On 4/4/2025 3:37 AM, Matthias Weber wrote:
Thanks Hans,
but no, I mean something like this (from the mailing list and Tagged PDF
(2024)):
\setupbackend[format=pdf/ua-2]
\setuptagging[state=start]
\setupstructure[state=start]
\setupexternalfigures[location=default]
\starttext
\startPDFalternativetext
{this is a cow}{\externalfigure[cow]}
\stopPDFalternativetext
\stoptext
in order to provide screen readability (but the above doesn’t work, the PDF
doesn’t have the alternate text).
This one will add an Alt to the element
\externalfigure[cow][label={this is a cow}]
This one will wrap the lot with Alt
\startPDFalternativetext{this is a cow}
\externalfigure[cow]
\stopPDFalternativetext
And what is done with it depends on the viewer.
The background is the following: If I want to use my own texts in class, I have
to (by 2026)
— either not make them available to my students
— or make them accessible
— or move/find another job (a serious alternative indeed)
the middle option should work, assuming you added the right info (lke
this label) but to be honest, even that will nto make a document really
accessible
let's assume that the majority of readers doesn't need this
accessibility ... but some need, then you need to identify what is the
problem and solution and then just make a few more variants of the document
- maybe a black/white version
- replacing images by descriptions, more that just "this is a nice
picture" (which is ok for the checker)
- render is a larger font
etc .. all possible already; context has always been about 'multiple
output from the same source without too much hassle' (keep in mind that
it evolved in educational use)
just using some accessibility checker (and trying to satisfy it) is imo
a cheat on potential readers / users .. tuning a document to an audience
is way better
i'm pretty sure that you have ideas on how documents should look ... and
what students need and it's a pitty that one has to waste time on these
managment-driven issues
Making them accessible means machine readable, which comes with its own
problems I loathe.
indeed; the problem is that like many specific pdf features it is big
business ... so conflicting interests
(there are also software vendors out there who claim that they can make
existing docs accessible .. if so, then why tag in the first place and
not do that runtime; in fact, someday soon these llm's will do the job
anyway; some can parse the pdf stream and deduce already)
(validaiton is tricky anyway: what validated yesterday might not today)
> For me this means that all equatiions need to be somehow machine
readable (I haven’t yet tried whether the tagging from Tagged PDF
(2024)) works for my documents)> and to add a reasonably descriptive
text to the hundreds of images.
that's the least of your problems because we have that; in fact we have
tagging already for ages and actually last year we had a presentation at
BT about formulas being 'spoken' in different languages)
the hundreds ...
\setupexternalfigures
[location=default,
label={this is an image}]
will do as a starter
t be clear: tagging is not the most complicated thing to support (adding
it to context was kind of easy), the main issue is lack of tools (and i
don't have acrobat anyway) and the fact that it is a crappy part of pdf
and not well designed
My lecture notes run typically 100-200 pages and are rich of illustrations and
formulas.
From what I can see the only options are tagged PDFs or epubs with mathml. I
have little experience with either but will be happy to learn. Any suggestions
are most welcome.
tagged pdf is there, currently we're moving from mp bitmap / 3d mode
inti columnset mode but after that we probably will look at some tagging
/ export again (in the perspective of Mikaels lecture notes that we use
for testing); concerning epubs ... exporting actually works quite okay
(also tested with lecture notes) but we want to automate that a bit more
(mathml in browsers is in flux anyway)
a lot of this boils down to 'fighting with the viewers etc' which is a
continuous battle with changes (and the fact that i don't need it also
determines priorities)
and of course we need users to test it
Hans
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Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
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