PDF.js Previous/Next example

by prateekbansal07

HTML

<script src="//mozilla.github.io/pdf.js/build/pdf.js"></script>

<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>

CSS

#the-canvas {
  border: 1px solid black;
  direction: ltr;
}

JavaScript

// If absolute URL from the remote server is provided, configure the CORS
// header on that server.
var url = 'https://raw.githubusercontent.com/mozilla/pdf.js/ba2edeae/web/compressed.tracemonkey-pldi-09.pdf';

// Loaded via <script> tag, create shortcut to access PDF.js exports.
var pdfjsLib = window['pdfjs-dist/build/pdf'];

// The workerSrc property shall be specified.
pdfjsLib.GlobalWorkerOptions.workerSrc = '//mozilla.github.io/pdf.js/build/pdf.worker.js';

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.
 */
 var searchText = "Trace";
function searchPage(pageNumber) {
var doc =pdfDoc;
  return doc.getPage(pageNumber).then(function (page) {
    return page.getTextContent();
  }).then(function (content) {
    // Search combined text content using regular expression
    var text = content.items.map(function (i) { return i.str; }).join('');
    var re = new RegExp("(.{0,20})" + searchText + "(.{0,20})", "gi"), m;
    var lines = [];
    while (m = re.exec(text)) {
      var line = (m[1] ? "..." : "") + m[0] + (m[2] ? "..." : "");
      lines.push(line);
    }
    return {page: pageNumber, items: lines};
  });
}
 
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...