ImageCanvas~ImageCanvasSource

import ImageCanvasSource from 'ol/source/ImageCanvas.js';

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

new ImageCanvasSource(options) source/ImageCanvas.js, line 54

Name	Type	Description
`attributions`	AttributionLike \| undefined	Attributions.
`canvasFunction`	FunctionType \| undefined	Canvas function. The function returning the canvas element used by the source as an image. The arguments passed to the function are: `Extent` the image extent, `{number}` the image resolution, `{number}` the pixel ratio of the map, `Size` the image size, and `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 `changed` should be called on the source for the source to invalidate the current cached image. See: `changed`
`interpolate`	boolean (defaults to true)	Use interpolated values when resampling. By default, linear interpolation is used when resampling. Set to false to use the nearest neighbor instead.
`projection`	ProjectionLike \| undefined	Projection. Default is the view projection.
`ratio`	number (defaults to 1.5)	Ratio. 1 means canvases are the size of the map viewport, 2 means twice the width and height of the map viewport, and so on. Must be `1` or higher.
`resolutions`	Array.<number> \| undefined	Resolutions. If specified, new canvases will be created for these resolutions
`state`	State \| undefined	Source state.

Fires:

change (BaseEvent) - Generic change event. Triggered when the revision counter is increased.
error (BaseEvent) - Generic error event. Triggered when an error occurs.
imageloadend (ImageSourceEvent) - Triggered when an image finishes loading.
imageloaderror (ImageSourceEvent) - Triggered if image loading results in an error.
imageloadstart (ImageSourceEvent) - Triggered when an image starts loading.
propertychange (ObjectEvent) - Triggered when a property is changed.

Extends

ImageSource

Methods

changed() inherited Observable.js, line 68

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`	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 136

Gets a value.

Name	Type	Description
`key`	string	Key name.

Returns:

Value.

getAttributions(){Attribution} inherited source/Source.js, line 129

Get the attribution function for the source.

Returns:

Attribution function.

getAttributionsCollapsible(){boolean} inherited source/Source.js, line 137

Returns:

Attributions are collapsible.

getKeys(){Array.<string>} inherited Object.js, line 149

Get a list of object property names.

Returns:

List of property names.

getProjection(){Projection | null} inherited source/Source.js, line 146

Get the projection of the source.

Returns:

Projection.

getProperties(){NoInfer.<Properties>} inherited Object.js, line 158

Get an object of all property names and values.

Returns:

Object.

getRevision(){number} inherited Observable.js, line 79

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

Returns:

Revision.

getState(){State} inherited source/Source.js, line 201

Get the state of the source, see State for possible states.

Returns:

State.

on(type, listener){EventsKey | Array<EventsKey>} inherited Observable.js, line 152

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){EventsKey | Array<EventsKey>} inherited Observable.js, line 164

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.

refresh() inherited source/Source.js, line 223

Refreshes the source. The source will be cleared, and data from the server will be reloaded.

set(key, value, silent) inherited Object.js, line 218

Sets a value.

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

setAttributions(attributions) inherited source/Source.js, line 234

Set the attributions of the source.

Name	Type	Description
`attributions`	AttributionLike \| undefined	Attributions. Can be passed as `string`, `Array<string>`, `Attribution`, or `undefined`.

setProperties(values, silent) inherited Object.js, line 238

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`	Partial.<NoInfer.<Properties>>	Values.
`silent`	boolean \| undefined	Update without triggering an event.

un(type, listener) inherited Observable.js, line 173

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, silent) inherited Object.js, line 262

Unsets a property.

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