Re: Accessibility and Tagged PDFs: Bugs and Feature Requests

[Hans Hagen <pragma@wxs.nl>]

On 7/5/2015 10:04 PM, Dr. Dominik Klein wrote:
> Am 05.07.15 um 13:11 schrieb Hans Hagen:
>> On 7/4/2015 6:45 PM, Alan BRASLAU wrote:
>>> On Fri, 3 Jul 2015 19:19:58 +0200
>>> Hans Hagen <pragma@wxs.nl> wrote:
>> sure but in the meantime we need to find a way to determine what works
>> and what not, for instance, as i mentioned that context already adds a
>> rolemap
>>
>> 11 0 obj
>> << /ParentTree 12 0 R /K 29 0 R /RoleMap << /sectiontitle /H /section
>> /Sect /sectionnumber /H /document /Div >> /Type /StructTreeRoot >>
>> endobj
>>
>> we have no way to check if that works (so maybe we need to have a page
>> on the wiki with a viewer/functionality matrix)
>>
>
> The whole rolemap thing and how Acrobat Pro handles it leaves me
> somewhat puzzled.
>
> Taking https://github.com/asdfjkl/tex-access/blob/master/rolemap.tex and
> compiling will give the rolemap as Hans described above. Looking at the
> Tag structure, this seems to be ignored by acrobat (but why?), see
> https://github.com/asdfjkl/tex-access/blob/master/rolemap.PNG

i always suspect a chicken-egg issue there: someone wants a feature, it 
gets added to pdf, then there is waiting for some typesetting engine to 
support it, and then acrobat might do something with it and afterwards 
the spec gets adapted (or interpretation is adapted) .. it happened with 
widgets and such

the interesting thing about tex is that we can easily adapt to such new 
features but have no way of testing it

(some relates to the fact that pdf is both a document format and a 
storage format for e.g. illustrator so it's some hybrid)

maybe it's just: if we have tags it is accessible by definition, no 
matter if it can be used or not

> What would be expected is this, right? After all, the rolemap should be
> interpreted, shouldn't it (mapping /H to /H1 was a mistake of mine, but
> it doesn't change the fact).
> https://github.com/asdfjkl/tex-access/blob/master/rolemap2.PNG
> After changing things manually in the tag editor in acrobat, and saving
> the pdf again, this is obtained:
> https://github.com/asdfjkl/tex-access/blob/master/rolemap_edited.pdf

maybe the H etc is only used with reflow ... and reflow is weird in 
itself as one can then better provide an html file alongside the pdf

it makes me wonder how a complex doc with mostly H's would look / be 
interpreted as that is then the dominant structure thing

> Note this:
> << /RoleMap << /document /Div /sectionnumber /H /sectiontitle /H
> /section /Sect >> /Type /StructTreeRoot /ParentTree 12 0 R /K 29 0 R >>
>
> and also the different structure elements at the start of the pdf...

the order of /Key values in the dicts is not important and hashes are 
often unordered (different per application or even per run for some 
applications for security reasons); when you play with widgets you will 
also observe that acrobat adds rendered content to the file as addition 
to the key/values

Hans

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