A vanilla virtual joystick for touch capable interfaces

Table Of Contents

• Install
• Demo
• Usage
• Options
  • options.zone defaults to 'body'
  • options.color defaults to 'white'
  • options.size defaults to 100
  • options.threshold defaults to 0.1
  • options.fadeTime defaults to 250
  • options.multitouch defaults to false
  • options.maxNumberOfNipples defaults to 1
  • options.dataOnly defaults to false
  • options.position defaults to {top: 0, left: 0}
  • options.mode defaults to 'dynamic'.
    • 'dynamic'
    • 'semi'
    • 'static'
  • options.restOpacity defaults to 0.5
  • options.catchDistance defaults to 200
• API
  • NippleJS instance (manager)
    • manager.on(type, handler)
    • manager.off([type, handler])
    • manager.get(identifier)
    • manager.destroy()
    • manager.ids
    • manager.id
  • nipple instance (joystick)
  • joystick.on, joystick.off
  • joystick.el
  • joystick.show([cb])
  • joystick.hide([cb])
  • joystick.add()
  • joystick.remove()
  • joystick.destroy()
  • joystick.identifier
  • joystick.trigger(type [, data])
  • joystick.position
  • joystick.frontPosition
  • joystick.ui
• Events
  • manager only
    • added
    • removed
  • manager and joysticks
    • start
    • end
    • move
    • dir
    • plain
    • shown
    • hidden
    • destroyed
    • pressure
• Contributing
  • Commits
  • Style
  • Workflow
  • Build

Install

npm install nipplejs --save

// OR

bower install nipplejs --save

---

Demo

Check out the demo here.

---

Usage

Import it the way you want into your project :

// CommonJS
var manager = require('nipplejs').create(options);

// AMD
define(['nipplejs'], function (nipplejs) {
    var manager = nipplejs.create(options);
});

// Global
<script src="./dist/nipplejs.min.js"></script>
<script>
    var manager = nipplejs.create(options);
</script>

⚠️ NB ⚠️ Your joystick's container has to have its CSS position property set, either absolute, relative, static, ....

---

Options

You can configure your joystick in different ways :

var options = {
    zone: Element,                  // active zone
    color: String,
    size: Integer,
    threshold: Float,               // before triggering a directional event
    fadeTime: Integer,              // transition time
    multitouch: Boolean,
    maxNumberOfNipples: Number,     // when multitouch, what is too many?
    dataOnly: Boolean,              // no dom element whatsoever
    position: Object,               // preset position for 'static' mode
    mode: String,                   // 'dynamic', 'static' or 'semi'
    restOpacity: Number,            // opacity when not 'dynamic' and rested
    catchDistance: Number           // distance to recycle previous joystick in
                                    // 'semi' mode
};

All options are optional 😎.

options.zone defaults to 'body'

The dom element in which all your joysticks will be injected.

<div id="zone_joystick"></div>

<script type="text/javascript" src="./nipplejs.min.js"></script>
<script type="text/javascript">
    var options = {
        zone: document.getElementById('zone_joystick');
    };
    var manager = nipplejs.create(options);
</script>

This zone also serve as the mouse/touch events handler.

It represents the zone where all your joysticks will be active.

options.color defaults to 'white'

The background color of your joystick's elements.

Can be any valid CSS color.

options.size defaults to 100

The size in pixel of the outer circle.

The inner circle is 50% of this size.

options.threshold defaults to 0.1

This is the strength needed to trigger a directional event.

Basically, the center is 0 and the outer is 1.

You need to at least go to 0.1 to trigger a directional event.

options.fadeTime defaults to 250

The time it takes for joystick to fade-out and fade-in when activated or de-activated.

options.multitouch defaults to false

Enable the multitouch capabilities.

If, for reasons, you need to have multiple nipples into the same zone.

Otherwise it will only get one, and all new touches won't do a thing.

Please note that multitouch is off when in static or semi modes.

options.maxNumberOfNipples defaults to 1

If you need to, you can also control the maximum number of instance that could be created.

Obviously in a multitouch configuration.

options.dataOnly defaults to false

The library won't draw anything in the DOM and will only trigger events with data.

options.position defaults to {top: 0, left: 0}

An object that will determine the position of a static mode.

You can pass any of the four top, right, bottom and left.

They will be applied as any css property.

Ex :

• {top: '50px', left: '50px'}
• {left: '10%', bottom: '10%'}

options.mode defaults to 'dynamic'.

Three modes are possible :

'dynamic'

• a new joystick is created at each new touch.
• the joystick gets destroyed when released.
• can be multitouch.

'semi'

• new joystick is created at each new touch farther than options.catchDistance of any previously created joystick.
• the joystick is faded-out when released but not destroyed.
• when touch is made inside the options.catchDistance a new direction is triggered immediately.
• when touch is made oustide the options.catchDistance the previous joystick is destroyed and a new one is created.
• cannot be multitouch.

'static'

• a joystick is positionned immediately at options.position.
• one joystick per zone.
• each new touch triggers a new direction.
• cannot be multitouch.

options.restOpacity defaults to 0.5

The opacity to apply when the joystick is in a rest position.

options.catchDistance defaults to 200

This is only useful in the semi mode, and determine at which distance we recycle the previous joystick.

At 200 (px), if you press the zone into a rayon of 200px around the previously displayed joystick, it will act as a static one.

---

API

NippleJS instance (manager)

Your manager has the following signature :

{
    on: Function,                       // handle internal event
    off: Function,                      // un-handle internal event
    get: Function,                      // get a specific joystick
    destroy: Function,                  // destroy everything
    ids: Array                          // array of assigned ids
    id: Number                          // id of the manager
    options: {
        zone: Element,                  // reactive zone
        multitouch: Boolean,
        maxNumberOfNipples: Number,
        mode: String,
        position: Object,
        catchDistance: Number,
        size: Number,
        threshold: Number,
        color: String,
        fadeTime: Number,
        dataOnly: Boolean,
        restOpacity: Number
    }
}

manager.on(type, handler)

If you whish to listen to internal events like :

manager.on('event#1 event#2', function (evt, data) {
    // Do something.
});

Note that you can listen to multiple events at once by separating them either with a space or a comma (or both, I don't care).

manager.off([type, handler])

To remove an event handler :

manager.off('event', handler);

If you call off without arguments, all handlers will be removed.

If you don't specify the handler but just a type, all handlers for that type will be removed.

manager.get(identifier)

An helper to get an instance via its identifier.

// Will return the nipple instanciated by the touch identified by 0
manager.get(0);

manager.destroy()

Gently remove all nipples from the DOM and unbind all events.

manager.destroy();

manager.ids

The array of nipples' ids under this manager.

manager.id

The incremented id of this manager.

nipple instance (joystick)

Each joystick has the following signature :

{
    on: Function,
    off: Function,
    el: Element,
    show: Function,         // fade-in
    hide: Function,         // fade-out
    add: Function,          // inject into dom
    remove: Function,       // remove from dom
    destroy: Function,
    identifier: Number,
    trigger: Function,
    position: {             // position of the center
        x: Number,
        y: Number
    },
    frontPosition: {        // position of the front part
        x: Number,
        y: Number
    },
    ui: {
        el: Element,
        front: Element,
        back: Element
    },
    options: {
        color: String,
        size: Number,
        threshold: Number,
        fadeTime: Number
    }
}

joystick.on, joystick.off

The same as the manager.

joystick.el

Dom element in which the joystick gets created.

<div class="nipple">
    <div class="front"></div>
    <div class="back"></div>
</div>

joystick.show([cb])

Will show the joystick at the last known place.

You can pass a callback that will be executed at the end of the fade-in animation.

joystick.hide([cb])

Will fade-out the joystick.

You can pass a callback that will be executed at the end of the fade-out animation.

joystick.add()

Add the joystick's element to the dom.

joystick.remove()

Remove the joystick's element from the dom.

joystick.destroy()

Gently remove this nipple from the DOM and unbind all related events.

joystick.identifier

Returns the unique identifier of the joystick.

Tied to its touch's identifier.

joystick.trigger(type [, data])

Trigger an internal event from the joystick.

The same as on you can trigger multiple events at the same time.

joystick.position

The absolute position of the center of the joystick.

joystick.frontPosition

The absolute position of the back part of the joystick's ui.

joystick.ui

The object that store its ui elements

{
    el: <div class="nipple"></div>
    back: <div class="back"></div>
    front: <div class="front"></div>
}

---

Events

You can listen events both on the manager and all the joysticks.

But some of them are specific to its instance.

If you need to listen to each joystick, for example, you can :

manager.on('added', function (evt, nipple) {
    nipple.on('start move end dir plain', function (evt) {
        // DO EVERYTHING
    });
}).on('removed', function (evt, nipple) {
    nipple.off('start move end dir plain');
});

manager only

added

A joystick just got added.

Will pass the instance alongside the event.

removed

A joystick just got removed.

Fired at the end of the fade-out animation.

Will pass the instance alongside the event.

Won't be trigger in a dataOnly configuration.

manager and joysticks

Other events are available on both the manager and joysticks.

When listening on the manager, you can also target a joystick in particular by prefixing the event with its identifier, 0:start for example.

Else you'll get all events from all the joysticks.

start

A joystick is activated. (the user pressed on the active zone)

Will pass the instance alongside the event.

end

A joystick is de-activated. (the user released the active zone)

Will pass the instance alongside the event.

move

A joystick is moved.

Comes with data :

{
    identifier: 0,              // the identifier of the touch/mouse that triggered it
    position: {                 // absolute position of the center in pixels
        x: 125,
        y: 95
    },
    force: 0.2,                 // strength in %
    distance: 25.4,             // distance from center in pixels
    pressure: 0.1,              // the pressure applied by the touch
    angle: {
        radian: 1.5707963268,   // angle in radian
        degree: 90
    },
    instance: Nipple            // the nipple instance that triggered the event
}

dir

When a direction is reached after the threshold.

Direction are split with a 45° angle.

//     \  UP /
//      \   /
// LEFT       RIGHT
//      /   \
//     /DOWN \

You can also listen to specific direction like :

• dir:up
• dir:down
• dir:right
• dir:left

In this configuration only one direction is triggered at a time.

plain

When a plain direction is reached after the threshold.

Plain directions are split with a 90° angle.

//       UP               |
//     ------        LEFT | RIGHT
//      DOWN              |

You can also listen to specific plain direction like :

• plain:up
• plain:down
• plain:right
• plain:left

In this configuration two directions can be triggered at a time, because the user could be both up and left for example.

shown

Is triggered at the end of the fade-in animation.

Will pass the instance alongside the event.

Won't be trigger in a dataOnly configuration.

hidden

Is triggered at the end of the fade-out animation.

Will pass the instance alongside the event.

Won't be trigger in a dataOnly configuration.

destroyed

Is triggered at the end of destroy.

Will pass the instance alongside the event.

pressure

MBP's Force Touch, iOS's 3D Touch, Microsoft's pressure or MDN's force

Is triggered when the pressure on the joystick is changed.

The value, between 0 and 1, is sent back alongside the event.

---

Contributing

Your help is more than welcome, I would be very honored to have you on my side.

Here are some very basic guidelines.

Commits

Please follow these guidelines so your commits will be taken by the self-generated changelog.

Style

There are both JSCS and ESLint in the project.

To test your code against them simply run npm run prebuild.

We follow a 4 spaces rule around here.

Workflow

You can use the available scripts if needed.

• npm run watch will run the build each time a change is detected.
• npm run formatAndLint will test the formatting and the linting of your code.
• npm start will run a static server that will serve the test/ folder on localhost:8080.
• npm test will test using CasperJS, you have to run npm start in another window to have a local server available to CasperJS.

Build

Once you're satisfied with your changes, you can also include a build.

1. npm run build to generate built files.
2. commit your build with the message chore: new build.
3. npm version patch|minor|major depending on your change. Changelog will be generated and bower's version synced and everything is automatically committed (not pushed though).