Dotted and dashed underlines are sometimes too thin

[sergei-grechanik]

Dotted and dashed underlines are rendered thinner than normal underlines, sometimes so thin that they disappear completely. I observe this bug when running kitty like this:

kitty -c NONE -o font_family="Liberation Mono" -o font_size=5

My dpi settings:

Xft.dpi:        168

Cat the following file to reproduce:
underline-test.txt

Screenshot:

When increasing the font size, it looks fine:

Environment details

kitty 0.37.0 (143705f2a7) created by Kovid Goyal
Linux sgrechanik-lenovo 6.8.0-40-generic #40-Ubuntu SMP PREEMPT_DYNAMIC Fri Jul  5 10:34:03 UTC 2024 x86_64
Ubuntu 24.04 LTS sgrechanik-lenovo /dev/tty

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=24.04
DISTRIB_CODENAME=noble
DISTRIB_DESCRIPTION="Ubuntu 24.04 LTS"
Running under: X11
OpenGL: '4.6 (Core Profile) Mesa 24.0.9-0ubuntu0.1' Detected version: 4.6
Frozen: False
Fonts:
  medium: LiberationMono: /usr/share/fonts/truetype/liberation/LiberationMono-Regular.ttf:0
          Features: ()
    bold: LiberationMono-Bold: /usr/share/fonts/truetype/liberation/LiberationMono-Bold.ttf:0
          Features: ()
  italic: LiberationMono-Italic: /usr/share/fonts/truetype/liberation/LiberationMono-Italic.ttf:0
          Features: ()
      bi: LiberationMono-BoldItalic: /usr/share/fonts/truetype/liberation/LiberationMono-BoldItalic.ttf:0
          Features: ()
Paths:
  kitty: /home/sgrechanik/proj/kitty/kitty/launcher/kitty
  base dir: /home/sgrechanik/proj/kitty
  extensions dir: /home/sgrechanik/proj/kitty/kitty
  system shell: /bin/bash
System color scheme: light. Applied color theme type: none
Loaded config overrides:
  font_family Liberation Mono
  font_size 5

Config options different from defaults:
font_family Liberation Mono
font_size   5.0

Important environment variables seen by the kitty process:
	PATH                                <omitted>
	LANG                                en_US.UTF-8
	EDITOR                              vim
	SHELL                               /bin/bash
	DISPLAY                             :0
	USER                                sgrechanik
	XCURSOR_SIZE                        32
	XDG_CONFIG_DIRS                     /home/sgrechanik/.config/kdedefaults:/etc/xdg/xdg-plasma:/etc/xdg
	LC_ADDRESS                          en_US.UTF-8
	LC_NAME                             en_US.UTF-8
	LC_MONETARY                         en_US.UTF-8
	XDG_SEAT                            seat0
	XDG_SESSION_DESKTOP                 plasma
	XDG_SESSION_TYPE                    x11
	LC_PAPER                            POSIX
	XDG_CURRENT_DESKTOP                 KDE
	XDG_SESSION_CLASS                   user
	LC_IDENTIFICATION                   en_US.UTF-8
	LC_TELEPHONE                        en_US.UTF-8
	LC_MESSAGES                         en_US.UTF-8
	LC_MEASUREMENT                      POSIX
	XDG_VTNR                            2
	XDG_SESSION_ID                      2
	LC_CTYPE                            en_US.UTF-8
	XDG_RUNTIME_DIR                     /run/user/1000
	LC_TIME                             C
	LC_ALL                              
	LC_COLLATE                          en_US.UTF-8
	XDG_DATA_DIRS                       /usr/share/plasma:/usr/share/gnome:/usr/local/share/:/usr/share/:/var/lib/snapd/desktop
	LC_NUMERIC                          en_US.UTF-8