Re: inaccessible treeviews and tables

[Piñeiro <apinheiro igalia com>]

Hi,

I will try to answer your question as best as I can.

As you say, sometimes a 3rd party gtk app developer creates a custom
cell renderer in order to add some new visual stuff. The accessibility
related are not skipped. The already in place cell renderer
accessibility is used. But if the new cell renderer uses something
totally different to render text, then the gtk+ cell render accessible
object would not be valid. In that case you would need to provide a
custom accessibility object for that custom cell renderer. For the rest
of this email, I will call them CustomCellRenderer and
CustomCellRendererAccessible

gtk_cell_renderer_class_set_accessible_type, is just the method that
relates a cell renderer with his accessible method. Is just a utility
method to avoid the need to redefine the method get_accessible for any
custom object. So for this case, once you have a
CustomCellRendererAccessible, you would need to call
gtk_cell_renderer_class_set_accessible_type on your CustomCellRenderer.

About caring on CellRenderer: as I said, there is already an
accessibility support of CellRenderer. So probably you just need to
focus on that CustomCellRenderer, where the information about name and
state are stored there (that would be the difference with a "vanilla"
CellRenderer), and then try to expose it via a CustomCellRenderAccessible.

About that transmission-gtk: after a quick look on Venom. I don't see
any custom cell renderer being created. As far as I see, they are using
GtkCellRendererText, that should be already supported. Are you sure that
in that case you are under a custom cell renderer problem?

Best regards

[1] https://developer.gnome.org/gtk3/3.12/GtkCellRendererText.html

On 07/05/2014 06:20 PM, Peter Vágner wrote:
> Hello,
> A while ago I was trying to get some understanding on how to make 3rt
> party gtk apps accessible. At that time Alejandro Piñeiro pointed me
> to some docs and bugzilla entries describing the current situation.
> Unfortunatelly I haven't still mastered that. I have at least realized
> and hopefully understood at least some verry basic things related to
> this.
> For example currently I am able to set accessible labels and I am able
> to add / tweak relations between labels and the interactive controls
> they are supposed to label. I know this is not a big deal but I have
> already tweaked an app or two this way and I know it works fine.
> Another thing what's currently on my radar are widgets that are often
> reported as tables or treeviews. Individual rows appear to be keyboard
> focusable however orca is unable to report their role and text.
> I guess the common scenario is that the app developers tend to
> subclass Gtk.CellRenderer to create more visually appealing design. In
> this case if I understand correctly the content is directly drawn to
> the widget surface and proper accessibility related properties are
> skipped from the implementation entirely.
> By reading gtk reference docs I have came accross a method
> gtk_cell_renderer_class_set_accessible_type () . That appears to be
> only info I was able to find related to Gtk.CellRenderer and
> accessibility. Can anyone please give me a hint so I might try move
> forward and try learning how to implement accessibility for a widget
> where Gtk.CellRenderer is used?
> Do I need to care about Gtk.CellRenderer or should I just set
> accessibility related properties such as label and description for the
> affected widgets without looking at Gtk.CellRenderer? How do I refer
> to multiple treeview colums or table cells in such implementation? Is
> there an app or just a code example I should look into to see this in
> action?
> I have seen widgets with incomplete accessibility like this in many
> apps but if my explanation is not accurate enough here are two from
> the top of my head. One is the list of torrents in the
> transmission-gtk svn://svn.transmissionbt.com/Transmission/trunk and
> the other is a contact list widget in a gtk3 based tox client called
> venom https://github.com/naxuroqa/Venom .
> I will be looking into this some more, it may take me a while like it
> took me ages to figure out and get used to labelling and related stuff
> so I am just trying maybe with some hint I might master it better this
> time.
>
> Thanks
>
> Peter
>
> _______________________________________________
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-- 
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Alejandro Piñeiro