Re: [g-a-devel]Implementing ATK on Custom Widgets

["Padraig O'Briain" <Padraig Obriain sun com>]

Marc,

What I have done is put the data you had in the ZvtAccessible structure into a 
new ZvtAccessiblePriv structure and provide a function 
zvt_accessible_get_private_data() which returns a pointer to the 
ZvtAccessiblePriv structure for a ZvtAccessible structure

The code in the _get_type() which calculates the size of the instance data is 
changed, compared to the code in htmlviewaccessible.c, to be the size of the 
instance data for the parent class plus the size of the ZvtAccessiblePriv 
structure.

I do not have a strong opinion on whether we should ask the release tem if we 
can install some header files. If we do install some header files, I think that 
we need to be willing to install them all. My only opinion on installing the 
header files is that I would prefer that that it would not imply that the 
interfaces defined in the header files are public and stable.

Padraig


> X-Sender: mm128299 bes central sun com
> To: "Padraig O'Briain" <Padraig Obriain sun com>, michael ximian com
> Subject: Re: [g-a-devel]Implementing ATK on Custom Widgets
> Cc: gnome-accessibility-devel gnome org
> Mime-Version: 1.0
> 
> The files don't build.  I removed them from Gail since GailWidget isn't 
> exposed, and because they contain instance data, they won't build in libzvt 
> itself.  Padraig, I'll send you a tarball off list-- but could you outline 
> what you're proposing?
> 
> exposing GailWidget seems like the least painful path-- and the most 
> straightforward for developers unfamiliar with accessibility.  We can come 
> up with clever tricks to implement this stuff, but if they aren't 
> straightforward, they'll pose barriors to implementing accessibility on 
> custom widgets, which IMHO is to be avoided.
> 
> Marc
> 
> At 05:18 PM 1/23/2002 +0000, Padraig O'Briain wrote:
> 
> > >
> > > Hi Mark,
> > >
> > > On Wed, 2002-01-23 at 11:57, Marc Mulcahy wrote:
> > > > Still attempting to get libzvt accessibility support running.  We 
> > need to
> > > > make a decision as to how and what parts of gail should be 
> > exposed.  I've
> > > > run into an issue with the technique used to provide accessibility for
> > > > gtkhtml2-- namely that the accessibility implementation class can't have
> > > > any data of its own.  This won't work for libzvt, since it *has* to keep
> > > > some callback pointers laying around.  I could attach a private data
> > > > structure to the accessible object using a quark or some such horrid and
> > > > ugly thing, but this seems to break the GNOME standard of 
> > straightforward
> >code.
> > >
> > >       I thought you spent some time doing work to make this unnecessary 
and
> > > AFAIR at the time I pointed out that you wouldn't be able to add
> > > instance data, anyway.
> >
> >Marc,
> >
> >I discussed this with Bill, and we may be able to come up with something.
> >
> >Could you send me the header files and sources files which are causing you 
> >the
> >problem and I will try to flesh out our idea.
> >
> >
> > >
> > > > I propose that at least we expose GailWidget, so that accessibility
> > > > implementations for custom widgets don't have to re-invent the wheel for
> > > > the basic functions like name, description, screen geometry etc.
> > >
> > >       Sigh; what headers does gail install currently ? seemingly none - 
> > that
> > > seems good, but ...
> >
> >Not quite; there are some include files in 
> >/opt/gnome-2.0/include/gail-1.0/util.
> >
> > >
> > >       I suppose the release team need consulting - there are rumblings 
> > going
> > > on over there; either way I have no particular conceptual problems with
> > > gtkhtml2 depending on gail, or gail exporting some minimal API to help
> > > code re-use.
> > >
> > >       Regards,
> > >
> > >               Michael.
> > >
> > > --
> > >  mmeeks gnu org  <><, Pseudo Engineer, itinerant idiot
> > >
> > > _______________________________________________
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> > > Gnome-accessibility-devel gnome org
> > > http://mail.gnome.org/mailman/listinfo/gnome-accessibility-devel
>