pdf.js/web/viewer.js

/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- /
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */

'use strict';

var pdfDocument, canvas, pageScale, pageDisplay, pageNum, numPages;
function load(userInput) {
  canvas = document.getElementById('canvas');
  canvas.mozOpaque = true;
  pageNum = ('page' in queryParams()) ? parseInt(queryParams().page) : 1;
  pageScale = ('scale' in queryParams()) ? parseInt(queryParams().scale) : 1.5;
  var fileName = userInput;
  if (!userInput) {
    fileName = queryParams().file || 'compressed.tracemonkey-pldi-09.pdf';
  }
  open(fileName);
}

function queryParams() {
  var qs = window.location.search.substring(1);
  var kvs = qs.split('&');
  var params = { };
  for (var i = 0; i < kvs.length; ++i) {
    var kv = kvs[i].split('=');
    params[unescape(kv[0])] = unescape(kv[1]);
  }
  return params;
}

function open(url) {
  document.title = url;
  var req = new XMLHttpRequest();
  req.open('GET', url);
  req.mozResponseType = req.responseType = 'arraybuffer';
  req.expected = (document.URL.indexOf('file:') == 0) ? 0 : 200;
  req.onreadystatechange = function() {
    if (req.readyState == 4 && req.status == req.expected) {
      var data = (req.mozResponseArrayBuffer || req.mozResponse ||
                  req.responseArrayBuffer || req.response);
      pdfDocument = new PDFDoc(new Stream(data));
      numPages = pdfDocument.numPages;
      document.getElementById('numPages').innerHTML = numPages.toString();
      goToPage(pageNum);
    }
  };
  req.send(null);
}

function gotoPage(num) {
  if (0 <= num && num <= numPages)
    pageNum = num;
  displayPage(pageNum);
}

function displayPage(num) {
  document.getElementById('pageNumber').value = num;

  var t0 = Date.now();

  var page = pdfDocument.getPage(pageNum = num);

  var pdfToCssUnitsCoef = 96.0 / 72.0;
  var pageWidth = (page.mediaBox[2] - page.mediaBox[0]);
  var pageHeight = (page.mediaBox[3] - page.mediaBox[1]);
  canvas.width = pageScale * pageWidth * pdfToCssUnitsCoef;
  canvas.height = pageScale * pageHeight * pdfToCssUnitsCoef;

  var t1 = Date.now();
  var ctx = canvas.getContext('2d');
  ctx.save();
  ctx.fillStyle = 'rgb(255, 255, 255)';
  ctx.fillRect(0, 0, canvas.width, canvas.height);
  ctx.restore();

  page.startRendering(
    ctx,
    function() {
      var infoDisplay = document.getElementById('info');
      var stats = page.stats;
      var t2 = stats.compile, t3 = stats.fonts, t4 = stats.render;
      infoDisplay.innerHTML = 'Time to load/compile/fonts/render: ' +
        (t1 - t0) + '/' + (t2 - t1) + '/' + (t3 - t2) + '/' + (t4 - t3) + ' ms';
  });
}

function nextPage() {
  if (pageNum < pdfDocument.numPages)
    displayPage(++pageNum);
}

function prevPage() {
  if (pageNum > 1)
    displayPage(--pageNum);
}

function goToPage(num) {
  if (0 <= num && num <= numPages)
    displayPage(pageNum = num);
}