Allow specifying multiple fonts or font families for local font rendering

platform/darwin/src/MGLMapSnapshotter.mm

@@ -725,9 +725,10 @@ - (void)configureWithOptions:(MGLMapSnapshotOptions *)options {
                    .withAssetPath(NSBundle.mainBundle.resourceURL.path.UTF8String);
 
     // Create the snapshotter
+    auto localFontFamilyName = config.localFontFamilyName ? std::string(config.localFontFamilyName.UTF8String) : nullptr;
     _delegateHost = std::make_unique<MGLMapSnapshotterDelegateHost>(self);
     _mbglMapSnapshotter = std::make_unique<mbgl::MapSnapshotter>(
-                                                                 size, pixelRatio, resourceOptions, *_delegateHost, config.localFontFamilyName);
+                                                                 size, pixelRatio, resourceOptions, *_delegateHost, localFontFamilyName);
 
     _mbglMapSnapshotter->setStyleURL(std::string(options.styleURL.absoluteString.UTF8String));
 

platform/darwin/src/MGLRendererConfiguration.h

@@ -1,8 +1,6 @@
 #import "MGLFoundation.h"
 #import <Foundation/Foundation.h>
 
-#include <mbgl/util/optional.hpp>
-
 NS_ASSUME_NONNULL_BEGIN
 
 /**
@@ -34,7 +32,9 @@ MGL_EXPORT
  - A boolean value NO to disable client-side rendering of CJK glyphs —
  remote fonts specified in your style will be used instead.
  */
-@property (nonatomic, readonly) mbgl::optional<std::string> localFontFamilyName;
+@property (nonatomic, readonly, nullable) NSString *localFontFamilyName;
+
+- (nullable NSString *)localFontFamilyNameWithInfoDictionaryObject:(nullable id)infoDictionaryObject;
 
 /**
  A Boolean value indicating whether symbol layers may enable per-source symbol
@@ -49,6 +49,8 @@ MGL_EXPORT
  */
 @property (nonatomic, readonly) BOOL perSourceCollisions;
 
+- (BOOL)perSourceCollisionsWithInfoDictionaryObject:(nullable id)infoDictionaryObject;
+
 @end
 
 NS_ASSUME_NONNULL_END

platform/darwin/src/MGLRendererConfiguration.m

@@ -0,0 +1,66 @@
+#import "MGLRendererConfiguration.h"
+
+#if TARGET_OS_IPHONE
+#import <UIKit/UIKit.h>
+#else
+#import <AppKit/AppKit.h>
+#endif
+
+static NSString * const MGLCollisionBehaviorPre4_0Key = @"MGLCollisionBehaviorPre4_0";
+static NSString * const MGLIdeographicFontFamilyNameKey = @"MGLIdeographicFontFamilyName";
+
+@implementation MGLRendererConfiguration
+
++ (instancetype)currentConfiguration {
+    return [[self alloc] init];
+}
+
+- (const float)scaleFactor {
+#if TARGET_OS_IPHONE
+    return [UIScreen instancesRespondToSelector:@selector(nativeScale)] ? [[UIScreen mainScreen] nativeScale] : [[UIScreen mainScreen] scale];
+#else
+    return [NSScreen mainScreen].backingScaleFactor;
+#endif
+}
+
+- (nullable NSString *)localFontFamilyName {
+    id infoDictionaryObject = [NSBundle.mainBundle objectForInfoDictionaryKey:MGLIdeographicFontFamilyNameKey];
+    return [self localFontFamilyNameWithInfoDictionaryObject:infoDictionaryObject];
+}
+
+- (nullable NSString *)localFontFamilyNameWithInfoDictionaryObject:(nullable id)infoDictionaryObject {
+    if ([infoDictionaryObject isKindOfClass:[NSNumber class]] && ![infoDictionaryObject boolValue]) {
+        // NO means don’t use local fonts.
+        return nil;
+    } else if ([infoDictionaryObject isKindOfClass:[NSString class]]) {
+        return infoDictionaryObject;
+    } else if ([infoDictionaryObject isKindOfClass:[NSArray class]]) {
+        // mbgl::LocalGlyphRasterizer::Impl accepts only a single string, but form a cascade list with one font on each line.
+        return [infoDictionaryObject componentsJoinedByString:@"\n"];
+    }
+
+#if TARGET_OS_IPHONE
+    return [UIFont systemFontOfSize:0 weight:UIFontWeightRegular].familyName;
+#else
+    return [NSFont systemFontOfSize:0 weight:NSFontWeightRegular].familyName;
+#endif
+}
+
+- (BOOL)perSourceCollisions {
+    id infoDictionaryObject = [NSBundle.mainBundle objectForInfoDictionaryKey:MGLCollisionBehaviorPre4_0Key];
+    return [self perSourceCollisionsWithInfoDictionaryObject:infoDictionaryObject];
+}
+
+- (BOOL)perSourceCollisionsWithInfoDictionaryObject:(nullable id)infoDictionaryObject {
+    // Set the collision behaviour. A value set in `NSUserDefaults.standardUserDefaults`
+    // should override anything in the application's info.plist
+    if ([NSUserDefaults.standardUserDefaults objectForKey:MGLCollisionBehaviorPre4_0Key]) {
+        return [NSUserDefaults.standardUserDefaults boolForKey:MGLCollisionBehaviorPre4_0Key];
+    } else if ([infoDictionaryObject isKindOfClass:[NSNumber class]] || [infoDictionaryObject isKindOfClass:[NSString class]]) {
+        // Also support NSString to correspond with the behavior of `-[NSUserDefaults boolForKey:]`
+        return [infoDictionaryObject boolValue];
+    }
+    return NO;
+}
+
+@end

platform/darwin/test/MGLMapSnapshotterTests.m

@@ -49,7 +49,7 @@ BOOL MGLEqualImages(MGLImage *leftImage, MGLImage *rightImage) {
 #endif
 }
 
-@interface MGLMapSnapshotterTests : XCTestCase <MGLMapSnapshotterDelegate>
+@interface MGLMapSnapshotterTests : XCTestCase <MGLMapSnapshotterDelegate, MGLOfflineStorageDelegate>
 
 @property (nonatomic) XCTestExpectation *styleLoadingExpectation;
 @property (nonatomic, copy, nullable) void (^runtimeStylingActions)(MGLStyle *style);
@@ -62,10 +62,13 @@ - (void)setUp {
     [super setUp];
 
     [MGLAccountManager setAccessToken:@"pk.feedcafedeadbeefbadebede"];
+
+    [MGLOfflineStorage sharedOfflineStorage].delegate = self;
 }
 
 - (void)tearDown {
     [MGLAccountManager setAccessToken:nil];
+    [MGLOfflineStorage sharedOfflineStorage].delegate = nil;
     self.styleLoadingExpectation = nil;
     self.runtimeStylingActions = nil;
     [super tearDown];
@@ -138,20 +141,26 @@ - (void)testDelegate {
 }
 
 - (void)testRuntimeStyling {
-    [self testRuntimeStylingActions:^(MGLStyle *style) {
+    [self testStyleURL:nil applyingRuntimeStylingActions:^(MGLStyle *style) {
         MGLBackgroundStyleLayer *backgroundLayer = [[MGLBackgroundStyleLayer alloc] initWithIdentifier:@"background"];
         backgroundLayer.backgroundColor = [NSExpression expressionForConstantValue:[MGLColor orangeColor]];
         [style addLayer:backgroundLayer];
     } expectedImageName:@"Fixtures/MGLMapSnapshotterTests/background"];
 }
 
+- (void)testLocalGlyphRendering {
+    [[NSUserDefaults standardUserDefaults] setObject:@[@"PingFang TC"] forKey:@"MGLIdeographicFontFamilyName"];
+    NSURL *styleURL = [[NSBundle bundleForClass:[self class]] URLForResource:@"mixed" withExtension:@"json"];
+    [self testStyleURL:styleURL applyingRuntimeStylingActions:^(MGLStyle *style) {} expectedImageName:@"Fixtures/MGLMapSnapshotterTests/PingFang"];
+}
+
 /**
  Tests that applying the given runtime styling actions on a blank style results in a snapshot image that matches the image with the given name in the asset catalog.
 
  @param actions Runtime styling actions to apply to the blank style.
  @param expectedImageName Name of the test fixture image in Media.xcassets.
  */
-- (void)testRuntimeStylingActions:(void (^)(MGLStyle *style))actions expectedImageName:(NSString *)expectedImageName {
+- (void)testStyleURL:(nullable NSURL *)styleURL applyingRuntimeStylingActions:(void (^)(MGLStyle *style))actions expectedImageName:(NSString *)expectedImageName {
     self.styleLoadingExpectation = [self expectationWithDescription:@"Style should finish loading."];
     XCTestExpectation *overlayExpectation = [self expectationWithDescription:@"Overlay handler should get called."];
     XCTestExpectation *completionExpectation = [self expectationWithDescription:@"Completion handler should get called."];
@@ -163,9 +172,15 @@ - (void)testRuntimeStylingActions:(void (^)(MGLStyle *style))actions expectedIma
 #endif
     XCTAssertNotNil(expectedImage, @"Image fixture “%@” missing from Media.xcassets.", expectedImageName);
 
-    NSURL *styleURL = [[NSBundle bundleForClass:[self class]] URLForResource:@"one-liner" withExtension:@"json"];
+    if (!styleURL) {
+        styleURL = [[NSBundle bundleForClass:[self class]] URLForResource:@"one-liner" withExtension:@"json"];
+    }
     MGLMapCamera *camera = [MGLMapCamera camera];
-    MGLMapSnapshotOptions *options = [[MGLMapSnapshotOptions alloc] initWithStyleURL:styleURL camera:camera size:CGSizeMake(500, 500)];
+    camera.centerCoordinate = kCLLocationCoordinate2DInvalid;
+    camera.heading = -1;
+    camera.pitch = -1;
+    MGLMapSnapshotOptions *options = [[MGLMapSnapshotOptions alloc] initWithStyleURL:styleURL camera:camera size:expectedImage.size];
+    options.zoomLevel = -1;
 
     MGLMapSnapshotter *snapshotter = [[MGLMapSnapshotter alloc] initWithOptions:options];
     snapshotter.delegate = self;
@@ -183,8 +198,8 @@ - (void)testRuntimeStylingActions:(void (^)(MGLStyle *style))actions expectedIma
         XCTAssertNil(error);
         XCTAssertNotNil(snapshot);
         if (snapshot) {
-            XCTAssertEqual(snapshot.image.size.width, 500);
-            XCTAssertEqual(snapshot.image.size.height, 500);
+            XCTAssertEqual(snapshot.image.size.width, expectedImage.size.width);
+            XCTAssertEqual(snapshot.image.size.height, expectedImage.size.height);
         }
         [completionExpectation fulfill];
     }];
@@ -205,4 +220,13 @@ - (void)mapSnapshotter:(MGLMapSnapshotter *)snapshotter didFinishLoadingStyle:(M
     [self.styleLoadingExpectation fulfill];
 }
 
+#pragma mark MGLOfflineStorageDelegate methods
+
+- (NSURL *)offlineStorage:(MGLOfflineStorage *)storage URLForResourceOfKind:(MGLResourceKind)kind withURL:(NSURL *)url {
+    if (kind == MGLResourceKindGlyphs && [url.scheme isEqualToString:@"local"]) {
+        return [[NSBundle bundleForClass:[self class]] URLForResource:@"glyphs" withExtension:@"pbf"];
+    }
+    return url;
+}
+
 @end