Re: inaccessible treeviews and tables

Hello,
Issue in transmission-gtk is just my guess I haven't yet tryed to tinker 
with its source code so I may really be absolutelly wrong with my 
assumption.
Venom developers are subclassing GTK_CellRenderer here 
https://github.com/naxuroqa/Venom/blob/master/src/ui/ContactListCellRenderer.vala 
. I can see they are also using GtkCellRendererText in order to change a 
GTK_COMBOBOX which remains accessible here 
https://github.com/naxuroqa/Venom/blob/master/src/ui/ContactListWindow.vala 
.
While creating my CustomCellRendererAccessible do I really have to do 
everything that is recommended here 
https://developer.gnome.org/accessibility-devel-guide/stable/gad-custom.html.en 
? As I said I have tried to retrieve a coresponding accessible by 
calling gtk_get_accessible(MyCustomCellRendererObject). I was able to 
manipulate that accessible and set its name and description however by 
testing with orca I have discovered changes I am trying to make result 
in changes to the parent object treeview in this case not individual 
rows which as I understand are represented by the CustomCellRenderer. 
Then I have tried to subclass a GTK_TreeViewColumn where the 
CustomCellRenderer is connected to by trying to create empty ATK_Object, 
overridding Get_Accessible() in my subclass. Of course this does not 
work. I haven't really understood where is the problem however I think 
It is just not possible to instantiate ATK_Object like all the other 
objects using new operator.

So Now I am lost again and I have no idea on how to possibly move 
forward. Frankly I don't feel confortable following the article Making 
Custom Components Accessible on the gnome developers wiki, it's why I 
have started exploring these things on my own hopefully asking more 
concrete questions. The only lesson I have learned so far is that I 
really need CustomCellRendererAccessible. But I don't have an idea on 
how to do that.

Thanks your patience and helpfull hints.


Greetings

Peter

On 07.07.2014 14:02, Piñeiro wrote:
> 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
>>
>> _______________________________________________
>> gnome-accessibility-list mailing list
>> [email protected]
>> https://mail.gnome.org/mailman/listinfo/gnome-accessibility-list

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