[EE84M3i]

Isn't the whole point of PDFs that they (mostly) don't change? They represent content as laid out on a page.

So, IMO this is neat if it's new tech for reading PDFs and extracting data from them (and maybe leveraging current under-used features to store more machine-readable information), but bad if it's about introducing even more complexity into the PDF documents.

Perhaps 10 years from now we will have responsive PDFs, but I feel sorry for whatever damned soul is going to have to expand hard-coded limits in order to fit the new PDF specification text into a single PDF document.

[modernerd]

This is more like a readability mode than a responsive website.

It's a button you click to automatically make a fixed-layout PDF fluid and easier to read on mobile.

You'd still author the document the same way without considering multiple device sizes. When the PDF needs to be reproduced faithfully (printing) it would still appear as the creator intended.

[ISL]

For many, the point of a PDF is that it appears the same way in all contexts. For device-dependent rendering, we have HTML.

[tshaddox]

It's not crazy to have a device-independent presentational document that also contains enough data to enable some device-dependent rendering of its text and media contents.

[citizenkeen]

I read a boatload of 2 column PDFs on my phone. Liquid Mode has been on PDF Reader on Android for... it feels like a year now? And it's fantastic. Without it I have to constantly pinch and zoom and swipe to the upper right to start a new column, etc.

I hate PDFs, but if I want to read a document I've stored in print fidelity from the 80s on my phone, Liquid is rock solid.

[yeellow]

Which android pdf reader has it?

[Ayesh]

Not OP. Xiaomi MIUI bundles WPS office, which has a "mobile view" for PDFs. It's far from perfect, but it can single-column some multi-column PDFs. Some PDFs, like restaurant PDFs are downright butchered though.

[virgilp]

I would guess Adobe's? Or otherwise it's not "Liquid Mode" but a similar feature...

[yeellow]

According to the article Adobe reader for Android got this feature recently. I tried it and I am disappointed. Maybe OP was talking about reflow mode that indeed was accessible in many pdf readers, but for technical papers (math) it was useless.

[coldtea]

That would be the case if a PDF was solely used for print.

In the digital realm though, a PDF should also be accessible to screenreaders for the blind, people with sight problems (increased fonts, contrast), dyslexia, etc. Those already require alternative representations.

And of course nothing bad about having the best of both worlds! A format that is pixel perfect when you want it too, and adaptable for easier reading when you don't.

[ebg13]

> For device-dependent rendering, we have HTML.

It does not sound like the goal is device-dependent rendering, though. This is exactly parallel to Reader Mode, which is a temporary user toggle. The goal of PDF is still to produce documents that mirror print-ready layouts, something that HTML has never really accomplished. Whether you want to consume the documents that way will now be up to you.

[unicornporn]

> For device-dependent rendering, we have HTML.

Say that to those who create PDF files for things that should be web pages. That behavior is not going to stop anytime soon.

[snowwrestler]

This is kind of funny to me since what is now the iOS Core Graphics framework started out life as a PDF rendering engine.

[emteycz]

Sadly no one really publishes books as HTML.

[svachalek]

Not sure if this is sarcastic but FYI:

https://en.wikipedia.org/wiki/Comparison_of_e-book_formats

(spoiler, most of them are HTML/CSS)

[emteycz]

Most books I saw were epub and pdf. They say epub is some XML, ok. But I don't see how the number of existing HTML based formats is relevant

[barumi]

> They say epub is some XML, ok.

Epub is HTML and CSS bundled in a zip file following a specific directory tree layout and containing a few metadata files.

Epub 3 is HTML5.

Open LibreOffice, create a doc, save it as Epub, and unzip the file. See for yourself.

[kevincox]

Aren't the most popular ebook formats based on HTML?

[munk-a]

They do, they just don't end up being called books. I'm a big fan of http://learnyouahaskell.com/

[matt_f]

That's awesome stuff there

[mattnewton]

Lots of books (in major digital bookstores like ibooks) are published as "epub" which is basically html.

[scythe]

>It's a button you click to automatically make a fixed-layout PDF fluid and easier to read on mobile.

But this of course reminds us of the miserable UX we have come to accept from the "mobile web". In the beginning, mobile websites didn't exist, and you just zoomed. Now, it's practically impossible to view the desktop website from a phone at some URLs without jailbreaking your device (if it's iOS). The net effect has been a severe degradation of usability in the worst cases for a small improvement in aesthetics and speed in the best.

I truly hope that PDFs do not meet the same fate, and remain readable on mobile in the correct layout, with no in-document markers that force my iPhone to display it wrong. While that apparently hasn't been proposed here, I don't like even the risk of it being proposed.

[lotsofpulp]

The best restaurant website experiences I have are when the whole website is just a pdf of the menu with contact info.

Maybe put a link on the pdf for online ordering or finding locations, but I have no idea why the home page should be anything but a menu.

[brokenmachine]

I like to see pictures of the room/view as well.

[saint-loup]

About "responsive PDFs": there's already a "reflow" feature in Acrobat Reader. It's limited but kinda works on clean PDFs. I don't know to what extent it's a explicit possibility of the PDF standard.

https://helpx.adobe.com/acrobat/using/reading-pdfs-reflow-ac...