OpenLayers 3 API Documentation

Class: ImageCanvas

ol.source.ImageCanvas

Base class for image sources where a canvas element is the image.

new ol.source.ImageCanvas(options) experimental

src/ol/source/imagecanvassource.js, line 19
Name Type Description
options
Name Type Description
attributions Array.<ol.Attribution> | undefined optional

Attributions.
canvasFunction ol.CanvasFunctionType

Canvas function. The function returning the canvas element used by the source as an image. The arguments passed to the function are: {ol.Extent} the image extent, {number} the image resolution, {number} the device pixel ratio, {ol.Size} the image size, and {ol.proj.Projection} the image projection. The canvas returned by this function is cached by the source. If the value returned by the function is later changed then dispatchChangeEvent should be called on the source for the source to invalidate the current cached image.
extent ol.Extent | undefined optional

Extent.
logo string | undefined optional

Logo.
projection ol.proj.ProjectionLike

Projection.
ratio number | undefined optional

Ratio. 1 means canvases are the size of the map viewport, 2 means twice the size of the map viewport, and so on. Default is 1.5.
resolutions Array.<number> | undefined optional

Resolutions. If specified, new canvases will be created for these resolutions only.
state ol.source.State | string | undefined optional

Source state.
Fires:
  • change experimental - Triggered when the state of the source changes.

Subclasses

Extends

Methods

dispatchChangeEvent() inherited experimental

src/ol/observable.js, line 41

Dispatches a change event.

Fires:
  • change experimental

getState(){ol.source.State} inherited experimental

src/ol/source/source.js, line 142
Returns:
State.

on(type, listener, opt_this){goog.events.Key} inherited experimental

src/ol/observable.js, line 63

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 optional

The object to use as this in listener.
Returns:
Unique key for the listener.

once(type, listener, opt_this){goog.events.Key} inherited experimental

src/ol/observable.js, line 76

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 optional

The object to use as this in listener.
Returns:
Unique key for the listener.

un(type, listener, opt_this) inherited experimental

src/ol/observable.js, line 88

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 optional

The object to use as this in listener.

unByKey(key) inherited experimental

src/ol/observable.js, line 98

Removes an event listener using the key returned by on() or once().

Name Type Description
key goog.events.Key

Key.