openlayers
Version:
Build tools and sources for developing OpenLayers based mapping applications
229 lines (199 loc) • 7.38 kB
JavaScript
goog.provide('ol.DeviceOrientation');
goog.require('ol.events');
goog.require('ol');
goog.require('ol.Object');
goog.require('ol.has');
goog.require('ol.math');
/**
* @classdesc
* The ol.DeviceOrientation class provides access to information from
* DeviceOrientation events. See the [HTML 5 DeviceOrientation Specification](
* http://www.w3.org/TR/orientation-event/) 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.
*
* @see {@link http://www.w3.org/TR/orientation-event/}
*
* @constructor
* @extends {ol.Object}
* @param {olx.DeviceOrientationOptions=} opt_options Options.
* @api
*/
ol.DeviceOrientation = function(opt_options) {
ol.Object.call(this);
var options = opt_options ? opt_options : {};
/**
* @private
* @type {?ol.EventsKey}
*/
this.listenerKey_ = null;
ol.events.listen(this,
ol.Object.getChangeEventType(ol.DeviceOrientation.Property.TRACKING),
this.handleTrackingChanged_, this);
this.setTracking(options.tracking !== undefined ? options.tracking : false);
};
ol.inherits(ol.DeviceOrientation, ol.Object);
/**
* @inheritDoc
*/
ol.DeviceOrientation.prototype.disposeInternal = function() {
this.setTracking(false);
ol.Object.prototype.disposeInternal.call(this);
};
/**
* @private
* @param {Event} originalEvent Event.
*/
ol.DeviceOrientation.prototype.orientationChange_ = function(originalEvent) {
var event = /** @type {DeviceOrientationEvent} */ (originalEvent);
if (event.alpha !== null) {
var alpha = ol.math.toRadians(event.alpha);
this.set(ol.DeviceOrientation.Property.ALPHA, alpha);
// event.absolute is undefined in iOS.
if (typeof event.absolute === 'boolean' && event.absolute) {
this.set(ol.DeviceOrientation.Property.HEADING, alpha);
} else if (typeof event.webkitCompassHeading === 'number' &&
event.webkitCompassAccuracy != -1) {
var heading = ol.math.toRadians(event.webkitCompassHeading);
this.set(ol.DeviceOrientation.Property.HEADING, heading);
}
}
if (event.beta !== null) {
this.set(ol.DeviceOrientation.Property.BETA,
ol.math.toRadians(event.beta));
}
if (event.gamma !== null) {
this.set(ol.DeviceOrientation.Property.GAMMA,
ol.math.toRadians(event.gamma));
}
this.changed();
};
/**
* Rotation around the device z-axis (in radians).
* @return {number|undefined} The euler angle in radians of the device from the
* standard Z axis.
* @observable
* @api
*/
ol.DeviceOrientation.prototype.getAlpha = function() {
return /** @type {number|undefined} */ (
this.get(ol.DeviceOrientation.Property.ALPHA));
};
/**
* Rotation around the device x-axis (in radians).
* @return {number|undefined} The euler angle in radians of the device from the
* planar X axis.
* @observable
* @api
*/
ol.DeviceOrientation.prototype.getBeta = function() {
return /** @type {number|undefined} */ (
this.get(ol.DeviceOrientation.Property.BETA));
};
/**
* Rotation around the device y-axis (in radians).
* @return {number|undefined} The euler angle in radians of the device from the
* planar Y axis.
* @observable
* @api
*/
ol.DeviceOrientation.prototype.getGamma = function() {
return /** @type {number|undefined} */ (
this.get(ol.DeviceOrientation.Property.GAMMA));
};
/**
* The heading of the device relative to north (in radians).
* @return {number|undefined} The heading of the device relative to north, in
* radians, normalizing for different browser behavior.
* @observable
* @api
*/
ol.DeviceOrientation.prototype.getHeading = function() {
return /** @type {number|undefined} */ (
this.get(ol.DeviceOrientation.Property.HEADING));
};
/**
* Determine if orientation is being tracked.
* @return {boolean} Changes in device orientation are being tracked.
* @observable
* @api
*/
ol.DeviceOrientation.prototype.getTracking = function() {
return /** @type {boolean} */ (
this.get(ol.DeviceOrientation.Property.TRACKING));
};
/**
* @private
*/
ol.DeviceOrientation.prototype.handleTrackingChanged_ = function() {
if (ol.has.DEVICE_ORIENTATION) {
var tracking = this.getTracking();
if (tracking && !this.listenerKey_) {
this.listenerKey_ = ol.events.listen(window, 'deviceorientation',
this.orientationChange_, this);
} else if (!tracking && this.listenerKey_ !== null) {
ol.events.unlistenByKey(this.listenerKey_);
this.listenerKey_ = null;
}
}
};
/**
* Enable or disable tracking of device orientation events.
* @param {boolean} tracking The status of tracking changes to alpha, beta and
* gamma. If true, changes are tracked and reported immediately.
* @observable
* @api
*/
ol.DeviceOrientation.prototype.setTracking = function(tracking) {
this.set(ol.DeviceOrientation.Property.TRACKING, tracking);
};
/**
* @enum {string}
*/
ol.DeviceOrientation.Property = {
ALPHA: 'alpha',
BETA: 'beta',
GAMMA: 'gamma',
HEADING: 'heading',
TRACKING: 'tracking'
};