spectrum

https://github.com/twoism-dev/sinatra-tinycache

Color is a Ruby library to provide basic RGB, CMYK, HSL, and other colourspace manipulation support to applications that require it. It also provides 152 named RGB colours (184 with spelling variations) that are commonly supported in HTML, SVG, and X11 applications. A technique for generating monochromatic contrasting palettes is also included.