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 229
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.

Methods

animate(var_args)

View.js, line 411

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

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.

Name Type Default Description
center module:ol/coordinate~Coordinate | undefined

The center of the view at the end of the animation.

zoom number | undefined

The zoom level of the view at the end of the animation. This takes precedence over resolution.

resolution number | undefined

The resolution of the view at the end of the animation. If zoom is also provided, this option will be ignored.

rotation number | undefined

The rotation of the view at the end of the animation.

anchor module:ol/coordinate~Coordinate | undefined

Optional anchor to remained fixed during a rotation or resolution animation.

duration number 1000

The duration of the animation in milliseconds.

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.

calculateExtent(opt_size){module:ol/extent~Extent}

View.js, line 732

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 513

Cancel any ongoing animations.

centerOn(coordinate, size, position)

View.js, line 1084

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.

constrainCenter(center){module:ol/coordinate~Coordinate|undefined}

View.js, line 659

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 671

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 684

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 982

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.

getAnimating(){boolean}

View.js, line 496

Determine if the view is being animated.

Returns:
The view is being animated.

getCenter(){module:ol/coordinate~Coordinate|undefined}

View.js, line 695

Get the view center.

Returns:
The center of the view.

getInteracting(){boolean}

View.js, line 505

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

Returns:
The view is being interacted with.

getMaxResolution(){number}

View.js, line 749

Get the maximum resolution of the view.

Returns:
The maximum resolution of the view.

getMaxZoom(){number}

View.js, line 767

Get the maximum zoom level for the view.

Returns:
The maximum zoom level.

getMinResolution(){number}

View.js, line 758

Get the minimum resolution of the view.

Returns:
The minimum resolution of the view.

getMinZoom(){number}

View.js, line 785

Get the minimum zoom level for the view.

Returns:
The minimum zoom level.

getProjection(){module:ol/proj/Projection~Projection}

View.js, line 803

Get the view projection.

Returns:
The projection of the view.

getResolution(){number|undefined}

View.js, line 813

Get the view resolution.

Returns:
The resolution of the view.

getResolutionForExtent(extent, opt_size){number}

View.js, line 835

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 967

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 823

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.

getRotation(){number}

View.js, line 870

Get the view rotation.

Returns:
The rotation of the view in radians.

getZoom(){number|undefined}

View.js, line 927

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 942

Get the zoom level for a resolution.

Name Type Description
resolution number

The resolution.

Returns:
The zoom level for the provided resolution.

rotate(rotation, opt_anchor)

View.js, line 1116

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.

setCenter(center)

View.js, line 1130

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 776

Set a new maximum zoom level for the view.

Name Type Description
zoom number

The maximum zoom level.

setMinZoom(zoom)

View.js, line 794

Set a new minimum zoom level for the view.

Name Type Description
zoom number

The minimum zoom level.

setResolution(resolution)

View.js, line 1154

Set the resolution for this view.

Name Type Description
resolution number | undefined

The resolution of the view.

setRotation(rotation)

View.js, line 1167

Set the rotation for this view.

Name Type Description
rotation number

The rotation of the view in radians.

setZoom(zoom)

View.js, line 1179

Zoom to a specific zoom level.

Name Type Description
zoom number

Zoom level.