ntg-context - mailing list for ConTeXt users
 help / color / mirror / Atom feed
* Re: Accessibility and Tagged PDFs: Bugs and Feature Requests
@ 2015-07-01  6:08 Christoph Reller
  0 siblings, 0 replies; 17+ messages in thread
From: Christoph Reller @ 2015-07-01  6:08 UTC (permalink / raw)
  To: ntg-context


[-- Attachment #1.1: Type: text/plain, Size: 1376 bytes --]

On Tue, Jun 30, 2015 at 10:33 AM,luigi scarso <luigi.scarso@gmail.com>
 wrote:

> On Sun, Jun 28, 2015 at 12:59 PM, Dr. Dominik Klein <
> Dominik.Klein@outlook.com> wrote:
>
> > Context is the only Tex-based system that allows to properly tag a pdf.
> > Tagged PDFs are one major requirement for accessibility.
> >
> > Indeed, in several large organizations/universities, accessibility is
> > mandated by law, and this is a major obstacle for using Tex. In practice
> > compliance is often assessed with Acrobat Pro's
> > accessibility checker.
> >
> > Context produces a nice tag-structure, but there are some minor issues
> > that prevent compliance to [1], and hence Acrobat Pro complains during
> the
> > check.
>
> Thank you for the report .
> It would be nice to have a pdf made by context using \nopdfcompression
> that have all these issues together with the report emitted by acrobat.
> Last time I have checked a pfd/a-1a made by context it was all ok, but it
> was time ago and maybe not
> all the features were tested deeply.
>
> --
> luigi
>

Hello and thank you for raising these issues.

Note that there is a free and very good PDF accessibility checker:
http://www.access-for-all.ch/en/pdf-lab/pdf-accessibility-checker-pac.html
You can easily generate a detailed report with this tool. It does, however,
not check for PDF/A-1a conformance.

Cheers, Christoph

[-- Attachment #1.2: Type: text/html, Size: 2172 bytes --]

[-- Attachment #2: Type: text/plain, Size: 485 bytes --]

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

^ permalink raw reply	[flat|nested] 17+ messages in thread
[parent not found: <mailman.1.1435831202.18251.ntg-context@ntg.nl>]
* Re: Accessibility and Tagged PDFs: Bugs and Feature Requests
@ 2015-07-03  8:12 Dominik Klein
  2015-07-03 17:19 ` Hans Hagen
  0 siblings, 1 reply; 17+ messages in thread
From: Dominik Klein @ 2015-07-03  8:12 UTC (permalink / raw)
  To: ntg-context


[-- Attachment #1.1: Type: text/plain, Size: 2848 bytes --]


On Wed Jul 1, 18:47:57 CEST 2015, Hans Hagen wrote:
>> /Artifact
>>    BMC
>>    ..
>>    EMC
>
>i'll add the simple variant (i see no need to add properties to 
>something that is supposed to be ignored anyway)

thanks!


>> 2.) Images without alternate text:
>
>i'll pass the label to the tag as alt text
>
>\externalfigure[t:/sources/cow.pdf][label=whatever]

Again, thanks!

>> 3.) Tag names of the resulting tag structure:
>> Section 14.8.4 of [1] defines standard structure types, 
>
>The set of those standard tags is rather limited and imo one of the 
>craziest things in pdf as we then end up with abuse of those html tags 
>(and probably endless discussions on what to map onto what). I don't 
>even have a clue what it would add to the concept either. Reflow is a 
>braindead thing anyway.

Indeed, the set of those tags is very limited. Unfortunately, as 
far as I know, some screen readers (for the visually impaired)
use these as navigation aids, i.e. press button "jump to next section",
and the reader will look for the next section marked as <Sect> or something.

Is it difficult to make the mapping user-defineable in the source tex-file? 
Say, like such a command:
\definemapping[
  section=Sect,
  sectiontitle=H
  sectionnumber=H,
  ...
  tablerow=TR
  ...
]

It would then give users the control on what to map onto what, depending
on what kind of documents they create.

>> All in all, these seem to be the only issues that prevent accessible PDF
>> documents with context. For those within an organization where
>> accessibility is required legally for all publications, compliance to at
>> least Acrobat Pro's checks is a huge issue. I do not know how difficult
>> these things are to implement in Context (personally I am just lost in
>> the code), but looking at e.g. tex.stackexchange
>> for question related to accessibility, this is indeed a major obstacle
>> for several people.
>
>In fact adding pdf tagging to context was rather easy. Some time was 
>So, it's not that difficult to add features, more a matter of priorities 
>and motivation (apart from the fact that my acrobat is a bit old by now 
>so I cannot really test).

I can fully understand that such things are not of the highest priority. 
Nevertheless accessibility plays more and more a role, e.g. lately, even
conferences like http://chi2015.acm.org/authors/guide-to-an-accessible-submission/
require accessible pdfs (the workflow they suggest, i.e. tagging a pdf
by acrobat pro after compiling of course doesn't work at all - the generated
structure is useless).

Hence, for some users, it makes all the difference. For example for me and
some other friends, it would allow to change from using Microsoft Word to 
a ConTeXt based workflow. 

cheers

- Dominik
 		 	   		  

[-- Attachment #1.2: Type: text/html, Size: 3585 bytes --]

[-- Attachment #2: Type: text/plain, Size: 485 bytes --]

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

^ permalink raw reply	[flat|nested] 17+ messages in thread
* Accessibility and Tagged PDFs: Bugs and Feature Requests
@ 2015-06-28 10:59 Dr. Dominik Klein
  2015-06-30  8:32 ` luigi scarso
                   ` (4 more replies)
  0 siblings, 5 replies; 17+ messages in thread
From: Dr. Dominik Klein @ 2015-06-28 10:59 UTC (permalink / raw)
  To: ntg-context

Context is the only Tex-based system that allows to properly tag a pdf. 
Tagged PDFs are one major requirement for accessibility.

Indeed, in several large organizations/universities, accessibility is 
mandated by law, and this is a major obstacle for using Tex. In practice 
compliance is often assessed with Acrobat Pro's
accessibility checker.

Context produces a nice tag-structure, but there are some minor issues 
that prevent compliance to [1], and hence Acrobat Pro complains during 
the check. The main issues are:

1.) Elements that are not contained in the structure tree are not marked 
as an artifact. Consider this example:

-------------------------------
\setuptagging[state=start]

\setuppagenumbering
[location=,
  alternative=doublesided]

\setupheadertexts
   [{Chapter~\getmarking[chapternumber]\hskip1em\getmarking[chapter]}]
   [{Header Right}]
   [{Header Left}]
   [{Chapter~\getmarking[chapternumber]\hskip1em\getmarking[chapter]}]

\setupfootertexts
   [Organization Name]
   [pagenumber]
   [pagenumber]
   [Organization Name]

\starttext
\startfrontmatter
something
\stopfrontmatter

\startbodymatter
some more text here
\stopbodymatter
\stoptext
-------------------------------

Header, footer, pagenumber etc. will not be included in the tag 
structure. Of course this makes absolutely sense and is correct, however 
according to Section 14.8.2.2.2 of [1], then this content that is not in 
the structure tree should be marked as an artifact, i.e.

/Artifact
   BMC
   ..
   EMC

or in an advanced way with /Artifact PropertyList where the type of 
Artifact can be defined. It would be nice if those elements that are not 
included in the tag tree would be marked as artifacts by default. The 
same holds for \startelement[ignore] when one wants to explicitly remove 
something from the structure tree.

2.) Images without alternate text:
According to Section 14.9.3 of [1], alternate descriptions in human 
readable text should be provided for images. It would be really helpful,
if these could be defined in the source tex file, and then automatically
added when creating the object in the structure tree. I.e. it would be
nice to have something like:

\placefigure[top][Image Reference]{Caption}{
\externalfigure[cow.pdf][width=10cm][alternate text = "This images shows 
a beautiful cow."]
}

The same holds for formulas: Whereas the mathml-like tagging of Context 
is very advanced, sometimes it might be still helpful to supply a 
textual description (alt-text ="The definition of the Pythagorean 
theorem: a^2 + b^2 = c^2")

3.) Tag names of the resulting tag structure:
Section 14.8.4 of [1] defines standard structure types, such as <H>, 
<P>, <Sect> etc. Context creates a tag-tree that uses names directly 
representing the structure names of the context laguage, such as 
<sectiontitle>. This should however be mapped to something standard, 
such as <H>. Interestingly these mappings seem to have been considered 
in strc-tag.mkiv but I was unable to generate such a tagged pdf. 
Editing/Outcommenting things in strc-tag.mkiv didn't work for me. It 
would be nice if there was a switch somewhere, i.e. 
\setuptagging[state=start,tagnames=pdf17] - or maybe I overlooked something?

4.) Acrobat Pro always complains that the language for the whole 
document is not set.

5.) Tables
The generated structure looks something like this:
<table>
  <tablerow>
    <tablecell>
    ...
  <tablerow>
    <tablecell>
  ...

Here, not only are the tag names non-compliant, also the tag structure
should distinguish between the table header (THead), and table rows 
(TBody), c.f. Section 14.8.4.3.1 of [1]. A simple heuristic would be
to always put the first line into THead tags, and the rest of the able 
into TBody.

6.) It would be nice if a flat tag structure could be created 
optionally. This is not a required feature according to [1], and in fact 
a properly nested structure is surely preferable for the final output; 
for debugging or checking during document creation however, a flat 
structure tree sometimes is easier to browse through.

All in all, these seem to be the only issues that prevent accessible PDF 
documents with context. For those within an organization where 
accessibility is required legally for all publications, compliance to at 
least Acrobat Pro's checks is a huge issue. I do not know how difficult 
these things are to implement in Context (personally I am just lost in 
the code), but looking at e.g. tex.stackexchange
for question related to accessibility, this is indeed a major obstacle 
for several people.

cheers

- Dominik


[1] ISO 32000-1:2008, available at
http://www.adobe.com/devnet/pdf/pdf_reference.html
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

^ permalink raw reply	[flat|nested] 17+ messages in thread
end of thread, other threads:[~2015-07-06  8:01 UTC | newest]

Thread overview: 17+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-07-01  6:08 Accessibility and Tagged PDFs: Bugs and Feature Requests Christoph Reller
     [not found] <mailman.1.1435831202.18251.ntg-context@ntg.nl>
2015-07-03 13:16 ` Christoph Reller
2015-07-03 17:09   ` Hans Hagen
  -- strict thread matches above, loose matches on Subject: below --
2015-07-03  8:12 Dominik Klein
2015-07-03 17:19 ` Hans Hagen
2015-07-04 16:45   ` Alan BRASLAU
2015-07-05 11:11     ` Hans Hagen
2015-07-05 20:04       ` Dr. Dominik Klein
2015-07-06  8:01         ` Hans Hagen
2015-06-28 10:59 Dr. Dominik Klein
2015-06-30  8:32 ` luigi scarso
2015-06-30  9:00 ` Alan BRASLAU
2015-06-30 15:58   ` Dominik Klein
2015-06-30 16:02     ` luigi scarso
2015-07-01 15:51 ` Hans Hagen
2015-07-01 16:47 ` Hans Hagen
2015-07-01 17:02 ` Hans Hagen

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).