org.geotools.mbstyle.sprite

Class SpriteGraphicFactory

Object

SpriteGraphicFactory

All Implemented Interfaces:

ExternalGraphicFactory, GraphicCache

public class SpriteGraphicFactory
extends Object
implements ExternalGraphicFactory, GraphicCache

Implementation of an ExternalGraphicFactory that takes the address of a Mapbox-style sprite sheet resource and an icon name, and retrieves the icon from the sprite sheet.

Note that this factory expects the MBStyleTransformer to produce ExternalGraphic instances with slightly modified URLs using one of the following forms: {baseUrl}#{iconName} {baseUrl}#icon={iconName}&size={sizeMultiplier}

Only the baseUrl is used to retrieve the sprite sheet (at {baseUrl}.png) and sprite index (at {baseUrl}.json). The iconName (required) is then used by this factory to select the correct icon from the spritesheet, and the size (optional) is used to scale the icon. For example, for the following style:

 {
  "version": 8,
  "name": "A Style",
  "sprite": "file:/GeoServerDataDirs/release/styles/testSpritesheet",
  "glyphs": "...",
  "sources": {...},
  "layers": [...]
 }
 

If a layer in this style references an icon in the spritesheet, e.g. iconName, then the constructed URL for the external graphic should be file:/GeoServerDataDirs/release/styles/testSpritesheet#iconName

See Also:

https://www.mapbox.com/mapbox-gl-js/style-spec/#sprite

Field Summary

Fields

Modifier and Type	Field and Description
static String	FORMAT ExternalGraphic instances with this format will be handled by the SpriteGraphicFactory.
protected static Map<URL,BufferedImage>	imageCache
protected static Map<URL,SpriteIndex>	indexCache

Constructor Summary

Constructors

Constructor and Description
SpriteGraphicFactory()

Method Summary

Modifier and Type	Method and Description
void	clearCache() Images are cached by this factory.
protected HTTPClient	getHttpClient()
Icon	getIcon(Feature feature, Expression url, String format, int size) Turns the specified URL into an Icon, eventually using the Feature attributes to evaluate CQL expressions embedded in the url.
protected SpriteIndex	getSpriteIndex(URL baseUrl) Retrieve the sprite sheet index for the provided sprite base url.
protected static URL	parseBaseUrl(URL loc) Return the base URL (without an appended icon name) from the provided URL.
protected static Map<String,String>	parseFragmentParams(URL url) Parse the parameters from the URL fragment in the provided URL (interpreting the fragment like a query string).
protected static String	parseIconName(URL url) Parse the icon name from the provided URL.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

FORMAT

public static final String FORMAT

ExternalGraphic instances with this format will be handled by the SpriteGraphicFactory.

See Also:

Constant Field Values

imageCache

protected static final Map<URL,BufferedImage> imageCache

indexCache

protected static final Map<URL,SpriteIndex> indexCache

Constructor Detail

SpriteGraphicFactory

public SpriteGraphicFactory()

Method Detail

getIcon

public Icon getIcon(Feature feature,
                    Expression url,
                    String format,
                    int size)
             throws Exception

Description copied from interface: ExternalGraphicFactory

Turns the specified URL into an Icon, eventually using the Feature attributes to evaluate CQL expressions embedded in the url.
The size parameter defines the size of the image (so that vector based symbols can be drawn at the specified size directly), or may be zero or negative if the size was not specified (in that case the "natural" size of the image will be used, which is the size in pixels for raster images, and 16 for any format that does not have a specific size, according to the SLD spec).
null will be returned if this factory cannot handle the provided url.

Specified by:

getIcon in interface ExternalGraphicFactory

Throws:

Exception

parseFragmentParams

protected static Map<String,String> parseFragmentParams(URL url)

Parse the parameters from the URL fragment in the provided URL (interpreting the fragment like a query string). The "name" parameter is required and will cause an MBFormatException if missing. The "size" parameter is optional and defaults to "1".

Returns:

Sprite parameters map providing name, icons, size values.

parseIconName

protected static String parseIconName(URL url)

Parse the icon name from the provided URL. E.g., /path/to/sprite#iconName will return iconName.

Parameters:

url - The url from which to parse the icon name.

Returns:

The icon name.

Throws:

IllegalArgumentException - If the icon name could not be parsed.

parseBaseUrl

protected static URL parseBaseUrl(URL loc)
                           throws MalformedURLException

Return the base URL (without an appended icon name) from the provided URL. /path/to/sprite#iconName will return path/to/sprite

Parameters:

loc - The URL.

Returns:

The URL, without an appended icon name.

Throws:

MalformedURLException

getSpriteIndex

protected SpriteIndex getSpriteIndex(URL baseUrl)
                              throws IOException

Retrieve the sprite sheet index for the provided sprite base url. The base url should have no extension.

Parameters:

baseUrl - The base URL of the Mapbox sprite source (no extension).

Returns:

The sprite sheet index

Throws:

IOException

getHttpClient

protected HTTPClient getHttpClient()

clearCache

public void clearCache()

Images are cached by this factory. This method can be used to drop the cache.

Specified by:

clearCache in interface GraphicCache