Class: View

ol/View~View

import View from 'ol/View';

A View object represents a simple 2D view of the map.

This is the object to act upon to change the center, resolution, and rotation of the map.

The view states

An View is determined by three states: center, resolution, and rotation. Each state has a corresponding getter and setter, e.g. getCenter and setCenter for the center state.

An View has a projection. The projection determines the coordinate system of the center, and its units determine the units of the resolution (projection units per pixel). The default projection is Spherical Mercator (EPSG:3857).

The constraints

setCenter, setResolution and setRotation can be used to change the states of the view. Any value can be passed to the setters. And the value that is passed to a setter will effectively be the value set in the view, and returned by the corresponding getter.

But a View object also has a resolution constraint, a rotation constraint and a center constraint.

As said above, no constraints are applied when the setters are used to set new states for the view. Applying constraints is done explicitly through the use of the constrain* functions (constrainResolution and constrainRotation and constrainCenter).

The main users of the constraints are the interactions and the controls. For example, double-clicking on the map changes the view to the "next" resolution. And releasing the fingers after pinch-zooming snaps to the closest resolution (with an animation).

The resolution constraint snaps to specific resolutions. It is determined by the following options: resolutions, maxResolution, maxZoom, and zoomFactor. If resolutions is set, the other three options are ignored. See documentation for each option for more information.

The rotation constraint snaps to specific angles. It is determined by the following options: enableRotation and constrainRotation. By default the rotation value is snapped to zero when approaching the horizontal.

The center constraint is determined by the extent option. By default the center is not constrained at all.

new View(opt_options)

View.js, line 228

Name Type Description

options

View options.

Name	Type	Default	Description
`center`	module:ol/coordinate~Coordinate		The initial center for the view. The coordinate system for the center is specified with the `projection` option. Layer sources will not be fetched if this is not set, but the center can be set later with `#setCenter`.
`constrainRotation`	boolean \| number	true	Rotation constraint. `false` means no constraint. `true` means no constraint, but snap to zero near zero. A number constrains the rotation to that number of values. For example, `4` will constrain the rotation to 0, 90, 180, and 270 degrees.
`enableRotation`	boolean	true	Enable rotation. If `false`, a rotation constraint that always sets the rotation to zero is used. The `constrainRotation` option has no effect if `enableRotation` is `false`.
`extent`	module:ol/extent~Extent		The extent that constrains the center, in other words, center cannot be set outside this extent.
`maxResolution`	number		The maximum resolution used to determine the resolution constraint. It is used together with `minResolution` (or `maxZoom`) and `zoomFactor`. If unspecified it is calculated in such a way that the projection's validity extent fits in a 256x256 px tile. If the projection is Spherical Mercator (the default) then `maxResolution` defaults to `40075016.68557849 / 256 = 156543.03392804097`.
`minResolution`	number		The minimum resolution used to determine the resolution constraint. It is used together with `maxResolution` (or `minZoom`) and `zoomFactor`. If unspecified it is calculated assuming 29 zoom levels (with a factor of 2). If the projection is Spherical Mercator (the default) then `minResolution` defaults to `40075016.68557849 / 256 / Math.pow(2, 28) = 0.0005831682455839253`.
`maxZoom`	number	28	The maximum zoom level used to determine the resolution constraint. It is used together with `minZoom` (or `maxResolution`) and `zoomFactor`. Note that if `minResolution` is also provided, it is given precedence over `maxZoom`.
`minZoom`	number	0	The minimum zoom level used to determine the resolution constraint. It is used together with `maxZoom` (or `minResolution`) and `zoomFactor`. Note that if `maxResolution` is also provided, it is given precedence over `minZoom`.
`projection`	module:ol/proj~ProjectionLike	'EPSG:3857'	The projection. The default is Spherical Mercator.
`resolution`	number		The initial resolution for the view. The units are `projection` units per pixel (e.g. meters per pixel). An alternative to setting this is to set `zoom`. Layer sources will not be fetched if neither this nor `zoom` are defined, but they can be set later with `#setZoom` or `#setResolution`.
`resolutions`	Array.<number>		Resolutions to determine the resolution constraint. If set the `maxResolution`, `minResolution`, `minZoom`, `maxZoom`, and `zoomFactor` options are ignored.
`rotation`	number	0	The initial rotation for the view in radians (positive rotation clockwise, 0 means North).
`zoom`	number		Only used if `resolution` is not defined. Zoom level used to calculate the initial resolution for the view. The initial resolution is determined using the `#constrainResolution` method.
`zoomFactor`	number	2	The zoom factor used to determine the resolution constraint.

Fires:

change (module:ol/events/Event~Event) - Generic change event. Triggered when the revision counter is increased.
change:center (module:ol/Object.ObjectEvent)
change:resolution (module:ol/Object.ObjectEvent)
change:rotation (module:ol/Object.ObjectEvent)
propertychange (module:ol/Object.ObjectEvent) - Triggered when a property is changed.

Extends

module:ol/Object~BaseObject

Observable Properties

Name	Type	Settable	ol/Object.ObjectEvent type	Description
`center`	module:ol/coordinate~Coordinate \| undefined	yes	`change:center`	The center of the view.
`resolution`	number \| undefined	yes	`change:resolution`	The resolution of the view.
`rotation`	number	yes	`change:rotation`	The rotation of the view in radians.

Methods

animate(var_args) View.js, line 410

Animate the view. The view's center, zoom (or resolution), and rotation can be animated for smooth transitions between view states. For example, to animate the view to a new zoom level:

view.animate({zoom: view.getZoom() + 1});

By default, the animation lasts one second and uses in-and-out easing. You can customize this behavior by including duration (in milliseconds) and easing options (see module:ol/easing).

To chain together multiple animations, call the method with multiple animation objects. For example, to first zoom and then pan:

view.animate({zoom: 10}, {center: [0, 0]});

If you provide a function as the last argument to the animate method, it will get called at the end of an animation series. The callback will be called with true if the animation series completed on its own or false if it was cancelled.

Animations are cancelled by user interactions (e.g. dragging the map) or by calling view.setCenter(), view.setResolution(), or view.setRotation() (or another method that calls one of these).

Name	Type	Description
`var_args`	AnimationOptions \| function	Animation options. Multiple animations can be run in series by passing multiple options objects. To run multiple animations in parallel, call the method multiple times. An optional callback can be provided as a final argument. The callback will be called with a boolean indicating whether the animation completed without being cancelled.

calculateExtent(opt_size){module:ol/extent~Extent} View.js, line 731

Calculate the extent for the current view state and the passed size. The size is the pixel dimensions of the box into which the calculated extent should fit. In most cases you want to get the extent of the entire map, that is map.getSize().

Name	Type	Description
`size`	module:ol/size~Size	Box pixel size. If not provided, the size of the first map that uses this view will be used.

Returns:

Extent.

cancelAnimations() View.js, line 512

Cancel any ongoing animations.

centerOn(coordinate, size, position) View.js, line 1083

Center on coordinate and view position.

Name	Type	Description
`coordinate`	module:ol/coordinate~Coordinate	Coordinate.
`size`	module:ol/size~Size	Box pixel size.
`position`	module:ol/pixel~Pixel	Position on the view to center on.

changed() inherited Observable.js, line 36

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

constrainCenter(center){module:ol/coordinate~Coordinate|undefined} View.js, line 658

Get the constrained center of this view.

Name	Type	Description
`center`	module:ol/coordinate~Coordinate \| undefined	Center.

Returns:

Constrained center.

constrainResolution(resolution, opt_delta, opt_direction){number|undefined} View.js, line 670

Get the constrained resolution of this view.

Name	Type	Description
`resolution`	number \| undefined	Resolution.
`delta`	number	Delta. Default is `0`.
`direction`	number	Direction. Default is `0`.

Returns:

Constrained resolution.

constrainRotation(rotation, opt_delta){number|undefined} View.js, line 683

Get the constrained rotation of this view.

Name	Type	Description
`rotation`	number \| undefined	Rotation.
`delta`	number	Delta. Default is `0`.

Returns:

Constrained rotation.

fit(geometryOrExtent, opt_options) View.js, line 981

Fit the given geometry or extent based on the given map size and border. The size is pixel dimensions of the box to fit the extent into. In most cases you will want to use the map size, that is map.getSize(). Takes care of the map angle.

Name Type Description

geometryOrExtent

module:ol/geom/SimpleGeometry~SimpleGeometry | module:ol/extent~Extent

The geometry or extent to fit the view to.

options

Options.

Name	Type	Default	Description
`size`	module:ol/size~Size		The size in pixels of the box to fit the extent into. Default is the current size of the first map in the DOM that uses this view, or `[100, 100]` if no such map is found.
`padding`	Array.<number>	[0, 0, 0, 0]	Padding (in pixels) to be cleared inside the view. Values in the array are top, right, bottom and left padding.
`constrainResolution`	boolean	true	Constrain the resolution.
`nearest`	boolean	false	If `constrainResolution` is `true`, get the nearest extent instead of the closest that actually fits the view.
`minResolution`	number	0	Minimum resolution that we zoom to.
`maxZoom`	number		Maximum zoom level that we zoom to. If `minResolution` is given, this property is ignored.
`duration`	number		The duration of the animation in milliseconds. By default, there is no animation to the target extent.
`easing`	function		The easing function used during the animation (defaults to `module:ol/easing~inAndOut`). The function will be called for each frame with a number representing a fraction of the animation's duration. The function should return a number between 0 and 1 representing the progress toward the destination state.
`callback`	function		Function called when the view is in its final position. The callback will be called with `true` if the animation series completed on its own or `false` if it was cancelled.

get(key){*} inherited Object.js, line 119

Gets a value.

Name	Type	Description
`key`	string	Key name.

Returns:

Value.

getAnimating(){boolean} View.js, line 495

Determine if the view is being animated.

Returns:

The view is being animated.

getCenter(){module:ol/coordinate~Coordinate|undefined} View.js, line 694

Get the view center.

Returns:

The center of the view.

getInteracting(){boolean} View.js, line 504

Determine if the user is interacting with the view, such as panning or zooming.

Returns:

The view is being interacted with.

getKeys(){Array.<string>} inherited Object.js, line 132

Get a list of object property names.

Returns:

List of property names.

getMaxResolution(){number} View.js, line 748

Get the maximum resolution of the view.

Returns:

The maximum resolution of the view.

getMaxZoom(){number} View.js, line 766

Get the maximum zoom level for the view.

Returns:

The maximum zoom level.

getMinResolution(){number} View.js, line 757

Get the minimum resolution of the view.

Returns:

The minimum resolution of the view.

getMinZoom(){number} View.js, line 784

Get the minimum zoom level for the view.

Returns:

The minimum zoom level.

getProjection(){module:ol/proj/Projection~Projection} View.js, line 802

Get the view projection.

Returns:

The projection of the view.

getProperties(){Object.<string, *>} inherited Object.js, line 141

Get an object of all property names and values.

Returns:

Object.

getResolution(){number|undefined} View.js, line 812

Get the view resolution.

Returns:

The resolution of the view.

getResolutionForExtent(extent, opt_size){number} View.js, line 834

Get the resolution for a provided extent (in map units) and size (in pixels).

Name	Type	Description
`extent`	module:ol/extent~Extent	Extent.
`size`	module:ol/size~Size	Box pixel size.

Returns:

The resolution at which the provided extent will render at the given size.

getResolutionForZoom(zoom){number} View.js, line 966

Get the resolution for a zoom level.

Name	Type	Description
`zoom`	number	Zoom level.

Returns:

The view resolution for the provided zoom level.

getResolutions(){Array.<number>|undefined} View.js, line 822

Get the resolutions for the view. This returns the array of resolutions passed to the constructor of the View, or undefined if none were given.

Returns:

The resolutions of the view.

getRevision(){number} inherited Observable.js, line 47

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

Returns:

Revision.

getRotation(){number} View.js, line 869

Get the view rotation.

Returns:

The rotation of the view in radians.

getZoom(){number|undefined} View.js, line 926

Get the current zoom level. If you configured your view with a resolutions array (this is rare), this method may return non-integer zoom levels (so the zoom level is not safe to use as an index into a resolutions array).

Returns:

Zoom.

getZoomForResolution(resolution){number|undefined} View.js, line 941

Get the zoom level for a resolution.

Name	Type	Description
`resolution`	number	The resolution.

Returns:

The zoom level for the provided resolution.

on(type, listener){module:ol/events~EventsKey|Array.<module:ol/events~EventsKey>} inherited Observable.js, line 60

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 82

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.

rotate(rotation, opt_anchor) View.js, line 1115

Rotate the view around a given coordinate.

Name	Type	Description
`rotation`	number	New rotation value for the view.
`anchor`	module:ol/coordinate~Coordinate	The rotation center.

set(key, value, opt_silent) inherited Object.js, line 164

Sets a value.

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

setCenter(center) View.js, line 1129

Set the center of the current view.

Name	Type	Description
`center`	module:ol/coordinate~Coordinate \| undefined	The center of the view.

setMaxZoom(zoom) View.js, line 775

Set a new maximum zoom level for the view.

Name	Type	Description
`zoom`	number	The maximum zoom level.

setMinZoom(zoom) View.js, line 793

Set a new minimum zoom level for the view.

Name	Type	Description
`zoom`	number	The minimum zoom level.

setProperties(values, opt_silent) inherited Object.js, line 183

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.

setResolution(resolution) View.js, line 1153

Set the resolution for this view.

Name	Type	Description
`resolution`	number \| undefined	The resolution of the view.

setRotation(rotation) View.js, line 1166

Set the rotation for this view.

Name	Type	Description
`rotation`	number	The rotation of the view in radians.

setZoom(zoom) View.js, line 1178

Zoom to a specific zoom level.

Name	Type	Description
`zoom`	number	Zoom level.

un(type, listener) inherited 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.

unset(key, opt_silent) inherited Object.js, line 195

Unsets a property.

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