gamut

Go package to generate and manage color palettes & schemes

import "github.com/muesli/gamut"
import "github.com/muesli/gamut/palette"
import "github.com/muesli/gamut/theme"

Colors

gamut operates on various color spaces internally, but all color values you pass in as parameters and all return values will match Go’s color.Color interface.

Let’s start with the basics. Just for convenience there’s a hex-value parser:

color = gamut.Hex("#333")
color = gamut.Hex("#ABCDEF")

Both the short and standard formats are supported.

Around the Color Wheel

The Darker and Lighter functions darken and lighten respectively a given color value by a specified percentage, without changing the color's hue:

// returns a 10% darker version of color
color = gamut.Darker(color, 0.1)
// returns a 30% lighter version of color
color = gamut.Lighter(color, 0.3)

Complementary returns the complementary color for a given color:

color = gamut.Complementary(color)

Contrast returns the color with the highest contrast to a given color, either black or white:

color = gamut.Contrast(color)

To retrieve a color with the same lightness and saturation, but a different angle on the color wheel, you can use the HueOffset function:

color = gamut.HueOffset(color, 90)

You can also go in the opposite direction by using negative values.

Schemes

All the following functions return colors of a different hue, but with the same lightness and saturation as the given colors:

Triadic schemes are made up of three hues equally spaced around the color wheel:

colors = gamut.Triadic(color)

Quadratic schemes are made up of four hues equally spaced around the color wheel:

colors = gamut.Quadratic(color)

Tetradic schemes are made up by two colors and their complementary values:

colors = gamut.Tetradic(color1, color2)

Analogous schemes are created by using colors that are next to each other on the color wheel:

colors = gamut.Analogous(color)

SplitComplementary schemes are created by using colors next to the complementary value of a given color:

colors = gamut.SplitComplementary(color)

Warm/Cool Colors

ok = gamut.Warm(color)
ok = gamut.Cool(color)

Shades, Tints & Tones

Monochromatic returns colors of the same hue, but with a different saturation/lightness:

colors = gamut.Monochromatic(color, 8)

Shades returns colors blended from the given color to black:

colors = gamut.Shades(color, 8)

Tints returns colors blended from the given color to white:

colors = gamut.Tints(color, 8)

Tones returns colors blended from the given color to gray:

colors = gamut.Tones(color, 8)

Blending Colors

Blends returns interpolated colors by blending two colors:

colors = gamut.Blends(color1, color2, 8)

Palettes

Gamut comes with six curated color palettes: Wikipedia, Crayola, CSS, RAL, Resene, and Monokai. The Wikipedia palette is an import of common colors from Wikipedia’s List of Colors. New curated palettes and importers are welcome. Send me a pull request!

The function Colors lets you retrieve all colors in a palette:

for _, c := range palette.Wikipedia.Colors() {
    fmt.Println(c.Name, c.Color)
}

This will print out a list of 1609 color names, as defined by Wikipedia.

Creating Your Own Palettes

var p gamut.Palette
p.AddColors(
    gamut.Colors{
        {"Name", gamut.Hex("#123456"), "Reference"},
        ...
    }
)

Name and Reference are optional when creating your own palettes.

Names

Each color in the curated palettes comes with an “official” name. You can filter palettes by colors with specific names. This code snippet will return a list of all “blue” colors in the Wikipedia palette:

colors = palette.Wikipedia.Filter("blue")

You can access a color with a specific name using the Color function:

color, ok = palette.Wikipedia.Color("Pastel blue")

Calling a palette’s Name function with a given color returns the name & distance of the closest (perceptually) matching color in it:

name, distance = palette.Wikipedia.Name(color)
// name = "Baby blue"
// distance between 0.0 and 1.0

Mixing Palettes

You can combine all colors of two palettes by mixing them:

p = palette.Crayola.MixedWith(palette.Monokai)

Perception

Sometimes you got a slice of colors, but you have a limited color palette to work with. The Clamped function returns a slice of the closest perceptually matching colors in a palette, maintaining the same order as the original slice you provided. Finally you can remix your favorite wallpapers in Crayola-style!

colors = palette.Crayola.Clamped(colors)

Generating Color Palettes

Color Generators, like the provided PastelGenerator, WarmGenerator or HappyGenerator can produce random (within the color space constraints of the generator) color palettes:

colors, err = gamut.Generate(8, gamut.PastelGenerator{})

The SimilarHueGenerator produces colors with a hue similar to a given color:

colors, err = gamut.Generate(8, gamut.SimilarHueGenerator{Color: gamut.Hex("#2F1B82")})

Using the ColorGenerator interface, you can also write your own color generators:

type BrightGenerator struct {
	BroadGranularity
}

func (cc BrightGenerator) Valid(col colorful.Color) bool {
	_, _, l := col.Lab()
	return 0.7 <= l && l <= 1.0
}

...
colors, err := gamut.Generate(8, BrightGenerator{})

Only colors with a lightness between 0.7 and 1.0 will be accepted by this generator.

Themes

Roles

color = theme.MonokaiTheme.Role(theme.Foreground)

Available roles are Foreground, Background, Base, AlternateBase, Text, Selection, Highlight.