Controls affect the display or behavior of the map. They allow everything from panning and zooming to displaying a scale indicator. Controls by default are added to the map they are contained within however it is possible to add a control to an external div by passing the div in the options parameter.
The following example shows how to add many of the common controls to a map.
var map = new OpenLayers.Map('map', { controls: [] });
map.addControl(new OpenLayers.Control.PanZoomBar());
map.addControl(new OpenLayers.Control.MouseToolbar());
map.addControl(new OpenLayers.Control.LayerSwitcher({'ascending':false}));
map.addControl(new OpenLayers.Control.Permalink());
map.addControl(new OpenLayers.Control.Permalink('permalink'));
map.addControl(new OpenLayers.Control.MousePosition());
map.addControl(new OpenLayers.Control.OverviewMap());
map.addControl(new OpenLayers.Control.KeyboardDefaults());The next code fragment is a quick example of how to intercept shift-mouse click to display the extent of the bounding box dragged out by the user. Usually controls are not created in exactly this manner. See the source for a more complete example:
var control = new OpenLayers.Control();
OpenLayers.Util.extend(control, {
draw: function () {
// this Handler.Box will intercept the shift-mousedown
// before Control.MouseDefault gets to see it
this.box = new OpenLayers.Handler.Box( control,
{"done": this.notice},
{keyMask: OpenLayers.Handler.MOD_SHIFT});
this.box.activate();
},
notice: function (bounds) {
OpenLayers.Console.userError(bounds);
}
});
map.addControl(control);| OpenLayers. | Controls affect the display or behavior of the map. |
| Properties | |
| id | {String} |
| map | {OpenLayers.Map} this gets set in the addControl() function in OpenLayers.Map |
| div | {DOMElement} The element that contains the control, if not present the control is placed inside the map. |
| type | {Number} Controls can have a ‘type’. |
| allowSelection | {Boolean} By deafault, controls do not allow selection, because it may interfere with map dragging. |
| displayClass | {string} This property is used for CSS related to the drawing of the Control. |
| title | {string} This property is used for showing a tooltip over the Control. |
| autoActivate | {Boolean} Activate the control when it is added to a map. |
| active | {Boolean} The control is active (read-only). |
| handler | {OpenLayers.Handler} null |
| eventListeners | {Object} If set as an option at construction, the eventListeners object will be registered with OpenLayers.Events.on. |
| events | {OpenLayers.Events} Events instance for listeners and triggering control specific events. |
| Constants | |
| EVENT_TYPES | {Array(String)} Supported application event types. |
| Constructor | |
| OpenLayers. | Create an OpenLayers Control. |
| Functions | |
| destroy | The destroy method is used to perform any clean up before the control is dereferenced. |
| setMap | Set the map property for the control. |
| draw | The draw method is called when the control is ready to be displayed on the page. |
| moveTo | Sets the left and top style attributes to the passed in pixel coordinates. |
| activate | Explicitly activates a control and it’s associated handler if one has been set. |
| deactivate | Deactivates a control and it’s associated handler if any. |
| Constants | |
| OpenLayers. | |
| OpenLayers. | |
| OpenLayers. |
{OpenLayers.Map} this gets set in the addControl() function in OpenLayers.Map
{Number} Controls can have a ‘type’. The type determines the type of interactions which are possible with them when they are placed in an OpenLayers.Control.Panel.
{Boolean} The control is active (read-only). Use activate and deactivate to change control state.
{OpenLayers.Handler} null
{Object} If set as an option at construction, the eventListeners object will be registered with OpenLayers.Events.on. Object structure must be a listeners object as shown in the example for the events.on method.
{OpenLayers.Events} Events instance for listeners and triggering control specific events.
{Array(String)} Supported application event types. Register a listener for a particular event with the following syntax:
control.events.register(type, obj, listener);
Listeners will be called with a reference to an event object. The properties of this event depends on exactly what happened.
| object | {Object} A reference to control.events.object (a reference to the control). |
| element | {DOMElement} A reference to control.events.element (which will be null unless documented otherwise). |
| activate | Triggered when activated. |
| deactivate | Triggered when deactivated. |
setMap: function( map )
Set the map property for the control. This is done through an accessor so that subclasses can override this and take special action once they have their map variable set.
| map | {OpenLayers.Map} |
draw: function ( px )
The draw method is called when the control is ready to be displayed on the page. If a div has not been created one is created. Controls with a visual component will almost always want to override this method to customize the look of control.
| px | {OpenLayers.Pixel} The top-left pixel position of the control or null. |
{DOMElement} A reference to the DIV DOMElement containing the control
moveTo: function ( px )
Sets the left and top style attributes to the passed in pixel coordinates.
| px | {OpenLayers.Pixel} |
Convenience method for registering listeners with a common scope.
on: function( object )
The destroy method is used to perform any clean up before the control is dereferenced.
destroy: function ()
Set the map property for the control.
setMap: function( map )
The draw method is called when the control is ready to be displayed on the page.
draw: function ( px )
Sets the left and top style attributes to the passed in pixel coordinates.
moveTo: function ( px )
Explicitly activates a control and it’s associated handler if one has been set.
activate: function ()
Deactivates a control and it’s associated handler if any.
deactivate: function ()