color-diff

What is color-diff?

The color-diff npm package is used for color difference calculations and color palette reduction. It provides utilities to find the closest color match from a palette and to calculate the difference between colors using various algorithms.

What are color-diff's main functionalities?

Calculate Color Difference

This feature allows you to calculate the difference between two colors. The `diff` function takes two color objects and returns a numerical value representing the difference.

const colorDiff = require('color-diff');

const color1 = { R: 255, G: 0, B: 0 };
const color2 = { R: 0, G: 255, B: 0 };
const difference = colorDiff.diff(color1, color2);
console.log(difference);

Find Closest Color

This feature allows you to find the closest color from a given palette. The `closest` function takes a color object and a palette array, and returns the closest matching color from the palette.

const colorDiff = require('color-diff');

const palette = [
  { R: 255, G: 0, B: 0 },
  { R: 0, G: 255, B: 0 },
  { R: 0, G: 0, B: 255 }
];
const color = { R: 128, G: 128, B: 0 };
const closestColor = colorDiff.closest(color, palette);
console.log(closestColor);

Palette Reduction

This feature allows you to reduce a set of colors to a given palette. The `map_palette` function takes an array of colors and a palette, and returns a new array where each color is replaced by the closest color from the palette.

const colorDiff = require('color-diff');

const colors = [
  { R: 255, G: 0, B: 0 },
  { R: 0, G: 255, B: 0 },
  { R: 0, G: 0, B: 255 },
  { R: 128, G: 128, B: 0 }
];
const palette = [
  { R: 255, G: 0, B: 0 },
  { R: 0, G: 255, B: 0 }
];
const reducedColors = colorDiff.map_palette(colors, palette);
console.log(reducedColors);

Other packages similar to color-diff

color

The 'color' package provides a wide range of color manipulation and conversion utilities. It supports color conversion between different formats (RGB, HSL, etc.), color manipulation (lightening, darkening), and more. Compared to color-diff, it offers more comprehensive color manipulation features but does not focus on color difference calculations.

chroma-js

Chroma.js is a powerful library for color conversions and color scales. It supports a variety of color spaces and provides utilities for color interpolation, color scales, and color manipulation. While it offers some color difference calculations, its primary focus is on color manipulation and visualization, making it more versatile than color-diff in those areas.

tinycolor2

TinyColor is a small, fast library for color manipulation and conversion. It supports a variety of color formats and provides utilities for color blending, lightening, darkening, and more. Similar to the 'color' package, it offers extensive color manipulation features but does not specialize in color difference calculations like color-diff.

README

color-diff

Implements the CIEDE2000 color difference algorithm, conversion between RGB and LAB color and mapping all colors in palette X to the closest color in palette Y based on the CIEDE2000 difference.

Installation

npm install color-diff --save

Tests

Are located in the test/ folder and are run by:

npm test

Usage

// CommonJS
const { 
  closest, 
  furthest,
  diff, 
  mapPalette,
  paletteMapKey,
  rgbaToLab,
  mapPaletteLab,
  labPaletteMapKey,
} = require("color-diff");

// ESM
import {
  closest,
  furthest,
  diff,
  mapPalette,
  paletteMapKey,
  rgbaToLab,
  mapPaletteLab,
  labPaletteMapKey,
} from "color-diff";

closest(color, palette, bc)

Returns the closest color. The parameter bc is optional and is used as background color when the color and/or palette uses alpha channels.

const color = { R: 255, G: 1, B: 30 };
// red, green, blue
const palette = [ {R: 255, G: 0, B: 0 },
                {R: 0, G: 255, B: 0 },
                {R: 0, G: 0, B: 255} ];

closest(color, palette); // {R: 255, G: 0, B: 0 }, red

The result above is obvious, but diff.closest could deal with more complicated cases.

furthest(color, palette, bc)

Returns the most different color. The parameter bc is optional and is used as background color when the color and/or palette uses alpha channels.

const color = { R: 255, G: 255, B: 255 };
// black, white
const palette = [ {R: 0, G: 0, B: 0 }, {R: 255, G: 255, B: 255 } ];

furthest(color, palette); // {R: 0, G: 0, B: 0 }, black

The result above is obvious, but diff.furthest could deal with more complicated cases.

mapPalette(palette1, palette2)

Returns a mapping from the colors in palette1 to palette2.

paletteMapKey(color)

Return the palette map key for the color, to be used with the result from mapPalette.

diff(color1, color2, bc)

Returns the difference between the lab colors color1 and color2. The parameter bc is optional and is used as background color when one of the colors uses alpha channels.

rgba color

Object

RGBAColor is an object containing 4 properties: 'R', 'G', 'B', 'A', where 'A' is optional OR 'r', 'g', 'b', 'a', where 'a' is optional . Such as:

{ R: 255, G: 1, B: 0 }

There is an optional property 'A', which specifies the alpha channel between 0.0 and 1.0. If not present the color will be treated as fully opaque, i.e. A = 1.0.

Each RGBA-color is transformed into a RGB-color before being used to calculate the CIEDE2000 difference, using the specified background color (defaults to white).

lab color

Object

LabColor is an object containing 3 properties 'L', 'a', 'b' such as:

{ L: 100, a: 0.005, b: -0.010 }

palette

Array.<RGBAColor>

Color palette array which contains many RGBAColor objects.

Author

Markus Ekholm

License

3-clause BSD. For details see COPYING.

Changelog

1.4.0

• Use ESM modules. Backwards compatible with CJS using rollup.
• Replaced nyc with c8 (nyc does not support esm).