151 lines
6.9 KiB
Objective-C
151 lines
6.9 KiB
Objective-C
#import "MGLFeature.h"
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#import "MGLFoundation.h"
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#import "MGLTileSource.h"
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NS_ASSUME_NONNULL_BEGIN
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/**
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`MGLVectorTileSource` is a map content source that supplies tiled vector data
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in <a href="https://www.mapbox.com/vector-tiles/">Mapbox Vector Tile</a> format
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to be shown on the map. The location of and metadata about the tiles are
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defined either by an option dictionary or by an external file that conforms to
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the
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<a href="https://github.com/mapbox/tilejson-spec/">TileJSON specification</a>.
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A vector tile source is added to an `MGLStyle` object along with one or more
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`MGLVectorStyleLayer` objects. A vector style layer defines the appearance of
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any content supplied by the vector tile source.
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`MGLVectorTileSource` is optimized for data sets that are too large to fit
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completely in memory, such as vector tile sets or data sets managed in
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<a href="https://www.mapbox.com/studio/">Mapbox Studio</a>. For
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<a href="http://geojson.org/">GeoJSON</a> data, use the `MGLShapeSource`
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class. For tiled data that changes dynamically, the `MGLComputedShapeSource`
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class may be a suitable alternative.
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Each
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<a href="https://www.mapbox.com/mapbox-gl-style-spec/#sources-vector"><code>vector</code></a>
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source defined by the style JSON file is represented at runtime by an
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`MGLVectorTileSource` object that you can use to initialize new style layers.
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You can also add and remove sources dynamically using methods such as
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`-[MGLStyle addSource:]` and `-[MGLStyle sourceWithIdentifier:]`.
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Within each vector tile, each geometric coordinate must lie between
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−1 × <var>extent</var> and
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(<var>extent</var> × 2) − 1, inclusive. Any vector style
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layer initialized with a vector tile source must have a non-`nil` value in its
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`sourceLayerIdentifier` property.
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Commonly used vector tile sources include
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<a href="https://www.mapbox.com/vector-tiles/mapbox-streets/">Mapbox Streets</a>,
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<a href="https://www.mapbox.com/vector-tiles/mapbox-terrain/">Mapbox Terrain</a>,
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and
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<a href="https://www.mapbox.com/vector-tiles/mapbox-traffic-v1/">Mapbox Traffic</a>.
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### Example
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```swift
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let source = MGLVectorTileSource(identifier: "pois", tileURLTemplates: ["https://example.com/vector-tiles/{z}/{x}/{y}.mvt"], options: [
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.minimumZoomLevel: 9,
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.maximumZoomLevel: 16,
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.attributionInfos: [
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MGLAttributionInfo(title: NSAttributedString(string: "© Mapbox"), url: URL(string: "https://mapbox.com"))
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]
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])
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mapView.style?.addSource(source)
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```
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#### Related examples
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See the <a href="https://docs.mapbox.com/ios/maps/examples/dds-circle-layer/">
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Data-driven circles</a> example to learn how to add data to your map using
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an `MGLVectorTileSource` object.
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*/
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MGL_EXPORT
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@interface MGLVectorTileSource : MGLTileSource
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#pragma mark Initializing a Source
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/**
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Returns a vector tile source initialized with an identifier and configuration
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URL.
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After initializing and configuring the source, add it to a map view’s style
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using the `-[MGLStyle addSource:]` method.
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The URL may be a full HTTP or HTTPS URL or, for tile sets hosted by Mapbox, a
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Mapbox URL indicating a map identifier (`mapbox://<mapid>`). The URL should
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point to a JSON file that conforms to the
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<a href="https://github.com/mapbox/tilejson-spec/">TileJSON specification</a>.
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@param identifier A string that uniquely identifies the source in the style to
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which it is added.
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@param configurationURL A URL to a TileJSON configuration file describing the
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source’s contents and other metadata.
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@return An initialized vector tile source.
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*/
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- (instancetype)initWithIdentifier:(NSString *)identifier configurationURL:(NSURL *)configurationURL NS_DESIGNATED_INITIALIZER;
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/**
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Returns a vector tile source initialized an identifier, tile URL templates, and
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options.
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Tile URL templates are strings that specify the URLs of the vector tiles to
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load. See the “<a href="../tile-url-templates.html">Tile URL Templates</a>”
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guide for information about the format of a tile URL template.
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After initializing and configuring the source, add it to a map view’s style
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using the `-[MGLStyle addSource:]` method.
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@param identifier A string that uniquely identifies the source in the style to
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which it is added.
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@param tileURLTemplates An array of tile URL template strings. Only the first
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string is used; any additional strings are ignored.
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@param options A dictionary containing configuration options. See
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`MGLTileSourceOption` for available keys and values. Pass in `nil` to use
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the default values.
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@return An initialized tile source.
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*/
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- (instancetype)initWithIdentifier:(NSString *)identifier tileURLTemplates:(NSArray<NSString *> *)tileURLTemplates options:(nullable NSDictionary<MGLTileSourceOption, id> *)options NS_DESIGNATED_INITIALIZER;
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#pragma mark Accessing a Source’s Content
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/**
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Returns an array of map features loaded by this source, restricted to the given
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source layers and filtered by the given predicate.
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Each object in the returned array represents a feature loaded by the source and
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provides access to attributes specified as part of the loaded feature. The
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source loads a feature if the source is added to an `MGLMapView`’s style; that
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style has a layer that uses the source; and the map view has recently scrolled
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to the region containing the feature.
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Features come from tiled vector data that is converted to tiles internally, so
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feature geometries are clipped at tile boundaries and features may appear
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duplicated across tiles. For example, suppose part of a lengthy polyline
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representing a road has recently scrolled into view. The resulting array
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includes those parts of the road that lie within the map tiles that the source
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has loaded, even if the road extends into other tiles. The portion of the road
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within each map tile is included individually.
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Returned features may not necessarily be visible to the user at the time they
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are loaded: the style may contain a layer that forces the source’s tiles to
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load but filters out the features in question, preventing them from being
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drawn. To obtain only _visible_ features, use the
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`-[MGLMapView visibleFeaturesAtPoint:inStyleLayersWithIdentifiers:predicate:]`
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or
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`-[MGLMapView visibleFeaturesInRect:inStyleLayersWithIdentifiers:predicate:]`
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method.
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@param sourceLayerIdentifiers The source layers to include in the query. Only
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the features contained in these source layers are included in the returned
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array. This array may not be empty.
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@param predicate A predicate to filter the returned features. Use `nil` to
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include all loaded features.
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@return An array of objects conforming to the `MGLFeature` protocol that
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represent features loaded by the source that match the predicate.
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*/
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- (NSArray<id <MGLFeature>> *)featuresInSourceLayersWithIdentifiers:(NSSet<NSString *> *)sourceLayerIdentifiers predicate:(nullable NSPredicate *)predicate NS_SWIFT_NAME(features(sourceLayerIdentifiers:predicate:));
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@end
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NS_ASSUME_NONNULL_END
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