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Bug 4782

Summary: IME_SendEditingEvent() always calls SDL_SendEditingText() with incorrect arguments
Product: SDL Reporter: tamo <ttakah+sdl>
Component: eventsAssignee: Sam Lantinga <slouken>
Status: NEW --- QA Contact: Sam Lantinga <slouken>
Severity: major    
Priority: P2    
Version: HG 2.0   
Hardware: All   
OS: Windows 10   
Attachments: not "end" but "length", and fix "start" and "length"
fix scope
fix it with correct indent
fix header and indent
picture of IME composition

Description tamo 2019-09-01 19:32:58 UTC 
First, see events/SDL_keyboard_c.h, line 56-57:

> /* Send editing text for selected range from start to end */
> extern int SDL_SendEditingText(const char *text, int start, int end);

But see video/windows/SDL_windowskeyboard.c, line 778:

>     SDL_SendEditingText(s, videodata->ime_cursor + (int)SDL_wcslen(videodata->ime_readingstring), 0);

The line should be:

>     SDL_SendEditingText(s, videodata->ime_cursor, (int)SDL_wcslen(videodata->ime_readingstring));

or

>     SDL_SendEditingText(s, len, (int)SDL_wcslen(videodata->ime_readingstring));

Otherwise, "start" and "end" are always incorrect.

--
Background: https://github.com/kivy/kivy/pull/6498
Comment 1 tamo 2019-09-01 20:02:50 UTC 
Oops, "end" should be "len+wcslen(reading)".

> SDL_SendEditingText(s, len, len + (int)SDL_wcslen(videodata->ime_readingstring));
Comment 2 tamo 2019-09-01 20:15:29 UTC 
No, reading events/SDL_keyboard.c and others, the last arg is not "end" but "length."
So events/SDL_keyboard.c is incorrect, too.
Comment 3 tamo 2019-09-01 20:24:24 UTC 
Created attachment 3940 [details]
not "end" but "length", and fix "start" and "length"

Fix both header and code
Comment 4 tamo 2019-09-01 20:30:22 UTC 
Created attachment 3941 [details]
fix scope

the previous patch didn't build
Comment 5 tamo 2019-09-01 20:32:21 UTC 
Created attachment 3942 [details]
fix it with correct indent

fix indent
Comment 6 tamo 2019-09-02 07:31:09 UTC 
Created attachment 3943 [details]
fix header and indent

The header is incorrect.
"readingstring" is just a pronunciation, not selection.

In fact, Japanese IMEs hardly use readingstring. (I've never imagined that.)
Comment 7 tamo 2019-09-02 07:42:42 UTC 
Created attachment 3944 [details]
picture of IME composition

What I really wanted are, things like GetCompositionTargetRange and GetImeTextSpans in https://github.com/chromium/chromium/blob/master/ui/base/ime/win/imm32_manager.cc code.

So, at least two numbers should be given to the event: target_start and target_end.

See the attached picure.
The red range is the "target" and the yellow spans are "clauses" in IME terms.
The target range is necessary for Japanese. (That's what I thought "readingstring" was.)

Anyway, that's another issue.