[wayland-protocols] text-input: Add v3 of the text-input protocol

[Carlos Garnacho]

Hi!,

On Wed, Apr 11, 2018 at 8:52 PM, Weng Xuetian <wengxt at gmail.com> wrote:
> (forgot to reply to the list)
>
> On Wednesday, 11 April 2018 11:35:58 PDT Dorota Czaplejewicz wrote:
>> On Wed, 11 Apr 2018 11:26:22 -0700
>>
>> Weng Xuetian <wengxt at gmail.com> wrote:
>> > On Monday, 9 April 2018 07:20:53 PDT Dorota Czaplejewicz wrote:
>> > > On Sun, 11 Mar 2018 20:30:14 +0100
>> > >
>> > > Carlos Garnacho <carlosg at gnome.org> wrote:
>> > > > This new protocol description is a vast simplification over v2,
>> > > > highlights
>> > > > are:
>> > > > - All pre-edit text styling is gone, the protocol doesn't seem the
>> > > > place
>> > > >
>> > > >   to convey UI state. Clients are in better knowledge of how to make
>> > > >   the
>> > > >   pre-edit string distinguishable from regular text.
>> >
>> > As an long-time input method developer and CJK user, I'd prefer to keep
>> > the
>> > styling. In Chinese or Japanese, partially converted text are common and
>> > styling is useful to help user to distinguish which text is currently
>> > being
>> > converted. [1] But for the sake of in-app consistency, I'd say we don't
>> > need that much capability about styling though. Among all input methods
>> > supported by fcitx [2], only underline/highlight is being commonly used.
>> > Recently I started to use some strike style in only one single input
>> > method though, it can also be useful in certain cases.
>>
>> I think this use case is covered. For indicating what's currently being
>> changed, this protocol is using "preedit string". In GTK, the preedit text
>> is displayed with an underline, making is always clear what the suggestion
>> pertains to.
> I think you can take a closer look at [1].
>
> "葵あ" is the complete preedit text. The input method is converting "葵" and
> giving the candidates for it, the あ part is not yet handled by input method
> (but typed by user and appears in the preedit). That's why "葵" is being
> highlighted.

IIUC, is あ simply unhighlighted till handled by the IM (and the
suggestion menu changes accordingly)? do preedit text styles in other
fcitx IMs convey the same or different info?

I wonder if we are missing some on-the-wire state, rather than text
styling support per se. And given the can of worms styling brings in
(hard to know how to stand out from the IM side, a11y and color
blindness issues, ...), I would personally rather have a hint system
than let the IM meddle with a foreign UI.

>
> In a single CJK text composition, CJK people would type the full sentence
> ahead instead of word by word because this helps input method to understand
> the whole context and improve the prediction.

I'm no CJK expert, so this might not apply neatly, but note there is a
set_surrounding_text request to help IM get context outside the
preedit string. This may even be combined with
delete_surrounding_text+commit_string to alter text outside preedit,
too.

Cheers,
  Carlos