Re: [Unified-im-api-devel] Re: [Uim] A proposal of unified input method C API.

[TOKUNAGA H. <tk...@xe...>]

Sorry for my late replying.

On Thu, 6 Jan 2005 08:44:33 +0800
Zhe Su <jam...@gm...> wrote:

>   Ok. I'll try to add surrounding text support in SCIM and Unified IM
> API. So could you please give me a proposal of the API? Is it enougth
> to implement it just like what gtk immodule does?

Unfortunately I don't have enough time to make a proposal for now. 

To tell the truth, I don't know so much about surrounding text, I can't
say GTK+ like surrounding text support is enough or not. Only I can say
is that it 'seems' enough for most users in the world.

But, for me, GTK+ like surrounding text supprt is not enough. If we
support surrounding text, I want to extend it a bit.

Following is my mail posted to uim's ML on last month. (It includes
some modification and complement.)


----------------------------------------------------------


Today, I want to write about uim's surrounding text support.

Currently, uim have no practical surrounding text support. Surrounding
text is need by some languages. For example, Thai input method needs
surrounding text. Of course, surrouding text is worth for CJK.

* GTK+ immodule

GTK+ provides 2 functions for input method. i.e. get_surrounding_text,
delete_surrounding_text. GTK+ doesn't support set/replace surrounding
text. But set/replace features are for text editing rather than for text
inputting, so that's not a critical problem.

GTK+'s spec is a bit confusing. If input method calls
gtk_im_context_get_surrounding, retrieve_context signal is emitted from
IM Context. Then text widget's callback function such as
'retrieve_context_cb' is called. This function is responsible for set
surrounding text via gtk_im_context_set_surrounding. i.e.
gtk_im_context_set_surrouding exists, but it's not for input method but
for text widget.


* Qt immodule

Qt immodule also probles get/delete surrounding text. There's no
set/replace support.


I propose 4 functions for uim's surrounding text support.

- get_surrounding(uim_context uc, char **text, int *cursor_pos)

- delete_surrounding(uim_context uc, int offset, int n_chars)

- set_surrounding(uim_context uc, const char* text, int cursor_pos)
This function set surrounding text to caret position. We may not need
set_surrouding if we have replace_surrounding.

- replace_surrounding(uim_context uc, int offset, int n_chars, 
                                                    char *text, char *cursor_pos)

This function delete surrounding, then set surrounding. I want to use
this for change surrounding text. Delete -> commit is not enough, it
should be atomic. Because if a user press undo button, the character
which he/she inputted would disappeared. That's confusing.

All of them are NOT for text widget, but for input method.


But, in this proposal, there are some problems. I want to list up them.

1. Could we get surrounding text in console?

  I don't know yet.

2. Implementation of replace/set surrounding is difficult.

  Should we consider the bridge which doesn't support replace/set
surrounding?

3. Replace surrounding is really need?

  I'm not confident in.


There may be further problems. Any comments are welcome.

Regards,

-- 
TOKUNAGA Hiroyuki
tk...@xe...
http://kodou.net/