OpenLayers

Class: CanvasMap

ol.CanvasMap 


import CanvasMap from 'ol/canvasmap';

The map is the core component of OpenLayers. For a map to render, a view, one or more layers, and a target container are needed:

var map = new ol.CanvasMap({
  view: new ol.View({
    center: [0, 0],
    zoom: 1
  }),
  layers: [
    new ol.layer.Tile({
      source: new ol.source.OSM()
    })
  ],
  target: 'map'
});

The above snippet creates a map using a ol.layer.Tile to display ol.source.OSM OSM data and render it to a DOM element with the id map.

The constructor places a viewport container (with CSS class name ol-viewport) in the target element (see getViewport()), and then two further elements within the viewport: one with CSS class name ol-overlaycontainer-stopevent for controls and some overlays, and one with CSS class name ol-overlaycontainer for other overlays (see the stopEvent option of ol.Overlay for the difference). The map itself is placed in a further element within the viewport.

Layers are stored as a ol.Collection in layerGroups. A top-level group is provided by the library. This is what is accessed by getLayerGroup and setLayerGroup. Layers entered in the options are added to this group, and addLayer and removeLayer change the layer collection in the group. getLayers is a convenience function for getLayerGroup().getLayers(). Note that ol.layer.Group is a subclass of ol.layer.Base, so layers entered in the options or added with addLayer can be groups, which can contain further groups, and so on.

new ol.CanvasMap(options)

src/ol/canvasmap.js, line 74
Name Type Description
options

Map options.

Name Type Description
controls ol.Collection.<ol.control.Control> | Array.<ol.control.Control> | undefined

Controls initially added to the map. If not specified, ol.control.defaults() is used.
pixelRatio number | undefined

The ratio between physical pixels and device-independent pixels (dips) on the device. If undefined then it gets set by using window.devicePixelRatio.
interactions ol.Collection.<ol.interaction.Interaction> | Array.<ol.interaction.Interaction> | undefined

Interactions that are initially added to the map. If not specified, ol.interaction.defaults() is used.
keyboardEventTarget Element | Document | string | undefined

The element to listen to keyboard events on. This determines when the KeyboardPan and KeyboardZoom interactions trigger. For example, if this option is set to document the keyboard interactions will always trigger. If this option is not specified, the element the library listens to keyboard events on is the map target (i.e. the user-provided div for the map). If this is not document the target element needs to be focused for key events to be emitted, requiring that the target element has a tabindex attribute.
layers Array.<ol.layer.Base> | ol.Collection.<ol.layer.Base> | undefined

Layers. If this is not defined, a map with no layers will be rendered. Note that layers are rendered in the order supplied, so if you want, for example, a vector layer to appear on top of a tile layer, it must come after the tile layer.
loadTilesWhileAnimating boolean | undefined

When set to true, tiles will be loaded during animations. This may improve the user experience, but can also make animations stutter on devices with slow memory. Default is false.
loadTilesWhileInteracting boolean | undefined

When set to true, tiles will be loaded while interacting with the map. This may improve the user experience, but can also make map panning and zooming choppy on devices with slow memory. Default is false.
logo boolean | string | olx.LogoOptions | Element | undefined

The map logo. A logo to be displayed on the map at all times. If a string is provided, it will be set as the image source of the logo. If an object is provided, the src property should be the URL for an image and the href property should be a URL for creating a link. If an element is provided, the element will be used. To disable the map logo, set the option to false. By default, the OpenLayers logo is shown.
moveTolerance number | undefined

The minimum distance in pixels the cursor must move to be detected as a map move event instead of a click. Increasing this value can make it easier to click on the map. Default is 1.
overlays ol.Collection.<ol.Overlay> | Array.<ol.Overlay> | undefined

Overlays initially added to the map. By default, no overlays are added.
renderer ol.renderer.Type | Array.<ol.renderer.Type> | undefined

Renderer. By default, Canvas and WebGL renderers are tested for support in that order, and the first supported used. Specify a ol.renderer.Type here to use a specific renderer. Note that the Canvas renderer fully supports vector data, but WebGL can only render Point geometries.
target Element | string | undefined

The container for the map, either the element itself or the id of the element. If not specified at construction time, ol.Map#setTarget must be called for the map to be rendered.
view ol.View | undefined

The map's view. No layer sources will be fetched unless this is specified at construction time or through ol.Map#setView.
Fires:

Extends

Observable Properties

Name Type Settable ol.Object.Event type Description
layerGroup ol.layer.Group yes change:layergroup

A layer group containing the layers in this map.
size ol.Size | undefined yes change:size

The size in pixels of the map in the DOM.
target Element | string | undefined yes change:target

The Element or id of the Element that the map is rendered in.
view ol.View yes change:view

The view that controls this map.

Methods

addControl(control) inherited

src/ol/pluggablemap.js, line 373

Add the given control to the map.

Name Type Description
control ol.control.Control

Control.

addInteraction(interaction) inherited

src/ol/pluggablemap.js, line 383

Add the given interaction to the map.

Name Type Description
interaction ol.interaction.Interaction

Interaction to add.

addLayer(layer) inherited

src/ol/pluggablemap.js, line 395

Adds the given layer to the top of this map. If you want to add a layer elsewhere in the stack, use getLayers() and the methods available on ol.Collection.

Name Type Description
layer ol.layer.Base

Layer.

addOverlay(overlay) inherited

src/ol/pluggablemap.js, line 406

Add the given overlay to the map.

Name Type Description
overlay ol.Overlay

Overlay.

changed() inherited

src/ol/observable.js, line 58

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

dispatchEvent(event) inherited

src/ol/observable.js, line 75

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 Object | ol.events.Event | string

Event object.

forEachFeatureAtPixel(pixel, callback, opt_options){T|undefined} inherited

src/ol/pluggablemap.js, line 468

Detect features that intersect a pixel on the viewport, and execute a callback with each intersecting feature. Layers included in the detection can be configured through the layerFilter option in opt_options.

Name Type Description
pixel ol.Pixel

Pixel.
callback function

Feature callback. The callback will be called with two arguments. The first argument is one feature or render feature at the pixel, the second is the layer of the feature and will be null for unmanaged layers. To stop detection, callback functions can return a truthy value.
options

Optional options.

Name Type Description
layerFilter function | undefined

Layer filter function. The filter function will receive one argument, the layer-candidate and it should return a boolean value. Only layers which are visible and for which this function returns true will be tested for features. By default, all visible layers will be tested.
hitTolerance number | undefined

Hit-detection tolerance in pixels. Pixels inside the radius around the given position will be checked for features. This only works for the canvas renderer and not for WebGL. Default is 0.
Returns:
Callback result, i.e. the return value of last callback execution, or the first truthy callback return value.

forEachLayerAtPixel(pixel, callback, opt_this, opt_layerFilter, opt_this2){T|undefined} inherited

src/ol/pluggablemap.js, line 527

Detect layers that have a color value at a pixel on the viewport, and execute a callback with each matching layer. Layers included in the detection can be configured through opt_layerFilter.

Name Type Description
pixel ol.Pixel

Pixel.
callback function

Layer callback. This callback will receive two arguments: first is the layer, second argument is an array representing [R, G, B, A] pixel values (0 - 255) and will be null for layer types that do not currently support this argument. To stop detection, callback functions can return a truthy value.
this S

Value to use as this when executing callback.
layerFilter function

Layer filter function. The filter function will receive one argument, the layer-candidate and it should return a boolean value. Only layers which are visible and for which this function returns true will be tested for features. By default, all visible layers will be tested.
this2 U

Value to use as this when executing layerFilter.
Returns:
Callback result, i.e. the return value of last callback execution, or the first truthy callback return value.

get(key){*} inherited

src/ol/object.js, line 101

Gets a value.

Name Type Description
key string

Key name.
Returns:
Value.

getControls(){ol.Collection.<ol.control.Control>} inherited

src/ol/pluggablemap.js, line 649

Get the map controls. Modifying this collection changes the controls associated with the map.

Returns:
Controls.

getCoordinateFromPixel(pixel){ol.Coordinate} inherited

src/ol/pluggablemap.js, line 633

Get the coordinate for a given pixel. This returns a coordinate in the map view projection.

Name Type Description
pixel ol.Pixel

Pixel position in the map viewport.
Returns:
The coordinate for the pixel position.

getEventCoordinate(event){ol.Coordinate} inherited

src/ol/pluggablemap.js, line 571

Returns the coordinate in view projection for a browser event.

Name Type Description
event Event

Event.
Returns:
Coordinate.

getEventPixel(event){ol.Pixel} inherited

src/ol/pluggablemap.js, line 582

Returns the map pixel position for a browser event relative to the viewport.

Name Type Description
event Event

Event.
Returns:
Pixel.

getFeaturesAtPixel(pixel, opt_options){Array.<(ol.Feature|ol.render.Feature)>} inherited

src/ol/pluggablemap.js, line 492

Get all features that intersect a pixel on the viewport.

Name Type Description
pixel ol.Pixel

Pixel.
options

Optional options.

Name Type Description
layerFilter function | undefined

Layer filter function. The filter function will receive one argument, the layer-candidate and it should return a boolean value. Only layers which are visible and for which this function returns true will be tested for features. By default, all visible layers will be tested.
hitTolerance number | undefined

Hit-detection tolerance in pixels. Pixels inside the radius around the given position will be checked for features. This only works for the canvas renderer and not for WebGL. Default is 0.
Returns:
The detected features or null if none were found.

getInteractions(){ol.Collection.<ol.interaction.Interaction>} inherited

src/ol/pluggablemap.js, line 687

Get the map interactions. Modifying this collection changes the interactions associated with the map.

Interactions are used for e.g. pan, zoom and rotate.

Returns:
Interactions.

getKeys(){Array.<string>} inherited

src/ol/object.js, line 115

Get a list of object property names.

Returns:
List of property names.

getLayerGroup(){ol.layer.Group} inherited

src/ol/pluggablemap.js, line 698

Get the layergroup associated with this map.

Returns:
A layer group containing the layers in this map.

getLayers(){ol.Collection.<ol.layer.Base>} inherited

src/ol/pluggablemap.js, line 708

Get the collection of layers associated with this map.

Returns:
Layers.

getOverlayById(id){ol.Overlay} inherited

src/ol/pluggablemap.js, line 673

Get an overlay by its identifier (the value returned by overlay.getId()). Note that the index treats string and numeric identifiers as the same. So map.getOverlayById(2) will return an overlay with id '2' or 2.

Name Type Description
id string | number

Overlay identifier.
Returns:
Overlay.

getOverlays(){ol.Collection.<ol.Overlay>} inherited

src/ol/pluggablemap.js, line 660

Get the map overlays. Modifying this collection changes the overlays associated with the map.

Returns:
Overlays.

getPixelFromCoordinate(coordinate){ol.Pixel} inherited

src/ol/pluggablemap.js, line 721

Get the pixel for a coordinate. This takes a coordinate in the map view projection and returns the corresponding pixel.

Name Type Description
coordinate ol.Coordinate

A map coordinate.
Returns:
A pixel position in the map viewport.

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

src/ol/object.js, line 125

Get an object of all property names and values.

Returns:
Object.

getRevision(){number} inherited

src/ol/observable.js, line 84

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

Returns:
Revision.

getSize(){ol.Size|undefined} inherited

src/ol/pluggablemap.js, line 747

Get the size of this map.

Returns:
The size in pixels of the map in the DOM.

getTarget(){Element|string|undefined} inherited

src/ol/pluggablemap.js, line 601

Get the target in which this map is rendered. Note that this returns what is entered as an option or in setTarget: if that was an element, it returns an element; if a string, it returns that.

Returns:
The Element or id of the Element that the map is rendered in.

getTargetElement(){Element} inherited

src/ol/pluggablemap.js, line 614

Get the DOM element into which this map is rendered. In contrast to getTarget this method always return an Element, or null if the map has no target.

Returns:
The element that the map is rendered in.

getView(){ol.View} inherited

src/ol/pluggablemap.js, line 759

Get the view associated with this map. A view manages properties such as center and resolution.

Returns:
The view that controls this map.

getViewport(){Element} inherited

src/ol/pluggablemap.js, line 769

Get the element that serves as the map viewport.

Returns:
Viewport.

hasFeatureAtPixel(pixel, opt_options){boolean} inherited

src/ol/pluggablemap.js, line 550

Detect if features intersect a pixel on the viewport. Layers included in the detection can be configured through opt_layerFilter.

Name Type Description
pixel ol.Pixel

Pixel.
options

Optional options.

Name Type Description
layerFilter function | undefined

Layer filter function. The filter function will receive one argument, the layer-candidate and it should return a boolean value. Only layers which are visible and for which this function returns true will be tested for features. By default, all visible layers will be tested.
hitTolerance number | undefined

Hit-detection tolerance in pixels. Pixels inside the radius around the given position will be checked for features. This only works for the canvas renderer and not for WebGL. Default is 0.
Returns:
Is there a feature at the given pixel?

on(type, listener, opt_this){ol.EventsKey|Array.<ol.EventsKey>} inherited

src/ol/observable.js, line 99

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. If called with an array of event types as the first argument, the return will be an array of keys.

once(type, listener, opt_this){ol.EventsKey|Array.<ol.EventsKey>} inherited

src/ol/observable.js, line 124

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. If called with an array of event types as the first argument, the return will be an array of keys.

removeControl(control){ol.control.Control|undefined} inherited

src/ol/pluggablemap.js, line 1079

Remove the given control from the map.

Name Type Description
control ol.control.Control

Control.
Returns:
The removed control (or undefined if the control was not found).

removeInteraction(interaction){ol.interaction.Interaction|undefined} inherited

src/ol/pluggablemap.js, line 1091

Remove the given interaction from the map.

Name Type Description
interaction ol.interaction.Interaction

Interaction to remove.
Returns:
The removed interaction (or undefined if the interaction was not found).

removeLayer(layer){ol.layer.Base|undefined} inherited

src/ol/pluggablemap.js, line 1103

Removes the given layer from the map.

Name Type Description
layer ol.layer.Base

Layer.
Returns:
The removed layer (or undefined if the layer was not found).

removeOverlay(overlay){ol.Overlay|undefined} inherited

src/ol/pluggablemap.js, line 1116

Remove the given overlay from the map.

Name Type Description
overlay ol.Overlay

Overlay.
Returns:
The removed overlay (or undefined if the overlay was not found).

render() inherited

src/ol/pluggablemap.js, line 1064

Request a map rendering (at the next animation frame).

renderSync() inherited

src/ol/pluggablemap.js, line 1052

Requests an immediate render in a synchronous manner.

set(key, value, opt_silent) inherited

src/ol/object.js, line 150

Sets a value.

Name Type Description
key string

Key name.
value *

Value.
silent boolean

Update without triggering an event.

setLayerGroup(layerGroup) inherited

src/ol/pluggablemap.js, line 1222

Sets the layergroup of this map.

Name Type Description
layerGroup ol.layer.Group

A layer group containing the layers in this map.

setProperties(values, opt_silent) inherited

src/ol/object.js, line 170

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.

setSize(size) inherited

src/ol/pluggablemap.js, line 1233

Set the size of this map.

Name Type Description
size ol.Size | undefined

The size in pixels of the map in the DOM.

setTarget(target) inherited

src/ol/pluggablemap.js, line 1245

Set the target element to render this map into.

Name Type Description
target Element | string | undefined

The Element or id of the Element that the map is rendered in.

setView(view) inherited

src/ol/pluggablemap.js, line 1256

Set the view for this map.

Name Type Description
view ol.View

The view that controls this map.

un(type, listener, opt_this) inherited

src/ol/observable.js, line 147

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.

unset(key, opt_silent) inherited

src/ol/object.js, line 184

Unsets a property.

Name Type Description
key string

Key name.
silent boolean

Unset without triggering an event.

updateSize() inherited

src/ol/pluggablemap.js, line 1276

Force a recalculation of the map viewport size. This should be called when third-party code changes the size of the map viewport.