postcss-color-function

postcss-color-function

PostCSS plugin to transform W3C CSS color function to more compatible CSS.

Installation

$ npm install postcss-color-function

Usage

// dependencies
var fs = require("fs")
var postcss = require("postcss")
var colorFunction = require("postcss-color-function")

// css to be processed
var css = fs.readFileSync("input.css", "utf8")

// process css
var output = postcss()
  .use(colorFunction())
  .process(css)
  .css

Using this input.css:

body {
  background: color(red a(90%))
}

you will get:

body {
  background: rgba(255, 0, 0, 0.9)
}

Checkout tests for examples.

Interface (according to CSS specs)

color( [ <color> | <hue> ] <color-adjuster>* )

List of color-adjuster

• [red( | green( | blue( | alpha( | a(] ['+' | '-']? [<number> | <percentage>] )
• [red( | green( | blue( | alpha( | a(] '*' <percentage> )
• rgb( ['+' | '-'] [<number> | <percentage>]{3} ) @todo
• rgb( ['+' | '-'] <hash-token> ) @todo
• rgb( '*' <percentage> ) | @todo
• [hue( | h(] ['+' | '-' | '*']? <angle> )
• [saturation( | s(] ['+' | '-' | '*']? <percentage> )
• [lightness( | l(] ['+' | '-' | '*']? <percentage> )
• [whiteness( | w(] ['+' | '-' | '*']? <percentage> )
• [blackness( | b(] ['+' | '-' | '*']? <percentage> )
• tint( <percentage> )
• shade( <percentage> )
• blend( <color> <percentage> [rgb | hsl | hwb]? )
• blenda( <color> <percentage> [rgb | hsl | hwb]? ) @todo
• contrast( <percentage>? )

Notes:

• some adjusts have shortcuts,
• can be used on every value on any property,
• some values can use add/subtract/scale modifiers or a direct value.

Read the specs for more information.

Examples

whatever {
  color: color(red a(10%);
  
  background-color: color(red lightness(50%)); /* == color(red l(50%)); */
  
  border-color: color(hsla(125, 50%, 50%, .4) saturation(+ 10%) w(- 20%));
}

FAQ

Can you support currentcolor so we can do color(currentcolor adjuster())?

No we cannot do that. currentcolor depends on the cascade (so the DOM) and we can't handle that in a simple preprocessing step. You need to handle that with polyfills.

Can we use CSS custom properties so we can do color(var(--mainColor) adjuster())?

By using postcss-custom-properties before this plugin, you can do that (sort of). You have some examples in cssnext playground.

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Contributing

Work on a branch, install dev-dependencies, respect coding style & run tests before submitting a bug fix or a feature.

$ git clone https://github.com/postcss/postcss-color-function.git
$ git checkout -b patch-1
$ npm install
$ npm test

Changelog

License

Changelog

1.2.0 - 2015-03-12

• Added: contrast() adjuster