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For some reason, we're putting all kind of images *except* JPEG into the `imageCache` in `evaluator.js`.[1] This means that in the PDF file in issue 8380, we'll keep sending the *same* two small images[2] to the main-thread and decoding them over and over. This is obviously hugely inefficient! As can be seen from the discussion in the issue, the performance becomes *extremely* bad if the user has the addon "Adblock Plus" installed. However, even in a clean Firefox profile, the performance isn't that great. This patch not only addresses the performance implications of the "Adblock Plus" addon together with that particular PDF file, but it *also* improves the rendering times considerably for *all* users. Locally, with a clean profile, the rendering times are reduced from `~2000 ms` to `~500 ms` for my setup! Obviously, the general structure of the PDF file and its operator sequence is still hugely inefficient, however I'd say that the performance with this patch is good enough to consider the issue (as it stands) resolved.[3] Fixes 8380. --- [1] Not technically true, since inline images are cached from `parser.js`, but whatever :-) [2] The two JPEG images have dimensions 1x2, respectively 4x2. [3] To make this even more efficient, a new state would have to be added to the `QueueOptimizer`. Given that PDF files this stupid fortunately aren't too common, I'm not convinced that it's worth doing.
PDF.js
PDF.js is a Portable Document Format (PDF) viewer that is built with HTML5.
PDF.js is community-driven and supported by Mozilla Labs. Our goal is to create a general-purpose, web standards-based platform for parsing and rendering PDFs.
Contributing
PDF.js is an open source project and always looking for more contributors. To get involved, visit:
- Issue Reporting Guide
- Code Contribution Guide
- Frequently Asked Questions
- Good Beginner Bugs
- Projects
Feel free to stop by #pdfjs on irc.mozilla.org for questions or guidance.
Getting Started
Online demo
Browser Extensions
Firefox (and Seamonkey)
PDF.js is built into version 19+ of Firefox, however one extension is still available:
-
Development Version - This extension is mainly intended for developers/testers, and it is updated every time new code is merged into the PDF.js codebase. It should be quite stable, but might break from time to time.
-
Please note that the extension is not guaranteed to be compatible with Firefox versions that are older than the current ESR version, see the Release Calendar.
-
The extension should also work in Seamonkey, provided that it is based on a Firefox version as above (see Which version of Firefox does SeaMonkey 2.x correspond with?), but we do not guarantee compatibility.
-
Chrome
- The official extension for Chrome can be installed from the Chrome Web Store. This extension is maintained by @Rob--W.
- Build Your Own - Get the code as explained below and issue
gulp chromium. Then open Chrome, go toTools > Extensionand load the (unpackaged) extension from the directorybuild/chromium.
Getting the Code
To get a local copy of the current code, clone it using git:
$ git clone git://github.com/mozilla/pdf.js.git
$ cd pdf.js
Next, install Node.js via the official package or via nvm. You need to install the gulp package globally (see also gulp's getting started):
$ npm install -g gulp-cli
If everything worked out, install all dependencies for PDF.js:
$ npm install
Finally you need to start a local web server as some browsers do not allow opening PDF files using a file:// URL. Run
$ gulp server
and then you can open
It is also possible to view all test PDF files on the right side by opening
Building PDF.js
In order to bundle all src/ files into two production scripts and build the generic
viewer, run:
$ gulp generic
This will generate pdf.js and pdf.worker.js in the build/generic/build/ directory.
Both scripts are needed but only pdf.js needs to be included since pdf.worker.js will
be loaded by pdf.js. If you want to support more browsers than Firefox you'll also need
to include compatibility.js from build/generic/web/. The PDF.js files are large and
should be minified for production.
Using PDF.js in a web application
To use PDF.js in a web application you can choose to use a pre-built version of the library
or to build it from source. We supply pre-built versions for usage with NPM and Bower under
the pdfjs-dist name. For more information and examples please refer to the
wiki page on this subject.
Learning
You can play with the PDF.js API directly from your browser using the live demos below:
The repository contains a hello world example that you can run locally:
For an introduction to the PDF.js code, check out the presentation by our contributor Julian Viereck:
More learning resources can be found at:
Questions
Check out our FAQs and get answers to common questions:
Talk to us on IRC:
- #pdfjs on irc.mozilla.org
File an issue:
Follow us on twitter: @pdfjs