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Re: PDF Container tags

for

From: Duff Johnson
Date: Sep 29, 2015 8:41AM


> At least with Adobe Reader, Part, Article, Section, Division, and Document tags are exposed for assistive technology to have access to.

This is also my understanding.

> I do not believe that any AT does anything with this information currently

Sadly, also true. In no small part, I believe, because these structure types are underspecified in ISO 32000-1. Accordingly, there’s no benefit to supporting them, since authoring software and (most) users don’t do anything consistent with them.

> , but that isn’t to say that they couldn’t.

As a practical matter AT developers won’t choose to support <Sect>, <Art>, etc. Since the existing specification of these elements is poor, there’s also no consistent usage “in the field”, so therefore, no reward for an AT developer’s efforts.

In fact, as we see from the comments, knowing that AT just ignores them, people use these grouping elements for convenience in remediation as much (more) than they do for some sort of semantic gain.

PDF 2.0, which is entering the final stages of drafting, loses some Grouping structure elements. <Part> and <Div> are the only grouping elements that remain. They have clear purposes, and are quite distinct. We did add 1 grouping element: <Aside>. All of these are straightforward and should help remediators and software developers alike all get on the same page with grouping concepts.

We also added the <DocumentFragment> concept, which addresses a wide variety of content that quite common in PDF form (but never ever seen in HTML). This is likewise defined in a very usable way in ISO 32000-2, certainly as compared to the grouping element concepts in 32000-1.

In all, I hope (and expect) AT developers (not to mention browser developers) to decide that PDF 2.0 is worth supporting. Nothing will make PDF authoring and remediation software come along faster than if AT vendors choose to adopt PDF 2.0.

PDF/UA-2, also under development, will leverage PDF 2.0.

I hope it doesn’t offend too much if I mention that the PDF Technical Conference next month in San Jose is an excellent place for developers to learn all about the guts of PDF accessibility technology, PDF/UA, PDF 2.0, PDF/UA-2 and a lot more. More infor:

http://www.pdfa.org/2015/06/pdf-technical-conference-2015-program/

Duff.