2e:null 2f:["$","title",null,{"children":"PDF.js MultiPage Previous/Next | grasshoff | Observable"}] 34:T803,{ var pdfDoc = null, pageNum = 1, pageRendering = false, pageNumPending = null, scale = 0.8, canvas = document.getElementById('the-canvas'), 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).promise.then(function(pdfDoc_) { pdfDoc = pdfDoc_; document.getElementById('page_count').textContent = pdfDoc.numPages; // Initial/first page rendering renderPage(pageNum); }); }35:[] 32:{"id":"61ce6835e32518c9","slug":"pdf-js-multipage-previous-next","title":"PDF.js MultiPage Previous/Next","thumbnail":null,"access_level":"public","create_time":"$D2020-10-06T14:26:10.728Z","update_time":"$D2020-10-06T14:46:31.817Z","view_time":null,"first_public_time":"$D2020-10-06T14:47:39.138Z","has_unpublished_edits":null,"fork":{"id":"651f939d55e90c1e","slug":"pdf-js-multipage-previous-next-example","title":"PDF.js MultiPage Previous/Next","owner":{"id":"8d652a601386fcf4","login":"aaronkyle","name":"Aaron Kyle Dennis"}},"stars":1,"starred":false,"owner":{"type":"team","id":"71dfe5d9a0c03897","login":"grasshoff","name":"","avatar_url":"https://avatars-next.observableusercontent.com/1aad9c751a6c4a4e491271eef020dc049786677f9f998dd9a9ff01255af7946f","tier":"starter_2024"},"version":101,"publish_version":101,"role":null,"authored":false,"authors":[{"type":"individual","id":"57a2483c6252f8ec","login":"grasshoff","name":"","avatar_url":"https://avatars-next.observableusercontent.com/1aad9c751a6c4a4e491271eef020dc049786677f9f998dd9a9ff01255af7946f","tier":null}],"members":[{"type":"individual","id":"57a2483c6252f8ec","login":"grasshoff","name":"","avatar_url":"https://avatars-next.observableusercontent.com/1aad9c751a6c4a4e491271eef020dc049786677f9f998dd9a9ff01255af7946f","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"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","output":"$undefined","database":"$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","output":"$undefined","database":"$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","output":"$undefined","database":"$undefined"},{"id":74,"value":"html`\n\n\n

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

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