# Embedded PDF Viewer based on pdf.js

This directory contains an official pdf.js release version, distributed at: https://github.com/mozilla/pdf.js

## Update process
1. Delete existing files except epiphany-pdfjs-changes.patch, pdfjs_generate_resource.py, and README.epiphany.md.
2. Grab a new official release (*-dist.zip) distributed at github and extract everything into this directory.
3. Delete precompiled .map files (viewer.js.map, pdf.js.map, pdf.worker.js.map, pdf.sandbox.js.map).
4. Manually merge changes from epiphany-pdfjs-changes.patch into web/viewer.[html/js/css].
5. Recreate epiphany-pdfjs-changes.patch.
6. Recreate the resource xml file with `./pdfjs_generate_resource.py`

## Modifications to viewer.html
1. In order to circumvent CORS the pdf is downloaded and then embedded into the viewer.html file. Therefore the head has an
extra attribute 'pdf_data="%s' which will be replace by Epiphany. Extracting this data is done in viewer.js.

2. Futhermore 'pdf_name="%s"' is supplied to set the download file name.

3. '<base href="ephy-resource:///org/gnome/epiphany/pdfjs/web/">' has been added to the head section.

## Modifications to viewer.js

function webViewerInitialized() has been changed:

1. Set file to ''

2. Replace the end of the function with:

  var file_name = document.head.getAttribute('pdf_name')
  var raw = atob(document.head.getAttribute('pdf_data'));
  var raw_length = raw.length;
  var array = new Uint8Array(new ArrayBuffer(raw_length));

  for(var i = 0; i < raw_length; i++) {
    array[i] = raw.charCodeAt(i);
  }
    
  try {
      PDFViewerApplication.open(array);
      PDFViewerApplication.setTitleUsingUrl(file_name);
  } catch (reason) {
    PDFViewerApplication.l10n.get('loading_error', null, 'An error occurred while loading the PDF.').then(function (msg) {
      PDFViewerApplication.error(msg, reason);
    });
  }

3. Disable history modification, otherwise base url is set as main url and translation won't work.

In _pushOrReplaceState early return before the window.history.xxx changes

4. Hide secondaryViewBookmark and viewBookmark
Switch id's secondaryViewBookmark and viewBookmark from visibleSmallView and hiddenSmallView to hidden.

## Modifications to viewer.css

Here are two small changes for webkit specific layout:

1. Adding:
-webkit-appearance: none; to .dropdownToolbarButton > select {

2. Adding:
.toolbarField.pageNumber { blocks in the css


## Patch with changes for Epiphany

For easier updating to a newer version there is a patch file `epiphany-pdfjs-changes.patch` containing the necessary changes to the viewer files.

## Note
Do not add map files to this bundle (webinspector will complain about it), but they are not needed here and would increase our storage size otherwise.

# Documentation created by Jan-Michael Brummer <jan.brummer@tabos.org>