color-lite v1.0.0 — the color management library

Supports parsing and convenient handling of RGB(A) and HSL(A) color representations. Provides pretty same interface for color manipulations as LESS/SASS does.
Read more about RGB and HSL.

First,

npm install --save color-lite

then use it as a module in your JS code:

const Color = require('color-lite');
const c1 = new Color(30, 50, 70, .9);
const c2 = new Color('hsla(140, 75%, 30%, .2)');
const c3 = new Color({h: 20, s: 35, l: 90, a: 1});

document.querySelector('.header').style.backgroundColor = c1.toString();
document.querySelector('.footer').style.backgroundColor = c1.clone().tune({l: -20}).toString(); // a bit lighter
c3.set({a: .5}).toString(Color.HSLA); // "hsla(20, 35%, 90%, .5)"

Constructor

Use new Color(...) to create the color instance.

Parameters:

• either the Object with properties corresponding to each channel, for instance,
  new Color({r: 100, g: 150, b: 300}),
  new Color({h: 235, s: 30, l: 65, a: .85}),
• or the String representation (like in CSS):
  new Color("rgba(200, 30, 21, 0.5)"),
  new Color("hsl(70, 50%, 35%)"),
  new Color("#ab84e3").
  • The string must be correct:
    • if you pass, for instance, "rgba(...)", we expect 4 arguments in parentheses.
    • Don't forget % for HSL(A) strings!
  • Both "#abcdef" and "#abc" representations are supported (case-insensitive).
  • Extra spaces are ignored;
• or the sequence of Numbers: (considered as RGB(A))
  new Color(180, 30, 75),
  new Color(85, 120, 175, .5).

If nothing parsable is provided, new Color() returns the instance of black: rgba(0, 0, 0, 1).

Normalization and channel defaults

Input values for channels are normalized:

• RGB values are normalized to 0..255;
• Hue is normalized to 0..359 respecting the color circle wrap-around (-30 is considered as 330; 400 is considered as 40);
• both Saturation and Lightness respect the range 0..100, not 0..1;
• Alpha channel is normalized to 0..1.

Default value for all the channels is 0 except of Alpha; it's 1 by default.

The color instance

Uses following params and methods:

• per-channel properties:
  • .r, .g, .b,
  • .h, .s, .l,
  • .a.
    Changing them directly affects the color. If you change RGB channels, HSL ones are updated accordingly (and vice versa). Channel constraints are respected:

const c = new Color(120, 200, 50);
c.toString(Color.RGB); // rgb(120, 200, 50)
c.toString(Color.HSL); // hsl(92, 60%, 49%)
c.h = 200;
c.toString(Color.RGB); // rgb(50, 150, 200)
c.toString(Color.HSL); // hsl(200, 60%, 49%)
c.b = 500; // too much
c.toString(Color.RGB); // rgb(50, 150, 255)
c.toString(Color.HSL); // hsl(211, 100%, 60%)

• .set(channels) method. It expects the Object (like {h: 30, s: 50, l: 90}) and sets the channel values accordingly.
  • Not all the channels are mandatory: .set({h: 30, a: .3}) is fine.
  • Never mix up RGB ans HSL channels in one object. If this happens, RGB channels are taken into consideration and HSL ones are ignored. console.warn() is emitted.
• .tune(channels) method. It behaves like .set() but expects the delta not the value: c1.tune({l: -20}) decreases the Lightness channel in 20 points.
  • Channel constraints are respected as well.
  • Both set() and .tune() return the reference to the object instance so they are chainable:
    c.set({a: .5}).tune({h: 180});
• .clone() returns the new clone of the Color instance (not the reference).
• .toString(type) returns the CSS-friendly value. type is one of static constants: Color.RGB, Color.RGBA, Color.HSL, Color.HSLA or Color.RGB_HEX (this is default).

const c = new Color(95, 5, 250);
c.toString(Color.RGBA); // rgba(95, 5, 250, 1)
c.toString(Color.HSL); // hsl(262, 96%, 50%)
c.toString(); // #5f05fa

Static constants

Color.RGB, Color.RGBA, Color.HSL, Color.HSLA and Color.RGB_HEX stand for color type constants. These ones are used for .toString().

Tips and tricks

• The HSL model is more human-friendly as the RGB.
• It speaks same language human beings do, for instance, it understands "make the color darker", or "make it more blue-ish".
  Such tricks done by the .tune() method:

const color = new Color('#af8c63');

// pay attention, without `.clone()` you'll change the original instance!
const darker = color.clone().tune({l: -20});
const lighter = color.clone().tune({l: 20});

const saturated = color.clone().tune({s: 30});
const desaturated = color.clone().tune({s: -30});

const opposite = color.clone().tune({h: 180});
const harmonical_01 = color.clone().tune({h: 120}); // or any other hue shift
const harmonical_02 = color.clone().tune({h: -120});

const totallyDifferent = color.clone().tune({h: 30, s: 40}).set({l: 50}); // the sequence might continue

document.body.style.backgroundColor = totallyDifferent.toString(); // "#d5db24"

• Pay attention, while converting RGB → HSL → RGB', channels in RGB and RGB' might differ a bit. That's ok due to necessity to round floats to integers. Such delta does not affect how the color is recognized by the human eye.
  Same happens by comparing results of two different RGB ↔ HSL converters.

Demo

Open the ./demo/demo.html to check the power of the library.

Changes since color.js#0.6.0

This library is successor of my project color.js (now discontinued). So what's new:

• Constructor and entry point renamed: $color(...) → Color(...).
• No more per-type constructors:
  $color.rgb(...) → Color(...);
  $color.hsla(...) → Color(...).
• No more per-type properties, setters and tuner: color.set.r(..) → color.r = ...;.
• No more instance converters. All the channels are present in the instance:

// 0.6.0
const col_rgb = new $color.rgb('#dea');
const col_hsl = col_rgb.toHsl();

// 1.0.0
const col = new Color('#dea');
const { r, g, b } = col;
const { h, s, l, a } = col;

• Static props and methods changed.
• 100% ES6.
• No more memory leaks via clone/create!

Development

• we expect you to have the NodeJS. Do npm install;
• npm test for unit testing;
• npm run prod to generate color-lite.min.js;
• use color-lite.min.js in browser.

Support

The color-lite.min.js could be included in your HTML. In this case window.Color becomes globally accessible object. It works well with all modern browsers with ES6 support.

Credits

Roman Melnyk email.rom.melnyk@gmail.com