The corkscrew package for Typst includes a set of functions to generate color scales based on Dave Green’s cubehelix color scheme (arXiv link).

Add corkscrew to your project using the following code:

#import "@preview/corkscrew:0.1.0" as chx

cubehelix()

Given a number (integer or float), returns the color at the corresponding point on the default cubehelix color scale.

Parameters

• value (required, positional): The numeric value (integer or float) to map to a color. Values outside the input domain are clipped.
• domain (optional, named): Change the input domain. Set this to a single number n (integer or float) to get a domain of 0..n. Set this to an array of 2 numbers (n1, n2) to get a domain of n1..n2. Default: (0.0, 1.0)
• type (optional, named): Set this to dictionary to return the raw calculated RGB values as a dictionary with the keys r, g and b. Default: color

Examples

#box(fill: chx.cubehelix(0))
#box(fill: chx.cubehelix(0.25))
#box(fill: chx.cubehelix(0.5))
#box(fill: chx.cubehelix(0.75))
#box(fill: chx.cubehelix(3, domain: (0, 4)))

#{
  let body = lorem(54)
  let length = body.len()
  let i = 0
  for char in body {
    text(fill: chx.cubehelix(i, domain: length), char)
    i += 1
  }
}

new()

Generates a cubehelix color scale and returns a mapping function that maps a numeric value to a color on that scale.

All parameters are optional and named. The function returned by new() with default parameters is equivalent to the cubehelix() function.

Parameters

• start: The hue to start from. A value of 1 starts at red, 2 starts at green, and 3 starts at blue. Values above 3 are converted to the value modulo 3. Default: 0.5
• rotations: How many R→G→B→R… rotations are made from the start to the end of the scale. Negative values rotate in reverse (B→G→R→B…). Default: -1.5
• saturate: Controls how saturated the colors are. A value of 0 produces a totally greyscale palette. Values above 1.0 may produce out-of-gamut values, which will be clipped. Default: 1.0
• gamma: Lightens or darkens the midtones of the scale, to emphasize lower or higher values. Values below 1.0 lighten the midtones of the scale, while values above 1.0 darken the midtones. Default: 1.0
• reverse: Setting this to true reverses the lightness of the scale, so it starts at 100% lightness and ends at 0%. Default: false
• The domain and type parameters may also be set here. They behave identically to their corresponding parameters in the mapping function.

Mapping function

Given a number (integer or float), returns the color at the corresponding point on the color scale generated with new().

Parameters

• value (required, positional): The numeric value (integer or float) to map to a color. Values outside the domain are clipped to the domain.
• domain (optional, named): Change the input domain. Set this to a single number n (integer or float) to get a domain of 0..n. Set this to an array of 2 numbers (n1, n2) to get a domain of n1..n2. Default: (0.0, 1.0), unless changed in new()
• type (optional, named): Set this to dictionary to return the raw calculated RGB values as a dictionary with the keys r, g and b. Default: color, unless changed in new()

Examples

#let cool-scale = chx.new(
  rotations: -0.5,
  saturate: 1.5,
  gamma: 0.9,
)

#box(fill: cool-scale(0))
#box(fill: cool-scale(0.25))
#box(fill: cool-scale(0.5))
#box(fill: cool-scale(0.75))
#box(fill: cool-scale(3, domain: (0, 4)))

#{
  let body = lorem(54)
  let length = body.len()
  let i = 0
  for char in body {
    text(fill: cool-scale(i, domain: length), char)
    i += 1
  }
}

#let wild-scale = chx.new(
  start: 2,
  rotations: 13,
  saturate: 4,
  gamma: 1.1,
  reverse: true,
)

#box(fill: wild-scale(0))
#box(fill: wild-scale(0.25))
#box(fill: wild-scale(0.5))
#box(fill: wild-scale(0.75))
#box(fill: wild-scale(3, domain: (0, 4)))

#{
  let body = lorem(54)
  let length = body.len()
  let i = 0
  for char in body {
    text(fill: wild-scale(i, domain: length), char)
    i += 1
  }
}

colors()

Returns an array of colors taken from evenly-spaced points on the color scale.

Parameters

• num (required, positional): the number of colors to generate. Must be a positive integer.
• func (optional, named): the mapping function used to generate the color scale. Default: cubehelix

Examples

#grid(
  columns: 12 * (2em,),
  ..chx.colors(12).map(it => block(fill: it))
)
#grid(
  columns: 12 * (2em,),
  ..chx.colors(12, func: cool-scale).map(it => block(fill: it))
)
#grid(
  columns: 12 * (2em,),
  ..chx.colors(12, func: wild-scale).map(it => block(fill: it))
)

gradient-map()

A helper function that, given a mapping function, returns an array of colors suitable for use in gradients.

The function gradient-map(func) is equivalent to colors(256, func: func).

Use this in gradients by destructuring the returned array, i.e. gradient.linear(..chx.gradient-map(func)).

#set block(width: 100%, height: 4em)
#block(fill: gradient.linear(..chx.gradient-map(chx.cubehelix)))
#block(fill: gradient.linear(..chx.gradient-map(cool-scale)))
#block(fill: gradient.linear(..chx.gradient-map(wild-scale)))

gradient array

The default color palette as an array of colors suitable for use in gradients. Equivalent to gradient-map(cubehelix).

Use this in gradients by destructuring the array, i.e. gradient.linear(..chx.gradient).

#set block(width: 100%, height: 4em)
#block(fill: gradient.linear(..chx.gradient))