New SVG 2 Changes

Hello all,

Nikos, Tav & I have been busy fussing with the SVG spec this week.  There
are a few changes that are relevant to the accessibility team:


   1. Re-write of the section on title & desc.  New text is here:
   https://svgwg.org/svg2-draft/struct.html#DescriptionAndTitleElements
   A description of the major changes is in the (closed) pull request here:
   https://github.com/w3c/svgwg/pull/170
   If you notice any outstanding issues, please file a new issue.

   2. Allow nested links.  It already works in many browsers, and could
   definitely be useful.  But I'm not sure how the experience is from an
   accessibility perspective.
   Current spec text is here:
   https://svgwg.org/svg2-draft/linking.html#Links
   My JSBin test case is here:
   http://jsbin.com/sefapofaxi/1/edit?html,output There's an outer link
   with two elements (grey rectangle and orange ellipse), then an inner link
   with a blue ellipse that visually obscures the orange ellipse if it renders.

   3. We've removed the dual nature of the "mesh" element.  Now we have a
   "mesh" element that is a shape drawn to screen and a separate
   "meshGradient" element that defines the coloring pattern.  We'll need to
   add "meshGradient" to the SVG-AAM, but it will be straightforward, since
   it's a never-rendered element.  The changes we made to define "mesh" as
   role="img" are still valid.

   4. We've added better rules for language selection for switch elements
   (allowing the browser to use ranked language preferences from the user);
   text here: https://svgwg.org/svg2-draft/struct.html#SwitchElement. These
   are consistent with the clearer definition of language selection for title
   & desc, linked above.

I think those are the main changes that are relevant from an accessibility
perspective.  The first point should close a few of my Tracker issues for
the Task Force, but I'll review that later to see if anything's still
missing.

I still need to clean up the section on element default & allowed roles, to
match the latest SVG-AAM.  I was going to propose a re-write & let the TF
comment on the 2 options.  I'll try to have that ready in time for the call
next week.

Bye from Amsterdam,
Amelia