[ios, macos] Default to local rendering of CJK characters, using system font

platform/darwin/src/MGLRendererConfiguration.h

@@ -26,11 +26,19 @@ MGL_EXPORT
 /** The name of the font family to use for client-side text rendering.
 
  Currently only used for CJK glyphs. Changing this at run time is not currently
- supported. Enable client-side rendering of CJK glyphs by setting
- `MGLIdeographicFontFamilyName` in your containing app's Info.plist to a value
- which will be available at run time. Default font for local ideograph font family
- is "PingFang". */
-@property (nonatomic, readonly) std::string localFontFamilyName;
+ supported. By default, client-side rendering is enabled for CJK glyphs using Apple
+ system default font.
+
+ Set `MGLIdeographicFontFamilyName` in your containing app's Info.plist to a string
+ value which will be available at run time, e.g. "PingFang TC".
+
+ Set `MGLIdeographicFontFamilyName` in your containing app's Info.plist to a array of
+ font family names. Once the front ones are unavaiable, it will fallback to others until
+ using default system font.
+
+ Set `MGLIdeographicFontFamilyName` to `NULL` for using your custom remote font.
+ */
+@property (nonatomic, readonly) mbgl::optional<std::string> localFontFamilyName;
 
 /**
  A Boolean value indicating whether symbol layers may enable per-source symbol

platform/darwin/src/MGLRendererConfiguration.mm

@@ -69,10 +69,38 @@ - (const float)scaleFactor {
     return mbgl::optional<std::string>();
 }
 
-- (std::string)localFontFamilyName {
-    NSString *fontFamilyName = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"MGLIdeographicFontFamilyName"];
+- (mbgl::optional<std::string>)localFontFamilyName {
+
+    std::string systemFontFamilyName;
+#if TARGET_OS_IPHONE
+    systemFontFamilyName = std::string([[UIFont systemFontOfSize:0 weight:UIFontWeightRegular].familyName UTF8String]);
+#else
+    systemFontFamilyName = std::string([[NSFont systemFontOfSize:0 weight:NSFontWeightRegular].familyName UTF8String]);
+#endif
 
-    return fontFamilyName ? std::string([fontFamilyName UTF8String]) : std::string("PingFang");
+    id fontFamilyName = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"MGLIdeographicFontFamilyName"];
+    if([fontFamilyName isKindOfClass:[NSString class]])
+    {
+        if([fontFamilyName isEqualToString:@"NULL"]){
+            return mbgl::optional<std::string>();
+        }
+        return fontFamilyName ? std::string([fontFamilyName UTF8String]) : systemFontFamilyName;
+    }
+    //Ability to specify an array of fonts for fallbacks for `localIdeographicFontFamily`
+    else if ([fontFamilyName isKindOfClass:[NSArray class]]){
+        for(NSString *name in fontFamilyName){
+#if TARGET_OS_IPHONE
+            if([[UIFont familyNames] containsObject:name]){
+                return std::string([name UTF8String]);
+            }
+#else
+            if([[[NSFontManager sharedFontManager] availableFontFamilies] containsObject:name]){
+                return std::string([name UTF8String]);
+            }
+#endif
+        }
+    }
+    return systemFontFamilyName;
 }
 
 @end

platform/ios/CHANGELOG.md

@@ -5,6 +5,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 ## master
 
 * Fixed a crash caused by incorrect `MGLMapViewImpl` renderable size. ([#14810](https://github.com/mapbox/mapbox-gl-native/pull/14810))
+* Fixed an issue that caused the map to ignore the remote fonts for CJK Kanji glyphs. Added ability to specify an array of fonts for fallbacks for local ideographic font family.([#14862](https://github.com/mapbox/mapbox-gl-native/pull/14862))
 * Fixed queryRenderedFeatues bug caused by incorrect sort feature index calculation. ([#14884](https://github.com/mapbox/mapbox-gl-native/pull/14884))
 
 ## 5.1.0

platform/ios/app/Info.plist

@@ -25,7 +25,7 @@
 	<key>LSRequiresIPhoneOS</key>
 	<true/>
 	<key>MGLIdeographicFontFamilyName</key>
-	<string>PingFang TC</string>
+	<string>Helvetica</string>
 	<key>NSHumanReadableCopyright</key>
 	<string>© 2014–2019 Mapbox</string>
 	<key>NSLocationAlwaysUsageDescription</key>