.promise.then(function() { pageRendering = false; if (pageNumPending !== null) { // New page rendering is pending renderPage(pageNumPending); pageNumPending = null; } }); }); // Update page counters document.getElementById('page_num').textContent = num; } /** * If another page rendering in progress, waits until the rendering is * finised. Otherwise, executes rendering immediately. */ function queueRenderPage(num) { if (pageRendering) { pageNumPending = num; } else { renderPage(num); } } /** * Displays previous page. */ function onPrevPage() { if (pageNum <= 1) { return; } pageNum--; queueRenderPage(pageNum); } document.getElementById('prev').addEventListener('click', onPrevPage); /** * Displays next page. */ function onNextPage() { if (pageNum >= pdfDoc.numPages) { return; } pageNum++; queueRenderPage(pageNum); } document.getElementById('next').addEventListener('click', onNextPage); /** * Asynchronously downloads PDF. */ pdfjsLib.getDocument(url_canvas).promise.then(function(pdfDoc_) { pdfDoc = pdfDoc_; document.getElementById('page_count').textContent = pdfDoc.numPages; // Initial/first page rendering renderPage(pageNum); }); }30:[] 2d:{"id":"651f939d55e90c1e","slug":"pdf-js-multipage-previous-next-example","title":"PDF.js MultiPage Previous/Next","thumbnail":"5ff947895fc7be1bf2ca8ab4da498a94d8c530daac456b54c172c5549758a9e7","access_level":"public","create_time":"$D2019-05-12T21:12:37.088Z","update_time":"$D2024-12-17T11:50:38.948Z","view_time":null,"first_public_time":"$D2019-12-10T01:18:24.804Z","fork":false,"stars":6,"starred":false,"owner":{"type":"team","id":"8d652a601386fcf4","login":"aaronkyle","name":"Aaron Kyle Dennis","avatar_url":"https://avatars-next.observableusercontent.com/eb6d0b32ccc6c8febbf105ce4d2a938819bcbd1c6a2c108d3a9c01745d3590f2","tier":"starter_2024"},"version":117,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"a7fa3027921865cf","login":"aaronkyle","name":"Aaron Kyle Dennis","avatar_url":"https://avatars-next.observableusercontent.com/eb6d0b32ccc6c8febbf105ce4d2a938819bcbd1c6a2c108d3a9c01745d3590f2","tier":null}],"members":[{"type":"individual","id":"a7fa3027921865cf","login":"aaronkyle","name":"Aaron Kyle Dennis","avatar_url":"https://avatars-next.observableusercontent.com/eb6d0b32ccc6c8febbf105ce4d2a938819bcbd1c6a2c108d3a9c01745d3590f2","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"subscribed":null,"forks":11,"collection":{"id":"63becdb427ae4c93","slug":"learning-by-doing","title":"Learning By Doing","owner":{"id":"8d652a601386fcf4","login":"aaronkyle","name":"Aaron Kyle Dennis"}},"type":"notebook","body":{"title":"PDF.js MultiPage Previous/Next","cells":[{"id":0,"value":"md`# PDF.js MultiPage Previous/Next`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":91,"value":"md`\nFrom [PDF.js | Hello World Walkthrough](https://mozilla.github.io/pdf.js/examples/).\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":67,"value":"md`\nThanks to [Fabian Iwand](https://observablehq.com/@mootari) for [getting this to work](https://observablehq.com/@mootari/hello-pdf-js)!\n\n\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":74,"value":"html`\n

\n \n \n \n Page: / \n

\n\n

\n\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":102,"value":"canvas_id = \"the-canvas\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":15,"value":"$2f","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":81,"value":"// Requires githack.com or a similar proxy for CORS headers.\nurl_canvas = 'https://raw.githubusercontent.com/mozilla/pdf.js/ba2edeae/web/compressed.tracemonkey-pldi-09.pdf'","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":87,"value":"pdfjsLib = {\n const [pdfjs, workerSrc] = await Promise.all([\n require(\"pdfjs-dist@2\"),\n require.resolve(\"pdfjs-dist@2/build/pdf.worker.js\")\n ]);\n pdfjs.GlobalWorkerOptions.workerSrc = workerSrc; \n return pdfjs;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"}],"files":"$W30","stdlib":"1","titling":"auto"}} 2e:"$2d:body" 29:E{"digest":"NEXT_REDIRECT;replace;/@aaronkyle/pdf-js-multipage-previous-next-example;307;"}