Implementing form filling and accessibility in the Firefox PDF viewer

PDFJS is fantastic.<p>But PDFJS folks, how can you do such a subpar job at documentation?<p>There is really no documentation available on pdfjs. Or a proper changelog. Like in this article they talk about JS execution in pdfjs. And how they have a solution called quickjs. _no_ documentation whatsoever about how to use it.<p>This has been their documentation for years:<p><a href="https:&#x2F;&#x2F;mozilla.github.io&#x2F;pdf.js&#x2F;api&#x2F;" rel="nofollow">https:&#x2F;&#x2F;mozilla.github.io&#x2F;pdf.js&#x2F;api&#x2F;</a><p>Had I created something as complex and magnificent as pdfjs I would&#x27;ve documented _the hell_ out of it.<p>I get that pdfjs usage in normal web is not their priority and what they care about is the Firefox pdf viewer but I&#x27;m sure they would&#x27;ve had a much better contribution rate had they done better api docs.

Why is it that, a ~decade since MacOS started including forms and markups in their default PDF app (Preview) there still isn&#x27;t a sane PDF editor for Windows? Chrome and Firefox&#x27;s PDF viewers don&#x27;t have editing, Edge has editing and forms but bonkers window management (sometimes PDFs open with Edge but not in an Edge window). Adobe Reader DC still tries to ship with malware, and is license-restricted. What gives?

To this day, I do not understand why it is practically impossible to simply rotate a PDF and <i>save it</i> in its rotated form without downloading some additional PDF application.<p>Edit: On Windows. I envy Preview in MacOS

I&#x27;m glad PDF.js&#x27; development continues. I completely missed that they have abandoned the plan to move to PDFium (<a href="https:&#x2F;&#x2F;wiki.mozilla.org&#x2F;Mortar_Project" rel="nofollow">https:&#x2F;&#x2F;wiki.mozilla.org&#x2F;Mortar_Project</a>).

PDF Forms are tricky. Though I would prefer if more attention given to the native PDF libraries like poppler[1] that drive Okular, Evince, Zathura, and many other PDF viewers. There are long-standing bugs[2] with PDF Forms support, especially with non-English languages[3][4][5].<p>[1] <a href="https:&#x2F;&#x2F;poppler.freedesktop.org&#x2F;" rel="nofollow">https:&#x2F;&#x2F;poppler.freedesktop.org&#x2F;</a><p>[2] <a href="https:&#x2F;&#x2F;gitlab.freedesktop.org&#x2F;poppler&#x2F;poppler&#x2F;-&#x2F;issues?label_name%5B%5D=forms" rel="nofollow">https:&#x2F;&#x2F;gitlab.freedesktop.org&#x2F;poppler&#x2F;poppler&#x2F;-&#x2F;issues?labe...</a><p>[3] <a href="https:&#x2F;&#x2F;gitlab.freedesktop.org&#x2F;poppler&#x2F;poppler&#x2F;-&#x2F;issues&#x2F;463" rel="nofollow">https:&#x2F;&#x2F;gitlab.freedesktop.org&#x2F;poppler&#x2F;poppler&#x2F;-&#x2F;issues&#x2F;463</a><p>[4] <a href="https:&#x2F;&#x2F;gitlab.freedesktop.org&#x2F;poppler&#x2F;poppler&#x2F;-&#x2F;issues&#x2F;230" rel="nofollow">https:&#x2F;&#x2F;gitlab.freedesktop.org&#x2F;poppler&#x2F;poppler&#x2F;-&#x2F;issues&#x2F;230</a><p>[5] <a href="https:&#x2F;&#x2F;gitlab.freedesktop.org&#x2F;poppler&#x2F;poppler&#x2F;-&#x2F;issues&#x2F;364" rel="nofollow">https:&#x2F;&#x2F;gitlab.freedesktop.org&#x2F;poppler&#x2F;poppler&#x2F;-&#x2F;issues&#x2F;364</a>

&gt; Thanks to our Telemetry, we discovered that many forms contain and use embedded JavaScript code (yes, that’s a thing!).<p>There are two disturbing things in that sentence. At least the JavaScript I can see a reason for, it can check whether your input is correct and maybe autofill or things like that, and should of course be sandboxed. The telemetry part is more scary.

I wish the Firefox PDF viewer performed a little better...<p>Lately as I&#x27;ve been working on mapping projects and want to view large PDFs I&#x27;ve found many which need to be saved and opened in Preview.app instead of the browser.<p>This is a great example of a map which views horribly in Firefox (try zooming in) but works great in Preview.app: <a href="https:&#x2F;&#x2F;www.bia.gov&#x2F;sites&#x2F;bia.gov&#x2F;files&#x2F;assets&#x2F;public&#x2F;webteam&#x2F;pdf&#x2F;idc1-028635.pdf" rel="nofollow">https:&#x2F;&#x2F;www.bia.gov&#x2F;sites&#x2F;bia.gov&#x2F;files&#x2F;assets&#x2F;public&#x2F;webtea...</a>

I have a learned aversion to PDF features such as forms. It&#x27;s partly because HTML already has pretty good forms; and partly because of the long history of gross PDF security failures by Adobe.<p>I think a PDF viewer (I prefer &quot;reader&quot;, because that&#x27;s what Adobe called their free product) is for <i>viewing</i> PDFs. The point of PDF, to my mind, was that you got a much higher level of control of typography and design than you could get with HTML. So designers and marketers liked it. I have never bought into interactive PDFs.

Remember when Mozilla management promised that they were going to kill pdf.js (why?) and replace it with the chrome pdf viewer, then wasted a few years not pulling it off? Good times.

The new PDF form rendering is working great for me. Thank you, Firefox! I don&#x27;t love PDF files, but it&#x27;s more convenient for me to deal with them in my favorite browser.

It&#x27;s impressive how slowly progress has been made on the firefox pdf viewer. They can&#x27;t print out pages which aren&#x27;t blurry from the viewer even though they&#x27;ve had 8 years notice: <a href="https:&#x2F;&#x2F;bugzilla.mozilla.org&#x2F;show_bug.cgi?id=811002" rel="nofollow">https:&#x2F;&#x2F;bugzilla.mozilla.org&#x2F;show_bug.cgi?id=811002</a>

It seems to me that with WASM, it&#x27;s easier than ever to have good cross platform and performant implementations for dealing with pdf and many other file formats in a sane way.<p>There is a lot of open source software out there that probably already can be compiled to run in a browser with WASM.

I wonder when Mozilla is going to start to include ads in their pdf renderer.<p>I mean it wouldn&#x27;t really be &quot;ads&quot;, more like suggested extra pages provided by trusted partners...