chroma.ts

TypeScript rewrite of chroma-js. Includes:

• Proper ES module support.
• Included typings generated from the source.
• A number of bugfixes.
• No more NaN values.
• Exceptions on invalid inputs.
• Better inline documentation.
• Smaller (11.26 KB gzipped).

Installation

npm install --save chroma.ts

Usage

// in TypeScript / using ES modules
import * as chroma from 'chroma.ts'

// commonjs
const chroma = require('chroma.ts')

chroma.css('powderblue') // create a color
    .darker(2) // transform it
    .gl() // output it

Alternatively, you can include the UMD bundle in a script tag and use the chroma global.

API

.color(red255: number, green255: number, blue255: number, alpha1: number = 1): Color _src

example chroma.color(99, 99, 44, 0.7)

.color(x: Chromable, format?: ColorFormat): Color _src

example chroma.color('mediumorchid') // a css string
example chroma.color([56, 203, 30]) // a RGB triple
example chroma.color(0x4b0082) // a hex num
example chroma.color([30, 0.8, 0.3], 'hsl') // explicit format

.color(colorname: typeof [object Object], format?: undefined | "name"): Color _src

This overload allows VS Code to suggest color names when you type color('.

.color(channel0: number, channel1: number, channel2: number, format: ColorFormat): Color _src

example chroma.color(30, 0.8, 0.3, 'hsl')

.color(channel0: number, channel1: number, channel2: number, channel3: number, format: ColorFormat): Color _src

example chroma.color(0.3, 0.8, 0.3, 1, 'gl')

type Chromable = number | string | Color | number[]

A Chromable is any value which can be converted to a color. For ease of use, most functions accept these instead of only Color values.

interface Color

color.mix(col2: Chromable, f: number, m: InterpolationMode = "rgb"): Color _src

@see [[mix]]

color.rgb(doRound: boolean = true, clamp_: boolean = true): RGB _src

color.rgba(doRound: boolean = true, clamp_: boolean = true): RGBA _src

color.hex(mode: "rgb" | "rgba" | "argb" = "rgb"): string _src

Return a hex-string representation of this color.

@see #num for a hex-number representation.

example chroma.color('yellow').alpha(0.7).hex() "#ffff00"
example chroma.color('yellow').alpha(0.7).hex('rgba') "#ffff00b3"
example chroma.color('yellow').alpha(0.7).hex('argb') "#b3ffff00"

color.hsl(): HSL _src

Returns the [HSL] representation of this color. hue will always be in [0;360). Values are never NaN.

example chroma.color('purple').hsl() [300, 1, ~0.25]

color.hsv(): HSV _src

Returns the [HSL] representation of this color. hue will always be in [0;360). Values are never NaN.

example chroma.color('purple').hsv() [300, 1, ~0.5]

color.hcg(): HCG _src

Returns the [HSL] representation of this color. hue will always be in [0;360). Values are never NaN.

example chroma.color('purple').hcg() [300, ~0.5, 0]

color.css(mode: "rgb" | "hsl" = "rgb"): string _src

Returns a CSS rgb(...) or hsl(...) string representation that can be used as CSS-color definition. The alpha value is not output if it 1.

example chroma.color('teal').css() "rgb(0,128,128)"
example chroma.color('teal').alpha(0.5).css() "rgba(0,128,128,0.5)"
example chroma.color('teal').css('hsl') "hsl(180,100%,25.1%)"

color.name(closest: true): string _src

color.name(closest: false | true = false): string | undefined _src

Get the name of a color. By default, this method will try to match the color exactly (comparing rounded RGB values). Pass true to return the name of the color which is closest to this in CIELAB color space. CIELAB is used as it is perceptually uniform.

example chroma.color('#ff0000').name() "red"
example chroma.color('#ff0001').name()
example chroma.color('#ff0001').name(true) "red"

color.cmyk(): CMYK _src

Get the CMYK representation of this color.

example chroma.color('red').cmyk() [0, 1, 1, 0]

color.gl(): GL _src

Returns the [GL] representation of this color.

example chroma.color('33cc00').gl() [0.2, 0.8, 0, 1]

color.luminance(): number _src

Get luminance of the color. This is equal to the Y channel of the XYZ color space.

example chroma.color('black').luminance() 0
example chroma.color('white').luminance() ~1
example chroma.color('red').luminance() ~0.21

@see https://en.wikipedia.org/wiki/Relative\_luminance

color.luminance(lum1: number): this _src

Return a new [Color] with lum1 by linearly interpolating this with white (when increasing the luminance) or black (otherwise) in the [XYZ] color space.

@see https://en.wikipedia.org/wiki/Relative\_luminance

example // Approximately doubling the luminance of red
example chroma.color('red').luminance(0.4) // "Vivid Tangerine"

color.temperature(): number _src

Get color temperature of this color in Kelvin. This only makes sense for colors close to those output by kelvin

example [c = chroma.color('#ff3300'), c.temperature()] [, 943]
example [c = chroma.color('#ffe3cd'), c.temperature()] [, 4998]
example [c = chroma.color('#b3ccff'), c.temperature()] [, 15169]

color.set(modeAndChannel: string, value: number | ((channel: number) => number)): Color _src

Returns a new [Color] with a channel changed.

example chroma.color('skyblue').set('hsl.h', 0) // change hue to 0 deg (=red)
example chroma.color('hotpink').set('lch.c', 30) // set chromaticity to 30
example chroma.color('orangered').set('lab.l', x => x / 2) // half Lab lightness
example chroma.color('darkseagreen').set('lch.c', x => x * 2) // double Lch saturation

color.clipped(): boolean _src

Returns whether this color is outside the RGB color cube and will be clipped/clamped when calling .rgb()

example [c = chroma.lch( 20, 40, 50), c.clipped()] [, true]
example [c = chroma.lch( 40, 40, 50), c.clipped()] [, false]
example [c = chroma.lch( 60, 40, 50), c.clipped()] [, false]
example [c = chroma.lch( 80, 40, 50), c.clipped()] [, true]
example [c = chroma.lch(100, 40, 50), c.clipped()] [, true]

color.textColor(): Color _src

Returns black or white, whichever has the highest contrast to this. In the readme you should see the result of this.

example chroma.color('red')
example chroma.color('yellow')

color.alpha(): number _src

Get alpha value of color.

example chroma.rgb(0, 0, 255, 0.5).alpha() 0.5

color.alpha(alpha1: number): Color _src

Return new [Color] with given alpha value.

example chroma.color('green').alpha(0.3)
example chroma.color('green').alpha(0.3).hex('rgba') "#0080004d"

color.darker(amount: number = 1): Color _src

color.brighter(amount: number = 1): Color _src

example chroma.color('hotpink')
example chroma.color('hotpink').brighter()
example chroma.color('hotpink').brighter(2)
example chroma.color('hotpink').brighter(3)

color.saturate(amount: number = 1): Color _src

Returns a new [Color] with increased saturation.

example chroma.color('slategray')
example chroma.color('slategray').saturate()
example chroma.color('slategray').saturate(2)
example chroma.color('slategray').saturate(3)

color.desaturate(amount: number = 1): Color _src

Equivalent to saturate(-amount).

@see #saturate

color.premultiplied(): Color _src

color.hsi(): HSI _src

Returns the [HSI] representation of this color. hue will always be in [0; 360). Values are never NaN.

example chroma.color('purple').hsi() [300, 1, ~0.33]

color.lab(): RGB _src

Returns the [LAB] representation of this color.

example chroma.color('purple').lab() [~29.78, ~58.93, ~-36.49]

color.num(mode: "rgb" | "rgba" | "argb" = "rgb"): number _src

Return a hex-num of this color.

@see #num for a hex-number representation.

example chroma.color('yellow').alpha(0.7).hex() "#ffff00"
example chroma.color('yellow').alpha(0.7).hex('rgba') "#ffff00b3"
example chroma.color('yellow').alpha(0.7).hex('argb') "#b3ffff00"

color.lch(): LCH _src

Returns the [LCH] representation of this color. hue will always be in [0; 360). Values are never NaN.

example chroma.color('purple').lch() [~29.78, ~69.31, ~328.23]

color.xyz(): XYZ _src

Returns the [XYZ] representation of this color. hue will always be in [0; 360). Values are never NaN.

example chroma.color('purple').xyz() [~0.13, ~0.06, ~0.21]

color.equals(color: Color): boolean _src

Whether this Color is identical (strict equality of r, g, b, a) to color.

color.hashCode(): number _src

color.toSource(): string _src

example chroma.color('red').toSource() "chroma.rgb(255, 0, 0)"
example chroma.rgb(-2, 100.02, 200, 0.5).toSource() "chroma.rgb(-2, 100.02, 200, 0.5)"

color.toString(): string _src

color.kelvin(): number _src

namespace black

example chroma.black

namespace white

example chroma.black

.cubehelix(start: number = 300, rotations: number = -1.5, hue: number | [number, number] = 1, gamma: number = 1, lightness: number | [number, number] = [0, 1]): CubeHelix _src

Return a new [[CubeHelix]].

example chroma.cubehelix() // use the default helix
example chroma.cubehelix().start(200).rotations(-0.5).gamma(0.8).lightness([0.3, 0.8])

interface CubeHelix

Dave Green's cubehelix color scheme!

A CubeHelix is a function defined on [0, 1] which returns colors.

cubehelix(f: number): Color _src

Dave Green's cubehelix color scheme!

A CubeHelix is a function defined on [0, 1] which returns colors.

cubehelix.start(): number _src

cubehelix.start(s: number): this _src

cubehelix.rotations(): number _src

cubehelix.rotations(r: number): this _src

cubehelix.gamma(): number _src

cubehelix.gamma(g: number): this _src

cubehelix.hue(): [number, number] _src

cubehelix.hue(h: number | [number, number]): this _src

cubehelix.lightness(): [number, number] _src

cubehelix.lightness(h: number | [number, number]): this _src

cubehelix.scale(): Scale _src

Convert to a [[Scale]].

example chroma.cubehelix().scale().correctLightness().domain(2, 22)

cubehelix.at(fract: number): Color _src

.random(randomSource: random = Math.random): Color _src

Create a new random [Color] from a random point in the RGB color space.

.mix(col1: Chromable, col2: Chromable, f: number = 0.5, m: InterpolationMode = "rgb"): Color _src

Mixes two colors. The mix ratio is a value between 0 and 1. The color mixing produces different results based the color space used for interpolation.

example chroma.mix('red', 'blue')
example chroma.mix('red', 'blue', 0.25)
example chroma.mix('red', 'blue', 0.75)
example chroma.mix('red', 'blue', 0.5, 'rgb')
example chroma.mix('red', 'blue', 0.5, 'hsl')
example chroma.mix('red', 'blue', 0.5, 'lab')
example chroma.mix('red', 'blue', 0.5, 'lch')
example chroma.mix('red', 'blue', 0.5, 'lrgb')

.css(cssString: string): Color _src

Parse a CSS color. See MDN for all the possible variants.

example chroma.css('hsl(2rad 90% 50% / 0.9)')
example chroma.css('laserlemon')

.cmyk(cmyk: CMYK): Color _src

example chroma.cmyk(0.2, 0.8, 0, 0)
example chroma.color(0.2, 0.8, 0, 0, 'cmyk')

.cmyk(cyan1: number, magenta1: number, yellow1: number, key1: number): Color _src

.gl(gl: RGBA | RGB): Color _src

example chroma.gl(1, 1, 0, 1)

.gl(red1: number, green1: number, blue1: number, alpha1: number): Color _src

example chroma.gl([1, 0, 1, 0.5])

.hcg(hcg: HCG): Color _src

.hcg(h: number, c: number, g: number, alpha1: number = 1): Color _src

.lch(lch: LCH): Color _src

.lch(h: number, c: number, l: number, alpha1: number = 1): Color _src

.hsi(hsi: HSI): Color _src

.hsi(h: number, s: number, i: number, alpha1: number = 1): Color _src

.hsl(hsl: HSL): Color _src

.hsl(hueDegrees: number, saturation1: number, lightness1: number, alpha1: number = 1): Color _src

example chroma.hsl(30, 1, 0.5)
example chroma.hsl(30, 0.6, 0.5)

.hsv(hsv: LAB): Color _src

.hsv(h: number, s: number, v: number): Color _src

.kelvin(temperature: number): Color _src

example chroma.kelvin(2000) // candle light
example chroma.kelvin(3500) // sunset
example chroma.kelvin(6500) // daylight
example x0_1 => chroma.kelvin(x0_1 * 30000) // effective range: [0; 30000]

.lab(lab: LAB): Color _src

.lab(lightness1: number, a1: number, b: number, alpha1: number = 1): Color _src

.num(num: number): Color _src

example chroma.num(0x663399) // rebeccapurple

.rgb(rgb: RGBA | RGB): Color _src

.rgb(red255: number, green255: number, blue255: number, alpha1: number = 1): Color _src

example chroma.rgb(0, 100, 200)

.xyz(xyz: XYZ): Color _src

.xyz(x1: number, y1: number, z1: number, alpha1: number = 1): Color _src

.average(chromables: Chromable[], mode: InterpolationMode = "rgb"): Color _src

Similar to mix, but accepts more than two colors.

example colors = ['#ddd', 'yellow', 'red', 'teal'] [, , , ]
example chroma.average(colors) // default = 'rgb'
example chroma.average(colors, 'lab')
example chroma.average(colors, 'lch')
example chroma.average(colors, 'lrgb')
example chroma.average(['red', 'rgba(0,0,0,0.5)']).css() "rgba(128,0,0,0.75)"

.bezier(chromables: Chromable[]): (t: number) => Color _src

example chroma.scale('black', 'red', 'gold') // linear interpolation
example chroma.bezier('black', 'red', 'gold') // bezier interpolation

.bezier(...chromables: Chromable[]): (t: number) => Color _src

.blend(bottom: Chromable, top: Chromable, mode: BlendMode): Color _src

Blends two colors using RGB channel-wise blend functions.

example chroma.blend('4CBBFC', 'EEEE22', 'multiply')
example chroma.blend('4CBBFC', 'EEEE22', 'darken')
example chroma.blend('4CBBFC', 'EEEE22', 'lighten')

type BlendMode = typeof [object Object]

.scale(colors: Chromable[] | typeof [object Object] | ((f: number) => Color)): Scale _src

example scale = chroma.scale(['yellow', '008ae5'])
example scale(0.25)
example scale(0.5)
example scale(0.75)
example chroma.scale('Viridis')

.scale(...colors: Chromable[]): Scale _src

interface Scale<T>

A color scale, created with scale, is a function that maps numeric values to a color palette.

The type parameter describes the output type and can be changed with out(). Defaults to Color objects.

example chroma.scale('Purples')
example chroma.scale('Purples')(0.4)

scale(val: number): T _src

A color scale, created with scale, is a function that maps numeric values to a color palette.

The type parameter describes the output type and can be changed with out(). Defaults to Color objects.

example chroma.scale('Purples')
example chroma.scale('Purples')(0.4)

scale.classes(): number[] _src

Get the current scale classes.

scale.classes(classes: number | number[]): this _src

Make the scale return a number of distint color instead of a continuous gradient. If you pass a number the scale will broken into equi-distant classes:

example chroma.scale('OrRd') // continous
example chroma.scale('OrRd').classes(5) // equidistant classes
example chroma.scale('OrRd').classes(8)
example chroma.scale('OrRd').classes([0, 6, 11, 17, 20]) // also sets domain

scale.domain(): number[] _src

Get the domain.

example chroma.scale("red", "white", "blue").domain(0, 20).domain() [0, 10, 20]

scale.domain(start: number, end: number): this _src

Set the domain interval on which the scale is defined. Colors are distributed equidistantly along the interval.

example chroma.scale("red", "white", "blue").domain(0, 100)(50)
example chroma.scale("red", "white", "blue").domain(0, 0.25, 1).domain(0, 100).domain() [0, 50, 100]

scale.domain(...domain: number[]): this _src

Set the domain interval and the individual positions of the colors. The number of passed values must match the number of colors which define the scale. Not valid if the scale is defined by a function.

example scale = chroma.scale("red", "white", "blue").domain(0, 25, 100)
example scale(25)
example scale(100)
example scale(50)

scale.mode(): InterpolationMode _src

Get the interpolation mode used when calculating colors.

scale.mode(mode: InterpolationMode): this _src

Set the interpolation mode used when calculating colors. The defaut mode is "rgb". See also {@link chroma#mix}

example chroma.scale("red", "green").mode("lab")
example chroma.scale("red", "green").mode("lrgb")

scale.out<M>(outputFormat: M): Scale _src

Set the output format return by this(x) and this.colors(n).

example chroma.scale("red", "white").out("hex")(0) "#ff0000"
example chroma.scale("red", "white").out("num").colors(2) [, ]

scale.correctLightness(enableCorrectLightness: boolean = true): this _src

This makes sure the lightness range is spread evenly across a color scale. Especially useful when working with multi-hue color scales, where simple gamma correction can't help you very much.

example chroma.scale('black','red','yellow','white')
example chroma.scale('black','red','yellow','white').correctLightness()

scale.padding(): [number, number] _src

Get the padding.

scale.padding(paddingLeft: number, paddingRight: number = paddingLeft): this _src

Set the padding. Positive values will "cut off" the ends of gradient, while negative values will add a section of constant color at the ends.

example chroma.scale("red", "white").padding(0.2)
example chroma.scale("red", "white").padding(0.1)(0)
example chroma.scale("red", "white").padding(-0.1)(0)

scale.colors<M>(numColors?: undefined | number, format: M = "hex" as any): Array _src

Get a number of equidistant colors.

example chroma.scale('OrRd').colors(5) [, , , , ]
example chroma.scale(['white', 'black']).colors(12) [, , , , , , , , , , , ]

scale.cache(): boolean _src

Get whether the cache is enabled. Defaults to true.

scale.cache(enableCache: boolean): this _src

Enable or disable the cache.

scale.gamma(): number _src

Get the current gamma value. Defaults to 1.

scale.gamma(gamma: number): this _src

Set the gamma value. Gamma-correction can be used to "shift" a scale's center more the the beginning (gamma <

1. or end (gamma > 1), typically used to "even" the lightness gradient. Default is 1.

example chroma.scale('YlGn').gamma(0.5)
example chroma.scale('YlGn').gamma(1)
example chroma.scale('YlGn').gamma(2)

namespace scales

scales.cool(): Scale _src

example chroma.scales.cool()

scales.hot(): Scale _src

example chroma.scales.hot()

.contrast(a: Chromable, b: Chromable): number _src

Computes the WCAG contrast ratio between two colors. A minimum contrast of 4.5:1 is recommended to ensure that text is still readable against a background color.

.distance(a: Chromable, b: Chromable, mode: ColorMode = "lab"): number _src

Compute the euclidean distance between two colors in a given color space.

example chroma.distance('#fff', '#ff0', 'rgb') 255
example chroma.distance('#fff', '#f0f', 'rgb') 255
example chroma.distance('#fff', '#ff0') ~96.95
example chroma.distance('#fff', '#f0f') ~122.16

.deltaE(reference: Chromable, sample: Chromable, L: number = 1, C: number = 1): number _src

Computes color difference as developed by the Colour Measurement Committee of the Society of Dyers and Colourists (CMC) in 1984. The implementation is adapted from Bruce Lindbloom. The parameters L and C are weighting factors for lightness and chromaticity.

example [r = '#ededee', s = '#edeeed', chroma.deltaE(r, s)] [, , ~1.64]
example [r = '#ececee', s = '#eceeec', chroma.deltaE(r, s)] [, , ~3.16]
example [r = '#e9e9ee', s = '#e9eee9', chroma.deltaE(r, s)] [, , ~7.36]
example [r = '#e4e4ee', s = '#e4eee4', chroma.deltaE(r, s)] [, , ~14.84]
example [r = '#e0e0ee', s = '#e0eee0', chroma.deltaE(r, s)] [, , ~21.32]

.analyze(data: number[]): DataInfo _src

.limits(data: number[] | DataInfo, mode: LimitsMode = "e", num: number = 7): number[] _src

type ColorMode = "rgb" | "cmyk" | "lab" | "hsv" | "hsi" | "hcg" | "hsl" | "gl" | "lch" | "xyz"

type InterpolationMode = "rgb" | "lab" | "hsv" | "hsi" | "hcg" | "hsl" | "lch" | "xyz" | "lrgb" | "num"

type ColorFormat = ColorMode | "hex" | "num" | "name" | "kelvin" | "css"

License

The original chroma-js library is released under the BSD license.

The included brewer colors are released under the Apache 2.0 license.

chroma.ts modifications are also released under the BSD license.