[ios, osx] Geometry value methods

Added category methods on NSValue for converting to and from the structure types defined in MGLGeometry.h.

Fixes #4485.

platform/darwin/include/MGLGeometry.h

@@ -95,4 +95,53 @@ NS_INLINE CLLocationDegrees MGLDegreesFromRadians(CGFloat radians) {
     return radians * 180 / M_PI;
 }
 
+/**
+ Methods for round-tripping Mapbox geometry structure values.
+ */
+@interface NSValue (MGLGeometryAdditions)
+
+/**
+ Creates a new value object containing the specified Core Location geographic
+ coordinate structure.
+ 
+ @param coordinate The value for the new object.
+ @return A new value object that contains the geographic coordinate information.
+ */
++ (instancetype)valueWithMGLCoordinate:(CLLocationCoordinate2D)coordinate;
+
+/**
+ The Core Location geographic coordinate structure representation of the value.
+ */
+@property (readonly) CLLocationCoordinate2D MGLCoordinateValue;
+
+/**
+ Creates a new value object containing the specified Mapbox coordinate span
+ structure.
+ 
+ @param span The value for the new object.
+ @return A new value object that contains the coordinate span information.
+ */
++ (instancetype)valueWithMGLCoordinateSpan:(MGLCoordinateSpan)span;
+
+/**
+ The Mapbox coordinate span structure representation of the value.
+ */
+@property (readonly) MGLCoordinateSpan MGLCoordinateSpanValue;
+
+/**
+ Creates a new value object containing the specified Mapbox coordinate bounds
+ structure.
+ 
+ @param bounds The value for the new object.
+ @return A new value object that contains the coordinate bounds information.
+ */
++ (instancetype)valueWithMGLCoordinateBounds:(MGLCoordinateBounds)bounds;
+
+/**
+ The Mapbox coordinate bounds structure representation of the value.
+ */
+@property (readonly) MGLCoordinateBounds MGLCoordinateBoundsValue;
+
+@end
+
 NS_ASSUME_NONNULL_END

platform/darwin/src/MGLGeometry.mm

@@ -44,3 +44,38 @@ double MGLZoomLevelForAltitude(CLLocationDistance altitude, CGFloat pitch, CLLoc
     CGFloat mapPixelWidthAtZoom = std::cos(MGLRadiansFromDegrees(latitude)) * mbgl::util::M2PI * mbgl::util::EARTH_RADIUS_M / metersPerPixel;
     return ::log2(mapPixelWidthAtZoom / mbgl::util::tileSize);
 }
+
+@implementation NSValue (MGLGeometryAdditions)
+
++ (instancetype)valueWithMGLCoordinate:(CLLocationCoordinate2D)coordinate {
+    return [self valueWithBytes:&coordinate objCType:@encode(CLLocationCoordinate2D)];
+}
+
+- (CLLocationCoordinate2D)MGLCoordinateValue {
+    CLLocationCoordinate2D coordinate;
+    [self getValue:&coordinate];
+    return coordinate;
+}
+
++ (instancetype)valueWithMGLCoordinateSpan:(MGLCoordinateSpan)span {
+    return [self valueWithBytes:&span objCType:@encode(MGLCoordinateSpan)];
+}
+
+- (MGLCoordinateSpan)MGLCoordinateSpanValue {
+    MGLCoordinateSpan span;
+    [self getValue:&span];
+    return span;
+}
+
++ (instancetype)valueWithMGLCoordinateBounds:(MGLCoordinateBounds)bounds {
+    return [self valueWithBytes:&bounds objCType:@encode(MGLCoordinateBounds)];
+}
+
+- (MGLCoordinateBounds)MGLCoordinateBoundsValue {
+    MGLCoordinateBounds bounds;
+    [self getValue:&bounds];
+    return bounds;
+}
+
+@end
+

platform/ios/ios.xcodeproj/project.pbxproj

@@ -377,7 +377,7 @@
 		DABCABBB1CB80692000A7C39 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		DABCABBF1CB80717000A7C39 /* locations.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = locations.cpp; sourceTree = "<group>"; };
 		DABCABC01CB80717000A7C39 /* locations.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = locations.hpp; sourceTree = "<group>"; };
-		DAC07C961CBB2CD6000CB309 /* mbgl.xcconfig */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xcconfig; name = mbgl.xcconfig; path = "../../build/ios/mbgl.xcconfig"; sourceTree = "<group>"; };
+		DAC07C961CBB2CD6000CB309 /* mbgl.xcconfig */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xcconfig; name = mbgl.xcconfig; path = ../../build/ios/mbgl.xcconfig; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -1188,7 +1188,7 @@
 				MTL_ENABLE_DEBUG_INFO = YES;
 				ONLY_ACTIVE_ARCH = YES;
 				SDKROOT = iphoneos;
-				SYMROOT = "../../build/ios";
+				SYMROOT = ../../build/ios;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -1227,7 +1227,7 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 7.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
-				SYMROOT = "../../build/ios";
+				SYMROOT = ../../build/ios;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VALIDATE_PRODUCT = YES;
 			};