sweep.js

Status

This project is no longer maintained. CSS now has built-in support for setting color-interpolation-method. Transitioning through the oklch color space is a superior alternative to using this library.

About

sweep.js is a small JavaScript library (5kb zipped) that enables proper color transitions through the HSL and HUSL spaces. Ordinary CSS transitions and existing frameworks convert HSL colors to RGB before transitioning. sweep.js addresses this by letting you transition through the color spectrum.

I've written an in-depth post about the need for HSL transitions here.

Install

As a bundle:

bower install -S sweep

As a standalone library:

<script src="//cdn.jsdelivr.net/sweep/latest/mainfile"></script>

...or just visit the repo.

Sweep's dependencies are bundled; all you have to do is include the script. Sweep is wrapped with UMD, so it will also work as a module in your system of choice.

Usage

Using sweep.js to transition an element's color is easy. Whenever you want to trigger an HSL sweep, call:

sweep(target, properties, fromColor, toColor[, options]);

• target : element that you wish to animate
• properties : CSS properties that you wish to animate (string or array of strings)
• fromColor : initial color before the transition
• toColor : final color after the transition
• options (optional) : an object that can set the following:
  • callback : function to be called once the animation finishes
  • direction : clockwise (1) or counterclockwise (-1)
  • duration : time (in ms) to complete the animation
  • space : 'HSL', 'HUSL', or 'RGB'

an animation object with pause and resume methods is returned, which can be used like this:

// starts the animation
var transition = sweep(target, properties, fromColor, toColor[, options]);

// stops the animation
transition.pause();

// resumes the animation
transition.pause();

Examples

//click

var ex1 = document.querySelector('#ex1');
ex1.addEventListener('click', function() {
  sweep(ex1, 'backgroundColor', '#a8f', '#a8f', {direction: -1, duration: 2000});
}, false);

//hover

var ex2 = document.querySelector('#ex2'), transition;

ex2.addEventListener('mouseenter', function() {
  if (transition) transition.pause();
  transition = sweep(ex2, 'backgroundColor', getStyle(ex2, 'background-color'), '#0fa');
}, false);

ex2.addEventListener('mouseleave', function() {
  if (transition) transition.pause();
  transition = sweep(ex2, 'backgroundColor', getStyle(ex2, 'background-color'), '#a8f');
}, false);

Check it out on GitHub