Background color not set correctly when also using underlines

[thwischm]

Hello everyone,

I ran into a bug with background color rendering when using kakoune inside ghostty. If you select a section that also has an underline, the selection sometimes becomes invisible. This happens with both normal and curly underlines. Not sure if this is a bug in ghostty or in kakoune, but it works correctly in kitty and gnome-console.

This is how it looks in kitty (with the selection rendering correctly):

This is how it looks in ghostty (selection invisible, even though the "ncl" part is selected):

These are the escape sequences that kakoune uses here:

echo -e "\033[;4:3;58:2::255:216:102m#\033[58:2::255:97:136mi\033[;4:3;1;38;2;255;255;255;48;2;51;51;51;58:2::255:97:136mn\033[;4:3;38;2;51;51;51;48;2;170;170;170;58:2::255:97:136mcl\033[m"

And the ghostty version:

Ghostty 1.1.3-main+870b74f4

Version
  - version: 1.1.3-main+870b74f4
  - channel: tip
Build Config
  - Zig version: 0.13.0
  - build mode : builtin.OptimizeMode.ReleaseFast
  - app runtime: apprt.Runtime.gtk
  - font engine: font.main.Backend.fontconfig_freetype
  - renderer   : renderer.OpenGL
  - libxev     : io_uring
  - desktop env: gnome
  - GTK version:
    build      : 4.16.12
    runtime    : 4.16.12
  - libadwaita : enabled
    build      : 1.6.4
    runtime    : 1.6.4
  - libX11     : enabled
  - libwayland : enabled

[mitchellh]

I'm unable to reproduce this. I tried on both macOS and Linux with your echo and selection kept the underlines and colors all correct. Is this perhaps a theme issue?

[00-kat]

Are you selecting using shift+hjkl in Kakoune, or selecting by shift-dragging across the screen with a mouse?

Edit: oh never mind, the reproduction you sent demonstrates that you're doing the former.

[00-kat]

I can reproduce this with a default config, on Linux with Ghostty 1.1.2-r148.gb5ecd7b-1-arch.

Kitty for comparision:

And Ptyxis:

For some reason Kitty doesn't draw the undercurl, Ghostty doesn't draw the background colour, and Ptyxis draws both…

[thwischm]

I narrowed it down to another example that's maybe more helpful:

echo -e "\033[4:3;38;2;51;51;51;48;2;170;170;170;58;2;255;97;136mset everything in one sequence, broken\033[m"
echo -e "\033[4:3;48;2;170;170;170;58;2;255;97;136monly set background, works\033[m"
echo -e "\033[38;2;51;51;51;48;2;170;170;170;58;2;255;97;136mno underline, works\033[m"
echo -e "\033[4:3;38;2;51;51;51m\033[48;2;170;170;170;58;2;255;97;136mtwo separate escape sequences, works\033[m"

When you try to set the underline type, background color, foreground color and underline color all in one sequence, ghostty draws none of them:

(Using the default config this time, to make sure it's not theme related. Sorry for earlier.)

Here's kitty for comparison, also default config:

[mitchellh]

Thanks, fixed in #5949

[thwischm]

Yep, kakoune works without any issues now. Thanks for the quick fix. And great work on the terminal!