pdf.js/demo.html at master · getdersim/pdf.js · GitHub

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<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>PDF</title>
    <script type="text/javascript" src="build/generic/build/pdf.js"></script>
  </head>
  <body>
    <h1>PDF.js Previous/Next example</h1>

    <div>
      <button id="prev">Previous</button>
      <button id="next">Next</button>
      &nbsp; &nbsp;
      <span>Page: <span id="page_num"></span> / <span id="page_count"></span></span>
    </div>

    <canvas id="the-canvas"></canvas>


    <script type="text/javascript">
      const BASE_URI = window.location.origin;

      PDFJS.disableWorker = false;
      const url = 'http://localhost:5000/hello.pdf'
      PDFJS.workerSrc = `build/generic/build/pdf.worker.js`;

      var pdfDoc = null,
          pageNum = 1,
          pageRendering = false,
          pageNumPending = null,
          scale = 1,
          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);
          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.
       */
      PDFJS.getDocument(url).then(function(pdfDoc_) {
        pdfDoc = pdfDoc_;
        document.getElementById('page_count').textContent = pdfDoc.numPages;

        // Initial/first page rendering
        renderPage(pageNum);
      })

      window.pageNum = pageNum
      window.next = onNextPage
      window.prev = onPrevPage

    </script>
  </body>
</html>