[ios, macos] Expose name and default position of current style (#6127)

* [ios] Reset to style’s default position

* [ios, macos] Added name property to MGLStyle

platform/darwin/src/MGLStyle.h

@@ -164,6 +164,13 @@ static const NSInteger MGLStyleDefaultVersion = 9;
  */
 + (NSURL *)satelliteStreetsStyleURLWithVersion:(NSInteger)version;
 
+/**
+ The name of the style.
+ 
+ You can customize the style’s name in Mapbox Studio.
+ */
+@property (readonly, copy, nullable) NSString *name;
+
 #pragma mark Runtime Styling
 
 /**

platform/darwin/src/MGLStyle.mm

@@ -88,6 +88,10 @@ + (NSURL *)emeraldStyleURL {
     return MGLStyleURL_emerald;
 }
 
+- (NSString *)name {
+    return @(self.mapView.mbglMap->getStyleName().c_str());
+}
+
 - (mbgl::style::Layer *)mbglLayerWithIdentifier:(NSString *)identifier
 {
     return self.mapView.mbglMap->getLayer(identifier.UTF8String);

platform/ios/CHANGELOG.md

@@ -17,6 +17,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 * Added [quadkey](https://msdn.microsoft.com/en-us/library/bb259689.aspx) support and limited WMS support in raster tile URL templates. ([#5628](https://github.com/mapbox/mapbox-gl-native/pull/5628))
 * TileJSON manifests can now specify `"scheme": "tms"` to indicate the use of [TMS](https://en.wikipedia.org/wiki/Tile_Map_Service) coordinates. ([#2270](https://github.com/mapbox/mapbox-gl-native/pull/2270))
 * Fixed rendering artifacts and missing glyphs that occurred after viewing a large number of CJK characters on the map. ([#5908](https://github.com/mapbox/mapbox-gl-native/pull/5908))
+* `-[MGLMapView resetPosition]` now resets to the current style’s default center coordinates, zoom level, direction, and pitch, if specified. ([#6127](https://github.com/mapbox/mapbox-gl-native/pull/6127))
 * The `text-pitch-alignment` property is now supported in stylesheets for improved street label legibility on a tilted map. ([#5288](https://github.com/mapbox/mapbox-gl-native/pull/5288))
 * The `icon-text-fit` and `icon-text-fit-padding` properties are now supported in stylesheets, allowing the background of a shield to automatically resize to fit the shield’s text. ([#5334](https://github.com/mapbox/mapbox-gl-native/pull/5334))
 * The `circle-pitch-scale` property is now supported in stylesheets, allowing circle features in a tilted base map to scale or remain the same size as the viewing distance changes. ([#5576](https://github.com/mapbox/mapbox-gl-native/pull/5576))

platform/ios/src/MGLMapView.h

@@ -539,6 +539,14 @@ IB_DESIGNABLE
  */
 - (IBAction)resetNorth;
 
+/**
+ Resets the map to the current style’s default viewport.
+ 
+ If the style doesn’t specify a default viewport, the map resets to a minimum
+ zoom level, a center coordinate of (0, 0), and a northern heading.
+ */
+- (IBAction)resetPosition;
+
 /**
  The coordinate bounds visible in the receiver’s viewport.
  
@@ -1195,12 +1203,6 @@ IB_DESIGNABLE
 
 - (void)emptyMemoryCache __attribute__((deprecated));
 
-/**
-    Resets the map to the minimum zoom level, a center coordinate of (0, 0), and
-    a northern heading.
- */
-- (void)resetPosition;
-
 @end
 
 NS_ASSUME_NONNULL_END

platform/ios/src/MGLMapView.mm

@@ -1899,9 +1899,13 @@ - (void)resetNorthAnimated:(BOOL)animated
 
 - (void)resetPosition
 {
-    MGLMapCamera *camera = [MGLMapCamera camera];
-    camera.altitude = MGLAltitudeForZoomLevel(0, 0, 0, self.frame.size);
-    self.camera = camera;
+    CGFloat pitch = _mbglMap->getDefaultPitch();
+    CLLocationDirection heading = mbgl::util::wrap(_mbglMap->getDefaultBearing(), 0., 360.);
+    CLLocationDistance distance = MGLAltitudeForZoomLevel(_mbglMap->getDefaultZoom(), pitch, 0, self.frame.size);
+    self.camera = [MGLMapCamera cameraLookingAtCenterCoordinate:MGLLocationCoordinate2DFromLatLng(_mbglMap->getDefaultLatLng())
+                                                   fromDistance:distance
+                                                          pitch:pitch
+                                                        heading:heading];
 }
 
 - (void)emptyMemoryCache