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Re: Z-Order and Tag Order Need to Match?

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From: Paul Rayius
Date: May 27, 2020 4:36PM

Hi Michael,
As I just replied to another post on this thread, As per ISO 32000, one of the intents of PDF is that the "accessible layer" and the visual layer are independent of each other. (Apparently there are multiple strings going on at the same time!)
Among the benefits of this is that it's possible to add attributes (like Alternative text) and to change the reading order in the Tags without effecting the physical appearance of the document. Meanwhile, moving things around in the Content can (and often does) change how the document looks.

It was a design decision by our developers to make CommonLook so that the Content panel isn't changed when remediating a PDF. In fact, in a (much) older version of CommonLook PDF, we used to have the "merged view" which did change the order of things in the Tags and the Content at the same time but people had to be really careful or else they could change how the document looked visually. We did away with that about 5 years ago.

I hope that explanation helps.

Paul Rayius
Director of Training
CommonLook

-----Original Message-----
From: WebAIM-Forum < <EMAIL REMOVED> > On Behalf Of Vaughn, Michael
Sent: Wednesday, May 27, 2020 5:22 PM
To: WebAIM Discussion List < <EMAIL REMOVED> >
Subject: Re: [WebAIM] Z-Order and Tag Order Need to Match?

Hi Paul,

One of the assistive technologies that relies on the Content order rather than the tags is the PDF reader in Read&Write from TextHelp, which is a popular tool used in education settings.

I'm a CommonLook customer, and I wonder if that tool includes any feature to correct the Content order to match the tag order?

Thanks

_____
Michael Vaughn (he/him/his)
Associate Director of Digital Accessibility Yale University, Information Technology Services
25 Science Park, 542 | 203.432.9620
accessibility.yale.edu <http://accessibility.yale.edu/>;


On 5/27/20, 2:36 PM, "WebAIM-Forum on behalf of Paul Rayius" < <EMAIL REMOVED> on behalf of <EMAIL REMOVED> > wrote:

Hi Ilana,
There's often a lot of question/ debate about this. When it comes to PDF standards (both ISO 32000 and PDF/UA, as well as WCAG 2.0 and 2.1) they're all quite clear that the reading order in a PDF shall be determined by the order of the tags. (To be more clear, WCAG doesn't specify the reading order "rules" for PDF but does provide some guidance in the WCAG Techniques.)

The confusion comes into play because some assistive technologies don't actually follow the standards and so they'll read content from "other areas" in a PDF - for example from the Content and or "Z-Order" pane in Acrobat. (The "Z-Order" pane is the one labeled "Order" but many people call it the "Z-Order" because of the "Z" in the icon.)

The problem, however, is that as accessible document creators and/or remediators, we can't possibly be called on to remediate according to how a particular processor or AT will handle a PDF. In fact, to that point, one of the great things about WCAG is that it's intended for accessibility while being technology independent. Personally, I think it's time for PDF processors and AT developers to be held accountable and that their products should adhere to the standards that are not only available but also achievable. But, that's my soapbox.

I hope this helps to clarify, though, that the reading order in a PDF is to be determined by the order of the Tags and not the "Z-Order."

Best,
Paul

Paul Rayius
Director of Training
CommonLook

-----Original Message-----
From: WebAIM-Forum < <EMAIL REMOVED> > On Behalf Of Ilana Gordon
Sent: Wednesday, May 27, 2020 12:56 PM
To: WebAIM Discussion List < <EMAIL REMOVED> >
Subject: Re: [WebAIM] Z-Order and Tag Order Need to Match?

I wish they had a checklist. They are a moving target and keep asking for things that seem over the top and in additional to the HHS checklist.

Ilana

On Wed, May 27, 2020 at 12:46 PM Ryan E. Benson < <EMAIL REMOVED> >
wrote:

> Are you talking to the agency 508 Coordinator directly, or somebody else?
> Does the agency have a checklist?
>
> --
> Ryan E. Benson
>
>
> On Wed, May 27, 2020 at 12:23 PM Ilana Gordon
> < <EMAIL REMOVED> >
> wrote:
>
> > I should clarify that this is specifically for PDFs. And some
> > government employee says it's a requirements.
> >
> > Ilana
> >
> > On Wed, May 27, 2020 at 12:17 PM Steve Green <
> > <EMAIL REMOVED> >
> > wrote:
> >
> > > Who is saying it's absolutely necessary? I can see how it might
> > > cause accessibility issues when the layout of pages change as they
> > > are
> zoomed,
> > > but it's by no means inevitable.
> > >
> > > That said, I tend to regard the presence of "z-index" attributes
> > > as a warning that there might be other nastiness because it
> > > suggests the
> > design
> > > is fundamentally flawed. It's the same as when you see positive
> > "tabindex"
> > > attributes.
> > >
> > > Steve Green
> > > Managing Director
> > > Test Partners Ltd
> > >
> > >
> > > -----Original Message-----
> > > From: WebAIM-Forum < <EMAIL REMOVED> > On
> > > Behalf Of Ilana Gordon
> > > Sent: 27 May 2020 16:58
> > > To: WebAIM Discussion List < <EMAIL REMOVED> >
> > > Subject: [WebAIM] Z-Order and Tag Order Need to Match?
> > >
> > > Can the group weigh in on the latest techniques and efficacy
> > > regarding Z-Order and Tag Order having to match and why this would
> > > be absolutely necessary for Accessibility?
> > >
> > > I'm having many discussions with government 508 officers going
> > > around
> in
> > > circles regarding this issue.
> > >
> > > Any info is appreciated.
> > > Ilana
> > >
> > > --
> > > Ilana Gordon
> > > CEO
> > > Word Wizards, Inc
> > > 8609 2nd Avenue, Unit 406-B
> > > Silver Spring, MD 20910
> > > *v.*301-986-0808 *fax.*301-986-0809
> > > *Direct: 240-380-2639*
> > > https://nam05.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.wordwizardsinc.com%2F&amp;data%7C01%7Cmichael.vaughn%40yale.edu%7C5723580863ad4fe8047208d8026cd97e%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C637262013830988780&amp;sdata=dgirrkhrBNXEoNLMmAMYmcYTWjFWQQSC3sFoLfro%2F5Y%3D&amp;reserved=0
> > > > > > > archives
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> > > > > >
> >
> >
> > --
> > Ilana Gordon
> > CEO
> > Word Wizards, Inc
> > 8609 2nd Avenue, Unit 406-B
> > Silver Spring, MD 20910
> > *v.*301-986-0808 *fax.*301-986-0809
> > *Direct: 240-380-2639*
> > https://nam05.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.wordwizardsinc.com%2F&amp;data%7C01%7Cmichael.vaughn%40yale.edu%7C5723580863ad4fe8047208d8026cd97e%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C637262013830988780&amp;sdata=dgirrkhrBNXEoNLMmAMYmcYTWjFWQQSC3sFoLfro%2F5Y%3D&amp;reserved=0
> > > > > > archives at https://nam05.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwebaim.org%2Fdiscussion%2Farchives&amp;data%7C01%7Cmichael.vaughn%40yale.edu%7C5723580863ad4fe8047208d8026cd97e%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C637262013830988780&amp;sdata=2INL3QV9tvizFl7DMBAybse%2F%2B6xgtThi8U3sNir1U7E%3D&amp;reserved=0
> > > >
> > > archives at https://nam05.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwebaim.org%2Fdiscussion%2Farchives&amp;data%7C01%7Cmichael.vaughn%40yale.edu%7C5723580863ad4fe8047208d8026cd97e%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C637262013830988780&amp;sdata=2INL3QV9tvizFl7DMBAybse%2F%2B6xgtThi8U3sNir1U7E%3D&amp;reserved=0
> >


--
Ilana Gordon
CEO
Word Wizards, Inc
8609 2nd Avenue, Unit 406-B
Silver Spring, MD 20910
*v.*301-986-0808 *fax.*301-986-0809
*Direct: 240-380-2639*
https://nam05.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.wordwizardsinc.com%2F&amp;data%7C01%7Cmichael.vaughn%40yale.edu%7C5723580863ad4fe8047208d8026cd97e%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C637262013830988780&amp;sdata=dgirrkhrBNXEoNLMmAMYmcYTWjFWQQSC3sFoLfro%2F5Y%3D&amp;reserved=0