labs.style.PixelDensityMonitor Extends goog.events.EventTarget
Monitors the window for changes to the ratio between device and screen pixels, e.g. when the user moves the window from a high density screen to a screen with normal density. Dispatches goog.labs.style.PixelDensityMonitor.EventType.CHANGE events when the density changes between the two predefined values NORMAL and HIGH. This class uses the window.devicePixelRatio value which is supported in WebKit and FF18. If the value does not exist, it will always return a NORMAL density. It requires support for MediaQueryList to detect changes to the devicePixelRatio.

Inheritance

Constructor

goog.labs.style.PixelDensityMonitor(opt_domHelper)

Parameters

opt_domHelper : !goog.dom.DomHelper=
The DomHelper which contains the document associated with the window to listen to. Defaults to the one in which this code is executing.

Instance Methods

Public Protected Private
disposeInternal()
No description.
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getDensity() goog.labs.style.PixelDensityMonitor.Density
No description.
Returns: goog.labs.style.PixelDensityMonitor.Density  The density for the window.
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handleMediaQueryChange_(mql)
Handles a change to the media query and checks whether the density has changed since the last call.
Arguments:
mql : MediaQueryList
The list of changed media queries.
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listener_()
No description.
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start()
Starts monitoring for changes in pixel density.
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addEventListener(typeopt_captureopt_handlerScope)
Use #listen instead, when possible. Otherwise, use goog.events.listen if you are passing Object (instead of Function) as handler. Adds an event listener to the event target. The same handler can only be added once per the type. Even if you add the same handler multiple times using the same type then it will only be called once when the event is dispatched.
Arguments:
type : string
The type of the event to listen for.
: ?function():? | ?{handleEvent:function():?
No description.
opt_capture : boolean=
In DOM-compliant browsers, this determines whether the listener is fired during the capture or bubble phase of the event.
opt_handlerScope : Object=
Object in whose scope to call the listener.
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assertInitialized_()
Asserts that the event target instance is initialized properly.
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dispatchEvent()
No description.
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disposeInternal()
Removes listeners from this object. Classes that extend EventTarget may need to override this method in order to remove references to DOM Elements and additional listeners.
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fireListeners()
No description.
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getListener()
No description.
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getListeners()
No description.
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getParentEventTarget() goog.events.EventTarget
Returns the parent of this event target to use for bubbling.
Returns: goog.events.EventTarget  The parent EventTarget or null if there is no parent.
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hasListener()
No description.
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listen()
No description.
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listenOnce()
No description.
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removeAllListeners()
No description.
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removeEventListener(typeopt_captureopt_handlerScope)
Use #unlisten instead, when possible. Otherwise, use goog.events.unlisten if you are passing Object (instead of Function) as handler. Removes an event listener from the event target. The handler must be the same object as the one added. If the handler has not been added then nothing is done.
Arguments:
type : string
The type of the event to listen for.
: ?function():? | ?{handleEvent:function():?
No description.
opt_capture : boolean=
In DOM-compliant browsers, this determines whether the listener is fired during the capture or bubble phase of the event.
opt_handlerScope : Object=
Object in whose scope to call the listener.
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setParentEventTarget(parent)
Sets the parent of this event target to use for capture/bubble mechanism.
Arguments:
parent : goog.events.EventTarget
Parent listenable (null if none).
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setTargetForTesting(target)
Sets the target to be used for event.target when firing event. Mainly used for testing. For example, see goog.testing.events.mixinListenable.
Arguments:
target : !Object
The target.
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unlisten()
No description.
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unlistenByKey()
No description.
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addOnDisposeCallback(callbackopt_scope)
Invokes a callback function when this object is disposed. Callbacks are invoked in the order in which they were added.
Arguments:
callback : function(this:T):?
The callback function.
opt_scope : T=
An optional scope to call the callback in.
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dispose() void
Disposes of the object. If the object hasn't already been disposed of, calls #disposeInternal. Classes that extend goog.Disposable should override #disposeInternal in order to delete references to COM objects, DOM nodes, and other disposable objects. Reentrant.
Returns: void  Nothing.
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disposeInternal()
Deletes or nulls out any references to COM objects, DOM nodes, or other disposable objects. Classes that extend goog.Disposable should override this method. Not reentrant. To avoid calling it twice, it must only be called from the subclass' disposeInternal method. Everywhere else the public dispose method must be used. For example:
  mypackage.MyClass = function() {
    mypackage.MyClass.base(this, 'constructor');
    // Constructor logic specific to MyClass.
    ...
  };
  goog.inherits(mypackage.MyClass, goog.Disposable);

  mypackage.MyClass.prototype.disposeInternal = function() {
    // Dispose logic specific to MyClass.
    ...
    // Call superclass's disposeInternal at the end of the subclass's, like
    // in C++, to avoid hard-to-catch issues.
    mypackage.MyClass.base(this, 'disposeInternal');
  };
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getDisposed() boolean
Use #isDisposed instead. No description.
Returns: boolean  Whether the object has been disposed of.
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isDisposed() boolean
No description.
Returns: boolean  Whether the object has been disposed of.
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registerDisposable(disposable)
Associates a disposable object with this object so that they will be disposed together.
Arguments:
disposable : goog.disposable.IDisposable
that will be disposed when this object is disposed.
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Instance Properties

constructor :
No description.
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lastDensity_ :
The last density that was reported so that changes can be detected.
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mediaQueryList_ :
The media query list for a query that detects high density, if supported by the browser. Because matchMedia returns a new object for every call, it needs to be saved here so the listener can be removed when disposing.
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window_ :
No description.
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actualEventTarget_ : goog.events.EventTarget
The object to use for event.target. Useful when mixing in an EventTarget to another object.
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constructor :
No description.
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eventTargetListeners_ : goog.events.ListenerMap
Maps of event type to an array of listeners.
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parentEventTarget_ : goog.events.EventTarget
Parent event target, used during event bubbling. TODO(user): Change this to goog.events.Listenable. This currently breaks people who expect getParentEventTarget to return goog.events.EventTarget.
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creationStack :
If monitoring the goog.Disposable instances is enabled, stores the creation stack trace of the Disposable instance.
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disposed_ :
Whether the object has been disposed of.
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onDisposeCallbacks_ :
Callbacks to invoke when this object is disposed.
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Static Properties

goog.labs.style.PixelDensityMonitor.HIGH_DENSITY_QUERY_ :
Media query that matches for high density.
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goog.labs.style.PixelDensityMonitor.HIGH_DENSITY_RATIO_ :
Minimum ratio between device and screen pixel needed for high density mode.
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goog.labs.style.PixelDensityMonitor.superClass_ :
No description.
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Enumerations

goog.labs.style.PixelDensityMonitor.Density :
The two different pixel density modes on which the various ratios between physical and device pixels are mapped.
Constants:
HIGH
No description.
NORMAL
No description.
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goog.labs.style.PixelDensityMonitor.EventType :
The events fired by the PixelDensityMonitor.
Constants:
CHANGE
No description.
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Package labs.style

Package Reference