WebAIM - Web Accessibility In Mind

E-mail List Archives

Thread: PDFlib and Link tags

for

Number of posts in this thread: 3 (In chronological order)

From: Alan Zaitchik
Date: Fri, Oct 01 2021 6:24AM
Subject: PDFlib and Link tags
No previous message | Next message →

I’ve read that the PDFlib product cannot generate Link tags (although it does generate Link Annotations).
Their websites sample pdf file “link_annotations.pdf” has no tags at all, remarkably. (I checked in Acrobat and in PAC3.)
Yet both JAWS and NVDA see the links, can navigate to them and activate them.
Anyone with hands on ecperience using PDFlib to create interactive elements?
Anyone who can explain why the screenreaders seem unfazed by the absence of tags in general and Link tags in particular?
Thanks,
Alan

From: Karen McCall
Date: Fri, Oct 01 2021 6:55AM
Subject: Re: PDFlib and Link tags
← Previous message | Next message →

This is true in PDF created using Acrobat as well. If you open an untagged PDF the "phantom links" are automatically generated. If you tag the document, they will not appear in the Tags Tree and if you try to remediate them, it is almost impossible. They won't even show up when you go to Edit PDF and choose Add or Edit Links from the Link tool.

In the conversion settings for Acrobat you can uncheck the check box to Add Links and that seems to get rid of the problem of the "phantom links" but then you have to add them to the PDF.

I've unchecked this in my instance of Acrobat for when I work on untagged PDF. I then have to check it again if I'm using Acrobat to convert to tagged PDF.

Sometimes AI isn't.

Cheers, Karen

-----Original Message-----
From: WebAIM-Forum < = EMAIL ADDRESS REMOVED = > On Behalf Of Alan Zaitchik
Sent: Friday, October 1, 2021 8:24 AM
To: = EMAIL ADDRESS REMOVED =
Subject: [WebAIM] PDFlib and Link tags

I've read that the PDFlib product cannot generate Link tags (although it does generate Link Annotations).
Their websites sample pdf file "link_annotations.pdf" has no tags at all, remarkably. (I checked in Acrobat and in PAC3.) Yet both JAWS and NVDA see the links, can navigate to them and activate them.
Anyone with hands on ecperience using PDFlib to create interactive elements?
Anyone who can explain why the screenreaders seem unfazed by the absence of tags in general and Link tags in particular?
Thanks,
Alan

From: Duff Johnson
Date: Fri, Oct 01 2021 9:14AM
Subject: Re: PDFlib and Link tags
← Previous message | No next message

> I’ve read that the PDFlib product cannot generate Link tags (although it does generate Link Annotations).

This is incorrect. (NOTE: I do not work for PDFlib; these opinions are my own.)

> Their websites sample pdf file “link_annotations.pdf” has no tags at all, remarkably. (I checked in Acrobat and in PAC3.)
> Yet both JAWS and NVDA see the links, can navigate to them and activate them.

That example file derives from a section in the PDFlib Cookbook pertaining to untagged documents, so this is perfectly normal and expected.

As with other such software, PDFlib is a toolbox which does many things; if you use it to create untagged PDF it will do so.

The company also provides accessible examples in the "PDF/UA” category of the PDFlib Cookbook, including examples with links such as:

image_with_link_pdfua1:
https://www.pdflib.com/pdflib-cookbook/pdfua/image_with_link_pdfua1/ <https://www.pdflib.com/pdflib-cookbook/pdfua/image_with_link_pdfua1/>

starter_pdfua1:
https://www.pdflib.com/pdflib-cookbook/pdfua/starter_pdfua1/ <https://www.pdflib.com/pdflib-cookbook/pdfua/starter_pdfua1/>

table_of_contents_pdfua1:
https://www.pdflib.com/pdflib-cookbook/pdfua/table_of_contents_pdfua1/ <https://www.pdflib.com/pdflib-cookbook/pdfua/table_of_contents_pdfua1/>

> Anyone who can explain why the screenreaders seem unfazed by the absence of tags in general and Link tags in particular?

The links exist in the file whether they are tagged or not. Just as the text is often also (mostly) readable by screen-readers irrespective of tagging, so to the links.

The tags provide structure and semantics that the raw content (text and links) cannot themselves provide.

Duff.