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Subject: Re: [docbook-apps] tagged and accessible PDF document with DocBook
On 3 April 2017 at 21:12, Holger Bast <holgerbast@gmx.de> wrote: > If there is no specification in xsl:fo how to apply the right structural information there will be no normative instance > and all processors will handle these kind of information in their own manner. I No, xsl-fo has no document wide 'structure'. If any, that should come from your source XML and be carried over to the fo, then PDF. regards Dave > Here are some of my resources, maybe they can help you: > > The following document gives a short overview how xml structural information can be applied to pdf. The document > contains also a list of elements that should be tagged (see table 1) > https://pdfs.semanticscholar.org/9a51/cd67046a81d4e02d6b4b35fa402bacc892f8.pdf > > PAC 2 - PDF Accessibility Checker (PAC 2) > PAC is an easy to use tool to check if your pdf document is accessible. If not PAC will show you the problems in the > structure as well as inside the document. > http://www.access-for-all.ch/en/pdf-lab/pdf-accessibility-checker-pac.html > > And last but not least the pdf specification document. I didn't read the document yet. I try to get my hands on it in > the next days. > ISO 14289-1:2014 - Document management applications -- Electronic document file format enhancement for accessibility -- > Part 1: Use of ISO 32000-1 (PDF/UA-1) > https://www.iso.org/standard/64599.html > > Holger > > > > > Bob Stayton wrote: >> Hi Tony, >> Thanks for chiming in. I guess I cannot expect to get an XSL-FO standard for PDF tagging. If we are going to implement >> it, we will need to use the facilities in each XSL-FO processor. Given that, I want to make sure what is output is >> usable, that is, meets the needs and standards of the accessibility community. >> >> I just ran across a webpage titled: >> >> http://508compliantdocumentconversion.com/finally-u-s-access-board-updates-interpretation-of-section-508/ >> >> which says that WCAG 2.0 has been designated as the Reference Standard of section 508 of the Rehabilitation Act. >> >> I get that WCAG 2.0 is a W3C standard, but I don't know much about it. Do you think I should spend time studying this as >> the correct reference for implementing standard and usable tags in DocBook XSL? >> >> Bob Stayton >> Sagehill Enterprises >> bobs@sagehill.net >> >> On 4/3/2017 11:52 AM, Tony Graham wrote: >>> On 03/04/2017 18:07, Bob Stayton wrote: >>>> Hi Holger, >>>> No, you didn't miss anything. The DocBook XSL stylesheets currently do >>>> not provide support for tagged PDFs. >>>> >>>> That said, my short investigation shows that implementing such support >>>> is nontrivial. Keep in mind that the DocBook stylesheets don't actually >>>> create a PDF. The stylesheets generate a FO version of the document, >>>> and then an XSL-FO processor converts that to a PDF. So DocBook XSL has >>>> to generate additional markup in the FO output that an XSL-FO processor >>>> can convert to PDF tags. >>>> >>>> It looks like each of the XSL-FO processors commonly used with DocBook >>>> (FOP, XEP, and Antenna House) have different extensions for implementing >>>> the FO needed to generate the PDF accessibility tags. For example: >>>> >>>> FOP has fox:alt-text >>>> XEP has rx:pdf-structure-tag >>>> AH expects axf:pdftag >>> >>> Not quite. If you produce either Tagged PDF or PDF/UA using AH Formatter >>> from either XSL-FO or HTML/XML+CSS, then AH Formatter will default to >>> generating a PDF Tag based on the type of the current element. For >>> example, fo:root generates 'Document' and fo:table generates 'Table'. >>> See https://www.antennahouse.com/product/ahf64/ahf-pdf.html#taggedpdf >>> >>> @axf:pdftag is for when you want to override a default mapping. See >>> https://www.antennahouse.com/product/ahf64/ahf-ext.html#axf.pdftag. You >>> can use @axf:pdftag to set a different standard PDF Tag for that element >>> or you can provide your own non-standard Tag name, in which case AH >>> Formatter will also generate the mapping from the non-standard name to >>> the default PDF Tag for that element so that the requirement of the >>> spec for Tagged PDF for having a mapping to a known Tag is met. >>> >>>> This situation is similar to when PDF bookmarks were first implemented. >>>> Each XSL-FO processor had their own extensions to implement that >>>> feature, and DocBook XSL had to support all three extensions. When XSL >>>> 1.1 standardized the markup for bookmarks, then all the XSL-FO >>>> processors eventually implemented that standard and so did DocBook XSL. >>> ... >>>> I would be interested in adding PDF tagging to DocBook XSL. It would >>>> help if there were a clear spec for how to do so. If I have to figure >>>> it out for each of three XSL-FO processors, that's going to take some >>>> time. >>> >>> There is no current W3C Working Group for XSL-FO. There is the Print and >>> Page Layout Community Group (https://www.w3.org/community/ppl/), of >>> which I am the Chair, but it takes more than just a venue to produce a >>> spec with enough impetus to convince multiple vendors/teams to implement >>> it. >>> >>> Regards, >>> >>> >>> Tony Graham. >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: docbook-apps-unsubscribe@lists.oasis-open.org >> For additional commands, e-mail: docbook-apps-help@lists.oasis-open.org >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: docbook-apps-unsubscribe@lists.oasis-open.org > For additional commands, e-mail: docbook-apps-help@lists.oasis-open.org > -- Dave Pawson XSLT XSL-FO FAQ. Docbook FAQ. http://www.dpawson.co.uk
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