Khrôma

A collection of functions for manipulating CSS colors, inspired by SASS.

Features

- Small: the entire library weighs ~5kb (min + gzip) and has no dependencies.
- Fast: in our benchmark suite functions are executed at ~0.0025ms per call on a mid-2014 MBP.
- Flexible: All valid CSS colors are supported.
- SASS-like: if you're familiar with SASS you should feel right at home.

Install

``sh
npm install --save khroma
`

Usage

`ts
import {red, isDark, darken, change} from 'khroma';

red ( '#ffffff' ); // => 255
isDark ( 'white' ); // => false
darken ( 'hsl(0, 5%, 100%)', 50 ); // => 'hsl(0, 5%, 50%)'
change ( 'rgb(255, 255, 255)', { a: 0.5 } ); // => 'rgba(255, 255, 255, 0.5)'
`

Functions

These are all the provided functions, for each of them below you can find a short description, its interface and examples.

| Create | Convert | Get channel | Get more | Edit channel | Edit more |
| ------------- | ----------------------- | ------------------------- | ------------------------------- | --------------------------------- | -------------------- |
| hex | toKeyword | channel | contrast | saturate | adjust |
| rgb | toHex | red | luminance | desaturate | change |
| rgba | toRgba | green | isDark | lighten | invert |
| hsl | toHsla | blue | isLight | darken | mix |
| hsla | | hue | isTransparent | opacify | scale |
| | | saturation | isValid | fadeIn | |
| | | lightness | | transparentize | |
| | | alpha | | fadeOut | |
| | | opacity | | rgba (alt) | |
| | | | | complement | |
| | | | | grayscale | |

$3

These functions create a new color given the provided channels.

#### hex

Alias for rgba.

#### rgb

Alias for rgba.

#### rgba

Creates a new color given its rgba channels, the alpha channel is optional.

`ts
function rgba ( r: string, g: number, b: number, a: number = 1 ): string;
`

`ts
rgba ( 255, 204, 0 ); // => '#ffcc00'
rgba ( 255, 204, 0, 0.5 ); // => 'rgba(255, 204, 0, 0.5)'
`

#### hsl

Alias for hsla.

#### hsla

Creates a new color given its hsla channels, the alpha channel is optional.

`ts
function hsla ( h: number, s: number, l: number, a: number = 1 ): string;
`

`ts
hsla ( 0, 50, 100 ); // => 'hsl(0, 50%, 100%)'
hsla ( 10, 50, 100, 0.5 ); // => 'hsla(10, 50%, 100%, 0.5)'
`

$3

These functions convert supported colors to a specific format.

#### toKeyword

Convert a color to the keyword format, when possible.

`ts
function toKeyword ( color: string ): string | undefined;
`

`ts
toKeyword ( '#ff0000' ); // => 'red'
toKeyword ( '#ffcc00' ); // => undefined
`

#### toHex

Convert a color to the HEX format.

`ts
function toHex ( color: string ): string;
`

`ts
toHex ( 'red' ); // => '#ff0000'
toHex ( '#ff0000' ); // => '#ff0000'
`

#### toRgba

Convert a color to the RGBA format.

`ts
function toRgba ( color: string ): string;
`

`ts
toRgba ( 'red' ); // => 'rgb(255, 0, 0)'
toRgba ( '#ff0000' ); // => 'rgb(255, 0, 0)'
toRgba ( '#00000088' ); // => 'rgba(0, 0, 0, 0.5333333333)'
`

#### toHsla

Convert a color to the HSLA format.

`ts
function toHsla ( color: string ): string;
`

`ts
toHsla ( 'red' ); // => 'hsl(0, 100%, 50%)'
toHsla ( '#ff0000' ); // => 'hsl(0, 100%, 50%)'
toHsla ( 'rgb(255, 0, 0)' ); // => 'hsl(0, 100%, 50%)'
`

$3

These functions get a single channel from the provided color.

#### channel

Gets any single channel of the color.

`ts
function channel ( color: string, channel: 'r' | 'g' | 'b' | 'h' | 's' | 'l' | 'a' ): number;
`

`ts
channel ( '#ffcc00', 'r' ); // => 255
channel ( '#ffcc00', 'h' ); // => 48
channel ( '#ffcc00', 'a' ); // => 1
`

#### red

Gets the red channel of the color.

`ts
function red ( color: string ): number;
`

`ts
red ( '#ffcc00' ); // => 255
`

#### green

Gets the green channel of the color.

`ts
function green ( color: string ): number;
`

`ts
green ( '#ffcc00' ); // => 204
`

#### blue

Gets the blue channel of the color.

`ts
function blue ( color: string ): number;
`

`ts
blue ( '#ffcc00' ); // => 0
`

#### hue

Gets the hue channel of the color.

`ts
function hue ( color: string ): number;
`

`ts
hue ( 'hsl(0, 50%, 100%)' ); // => 0
`

#### saturation

Gets the saturation channel of the color.

`ts
function saturation ( color: string ): number;
`

`ts
saturation ( 'hsl(0, 50%, 100%)' ); // => 50
`

#### lightness

Gets the lightness channel of the color.

`ts
function lightness ( color: string ): number;
`

`ts
lightness ( 'hsl(0, 50%, 100%)' ); // => 100
`

#### alpha

Gets the alpha channel of the color.

`ts
function alpha ( color: string ): number;
`

`ts
alpha ( '#ffcc00' ); // => 1
alpha ( 'rgba(255, 205, 0, 0.5)' ); // => 0.5
`

#### opacity

Alias for alpha.

$3

These functions get some other information from the provided color.

#### contrast

Gets the contrast in luminance between two colors.

Contrast values go between 1 and 10. 1 means same color, >= 4 means decent contrast, >= 7 means great contrast, 10 means great contrast.

`ts
function contrast ( color1: string, color2: string ): number;
`

`ts
contrast ( '#000000', '#000000' ); // => 1
contrast ( '#000000', '#ffffff' ); // => 10
contrast ( '#888888', '#ffffff' ); // => 4.0617165366
`

#### luminance

Gets the relative luminance of the color.

`ts
function luminance ( color: string ): number;
`

`ts
luminance ( 'black' ); // => 0
luminance ( 'white' ); // => 1
luminance ( '#ffcc00' ); // => 0.6444573127
`

#### isDark

Checks if the provided color is a dark color.

`ts
function isDark ( color: string ): number;
`

`ts
isDark ( 'black' ); // => true
isDark ( 'white' ); // => false
isDark ( '#ffcc00' ); // => false
`

#### isLight

Checks if the provided color is a light color.

`ts
function isLight ( color: string ): number;
`

`ts
isLight ( 'black' ); // => false
isLight ( 'white' ); // => true
isLight ( '#ffcc00' ); // => true
`

#### isTransparent

Checks if the provided color is a transparent color.

`ts
function isTransparent ( color: string ): boolean;
`

`ts
isTransparent ( 'transparent' ); // => true
isTransparent ( '#ffcc0000' ); // => true
isTransparent ( '#ffcc00' ); // => false
`

#### isValid

Checks if the provided color is a valid color.

`ts
function isLight ( color: string ): boolean;
`

`ts
isValid ( 'black' ); // => true
isValid ( '#ffcc00' ); // => true
isValid ( '#wtf' ); // => false
`

$3

These functions change a single channel of the provided color.

#### saturate

Increases the saturation channel of the color.

`ts
function saturate ( color: string, amount: number ): string;
`

`ts
saturate ( 'hsl(0, 50%, 50%)', 25 ); // => 'hsl(0, 75%, 50%)'
`

#### desaturate

Decreases the saturation channel of the color.

`ts
function desaturate ( color: string, amount: number ): string;
`

`ts
desaturate ( 'hsl(0, 50%, 50%)', 25 ); // => 'hsl(0, 25%, 50%)'
`

#### lighten

Increases the lightness channel of the color.

`ts
function lighten ( color: string, amount: number ): string;
`

`ts
lighten ( 'hsl(0, 50%, 50%)', 25 ); // => 'hsl(0, 50%, 75%)'
`

#### darken

Decreases the lightness channel of the color.

`ts
function darken ( color: string, amount: number ): string;
`

`ts
darken ( 'hsl(0, 50%, 50%)', 25 ); // => 'hsl(0, 50%, 25%)'
`

#### opacify

Increases the opacity channel of the color.

`ts
function opacify ( color: string, amount: number ): string;
`

`ts
opacify ( 'rgba(255, 204, 0, 0.5)', 0.25 ); // => 'rgba(255, 204, 0, 0.75)'
`

#### fadeIn

Alias for opacify.

#### transparentize

Decreases the opacity channel of the color.

`ts
function transparentize ( color: string, amount: number ): string;
`

`ts
transparentize ( 'rgba(255, 204, 0, 0.5)', 0.25 ); // => 'rgba(255, 204, 0, 0.25)'
`

#### fadeOut

Alias for transparentize.

#### rgba (alt)

Sets a new value for the opacity channel.

`ts
function rgba ( color: string, amount: number ): string;
`

`ts
rgba ( 'rgba(255, 204, 0, 0.5)', 0.1 ); // => 'rgba(255, 204, 0, 0.1)'
`

#### complement

Gets the complement of the color, rotating its hue channel by 180 degrees.

`ts
function complement ( color: string ): string;
`

`ts
complement ( '#ffcc00' ); // => 'hsl(228, 100%, 50%)'
`

#### grayscale

Gets the grayscale version of the color, setting its saturation to 0.

`ts
function grayscale ( color: string ): string;
`

`ts
grayscale ( '#ffcc00' ); // => 'hsl(48, 0%, 50%)'
`

$3

These functions can/will change more than a single channel at once of the provided color.

#### adjust

Increases or decreases the value of any channel of the color.

`ts
function adjust ( color: string, channels: Record<'r' | 'g' | 'b' | 'h' | 's' | 'l' | 'a', number> ): string;
`

`ts
adjust ( '#ffcc00', { r: -10, g: 200 } ); // => '#f5ff00'
adjust ( '#ffcc00', { a: -0.5 } ); // => 'rgba(255, 204, 0, 0.5)'
adjust ( '#ffcc00', { h: 50, l: -30 } ); // => 'hsl(98, 100%, 20%)'
`

#### change

Sets a new value for any channel of the color.

`ts
function change ( color: string, channels: Record<'r' | 'g' | 'b' | 'h' | 's' | 'l' | 'a', number> ): string;
`

`ts
change ( '#ffcc00', { r: 10, g: 200 } ); // => '#0ac800'
change ( '#ffcc00', { a: 0.5 } ); // => 'rgba(255, 204, 0, 0.5)'
change ( '#ffcc00', { h: 50, l: 30 } ); // => 'hsl(50, 100%, 30%)'
`

#### invert

Gets the inverse of the color.

`ts
function invert ( color: string, weight: number = 100 ): string;
`

`ts
invert ( '#ffcc00' ); // => '#0033ff'
invert ( '#ffcc00', 50 ); // => '#808080'
`

#### mix

Mixes two colors together.

`ts
function mix ( color1: string, color2: string, weight: number = 50 ): string;
`

`ts
mix ( 'red', 'blue' ); // => '#800080'
mix ( 'red', 'blue', 15 ); // => '#2600d9'
`

#### scale

Scales any channel of the color.

`ts
function scale ( color: string, channels: Record<'r' | 'g' | 'b' | 'h' | 's' | 'l' | 'a', number> ): string;
`

`ts
scale ( '#ffcc00', { r: -50, b: 10 } ); // => '#80cc1a'
``

License

MIT © Fabio Spampinato, Andrew Maney