Theme: CursorKind bar is using system terminal font color (can be effectively invisible)

[nuke-web3]

Summary

with any bar selection for a cursor, most evidently on the opposite of the OS/system theme, the bar is illegible:

[editor.cursor-shape]
insert = "bar"

Example in normal mode (catppuccin_latte):

insert mode (cursor just past as:

Reproduction Steps

Try out just about any theme, us a bar cursor, and I think it is using the underlying system color for terminal font to render, not some color from the theme...? In my case, wezterm using 'Monokai Dark (Gogh)'

Helix log

No response

Platform

Linux

Terminal Emulator

wezterm 20230712-072601-f4abf8fd

Helix Version

helix 23.05 (7f5940b)

[nuke-web3]

Confirmed - system term font color is used:

[the-mikedavis]

AFAIK there isn't a way for a terminal application to tell the terminal which color to use for the cursor. For block cursors we actually hide the terminal's cursor and highlight the cell at the cursor's position with the color from the theme. There isn't a way to highlight a part of a cell so we can't use the same trick for the bar cursor.

[nuke-web3]

I did a bit of poking, it seems that there may be a way based on nvim having a similar problem before:

• Support cursor colors alacritty/alacritty#826 (comment)
• tui: Use unibi_var_from_num when available neovim/neovim#7277
• https://github.com/mauke/unibilium/blob/master/doc/unibi_var_from_str.pod

Based on this perhaps #5319 is related to solving this... something to do with TERMINFO access?

[nuke-web3]

If using the system cursor isn't an option, is a hack possible to emulate the block cursor behavior with something that is close to a bar? Perhaps drawing over the cell with a unicode character that is "close enough" U+23C8 from https://en.wikipedia.org/wiki/Miscellaneous_Technical looks like perhaps one that could do that

[the-mikedavis]

Ah it looks like there are escape codes for setting this: https://github.com/wez/wezterm/blob/70931f58f1c7a57fd377f9862597e7b1fe070b52/docs/escape-sequences.md?plain=1#L396-L398 / https://github.com/alacritty/alacritty/blob/e29da339b4960b056b349f6bda172ca70d3c16a0/src/ansi.rs#L792-L803. I'm not sure how standard that sequence is but it seems like it has buy-in from popular terminal emulators. We could probably make use of that but first it would need to be contributed upstream to the terminal manipulation library we use: https://github.com/crossterm-rs/crossterm.

We can't use a unicode bar to do the same trick because we can't combine the bar with a character in that cell. So if there were any content in the same cell as the cursor we would need to choose between drawing the cursor and the content.

[getreu]

After setting

[editor.cursor-shape]
insert = "bar"

the theme gruber-darker has the same problem, while the theme autumn hasn't. I compared autumn.toml and gruber-darker.toml but I did not find out what difference causes the disappearance of the cursor.

BTW: I think this should be considered being a bug.

[getreu]

#9002 is related