RFR: 8368478: RichTextArea: add IME support [v2]

[Alexander Zuev]

On Wed, 29 Oct 2025 18:12:36 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> Adds Input Method Editor (IME) support to `RichTextArea`/`CodeArea`.
>> 
>> Tested on macOS and Windows 11 with Japanese and Chinese (pinyin) input methods.
>> Please test this on Linux, even though there is no platform-specific code in this PR (should work the same way it does in `TextArea`/`TextField`)
>> 
>> For testing, one can use the updated Monkey Tester
>> https://github.com/andy-goryachev-oracle/MonkeyTest
>> (optionally enable IME events in stdout with Logging -> IME Monitor)
>
> Andy Goryachev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 11 additional commits since the last revision:
> 
>  - review comments
>  - Merge branch 'master' into 8368478.ime
>  - test
>  - accessor
>  - cleanup
>  - whitespace
>  - Merge remote-tracking branch 'origin/master' into 8368478.ime
>  - ime object
>  - ime location
>  - ime works
>  - ... and 1 more: https://git.openjdk.org/jfx/compare/0a8ae3be...3bb8d850

Marked as reviewed by kizune (Committer).

I have tested couple of input methods including Japanese (Mozc) in different modes. In general the input method works and i was able to do the typing reasonably well but the editing sometimes leaves strange artifacts - especially when cancelling the suggestion - there is an underline text that was a raw input before suggestions and if you delete this text the underline stays but you can't navigate to that place as if there is no text but when window loses focus the raw input symbols re-appear in this place.

Also whenever i am trying to commit a suggestion the following warning pops in the terminal where i started the application:

(java:4993): IBUS-WARNING **: 15:31:22.791: ibus_input_context_post_process_key_event: Type 'h' is not supported.

Not sure what it is about.
I recorded the video that demonstrates the issue with the cancelled input but i do not think that this is a blocker for the feature.
[Screencast from 2025-10-30 15-31-14.webm](https://github.com/user-attachments/assets/ad7fff10-181b-48b9-9074-30496dd9e71e)

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PR Review: https://git.openjdk.org/jfx/pull/1938#pullrequestreview-3401892121
PR Comment: https://git.openjdk.org/jfx/pull/1938#issuecomment-3470500292