Simple, lightweight Parallax Engine that reacts to the orientation of a smart device. Where no gyroscope or motion detection hardware is available, the position of the cursor is used instead.
This version is a fork by Christophe Rosset (@topheman), from the original Parallax.js by Matthew Wagerfield. It adds headtracking support to the original library. See Headtracking Support section for more infos.
Check out this demo to see it in action !
Simply create a list of elements giving each item that you want to move within
your parallax scene a class of layer and a data-depth attribute specifying
its depth within the scene. A depth of 0 will cause the layer to remain
stationary, and a depth of 1 will cause the layer to move by the total
effect of the calculated motion. Values inbetween 0 and 1 will cause the
layer to move by an amount relative to the supplied ratio.
<ul id="scene">
<li class="layer" data-depth="0.00"><img src="layer6.png"></li>
<li class="layer" data-depth="0.20"><img src="layer5.png"></li>
<li class="layer" data-depth="0.40"><img src="layer4.png"></li>
<li class="layer" data-depth="0.60"><img src="layer3.png"></li>
<li class="layer" data-depth="0.80"><img src="layer2.png"></li>
<li class="layer" data-depth="1.00"><img src="layer1.png"></li>
</ul>To kickoff a Parallax scene, simply select your parent DOM Element and pass it to the Parallax constructor.
var scene = document.getElementById('scene');
var parallax = new Parallax(scene);There are a number of behaviours that you can setup for any given Parallax instance. These behaviours can either be specified in the markup via data attributes or in JavaScript via the constructor and API.
| Behavior | Values | Description |
|---|---|---|
calibrate-x |
true or false |
Specifies whether or not to cache & calculate the motion relative to the initial x axis value on initialisation. |
calibrate-y |
true or false |
Specifies whether or not to cache & calculate the motion relative to the initial y axis value on initialisation. |
invert-x |
true or false |
true moves layers in opposition to the device motion, false slides them away. |
invert-y |
true or false |
true moves layers in opposition to the device motion, false slides them away. |
limit-x |
number or false |
A numeric value limits the total range of motion in x, false allows layers to move with complete freedom. |
limit-y |
number or false |
A numeric value limits the total range of motion in y, false allows layers to move with complete freedom. |
scalar-x |
number |
Multiplies the input motion by this value, increasing or decreasing the sensitivity of the layer motion. |
scalar-y |
number |
Multiplies the input motion by this value, increasing or decreasing the sensitivity of the layer motion. |
friction-x |
number 0 - 1 |
The amount of friction the layers experience. This essentially adds some easing to the layer motion. |
friction-y |
number 0 - 1 |
The amount of friction the layers experience. This essentially adds some easing to the layer motion. |
In addition to the behaviours described above, there are two methods enable()
and disable() that activate and deactivate the Parallax instance respectively.
<ul id="scene"
data-calibrate-x="false"
data-calibrate-y="true"
data-invert-x="false"
data-invert-y="true"
data-limit-x="false"
data-limit-y="10"
data-scalar-x="2"
data-scalar-y="8"
data-friction-x="0.2"
data-friction-y="0.8">
<li class="layer" data-depth="0.00"><img src="graphics/layer6.png"></li>
<li class="layer" data-depth="0.20"><img src="graphics/layer5.png"></li>
<li class="layer" data-depth="0.40"><img src="graphics/layer4.png"></li>
<li class="layer" data-depth="0.60"><img src="graphics/layer3.png"></li>
<li class="layer" data-depth="0.80"><img src="graphics/layer2.png"></li>
<li class="layer" data-depth="1.00"><img src="graphics/layer1.png"></li>
</ul>var scene = document.getElementById('scene');
var parallax = new Parallax(scene, {
calibrateX: false,
calibrateY: true,
invertX: false,
invertY: true,
limitX: false,
limitY: 10,
scalarX: 2,
scalarY: 8,
frictionX: 0.2,
frictionY: 0.8
});var scene = document.getElementById('scene');
var parallax = new Parallax(scene);
parallax.enable();
parallax.disable();
parallax.calibrate(false, true);
parallax.invert(false, true);
parallax.limit(false, 10);
parallax.scalar(2, 8);
parallax.friction(0.2, 0.8);If you're using jQuery or Zepto and would prefer to use Parallax.js as a plugin, you're in luck!
$('#scene').parallax();$('#scene').parallax({
calibrateX: false,
calibrateY: true,
invertX: false,
invertY: true,
limitX: false,
limitY: 10,
scalarX: 2,
scalarY: 8,
frictionX: 0.2,
frictionY: 0.8
});var $scene = $('#scene').parallax();
$scene.parallax('enable');
$scene.parallax('disable');
$scene.parallax('calibrate', false, true);
$scene.parallax('invert', false, true);
$scene.parallax('limit', false, 10);
$scene.parallax('scalar', 2, 8);
$scene.parallax('friction', 0.2, 0.8);Use Parallax.js just as you would. But rather than devicemotion, use headtracking with your webcam. Thanks to Audun Mathias Øygard for his headtrackr.js library.
Don't forget to insert the headtrackr.js or headtrackr.min.js script in your page or specify it in the options in headtrackr-script-location (for lazy load).
Some getUserMedia feature detection is done, if you're not on firefox or chrome (which implement the feature at the moment), the headtrackr script won't even be downloaded and you'll have a message telling you that headtracking won't work and falls back to normal behaviour.
You can test the headtracking version of the simple demo here :
See also the real demo.
var scene = document.getElementById('scene');
var parallax = new Parallax(scene, {
// … set any of the usual parallax behaviours, then set the headtrackr ones
headtrackr:true,
headtrackrPreferDeviceMotion:false,//if on a device that supports both getUserMedia and accelerometer, false -> will use headtrackr, true -> will use DeviceMotion (true by default to keep with parallax.js)
scalarX: 15.0,
scalarY: 15.0,
// headtrackrDisplayVideo:true, //no need if you set headtrackrDebugView at true
headtrackrDebugView: true,
invertX:false,
invertY:false,
headtrackrScriptLocation: "../deploy/headtrackr.min.js",
headtrackrOnBeforeCameraAccess: function(){
console.log('Trying to access to your webcam - this is where you could display a "please allow your webcam" message for example');
},
headtrackrOnCameraFound: function(){
var headtrackerMessageDiv = document.getElementById('headtrackerMessageDiv');
//at this time, you're sure the user clicked on "allow" and the webcam is rolling (you can override the inline styles of the headtrackr div message)
headtrackerMessageDiv.style.top = "20%";
},
headtrackrNoGetUserMediaCallback: function(){
console.log('Write your own message function like a modal or anything better than the ugly message I made up … ;-)');
}
});var scene = document.getElementById('scene');
var parallax = new Parallax(scene);
parallax.headtrackrScalar(2, 8);$('#scene').parallax({
// … set any of the usual parallax behaviours, then set the headtrackr ones
headtrackr:true,
headtrackrPreferDeviceMotion:false,//if on a device that supports both getUserMedia and accelerometer, false -> will use headtrackr, true -> will use DeviceMotion (true by default to keep with parallax.js)
scalarX: 15.0,
scalarY: 15.0,
// headtrackrDisplayVideo:true, //no need if you set headtrackrDebugView at true
headtrackrDebugView: true,
invertX:false,
invertY:false,
headtrackrScriptLocation: "../deploy/headtrackr.min.js",
headtrackrOnBeforeCameraAccess: function(){
console.log('Trying to access to your webcam - this is where you could display a "please allow your webcam" message for example');
},
headtrackrOnCameraFound: function(){
var headtrackerMessageDiv = document.getElementById('headtrackerMessageDiv');
//at this time, you're sure the user clicked on "allow" and the webcam is rolling (you can override the inline styles of the headtrackr div message)
headtrackerMessageDiv.style.top = "20%";
},
headtrackrNoGetUserMediaCallback: function(){
console.log('Write your own message function like a modal or anything better than the ugly message I made up … ;-)');
}
});var $scene = $('#scene').parallax();
$scene.parallax('headtrackrScalar', 2, 8);Keep in mind that to activate headtracking you only have to put headtrackr option to true, the other parameters are optional (except headtrackr-script-location, unless you already have included the headtrackr.js script).
| Behavior | Values | Description |
|---|---|---|
headtrackr |
true or false |
Activates headtracking in parallax (you will be asked to allow the access to your webcam) - it disables devicemotion events and uses mouse if headtracking fails |
headtrackr-display-video |
true or false |
Specifies whether or not to display the webcam video stream (false by default) |
headtrackr-scalar-x |
number |
Multiplies the input motion given by headtrackr by this value (will be affected by scalar-x) |
headtrackr-scalar-y |
number |
Multiplies the input motion given by headtrackr by this value (will be affected by scalar-y) |
headtrackr-debug-view |
true or false |
Specifies whether or not to display the webcam video stream, with a box over your head (great for debugging) (false by default) |
headtrackr-script-location |
string |
Location of the headtrackr.js or headtrackr.min.js script (lazy load for feature detection) |
headtrackr-prefer-device-motion |
true or false |
If both accelerometer and headtracking are supported (like on tablets with chrome that support getUserMedia), choose which one use, true by default |
If you are writing a native iOS application and would like to use parallax.js
within a UIWebView, you will need to do a little bit of work to get it running.
UIWebView no longer automatically receives the deviceorientation event, so
your native application must intercept the events from the gyroscope and reroute
them to the UIWebView:
- Include the CoreMotion framework
#import <CoreMotion/CoreMotion.h>and create a reference to the UIWebView@property(nonatomic, strong) IBOutlet UIWebView *parallaxWebView; - Add a property to the app delegate (or controller that will own the UIWebView)
@property(nonatomic, strong) CMMotionManager *motionManager; - Finally, make the following calls:
self.motionManager = [[CMMotionManager alloc] init];
if (self.motionManager.isGyroAvailable && !self.motionManager.isGyroActive) {
[self.motionManager setGyroUpdateInterval:0.5f]; // Set the event update frequency (in seconds)
[self.motionManager startGyroUpdatesToQueue:NSOperationQueue.mainQueue
withHandler:^(CMGyroData *gyroData, NSError *error) {
NSString *js = [NSString stringWithFormat:@"parallax.onDeviceOrientation({beta:%f, gamma:%f})", gyroData.rotationRate.x, gyroData.rotationRate.y];
[self.parallaxWebView stringByEvaluatingJavaScriptFromString:js];
}];
}cd build
npm install
node build.js
- Matthew Wagerfield: @mwagerfield
- Christophe Rosset: @topheman
Licensed under MIT. Enjoy.