chroma-js

What is chroma-js?

chroma-js is a JavaScript library for color conversions and color scales. It provides a wide range of functionalities for color manipulation, including color creation, color scales, color interpolation, and color analysis.

What are chroma-js's main functionalities?

Color Creation

You can create colors using various input formats such as named colors, hex codes, RGB, HSL, etc. The example demonstrates creating a color from a named color and converting it to a hex code.

const chroma = require('chroma-js');
const color = chroma('red');
console.log(color.hex()); // #FF0000

Color Scales

Chroma-js allows you to create color scales that can interpolate between multiple colors. The example shows creating a grayscale scale and getting the color at the midpoint.

const chroma = require('chroma-js');
const scale = chroma.scale(['white', 'black']);
console.log(scale(0.5).hex()); // #808080

Color Interpolation

You can interpolate between two colors using chroma-js. The example demonstrates mixing red and blue to get a purple color.

const chroma = require('chroma-js');
const color1 = chroma('red');
const color2 = chroma('blue');
const interpolatedColor = chroma.mix(color1, color2, 0.5);
console.log(interpolatedColor.hex()); // #800080

Color Analysis

Chroma-js provides methods to analyze colors, such as getting the luminance. The example shows how to get the luminance of the color orange.

const chroma = require('chroma-js');
const color = chroma('orange');
console.log(color.luminance()); // 0.5

Other packages similar to chroma-js

color

The 'color' package is a JavaScript library for color conversion and manipulation. It supports a wide range of color models and provides methods for color transformations. Compared to chroma-js, it is more focused on color conversions and less on color scales and interpolation.

tinycolor2

TinyColor is a small color manipulation and conversion library. It provides similar functionalities to chroma-js, such as color creation, manipulation, and conversion. However, it is designed to be lightweight and may not have as extensive features for color scales and interpolation as chroma-js.

d3-color

d3-color is part of the D3.js library and provides color manipulation and conversion functionalities. It integrates well with other D3 modules for data visualization. While it offers similar color manipulation features, it is more commonly used within the context of D3 visualizations.

README

Chroma.js

Chroma.js is a tiny JavaScript library (14kB) for all kinds of color conversions and color scales.

Usage

Initiate and manipulate colors:

chroma('#D4F880').darken().hex();  // #9BC04B

Working with color scales is easy, too:

scale = chroma.scale(['white', 'red']);
scale(0.5).hex(); // #FF7F7F

Lab/Lch interpolation looks better than RGB

chroma.scale(['white', 'red']).mode('lab');

Custom domains! Quantiles! Color Brewer!!

chroma.scale('RdYlBu').domain(myValues, 7, 'quantiles');

And why not use logarithmic color scales once in your life?

chroma.scale(['lightyellow', 'navy']).domain([1, 100000], 7, 'log');

Like it?

Why not dive into the interactive documentation (there's a static version, too). You can download chroma.min.js or use the hosted version on cdnjs.com.

You can use it in node.js, too!

npm install chroma-js

Or you can use it in SASS using chromatic-sass!

Build instructions

First clone the repository and install the dev dependencies:

git clone [e-mail]:gka/chroma.js.git
cd chroma.js
npm install

Then compile the coffee-script source files to the build files:

npm run build

Don't forget to tests your changes! You will probably also want to add new test to the /test folder in case you added a feature.

npm test

And to update the documentation just run

npm run docs

To preview the docs locally you can use

npm run docs-preview

Similar Libraries / Prior Art

• Chromatist
• GrapeFruit (Python)
• colors.py (Python)
• d3.js

Author

Chroma.js is written by Gregor Aisch.

License

Released under BSD license. Versions prior to 0.4 were released under GPL.

Further reading

• How To Avoid Equidistant HSV Colors
• Mastering Multi-hued Color Scales with Chroma.js

FAQ

There have been no commits in X weeks. Is chroma.js dead?

No! It's just that the author of this library has other things to do than devoting every week of his life to making cosmetic changes to a piece of software that is working just fine as it is, just so that people like you don't feel like it's abandoned and left alone in this world to die. Bugs will be fixed. Some new things will come at some point. Patience.

Changelog

1.4.1

• chroma.scale() now interprets null as NaN and returns the fallback color. Before it had interpreted null as 0
• added scale.nodata() to allow customizing the previously hard-coded fallback (aka "no data") color #cccccc