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.