A virtual joystick for touch capable interfaces

Install

npm install nipplejs --save

// OR

bower install nipplejs --save

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Demo

Check out the demo here.

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Usage

Import it the way you want into your project :

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

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

// Global
<script type="text/javascript" src="./dist/nipplejs.min.js"></script>
<script type="text/javascript">
    var joystick = nipplejs.create(options);
</script>

---

Options

You can configure your joystick in different ways :

var options = {
    zone: Element,
    color: String,
    size: Integer,
    threshold: Float,
    fadeTime: Integer
};

All options are optional.

[zone] defaults to 'body'

The dom element in which your joystick 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 joystick = nipplejs.create(options);
</script>

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

It represents the zone where your joystick will be active.

[color] defaults to 'white'

The background color of your joystick's elements.

Can be any valid CSS color.

[size] defaults to 100

The size in pixel of the outer circle.

The inner circle is 50% of this size.

[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.

[fadeTime] defaults to 250

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

---

API

Your nipplejs instance will come back as :

{
    el: Element,
    on: Function,
    off: Function,
    options: Object,
    ui: Object
}

el

Dom element in which the joystick gets created.

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

on

If you whish to listen to internal events like :

joystick.on('event', function (evt, data) {
    // Do something.
});

off

To remove an event handler :

joystick.off('event', handler);

options

Simply the options you passed at its creation.

ui

The object that store its ui elements

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

---

Events

start

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

end

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

move

The joystick is moved. Comes with data :

{
    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
    angle: {
        radian: 1.5707963268, // angle in radian
        degree: 90
    }
}

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.

//       U|P
//LEFT____|___ RIGHT
//        |
//      DO|WN

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.