OpenLayers

Class: DeviceOrientation

ol.DeviceOrientation 


import DeviceOrientation from 'ol/deviceorientation';

The ol.DeviceOrientation class provides access to information from DeviceOrientation events. See the HTML 5 DeviceOrientation Specification for more details.

Many new computers, and especially mobile phones and tablets, provide hardware support for device orientation. Web developers targeting mobile devices will be especially interested in this class.

Device orientation data are relative to a common starting point. For mobile devices, the starting point is to lay your phone face up on a table with the top of the phone pointing north. This represents the zero state. All angles are then relative to this state. For computers, it is the same except the screen is open at 90 degrees.

Device orientation is reported as three angles - alpha, beta, and gamma - relative to the starting position along the three planar axes X, Y and Z. The X axis runs from the left edge to the right edge through the middle of the device. Similarly, the Y axis runs from the bottom to the top of the device through the middle. The Z axis runs from the back to the front through the middle. In the starting position, the X axis points to the right, the Y axis points away from you and the Z axis points straight up from the device lying flat.

The three angles representing the device orientation are relative to the three axes. alpha indicates how much the device has been rotated around the Z axis, which is commonly interpreted as the compass heading (see note below). beta indicates how much the device has been rotated around the X axis, or how much it is tilted from front to back. gamma indicates how much the device has been rotated around the Y axis, or how much it is tilted from left to right.

For most browsers, the alpha value returns the compass heading so if the device points north, it will be 0. With Safari on iOS, the 0 value of alpha is calculated from when device orientation was first requested. ol.DeviceOrientation provides the heading property which normalizes this behavior across all browsers for you.

It is important to note that the HTML 5 DeviceOrientation specification indicates that alpha, beta and gamma are in degrees while the equivalent properties in ol.DeviceOrientation are in radians for consistency with all other uses of angles throughout OpenLayers.

To get notified of device orientation changes, register a listener for the generic change event on your ol.DeviceOrientation instance.

new ol.DeviceOrientation(opt_options)

src/ol/deviceorientation.js, line 67
Name Type Description
options

Options.

Name Type Description
tracking boolean | undefined

Start tracking. Default is false.
Deprecated
  • This class is deprecated and will removed in the next major release.
    See:
    Fires:

    Extends

    Observable Properties

    Name Type Settable ol.Object.Event type Description
    alpha number | undefined no change:alpha

    The euler angle in radians of the device from the standard Z axis.
    beta number | undefined no change:beta

    The euler angle in radians of the device from the planar X axis.
    gamma number | undefined no change:gamma

    The euler angle in radians of the device from the planar Y axis.
    heading number | undefined no change:heading

    The heading of the device relative to north, in radians, normalizing for different browser behavior.
    tracking boolean yes change:tracking

    Changes in device orientation are being tracked.

    Methods

    changed() inherited

    src/ol/observable.js, line 58

    Increases the revision counter and dispatches a 'change' event.

    dispatchEvent(event) inherited

    src/ol/observable.js, line 75

    Dispatches an event and calls all listeners listening for events of this type. The event parameter can either be a string or an Object with a type property.

    Name Type Description
    event Object | ol.events.Event | string

    Event object.

    get(key){*} inherited

    src/ol/object.js, line 101

    Gets a value.

    Name Type Description
    key string

    Key name.
    Returns:
    Value.

    getAlpha(){number|undefined}

    src/ol/deviceorientation.js, line 135

    Rotation around the device z-axis (in radians).

    Returns:
    The euler angle in radians of the device from the standard Z axis.

    getBeta(){number|undefined}

    src/ol/deviceorientation.js, line 148

    Rotation around the device x-axis (in radians).

    Returns:
    The euler angle in radians of the device from the planar X axis.

    getGamma(){number|undefined}

    src/ol/deviceorientation.js, line 161

    Rotation around the device y-axis (in radians).

    Returns:
    The euler angle in radians of the device from the planar Y axis.

    getHeading(){number|undefined}

    src/ol/deviceorientation.js, line 174

    The heading of the device relative to north (in radians).

    Returns:
    The heading of the device relative to north, in radians, normalizing for different browser behavior.

    getKeys(){Array.<string>} inherited

    src/ol/object.js, line 115

    Get a list of object property names.

    Returns:
    List of property names.

    getProperties(){Object.<string, *>} inherited

    src/ol/object.js, line 125

    Get an object of all property names and values.

    Returns:
    Object.

    getRevision(){number} inherited

    src/ol/observable.js, line 84

    Get the version number for this object. Each time the object is modified, its version number will be incremented.

    Returns:
    Revision.

    getTracking(){boolean}

    src/ol/deviceorientation.js, line 186

    Determine if orientation is being tracked.

    Returns:
    Changes in device orientation are being tracked.

    on(type, listener, opt_this){ol.EventsKey|Array.<ol.EventsKey>} inherited

    src/ol/observable.js, line 99

    Listen for a certain type of event.

    Name Type Description
    type string | Array.<string>

    The event type or array of event types.
    listener function

    The listener function.
    this Object

    The object to use as this in listener.
    Returns:
    Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

    once(type, listener, opt_this){ol.EventsKey|Array.<ol.EventsKey>} inherited

    src/ol/observable.js, line 124

    Listen once for a certain type of event.

    Name Type Description
    type string | Array.<string>

    The event type or array of event types.
    listener function

    The listener function.
    this Object

    The object to use as this in listener.
    Returns:
    Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

    set(key, value, opt_silent) inherited

    src/ol/object.js, line 150

    Sets a value.

    Name Type Description
    key string

    Key name.
    value *

    Value.
    silent boolean

    Update without triggering an event.

    setProperties(values, opt_silent) inherited

    src/ol/object.js, line 170

    Sets a collection of key-value pairs. Note that this changes any existing properties and adds new ones (it does not remove any existing properties).

    Name Type Description
    values Object.<string, *>

    Values.
    silent boolean

    Update without triggering an event.

    setTracking(tracking)

    src/ol/deviceorientation.js, line 216

    Enable or disable tracking of device orientation events.

    Name Type Description
    tracking boolean

    The status of tracking changes to alpha, beta and gamma. If true, changes are tracked and reported immediately.

    un(type, listener, opt_this) inherited

    src/ol/observable.js, line 147

    Unlisten for a certain type of event.

    Name Type Description
    type string | Array.<string>

    The event type or array of event types.
    listener function

    The listener function.
    this Object

    The object which was used as this by the listener.

    unset(key, opt_silent) inherited

    src/ol/object.js, line 184

    Unsets a property.

    Name Type Description
    key string

    Key name.
    silent boolean

    Unset without triggering an event.