RFR: 8368478: RichTextArea: add IME support

[Lukasz Kostyra]

On Fri, 24 Oct 2025 14:16:02 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

> I am curious: could you tell me more about Polish/Spanish IME, what exactly have you try?

As for Spanish, the method I use is to press `'` key and then `e` key, that triggers an IME shortcut to input `é`. For Polish there is a few key combinations to get the diacritics, but since Poland most commonly uses the US keyboard layout its not always IME-dependent - I like to check them regardless though. The combos for Polish are Right Alt + A/C/E/L/N/O/X/Z - should produce ą/ć/ę/ł/ń/ó/ź/ż respectively. Note that these combos work only in layout sometimes (ex. on Windows) called "Polish (Programmers)", There's an older layout "Polish (214)" that dates all the way back to the typewriter era, but it's now considered obsolete and almost everyone uses the former.

One more IME check I also do borrows from [this old commit replacing XIM with IBus](https://github.com/openjdk/jfx/pull/1080#discussion_r1885813314) and refers to Chinese (Pinyin) keyboard layout, simply trying to type "ni hao" - without IME this produces that exact text using latin alphabet, while with properly working IME it gets converted to respective Chinese characters.

In case of RTA, without this change Polish diacritics worked fine, but Spanish ones did not and Chinese keyboard produced latin characters. This change makes both the Spanish shortcut and Chinese character conversion work properly.

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PR Comment: https://git.openjdk.org/jfx/pull/1938#issuecomment-3450395279