There are cases where the implementer is bridging from a toolkit and has no control over that toolkit's structuring and IA2_RELATION_MEMBER_OF is needed. But do we need the reverse? What is the use case for IA2_RELATION_GROUPING_OBJECT_FOR? Grouping objects don't get focus. In a virtual cursor scenario I haven't seen AT announce a group's members when the cursor lands on the grouping object (but the converse relation is needed when the cursor is on a contained accessible).
I also notice that noone has argued for adding IA2_RELATION_POPUP_INITIATOR_FOR (the converse of IA2_RELATION_POPUP_FOR). I'll not include it if there is no justification for it. Pete On 2/25/12 11:53 AM, Alexander Surkov wrote: > I'd say if having a relation means either we don't have good > assumptions of the hierarchy or it's more performant way than tree > traversal. In either case we want to have opposite relation expect the > case when related accessible is a child (not performant to run through > children but performant to get a parent). > > IA2 says about member_of relation > (http://accessibility.linuxfoundation.org/a11yspecs/ia2/docs/html/group__grp_relations.html#gb0213d9d1193fb6e6f50e1f2115aa911): > It is also possible that each member has multiple additional targets, > e.g. one for every other member in the group. That makes me think you > can't do a good guess about hierarchies. And either we need to have > opposite relation or fix a spec. > > Btw, Firefox exposes member_of on child accessibles from subtree of > ARIA atomic regions only. I don't think opposite relation is > applicable here. I think I agree with Peter Korn that we shouldn't > expose relations in every case so if AT has a good idea about > hierarchies then relations should be used as fallback when hierarchies > fail. That's what we do for node_child_of relation for example. > > Thanks. > Alex. > > > On Sat, Feb 25, 2012 at 8:06 AM, James Teh <[email protected]> wrote: >> On 25/02/2012 1:28 AM, Peter Korn wrote: >>> It has been a LONG time since I wrote any screen reader code on Windows, >>> but I recall clearly that the old Win32 radio button group box control >>> was always a peer of the buttons it was grouping, not the parent. >> Correct. However, if you're using something that implements IA2, someone has >> obviously already gone to the trouble of implementing their own >> accessibility objects, so they may as well sanitise the hierarchy as well >> (i.e. make the grouping a parent). If anyone can come up with use cases >> contradicting this, there's a good case for the new relation. Otherwise, >> probably not. >> >> Jamie >> >> -- >> James Teh >> Director, NV Access Limited >> Email: [email protected] >> Web site: http://www.nvaccess.org/ >> Phone: +61 7 5667 8372 >> >> _______________________________________________ >> Accessibility-ia2 mailing list >> [email protected] >> https://lists.linuxfoundation.org/mailman/listinfo/accessibility-ia2 > _______________________________________________ > Accessibility-ia2 mailing list > [email protected] > https://lists.linuxfoundation.org/mailman/listinfo/accessibility-ia2 > -- *Pete Brunet* a11ysoft - Accessibility Architecture and Development (512) 467-4706 (work), (512) 689-4155 (cell) Skype: pete.brunet IM: ptbrunet (AOL, Google), [email protected] (MSN) http://www.a11ysoft.com/about/ Ionosphere: WS4G
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