Detetar orientação do dispositivo

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

Increasingly, web-enabled devices are capable of determining their orientation; that is, they can report data indicating changes to their orientation with relation to the pull of gravity. In particular, hand-held devices such as mobile phones can use this information to automatically rotate the display to remain upright, presenting a wide-screen view of the web content when the device is rotated so that its width is greater than its height.

There are two JavaScript events that handle orientation information. The first one is the DeviceOrientationEvent, which is sent when the accelerometer detects a change to the orientation of the device. By receiving and processing the data reported by these orientation events, it's possible to interactively respond to rotation and elevation changes caused by the user moving the device.

The second event is the DeviceMotionEvent, which is sent when a change in acceleration was added. It is different from the DeviceOrientationEvent because it is listening for changes in acceleration as opposed to orientation. Sensors that are commonly capable of detecting DeviceMotionEvent include sensors in laptops to protect moving storage devices. DeviceOrientationEvent is more commonly found in mobile devices.

Processar eventos de orientação

All you need to do in order to begin receiving orientation change is to listen to the deviceorientation event:

Nota: gyronorm.js is a polyfill for normalizing the accelerometer and gyroscope data on mobile devices. This is useful for overcoming some of the differences in device support for device orientation.

window.addEventListener("deviceorientation", handleOrientation, true);

After registering your event listener (in this case, a JavaScript function called handleOrientation()), your listener function periodically gets called with updated orientation data.

The orientation event contains four values:

The event handler function can look something like this:

function handleOrientation(event) {
  var absolute = event.absolute;
  var alpha    = event.alpha;
  var beta     = event.beta;
  var gamma    = event.gamma;

  // Do stuff with the new orientation data
}

Valores de orientação explicados

The value reported for each axis indicates the amount of rotation around a given axis in reference to a standard coordinate frame. These are described in greater detail in the Orientation and motion data explained article which is summarized below.

  • The DeviceOrientationEvent.alpha value represents the motion of the device around the z axis, represented in degrees with values ranging from 0 to 360.
  • The DeviceOrientationEvent.beta value represents the motion of the device around the x axis, represented in degrees with values ranging from -180 to 180. This represents a front to back motion of the device.
  • The DeviceOrientationEvent.gamma value represents the motion of the device around the y axis, represented in degrees with values ranging from -90 to 90. This represents a left to right motion of the device.

Exemplo de orientação

This example will work on any browser supporting the deviceorientation event and running on a device able to detect its orientation.

So let's imagine a ball in a garden:

<div class="garden">
  <div class="ball"></div>
</div>

<pre class="output"></pre>

This garden is 200 pixel wide (Yes, it's a tiny one), and the ball is in the center:

.garden {
  position: relative;
  width : 200px;
  height: 200px;
  border: 5px solid #CCC;
  border-radius: 10px;
}

.ball {
  position: absolute;
  top   : 90px;
  left  : 90px;
  width : 20px;
  height: 20px;
  background: green;
  border-radius: 100%;
}

Now, if we move our device, the ball will move accordingly:

var ball   = document.querySelector('.ball');
var garden = document.querySelector('.garden');
var output = document.querySelector('.output');

var maxX = garden.clientWidth  - ball.clientWidth;
var maxY = garden.clientHeight - ball.clientHeight;

function handleOrientation(event) {
  var x = event.beta;  // In degree in the range [-180,180]
  var y = event.gamma; // In degree in the range [-90,90]

  output.innerHTML  = "beta : " + x + "\n";
  output.innerHTML += "gamma: " + y + "\n";

  // Because we don't want to have the device upside down
  // We constrain the x value to the range [-90,90]
  if (x >  90) { x =  90};
  if (x < -90) { x = -90};

  // To make computation easier we shift the range of 
  // x and y to [0,180]
  x += 90;
  y += 90;

  // 10 is half the size of the ball
  // It center the positioning point to the center of the ball
  ball.style.top  = (maxX*x/180 - 10) + "px";
  ball.style.left = (maxY*y/180 - 10) + "px";
}

window.addEventListener('deviceorientation', handleOrientation);

Click here to open this example in a new window; because deviceorientation doesn't work in a cross-origin <iframe> in all browsers.

 

Aviso: Chrome and Firefox do not handle the angles the same way, so on some axes the direction are reversed.

Processar eventos de movimento

Motion events are handled the same way as the orientation events except that they have their own event's name: devicemotion

window.addEventListener("devicemotion", handleMotion, true);

What's really changed are the information provided within the DeviceMotionEvent object passed as a parameter of the HandleMotion function.

The motion event contains four properties:

Valores de movimento explicados

The DeviceMotionEvent objects provide web developers with information about the speed of changes for the device's position and orientation. The changes are provided along three axis (see Orientation and motion data explained for details).

For acceleration and accelerationIncludingGravity, those axes correspond to the following:

  • x: Represents the axis from West to East
  • y: Represents the axis from South to North
  • z: Represents the axis perpendicular to the ground

For rotationRate, the situation is a bit different; the information corresponds to the following in each case:

  • alpha: Represents a rotation rate along the axis perpendicular to the screen (or keyboard for desktop).
  • beta: Represents a rotation rate along the axis going from left to right of the plane of the screen (or keyboard for desktop).
  • gamma: Represents a rotation rate along the axis going from bottom to top of the plane of the screen (or keyboard for desktop).

Finally, interval represents the interval of time, in milliseconds, at which data are obtain from the device.

Especificações

Especificação Estado Comentário
DeviceOrientation Event Specification Editor's Draft Initial specification.

Compatibilidade de navegador

DeviceMotionEvent

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
DeviceMotionEvent
Experimental
Chrome Full support YesEdge Full support YesFirefox Full support 6IE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 6Opera Android No support NoSafari iOS Full support 4.2Samsung Internet Android Full support Yes
DeviceMotionEvent() constructor
ExperimentalNon-standard
Chrome Full support 59Edge ? Firefox ? IE ? Opera ? Safari ? WebView Android Full support 59Chrome Android Full support 59Firefox Android ? Opera Android No support NoSafari iOS ? Samsung Internet Android ?
acceleration
Experimental
Chrome Full support YesEdge Full support 12Firefox Full support 6IE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 6Opera Android No support NoSafari iOS Full support 4.2Samsung Internet Android Full support Yes
accelerationIncludingGravity
Experimental
Chrome Full support YesEdge Full support 12Firefox Full support 6IE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 6Opera Android No support NoSafari iOS Full support 4.2Samsung Internet Android Full support Yes
interval
Experimental
Chrome Full support YesEdge Full support 12Firefox Full support 6IE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 6Opera Android No support NoSafari iOS Full support 4.2Samsung Internet Android Full support Yes
rotationRate
Experimental
Chrome Full support YesEdge Full support 12Firefox Full support 6IE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 6Opera Android No support NoSafari iOS Full support 4.2Samsung Internet Android Full support Yes

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.

DeviceOrientationEvent

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
DeviceOrientationEvent
Experimental
Chrome Full support 7
Notes
Full support 7
Notes
Notes Before version 50, Chrome provided absolute values instead of relative values for this event. Developers still needing absolute values may use the ondeviceorientationabsolute event.
Edge Full support YesFirefox Full support 6
Notes
Full support 6
Notes
Notes Firefox 3.6, 4, and 5 supported mozOrientation instead of the standard DeviceOrientationEvent interface.
IE ? Opera Full support YesSafari ? WebView Android Full support Yes
Notes
Full support Yes
Notes
Notes Before version 50, Chrome provided absolute values instead of relative values for this event. Developers still needing absolute values may use the ondeviceorientationabsolute event.
Chrome Android Full support Yes
Notes
Full support Yes
Notes
Notes Before version 50, Chrome provided absolute values instead of relative values for this event. Developers still needing absolute values may use the ondeviceorientationabsolute event.
Firefox Android Full support 6
Notes
Full support 6
Notes
Notes Firefox 3.6, 4, and 5 supported mozOrientation instead of the standard DeviceOrientationEvent interface.
Opera Android No support NoSafari iOS Full support 4.2Samsung Internet Android Full support Yes
DeviceOrientationEvent() constructor
ExperimentalNon-standard
Chrome Full support 59Edge ? Firefox ? IE ? Opera ? Safari ? WebView Android Full support 59Chrome Android Full support 59Firefox Android ? Opera Android No support NoSafari iOS ? Samsung Internet Android ?
absolute
Experimental
Chrome Full support 7Edge Full support 12Firefox Full support 6IE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 6Opera Android No support NoSafari iOS Full support 4.2Samsung Internet Android Full support Yes
alpha
Experimental
Chrome Full support 7Edge Full support 12Firefox Full support 6IE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 6Opera Android No support NoSafari iOS Full support 4.2Samsung Internet Android Full support Yes
beta
Experimental
Chrome Full support 7Edge Full support 12Firefox Full support 6IE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 6Opera Android No support NoSafari iOS Full support 4.2Samsung Internet Android Full support Yes
gamma
Experimental
Chrome Full support 7Edge Full support 12Firefox Full support 6IE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 6Opera Android No support NoSafari iOS Full support 4.2Samsung Internet Android Full support Yes

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.
See implementation notes.
See implementation notes.

Consultar também