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PDF/UA Quandary 2 - Links inside References in TOC - Does this just cause screenreaders to hear duplicate Links?


From: Philip Kiff
Date: May 29, 2018 10:48AM

PDF/UA Quandary 2: Links inside References in TOC

I think that the correct way of tagging a typical Table of Contents in
PDF/UA is to have each TOCI (Table of Contents Item) tag contain a
Reference tag, and then to have a Link tag nested inside the Reference,
so you end up with something like this:

- [TOCI]
- - [Reference]
- - - [Link]
- - - - LinkObj
- - - - Chapter Title
- - - - Page number

However, in my testing with NVDA, it seems that this causes the word
"Link" to be read twice in a screen reader. The first "Link" word I
guess is the way the screenreader indicates the "Reference" tag, and
then it repeats the word when it encounters the "Link" tag.

When I review the PDF/UA spec, it seems that a TOCI can have a Reference
tag as a child, and the Reference tag can obviously have a Link as a
child, but it doesn't seem like a Link tag is actually permitted as a
child of the TOCI on its own. And if I look at how the TOC is tagged in
the longer reference files provided as part of the Matterhorn reference
suite of PDF/UA compliant documents, they employ the Reference tag with
the Link tag nested in it.

However, in the current state of screen reader software, I don't
understand what value the Reference tag is adding to the document. Do I
really need to identify elements in the Table of Contents as
"References"? If I just remove all the Reference tags and make each TOCI
entry into a single, simple Link tag, then there is no duplication of
the word Link. And the resulting PDF will currently pass the PAC 3
automated checker as well.

Maybe the updated PDF/UA specification will change the list of tags
permitted for use as children of TOCI tags?
Or, again, perhaps I've misunderstood the best practice for tagging here?

I don't like the idea that by following a standard correctly, I'm
actually somehow degrading the user experience.


Philip Kiff
D4K Communications