OpenLayers v6.6.2-dev API

Class: Snap

ol/interaction/Snap~Snap

import Snap from 'ol/interaction/Snap';

Handles snapping of vector features while modifying or drawing them. The features can come from a module:ol/source/Vector or module:ol/Collection~Collection Any interaction object that allows the user to interact with the features using the mouse can benefit from the snapping, as long as it is added before.

The snap interaction modifies map browser event coordinate and pixel properties to force the snap to occur to any interaction that them.

Example:

import Snap from 'ol/interaction/Snap';

const snap = new Snap({
  source: source
});

map.addInteraction(snap);

new Snap(opt_options) interaction/Snap.js, line 96

Name Type Description

options

Options.

Name	Type	Description
`features`	module:ol/Collection~Collection.<module:ol/Feature~Feature>	Snap to these features. Either this option or source should be provided.
`edge`	boolean (defaults to true)	Snap to edges.
`vertex`	boolean (defaults to true)	Snap to vertices.
`pixelTolerance`	number (defaults to 10)	Pixel tolerance for considering the pointer close enough to a segment or vertex for snapping.
`source`	module:ol/source/Vector~VectorSource	Snap to features from this source. Either this option or features should be provided

Fires:

change (module:ol/events/Event~BaseEvent) - Generic change event. Triggered when the revision counter is increased.
change:active (module:ol/Object.ObjectEvent)
error (module:ol/events/Event~BaseEvent) - Generic error event. Triggered when an error occurs.
propertychange (module:ol/Object.ObjectEvent) - Triggered when a property is changed.

Extends

module:ol/interaction/Pointer~PointerInteraction

Observable Properties

Name	Type	Settable	ol/Object.ObjectEvent type	Description
`active`	boolean	yes	`change:active`	`true` if the interaction is active, `false` otherwise.

Methods

addFeature(feature, opt_listen) interaction/Snap.js, line 209

Add a feature to the collection of features that we may snap to.

Name	Type	Description
`feature`	module:ol/Feature~Feature	Feature.
`listen`	boolean	Whether to listen to the feature change or not Defaults to `true`.

changed() inherited Observable.js, line 70

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

dispatchEvent(event){boolean|undefined} inherited events/Target.js, line 85

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`	module:ol/events/Event~BaseEvent \| string	Event object.

Returns:

false if anyone called preventDefault on the event object or if any of the listeners returned false.

get(key){*} inherited Object.js, line 135

Gets a value.

Name	Type	Description
`key`	string	Key name.

Returns:

Value.

getActive(){boolean} inherited interaction/Interaction.js, line 82

Return whether the interaction is currently active.

Returns:

true if the interaction is active, false otherwise.

getKeys(){Array.<string>} inherited Object.js, line 148

Get a list of object property names.

Returns:

List of property names.

getMap(){module:ol/PluggableMap~PluggableMap} inherited interaction/Interaction.js, line 91

Get the map associated with this interaction.

Returns:

Map.

getPointerCount(){number} inherited interaction/Pointer.js, line 102

Returns the current number of pointers involved in the interaction, e.g. 2 when two fingers are used.

Returns:

The number of pointers.

getProperties(){Object.<string, *>} inherited Object.js, line 157

Get an object of all property names and values.

Returns:

Object.

getRevision(){number} inherited Observable.js, line 81

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

Returns:

Revision.

on(type, listener){module:ol/events~EventsKey|Array.<module:ol/events~EventsKey>} inherited Observable.js, line 155

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.

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){module:ol/events~EventsKey|Array.<module:ol/events~EventsKey>} inherited Observable.js, line 167

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.

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.

removeFeature(feature, opt_unlisten) interaction/Snap.js, line 331

Remove a feature from the collection of features that we may snap to.

Name	Type	Description
`feature`	module:ol/Feature~Feature	Feature
`unlisten`	boolean	Whether to unlisten to the feature change or not. Defaults to `true`.

set(key, value, opt_silent) inherited Object.js, line 203

Sets a value.

Name	Type	Description
`key`	string	Key name.
`value`	*	Value.
`silent`	boolean	Update without triggering an event.

setActive(active) inherited interaction/Interaction.js, line 111

Activate or deactivate the interaction.

Name	Type	Description
`active`	boolean	Active.

setProperties(values, opt_silent) inherited Object.js, line 223

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.

un(type, listener) inherited Observable.js, line 176

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.

unset(key, opt_silent) inherited Object.js, line 247

Unsets a property.

Name	Type	Description
`key`	string	Key name.
`silent`	boolean	Unset without triggering an event.