ol-mapbox-style

Create OpenLayers maps from Mapbox Style Specification objects.

Getting started

Get an impression of what this library does by exploring the live examples.

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To use the library in an application with an npm based dev environment, install it with

npm install @edc-dev/ol-mapbox-style

When installed this way, just import the ol-mapbox-style module, like in the usage example below. To use a standalone build of ol-mapbox-style, just include 'dist/olms.js' on your HTML page, and access the exported functions from the global olms object (e.g. olms.apply(), olms.applyBackground()). Note that the standalone build depends on the full build of OpenLayers.

ol-mapbox-style v9 requires OpenLayers version >= 7 < 8.

ol-mapbox-style v8 requires OpenLayers version >= 6.13.0 < 7.

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See the API section for the full documentation.

The code below creates an OpenLayers map from Mapbox's Bright v9 style, using a https:// url:

``js
import { apply } from 'ol-mapbox-style';

apply('map', 'https://api.mapbox.com/styles/v1/mapbox/bright-v9?access_token=YOUR_MAPBOX_TOKEN');
`

To assign style and source to a layer only, use applyStyle(). mapbox:// urls are also supported:

`js
import {applyStyle} from 'ol-mapbox-style';
import VectorTileLayer from 'ol/layer/VectorTile.js'

const layer = new VectorTileLayer({declutter: true});
applyStyle(layer, 'mapbox://styles/mapbox/bright-v9', {accessToken: 'YOUR_MAPBOX_TOKEN'});
`

To apply the properties of the Mapbox Style's background layer to the map or a VectorTile layer, use the applyBackground() function.

There is also a low-level API available. To create a style function for individual OpenLayers vector or vector tile layers, use the stylefunction module:

`js
import {stylefunction} from 'ol-mapbox-style';
import VectorLayer from 'ol/layer/Vector.js';
import VectorSource from 'ol/source/Vector.js';
import GeoJSON from 'ol/format/GeoJSON.js';

const layer = new VectorLayer({
source: new VectorSource({
format: new GeoJSON(),
url: 'data/states.geojson'
})
});

fetch('data/states.json').then(function(response) {
response.json().then(function(glStyle) {
stylefunction(layer, glStyle, 'states');
});
});
`

Note that this low-level API does not create a source for the layer, and extra work is required to set up sprite handling for styles that use icons.

Compatibility notes

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Only commonly available system fonts and Google Fonts will automatically be available for any text-font defined in the Mapbox Style object. It is the responsibility of the application to load other fonts. Because ol-mapbox-style uses system and web fonts instead of PBF/SDF glyphs, the font stack is treated a little different: style and weight are taken from the primary font (i.e. the first one in the font stack). Subsequent fonts in the font stack are only used if the primary font is not available/loaded, and they will be used with the style and weight of the primary font.

Building the library

npm run build

The resulting distribution files will be in the dist/ folder. To see the library in action, navigate to dist/index.html.

To run test locally, run

npm test

For debugging tests in the browser, run

npm run karma

and open a browser on the host and port indicated in the console output (usually ) and click the 'DEBUG' button to go to the debug environment.

![Test Job](https://github.com/openlayers/ol-mapbox-style/actions/workflows/test.yml)

API

@edc-dev/ol-mapbox-style

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#### References

- default

#### Modules

- <internal\\>

#### Functions

- apply
- applyBackground
- applyStyle
- getFeatureState
- getLayer
- getLayers
- getSource
- recordStyleLayer
- renderTransparent
- setFeatureState
- stylefunction

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#### default

Renames and re-exports apply

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#### apply

▸ apply(mapOrGroup, style, options?): Promise<Map \| LayerGroup>

Loads and applies a Mapbox Style object into an OpenLayers Map or LayerGroup.
This includes the map background, the layers, and for Map instances that did not
have a View defined yet also the center and the zoom.

Example:

`js
import apply from 'ol-mapbox-style';

apply('map', 'mapbox://styles/mapbox/bright-v9', {accessToken: 'YOUR_MAPBOX_TOKEN'});
`

The center and zoom will only be set if present in the Mapbox Style document,
and if not already set on the OpenLayers map.

Layers will be added to the OpenLayers map, without affecting any layers that
might already be set on the map.

Layers added by apply() will have two additional properties:

- mapbox-source: The id of the Mapbox Style document's source that the
OpenLayers layer was created from. Usually apply() creates one
OpenLayers layer per Mapbox Style source, unless the layer stack has
layers from different sources in between.
- mapbox-layers: The ids of the Mapbox Style document's layers that are
included in the OpenLayers layer.

This function sets an additional mapbox-style property on the OpenLayers
Map or LayerGroup instance, which holds the Mapbox Style object.

##### Parameters

| Name | Type | Description |
| :----------- | :------------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| mapOrGroup | string \| HTMLElement \| Map \| LayerGroup | Either an existing OpenLayers Map instance, or a HTML element, or the id of a HTML element that will be the target of a new OpenLayers Map, or a layer group. If layer group, styles releated to the map and view will be ignored. |
| style | any | JSON style object or style url pointing to a Mapbox Style object. When using Mapbox APIs, the url is the styleUrl shown in Mapbox Studio's "share" panel. In addition, the accessToken option (see below) must be set. When passed as JSON style object, all OpenLayers layers created by apply() will be immediately available, but they may not have a source yet (i.e. when they are defined by a TileJSON url in the Mapbox Style document). When passed as style url, layers will be added to the map when the Mapbox Style document is loaded and parsed. |
| options | Options | Options. |

##### Returns

Promise<Map \| LayerGroup>

A promise that resolves after all layers have been added to
the OpenLayers Map instance or LayerGroup, their sources set, and their styles applied. The
resolve callback will be called with the OpenLayers Map instance or LayerGroup as
argument.

*

#### applyBackground

▸ applyBackground(mapOrLayer, glStyle, options?): Promise<any>

Applies properties of the Mapbox Style's first background layer to the
provided map or VectorTile layer.

Example:

`js
import {applyBackground} from 'ol-mapbox-style';
import {Map} from 'ol';

const map = new Map({target: 'map'});
applyBackground(map, 'https://api.maptiler.com/maps/basic/style.json?key=YOUR_OPENMAPTILES_TOKEN');
`

##### Parameters

| Name | Type | Description |
| :----------- | :----------------------------------------- | :---------------------------------- |
| mapOrLayer | VectorTileLayer \| Map | OpenLayers Map or VectorTile layer. |
| glStyle | any | Mapbox Style object or url. |
| options | Options | Options. |

##### Returns

Promise<any>

Promise that resolves when the background is applied.

*

#### applyStyle

▸ applyStyle(layer, glStyle, sourceOrLayersOrOptions?, optionsOrPath?, resolutions?): Promise<any>

Applies a style function to an ol/layer/VectorTile or ol/layer/Vector
with an ol/source/VectorTile or an ol/source/Vector. If the layer does not have a source
yet, it will be created and populated from the information in the glStyle.

Example:

`js
import {applyStyle} from 'ol-mapbox-style';
import {VectorTile} from 'ol/layer.js';

const layer = new VectorTile({declutter: true});
applyStyle(layer, 'https://api.maptiler.com/maps/basic/style.json?key=YOUR_OPENMAPTILES_TOKEN');
`

The style function will render all layers from the glStyle object that use the source
of the first layer, the specified source, or a subset of layers from the same source. The
source needs to be a "type": "vector" or "type": "geojson" source.

Two additional properties will be set on the provided layer:

- mapbox-source: The id of the Mapbox Style document's source that the
OpenLayers layer was created from. Usually apply() creates one
OpenLayers layer per Mapbox Style source, unless the layer stack has
layers from different sources in between.
- mapbox-layers: The ids of the Mapbox Style document's layers that are
included in the OpenLayers layer.

##### Parameters

| Name | Type | Default value | Description |
| :------------------------- | :------------------------------------------------------------------------------------------------------------------------------------- | :------------ | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| layer | VectorLayer<any> \| VectorTileLayer | undefined | OpenLayers layer. When the layer has a source configured, it will be modified to use the configuration from the glStyle's source. Options specified on the layer's source will override those from the glStyle's source, except for url, tileUrlFunction and tileGrid (exception: when the source projection is not EPSG:3857). |
| glStyle | any | undefined | Mapbox Style object. |
| sourceOrLayersOrOptions? | string \| string\[] \| Options & ApplyStyleOptions | '' | Options or source key or an array of layer ids from the Mapbox Style object. When a source key is provided, all layers for the specified source will be included in the style function. When layer ids are provided, they must be from layers that use the same source. When not provided or a falsey value, all layers using the first source specified in the glStyle will be rendered. |
| optionsOrPath? | string \| Options | {} | Deprecated. Options. Alternatively the path of the style file (only required when a relative path is used for the "sprite" property of the style). |
| resolutions? | number\[] | undefined | Deprecated. Resolutions for mapping resolution to zoom level. Only needed when working with non-standard tile grids or projections, can also be supplied with options. |

##### Returns

Promise<any>

Promise which will be resolved when the style can be used
for rendering.

*

#### getFeatureState

▸ getFeatureState(mapOrLayer, feature): any

Sets or removes a feature state. The feature state is taken into account for styling,
just like the feature's properties, and can be used e.g. to conditionally render selected
features differently.

##### Parameters

| Name | Type | Description |
| :----------- | :------------------------------------------------------------- | :---------------------------------------- |
| mapOrLayer | VectorLayer<any> \| VectorTileLayer \| Map | Map or layer to set the feature state on. |
| feature | FeatureIdentifier | Feature identifier. |

##### Returns

any

Feature state or null when no feature state is set for the given
feature identifier.

*

#### getLayer

▸ getLayer(map, layerId): Layer<Source, LayerRenderer<any>>

Get the OpenLayers layer instance that contains the provided Mapbox Style
layer. Note that multiple Mapbox Style layers are combined in a single
OpenLayers layer instance when they use the same Mapbox Style source.

##### Parameters

| Name | Type | Description |
| :-------- | :-------------------- | :---------------------------- |
| map | Map \| LayerGroup | OpenLayers Map or LayerGroup. |
| layerId | string | Mapbox Style layer id. |

##### Returns

Layer<Source, LayerRenderer<any>>

OpenLayers layer instance.

*

#### getLayers

▸ getLayers(map, sourceId): Layer<Source, LayerRenderer<any>>\[]

Get the OpenLayers layer instances for the provided Mapbox Style source.

##### Parameters

| Name | Type | Description |
| :--------- | :-------------------- | :---------------------------- |
| map | Map \| LayerGroup | OpenLayers Map or LayerGroup. |
| sourceId | string | Mapbox Style source id. |

##### Returns

Layer<Source, LayerRenderer<any>>\[]

OpenLayers layer instances.

*

#### getSource

▸ getSource(map, sourceId): Source

Get the OpenLayers source instance for the provided Mapbox Style source.

##### Parameters

| Name | Type | Description |
| :--------- | :-------------------- | :---------------------------- |
| map | Map \| LayerGroup | OpenLayers Map or LayerGroup. |
| sourceId | string | Mapbox Style source id. |

##### Returns

Source

OpenLayers source instance.

*

#### recordStyleLayer

▸ recordStyleLayer(record?): void

Turns recording of the Mapbox Style's layer on and off. When turned on,
the layer that a rendered feature belongs to will be set as the feature's
mapbox-layer property.

##### Parameters

| Name | Type | Default value | Description |
| :------- | :-------- | :------------ | :---------------------------------- |
| record | boolean | false | Recording of the style layer is on. |

##### Returns

void

*

#### renderTransparent

▸ renderTransparent(enabled): void

Configure whether features with a transparent style should be rendered. When
set to true, it will be possible to hit detect content that is not visible,
like transparent fills of polygons, using ol/layer/Layer#getFeatures() or
ol/Map#getFeaturesAtPixel()

##### Parameters

| Name | Type | Description |
| :-------- | :-------- | :---------------------------------------------------------------- |
| enabled | boolean | Rendering of transparent elements is enabled. Default is false. |

##### Returns

void

*

#### setFeatureState

▸ setFeatureState(mapOrLayer, feature, state): void

Sets or removes a feature state. The feature state is taken into account for styling,
just like the feature's properties, and can be used e.g. to conditionally render selected
features differently.

The feature state will be stored on the OpenLayers layer matching the feature identifier, in the
mapbox-featurestate property.

##### Parameters

| Name | Type | Description |
| :----------- | :------------------------------------------------------------- | :-------------------------------------------------------- |
| mapOrLayer | VectorLayer<any> \| VectorTileLayer \| Map | OpenLayers Map or layer to set the feature state on. |
| feature | FeatureIdentifier | Feature identifier. |
| state | any | Feature state. Set to null to remove the feature state. |

##### Returns

void

*

#### stylefunction

▸ stylefunction(olLayer, glStyle, sourceOrLayers, resolutions?, spriteData?, spriteImageUrl?, getFonts?, getImage?): StyleFunction

Creates a style function from the glStyle object for all layers that use
the specified source, which needs to be a "type": "vector" or
"type": "geojson" source and applies it to the specified OpenLayers layer.

Two additional properties will be set on the provided layer:

- mapbox-source: The id of the Mapbox Style document's source that the
OpenLayers layer was created from. Usually apply() creates one
OpenLayers layer per Mapbox Style source, unless the layer stack has
layers from different sources in between.
- mapbox-layers: The ids of the Mapbox Style document's layers that are
included in the OpenLayers layer.

This function also works in a web worker. In worker mode, the main thread needs
to listen to messages from the worker and respond with another message to make
sure that sprite image loading works:

`js
worker.addEventListener('message', event => {
if (event.data.action === 'loadImage') {
const image = new Image();
image.crossOrigin = 'anonymous';
image.addEventListener('load', function() {
createImageBitmap(image, 0, 0, image.width, image.height).then(imageBitmap => {
worker.postMessage({
action: 'imageLoaded',
image: imageBitmap,
src: event.data.src
}, [imageBitmap]);
});
});
image.src = event.data.src;
}
});
`

##### Parameters

| Name | Type | Default value | Description |
| :--------------- | :-------------------------------------------------------------------------------------------------------------------------------- | :------------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| olLayer | VectorLayer<any> \| VectorTileLayer | undefined | OpenLayers layer to apply the style to. In addition to the style, the layer will get two properties: mapbox-source will be the id of the glStyle's source used for the layer, and mapbox-layers will be an array of the ids of the glStyle's layers. |
| glStyle | any | undefined | Mapbox Style object. |
| sourceOrLayers | string \| string\[] | undefined | source key or an array of layer ids from the Mapbox Style object. When a source key is provided, all layers for the specified source will be included in the style function. When layer ids are provided, they must be from layers that use the same source. |
| resolutions | number\[] | defaultResolutions | Resolutions for mapping resolution to zoom level. |
| spriteData | any | undefined | Sprite data from the url specified in the Mapbox Style object's sprite property. Only required if a sprite property is specified in the Mapbox Style object. |
| spriteImageUrl | string | undefined | Sprite image url for the sprite specified in the Mapbox Style object's sprite property. Only required if a sprite property is specified in the Mapbox Style object. |
| getFonts | (arg0: string\[]) => string\[] | undefined | Function that receives a font stack as arguments, and returns a (modified) font stack that is available. Font names are the names used in the Mapbox Style object. If not provided, the font stack will be used as-is. This function can also be used for loading web fonts. |
| getImage? | (arg0: VectorLayer<any> \| VectorTileLayer, arg1: string) => string \| HTMLCanvasElement \| HTMLImageElement | undefined | Function that returns an image or a URL for an image name. If the result is an HTMLImageElement, it must already be loaded. The layer can be used to call layer.changed() when the loading and processing of the image has finished. This function can be used for icons not in the sprite or to override sprite icons. |

##### Returns

StyleFunction

Style function for use in
ol.layer.Vector or ol.layer.VectorTile.

Interface: ApplyStyleOptions<>

.ApplyStyleOptions

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#### Properties

- layers
- source

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#### layers

• layers: string\[]

Layers. If no source is provided, the layers with the
provided ids will be used from the style's layers array. All layers need to use the same source.

*

#### source

• source: string

Source. Default is '', which causes the first source in the
style to be used.

Interface: FeatureIdentifier<>

.FeatureIdentifier

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#### Properties

- id
- source

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#### id

• id: string \| number

The feature id.

*

#### source

• source: string

The source id.

Interface: Options<>

.Options

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#### Properties

- accessToken
- accessTokenParam
- getImage
- resolutions
- styleUrl
- transformRequest

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#### accessToken

• accessToken: string

Access token for 'mapbox://' urls.

*

#### accessTokenParam

• accessTokenParam: string

Access token param. For internal use.

*

#### getImage

• getImage: (arg0: VectorLayer<any> \| VectorTileLayer, arg1: string) => string \| HTMLCanvasElement \| HTMLImageElement

##### Type declaration

▸ (arg0, arg1): string \| HTMLCanvasElement \| HTMLImageElement

Function that returns an image for an icon name. If the result is an HTMLImageElement, it must already be
loaded. The layer can be used to call layer.changed() when the loading and processing of the image has finished.
This function be used for icons not in the sprite or to override sprite icons.

###### Parameters

| Name | Type |
| :----- | :------------------------------------------- |
| arg0 | VectorLayer<any> \| VectorTileLayer |
| arg1 | string |

###### Returns

string \| HTMLCanvasElement \| HTMLImageElement

*

#### resolutions

• resolutions: number\[]

Resolutions for mapping resolution to zoom level.
Only needed when working with non-standard tile grids or projections.

*

#### styleUrl

• styleUrl: string

URL of the Mapbox GL style. Required for styles that were provided
as object, when they contain a relative sprite url, or sources referencing data by relative url.

*

#### transformRequest

• transformRequest: (arg0: string, arg1: ResourceType) => void \| Request

##### Type declaration

▸ (arg0, arg1): void \| Request

Function for controlling how ol-mapbox-style fetches resources. Can be used for modifying
the url, adding headers or setting credentials options. Called with the url and the resource
type as arguments, this function is supposed to return a Request object. Without a return value,
the original request will not be modified. For Tiles and GeoJSON resources, only the url of
the returned request will be respected.

###### Parameters

| Name | Type |
| :----- | :------------------------------ |
| arg0 | string |
| arg1 | ResourceType |

###### Returns

void \| Request

Module: <internal>

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#### Interfaces

- ApplyStyleOptions
- FeatureIdentifier
- Options

#### Type Aliases

- ResourceType

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#### ResourceType

Ƭ ResourceType<>: "Style" \| "Source" \| "Sprite" \| "SpriteImage" \| "Tiles" \| "GeoJSON"`