[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

platform/darwin/src/MGLGeometry_Private.h

@@ -8,6 +8,26 @@
 #import <mbgl/util/geo.hpp>
 #import <mbgl/util/geometry.hpp>
 
+typedef double MGLLocationRadians;
+typedef double MGLRadianDistance;
+typedef double MGLRadianDirection;
+
+/** Defines the coordinate by a `MGLRadianCoordinate2D`. */
+typedef struct MGLRadianCoordinate2D {
+    MGLLocationRadians latitude;
+    MGLLocationRadians longitude;
+} MGLRadianCoordinate2D;
+
+/**
+ Creates a new `MGLRadianCoordinate2D` from the given latitudinal and longitudinal.
+ */
+NS_INLINE MGLRadianCoordinate2D MGLRadianCoordinate2DMake(MGLLocationRadians latitude, MGLLocationRadians longitude) {
+    MGLRadianCoordinate2D radianCoordinate;
+    radianCoordinate.latitude = latitude;
+    radianCoordinate.longitude = longitude;
+    return radianCoordinate;
+}
+
 /// Returns the smallest rectangle that contains both the given rectangle and
 /// the given point.
 CGRect MGLExtendRect(CGRect rect, CGPoint point);
@@ -18,6 +38,10 @@ NS_INLINE mbgl::Point<double> MGLPointFromLocationCoordinate2D(CLLocationCoordin
     return mbgl::Point<double>(coordinate.longitude, coordinate.latitude);
 }
 
+NS_INLINE CLLocationCoordinate2D MGLLocationCoordinate2DFromPoint(mbgl::Point<double> point) {
+    return CLLocationCoordinate2DMake(point.y, point.x);
+}
+
 NS_INLINE CLLocationCoordinate2D MGLLocationCoordinate2DFromLatLng(mbgl::LatLng latLng) {
     return CLLocationCoordinate2DMake(latLng.latitude(), latLng.longitude());
 }
@@ -59,3 +83,43 @@ CLLocationDistance MGLAltitudeForZoomLevel(double zoomLevel, CGFloat pitch, CLLo
     @param size The size of the viewport.
     @return A zero-based zoom level. */
 double MGLZoomLevelForAltitude(CLLocationDistance altitude, CGFloat pitch, CLLocationDegrees latitude, CGSize size);
+
+/** Returns MGLRadianCoordinate2D, converted from CLLocationCoordinate2D. */
+NS_INLINE MGLRadianCoordinate2D MGLRadianCoordinateFromLocationCoordinate(CLLocationCoordinate2D locationCoordinate) {
+    return MGLRadianCoordinate2DMake(MGLRadiansFromDegrees(locationCoordinate.latitude),
+                                     MGLRadiansFromDegrees(locationCoordinate.longitude));
+}
+
+/*
+ Returns the distance in radians given two coordinates.
+ */
+NS_INLINE MGLRadianDistance MGLDistanceBetweenRadianCoordinates(MGLRadianCoordinate2D from, MGLRadianCoordinate2D to)
+{
+    double a = pow(sin((to.latitude - from.latitude) / 2), 2)
+                + pow(sin((to.longitude - from.longitude) / 2), 2) * cos(from.latitude) * cos(to.latitude);
+
+    return 2 * atan2(sqrt(a), sqrt(1 - a));
+}
+
+/*
+ Returns direction in radians given two coordinates.
+ */
+NS_INLINE MGLRadianDirection MGLRadianCoordinatesDirection(MGLRadianCoordinate2D from, MGLRadianCoordinate2D to) {
+    double a = sin(to.longitude - from.longitude) * cos(to.latitude);
+    double b = cos(from.latitude) * sin(to.latitude)
+                - sin(from.latitude) * cos(to.latitude) * cos(to.longitude - from.longitude);
+    return atan2(a, b);
+}
+
+/*
+ Returns coordinate at a given distance and direction away from coordinate.
+ */
+NS_INLINE MGLRadianCoordinate2D MGLRadianCoordinateAtDistanceFacingDirection(MGLRadianCoordinate2D coordinate,
+                                                                             MGLRadianDistance distance,
+                                                                             MGLRadianDirection direction) {
+    double otherLatitude = asin(sin(coordinate.latitude) * cos(distance)
+                                + cos(coordinate.latitude) * sin(distance) * cos(direction));
+    double otherLongitude = coordinate.longitude + atan2(sin(direction) * sin(distance) * cos(coordinate.latitude),
+                                                         cos(distance) - sin(coordinate.latitude) * sin(otherLatitude));
+    return MGLRadianCoordinate2DMake(otherLatitude, otherLongitude);
+}

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 @@ - (NSUInteger)hash {
     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 @@ - (NSUInteger)hash {
     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 @@ - (BOOL)intersectsOverlayBounds:(MGLCoordinateBounds)overlayBounds {
     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) {

platform/darwin/src/MGLPolyline.mm

@@ -6,6 +6,7 @@
 #import "MGLPolyline+MGLAdditions.h"
 
 #import <mbgl/util/geojson.hpp>
+#import <mapbox/polylabel.hpp>
 
 @implementation MGLPolyline
 
@@ -52,6 +53,61 @@ - (BOOL)isEqual:(id)other {
     return self == other || ([other isKindOfClass:[MGLPolyline class]] && [super isEqual:other]);
 }
 
+- (CLLocationCoordinate2D)coordinate {
+    NSUInteger count = self.pointCount;
+    NSAssert(count > 0, @"Polyline must have coordinates");
+
+    CLLocationCoordinate2D *coordinates = self.coordinates;
+    CLLocationDistance middle = [self length] / 2.0;
+    CLLocationDistance traveled = 0.0;
+
+    if (count > 1 || middle > traveled) {
+        for (NSUInteger i = 0; i < count; i++) {
+
+            MGLRadianCoordinate2D from = MGLRadianCoordinateFromLocationCoordinate(coordinates[i]);
+            MGLRadianCoordinate2D to = MGLRadianCoordinateFromLocationCoordinate(coordinates[i + 1]);
+
+            if (traveled >= middle) {
+                double overshoot = middle - traveled;
+                if (overshoot == 0) {
+                    return coordinates[i];
+                }
+                to = MGLRadianCoordinateFromLocationCoordinate(coordinates[i - 1]);
+                CLLocationDirection direction = [self direction:from to:to] - 180;
+                MGLRadianCoordinate2D otherCoordinate = MGLRadianCoordinateAtDistanceFacingDirection(from,
+                                                                                                     overshoot/mbgl::util::EARTH_RADIUS_M,
+                                                                                                     MGLRadiansFromDegrees(direction));
+                return CLLocationCoordinate2DMake(MGLDegreesFromRadians(otherCoordinate.latitude),
+                                                  MGLDegreesFromRadians(otherCoordinate.longitude));
+            }
+
+            traveled += (MGLDistanceBetweenRadianCoordinates(from, to) * mbgl::util::EARTH_RADIUS_M);
+
+        }
+    }
+
+    return coordinates[count - 1];
+}
+
+- (CLLocationDistance)length
+{
+    CLLocationDistance length = 0.0;
+
+    NSUInteger count = self.pointCount;
+    CLLocationCoordinate2D *coordinates = self.coordinates;
+
+    for (NSUInteger i = 0; i < count - 1; i++) {        
+        length += (MGLDistanceBetweenRadianCoordinates(MGLRadianCoordinateFromLocationCoordinate(coordinates[i]),                                                  MGLRadianCoordinateFromLocationCoordinate(coordinates[i + 1])) * mbgl::util::EARTH_RADIUS_M);
+    }
+
+    return length;
+}
+
+- (CLLocationDirection)direction:(MGLRadianCoordinate2D)from to:(MGLRadianCoordinate2D)to
+{
+    return MGLDegreesFromRadians(MGLRadianCoordinatesDirection(from, to));
+}
+
 @end
 
 @interface MGLMultiPolyline ()
@@ -114,6 +170,15 @@ - (NSUInteger)hash {
     return hash;
 }
 
+- (CLLocationCoordinate2D)coordinate {
+    MGLPolyline *polyline = self.polylines.firstObject;
+    CLLocationCoordinate2D *coordinates = polyline.coordinates;
+    NSAssert([polyline pointCount] > 0, @"Polyline must have coordinates");
+    CLLocationCoordinate2D firstCoordinate = coordinates[0];
+
+    return firstCoordinate;
+}
+
 - (BOOL)intersectsOverlayBounds:(MGLCoordinateBounds)overlayBounds {
     return MGLCoordinateBoundsIntersectsCoordinateBounds(_overlayBounds, overlayBounds);
 }

platform/darwin/test/MGLCodingTests.m

@@ -66,12 +66,54 @@ - (void)testPolyline {
     [unarchivedPolyline replaceCoordinatesInRange:NSMakeRange(0, 1) withCoordinates:otherCoordinates];
 
     XCTAssertNotEqualObjects(polyline, unarchivedPolyline);
+
+    CLLocationCoordinate2D multiLineCoordinates[] = {
+        CLLocationCoordinate2DMake(51.000000, 0.000000),
+        CLLocationCoordinate2DMake(51.000000, 1.000000),
+        CLLocationCoordinate2DMake(51.000000, 2.000000),
+    };
+
+    NSUInteger multiLineCoordinatesCount = sizeof(multiLineCoordinates) / sizeof(CLLocationCoordinate2D);
+    MGLPolyline *multiLine = [MGLPolyline polylineWithCoordinates:multiLineCoordinates count:multiLineCoordinatesCount];
+    CLLocationCoordinate2D multiLineCenter = CLLocationCoordinate2DMake(51.000000, 1.000000);
+
+    XCTAssertEqual([multiLine coordinate].latitude, multiLineCenter.latitude);
+    XCTAssertEqual([multiLine coordinate].longitude, multiLineCenter.longitude);
+
+    CLLocationCoordinate2D segmentCoordinates[] = {
+        CLLocationCoordinate2DMake(35.040390, -85.311477),
+        CLLocationCoordinate2DMake(35.040390, -85.209510),
+    };
+
+    NSUInteger segmentCoordinatesCount = sizeof(segmentCoordinates) / sizeof(CLLocationCoordinate2D);
+    MGLPolyline *segmentLine = [MGLPolyline polylineWithCoordinates:segmentCoordinates count:segmentCoordinatesCount];
+    CLLocationCoordinate2D segmentCenter = CLLocationCoordinate2DMake(35.0404006631, -85.2604935);
+
+    XCTAssertEqualWithAccuracy([segmentLine coordinate].latitude, segmentCenter.latitude, 0.0001);
+    XCTAssertEqualWithAccuracy([segmentLine coordinate].longitude, segmentCenter.longitude, 0.0001);
+
+    CLLocationCoordinate2D sfToBerkeleyCoordinates[] = {
+        CLLocationCoordinate2DMake(37.782440, -122.397111),
+        CLLocationCoordinate2DMake(37.818384, -122.352994),
+        CLLocationCoordinate2DMake(37.831401, -122.274545),
+        CLLocationCoordinate2DMake(37.862172, -122.262700),
+    };
+
+    NSUInteger sfToBerkeleyCoordinatesCount = sizeof(sfToBerkeleyCoordinates) / sizeof(CLLocationCoordinate2D);
+    MGLPolyline *sfToBerkeleyLine = [MGLPolyline polylineWithCoordinates:sfToBerkeleyCoordinates count:sfToBerkeleyCoordinatesCount];
+    CLLocationCoordinate2D sfToBerkeleyCenter = CLLocationCoordinate2DMake(37.8230575118,-122.324867587);
+
+    XCTAssertEqualWithAccuracy([sfToBerkeleyLine coordinate].latitude, sfToBerkeleyCenter.latitude, 0.0001);
+    XCTAssertEqualWithAccuracy([sfToBerkeleyLine coordinate].longitude, sfToBerkeleyCenter.longitude, 0.0001);
+
 }
 
 - (void)testPolygon {
     CLLocationCoordinate2D coordinates[] = {
-        CLLocationCoordinate2DMake(0.664482398, 1.8865675),
-        CLLocationCoordinate2DMake(2.13224687, 3.9984632)
+        CLLocationCoordinate2DMake(35.090745, -85.300259),
+        CLLocationCoordinate2DMake(35.092035, -85.298885),
+        CLLocationCoordinate2DMake(35.090639, -85.297416),
+        CLLocationCoordinate2DMake(35.089112, -85.298928)
     };
 
     NSUInteger numberOfCoordinates = sizeof(coordinates) / sizeof(CLLocationCoordinate2D);
@@ -84,8 +126,24 @@ - (void)testPolygon {
     [NSKeyedArchiver archiveRootObject:polygon toFile:filePath];
 
     MGLPolygon *unarchivedPolygon = [NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
+    [unarchivedPolygon coordinate];
 
     XCTAssertEqualObjects(polygon, unarchivedPolygon);
+
+    CLLocationCoordinate2D squareCoordinates[] = {
+        CLLocationCoordinate2DMake(100.0, 0.0),
+        CLLocationCoordinate2DMake(101.0, 0.0),
+        CLLocationCoordinate2DMake(101.0, 1.0),
+        CLLocationCoordinate2DMake(100.0, 1.0),
+    };
+
+    NSUInteger squareCoordinatesCount = sizeof(squareCoordinates) / sizeof(CLLocationCoordinate2D);
+    MGLPolygon *squarePolygon = [MGLPolygon polygonWithCoordinates:squareCoordinates count:squareCoordinatesCount];
+    CLLocationCoordinate2D squareCenter = CLLocationCoordinate2DMake(100.5, 0.5);
+
+    XCTAssertEqual([squarePolygon coordinate].latitude, squareCenter.latitude);
+    XCTAssertEqual([squarePolygon coordinate].longitude, squareCenter.longitude);
+
 }
 
 - (void)testPolygonWithInteriorPolygons {
@@ -169,6 +227,11 @@ - (void)testPointCollection {
     NSUInteger numberOfCoordinates = sizeof(coordinates) / sizeof(CLLocationCoordinate2D);
 
     MGLPointCollection *pointCollection = [MGLPointCollection pointCollectionWithCoordinates:coordinates count:numberOfCoordinates];
+    CLLocationCoordinate2D pointsCenter = CLLocationCoordinate2DMake(0, 1);
+
+    XCTAssertEqual([pointCollection coordinate].latitude, pointsCenter.latitude);
+    XCTAssertEqual([pointCollection coordinate].longitude, pointsCenter.longitude);
+
     NSString *filePath = [self temporaryFilePathForClass:[MGLPointCollection class]];
     [NSKeyedArchiver archiveRootObject:pointCollection toFile:filePath];
 
@@ -218,6 +281,30 @@ - (void)testMultiPolyline {
         CLLocationCoordinate2DMake(20, 21),
         CLLocationCoordinate2DMake(30, 31),
     };
+
+    CLLocationCoordinate2D line1[] = {
+        CLLocationCoordinate2DMake(100, 40),
+        CLLocationCoordinate2DMake(105, 45),
+        CLLocationCoordinate2DMake(110, 55)
+    };
+
+    CLLocationCoordinate2D line2[] = {
+        CLLocationCoordinate2DMake(105, 40),
+        CLLocationCoordinate2DMake(110, 45),
+        CLLocationCoordinate2DMake(115, 55)
+    };
+
+    NSUInteger road1CoordinatesCount = sizeof(line1) / sizeof(CLLocationCoordinate2D);
+    NSUInteger road2CoordinatesCount = sizeof(line2) / sizeof(CLLocationCoordinate2D);
+
+    MGLPolyline *road1Polyline = [MGLPolyline polylineWithCoordinates:line1 count:road1CoordinatesCount];
+    MGLPolyline *road2Polyline = [MGLPolyline polylineWithCoordinates:line1 count:road2CoordinatesCount];
+
+    MGLMultiPolyline *roads = [MGLMultiPolyline multiPolylineWithPolylines:@[road1Polyline, road2Polyline]];
+    CLLocationCoordinate2D roadCenter = CLLocationCoordinate2DMake(100, 40);
+
+    XCTAssertEqual([roads coordinate].latitude, roadCenter.latitude);
+    XCTAssertEqual([roads coordinate].longitude, roadCenter.longitude);
 
     NSUInteger numberOfCoordinates = sizeof(coordinates) / sizeof(CLLocationCoordinate2D);
 
@@ -248,6 +335,31 @@ - (void)testMultiPolygon {
         CLLocationCoordinate2DMake(20, 21),
         CLLocationCoordinate2DMake(30, 31),
     };
+
+    CLLocationCoordinate2D outerSquare[] = {
+        CLLocationCoordinate2DMake(100.0, 0.0),
+        CLLocationCoordinate2DMake(101.0, 0.0),
+        CLLocationCoordinate2DMake(101.0, 1.0),
+        CLLocationCoordinate2DMake(100.0, 1.0),
+    };
+
+    CLLocationCoordinate2D innerSquare[] = {
+        CLLocationCoordinate2DMake(100.35, 0.35),
+        CLLocationCoordinate2DMake(100.65, 0.35),
+        CLLocationCoordinate2DMake(100.65, 0.65),
+        CLLocationCoordinate2DMake(100.35, 0.65),
+    };
+
+    NSUInteger outerCoordinatesCount = sizeof(outerSquare) / sizeof(CLLocationCoordinate2D);
+    NSUInteger innerCoordinatesCount = sizeof(innerSquare) / sizeof(CLLocationCoordinate2D);
+
+    MGLPolygon *innerPolygonSquare = [MGLPolygon polygonWithCoordinates:innerSquare count:innerCoordinatesCount];
+    MGLPolygon *outerPolygonSquare = [MGLPolygon polygonWithCoordinates:outerSquare count:outerCoordinatesCount interiorPolygons:@[innerPolygonSquare]];
+    MGLMultiPolygon *squares = [MGLMultiPolygon multiPolygonWithPolygons:@[outerPolygonSquare, innerPolygonSquare]];
+    CLLocationCoordinate2D squareCenter = CLLocationCoordinate2DMake(100.5, 0.5);
+
+    XCTAssertEqual([squares coordinate].latitude, squareCenter.latitude);
+    XCTAssertEqual([squares coordinate].longitude, squareCenter.longitude);
 
     NSUInteger numberOfCoordinates = sizeof(coordinates) / sizeof(CLLocationCoordinate2D);
 
@@ -265,9 +377,10 @@ - (void)testMultiPolygon {
 
     MGLMultiPolygon *unarchivedMultiPolygon = [NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
     MGLMultiPolygon *anotherMultiPolygon = [MGLMultiPolygon multiPolygonWithPolygons:[polygons subarrayWithRange:NSMakeRange(0, polygons.count/2)]];
-
+    
     XCTAssertEqualObjects(multiPolygon, unarchivedMultiPolygon);
     XCTAssertNotEqualObjects(anotherMultiPolygon, unarchivedMultiPolygon);
+
 }
 
 - (void)testShapeCollection {

platform/ios/CHANGELOG.md

@@ -32,6 +32,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 ### Other changes
 
 * Xcode 8.0 or higher is now recommended for using this SDK. ([#8775](https://github.com/mapbox/mapbox-gl-native/pull/8775))
+* Fixed a crash when calling `MGLMultiPolygon.coordinate` [#8713](https://github.com/mapbox/mapbox-gl-native/pull/8713)
 * Updated MGLMapView’s logo view to display [the new Mapbox logo](https://www.mapbox.com/blog/new-mapbox-logo/). ([#8771](https://github.com/mapbox/mapbox-gl-native/pull/8771), [#8773](https://github.com/mapbox/mapbox-gl-native/pull/8773))
 * Fixed a crash or console spew when MGLMapView is initialized with a frame smaller than 64 points wide by 64 points tall. ([#8562](https://github.com/mapbox/mapbox-gl-native/pull/8562))
 * The error passed into `-[MGLMapViewDelegate mapViewDidFailLoadingMap:withError:]` now includes a more specific description and failure reason. ([#8418](https://github.com/mapbox/mapbox-gl-native/pull/8418))