Color utilities

Collection of useful methods for colors parsing, validation, transformations and calculations. Exposed as a class, so can be used as a stand-alone, or inside Angular apps.

Install and use

npm install @radiatingstar/color-utilities

// TypeScript, JavaScript module
import {ColorUtilities} from '@rs/color-utilities'

// Node, browserify
var colorUtil = require('@rs/color-utilities')

Features

Parsers

Parse a hexadecimal color

#parseHexColor(color: hexColor): colorValues

Transforms a hexadecimal color into an array of RGB values in base-10.

Parameters

color - A hexadecimal color (eg. '#FFA500'). Shorthand notation ('#FFF') and small caps are also supported.

Returns

An array representation of the provided number. Throws if an invalid hex was used (use validators methods id unsure if the value will always be correct).

Examples

colorUtil.parseHexColor('#FFAA500') // => [255, 165, 0]
colorUtil.parseHexColor('#fff') // => [255, 255, 255]

Validators

Validate a hexadecimal color

#isValidHexColor(potentialHexColor?: hexColor): boolean

Checks if the provided color is a valid hexadecimal color.

Parameters

color - A hexadecimal color (eg. '#FFA500'). Shorthand notation ('#FFF') and small caps are also supported.

Returns

A boolean indicating validity of the color. For clarity sake: true means the color is valid.

Examples

colorUtil.isValidHexColor('#FFA500') // => true 
colorUtil.isValidHexColor('#fff') // => true
colorUtil.isValidHexColor('#QWERTY') // => false 
colorUtil.isValidHexColor('#123456789') // => false
colorUtil.isValidHexColor(null) // => false

Analyzers

Get the hexadecimal color's parts

#splitHexColor(color: hexColor): hexColorValues

Splits the hexadecimal color into an array of it's hexadecimal RGB values.

Parameters

color - A hexadecimal color (eg. '#FFA500'). Shorthand notation ('#FFF') and small caps are also supported. The return value is always normalized to uppercase two letters/numbers long values.

Returns

The result of this method is a 3 items long array of hexadecimal RGB values.

Examples

colorUtil.splitHexColor('#FFA500') // => ['FF', 'A5', '00']
colorUtil.splitHexColor('#fff') // => ['FF', 'FF', 'FF']

Normalizers

Normalize a hexadecimal color value

#normalizeHexColor(hexColor: hexColor): hexColor

Transforms a valid hex color into a uniform shape: 6 uppercased characters.

Parameters

color - A valid hex color that might be written in a shorthand notation or in lower case. As a bonus, this method considers the colors without initial '#' as semi-valid and adds the missing sign (validation still reports it's not a valid color).

Returns

A valid, 6 characters long (7 with '#') string of uppercased letters and numbers.

Examples

colorUtil.normalizeHexColor('#fff') // => ['FF', 'FF', 'FF']

Utilities

Calculate luminance of a color

#calculateLuminanceOf(color: hexColor): number

Calculates the relative luminance of a color, as defined in the W3C Specification.

Parameters

color - A valid hex color that might be written in a shorthand notation or in lower case.

Returns

A number representing the relative luminance in [0-1] range.

Examples

colorUtil.calculateLuminanceOf('#FFFFFF') // => 1
colorUtil.calculateLuminanceOf('#000000') // => 0
colorUtil.calculateLuminanceOf('#FFA500') // => 0.48170267036309633

Calculate contrast between two colors

#calculateContrastRatio(color1: hexColor, color2: hexColor): number

Calculates a contrast ratio between two colors, as defined in the W3C Specification.

Parameters

color1 - A valid hex color that might be written in a shorthand notation or in lower case. color2 - A valid hex color that might be written in a shorthand notation or in lower case.

Returns

A contrast between the provided colors. The value is in range [1-21].

Examples

colorUtil.calculateContrastRatio('#FFFFFF', '#000000') // => 21
colorUtil.calculateContrastRatio('#000000', '#000000') // => 1
colorUtil.calculateContrastRatio('#FFA500', '#000000') // => 11

License

MIT