better-color-tools

⚠️ Update Jun 2023

⚠️ This library is no longer maintained. Please use culori’s ESM build which delivers everything this library does, and then some, in the same bundlesize and at 5–10× performance.

Readme

JS and Sass color tools for the Oklab/Oklch colorspace for better color operations.

🏀 Playground

Usage

npm install better-color-tools

This library was created to provide performant and accurate access to the Oklab and Oklch colorspaces at minimum filesize and maximum performance. This is not a comprehensive colorspace tool like Culori or Color.js, rather, better-color-tools seeks to give you the best “bang for the buck” by providing maximum utility with minimal footprint.

To learn more, see Project Goals

JavaScript

Works in the browser (ESM) and Node (14+).

Importing

import better from 'better-color-tools';

Input

// CSS format
better.from('#b3f6e6'); // hex string
better.from('rebeccapurple'); // CSS keyword
better.from('rgb(136, 48, 62)'); // CSS sRGB
better.from('hsl(210, 85%, 37%)'); // CSS HSL
better.from('hwb(210, 6%, 31%)'); // CSS HWB
better.from('oklab(48.56949% -0.03971 -0.14459)'); // CSS Oklab
better.from('oklch(83.11253% 0.22612 147.35276)'); // CSS Oklch

// Other JS formats
better.from(0xb3f6e6); // hex integer (note: only mode that doesn’t support transparency)
better.from([0.533, 0.188, 0.243, 1]); // sRGB array/P3 (normalized to 1)
better.from({ r: 0.533, g: 0.188, b: 0.243, alpha: 1 }); // sRGB/P3 object (normalized to 1)
better.from({ h: 210, s: 0.85, l: 0.37, alpha: 1 }); // HSL object
better.from({ h: 210, w: 0.06, b: 0.31, alpha: 1 }); // HWB object
better.from({ l: 0.4856949, a: -0.03971, b: -0.14459, alpha: 1 }); // Oklab object (not CIELAB)
better.from({ l: 0.8311253, c: 0.22612, h: 147.35276, alpha: 1 }); // Oklch object (not CIELCh)

This library understands any CSS-valid color, including CSS Color Module 4* (but if some aspect isn’t implemented yet, please request it!).

* With the exception that lab() and lch() CSS Module 4 colors will be interpreted as oklab() and oklch(), respectively.

Playground

Output

This library converts to most web-compatible formats¹, with an emphasis on usefulness over completeness:

const c = better.from('rgba(136, 48, 62, 1)');

// CSS formats
c.hex; // #b3f6e6
c.rgb; // rgb(179, 246, 230) (note: will output rgba() if alpha < 1)
c.p3; // color(display-p3 0.701961 0.964706 0.901961)
c.linearRGB; // color(srgb-linear 0.450786 0.921582 0.791298)
c.oklab; // oklab(92.404387% -0.070395 0.002188)
c.oklch; // oklch(92.404387% 0.070429 178.219895)
c.xyz; // color(xyz-d65 0.658257 0.812067 0.870716)

// JS formats
c.hexVal; // 0xb3f6e6
const [r, g, b, alpha] = c.rgbVal; // [0.701961, 0.964706, 0.901961, 1]
const [r, g, b, alpha] = c.p3Val; // [0.701961, 0.964706, 0.901961, 1]
const [lr, lg, lb, alpha] = c.linearRGBVal; // [0.450786, 0.921582, 0.791298, 1]
const [l, a, b, alpha] = c.oklabVal; // [0.924044, -0.070395, 0.002188, 1]
const [l, c, h, alpha] = c.oklchVal; // [0.924044, 0.070429, 178.219895, 1]
const [x, y, z, alpha] = c.xyzVal; // [0.658257, 0.812067, 0.870716, 1]

¹The following formats aren’t supported as outputs:

• HSL isn’t supported because you shouldn’t use it
• HWB isn’t supported because it’s another form of HSL
• CIELAB/CIELCh aren’t supported because Oklab/Oklch are superior

For a comprehensive color conversion library, see Culori.

Adjust

To adjust a color via Oklch, append .adjust() along with the adjustments to make:

better.from('#0060ff').adjust({ lightness: 0.5 }); // set lightness to 50% (absolute)
better.from('#0060ff').adjust({ mode: 'relative', lightness: -0.1 }); // darken lightness by 10%

You can adjust lightness, chroma, and hue altogether, and you can either operate in relative or absolute (default) mode.

Note: adjustments may be chained together, but it’s worth noting that this library will always “snap” to the closest sRGB color with each adjustment. So chaining enough together, you may get different colors purely due to rounding errors. Prefer fewer chained adjustments (or keep the original color around) for best results.

P3

This library supports P3 by expanding the sRGB space into the P3 gamut 1:1. For example, 100% red sRGB is converted to 100% red P3:

const red = '#ff0000';
better.from(red).rgb; // rgb(255, 0, 0)
better.from(red).p3; // color(display-p3 1 0 0)

Playground

This is the practice recommended by WebKit because when dealing with web colors you probably intend to take full advantage of that expanded gamut and this is the easiest, quickest way to do so without dealing with the specifics of both the sRGB and P3 gamuts. This gives you more vibrant colors in supporting browsers without your colors appearing “off.”

While you wouldn’t want to use this technique for other methods such as photo manipulation, for CSS purposes this method is ideal (which better-color-tools assumes you’re using this for). Any deviation between this library’s implementation of P3 from others’ are intentional.

Mix

This uses Oklab (best) by default, but also supports oklch, lms, sRGB, and linearRGB colorspaces for mixing.

better.mix('red', 'lime', 0.35); // Mix `red` and `lime` 35%, i.e. more red
better.mix('blue', 'magenta', 0.5, 'linearRGB'); // Mix `blue` and `magenta` 50% using linearRGB colorspace

Playground

Lighten / Darken

This takes hue and human perception into account for visually-accurate results. Also, fun fact: both functions accept negative values.

better.lighten('red', 0.5); // Lighten color by 50%
better.darken('red', 0.5); // Darken color by 50%

Playground

Lightness

Get the human-perceived lightness of any color (this is an alias for .oklabVal[0])

better.lightness('#fc7030'); // 0.7063999

Playground

Contrast Ratio

Get WCAG 2.1 contrast ratio for 2 colors. The order doesn’t matter.

better.contrastRatio('#37ca93', '#055af6'); // { ratio: 2.4,   AA: false, AAA: false }
better.contrastRatio('#37ca93', '#4474cc'); // { ratio: 4.5,   AA: true,  AAA: false }
better.contrastRatio('#37ca93', '#002c7b'); // { ratio: 12.76, AA: true,  AAA: true }

Light or dark?

Should you overlay white or black text over a color? This will figure out whether a color is perceptually “dark” or “light,” taken directly from Myndex’s “flip for color” technique. You can then use white text for dark colors, and vice-versa.

Note: though it would be reasonable to assume this just checks whether Oklab’s l (lightness) value is over or under 0.5, there’s a bit more to it)

better.lightOrDark('#2d659e'); // "dark" (white text will show better)
better.lightOrDark('#b2d6d3'); // "light" (black text will show better)

Optimizing use in JS Frameworks (React, Svelte, etc.)

For most usecases, this library can be used in any JS framework without the need for memoization or caching.

However, if you need to optimize usage, it’s important to know:

• better.from() will parse the color each time, and create a new internal cache for all subsequent colorspace operations for that color.
• Colorspace transforms (e.g. color.oklab) are all getters that only transform the color when requested (so no work is wasted). Further, it uses the internal cache, so subsequent calls are memoized.

In practical terms, optimal usage only requires caching the better.from() call and nothing else. Here are some examples of optimized code with a color prop:

React

import better from 'better-color-tools';
import React, { useMemo } from 'react';

function MyComponent({ color }: { color: string }) {
  const myColor = useMemo(() => better.from(color), [color]);

  return <div>{myColor.oklab}</div>;
}

Svelte

<script type"ts">
  import better from 'better-color-tools';

  export let color: string;

  $: myColor = better.from(color);
</script>

<div>{myColor.oklab}</div>

In both instances, saving the output of better.from() is all that’s needed to preserve the internal cache so that subsequent renders require no work if the base color hasn’t changed. Further optimizations are unnecessary. But again, this library will usually perform faster than most other color transformations anyway, so in most instances, this library will be one of the last things slowing your code down.

Sass

Works with any version of Dart Sass (the current version).

Importing

@use 'better-color-tools' as better;

Mix

.foo {
  color: better.mix('red', 'lime', 0.35);
}

Uses Oklab for best results (which yields much better results than Sass’ mix).

Lighten / Darken

.foo:hover {
  color: better.lighten('blue', 0.2);
  border-color: better.darken('blue', 0.15);
}

Lightens (or darkens) color via Oklab for human-perceived lightness value (which yields much better results than Sass’ lighten/darken:

P3

.foo {
  color: better.p3(#f00); // color(display-p3 1 0 0)
}

Convert any Sass-readable color to P3.

Fallback

.foo {
  @include better.fallback('color', better.p3(#f00), #f00);
  // color: #f00;
  // color: color(display-p3 1 0 0);
}

Mixin for adding CSS fallbacks. Can take infinite arguments. Specify desired format first, followed by fallbacks.

Oklab/Oklch

$oklab: better.rgbToOklab(#f00); // (l: 0.6279554, a: 0.22486, b: 0.12585)
$oklch: better.rgbToOklch(#f00); // (l: 0.6279554, c: 0.25769, h: 29.23389)
$rgb: better.oklabToRGB($oklab); // #f00
$rgb: better.oklchToRGB($oklch); // #f00

Converts any Sass-readable color to an Oklab map of (l: …, a: …, b: …), or Oklch map of (l: …, c: …, h: …). The Sass map can either be used to make a CSS string:

@use 'sass:map';

.foo {
  color: oklab(#{map.get($oklab, 'l')} #{map.get($oklab, 'a')} #{map.get($oklab, 'b')});
  color: better.oklabToRGB($oklab); // fallback
}

Or for color manipulation:

$oklab-lighter: map.set($oklab, 'l', 0.8);

Lightness

Get the human-perceived lightness of any color (identical to the first value of .oklabVal):

$lightness: better.lightness(#f00);