Hellwal - Fast, Extensible Color Palette Generator

<p align="center"> <img src="https://raw.githubusercontent.com/danihek/trashcan/refs/heads/main/output.gif" alt="Preview of color palettes generated by hellwal" width="500" > </p>

Star History

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Installation

1. Archlinux:

yay -S hellwal

2. Mac/Linux via Homebrew:

brew install hellwal

3. NixOS, nixpkgs unstable:

environment.systemPackages = [
  pkgs.hellwal
];

Building

Clone git repo, run make command and you are ready to go! - you just need a C compiler and gnumake!

git clone https://github.com/danihek/hellwal && cd hellwal && make

How to use?

Run this with your wallpaper image:

hellwal -i [image]

You can also randomly pick an image from a given directory like this:

hellwal -i <folder> --random

Generated templates are saved in ~/.cache/hellwal/.

Templates

[INFO] - if you got hellwal from the AUR, examples of default templates can be found in /usr/share/docs/.

There are also examples in the templates folder. They look more-less like this:

# Main
background='%%background%%'
foreground='%%foreground%%'

# Path
wallpaper_path='%%wallpaper%%'

# Colors
color0='%%color0.hex%%'
color1='%%color1.hex%%'

# ... and so on and so forth.

color15='%%color15.hex%%'


# RGB
backgroundRGB='%%background.rgb%%'
foregroundRGB='%%foreground.rgb%%'

color15butRGB='%%color15.rgb%%'

You can get any generated color for values 0 to 15.

After the color keyword, you can specify the format: hex, rgb, or a single rgb channel. By default, the template output is in hex.

Available color template formats:

| Type | Input | Output | | ---- | ---------- | ------- | | hex | color0.hex | 000000 | | rgb | color0.rgb | 0, 0, 0 | | r | color0.r | 0 | | g | color0.g | 0 | | b | color0.b | 0 |

Additional variables accepted by templates

Alongside colors, you can specify some variables to make them more suitable for your needs. For now these variables are available:

| Variable | Description | Usage | | -------- | ---------------------- | ---------------------------- | | alpha | Set transparency value | %% color1.hex alpha=0.5 %% |

alpha is ignored for single rgb channels.

JSON

You can use the --json argument to suppress any other output and write colors to stdout in JSON format. You can then manipulate the output with jq. For example:

hellwal -i [wallpaper] --json | jq '.'

Themes

You can set your own theme, re-run it anytime and apply it to your config or other programs! It can be a previously generated palette from an image, gruvbox, Tokyo Night, or anything you want! For example, gruvbox theme:

%% color0  = #282828 %%
%% color1  = #cc241d %%
%% color2  = #98971a %%
%% color3  = #d79921 %%
%% color4  = #458588 %%
%% color5  = #b16286 %%
%% color6  = #689d6a %%
%% color7  = #a89984 %%
%% color8  = #928374 %%
%% color9  = #fb4934 %%
%% color10 = #b8bb26 %%
%% color11 = #fabd2f %%
%% color12 = #83a598 %%
%% color13 = #d3869b %%
%% color14 = #8ec07c %%
%% color15 = #ebdbb2 %%

Save the text above as a file or copy gruvbox from this repo and just run hellwal:

hellwal --theme ./themes/gruvbox.hellwal

I recommend putting all themes in the default theme folder ~/.config/hellwal/themes. This way, you can provide the theme name without specifying the path, and hellwal will pick it up automatically. Of course if you want, you can also set a different theme folder. For example:

hellwal -t gruvbox.hellwal --theme-folder ~/dotfiles/configs/hellwal/themes

NEON Mode

Neon mode boosts colors to make them look more vibrant and bold. Sometimes it's a pain in the EYE, but it often looks better. Turned off by default.

hellwal -i [wallpaper] --neon-mode

Modes

You can select -d/--dark or -l/--light mode on any given image, theme, etc., no matter if it's generated from an image or from a theme file. There is also --color mode.

Dark mode (on by default)

hellwal -i [wallpaper] --dark

Light mode

hellwal -i [wallpaper] --light

color mode (crazyy one)

hellwal -i [wallpaper] --color

The best thing about it is that you are able to combine all of these together. Usually it's not a good idea, but sometimes you can achieve some crazy color combinations!

hellwal -i [wallpaper] --color --light --dark

---

Also, you have a couple of cool arguments to manipulate how colors will be computed:

• you can darken all colors by specifying --dark-offset from 0-1 (the higher the value, the darker the colors):

hellwal -i [wallpaper] --light --dark-offset 0.5

• same with --bright-offset (the higher the value, the brighter the colors):

hellwal -i [wallpaper] --bright-offset 0.5

• invert colors with --invert:

hellwal -i [wallpaper] --light --invert

• specify grayscale, if you want monochromatic colors, with --gray-scale:

hellwal -i [wallpaper] --color --gray-scale 0.8

• ensure colors are readable against the background with --check-contrast:

hellwal -i [wallpaper] --check-contrast

Scripts

With --script or -s you can run a script (or any shell command) after hellwal.

Note: it will only run if hellwal does not encounter any errors.

On a side note:

If you want your new terminals to open with a previously generated or specified color palette, add these templates to your ~/.config/hellwal/templates/ folder:

• variables.sh
• terminal.sh

Run hellwal with an image or theme to generate the output scripts from the templates.

Then in .bashrc, add following lines:

source ~/.cache/hellwal/variables.sh
sh ~/.cache/hellwal/terminal.sh

Alternatively if you use fish:

• variablesfish.fish
• terminal.sh

Then add this to your fish config:

source ~/.cache/hellwal/variablesfish.fish
sh ~/.cache/hellwal/terminal.sh

Showcase

Special thanks:

• dylanaraps - for pywal and other amazing stuff he created.