GTK and Qt Applications

This guide covers theming applications built with GTK, Qt, and KDE Plasma toolkits.

GTK 3/4 Applications

GTK applications include most GNOME apps and many Linux applications. Noctalia can automatically theme them using the adw-gtk3 theme.

Setup

1. Install required packages:

   # Arch Linux / Manjaro
   paru -S adw-gtk-theme nwg-look
   
   # Other distributions
   # Install adw-gtk-theme and nwg-look from your package manager

2. Apply the GTK theme:

   • Using nwg-look (recommended):

     • Open nwg-look
     • Select adw-gtk3 from the theme list
     • Click “Apply”
     • 

   • Using command line:

     gsettings set org.gnome.desktop.interface gtk-theme 'adw-gtk3'

3. Enable GTK theming in Noctalia:

   • Open Settings → Color Scheme → Templates
   • Toggle on GTK

Troubleshooting

• Theme not applying: Completely restart GTK applications (close and reopen)
• Some apps still look wrong: Some GTK apps may need GTK 4 theme separately:

  gsettings set org.gnome.desktop.interface gtk-theme 'adw-gtk3'
  gsettings set org.gnome.desktop.interface color-scheme 'prefer-dark'  # or 'prefer-light'

• Flatpak apps: Flatpak apps may need the theme installed in their sandbox:

  flatpak install org.gtk.Gtk3theme.adw-gtk3-dark
  flatpak install org.gtk.Gtk3theme.adw-gtk3

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Qt Applications

Qt applications include KDE apps and many cross-platform applications. Noctalia themes them through qt6ct.

Setup

1. Install qt6ct:

   # Arch Linux / Manjaro
   paru -S qt6ct
   
   # Other distributions
   # Install qt6ct from your package manager

2. Set environment variable: Add this to your window manager configuration or shell profile:

   For Niri (config.kdl):

   environment {
     QT_QPA_PLATFORMTHEME "qt6ct"
   }

   For Hyprland (hyprland.conf):

   env = QT_QPA_PLATFORMTHEME,qt6ct

   For Sway (config):

   setenv QT_QPA_PLATFORMTHEME qt6ct

   For shell profile (~/.bashrc or ~/.zshrc):

   export QT_QPA_PLATFORMTHEME=qt6ct

3. Enable Qt theming in Noctalia:

   • Open Settings → Color Scheme → Templates
   • Toggle on Qt

4. Configure qt6ct:

   • Run qt6ct from terminal
   • Go to Color Scheme tab
   • Select noctalia from the dropdown
   • Click Apply and OK

Troubleshooting

• Qt apps not themed: Ensure the environment variable is set before launching applications
• qt6ct not found: Make sure qt6ct is installed and in your PATH
• Theme not updating: Restart Qt applications after changing color schemes

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KDE Plasma (KColorScheme)

If you’re using KDE Plasma, Noctalia can apply colors through the native KColorScheme system.

Setup

1. Enable KColorScheme in Noctalia:

   • Open Settings → Color Scheme → Templates
   • Toggle on KColorScheme

2. Apply in KDE System Settings:

   • Open System Settings → Appearance → Colors
   • Select the noctalia color scheme
   • The scheme will update automatically when you change colors in Noctalia

Troubleshooting

• Scheme not appearing: Restart KDE Plasma or log out and back in
• Colors not updating: Ensure KColorScheme toggle is enabled in Noctalia settings