Am Tue, 29 Apr 2025 13:13:39 -0400 schrieb Matthias Weber:
> Dear All,
>
> I am starting a new thread as requested.
>
> I can confirm that
>
>
>>
>> the following should work with current latest (from yesterday,
>> LuaMetaTeX 2.11.07 20250427 + ConTeXt LMTX 2025.04.28 14:29):
>>
>> \enabledirectives [backend.usetags=testing]
>> \setuptagging[state=start]
>> \setupstructure[state=start]
>> \setupbackend
>> [format=PDF/A-3a]
>> \setupbackend[format=pdf/ua-1]
>> \setupexternalfigures[location=default]
>> \starttext
>> \externalfigure[hacker][label={this is an image}]
>>
>> \startparagraph
>> a
>> \stopparagraph
>> \stoptext
>
> produces a PDF that passes the accessibility check in the current Adobe
> Acrobat. In particular, it passes the alternate text checks.
> Hovering over the image shows the alternate text in Acrobat.
> However, VoiceOver (on the Mac) does not read the alternate text;
The pdf produced by context maps every structure to NonStruct, that
means there is no tagging structure, it only fools the accessibility
check. You can and should not claim that this an ua-1 file. You can
check the structure by uploading your pdf to
https://texlive.net/showtags, that will produce an xml from the
structure.
I don't know if the missing structure is the reason that VoiceOver
fails, as I'm on windows, but you could try with a LaTeX document.
Go to https://texlive.net/ngpdf and compile there this example:
\DocumentMetadata{tagging=on}
\documentclass{article}
\usepackage{graphicx}
\begin{document}
some text
\includegraphics[alt=an image with a duck]{example-image-duck}
\end{document}
After the compilation you can download the pdf and compare the
reading.
I made a fast check with Adobe + NVDA: it reads the actual text of
your image, but it doesn't announce that there is graphic. So for
the context file you get simply
this is an image
while the LaTeX file is read as
graphic an image with a duck.
--
Ulrike Fischer
http://www.troubleshooting-tex.de/
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