0.3.9 • Public • Published

Logo famous-flex

Animatable layouts, FlexScrollView & widgets for famo.us.


Above anything, famous-flex is a concept in which renderables are seperated from how they are layed-out. This makes it possible to change layouts on the fly and animate the renderables from one layout to another. For instance, you can layout a collection of renderables using a CollectionLayout, and change that into a ListLayout. When using flow-mode the renderables will smoothly transition from the old state to the new state using physics, particles and springs.

2016 Update!

Many people have asked me what the future of famous-flex holds, and I would like to shed some light on this.. I've been working on a big update to famous-flex for some time now. Initially it was to be based on the mixed-mode release of famo.us, but this doesn't seem future proof at the moment. It will therefore be based on (or rather run on top of) famous v3 and Samsara.js. The new library shall contain an extensive set of out-of-the-box controls such as a switch, slider, progress-bar, label, tab-bar, scrollview, etc... All controls will be highly customizable and highly animatable. The idea here is to have a complete and solid set of building blocks for quickly building web/apps.

A second goal will be to use famous-flex as an output target for NativeScript apps. Using NativeScript it is possible to write native apps (iOS/Android) using the power of javascript. How awesome would it be to be able to run these apps in the browser as well. I have clear use cases for this and my customers would benefit from this. I want the ability to be able to write a mobile app and website using a shared code-base, and have native performance characteristics for the mobile apps.

All the best, IjzerenHein


Getting started

Core concepts

Views / widgets




Install using bower or npm:

bower install famous-flex

npm install famous-flex


LayoutController is a view that lays out renderables based on:

  • a layout-function
  • a data-source containing renderables
  • optional layout-options

Example of laying out renderables using a CollectionLayout:

var LayoutController = require('famous-flex/LayoutController');
var CollectionLayout = require('famous-flex/layouts/CollectionLayout'); // import standard layout
// create collection-layout
var layoutController = new LayoutController({
    layout: CollectionLayout,
    layoutOptions: {
        itemSize: [100, 100],
        gutter: [20, 20],
        justify: true
    flow: true,    // smoothly animates renderables when changing the layout
    direction: 1,  // 0 = X, 1 = Y, undefined = use default from selected layout-function
    dataSource: [
        new Surface({content: 'surface1'}),
        new Surface({content: 'surface2'}),
        new Surface({content: 'surface3'})
this.add(layoutController); // add layout-controller to the render-tree

When the flow option is enabled, renderables are animated smoothly between layout states.

Layout function

A layout is represented as a Function, which takes a context argument and an optional options argument. The purpose of the function is to lay-out the renderables in the data-source by calling context.set() on a renderable. The renderables can be enumerated by calling context.next(), context.prev() or by using the id of the renderable.

Famous-flex comes shipped with various standard layouts, but it is also very easy to create your own layout-functions. View LayoutContext for more details on creating your own layout-functions.

 * @param {LayoutContext} context Context used for enumerating renderables and setting the layout
 * @param {Object} [options] additional layout-options that are passed to the function
function LayoutFunction(context, options) {
    // simple layout-function that lays out renderables from top to bottom
    var node = context.next();
    var y = 0;
    while (node) {
        context.set(node, {
            size: [context.size[0], 100],
            translate: [0, y, 0]
        y += 100;
        node = context.next();

For optimal performance, the layout function is only executed when:

  • A resize occurs
  • An option is changed on the layout-controller
  • When the content is scrolled


The data-source contains the renderables that are to be layed-out. It can be one of three things:

  • An Array
  • A LinkedListViewSequence
  • A VirtualViewSequence
  • An Object with key/value pairs

In case of an Array or a ViewSequence, use context.next() in your layout-function to enumerate all the renderables in the data-source:

var layoutController = new LayoutController({
    layout: function (context, options) {
        var y = 0;
        var node = context.next();
        while (node) {
            context.set(node, {
                size: [context.size[0], 100],
                translate: [0, y, 0]
            y += 100;
            node = context.next();
    dataSource: [
        new Surface({content: 'surface1'}),
        new Surface({content: 'surface2'}),
        new Surface({content: 'surface3'})

Sometimes it is easier to identify renderables by an id, rather than a sequence. In that case use context.get() or directly pass the data-source id to the context.set() function:

var layoutController = new LayoutController({
    layout: function (context, options) {
        context.set('one', {
            size: [100, 100],
            translate: [0, 0, 0]
        context.set('two', {
            size: [100, 100],
            translate: [100, 0, 0]
        context.set('three', {
            size: [100, 100],
            translate: [200, 0, 0]
    dataSource: {
        'one': new Surface({content: 'one'}),
        'two': new Surface({content: 'two'}),
        'three': new Surface({content: 'three'})

Layout literals

Layout literals are objects which describe layouts through a definition rather than a function. The following example describes the use of a layout literal using dock semantics (see LayoutDockHelper):

var layoutController = new LayoutController({
    layout: {dock: [
        ['top', 'header', 50],
        ['bottom', 'footer', 50],
        ['fill', 'content']
    dataSource: {
        header: new Surface({content: 'Header'}),
        footer: new Surface({content: 'Footer'}),
        content: new Surface({content: 'Content'})

Layout literals are implemented through LayoutHelpers. To create your own layout literals, perform the following steps:

  • Create a LayoutHelper (see LayoutDockHelper for an example).
  • Implement the parse function on the LayoutHelper.
  • Register the helper using LayoutUtility.registerHelper.

Layout helpers

Layout helpers are special classes that simplify writing layout functions.

Helper Literal Description
LayoutDockHelper dock Layout renderables using docking semantics.

Standard layouts

Layout DataSource Scrollable Description
ProportionalLayout LinkedListViewSequence / Array No Lays out renderables sequentially and sizes them proportionally.
HeaderFooterLayout Id-based No Layout containing a top-header, bottom- footer and content.
NavBarLayout Id-based No Layout containing one or more left and right items and a title.
TabBarLayout Id-based No Tab-bar layout.
Scrollable layouts:
ListLayout LinkedListViewSequence / Array Yes List layout with margins, spacing and optionally sticky headers.
CollectionLayout LinkedListViewSequence / Array Yes Lays out renderables in a grid with a specific width & height.
WheelLayout LinkedListViewSequence / Array Yes Lays out renderables in a wheel (slot-machine) formation.
CoverLayout LinkedListViewSequence / Array Yes Lays out renderables in a wheel (slot-machine) formation.


Class Description
LayoutController Lays out renderables and optionally animates between layout states.
AnimationController Animating between famo.us views in awesome ways.
ScrollController Scrollable LayoutController (base class for FlexScrollView).
FlexScrollView Flexible scroll-view with pull-to-refresh, margins & spacing and more good stuff.
DatePicker Date/time picker wheel.
TabBar TabBar widget.
TabBarController TabBarController widget.
LayoutContext Context used for writing layout-functions.
LayoutUtility Utility class containing helper functions.
VirtualViewSequence Infinite view-sequence which uses a factory delegate to create renderables.
LinkedListViewSequence Linked-list based View-sequence which resolves various issues with the stock famo.us ViewSequence.


If you like this project and want to support it, show some love and give it a star. Any donations are also very welcome and appreciated. To donate click here.


© 2014 - 2016 Hein Rutjes

Package Sidebar


npm i famous-flex

Weekly Downloads






Last publish


  • ijzerenhein