[g-a-devel]Re: Why Can't I use BRLTTY With Gnopernicus

["John J. Boyer" <director chpi org>]

Mario,

Thanks for your explanation. I just discovered most of this myself a few 
minutes ago. The thing that is causing me trouble is that keyboard 
emulation no longer works. It did right after you wrote ttybrl.c . I could 
pressd the down arrow key combination on my braille keyboard and Gnome 
would do a down-arrow. If I was in a text box I could type a character on 
the braille keyboard and it would appear on the screen. looking at the 
source code for ttybrl.c I can see that it is trying to send keycodes that 
have not been mapped somewhere. However, they are not getting a response. 
My gues now is that something has changed in Gnome and the keycodes need 
to be encoded differently. I have already informed Dave Mielke of this 
problem.

John
 On Tue, 23 Sep 2003, Mario Lang wrote:

> "John J. Boyer" <director chpi org> writes:
> 
> > So far it looks like brltty is the more likely, because everytime I press a
> > key on my braille keyboard, except for a few, there is a message on the tty
> > where I invoked startx that says "Default: sending DKxxxx".
> 
> This message is produced whenever the ttybrl module receives
> a keycode which is not yet mapped to a corresponding Gnopernicus braille
> keycode. Quoting brltty-3.3.1/Documentation/README.Gnopernicus, the
> following table lists BRLTTY keypresses and their corresponding Gnopernicus 
> actions.
> 
>    Command      Binding      Description
>    ----------   -----------  -----------
>    CMD_LNUP     DK00         Go To Parent
>    CMD_HOME     DK01         Go To Focus
>    CMD_LNDN     DK02         Go To Child
>    CMD_FWINLT   DK03         Go To Previous
>                 DK04         Repeat Last
>    CMD_FWINRT   DK05         Go To Next
>                 DK01DK02     Do Default Action
>    CR_ROUTE     HMSnn        Route Cursor
> 
> Note that "Repeat Last" and "Do Default" are currently not mapped, because
> we couldn't think of a really good keycode for them.
> 
> So, what should work for you is moving left/right and up/down in the
> widget hierarchy.  Cursour routing keys, if you have some, should also work.
> Everything else is just a question of filling out the case statement
> in gnopernicu/braille/libbrl/ttybrl.c in function brltty_brl_glib_cb
> to make the corresponding brltty keycodes to Gnopernicus braille keyboard codes.
> 
> However, note that this does not really prevent you from using Gnopernicus,
> since all the navigation functions are mapped on the computer keypad anyway.
> 
> Note that the reason for the small number of mappings is mainly due to
> the small number of default braille key to function bindings in Gnopernicus.
> At the time I wrote ttybrl.c, the keycombinations listed above were the only
> ones defined in Gnopernicus.  It would not have made much sense to
> create more mappings, since they wouldn't have invoked anything anyway.
> 
> If Braille display support in Gnopernicus increases in flexibility,
> it is very easy to add more mappings to ttybrl.c.
> 
> 

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