readable-color

The project provides a function to determine a color that - according to established algorithms - should be easily readable on a given background.

Example use-case: You want to display text on a GUI element with an unknown background color f.ex. if the user can pick the color or if the color is generated from other values.

The project exposes four algorithms/methods:

• W3C (default if no method is specified): See http://www.w3.org/TR/AERT#color-contrast
• WCAG: See https://www.w3.org/WAI/WCAG22/Techniques/general/G18.html
• Luminosity: Simple 10% luminosity difference between foreground and background
• LuminosityContrast: See https://colorusage.arc.nasa.gov/luminance_cont.php

See demo at https://codepen.io/Michel-Albert/pen/eYxrXeG

The library shifts the "lightness" of the background-color until a readable value is found. If none is found, it will stop at either "full-black" or "full-white". This latter "cutoff" may lead to colors that are still unreadable in edge-cases, depending on the chosen method.

NOTE: The best results have so far been achieved with the W3C and WCAG methods. The others are still present for backwards-compatibility and reference.

Example:

import { getReadableColor } from "@exhuma/readable-color";

// Get a readable color with the default method.
const readableColor = getReadableColor("#123456");

// example using another method.
const anotherColor = getReadableColor("#123456", "WCAG");

const theElement = document.getElementById("my-element");
theElement.style.color = readableColor;

Development

To install dependencies:

npm install

To build:

npm run build

To run a dev-server:

npm run dev

Then access: http://localhost:5173/src/index.html