Re: [A12n-Collab] Combining diacritics, type them as if they were dead keys? (GTK+, X.Org)

[Simos Xenitellis <simos.lists@xxxxxxxxxxxxxx>]

Hi Andrew,

O/H Andrew Cunningham έγραψε:
> Hi Simos,
>
> Simos Xenitellis wrote:
>
> > Hi All,
> >
> > At the moment, when one types combining diacritics in X.Org (as in 
> > Linux), they type
> > <letter> <combining diacritic 1> <combining diacritic 2> ...
> which is direct logical input which normally produces the output: 
> <base character> <combining diacritic one> <combining diacritic 2> ...
That is right.
> > This is different from the case when you have dead keys:
> >
> > <dead key 1> <dead key 2> ... <letter>
> which on simple keyboard layouts (xkb, win32 keyboard model) produces 
> the output <precomposed character>
> > There has been interest by users to be able to type in the order:
> >
> > <combining diacritic> <letter>
> >
> > or, in the general case,
> >
> > <combining diacritic 1> <combining diacritic 2> ... <letter>
> so you are suggesting that
>
> <combining diacritic 1> <combining diacritic 2> ... <letter>  produces 
> <precomposed character>
> which is just a normal dead key system
>
> or are you suggesting
>
> <combining diacritic 1> <combining diacritic 2> ... <letter>  
> produces  <base character> <combining diacritic one> <combining 
> diacritic 2> ...
> which would mean the input system would need to be able to handle 
> sequence checking, normalisation, character reordering, so basically 
> you're suggesting a smart input system rather than the xkb model, so 
> something like SCIM+KMFL? or similar?
(I am referring to having the XKB layouts/compose sequences revamped so 
that users will be able to type the base character last in the sequence. 
I am not referring to systems like SCIM, KMFL, etc).
I am referring to the cases that no precomposed characters exist, 
therefore the output would have to be "<base character> <combining 
diacritic one> <combining diacritic 2> ...", and what I suggest is
<combining diacritic 1> <combining diacritic 2> ... <letter>  produces  
<base character> <combining diacritic one> <combining diacritic 2> ...
Perhaps this would have been clearer if I had written from the start 
that letter=base character.
Compose sequences with dead keys, which produce precomposed characters, 
remain as there have been. For example,
<dead_acute> <a> : á  (precomposed)

The idea here is to add compose sequences such as

<combining_acute> <t> : t́  (not precomposed; I use 't' as a made-up example)

In technical terms, it is possible to add compose sequences in Xorg that 
produce more than one character (base-character, combining-diacritic-1, 
combinding-diacritic-2, ...).
Such compose sequences do not exist yet, though it is possible to add.
We would not have to do any additional coding, but just update the XKB 
layouts and compose sequences.
In addition, it is also possible to get GTK+ support such compose 
sequences as well.
The reason why we would consider updating our XKB layouts to support the 
order that the base character is typed at the end in compose sequences, 
is to make it easier and more usable for the users.
Now, whether it actually makes it easier for the users is an issue for 
debate.
I do not know, and this is something I am asking.
> what other features would such a keyboard system have? 
As we would be updating the layouts and more importantly the compose 
sequences, there are no new features per sé.
> > Is there interest to go for this case where the letter is typed last?
> > It would be good to get some input on this, because if we go for it, 
> > it would affect all layouts.
> yes and no
>
> you'd have to have multiple layouts, assuming the project builds for 
> xkb and win32 keyboard model (using MSKLC).
I am not familiar with how MSKLC behaves when using combining 
diacritics. How does it respond when compose sequences with combining 
diacritics require the base character typed at the end?
Simos