[ios,macos] multipolygon coordinate (#8713)

* [ios] MGLMultiPolygon's coordinate property implemented

* [ios,macos] Add polylabalel to project config

* [ios,macos] Change coordinate property for MGLPolyline,MGLPolygon,MGLMultiPolygon

* [macos] Change project configuration to support polilabel

* [ios,macos] Add MGLLocationCoordinate2DFromPoint

* [ios, macos] Update changelogs

* [ios, macos] remove unnecesary variables

* [ios, macos] Add radians conversions

* [ios, macos] Add coordinate calc to MGLPolyline

* [ios, macos] Move radian fuctions to MGLGeometry_Private.h

* [ios, macos] Fix code style

* [ios, macos] Fix code indentation

* [ios, macos] Fix radian per meters constant

* [ios, macos] Add test scenarios to testPolyline

* [ios, macos] Fix test accuracy

1 files changed, 19 insertions, 1 deletions

diff --git a/platform/darwin/src/MGLPolygon.mm b/platform/darwin/src/MGLPolygon.mm
index ceafe873bf..d966ff13ce 100644
--- a/platform/darwin/src/MGLPolygon.mm
+++ b/platform/darwin/src/MGLPolygon.mm
@@ -6,6 +6,7 @@
 #import "MGLPolygon+MGLAdditions.h"
 
 #import <mbgl/util/geojson.hpp>
+#import <mapbox/polylabel.hpp>
 
 @implementation MGLPolygon
 
@@ -54,6 +55,13 @@
     return [super hash] + [[self geoJSONDictionary] hash];
 }
 
+- (CLLocationCoordinate2D)coordinate {
+    // pole of inaccessibility
+    auto poi = mapbox::polylabel([self polygon]);
+    
+    return MGLLocationCoordinate2DFromPoint(poi);
+}
+
 - (mbgl::LinearRing<double>)ring {
     NSUInteger count = self.pointCount;
     CLLocationCoordinate2D *coordinates = self.coordinates;
@@ -155,11 +163,17 @@
     return hash;
 }
 
+- (CLLocationCoordinate2D)coordinate {
+    MGLPolygon *firstPolygon = self.polygons.firstObject;
+    
+    return firstPolygon.coordinate;
+}
+
 - (BOOL)intersectsOverlayBounds:(MGLCoordinateBounds)overlayBounds {
     return MGLCoordinateBoundsIntersectsCoordinateBounds(_overlayBounds, overlayBounds);
 }
 
-- (mbgl::Geometry<double>)geometryObject {
+- (mbgl::MultiPolygon<double>)multiPolygon {
     mbgl::MultiPolygon<double> multiPolygon;
     multiPolygon.reserve(self.polygons.count);
     for (MGLPolygon *polygon in self.polygons) {
@@ -173,6 +187,10 @@
     return multiPolygon;
 }
 
+- (mbgl::Geometry<double>)geometryObject {
+    return [self multiPolygon];
+}
+
 - (NSDictionary *)geoJSONDictionary {
     NSMutableArray *coordinates = [[NSMutableArray alloc] initWithCapacity:self.polygons.count];
     for (MGLPolygonFeature *feature in self.polygons) {