cie.js

Node.js wrapper around CIE.sh.

📕 TOC

• 📃 About
  • 📦 Dependencies
• 🛠 Usage
  • 🖥 CLI
  • 🐳 CLI by Docker
  • 📄 Javascript
• 🔗 API
  • 1976 Formula
  • 1994 Formula
  • 2000 Formula
• 🎉 Acknowledgements
• 🥝 Lisence

📃 About

This package calculates the color difference between two colors using the color difference formula in LAB Delta E established by the Commission internationale de l'éclairage (CIE).
It also uses Bash Script for the main logic, so the following is required to run it.

📦 Dependencies

• bash >= 5.0
• grep
• awk
• sed
• cat
• bc

🛠 Usage

🖥 CLI

$ yarn global add cie.js  # npm install -g cie.js

$ cie-js -h
Usage: cie-js [options] [command]

Derives the color difference using the method defined by LAB Delta E (CIE76, CIE94, CIEDE2000).

Options:
  -v, --version   Output the version number
  -h, --help      display help for command

Commands:
  dE76            Use the CIE 1976 color difference formula.
  dE94            Use the CIE 1994 color difference formula.
  dE00            Use the CIEDE2000 color difference formula.
  help [command]  display help for command

TL;DR
  $ cie-js dE76 50.0000 2.6772 \ -79.7751 50.0000 0.0000 \ -82.7485
  $ cie-js dE94 -g 50.0000 2.6772 \ -79.7751 50.0000 0.0000 \ -82.7485
  $ cie-js dE00 50.0000 2.6772 \ -79.7751 50.0000 0.0000 \ -82.7485
  $ echo 50.0000,2.6772,-79.7751,50.0000,0.0000,-82.7485 | cie-js dE94 -t

$ cie-js dE76 50.0000 2.6772 \ -79.7751 50.0000 0.0000 \ -82.7485
4.0011
$ cie-js dE94 -g 50.0000 2.6772 \ -79.7751 50.0000 0.0000 \ -82.7485
1.3950

# Read from file
$ cat example.txt
50.0000 2.6772 -79.7751 50.0000 0.0000 -82.7485
50.0000 3.1571 -77.2803 50.0000 0.0000 -82.7485
50.0000 2.8361 -74.0200 50.0000 0.0000 -82.7485
50.0000 -1.3802 -84.2814 50.0000 0.0000 -82.7485
50.0000 -1.1848 -84.8006 50.0000 0.0000 -82.7485
50.0000 -0.9009 -85.5211 50.0000 0.0000 -82.7485

$ cat example.txt | cie-js dE76
4.0011
6.3142
9.1777
2.0627
2.3696
2.9153

🐳 CLI by Docker

# Install
$ docker pull ghcr.io/redpeacock78/cie.js

# Write the following function in .bashrc etc.
cie-js() {
  [[ -t 0 ]] && T="t" || T=""
  docker run -i"${T}" --rm ghcr.io/redpeacock78/cie.js:latest "${@}"
}

# Run!
$ source ~/.bashrc
$ cie-js dE76 50.0000 2.6772 \ -79.7751 50.0000 0.0000 \ -82.7485
4.0011

# Update
$ docker pull ghcr.io/redpeacock78/cie.js && docker rmi -f $(docker images | grep ghcr.io/redpeacock78/cie.js | grep none | awk '{print $3}')

# Uninstall
$ docker rmi -f $(docker images | grep ghcr.io/redpeacock78/cie.js | grep latest | awk '{print $3}')

📄 Javascript

import * as lab from 'cie.js'; // const lab = require('cie.js');

const color_1 = { L: 50.0000, a: 50.0000, b: 0.0000 };
const color_2 = { L: 40.0000, a: 50.0000, b: 0.0000 };
(async () => {
  await lab.dE76(color_1, color_2).then((result) => {
    console.log(result);
  })
})();
// => 10.0000

🔗 API

1976 Formula

The CIE 1976 color difference formula is the first color difference formula defined, and is calculated as the Euclidean distance in CIELAB coordinates.

• lab.dE76(color_1: {[key: string]: number}, color_2: {[key: string]: number}): Promise<string>

  const color_1 = { L: 50.0000, a: 2.6772, b: -79.7751 };
  const color_2 = { L: 50.0000, a: 0.0000, b: -82.7485 };
  (async () => {
    console.log(await lab.dE76(color_1, color_2));
  })();
  // => 4.0011

1994 Formula

ΔE(1994) is calculated from the difference in brightness, saturation, and hue in the L*C*h* color space, which is calculated from the L*a*b* color space. It also introduces a weighting factor for specific applications, derived from the allowable values for automotive paints.

• lab.dE94.textile(color_1: {[key: string]: number}, color_2: {[key: string]: number}): Promise<string>
  

  const color_1 = { L: 50.0000, a: 2.6772, b: -79.7751 };
  const color_2 = { L: 50.0000, a: 0.0000, b: -82.7485 };
  (async () => {
    console.log(await lab.dE94.textile(color_1, color_2));
  })();
  // => 1.4230

• lab.dE94.graphicArts(color_1: {[key: string]: number}, color_2: {[key: string]: number}): Promise<string>
  

  const color_1 = { L: 50.0000, a: 2.6772, b: -79.7751 };
  const color_2 = { L: 50.0000, a: 0.0000, b: -82.7485 };
  (async () => {
    console.log(await lab.dE94.graphicArts(color_1, color_2));
  })();
  // => 1.3950

2000 Formula

Since the CIE 1994 definition did not sufficiently ensure perceived uniformity, the CIE revised the definition and established the standard.

• lab.dE00(color_1: {[key: string]: number}, color_2: {[key: string]: number}): Promise<string>

  const color_1 = { L: 50.0000, a: 2.6772, b: -79.7751 };
  const color_2 = { L: 50.0000, a: 0.0000, b: -82.7485 };
  (async () => {
    console.log(await lab.dE00(color_1, color_2));
  })();
  // => 2.0425

🎉 Acknowledgements

• JavaScriptでCIE94色差計算 - Qiita
• JavaScriptでCIEDE2000色差計算 - Qiita
• 色の距離(色差)の計算方法 ‒ Qiita
• 色差 - Wikipedia
• Color Difference Calculator
• Gaurav Sharma
• 色差計算器 (CIE76, CIE2000) ‒ でじたる小屋

🥝 Lisence

MIT