Writing Patterns

Patterns are the core of Gtheme’s theming system. This guide walks you through creating a pattern from an existing configuration file.

Step by step

Let’s say you want to theme your kitty terminal. Here’s how to turn a static config into a Gtheme pattern.

Start with the original config

Take the color-related section of your config file. For kitty, that might be:
```
foreground #f8f8f2
background #1e1f28
color0 #000000
color1 #ff5555
```
Replace hardcoded colors with placeholders

Swap each hex value with the corresponding Gtheme variable:
```
foreground #<[foreground]>
background #<[background]>
color0 #<[black]>
color1 #<[red]>
```
Add the output-file directive

Add a line at the very top specifying where the filled file should be written:
```
<[output-file]>=~/.config/kitty/colors.conf
```
Add user settings with fallbacks (optional)

For values that vary per user (like fonts), use user settings with a fallback:
```
font_family <[default-font|JetBrains Mono]>
font_size <[default-font-size|12]>
```
Save the pattern

Save the file as kitty.pattern in your desktop’s gtheme/patterns/ directory.
Enable it

Add "kitty": true to the actived section of desktop_config.json, or run:
Terminal window
```
gtheme pattern enable kitty
```
Test it
Terminal window
```
gtheme theme apply Dracula
```
Check that ~/.config/kitty/colors.conf was generated with the Dracula colors.

Real-world examples

CSS colors (Waybar)

For CSS-based configs, you might generate CSS custom properties:

<[output-file]>=~/.config/waybar/colors/colors.css
@define-color background #<[background]>;
@define-color on_background #<[foreground]>;
@define-color primary #<[blue]>;
@define-color secondary #<[cyan]>;
@define-color error #<[red]>;

Hyprland variables

For Hyprland, colors use the rgba() format:

<[output-file]>=~/.config/hypr/colors/colors.conf
$primary = rgba(<[blue]>ff)
$on_primary = rgba(<[background]>ff)
$surface = rgba(<[background]>ff)
$on_surface = rgba(<[foreground]>ff)

Rasi format (Rofi)

<[output-file]>=~/.config/rofi/colors.rasi
* {
    primary: #<[blue]>;
    surface: #<[background]>;
    on-surface: #<[foreground]>;
}

Adding a post-script

If the application doesn’t auto-reload when its config changes, create a post-script with the same name. For kitty:

#!/bin/bash
pkill -USR1 kitty
exit 0

Make it executable:

chmod +x gtheme/post-scripts/kitty.sh

Pattern modules

For applications with multiple config files (like Spotify with Spicetify), create a directory:

patterns/
└── spotify/
    ├── spotify-colors.pattern
    └── spotify-theme.pattern

The module name is spotify. Enabling/disabling it affects both sub-patterns.

Tips

Check existing patterns — browse the gtheme-desktops repository for real examples.
Only template what changes — don’t put your entire config in a pattern. Only include the color-related portions. Use @import, source, or include directives in the main config to pull in the generated color file.
Use comments — add <[theme-name]> in a comment at the top so you can tell which theme generated the file.
Test with contrasting themes — try a light theme (like One-Light) and a dark theme (like Dracula) to make sure your pattern works well with both.