OpenLayers 3 API Documentation

Class: Control

ol.control.Control

A control is a visible widget with a DOM element in a fixed position on the screen. They can involve user input (buttons), or be informational only; the position is determined using CSS. By default these are placed in the container with CSS class name ol-overlaycontainer-stopevent, but can use any outside DOM element.

This is the base class for controls. You can use it for simple custom controls by creating the element with listeners, creating an instance:

var myControl = new ol.control.Control({element: myElement});

and then adding this to the map.

The main advantage of having this as a control rather than a simple separate DOM element is that preventing propagation is handled for you. Controls will also be ol.Objects in a ol.Collection, so you can use their methods.

You can also extend this base for your own control class. See examples/custom-controls for an example of how to do this.

new ol.control.Control(options)

src/ol/control/control.js, line 40
Name Type Description
options

Control options.

Name Type Description
element Element | undefined

The element is the control's container element. This only needs to be specified if you're developing a custom control.
render function | undefined experimental

Function called when the control should be re-rendered. This is called in a requestAnimationFrame callback.
target Element | string | undefined

Specify a target if you want the control to be rendered outside of the map's viewport.
Fires:

Subclasses

Extends

Methods

bindTo(key, target, opt_targetKey){ol.ObjectAccessor} inherited experimental

src/ol/object.js, line 326

The bindTo method allows you to set up a two-way binding between a source and target object. The method returns an object with a transform method that you can use to provide from and to functions to transform values on the way from the source to the target and on the way back.

For example, if you had two map views (sourceView and targetView) and you wanted the target view to have double the resolution of the source view, you could transform the resolution on the way to and from the target with the following:

sourceView.bindTo('resolution', targetView)
  .transform(
    function(sourceResolution) {
      // from sourceView.resolution to targetView.resolution
      return 2 * sourceResolution;
    },
    function(targetResolution) {
      // from targetView.resolution to sourceView.resolution
      return targetResolution / 2;
    }
  );
Name Type Description
key string

Key name.
target ol.Object

Target.
targetKey string

Target key.

changed() inherited experimental

src/ol/observable.js, line 52

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

Fires:
  • change experimental

get(key){*} inherited experimental

src/ol/object.js, line 354

Gets a value.

Name Type Description
key string

Key name.
Returns:
Value.

getKeys(){Array.<string>} inherited experimental

src/ol/object.js, line 373

Get a list of object property names.

Returns:
List of property names.

getMap(){ol.Map}

src/ol/control/control.js, line 95

Get the map associated with this control.

Returns:
Map.

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

src/ol/object.js, line 405

Get an object of all property names and values.

Returns:
Object.

getRevision(){number} inherited experimental

src/ol/observable.js, line 62
Returns:
Revision.

on(type, listener, opt_this){goog.events.Key} inherited

src/ol/observable.js, line 75

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.

once(type, listener, opt_this){goog.events.Key} inherited

src/ol/observable.js, line 88

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.

set(key, value) inherited experimental

src/ol/object.js, line 437

Sets a value.

Name Type Description
key string

Key name.
value *

Value.

setMap(map)

src/ol/control/control.js, line 107

Remove the control from its current map and attach it to the new map. Subclasses may set up event handlers to get notified about changes to the map here.

Name Type Description
map ol.Map

Map.

setProperties(values) inherited experimental

src/ol/object.js, line 456

Sets a collection of key-value pairs.

Name Type Description
values Object.<string, *>

Values.

setTarget(target) experimental

src/ol/control/control.js, line 138

This function is used to set a target element for the control. It has no effect if it is called after the control has been added to the map (i.e. after setMap is called on the control). If no target is set in the options passed to the control constructor and if setTarget is not called then the control is added to the map's overlay container.

Name Type Description
target Element | string

Target.

un(type, listener, opt_this) inherited

src/ol/observable.js, line 101

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.

unbind(key) inherited experimental

src/ol/object.js, line 470

Removes a binding. Unbinding will set the unbound property to the current value. The object will not be notified, as the value has not changed.

Name Type Description
key string

Key name.

unbindAll() inherited experimental

src/ol/object.js, line 487

Removes all bindings.

unByKey(key) inherited

src/ol/observable.js, line 114

Removes an event listener using the key returned by on() or once(). Note that using the ol.Observable.unByKey static function is to be preferred.

Name Type Description
key goog.events.Key

The key returned by on() or once().