Ruby Chromatic

A Ruby gem for generating harmonious color palettes from a single base color using color theory algorithms. Works as both a CLI tool and a Ruby library.

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Features

• Generate palettes using 5 color theory modes: complementary, analogous, triadic, tetradic, and shades
• Output in 3 formats: plain text, CSS custom properties, and JSON
• Full HEX, RGB, and HSL color conversion
• Usable as a CLI tool or embedded as a Ruby library

Installation

Add to your Gemfile:

gem 'ruby-chromatic'

Then run:

bundle install

Or install directly:

gem install ruby-chromatic

Usage

CLI

# Generate a complementary palette (default)
chromatic generate "#3498db"

# Specify a mode
chromatic generate "#3498db" triadic

# Output as CSS custom properties
chromatic generate "#3498db" triadic --format css

# Output as JSON with 7 shades
chromatic generate "#e74c3c" shades --format json --steps 7

# Show version
chromatic version

Available modes:

Mode	Description
complementary	2 colors opposite on the color wheel
analogous	3 colors adjacent on the color wheel
triadic	3 colors evenly spaced at 120 degrees
tetradic	4 colors evenly spaced at 90 degrees
shades	Lightness gradient from dark to light

Available formats: text (default), css, json

Ruby Library

require 'chromatic'

# Create a color
color = Chromatic::Color.from_hex('#3498db')

# Convert between formats
color.to_hex   # => "#3498db"
color.to_rgb   # => "rgb(52, 152, 219)"
color.to_hsl   # => { h: 204.1, s: 69.9, l: 53.1 }

# Generate palettes
palette = Chromatic::Generator.complementary(color)
palette = Chromatic::Generator.triadic(color)
palette = Chromatic::Generator.shades(color, steps: 7)

# Format output
puts Chromatic::Formatter.css(palette)
puts Chromatic::Formatter.json(palette)
puts Chromatic::Formatter.text(palette)

Example CSS output:

:root {
  --triadic-1: #3498db;
  --triadic-2: #db3498;
  --triadic-3: #98db34;
}

Development

git clone https://github.com/sha-wrks/Ruby-Chromatic.git
cd Ruby-Chromatic
bundle install
bundle exec rspec

Contributing

Contributions are welcome. Please read CONTRIBUTING.md before submitting a pull request.

Security

To report a vulnerability, see SECURITY.md.

License

Released under the MIT License. Copyright (c) 2026 Yansha.