Re: SVG markup thoughts

Rich,

For things that should not navigate you can provide special roles that
indicate they shouldn't be navigated or read to AT.  The semantic roles:
none and background could be defined to not be part of navigation and not
presented to AT.  I propose a semantic role for background since I see
where it will be needed when increasing contrast.

When I look at charts generated by charting engines like IBM's RAVE, they
tend to group things semantically.  For instance the non navigable parts of
an axis like the short tick lines, are already grouped together.  The few
STEM examples seem to be organized in a sensible manner as well. So I don't
see where semantic role inheritance will be a problem.

Stuff where text is turned into shapes seem to have problematic structures,
like the map of Argentina as all the parts of the same word do not
necessarily fall in the same graphic object or parts of different labels
may be in the same graphic object. This can be problematic.

                                                              
                                                              
                    Regards,                     Fred         
                                                              
                   Fred Esch                                  
       Accessibility, Watson Innovations                      
    AARB Complex Visualization Working Group                  
                     Chair                                    
        W3C SVG Accessibility Task Force                      
                   IBM Watson                                 
                                                              
                                                              






From:	Richard Schwerdtfeger/Austin/IBM
To:	Fred Esch/Arlington/IBM@IBMUS
Cc:	public-svg-a11y@w3.org
Date:	05/14/2015 10:23 AM
Subject:	Re: SVG markup thoughts


Fred, I understand the going nuts, ... but what this also means is that if
you do the inheritance approach you also have to deal with:

- situations where you don't want it inherited
- overriding roles on elements that you selectively don't want to inherit
the role.

This is extremely complicated for authors.

We would also need to restrict this to specific roles. For widgets this
will be a disaster.

Rich


Rich Schwerdtfeger




From:	Fred Esch/Arlington/IBM
To:	Richard Schwerdtfeger/Austin/IBM@IBMUS,
            <public-svg-a11y@w3.org>
Date:	05/14/2015 09:17 AM
Subject:	SVG markup thoughts


Rich,

I think it is important to be able to inherit the semantic role from an
ancestor for three reasons. Semantic inheritance avoids bloat, it keeps
authors from going nuts and simplifies guidance. Whenever you bloat your
resource, products will argue against a bloated resource because it loads
slower and takes more memory. We need to allow inheritance from any level
of ancestor as intermediate groups are often generated for a change in
style. For example, in the airline (delay) chart, the grid lines for the
months are grouped by location of the text. These groupings are are more
space saving than putting the attributes in each grid line and we should
not discourage non semantic groupings.

In my markup, when groups should be part of navigation, I provide one (or
possibly two) of - title, desc, aria- label, labeledby or describedby. Non
semantic grouping (like the airline chart month grid lines for text
location) don't have a title, desc, aria- label, labeledby or describedby
and are ignored by navigation.

I am doing markup to support navigation and AT interpretation.  Markup for
media query style changes for low vision, color blind and coga will come
later. In navigation experiments, regardless of the type of graphic, if you
have groups that represent features, reasonable things happen (using a tree
style navigation) when the groupings are done well.

So if it will be a problem to allow role attribute inheritance, then I
suggest we create a semantic role or graphic role (g-role) attribute.
                                                                 
                                                                 
                    Regards,                     Fred            
                                                                 
                   Fred Esch                                     
       Accessibility, Watson Innovations                         
    AARB Complex Visualization Working Group                     
                     Chair                                       
        W3C SVG Accessibility Task Force                         
                   IBM Watson