IME: TextEdit widget cannot support CompositionEnd only input character

[FrankLeeC]

Describe the bug
Can not input CompositionEnd character directly into TextEditor.
when input no-latin character such as Chinese into TextEditor, i must first input some word to trigger CompositionStart/CompositionUpdate event, then input some mark to trigger CompositionEnd event.
if i just want to type in a single character that trigger CompositionEnd event, TextEditor won't insert this character to text.

To Reproduce
1.Setup a demo app containing a TextEdit
2.Use Chinese PinYin input.
3.Do not type in any other word, just press [shift+1] , [shift+6] , [,], [.], [?] or any other CompositionEnd character.
4.Nothing typed into TextEdit

Expected behavior
Expected to type in Chinese character directly such as ！……，。《》、【】without need to trigger CompositionStart/CompositionUpdate event.

Desktop (please complete the following information):
 - OS: Windows11 Naive
 - Browser Naive App
 - Version 0.24.1 and master branch

/crates/egui/src/widgets/text_edit/builder.rs L1061.
if prediction != "\n" && prediction != "\r" && state.has_ime
this line ensure that i cannot input any CompositionEnd character unless input something to trigger CompositionStart to make has_ime as true.
tried to modify this line to
if prediction != "\n" && prediction != "\r"
if don't ensure has_ime be true, input CompositionEnd character directly successfully. Also, following some CompositionStart/CompositionUpdate character works too.

[emilk]

Can you check if window.set_ime_allowed is called at the correct time in crates/egui-winit/src/lib.rs?

[FrankLeeC]

Can you check if window.set_ime_allowed is called at the correct time in crates/egui-winit/src/lib.rs?

add log after L731(if self.allow_ime != allow_ime) in crates/egui-winit/src/lib.rs
when mouse focus in textedit, window.set_ime_allowed is called, allow_time is true and self.allow_time is false.
when mouse focus outside textedit,
called again, allow_time is false and self.allow_time is true.

[emilk]

Ok, so that at least seems to work.

So as far as I understand you, you see CompositionEnd events with the correct characters (！ etc), and though the TextEdit has focus and set_ime_allowed(true), the characters don't show up in the TextEdit field?

It looks to me the use of state.has_ime in crates/egui/src/widgets/text_edit/builder.rs may be wrong.

Since you seem to know how IME should work (I don't 😅), could you please take a look, and perhaps make a PR if you figure out a fix? 🙏

[FrankLeeC]

Ok, so that at least seems to work.

So as far as I understand you, you see CompositionEnd events with the correct characters (！ etc), and though the TextEdit has focus and set_ime_allowed(true), the characters don't show up in the TextEdit field?

It looks to me the use of state.has_ime in crates/egui/src/widgets/text_edit/builder.rs may be wrong.

Since you seem to know how IME should work (I don't 😅), could you please take a look, and perhaps make a PR if you figure out a fix? 🙏

Thank you for your help. I'll make a PR later.😀

[FrankLeeC]

Here is a PR for this bugfix. #3768