[ios] adapt Mapbox Streets–sourced layers for user preferred language (#9582)

* [ios] Update label localization

* [ios, macos] Move MGLVectorSource+MBXAdditions.h to darwin.

* [ios, macos] Adapt Mapbox Streets to the user preferred language.

* [ios, macos] Clarify style localization documentation.

* [ios, macos] Update localization examples

* [ios, macos] Add style language reset to original.

* [ios, macos] Update changelogs.

* [ios, macos] Rename Vector Source Additions to MGL standard.

* [ios, macos] Add suport for stop localization.

10 files changed, 188 insertions, 97 deletions

diff --git a/platform/darwin/src/MGLStyle.h b/platform/darwin/src/MGLStyle.h
index 8ffd7db2b2..8c009d22c6 100644
--- a/platform/darwin/src/MGLStyle.h
+++ b/platform/darwin/src/MGLStyle.h
@@ -610,6 +610,21 @@ MGL_EXPORT
  */
 @property (nonatomic, strong) MGLLight *light;
 
+#pragma mark Localizing Map Content
+
+/**
+ A Boolean value that determines whether the style attempts to localize labels in 
+ the style into the system’s preferred language.
+ 
+ When this property is enabled, the style automatically modifies the text property 
+ of any symbol style layer whose source is the 
+ <a href="https://www.mapbox.com/vector-tiles/mapbox-streets-v7/#overview">Mapbox 
+ Streets source</a>. On iOS, the user can set the system’s preferred language in 
+ Settings, General Settings, Language & Region. On macOS, the user can set the 
+ system’s preferred language in the Language & Region pane of System Preferences.
+ */
+@property (nonatomic) BOOL localizesLabels;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/platform/darwin/src/MGLStyle.mm b/platform/darwin/src/MGLStyle.mm
index eb838085d7..1e0a2e02b7 100644
--- a/platform/darwin/src/MGLStyle.mm
+++ b/platform/darwin/src/MGLStyle.mm
@@ -21,6 +21,7 @@
 #import "MGLSource.h"
 #import "MGLTileSource_Private.h"
 #import "MGLVectorSource.h"
+#import "MGLVectorSource+MGLAdditions.h"
 #import "MGLRasterSource.h"
 #import "MGLShapeSource.h"
 
@@ -48,11 +49,34 @@
     #import "NSImage+MGLAdditions.h"
 #endif
 
+/**
+ Model class for localization changes.
+ */
+@interface MGLTextLanguage: NSObject
+@property (strong, nonatomic) NSString *originalTextField;
+@property (strong, nonatomic) NSString *updatedTextField;
+
+- (instancetype)initWithTextLanguage:(NSString *)originalTextField updatedTextField:(NSString *)updatedTextField;
+
+@end
+
+@implementation MGLTextLanguage
+- (instancetype)initWithTextLanguage:(NSString *)originalTextField updatedTextField:(NSString *)updatedTextField
+{
+    if (self = [super init]) {
+        _originalTextField = originalTextField;
+        _updatedTextField = updatedTextField;
+    }
+    return self;
+}
+@end
+
 @interface MGLStyle()
 
 @property (nonatomic, readwrite, weak) MGLMapView *mapView;
 @property (readonly, copy, nullable) NSURL *URL;
 @property (nonatomic, readwrite, strong) NS_MUTABLE_DICTIONARY_OF(NSString *, MGLOpenGLStyleLayer *) *openGLLayers;
+@property (nonatomic) NS_MUTABLE_DICTIONARY_OF(NSString *, NS_DICTIONARY_OF(NSObject *, MGLTextLanguage *) *) *localizedLayersByIdentifier;
 
 @end
 
@@ -116,6 +140,7 @@ static NSURL *MGLStyleURL_emerald;
     if (self = [super init]) {
         _mapView = mapView;
         _openGLLayers = [NSMutableDictionary dictionary];
+        _localizedLayersByIdentifier = [NSMutableDictionary dictionary];
     }
     return self;
 }
@@ -609,4 +634,115 @@ static NSURL *MGLStyleURL_emerald;
             self.URL ? [NSString stringWithFormat:@"\"%@\"", self.URL] : self.URL];
 }
 
+#pragma mark Style language preferences
+
+- (void)setLocalizesLabels:(BOOL)localizesLabels
+{
+    if (_localizesLabels != localizesLabels) {
+        _localizesLabels = localizesLabels;
+    } else {
+        return;
+    }
+    
+    if (_localizesLabels) {
+        NSString *preferredLanguage = [MGLVectorSource preferredMapboxStreetsLanguage];
+        NSMutableDictionary *localizedKeysByKeyBySourceIdentifier = [NSMutableDictionary dictionary];
+        for (MGLSymbolStyleLayer *layer in self.layers) {
+            if (![layer isKindOfClass:[MGLSymbolStyleLayer class]]) {
+                continue;
+            }
+            
+            MGLVectorSource *source = (MGLVectorSource *)[self sourceWithIdentifier:layer.sourceIdentifier];
+            if (![source isKindOfClass:[MGLVectorSource class]] || !source.mapboxStreets) {
+                continue;
+            }
+            
+            NSDictionary *localizedKeysByKey = localizedKeysByKeyBySourceIdentifier[layer.sourceIdentifier];
+            if (!localizedKeysByKey) {
+                localizedKeysByKey = localizedKeysByKeyBySourceIdentifier[layer.sourceIdentifier] = [source localizedKeysByKeyForPreferredLanguage:preferredLanguage];
+            }
+            
+            NSString *(^stringByLocalizingString)(NSString *) = ^ NSString * (NSString *string) {
+                NSMutableString *localizedString = string.mutableCopy;
+                [localizedKeysByKey enumerateKeysAndObjectsUsingBlock:^(NSString * _Nonnull key, NSString * _Nonnull localizedKey, BOOL * _Nonnull stop) {
+                    NSAssert([key isKindOfClass:[NSString class]], @"key is not a string");
+                    NSAssert([localizedKey isKindOfClass:[NSString class]], @"localizedKey is not a string");
+                    [localizedString replaceOccurrencesOfString:[NSString stringWithFormat:@"{%@}", key]
+                                                     withString:[NSString stringWithFormat:@"{%@}", localizedKey]
+                                                        options:0
+                                                          range:NSMakeRange(0, localizedString.length)];
+                }];
+                return localizedString;
+            };
+            
+            if ([layer.text isKindOfClass:[MGLConstantStyleValue class]]) {
+                NSString *textField = [(MGLConstantStyleValue<NSString *> *)layer.text rawValue];
+                NSString *localizingString = stringByLocalizingString(textField);
+                if (![textField isEqualToString:localizingString]) {
+                    MGLTextLanguage *textLanguage = [[MGLTextLanguage alloc] initWithTextLanguage:textField
+                                                                                 updatedTextField:localizingString];
+                    [self.localizedLayersByIdentifier setObject:@{ textField : textLanguage } forKey:layer.identifier];
+                    layer.text = [MGLStyleValue<NSString *> valueWithRawValue:localizingString];
+                }
+            }
+            else if ([layer.text isKindOfClass:[MGLCameraStyleFunction class]]) {
+                MGLCameraStyleFunction *function = (MGLCameraStyleFunction<NSString *> *)layer.text;
+                NSMutableDictionary *stops = function.stops.mutableCopy;
+                NSMutableDictionary *cameraStops = [NSMutableDictionary dictionary];
+                [stops enumerateKeysAndObjectsUsingBlock:^(NSNumber *zoomLevel, MGLConstantStyleValue<NSString *> *stop, BOOL *done) {
+                    NSString *textField = stop.rawValue;
+                    NSString *localizingString = stringByLocalizingString(textField);
+                    if (![textField isEqualToString:localizingString]) {
+                        MGLTextLanguage *textLanguage = [[MGLTextLanguage alloc] initWithTextLanguage:textField
+                                                                                     updatedTextField:localizingString];
+                        [cameraStops setObject:textLanguage forKey:zoomLevel];
+                        stops[zoomLevel] = [MGLStyleValue<NSString *> valueWithRawValue:localizingString];
+                    }
+                    
+                }];
+                if (cameraStops.count > 0) {
+                    [self.localizedLayersByIdentifier setObject:cameraStops forKey:layer.identifier];
+                }
+                function.stops = stops;
+                layer.text = function;
+            }
+        }
+    } else {
+        
+        [self.localizedLayersByIdentifier enumerateKeysAndObjectsUsingBlock:^(NSString *identifier, NSDictionary<NSObject *, MGLTextLanguage *> *textFields, BOOL *done) {
+            MGLSymbolStyleLayer *layer = (MGLSymbolStyleLayer *)[self.mapView.style layerWithIdentifier:identifier];
+            
+            if ([layer.text isKindOfClass:[MGLConstantStyleValue class]]) {
+                NSString *textField = [(MGLConstantStyleValue<NSString *> *)layer.text rawValue];
+                [textFields enumerateKeysAndObjectsUsingBlock:^(NSObject *originalLanguage, MGLTextLanguage *textLanguage, BOOL *done) {
+                    if ([textLanguage.updatedTextField isEqualToString:textField]) {
+                        layer.text = [MGLStyleValue<NSString *> valueWithRawValue:textLanguage.originalTextField];
+                    }
+                }];
+
+            }
+            else if ([layer.text isKindOfClass:[MGLCameraStyleFunction class]]) {
+                MGLCameraStyleFunction *function = (MGLCameraStyleFunction<NSString *> *)layer.text;
+                NSMutableDictionary *stops = function.stops.mutableCopy;
+                [textFields enumerateKeysAndObjectsUsingBlock:^(NSObject *zoomKey, MGLTextLanguage *textLanguage, BOOL *done) {
+                    if ([zoomKey isKindOfClass:[NSNumber class]]) {
+                        NSNumber *zoomLevel = (NSNumber*)zoomKey;
+                        MGLConstantStyleValue<NSString *> *stop = [stops objectForKey:zoomLevel];
+                        NSString *textField = stop.rawValue;
+                        if ([textLanguage.updatedTextField isEqualToString:textField]) {
+                            stops[zoomLevel] = [MGLStyleValue<NSString *> valueWithRawValue:textLanguage.originalTextField];
+                        }
+                    }
+                }];
+
+                function.stops = stops;
+                layer.text = function;
+            }
+
+        }];
+
+        self.localizedLayersByIdentifier = [NSMutableDictionary dictionary];
+    }
+}
+
 @end
diff --git a/platform/macos/app/MGLVectorSource+MBXAdditions.h b/platform/darwin/src/MGLVectorSource+MGLAdditions.h
index 1e25ee5a60..43b0aba747 100644
--- a/platform/macos/app/MGLVectorSource+MBXAdditions.h
+++ b/platform/darwin/src/MGLVectorSource+MGLAdditions.h
@@ -2,7 +2,7 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-@interface MGLVectorSource (MBXAdditions)
+@interface MGLVectorSource (MGLAdditions)
 
 + (NSString *)preferredMapboxStreetsLanguage;
 
diff --git a/platform/macos/app/MGLVectorSource+MBXAdditions.m b/platform/darwin/src/MGLVectorSource+MGLAdditions.m
index 323bc74366..a305388117 100644
--- a/platform/macos/app/MGLVectorSource+MBXAdditions.m
+++ b/platform/darwin/src/MGLVectorSource+MGLAdditions.m
@@ -1,6 +1,6 @@
-#import "MGLVectorSource+MBXAdditions.h"
+#import "MGLVectorSource+MGLAdditions.h"
 
-@implementation MGLVectorSource (MBXAdditions)
+@implementation MGLVectorSource (MGLAdditions)
 
 + (NS_SET_OF(NSString *) *)mapboxStreetsLanguages {
     // https://www.mapbox.com/vector-tiles/mapbox-streets-v7/#overview
diff --git a/platform/ios/CHANGELOG.md b/platform/ios/CHANGELOG.md
index 43df49a9ac..55790577cd 100644
--- a/platform/ios/CHANGELOG.md
+++ b/platform/ios/CHANGELOG.md
@@ -2,7 +2,11 @@
 
 Mapbox welcomes participation and contributions from everyone. Please read [CONTRIBUTING.md](../../CONTRIBUTING.md) to get started.
 
-## 3.6.1
+## 3.6.2
+
+* Added an MGLStyle.localizesLabels property, off by default, that localizes any Mapbox Streets–sourced symbol layer into the user’s preferred language. ([#9582](https://github.com/mapbox/mapbox-gl-native/pull/9582))
+
+## 3.6.1 - July 28, 2017
 
 * Reduced the size of the dynamic framework by optimizing symbol visibility. ([#7604](https://github.com/mapbox/mapbox-gl-native/pull/7604))
 * Fixed an issue where the attribution button would have its custom tint color reset when the map view received a tint color change notification, such as when an alert controller was presented. ([#9598](https://github.com/mapbox/mapbox-gl-native/pull/9598))
diff --git a/platform/ios/app/MBXViewController.m b/platform/ios/app/MBXViewController.m
index d3927374a7..ebbc218017 100644
--- a/platform/ios/app/MBXViewController.m
+++ b/platform/ios/app/MBXViewController.m
@@ -343,7 +343,7 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
                 @"Update Shape Source: Features",
                 @"Style Vector Source",
                 @"Style Raster Source",
-                [NSString stringWithFormat:@"Label Countries in %@", (_usingLocaleBasedCountryLabels ? @"Local Language" : [[NSLocale currentLocale] displayNameForKey:NSLocaleIdentifier value:[self bestLanguageForUser]])],
+                [NSString stringWithFormat:@"Show Labels in %@", (_usingLocaleBasedCountryLabels ? @"Local Language" : [[NSLocale currentLocale] displayNameForKey:NSLocaleIdentifier value:[self bestLanguageForUser]])],
                 @"Add Route Line",
                 @"Dynamically Style Polygon",
             ]];
@@ -1274,12 +1274,8 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
 
 -(void)styleCountryLabelsLanguage
 {
-    NSArray<NSString *> *labelLayers = @[
-        @"country-label-lg",
-        @"country-label-md",
-        @"country-label-sm",
-    ];
-    [self styleLabelLanguageForLayersNamed:labelLayers];
+    _usingLocaleBasedCountryLabels = !_usingLocaleBasedCountryLabels;
+    self.mapView.style.localizesLabels = _usingLocaleBasedCountryLabels;
 }
 
 - (void)styleRouteLine
@@ -1362,39 +1358,6 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
     [self.mapView.style addLayer:fillStyleLayer];
 }
 
-- (void)styleLabelLanguageForLayersNamed:(NSArray<NSString *> *)layers
-{
-    _usingLocaleBasedCountryLabels = !_usingLocaleBasedCountryLabels;
-    NSString *bestLanguageForUser = [NSString stringWithFormat:@"{name_%@}", [self bestLanguageForUser]];
-    NSString *language = _usingLocaleBasedCountryLabels ? bestLanguageForUser : @"{name}";
-
-    for (NSString *layerName in layers) {
-        MGLSymbolStyleLayer *layer = (MGLSymbolStyleLayer *)[self.mapView.style layerWithIdentifier:layerName];
-
-        if ([layer isKindOfClass:[MGLSymbolStyleLayer class]]) {
-            if ([layer.text isKindOfClass:[MGLConstantStyleValue class]]) {
-                MGLConstantStyleValue *label = (MGLConstantStyleValue<NSString *> *)layer.text;
-                if ([label.rawValue hasPrefix:@"{name"]) {
-                    layer.text = [MGLStyleValue valueWithRawValue:language];
-                }
-            }
-            else if ([layer.text isKindOfClass:[MGLCameraStyleFunction class]]) {
-                MGLCameraStyleFunction *function = (MGLCameraStyleFunction<NSString *> *)layer.text;
-                NSMutableDictionary *stops = function.stops.mutableCopy;
-                [stops enumerateKeysAndObjectsUsingBlock:^(NSNumber *zoomLevel, MGLConstantStyleValue<NSString *> *stop, BOOL *done) {
-                    if ([stop.rawValue hasPrefix:@"{name"]) {
-                        stops[zoomLevel] = [MGLStyleValue<NSString *> valueWithRawValue:language];
-                    }
-                }];
-                function.stops = stops;
-                layer.text = function;
-            }
-        } else {
-            NSLog(@"%@ is not a symbol style layer", layerName);
-        }
-    }
-}
-
 - (NSString *)bestLanguageForUser
 {
     // https://www.mapbox.com/vector-tiles/mapbox-streets-v7/#overview
diff --git a/platform/ios/ios.xcodeproj/project.pbxproj b/platform/ios/ios.xcodeproj/project.pbxproj
index 8ecbe0c6ab..83b267df43 100644
--- a/platform/ios/ios.xcodeproj/project.pbxproj
+++ b/platform/ios/ios.xcodeproj/project.pbxproj
@@ -17,6 +17,10 @@
 		1F7454971ECD450D00021D39 /* MGLLight_Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 1F7454941ECD450D00021D39 /* MGLLight_Private.h */; };
 		1F7454A91ED08AB400021D39 /* MGLLightTest.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1F7454A61ED08AB400021D39 /* MGLLightTest.mm */; };
 		1F95931D1E6DE2E900D5B294 /* MGLNSDateAdditionsTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1F95931C1E6DE2E900D5B294 /* MGLNSDateAdditionsTests.mm */; };
+		1FB7DAAF1F2A4DBD00410606 /* MGLVectorSource+MGLAdditions.h in Headers */ = {isa = PBXBuildFile; fileRef = 1FDD9D6D1F26936400252B09 /* MGLVectorSource+MGLAdditions.h */; };
+		1FB7DAB01F2A4DC200410606 /* MGLVectorSource+MGLAdditions.h in Headers */ = {isa = PBXBuildFile; fileRef = 1FDD9D6D1F26936400252B09 /* MGLVectorSource+MGLAdditions.h */; };
+		1FB7DAB11F2A4DC800410606 /* MGLVectorSource+MGLAdditions.m in Sources */ = {isa = PBXBuildFile; fileRef = 1FDD9D6E1F26936400252B09 /* MGLVectorSource+MGLAdditions.m */; };
+		1FB7DAB21F2A4DC900410606 /* MGLVectorSource+MGLAdditions.m in Sources */ = {isa = PBXBuildFile; fileRef = 1FDD9D6E1F26936400252B09 /* MGLVectorSource+MGLAdditions.m */; };
 		30E578171DAA85520050F07E /* UIImage+MGLAdditions.h in Headers */ = {isa = PBXBuildFile; fileRef = 30E578111DAA7D690050F07E /* UIImage+MGLAdditions.h */; };
 		30E578181DAA85520050F07E /* UIImage+MGLAdditions.h in Headers */ = {isa = PBXBuildFile; fileRef = 30E578111DAA7D690050F07E /* UIImage+MGLAdditions.h */; };
 		30E578191DAA855E0050F07E /* UIImage+MGLAdditions.mm in Sources */ = {isa = PBXBuildFile; fileRef = 30E578121DAA7D690050F07E /* UIImage+MGLAdditions.mm */; };
@@ -547,6 +551,8 @@
 		1F7454941ECD450D00021D39 /* MGLLight_Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MGLLight_Private.h; sourceTree = "<group>"; };
 		1F7454A61ED08AB400021D39 /* MGLLightTest.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; name = MGLLightTest.mm; path = ../../darwin/test/MGLLightTest.mm; sourceTree = "<group>"; };
 		1F95931C1E6DE2E900D5B294 /* MGLNSDateAdditionsTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; name = MGLNSDateAdditionsTests.mm; path = ../../darwin/test/MGLNSDateAdditionsTests.mm; sourceTree = "<group>"; };
+		1FDD9D6D1F26936400252B09 /* MGLVectorSource+MGLAdditions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "MGLVectorSource+MGLAdditions.h"; sourceTree = "<group>"; };
+		1FDD9D6E1F26936400252B09 /* MGLVectorSource+MGLAdditions.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "MGLVectorSource+MGLAdditions.m"; sourceTree = "<group>"; };
 		20DABE861DF78148007AC5FF /* zh-Hans */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = "zh-Hans"; path = "zh-Hans.lproj/Foundation.strings"; sourceTree = "<group>"; };
 		20DABE881DF78148007AC5FF /* zh-Hans */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = "zh-Hans"; path = "zh-Hans.lproj/Localizable.strings"; sourceTree = "<group>"; };
 		20DABE8A1DF78149007AC5FF /* zh-Hans */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = "zh-Hans"; path = "zh-Hans.lproj/Root.strings"; sourceTree = "<group>"; };
@@ -1537,6 +1543,8 @@
 		DAD165831CF4CFED001FF4B9 /* Categories */ = {
 			isa = PBXGroup;
 			children = (
+				1FDD9D6D1F26936400252B09 /* MGLVectorSource+MGLAdditions.h */,
+				1FDD9D6E1F26936400252B09 /* MGLVectorSource+MGLAdditions.m */,
 				7E016D821D9E890300A29A21 /* MGLPolygon+MGLAdditions.h */,
 				7E016D831D9E890300A29A21 /* MGLPolygon+MGLAdditions.m */,
 				7E016D7C1D9E86BE00A29A21 /* MGLPolyline+MGLAdditions.h */,
@@ -1642,6 +1650,7 @@
 				350098DC1D484E60004B2AF0 /* NSValue+MGLStyleAttributeAdditions.h in Headers */,
 				DA8848231CBAFA6200AB86E3 /* MGLOfflineStorage_Private.h in Headers */,
 				404326891D5B9B27007111BD /* MGLAnnotationContainerView_Private.h in Headers */,
+				1FB7DAAF1F2A4DBD00410606 /* MGLVectorSource+MGLAdditions.h in Headers */,
 				DA88483B1CBAFB8500AB86E3 /* MGLCalloutView.h in Headers */,
 				35E0CFE61D3E501500188327 /* MGLStyle_Private.h in Headers */,
 				3510FFF01D6D9D8C00F413B2 /* NSExpression+MGLAdditions.h in Headers */,
@@ -1819,6 +1828,7 @@
 				35136D4D1D4277FC00C20EFD /* MGLSource.h in Headers */,
 				DA35A2BC1CCA9A6900E826B2 /* MGLClockDirectionFormatter.h in Headers */,
 				35D13AC41D3D19DD00AFB4E0 /* MGLFillStyleLayer.h in Headers */,
+				1FB7DAB01F2A4DC200410606 /* MGLVectorSource+MGLAdditions.h in Headers */,
 				DABFB86E1CBE9A0F00D62B32 /* MGLCalloutView.h in Headers */,
 				1F7454971ECD450D00021D39 /* MGLLight_Private.h in Headers */,
 				DABFB8601CBE99E500D62B32 /* MGLMapCamera.h in Headers */,
@@ -2197,6 +2207,7 @@
 				9620BB3A1E69FE1700705A1D /* MGLSDKUpdateChecker.mm in Sources */,
 				354B83981D2E873E005D9406 /* MGLUserLocationAnnotationView.m in Sources */,
 				DA88485D1CBAFB9800AB86E3 /* MGLFaux3DUserLocationAnnotationView.m in Sources */,
+				1FB7DAB11F2A4DC800410606 /* MGLVectorSource+MGLAdditions.m in Sources */,
 				DAD165701CF41981001FF4B9 /* MGLFeature.mm in Sources */,
 				30E578191DAA855E0050F07E /* UIImage+MGLAdditions.mm in Sources */,
 				40EDA1C11CFE0E0500D9EA68 /* MGLAnnotationContainerView.m in Sources */,
@@ -2279,6 +2290,7 @@
 				9620BB3B1E69FE1700705A1D /* MGLSDKUpdateChecker.mm in Sources */,
 				DAA4E4221CBB730400178DFB /* MGLPointAnnotation.mm in Sources */,
 				DAED38661D62D0FC00D7640F /* NSURL+MGLAdditions.m in Sources */,
+				1FB7DAB21F2A4DC900410606 /* MGLVectorSource+MGLAdditions.m in Sources */,
 				DAD165711CF41981001FF4B9 /* MGLFeature.mm in Sources */,
 				30E5781A1DAA855E0050F07E /* UIImage+MGLAdditions.mm in Sources */,
 				40EDA1C21CFE0E0500D9EA68 /* MGLAnnotationContainerView.m in Sources */,
diff --git a/platform/macos/CHANGELOG.md b/platform/macos/CHANGELOG.md
index f69f7e1b5d..1af3c03d68 100644
--- a/platform/macos/CHANGELOG.md
+++ b/platform/macos/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog for Mapbox macOS SDK
 
+## 0.5.1
+
+* Added an MGLStyle.localizesLabels property, off by default, that localizes any Mapbox Streets–sourced symbol layer into the user’s preferred language. ([#9582](https://github.com/mapbox/mapbox-gl-native/pull/9582))
+
 ## 0.5.0
 
 This version of the Mapbox macOS SDK corresponds to version 3.6.0 of the Mapbox iOS SDK.
diff --git a/platform/macos/app/MapDocument.m b/platform/macos/app/MapDocument.m
index 59844d363e..1d22295f50 100644
--- a/platform/macos/app/MapDocument.m
+++ b/platform/macos/app/MapDocument.m
@@ -5,7 +5,7 @@
 #import "DroppedPinAnnotation.h"
 
 #import "MGLStyle+MBXAdditions.h"
-#import "MGLVectorSource+MBXAdditions.h"
+#import "MGLVectorSource+MGLAdditions.h"
 
 #import <Mapbox/Mapbox.h>
 
@@ -344,52 +344,7 @@ NS_ARRAY_OF(id <MGLAnnotation>) *MBXFlattenedShapes(NS_ARRAY_OF(id <MGLAnnotatio
 }
 
 - (void)updateLabels {
-    MGLStyle *style = self.mapView.style;
-    NSString *preferredLanguage = _isLocalizingLabels ? [MGLVectorSource preferredMapboxStreetsLanguage] : nil;
-    NSMutableDictionary *localizedKeysByKeyBySourceIdentifier = [NSMutableDictionary dictionary];
-    for (MGLSymbolStyleLayer *layer in style.layers) {
-        if (![layer isKindOfClass:[MGLSymbolStyleLayer class]]) {
-            continue;
-        }
-
-        MGLVectorSource *source = (MGLVectorSource *)[style sourceWithIdentifier:layer.sourceIdentifier];
-        if (![source isKindOfClass:[MGLVectorSource class]] || !source.mapboxStreets) {
-            continue;
-        }
-
-        NSDictionary *localizedKeysByKey = localizedKeysByKeyBySourceIdentifier[layer.sourceIdentifier];
-        if (!localizedKeysByKey) {
-            localizedKeysByKey = localizedKeysByKeyBySourceIdentifier[layer.sourceIdentifier] = [source localizedKeysByKeyForPreferredLanguage:preferredLanguage];
-        }
-
-        NSString *(^stringByLocalizingString)(NSString *) = ^ NSString * (NSString *string) {
-            NSMutableString *localizedString = string.mutableCopy;
-            [localizedKeysByKey enumerateKeysAndObjectsUsingBlock:^(NSString * _Nonnull key, NSString * _Nonnull localizedKey, BOOL * _Nonnull stop) {
-                NSAssert([key isKindOfClass:[NSString class]], @"key is not a string");
-                NSAssert([localizedKey isKindOfClass:[NSString class]], @"localizedKey is not a string");
-                [localizedString replaceOccurrencesOfString:[NSString stringWithFormat:@"{%@}", key]
-                                                 withString:[NSString stringWithFormat:@"{%@}", localizedKey]
-                                                    options:0
-                                                      range:NSMakeRange(0, localizedString.length)];
-            }];
-            return localizedString;
-        };
-
-        if ([layer.text isKindOfClass:[MGLConstantStyleValue class]]) {
-            NSString *textField = [(MGLConstantStyleValue<NSString *> *)layer.text rawValue];
-            layer.text = [MGLStyleValue<NSString *> valueWithRawValue:stringByLocalizingString(textField)];
-        }
-        else if ([layer.text isKindOfClass:[MGLCameraStyleFunction class]]) {
-            MGLCameraStyleFunction *function = (MGLCameraStyleFunction<NSString *> *)layer.text;
-            NSMutableDictionary *stops = function.stops.mutableCopy;
-            [stops enumerateKeysAndObjectsUsingBlock:^(NSNumber *zoomLevel, MGLConstantStyleValue<NSString *> *stop, BOOL *done) {
-                NSString *textField = stop.rawValue;
-                stops[zoomLevel] = [MGLStyleValue<NSString *> valueWithRawValue:stringByLocalizingString(textField)];
-            }];
-            function.stops = stops;
-            layer.text = function;
-        }
-    }
+    self.mapView.style.localizesLabels = _isLocalizingLabels;
 }
 
 - (void)applyPendingState {
diff --git a/platform/macos/macos.xcodeproj/project.pbxproj b/platform/macos/macos.xcodeproj/project.pbxproj
index be33b822f2..00cb6ce975 100644
--- a/platform/macos/macos.xcodeproj/project.pbxproj
+++ b/platform/macos/macos.xcodeproj/project.pbxproj
@@ -13,6 +13,8 @@
 		1F7454A51ECFB00300021D39 /* MGLLight.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1F7454A21ECFB00300021D39 /* MGLLight.mm */; };
 		1F7454AB1ED1DDBD00021D39 /* MGLLightTest.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1F7454AA1ED1DDBD00021D39 /* MGLLightTest.mm */; };
 		1F95931B1E6DE2B600D5B294 /* MGLNSDateAdditionsTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1F95931A1E6DE2B600D5B294 /* MGLNSDateAdditionsTests.mm */; };
+		1FCDF1421F2A4F3600A46694 /* MGLVectorSource+MGLAdditions.h in Headers */ = {isa = PBXBuildFile; fileRef = 1FCDF1401F2A4F3600A46694 /* MGLVectorSource+MGLAdditions.h */; };
+		1FCDF1431F2A4F3600A46694 /* MGLVectorSource+MGLAdditions.m in Sources */ = {isa = PBXBuildFile; fileRef = 1FCDF1411F2A4F3600A46694 /* MGLVectorSource+MGLAdditions.m */; };
 		30E5781B1DAA857E0050F07E /* NSImage+MGLAdditions.h in Headers */ = {isa = PBXBuildFile; fileRef = 30E578141DAA7D920050F07E /* NSImage+MGLAdditions.h */; };
 		3508EC641D749D39009B0EE4 /* NSExpression+MGLAdditions.h in Headers */ = {isa = PBXBuildFile; fileRef = 3508EC621D749D39009B0EE4 /* NSExpression+MGLAdditions.h */; };
 		3508EC651D749D39009B0EE4 /* NSExpression+MGLAdditions.mm in Sources */ = {isa = PBXBuildFile; fileRef = 3508EC631D749D39009B0EE4 /* NSExpression+MGLAdditions.mm */; };
@@ -233,7 +235,6 @@
 		DAEDC4371D606291000224FF /* MGLAttributionButtonTests.m in Sources */ = {isa = PBXBuildFile; fileRef = DAEDC4361D606291000224FF /* MGLAttributionButtonTests.m */; };
 		DAF0D80E1DFE0E5D00B28378 /* MGLPointCollection_Private.h in Headers */ = {isa = PBXBuildFile; fileRef = DAF0D80D1DFE0E5D00B28378 /* MGLPointCollection_Private.h */; };
 		DAF0D8161DFE6B1800B28378 /* MGLAttributionInfo_Private.h in Headers */ = {isa = PBXBuildFile; fileRef = DAF0D8151DFE6B1800B28378 /* MGLAttributionInfo_Private.h */; };
-		DAF0D81C1DFF567C00B28378 /* MGLVectorSource+MBXAdditions.m in Sources */ = {isa = PBXBuildFile; fileRef = DAF0D81B1DFF567C00B28378 /* MGLVectorSource+MBXAdditions.m */; };
 		DD0902B21DB1AC6400C5BDCE /* MGLNetworkConfiguration.m in Sources */ = {isa = PBXBuildFile; fileRef = DD0902AF1DB1AC6400C5BDCE /* MGLNetworkConfiguration.m */; };
 		DD0902B31DB1AC6400C5BDCE /* MGLNetworkConfiguration.h in Headers */ = {isa = PBXBuildFile; fileRef = DD0902B01DB1AC6400C5BDCE /* MGLNetworkConfiguration.h */; };
 		DD58A4C91D822C6700E1F038 /* MGLExpressionTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = DD58A4C71D822C6200E1F038 /* MGLExpressionTests.mm */; };
@@ -277,6 +278,8 @@
 		1F7454A21ECFB00300021D39 /* MGLLight.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = MGLLight.mm; sourceTree = "<group>"; };
 		1F7454AA1ED1DDBD00021D39 /* MGLLightTest.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = MGLLightTest.mm; sourceTree = "<group>"; };
 		1F95931A1E6DE2B600D5B294 /* MGLNSDateAdditionsTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; name = MGLNSDateAdditionsTests.mm; path = ../../darwin/test/MGLNSDateAdditionsTests.mm; sourceTree = "<group>"; };
+		1FCDF1401F2A4F3600A46694 /* MGLVectorSource+MGLAdditions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "MGLVectorSource+MGLAdditions.h"; sourceTree = "<group>"; };
+		1FCDF1411F2A4F3600A46694 /* MGLVectorSource+MGLAdditions.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "MGLVectorSource+MGLAdditions.m"; sourceTree = "<group>"; };
 		30E578141DAA7D920050F07E /* NSImage+MGLAdditions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = "NSImage+MGLAdditions.h"; path = "src/NSImage+MGLAdditions.h"; sourceTree = SOURCE_ROOT; };
 		3508EC621D749D39009B0EE4 /* NSExpression+MGLAdditions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "NSExpression+MGLAdditions.h"; sourceTree = "<group>"; };
 		3508EC631D749D39009B0EE4 /* NSExpression+MGLAdditions.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = "NSExpression+MGLAdditions.mm"; sourceTree = "<group>"; };
@@ -568,8 +571,6 @@
 		DAEDC4361D606291000224FF /* MGLAttributionButtonTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MGLAttributionButtonTests.m; sourceTree = "<group>"; };
 		DAF0D80D1DFE0E5D00B28378 /* MGLPointCollection_Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MGLPointCollection_Private.h; sourceTree = "<group>"; };
 		DAF0D8151DFE6B1800B28378 /* MGLAttributionInfo_Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MGLAttributionInfo_Private.h; sourceTree = "<group>"; };
-		DAF0D81A1DFF567C00B28378 /* MGLVectorSource+MBXAdditions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "MGLVectorSource+MBXAdditions.h"; sourceTree = "<group>"; };
-		DAF0D81B1DFF567C00B28378 /* MGLVectorSource+MBXAdditions.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "MGLVectorSource+MBXAdditions.m"; sourceTree = "<group>"; };
 		DAFBD0D51E3FA969000CD6BF /* zh-Hant */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = "zh-Hant"; path = "zh-Hant.lproj/Localizable.strings"; sourceTree = "<group>"; };
 		DAFBD0D61E3FA983000CD6BF /* zh-Hant */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = "zh-Hant"; path = "zh-Hant.lproj/Foundation.strings"; sourceTree = "<group>"; };
 		DD0902AF1DB1AC6400C5BDCE /* MGLNetworkConfiguration.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MGLNetworkConfiguration.m; sourceTree = "<group>"; };
@@ -740,8 +741,6 @@
 				DA839E9E1CC2E3400062CAFB /* MapDocument.xib */,
 				DACB0C371E18DFFD005DDBEA /* MGLStyle+MBXAdditions.h */,
 				DACB0C381E18DFFD005DDBEA /* MGLStyle+MBXAdditions.m */,
-				DAF0D81A1DFF567C00B28378 /* MGLVectorSource+MBXAdditions.h */,
-				DAF0D81B1DFF567C00B28378 /* MGLVectorSource+MBXAdditions.m */,
 				DAE6C2E91CC3050F00DB3429 /* OfflinePackNameValueTransformer.h */,
 				DAE6C2EA1CC3050F00DB3429 /* OfflinePackNameValueTransformer.m */,
 				DAA48EFB1D6A4731006A7E36 /* StyleLayerIconTransformer.h */,
@@ -920,6 +919,8 @@
 		DAD1657F1CF4CF50001FF4B9 /* Categories */ = {
 			isa = PBXGroup;
 			children = (
+				1FCDF1401F2A4F3600A46694 /* MGLVectorSource+MGLAdditions.h */,
+				1FCDF1411F2A4F3600A46694 /* MGLVectorSource+MGLAdditions.m */,
 				408AA8601DAEED3300022900 /* MGLPolygon+MGLAdditions.h */,
 				408AA85C1DAEED3300022900 /* MGLPolygon+MGLAdditions.m */,
 				408AA8611DAEED3300022900 /* MGLPolyline+MGLAdditions.h */,
@@ -1154,6 +1155,7 @@
 				DAE6C3601CC31E0400DB3429 /* MGLOfflineRegion.h in Headers */,
 				DAE6C3681CC31E0400DB3429 /* MGLTilePyramidOfflineRegion.h in Headers */,
 				DA35A2CF1CCAAED300E826B2 /* NSValue+MGLAdditions.h in Headers */,
+				1FCDF1421F2A4F3600A46694 /* MGLVectorSource+MGLAdditions.h in Headers */,
 				DAE6C3A61CC31E9400DB3429 /* MGLMapViewDelegate.h in Headers */,
 				DAE6C38B1CC31E2A00DB3429 /* MGLOfflinePack_Private.h in Headers */,
 				558DE7A61E56161C00C7916D /* MGLFoundation_Private.h in Headers */,
@@ -1378,7 +1380,6 @@
 				DACB0C391E18DFFD005DDBEA /* MGLStyle+MBXAdditions.m in Sources */,
 				DA839E9A1CC2E3400062CAFB /* main.m in Sources */,
 				DA839E971CC2E3400062CAFB /* AppDelegate.m in Sources */,
-				DAF0D81C1DFF567C00B28378 /* MGLVectorSource+MBXAdditions.m in Sources */,
 				DAE6C2F01CC3050F00DB3429 /* OfflinePackNameValueTransformer.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -1394,6 +1395,7 @@
 				40B77E461DB11BCD003DA2FE /* NSArray+MGLAdditions.mm in Sources */,
 				DAE6C38C1CC31E2A00DB3429 /* MGLOfflinePack.mm in Sources */,
 				35D65C5B1D65AD5500722C23 /* NSDate+MGLAdditions.mm in Sources */,
+				1FCDF1431F2A4F3600A46694 /* MGLVectorSource+MGLAdditions.m in Sources */,
 				DD0902B21DB1AC6400C5BDCE /* MGLNetworkConfiguration.m in Sources */,
 				1F7454A51ECFB00300021D39 /* MGLLight.mm in Sources */,
 				DAE6C3B11CC31EF300DB3429 /* MGLAnnotationImage.m in Sources */,