RE: [g-a-devel]Gnome 2.0 : accessibility for the gnome-cd application

["JAYARAJ P R" <jayaraj rajappan wipro com>]

>No, that typically doesn't happen.  However consider a screenreader in
>"review" mode - it attempts to present to the braille user (or
>text-to-speech user) a line representing the text along a particular
>horizontal "row" of the screen.  If text is contained only in single
>lines arranged on items such as buttons, the screenreader uses the
>screen coordinates of the containing object.  For multiline text this
>doesn't work, thus multiline text must either be placed in individual
>(possibly non-focussable) AtkComponent-implementing AtkOBjects, as the
>name returned from atk_object_get_name (if the text is unattributed, and
>simple enough) or it is returned as AtkText, in which case character
>extents information should be provided.

As i understand from the discussions till now, there are 2 approaches which
we could follow to provide accessibility for the CDDisplay custom widget in
gnome-cd.

1.The first approach is to try to expose  separate AtkObjects for each
PangoLayout. Does it mean that we have to implement AtkComponent for the
container of the PangoLayout (which is the custom widget in this case)? Or
can we override the atk_component_ref_accessible_at_point() method for the
custom wiget, so that it returns different AtkObjects for each of the
PangoLayouts depending on the x and y values. Also, i guess we need to
implement a separate factory for the PangoLayout so that we can set the
accessible name and description for each of the PangoLayouts and the code
for this would reside in the application itself.

2. The second approach is to try to implement most of the AtkText interfaces
for the custom widget.

Which one do you think would be more appropriate in this particular case?

Regards,
Jayaraj

> -----Original Message-----
> From: gnome-accessibility-devel-admin gnome org
> [mailto:gnome-accessibility-devel-admin gnome org]On Behalf Of Bill
> Haneman
> Sent: Monday, February 04, 2002 5:33 PM
> To: mukund rajagopalan wipro com
> Cc: 'JAYARAJ P R'; gnome-accessibility-devel gnome org
> Subject: Re: [g-a-devel]Gnome 2.0 : accessibility for the gnome-cd
> application
>
> Hi Jayaraj:
>
> I agree with Mukund's reaction here.  Generally we don't like to NULLIFY
> large parts of an API if they have meaning in a given context.  We may
> nullify API that doesn't apply, but we try not to leave methods NULL
> just because they are inconvenient to implement.
>
> One point to consider is that for multi-line text a screenreader needs
> to know where the text is on the screen, particularly for screen-review
> mode of screenreaders.  That implies that multi-line text should always
> use AtkText (rather than just the accessible name property) and needs to
> implement the character extents method.
>
> If the text has attributes that might convey any information (in other
> words, attributes that aren't purely cosmetic) then AtkText is required.
>
> In the case of gnome-cd, a possible alternative would be to expose
> separate AtkObjects for each pango layout, and then you could attach a
> description to each field, along with a name which carried the actual
> text.
>
> However the 'gail' library already has code that can implement most of
> AtkText on behalf of a pango layout, so it may not be too much
> additional work to complete the job of implementing AtkText.  For
> comparison, keep in mind that GtkLabels implement AtkText.
>
> I don't think that we currently export the headers for re-using the
> pango-based AtkText implementations in gail, but perhaps we should
> (rather than recommending cut-and-paste from gail).  What do you think
> Padraig?  We'd have to request that this API be added, I believe.
> However if the alternative is cut-and-paste then the GNOME release team
> is likely to allow it, I think.
>
> Best regards,
>
> Bill
>
> Mukund wrote:
> >
> > Jayaraj,
> >
> > Having AtkText interface means you got to provide information on
> > cursor-location, selection, getting text after position, etc. You need
to
> > check if these functions could be implemented for the text in the
display
> > area. In other words, could you get information from the application to
> > support these interfaces?
> >
> > I see that you would NULLIFY most of the functions in AtkText which
means
> > this probably is not the right interface. In other words, an AT will
make
> a
> > query on all these functions only to find that they aren't implemented,
> > which is not nice to have it done that way.
> >
> > Bill/Padriag?
> >
> > Cheers,
> > Mukund.
> >
> > -----Original Message-----
> > From: gnome-accessibility-devel-admin gnome org
> > [mailto:gnome-accessibility-devel-admin gnome org]On Behalf Of JAYARAJ P
> > R
> > Sent: Monday, February 04, 2002 3:54 PM
> > To: gnome-accessibility-devel gnome org;
> > gnome-accessibility-list gnome org
> > Subject: [g-a-devel]Gnome 2.0 : accessibility for the gnome-cd
> > application
> >
> > Hi,
> >
> > The gnome-cd application has a custom widget called CDDisplay which
forms
> > the display area where the information about the time elapsed, album
name,
> > artist name etc appears. The parent of this CDDisplay custom widget is a
> > GtkDrawingArea. It contains 4 lines of PangoLayout each of which display
> > information about the time elapsed for the current track, album name and
> > artist name.
> >
> > As part of accessibility, i feel that this custom widget requires
AtkText
> > interface to be implemented. The atk_text_get_text() interface of
AtkText
> > would return the time elapsed, album name and artist name when the focus
> is
> > on the CDDisplay custom widget. Most of the other interfaces in AtkText
> > doesn't seem
> > to make enough sense in this case and would be no-op functions.
> >
> > Anyone got different ideas?
> >
> > Regards,
> > Jayaraj
> >
> > _______________________________________________
> > gnome-accessibility-list mailing list
> > gnome-accessibility-list gnome org
> > http://mail.gnome.org/mailman/listinfo/gnome-accessibility-list
> _______________________________________________
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> Gnome-accessibility-devel gnome org
> http://mail.gnome.org/mailman/listinfo/gnome-accessibility-devel
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