Subject: Re: [docbook-apps] tagged and accessible PDF document with DocBook
On 27/04/2017 18:27, Dave Pawson wrote:
On 27 April 2017 at 17:49, Tony Graham <email@example.com> wrote:Which brings me to... 8. You have a comment about preferring a flat rather than nested ToC structure. You can represent a hierarchical ToC structure in Tagged PDF, but I don't know whether flat or hierarchical is better for people using assistive technology. Dave Pawson may know.I think 'visual' presentation isn't an issue? When text is read by a machine, one line with indent x is the same as one with indent y. I'd suggest a flat structure would be more readily accessible, unless each entry is numbered etc?
I agree that indenting in the formatted output wouldn't affect how the text is read out by a machine. However, it seems to me that a hierarchical structure would give the option of reading/being read only the top-level ToC entries in turn and then 'expanding' into the ToC group that is of interest. Presumably any reader software could also provide options for jumping out of the current ToC group or to the next/previous ToC group. The difference between a flat and a hierarchical structure would be like having the bookmarks sidebar in your PDF viewer permanently expanded or having it start out collapsed along with only being able to use the arrow keys to move through the visible entries. I'll note that the hierarchical EPUB ToC structure derives from the Digital Talking Book (DTB) NCX structure, but the NISO standard  doesn't provide any rationale for the design. I'll also note that that's the closest that I can come to finding anything to support the idea that hierarchical is better. Regards, Tony Graham. -- Senior Architect XML Division Antenna House, Inc. ---- Skerries, Ireland firstname.lastname@example.org  http://www.niso.org/workrooms/daisy/Z39-86-2005.html#NCX