Thanks, Pablo (and everybody else reading this),
I should have put my question differently. When using the math.textblobs
tracker, this code:
\enabledirectives [backend.usetags=testing]
\setuptagging[state=start]
\setupstructure[state=start]
\setupbackend
[format=PDF/A-3a]
\setupbackend[format=pdf/ua-1]
\setupexternalfigures[location=default]
\setupnote[mathnote][location=page]
\enabletrackers[math.textblobs]
\starttext
$1+1=3$
\stoptext
will put all math into what I think Hans calls “serialized math" into a
footnote (please correct me if I'm wrong). Are there other ways to access that
serialized math?
One approach to making math and images accessible would be to use modes to
replace all figures with their alt-texts and all math with their serialized
math, so that the output of ConTeXt would be a PDF where all elements that are
difficult to navigate are replaced with plain text. This is, of course, only
one of many possible approaches. This would circumvent all tagging issues for
the time being.
I am just trying to (in this order)
— Make my lecture notes useful for vision-impaired readers
— Achieve this as easily and cleanly as possible
— Eventually reach some form of compliance with legal requirements
Thanks again,
Matthias
> On Jun 18, 2025, at 1:23 PM, Pablo Rodriguez via ntg-context
> <ntg-context@ntg.nl> wrote:
>
> On 6/15/25 18:03, Matthias Weber wrote:
>> [...]
>> I can do this manually, but my figures contain quite a bit of math,
>> and it would be nice if alternate text for math is provided
>> consistently throughout the document.
>
> Dear Matthias,
>
> my background is in humanities. This is why I see that tagging is
> lacking language (for mixed-languages documents 😅).
>
> I wonder whether it would make sense to replace your label with:
>
> {\externalfigure[cow][label={A cow, contemplating}]
> {\blank[-3st]\color[white]{$e^{\pi i}+1=0$}}} % path
>
> Of course, full transparent text would make sense with other backgrounds
> (either from the page or the image itself).
>
> As for tagging, reading the info with https://ngpdf.com alternative text
> seems fine to me (but I cannot speak for software readers).
>
> Just in case it may help,
>
> Pablo
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