Epic: `a11y` + `pptx`

[cscheid]

• get minimal reproducible examples of a11y failures
• decide on an automated tool that checks for accessibility violations in the pptx format
• Pandoc's pptx writer is quite constrained; figure out if it's possible if it's possible even in principle to make it emit whatever is required. If the constraint is with Pandoc, then we need an upstream fix first.

Existing issues in the repo:

• TBD

[cscheid]

@srvanderplas Would it be possible for you to seek clarification from your institution on how they plan to check for accessibility in pptx and docx output?

[srvanderplas]

Well, I'm not sure I'd go off of what my university is doing - for one thing, their experts haven't been able to answer my questions on whether I have to be 100% compliant or whether 96% is good enough. To be honest, I think they're focusing on using Ally software via Canvas integration (and thus don't provide tools that check content that isn't integrated with Canvas), and suggesting professors manually check content via Office's Accessibility checker. There's very little effort to ensure that any of this conversion will work "at scale", to the point that most of my department seems likely to just stop providing content online at all.

FWIW, the issue with pdf/pptx/docx is that any file provided online, even if it isn't a webpage, must be accessible. So using a word document or powerpoint file is fine, until you provide it to anyone via the web (a LMS counts, even though it requires authentication, but a direct personal email doesn't, from what I understand). I've been trying to help my colleagues transition to HTML equivalents, since those are easier to check (and generally easier to work with, imo), but for those who are still working with microsoft/windows users, I'm entirely sure that the powerpoint/Word accessibility stuff will be an issue.

Given that pptx and docx are both xml-based formats, it should (at least in theory) be possible to read them in as xml and check for at least the basics of alt-text. I did something like that maybe 10 years ago to pull table content out of word documents -- it wasn't fun but it worked. That said, I'm not finding any pre-existing scripts that will do that job, so I imagine it's probably not that simple, and I have too many meetings today to dig into it more deeply right now.