Italic text is rendered incorrectly and looks weird

[zhang-stephen]

Windows Terminal version

1.16.2641.0

Windows build number

windows 21H2 enterprise 19044.1889

Other Software

• GNU bash 4.2.46(2)-release, x86_64-redhat-linux-gnu
• tmux 3.1a, with $TERM=xterm-256color
• CentOS 7.9 x64, login by openSSH integrated in windows
• Font: FiraCode NF Retina with NERD font patch.

Steps to reproduce

login the CentOS, and run tmux, then run these following commands:

echo -e "ABCDEFGHIJKLMNOPQRSTUVWXYZ \e[3mABCDEFGHIJKLMNOPQRSTUVWXYZ\e[0m"
echo -e "abcdefghijklmnopqrstuvwxyz \e[3mabcdefghijklmnopqrstuvwxyz\e[0m"
echo -e "0123456789,./<>?;'[]:{}-=_+*&^%$#@!()| \e[3m0123456789,./<>?;'[]:{}-=_+*&^%$#@!()|\e[0m"

The configuration for the SSH session:

{
    "adjustIndistinguishableColors": "indexed",
    "antialiasingMode": "grayscale",
    "backgroundImage": null,
    "closeOnExit": "always",
    "colorScheme": "Campbell",
    "commandline": "ssh p8zhang@<host>",
    "cursorShape": "underscore",
    "font":
    {
        "face": "FiraCode NF Retina",
        "size": 11.0
    },
    "guid": "{6c5275a4-b63e-46ce-a2eb-e3ea1f73666f}",
    "hidden": false,
    "historySize": 100001,
    "intenseTextStyle": "bright",
    "opacity": 85,
    "padding": "8",
    "useAcrylic": true,
    "useAtlasEngine": true
}

I guessed this issue is related to the new Atlas Engine, but there would be nothing changed if I turned off it.

Expected Behavior

No response

Actual Behavior

You will get these WEIRD italics:

And this issue could be reproduced in the PowerShell 7.2.6, with the almost same configuration of the SSH session.
Just run "$($PSStyle.italic)ABCDEFGHIJKLMNOPQRSTUVWXYZ", you will got the similar result:

[zhang-stephen]

I think it's an issue introduced by new Atlas Engine now... The renderer works well with reopening the session after new engine disabled.

[lhecker]

Yep we know about this issue. This happens because we don't support glyphs that are too wide to fit into their cells. For instance the "A" character is 1 cell wide. But a italic "A" character is about 1.2 cells wide and so it gets shrinked down. This primarily happens with Nerd Fonts because it doesn't ship italic variations with their fonts.
I'm currently working on a general solution.