Text misaligned when using Japanese input/IME on Windows with Windows Terminal

[ajantti]

When using IME, the typed text appears misaligned after the whole Input widget:

Sister issue to #5456, although clearly a different problem, in Windows Terminal this time. Looks a lot like what #3408 was trying to fix with the cursor position modification.

Textual Diagnostics

Versions

Name	Value
Textual	1.0.0
Rich	13.9.4

Python

Name	Value
Version	3.10.11
Implementation	CPython
Compiler	MSC v.1929 64 bit (AMD64)
Executable	C:\work\mkgtools\Tool\MKGConfluenceTool\venv\Scripts\python.exe

Operating System

Name	Value
System	Windows
Release	10
Version	10.0.19045

Terminal

Name	Value
Terminal Application	Windows Terminal
TERM	xterm
COLORTERM	Not set
FORCE_COLOR	Not set
NO_COLOR	Not set

Rich Console options

Name	Value
size	width=133, height=63
legacy_windows	False
min_width	1
max_width	133
is_terminal	True
encoding	utf-8
max_height	63
justify	None
overflow	None
no_wrap	False
highlight	None
markup	None
height	None

[github-actions]

We found the following entry in the FAQ which you may find helpful:

• Why doesn't Textual look good on macOS?

Feel free to close this issue if you found an answer in the FAQ. Otherwise, please give us a little time to review.

This is an automated reply, generated by FAQtory

[fancidev]

I can reproduce the issue with Windows 11 + Windows Terminal + Chinese IME.

The issue appears to be due to Windows Terminal's behavior. Specifically, if I comment out this line so that the terminal cursor is shown, then the IME pop-up would be placed at the insertion point correctly. (Well actually it is placed one cell after the insertion point, possibly due to Textual drawing the cursor manually.)

And it appears that when the terminal cursor is hidden, Windows Terminal places the insertion point at the end of line even though it should know the cursor position.

A potential fix is to rely on the terminal emulator's cursor instead of drawing it manually. I think this has some merit (e.g. the user could customize the cursor shape), but is probably complicated to make sure that the cursor doesn't appear when we don't want it to. So no easy fix I'm afraid...