README

tween.js

JavaScript tweening engine for easy animations, incorporating optimised Robert Penner's equations.

var box = document.createElement('div');
box.style.setProperty('background-color', '#008800');
box.style.setProperty('width', '100px');
box.style.setProperty('height', '100px');
document.body.appendChild(box);

// Setup the animation loop.
function animate(time) {
    requestAnimationFrame(animate);
    TWEEN.update(time);
}
requestAnimationFrame(animate);

var coords = { x: 0, y: 0 }; // Start at (0, 0)
var tween = new TWEEN.Tween(coords) // Create a new tween that modifies 'coords'.
        .to({ x: 300, y: 200 }, 1000) // Move to (300, 200) in 1 second.
        .easing(TWEEN.Easing.Quadratic.Out) // Use an easing function to make the animation smooth.
        .onUpdate(function() { // Called after tween.js updates 'coords'.
            // Move 'box' to the position described by 'coords' with a CSS translation.
            box.style.setProperty('transform', 'translate(' + coords.x + 'px, ' + coords.y + 'px)');
        })
        .start(); // Start the tween immediately.

Test it with CodePen

Installation

Download the library and include it in your code:

<script src="js/Tween.js"></script>

You can also reference a CDN-hosted version in your code, thanks to cdnjs. For example:

<script src="https://cdnjs.cloudflare.com/ajax/libs/tween.js/16.3.5/Tween.min.js"></script>

See tween.js for more versions.

More advanced users might want to...

Use `npm`

npm install @tweenjs/tween.js

Then include the Tween.js module with the standard node.js require:

var TWEEN = require('@tweenjs/tween.js');

And you can use Tween.js as in all other examples--for example:

var t = new TWEEN.Tween( /* etc */ );
t.start();

You will need to use a tool such as browserify to convert code using this style into something that can be run in the browser (browsers don't know about require).

Use `bower`

bower install @tweenjs/tweenjs --save

or install an specific tag. They are git tags, and you can run git tag in the command line for a list if you have cloned the repository locally, or you can also check out the list in the tween.js tags page. For example, to install v16.3.0:

bower install @tweenjs/tweenjs#v16.3.0

Then reference the library source:

<script src="bower_components/@tweenjs/tweenjs/src/Tween.js"></script>

Features

Does one thing and one thing only: tween properties
Doesn't take care of CSS units (e.g. appending px)
Doesn't interpolate colours
Easing functions are reusable outside of Tween
Can also use custom easing functions

Documentation

User guide
Contributor guide
Tutorial using tween.js with three.js
Also: libtween, a port of tween.js to C by jsm174
Also: es6-tween, a port of tween.js to ES6/Harmony by dalisoft
Understanding tween.js

Examples

	Custom functions (source)		Stop all chained tweens (source)
	Yoyo (source)		Relative values (source)
	Repeat (source)		Dynamic to (source)
	Array interpolation (source)		Video and time (source)
	Simplest possible example (source)		Graphs (source)
	Black and red (source)		Bars (source)
	hello world (source)

Tests

You need to install npm first--this comes with node.js, so install that one first. Then, cd to tween.js's directory and run:

npm install

if running the tests for the first time, to install additional dependencies for running tests, and then run

npm test

every time you want to run the tests.

If you want to add any feature or change existing features, you must run the tests to make sure you didn't break anything else. If you send a pull request (PR) to add something new and it doesn't have tests, or the tests don't pass, the PR won't be accepted. See contributing for more information.