[Bug]: incorrect CJK characters input

[knyipab]

Problem description

@twaik Shall we continue here the discussion of CJK character issues initiated in #620 .

I tested with the lastest Termux:X11 build and found issues pasting CJK characters using Samsung keyboard. ANd I also tested tigervnc + RealVNC Viewer for comparison. I found that:

• Termux:x11 has different behaviors across applications. code-oss and chromium see incorrect random re-occurrence of characters, while mousepad is robust in handling the key events.
• In tigervnc + RealVNC Viewer, CJK input is very consistent across applications. Its major problem is not sending specific character codes at all (see also its xev log). I don't quite know of other mainstream Android vnc viewer that supports CJK keyboard input, so can't be certain the cause is from RealVNC or tigervnc.
• I have no expertise but I feel that this issue is fixable given the test result below. It might be more helpful comparing x11-zh-sc.log and vnc-zh-sc.log.

Termux-X11

	JP	ZH (trad.)	ZH (simp.)	KR
input	入力方法が正常かどうかをテストする	測試輸入法是否正常	测试输入法是否正常	입력 방법이 정상인지 테스트
mousepad	入力方法が正常かどうかをテストする	測試輸入法是否正常	测试输入法是否正常	입력 방법이 정상인지 테스트
code-oss	入力方法が正常正どうかをテがトする をテ方トす正常かどうかが正スかする	測試輸入正是否正輸 測法輸入法是測試常	测试是否法是测正常 测试是入法是测正常	입력 방법이 정상인지 테이트 입력 방법스 트상력지 법스정
chromium	入力方法が正常かどうか方テスかする をテス法が正入かどうかを正スかどる	測試輸否正是否正常 入試輸入法是否正輸	测试输入正常否正输 测法输入法常测正常	입력 방테이 정입력지 테스정 입인 방법이 정상력지 법이트
xev	x11-jp.log	x11-zh-tc.log	x11-zh-sc.log	x11-kr.log

tigervnc + RealVNC Viewer

	JP	ZH (trad.)	ZH (simp.)	KR
input	入力方法が正常かどうかをテストする	測試輸入法是否正常	测试输入法是否正常	입력 방법이 정상인지 테스트
mousepad	入力方法が正常かか	入法是否正常	测试输入法是否正常
code-oss	入力方法が正常かか	入法是否正常	测试输入法是否正常
chromium	入力方法が正常かか	入法是否正常	测试输入法是否正常
xev	vnc-jp.log	vnc-zh-tc.log	vnc-zh-sc.log	vnc-kr.log

What steps will reproduce the bug?

You may debug by using Samsung keyboard to paste CJK character string from any translation app such as Google Translate.

What is the expected behavior?

No response

[twaik]

I am aware about the problem. But the code I used for handling raw Unicode was borrowed from tigervnc and improved a little with suggestions of some other contributors. I simply have no idea what I can do. I opened 2 issues in tigervnc project but currently they did not commit fixes.