Matthias Valvekens

Mathematician/Software engineer/PDF expert/FOSS dev

Opinions are my own.

[Dan Lorenc @lorenc_dan]

Oh wow, finally!

ed25519 is an approved NIST digital signature standard: https://t.co/qUbdNB0o8p

[Matthias Valvekens @MatthiasVal]

People are already implementing ISO/TS 32001 and 32002 out there!

(...and it's not just me, I promise!)

[PDF Association @PDFAssociation]

Read an overview of new extensions and clarifications to PDF 2.0 in support of advanced #cryptography. #AES #FIPS

https://t.co/2vJN1d1lKh

[Daniel Litt @littmath]

when you know what “statistically significant” means

[Matthias Valvekens @MatthiasVal]

@wtfpdf I think/hope we'll see some improvement once LaTeX ships with easy-to-use tagging support---and the academic publishing world gets around to updating their stuff... 🤞

[Matthias Valvekens @MatthiasVal]

@wtfpdf The LaTeX project is working on this exact problem: making it easier to produce well-tagged output from TeX with minimal user intervention.

[Matthias Valvekens @MatthiasVal]

@Oil_vampire @teleoqoelet @Atypical_Andy @harryhhutch For some applications, sure. But not always: there are lots of companies that make money by having industrial appliances shut down _voluntarily_ when power is scarce: https://t.co/QXBMTmhGQg

These days, many grid operators have a programme like this.

[Matthias Valvekens @MatthiasVal]

@petervwyatt @wtfpdf Follow-up question: what would be the right colour profile for artwork on T-shirts? 🙈

[Matthias Valvekens @MatthiasVal]

🥁🥁 You can now use EdDSA in #pdf signatures!

...well, at least we have an #ISO spec for it now. Quick write-up (+DIY demo) here: https://t.co/ELPtRYuwiH

[Matthias Valvekens @MatthiasVal]

@MyMilkedEek ESTA?

Anyway, as we all know, the famous list of misconceptions programmers hold about names applies _extra_ to US gov't contractors. 🙈

[Matthias Valvekens @MatthiasVal]

@_plinth_ @MyMilkedEek By the way, this one is even more fun: 3 0 obj 3 0 R endobj ;)

[Matthias Valvekens @MatthiasVal]

@_plinth_ @MyMilkedEek Sure, I should've been more nuanced w.r.t. the infinite loop <> stack overflow issue, but the effect is pretty much the same: you'd need to keep track of some state while traversing if you want to do this safely.

[Matthias Valvekens @MatthiasVal]

@_plinth_ @MyMilkedEek Notable exception: "naked" indirect objects are forbidden in object streams, but that's it.

[Matthias Valvekens @MatthiasVal]

@_plinth_ @MyMilkedEek Yeah, this issue is actually the subject of some current debate in the PDF standards community, actually. Blindly dereferencing recursively is problematic (if only because loops would blow up the stack), but there's indeed no clear file format requirement banning the practice...

[Matthias Valvekens @MatthiasVal]

While I use a MacBook when travelling, I've used a Linux box as my main dev machine for most of the past decade :). You're right that the "PDF on the Linux desktop" experience is lagging behind, though.

TL;DR: I use arch btw

[Matthias Valvekens @MatthiasVal]

@jacko_os @wtfpdf Don't worry, that's a natural reaction 😁. Over-reliance on 2-byte wide encodings was a historical mistake (see also: the Windows API and Java).

It made sense when there were <65536 codepoints, but that stopped being true decades ago, so... UTF-16 should really be obsolete. 🤷‍♂️

[Matthias Valvekens @MatthiasVal]

@wtfpdf @jacko_os As for PDF 1.2: this encoding scheme is described in section 4.4, although it's not yet called "UTF-16BE" in there (just "Unicode"), presumably because the whole "character set vs. encoding" debate was still ongoing at the time.

But, TL;DR: Yep, this is also valid in PDF 1.2

[Matthias Valvekens @MatthiasVal]

@jacko_os @wtfpdf Yep, this is a perfectly valid PDF string. As a data type, PDF strings represent byte strings first and foremost, and this one maps to 0xFE 0xFF 0x00 0x48 0x00 0x69.

[Michael Demey @MyMilkedEek]

Friends don't let friends print and sign. #truefriendship #pdf