Color Tools

Performance optimized useful tools for working with colors. This package is a module of the nextcss project. It provides a comprehensive set of color conversion and manipulation utilities for both browser and Node.js environments with full TypeScript support.

Table of Contents

General

Installation ▪ Quick Start ▪ Compatibility ▪ Benchmarks

Conversion Functions

HEX ▪ RGB ▪ HSL ▪ HWB ▪ OKLAB ▪ CMYK

Additional Functions

Color Shift ▪ Tone Map ▪ Brightness ▪ Colorify ▪ Random Colors

Other

Guidelines ▪ License

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Installation

yarn add -D @nextcss/color-tools

npm i -D @nextcss/color-tools

Quick Start

import { hsl2hex, hslColorShift, toneMap, brightness } from '@nextcss/color-tools';

// Convert HSL to HEX
const hex = hsl2hex([207, 90, 54]);

// Lighten a color by 20%
const lightened = hslColorShift(hex, 20);

// Generate a full tone scale from the lightened color
const scale = toneMap(lightened);

// Check perceived brightness for contrast decisions
const brightnessValue = brightness(lightened);

Compatibility

This package works in both browser and Node.js environments. It includes ESM and CommonJS builds, so both import and require statements work everywhere. Full TypeScript support is included.

Benchmarks

Environment: Benchmarks were run on an Intel Core i5-12600K, Node.js v22.16.0, using Benny in a single-threaded environment. Results are measured in operations per second (ops/s) - higher is better.

Baseline: nextcss vs. colord (ops/s)

Operation	colord	nextcss	Δ
HEX → RGB	5,899,814	16,842,215	+185%
HEX → HSL	5,819,305	13,408,262	+130%
RGB → HEX	2,938,363	62,153,898	+2016%
RGB → HSL	3,489,380	57,524,837	+1549%

Note: colord is used as a baseline reference only — it uses a chainable wrapper architecture with additional overhead, so numbers are not a direct apples-to-apples comparison, but give a familiar point of reference.

Internal conversion throughput (ops/s)

From \ To	HEX	RGB	HSL	HWB	OKLAB	CMYK
HEX	—	17.1M	13.5M	13.8M	4.8M	13.4M
RGB	61.3M	—	57.0M	54.7M	5.1M	49.6M
HSL	11.0M	16.2M	—	13.5M	3.9M	12.4M
HWB	32.1M	69.5M	32.7M	—	4.9M	29.9M
OKLAB	5.8M	7.7M	6.2M	6.1M	—	6.1M
CMYK	15.5M	77.7M	37.3M	39.9M	5.0M	—

Note: OKLAB conversions are intentionally slower — they involve perceptually uniform color math with significantly more CPU-intensive calculations (non-linear gamma expansion, matrix transforms) compared to geometric color space conversions like HSL or HWB.

Other operations

Operation	Fastest	ops/s	Slowest	ops/s
Random color generation	HSL	94,094,590	OKLAB	3,559,931
Color shifting	RGB	7,915,344	OKLAB	2,209,869
Tone mapping	RGB	200,815	OKLAB	93,504

Note: Tone mapping operates on a fundamentally different scale — it internally uses color shifting, adding cumulative overhead per step — sub-200K ops/s reflects this layered computation rather than a single conversion.

Conversion Functions

The library provides comprehensive conversion functions between HEX, RGB, HSL, HWB, OKLab, and CMYK color spaces.

HEX Conversions

Convert from HEX to other color spaces.

Syntax

hex2rgb(hex: string): [red, green, blue, alpha?] | undefined
hex2hsl(hex: string): [hue, saturation, lightness, alpha?] | undefined
hex2hwb(hex: string): [hue, whiteness, blackness, alpha?] | undefined
hex2oklab(hex: string): [lightness, a, b, alpha?] | undefined
hex2cmyk(hex: string): [cyan, magenta, yellow, black, alpha?] | undefined

Return values:

• hex2rgb: [red (0-255), green (0-255), blue (0-255)] or with alpha (0-100)
• hex2hsl: [hue (0-360), saturation (0-100), lightness (0-100)] or with alpha (0-100)
• hex2hwb: [hue (0-360), whiteness (0-100), blackness (0-100)] or with alpha (0-100)
• hex2oklab: [lightness (0-1), a (-0.4 to 0.4), b (-0.4 to 0.4)] or with alpha (0-100)
• hex2cmyk: [cyan (0-100), magenta (0-100), yellow (0-100), black (0-100)] or with alpha (0-100)

Example

import { hex2rgb, hex2hsl, hex2hwb, hex2oklab, hex2cmyk } from '@nextcss/color-tools';

hex2rgb('#eee'); // [238, 238, 238]
hex2rgb('#2196f3bf'); // [33, 150, 243, 75]

hex2hsl('#2196f3'); // [207, 90, 54]
hex2hsl('#2196f3bf'); // [207, 90, 54, 75]

hex2hwb('#ff0000'); // [0, 0, 0]
hex2oklab('#269dd9'); // [0.627, 0.224, 0.125]
hex2cmyk('#ff0000'); // [0, 100, 100, 0]

RGB Conversions

Convert from RGB array to other formats.

Array format: [red, green, blue, alpha?]

• red, green, blue: 0–255
• alpha (optional): 0–100

Syntax

rgb2hex(rgb: [red, green, blue, alpha?]): string | undefined
rgb2hsl(rgb: [red, green, blue, alpha?]): [hue, saturation, lightness, alpha?] | undefined
rgb2hwb(rgb: [red, green, blue, alpha?]): [hue, whiteness, blackness, alpha?] | undefined
rgb2oklab(rgb: [red, green, blue, alpha?]): [lightness, a, b, alpha?] | undefined
rgb2cmyk(rgb: [red, green, blue, alpha?]): [cyan, magenta, yellow, black, alpha?] | undefined

Return values:

• rgb2hex: HEX color string (e.g. '#ff0000')
• rgb2hsl: [hue (0-360), saturation (0-100), lightness (0-100)] or with alpha (0-100)
• rgb2hwb: [hue (0-360), whiteness (0-100), blackness (0-100)] or with alpha (0-100)
• rgb2oklab: [lightness (0-1), a (-0.4 to 0.4), b (-0.4 to 0.4)] or with alpha (0-100)
• rgb2cmyk: [cyan (0-100), magenta (0-100), yellow (0-100), black (0-100)] or with alpha (0-100)

Example

import { rgb2hex, rgb2hsl, rgb2hwb, rgb2oklab, rgb2cmyk } from '@nextcss/color-tools';

rgb2hex([238, 238, 238]); // '#eeeeee'
rgb2hex([33, 150, 243, 75]); // '#2196f3bf'

rgb2hsl([255, 0, 0]); // [0, 100, 50]
rgb2hsl([255, 0, 0, 50]); // [0, 100, 50, 50]

rgb2hwb([255, 0, 0]); // [0, 0, 0]
rgb2oklab([255, 0, 0]); // [0.627, 0.224, 0.125]
rgb2cmyk([255, 0, 0]); // [0, 100, 100, 0]

HSL Conversions

Convert from HSL array to other formats.

Array format: [hue, saturation, lightness, alpha?]

• hue: 0–360 (degrees)
• saturation: 0–100 (%)
• lightness: 0–100 (%)
• alpha (optional): 0–100

Syntax

hsl2hex(hsl: [hue, saturation, lightness, alpha?]): string | undefined
hsl2rgb(hsl: [hue, saturation, lightness, alpha?]): [red, green, blue, alpha?] | undefined
hsl2hwb(hsl: [hue, saturation, lightness, alpha?]): [hue, whiteness, blackness, alpha?] | undefined
hsl2oklab(hsl: [hue, saturation, lightness, alpha?]): [lightness, a, b, alpha?] | undefined
hsl2cmyk(hsl: [hue, saturation, lightness, alpha?]): [cyan, magenta, yellow, black, alpha?] | undefined

Return values:

• hsl2hex: HEX color string (e.g. '#ff0000')
• hsl2rgb: [red (0-255), green (0-255), blue (0-255)] or with alpha (0-100)
• hsl2hwb: [hue (0-360), whiteness (0-100), blackness (0-100)] or with alpha (0-100)
• hsl2oklab: [lightness (0-1), a (-0.4 to 0.4), b (-0.4 to 0.4)] or with alpha (0-100)
• hsl2cmyk: [cyan (0-100), magenta (0-100), yellow (0-100), black (0-100)] or with alpha (0-100)

Example

import { hsl2hex, hsl2rgb, hsl2hwb, hsl2oklab, hsl2cmyk } from '@nextcss/color-tools';

hsl2hex([0, 100, 50]); // '#ff0000'
hsl2hex([200, 70, 50]); // '#269dd9'

hsl2rgb([0, 100, 50]); // [255, 0, 0]
hsl2rgb([0, 100, 50, 50]); // [255, 0, 0, 50]

hsl2hwb([0, 100, 50]); // [0, 0, 0]
hsl2oklab([0, 100, 50]); // [0.627, 0.224, 0.125]
hsl2cmyk([0, 100, 50]); // [0, 100, 100, 0]

HWB Conversions

Convert from HWB (Hue, Whiteness, Blackness) array.

Array format: [hue, whiteness, blackness, alpha?]

• hue: 0–360 (degrees)
• whiteness: 0–100 (%)
• blackness: 0–100 (%)
• alpha (optional): 0–100

Syntax

hwb2hex(hwb: [hue, whiteness, blackness, alpha?]): string | undefined
hwb2rgb(hwb: [hue, whiteness, blackness, alpha?]): [red, green, blue, alpha?] | undefined
hwb2hsl(hwb: [hue, whiteness, blackness, alpha?]): [hue, saturation, lightness, alpha?] | undefined
hwb2oklab(hwb: [hue, whiteness, blackness, alpha?]): [lightness, a, b, alpha?] | undefined
hwb2cmyk(hwb: [hue, whiteness, blackness, alpha?]): [cyan, magenta, yellow, black, alpha?] | undefined

Return values:

• hwb2hex: HEX color string (e.g. '#ff0000')
• hwb2rgb: [red (0-255), green (0-255), blue (0-255)] or with alpha (0-100)
• hwb2hsl: [hue (0-360), saturation (0-100), lightness (0-100)] or with alpha (0-100)
• hwb2oklab: [lightness (0-1), a (-0.4 to 0.4), b (-0.4 to 0.4)] or with alpha (0-100)
• hwb2cmyk: [cyan (0-100), magenta (0-100), yellow (0-100), black (0-100)] or with alpha (0-100)

Example

import { hwb2hex, hwb2rgb, hwb2hsl, hwb2oklab, hwb2cmyk } from '@nextcss/color-tools';

hwb2hex([0, 0, 0]); // '#ff0000'
hwb2rgb([0, 0, 0]); // [255, 0, 0]
hwb2hsl([0, 0, 0]); // [0, 100, 50]
hwb2oklab([0, 0, 0]); // [0.627, 0.224, 0.125]
hwb2cmyk([0, 0, 0]); // [0, 100, 100, 0]

OKLab Conversions

Convert from OKLab (perceptual color space) array.

Array format: [lightness, a, b, alpha?]

• lightness: 0–1 (perceived brightness)
• a: −0.4 to 0.4 (green–red axis)
• b: −0.4 to 0.4 (blue–yellow axis)
• alpha (optional): 0–100

Syntax

oklab2hex(oklab: [lightness, a, b, alpha?]): string | undefined
oklab2rgb(oklab: [lightness, a, b, alpha?]): [red, green, blue, alpha?] | undefined
oklab2hsl(oklab: [lightness, a, b, alpha?]): [hue, saturation, lightness, alpha?] | undefined
oklab2hwb(oklab: [lightness, a, b, alpha?]): [hue, whiteness, blackness, alpha?] | undefined
oklab2cmyk(oklab: [lightness, a, b, alpha?]): [cyan, magenta, yellow, black, alpha?] | undefined

Return values:

• oklab2hex: HEX color string (e.g. '#ff0000')
• oklab2rgb: [red (0-255), green (0-255), blue (0-255)] or with alpha (0-100)
• oklab2hsl: [hue (0-360), saturation (0-100), lightness (0-100)] or with alpha (0-100)
• oklab2hwb: [hue (0-360), whiteness (0-100), blackness (0-100)] or with alpha (0-100)
• oklab2cmyk: [cyan (0-100), magenta (0-100), yellow (0-100), black (0-100)] or with alpha (0-100)

Example

import { oklab2hex, oklab2rgb, oklab2hsl, oklab2hwb, oklab2cmyk } from '@nextcss/color-tools';

oklab2hex([0.627, 0.224, 0.125]); // '#ff0000'
oklab2rgb([0.627, 0.224, 0.125]); // [255, 0, 0]
oklab2hsl([0.627, 0.224, 0.125]); // [0, 100, 50]
oklab2hwb([0.627, 0.224, 0.125]); // [0, 0, 0]
oklab2cmyk([0.627, 0.224, 0.125]); // [0, 100, 100, 0]

CMYK Conversions

Convert from CMYK (cyan, magenta, yellow, black) array.

Array format: [cyan, magenta, yellow, black, alpha?]

• cyan: 0–100
• magenta: 0–100
• yellow: 0–100
• black: 0–100
• alpha (optional): 0–100

Syntax

cmyk2hex(cmyk: [cyan, magenta, yellow, black, alpha?]): string | undefined
cmyk2rgb(cmyk: [cyan, magenta, yellow, black, alpha?]): [red, green, blue, alpha?] | undefined
cmyk2hsl(cmyk: [cyan, magenta, yellow, black, alpha?]): [hue, saturation, lightness, alpha?] | undefined
cmyk2hwb(cmyk: [cyan, magenta, yellow, black, alpha?]): [hue, whiteness, blackness, alpha?] | undefined
cmyk2oklab(cmyk: [cyan, magenta, yellow, black, alpha?]): [lightness, a, b, alpha?] | undefined

Return values:

• cmyk2hex: HEX color string (e.g. '#ff0000')
• cmyk2rgb: [red (0-255), green (0-255), blue (0-255)] or with alpha (0-100)
• cmyk2hsl: [hue (0-360), saturation (0-100), lightness (0-100)] or with alpha (0-100)
• cmyk2hwb: [hue (0-360), whiteness (0-100), blackness (0-100)] or with alpha (0-100)
• cmyk2oklab: [lightness (0-1), a (-0.4 to 0.4), b (-0.4 to 0.4)] or with alpha (0-100)

Example

import { cmyk2hex, cmyk2rgb, cmyk2hsl, cmyk2hwb, cmyk2oklab } from '@nextcss/color-tools';

cmyk2hex([0, 100, 100, 0]); // '#ff0000'
cmyk2rgb([0, 100, 100, 0]); // [255, 0, 0]
cmyk2hsl([0, 100, 100, 0]); // [0, 100, 50]
cmyk2hwb([0, 100, 100, 0]); // [0, 0, 0]
cmyk2oklab([0, 100, 100, 0]); // [0.627, 0.224, 0.125]

Additional Functions

Useful tools for color manipulation, including brightness shifting, tone mapping, and random color generation.

Color Shift

Shift the brightness of a color by a percentage. Positive values lighten, negative values darken. Four implementations available using different color spaces — choose based on perceptual needs.

RGB Color Shift

Shift using RGB color space.

Syntax

rgbColorShift(hex: string, percentage: number): string | undefined

Parameters:

• hex (string): Input color in HEX format
• percentage (number): Brightness shift in range -100 to 100
  • Positive values: lighten the color
  • Negative values: darken the color

Example

import { rgbColorShift } from '@nextcss/color-tools';

rgbColorShift('#eee', 10); // '#f5f5f5' (lighter)
rgbColorShift('#eee', -10); // '#e5e5e5' (darker)

HSL Color Shift

Shift using HSL color space.

Syntax

hslColorShift(hex: string, percentage: number): string | undefined

Parameters:

• hex (string): Input color in HEX format
• percentage (number): Lightness shift in range -100 to 100
  • Positive values: lighten the color
  • Negative values: darken the color

Example

import { hslColorShift } from '@nextcss/color-tools';

hslColorShift('#2196f3', 20); // lighter
hslColorShift('#2196f3', -20); // darker

HWB Color Shift

Shift using HWB color space.

Syntax

hwbColorShift(hex: string, percentage: number): string | undefined

Parameters:

• hex (string): Input color in HEX format
• percentage (number): Brightness shift in range -100 to 100
  • Positive values: lighten the color
  • Negative values: darken the color

Example

import { hwbColorShift } from '@nextcss/color-tools';

hwbColorShift('#2196f3', 15); // lighter
hwbColorShift('#2196f3', -15); // darker

OKLab Color Shift

Shift using OKLab (best for perceptually uniform results).

Syntax

oklabColorShift(hex: string, percentage: number): string | undefined

Parameters:

• hex (string): Input color in HEX format
• percentage (number): Brightness shift in range -100 to 100
  • Positive values: lighten the color
  • Negative values: darken the color

Example

import { oklabColorShift } from '@nextcss/color-tools';

oklabColorShift('#2196f3', 15); // perceptually lighter
oklabColorShift('#2196f3', -15); // perceptually darker

Tone Map

Generate a complete tonal scale from a base color. Returns an object with tone steps (50–950) mapped to HEX color strings.

Syntax

toneMap(
  hex: string,
  mode?: 'rgb' | 'hsl' | 'hwb' | 'oklab',
  customTones?: Partial<Record<50 | 100 | 150 | 200 | 250 | 300 | 350 | 400 | 450 | 500 | 550 | 600 | 650 | 700 | 750 | 800 | 850 | 900 | 950, number>>
): Record<string, string> | undefined

Parameters:

• hex (string): Base color in HEX format
• mode (optional): Color space for interpolation — 'rgb' | 'hsl' | 'hwb' | 'oklab' (default: 'rgb')
• customTones (optional): Override default tone shift percentages.
  • Object with numeric tone step keys (any number, e.g. 50, 100, 150, ..., 950, or custom values) and color shift percentages (-100 to 100) as values.
  • Each value determines how much to lighten or darken the base color for that tone step.
  • If omitted, uses default tone steps (50, 100, 150, ..., 950) with default percentages: [90, 85, 74, 62, 50, 40, 30, 20, 10, 0, -11, -23, -34, -45, -56, -68, -79, -90, -97]

Example

import { toneMap } from '@nextcss/color-tools';

// Default tone map (uses default shift percentages)
const tones = toneMap('#2196f3');
console.log(tones);
// {
//   50: '#e3f2fd',   (tone 50, +90% lighter)
//   100: '#bbdefb',  (tone 100, +85% lighter)
//   150: '#90caf9',
//   ...
//   500: '#2196f3',  (tone 500, no shift)
//   ...
//   950: '#0d47a1'   (tone 950, -97% darker)
// }

// Using OKLab for better perceptual uniformity
const tonesOklab = toneMap('#2196f3', 'oklab');

// Custom shift percentages for specific tones
const customTonesMap = toneMap('#2196f3', 'hsl', {
  50: 95, // extra light (instead of default 90)
  100: 80, // slightly less light (instead of default 85)
  500: 0, // exact base color
  950: -95, // extra dark (instead of default -97)
});

// Custom tone steps (not limited to standard 50, 100, 150... 950)
const customStepsMap = toneMap('#2196f3', 'oklab', {
  0: 100, // lightest
  10: 80,
  20: 50,
  30: 0, // base color at step 30
  40: -50,
  50: -100, // darkest
});

Brightness

Calculate the perceived brightness of a color as a percentage (0–100). Useful for determining text contrast or applying adaptive styling.

Syntax

brightness(hex: string): number | undefined

Example

import { brightness } from '@nextcss/color-tools';

brightness('#000000'); // 0 (darkest)
brightness('#ffffff'); // 100 (lightest)
brightness('#269dd9'); // ~53 (neutral)

// Use for contrast decisions
if (brightness(color) < 50) {
  textColor = '#ffffff'; // light text on dark bg
} else {
  textColor = '#000000'; // dark text on light bg
}

Colorify

Generate a consistent, deterministic color from any string input (e.g., usernames, IDs). Outputs the same color for the same input every time.

Syntax

colorify(
  str: string,
  saturation?: number,
  lightness?: number,
  alpha?: number
): string | undefined

Parameters:

• str (string): Input string
• saturation (optional): 0–100 (default: 50)
• lightness (optional): 0–100 (default: 50)
• alpha (optional): 0–100 (default: 100)

Example

import { colorify } from '@nextcss/color-tools';

colorify('alice@example.com'); // '#40bf79' (consistent)
colorify('bob@example.com'); // '#ff6b9d' (different)

// Adjust saturation for muted tones
colorify('user123', 30); // lower saturation

// Custom lightness and alpha
colorify('dark-mode', 60, 30, 80); // dark with 80% opacity

// Same input always produces same color
colorify('alice') === colorify('alice'); // true

Random Colors

Generate random colors in any format. All random functions accept optional saturation, lightness, and alpha parameters.

Random HEX

Syntax

randomHex(saturation?: number, lightness?: number, alpha?: number): string | undefined

Parameters:

• saturation (optional): 0–100 (default: 70)
• lightness (optional): 0–100 (default: 50)
• alpha (optional): 0–100

Example

import { randomHex } from '@nextcss/color-tools';

randomHex(); // '#7de889' (random)
randomHex(50); // with saturation
randomHex(65, 80); // with saturation + lightness
randomHex(65, 80, 50); // with alpha (50%)

Random RGB

Syntax

randomRgb(saturation?: number, lightness?: number, alpha?: number): [red, green, blue, alpha?] | undefined

Parameters:

• saturation (optional): 0–100 (default: 70)
• lightness (optional): 0–100 (default: 50)
• alpha (optional): 0–100

Example

import { randomRgb } from '@nextcss/color-tools';

randomRgb(); // [232, 193, 125]
randomRgb(50); // with saturation
randomRgb(65, 80); // with saturation + lightness
randomRgb(65, 80, 50); // with alpha (50%)

Random HSL

Syntax

randomHsl(saturation?: number, lightness?: number, alpha?: number): [hue, saturation, lightness, alpha?] | undefined

Parameters:

• saturation (optional): 0–100 (default: 70)
• lightness (optional): 0–100 (default: 50)
• alpha (optional): 0–100

Example

import { randomHsl } from '@nextcss/color-tools';

randomHsl(); // [294, 70, 50]
randomHsl(50); // with saturation
randomHsl(65, 80); // with saturation + lightness
randomHsl(65, 80, 50); // with alpha (50%)

Random HWB

Syntax

randomHwb(saturation?: number, lightness?: number, alpha?: number): [hue, whiteness, blackness, alpha?] | undefined

Parameters:

• saturation (optional): 0–100 (default: 70)
• lightness (optional): 0–100 (default: 50)
• alpha (optional): 0–100

Example

import { randomHwb } from '@nextcss/color-tools';

randomHwb(); // [45, 10, 20]
randomHwb(60, 50, 75); // with parameters

Random OKLab

Syntax

randomOklab(saturation?: number, lightness?: number, alpha?: number): [lightness, a, b, alpha?] | undefined

Parameters:

• saturation (optional): 0–100 (default: 70)
• lightness (optional): 0–100 (default: 50)
• alpha (optional): 0–100

Example

import { randomOklab } from '@nextcss/color-tools';

randomOklab(); // [0.627, 0.224, 0.125]
randomOklab(70, 50, 90); // with parameters

Random CMYK

Syntax

randomCmyk(saturation?: number, lightness?: number, alpha?: number): [cyan, magenta, yellow, black, alpha?] | undefined

Parameters:

• saturation (optional): 0–100 (default: 70)
• lightness (optional): 0–100 (default: 50)
• alpha (optional): 0–100

Example

import { randomCmyk } from '@nextcss/color-tools';

randomCmyk(); // [0, 100, 100, 0]
randomCmyk(70, 50, 90); // with parameters

Guidelines

See the project Code of Conduct, Contributing, and Security Policy for details.

License

MIT License © 2022 Zsolt Tövis

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