Re: [orca-list] Tabs with brltty and orca

[Michael Whapples <mwhapples aim com>]

I will try and explain this, and I believe it is a brltty and orca
issue.

All characters in a computer have a unique value, and it is up to the
computer (operating system or any other software controlling the output
devices) to decide how these should be displayed. In a text console, I
believe it expands tabs for the display (enters the number of spaces
needed to make the correct indentation) and for nano I guess that orca
is getting this expanded tab (nano understands it as a tab character,
that is why when backspacing a tab in nano it only takes one press to
remove it). 

For gedit (or other GUI apps such as eclipse), orca is interacting with
the app, not a console (display system) so recieves the tab character
itself. Orca could expand the tab (I think the windows based screen
readers do), but orca doesn't and passes the tab character to brltty.
Brltty might be able to expand the tab as well, but the table for nabcc
(/etc/brltty/text.nabcc.tbl which probably is the table you are using)
defines tab as dots 2 4 7 and 8. You will find other characters which
bring up strange braille symbols (the carrage return character, used by
windows as part of the new line marker displays dots 1 3 4 7 and 8).
Infact this behaviour isn't entirely unique to orca and linux, the linux
new line character (typically \n in programming or value 0x0A in hex)
when viewed in notepad by window-eyes appears in braille as dots 2 4 5 7
and 8.

To state it shortly, something needs to process the tab characters,
console apps have the console doing this, but GUI apps miss that middle
step out and communicate direct with orca and so nothing changes them to
multiple spaces.

Now how to resolve this. Either orca needs modifying which should be
possible but requires programming skills, or alter the brltty table
although I am unsure if brltty supports mapping a single character to
multiple braille cells.

Hope this helps you understand why and what might be done about it.

From
Michael Whapples