ColorHash

Generate a color based on a given String, by calculating a color value from the String's hash. The result is deterministic: the same value will always result in the same color (so long as the hash function remains deterministic).

Generated colours can be useful to dynamically generate tags like these:

Installation

Install the gem and add to the application's Gemfile by executing:

$ bundle add color_hash

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install color_hash

Usage

By default, ColorHash will generate color values in the Hue range between [0..360], and with a lightness and saturation value of one of [0.35, 0.5, 0.65].

color_hash = ColorHash.new()

hex = color_hash.hex("Hello World!")
hsl = color_hash.hsl("Hello World!")
rgb = color_hash.rgb("Hello World!")

The resulting values are going to be:

hex = "#d2797c"
hsl = [358, 0.5, 0.65]
rgb = [210, 121, 124]

You can customize the desired hue range(s), saturation and lightness values by passing the corresponding arguments to the constructor. For example, to generate colors in the blue spectrum:

color_hash = ColorHash.new(hue: [{min: 180, max: 240}])
color = color_hash.hex("Hello World!")

will result in a color value of:

color = "#79acd2"

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/kuyio/color_hash.

Attribution

See https://github.com/zenozeng/color-hash for the original implementation in JavaScript.