Certain terminal characters not rendering correctly

[ajkessel]

Windows Terminal version

1.18.230526002-preview

Windows build number

19045.2846

Other Software

mutt and neomutt use "alternate-character-set" characters to display thread and attachment trees. These characters, which are supposed to be lines and arrows, don't render correctly in Windows Terminal, as shown in the attached screenshot. I suspect there are other apps (maybe ncurses?) that will exhibit similar behavior. Is there a setting that will fix this, a font change, or is it an underlying bug?

Steps to reproduce

Open Windows Terminal with cygwin
Run mutt or neomutt

Expected Behavior

Visible lines/arrows

Actual Behavior

Aberrant characters

[zadjii-msft]

How do you have your cygwin profile configured/?

Can you share the output of locale?

[ajkessel]

LANG=
LC_CTYPE="en_US"
LC_NUMERIC="C.UTF-8"
LC_TIME="C.UTF-8"
LC_COLLATE="C.UTF-8"
LC_MONETARY="C.UTF-8"
LC_MESSAGES="C.UTF-8"
LC_ALL=

I just noticed if I use the powershell profile rather than the cygwin profile, the arrows render correctly. Will dig a bit and see if I can figure out what setting that is and report back, unless you have an idea/suggestion.

[ajkessel]

Oddly enough, if I ssh from a powershell profile tab to a Linux Box and run mutt, characters render correctly. If I run cygwin bash from the powershell profile tab first, characters render incorrectly.

Same result if I use windows cmd profile.

So it's only rendering incorrectly from within cygwin.

[ajkessel]

export TERM=linux

Fixes the issue. Is this a Windows Terminal problem, cygwin problem, mutt problem, or someting else?

[zadjii-msft]

This sounds a lot like #14982 (comment)

Does the commandline for your cygwin profile include -l -i/?

[ajkessel]

Does the commandline for your cygwin profile include -l -i/?

It didn't before, but I just tried adding it and it did not alter the behavior.

[ajkessel]

I took a look at that issue. term=linux and term=xterm both fix the rendering issue.

[elsaco]

@ajkessel the issue seems to be caused by the settings in .minttyrc. Look for the Locale, Charset and Term settings. Here's sample config I'm using:

$ cat .minttyrc
ThemeFile=nord
FontHeight=11
Locale=en_US
Charset=UTF-8
Columns=132
Rows=43
Scrollbar=none
Term=xterm-256color

Notice in your 2nd post how LANG= is not defined. I bet the Term is not defined either.

[ajkessel]

Yes, the issue was term. Setting it to something other than cygwin fixes the character rendering.

[DHowett]

Ah, thanks for following up!

Yes, TERM=cygwin engages a translation layer inside Cygwin that is only supposed to be used for old versions of Windows. Those older versions didn't support a lot of modern terminal features in the console, so Cygwin's translation layer is very limited.