Revert "fix(arm64-linux): fix CJK font rendering on flutter-elinux (#15324)" (#15377)

This reverts commit c9391fb894.

flutter/lib/common.dart

@@ -598,22 +598,6 @@ class MyTheme {
     }
   }
 
-  /// Applies [fallbacks] as fontFamilyFallback to every text style in both
-  /// themes. Called once at startup on ARM64 Linux after a CJK font has been
-  /// loaded via FontLoader (see flutter/flutter#139293).
-  static void applyFontFallback(List<String> fallbacks) {
-    lightTheme = lightTheme.copyWith(
-      textTheme: lightTheme.textTheme.apply(fontFamilyFallback: fallbacks),
-      primaryTextTheme:
-          lightTheme.primaryTextTheme.apply(fontFamilyFallback: fallbacks),
-    );
-    darkTheme = darkTheme.copyWith(
-      textTheme: darkTheme.textTheme.apply(fontFamilyFallback: fallbacks),
-      primaryTextTheme:
-          darkTheme.primaryTextTheme.apply(fontFamilyFallback: fallbacks),
-    );
-  }
-
   static ThemeMode currentThemeMode() {
     final preference = getThemeModePreference();
     if (preference == ThemeMode.system) {

flutter/lib/main.dart

@@ -29,8 +29,6 @@ import 'mobile/pages/home_page.dart';
 import 'mobile/pages/server_page.dart';
 import 'mobile/widgets/deploy_dialog.dart';
 import 'models/platform_model.dart';
-import 'native/font_manager.dart'
-    if (dart.library.html) 'web/font_manager.dart';
 
 import 'package:flutter_hbb/plugin/handlers.dart'
     if (dart.library.html) 'package:flutter_hbb/web/plugin/handlers.dart';
@@ -39,15 +37,10 @@ import 'package:flutter_hbb/plugin/handlers.dart'
 int? kWindowId;
 WindowType? kWindowType;
 late List<String> kBootArgs;
-bool _cjkFontLoaded = false;
 
 Future<void> main(List<String> args) async {
   earlyAssert();
   WidgetsFlutterBinding.ensureInitialized();
-  _cjkFontLoaded = await loadSystemCJKFonts();
-  if (_cjkFontLoaded) {
-    MyTheme.applyFontFallback([kLinuxCjkFontFamily]);
-  }
 
   debugPrint("launch args: $args");
   kBootArgs = List.from(args);
@@ -390,7 +383,6 @@ void _runApp(
       builder: (context, child) {
         child = _keepScaleBuilder(context, child);
         child = botToastBuilder(context, child);
-        if (_cjkFontLoaded) child = _mergeCjkFallback(context, child);
         return child;
       },
     ),
@@ -541,7 +533,6 @@ class _AppState extends State<App> with WidgetsBindingObserver {
               : (context, child) {
                   child = _keepScaleBuilder(context, child);
                   child = botToastBuilder(context, child);
-                  if (_cjkFontLoaded) child = _mergeCjkFallback(context, child);
                   if ((isDesktop && desktopType == DesktopType.main) ||
                       isWebDesktop) {
                     child = keyListenerBuilder(context, child);
@@ -595,19 +586,6 @@ _registerEventHandler() {
   }
 }
 
-/// Merges the theme's fontFamilyFallback into [DefaultTextStyle] so that
-/// bare [Text] widgets (and those with inherit:true styles) also pick up the
-/// CJK fallback font loaded on ARM64 Linux.
-Widget _mergeCjkFallback(BuildContext context, Widget? child) {
-  final result = child ?? Container();
-  final fallback = Theme.of(context).textTheme.bodyMedium?.fontFamilyFallback;
-  if (fallback == null || fallback.isEmpty) return result;
-  return DefaultTextStyle.merge(
-    style: TextStyle(fontFamilyFallback: fallback),
-    child: result,
-  );
-}
-
 Widget keyListenerBuilder(BuildContext context, Widget? child) {
   return RawKeyboardListener(
     focusNode: FocusNode(),

flutter/lib/native/font_manager.dart

@@ -1,109 +0,0 @@
-import 'dart:ffi' show Abi;
-import 'dart:io';
-import 'dart:typed_data';
-
-import 'package:flutter/foundation.dart';
-import 'package:flutter/services.dart';
-
-/// Font family name registered with [FontLoader] when a system CJK font is
-/// successfully loaded on ARM64 Linux.
-const kLinuxCjkFontFamily = 'SystemCJK';
-
-const _kFontSearchPaths = [
-  // Debian / Ubuntu (noto-fonts / fonts-noto-cjk)
-  '/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc',
-  '/usr/share/fonts/truetype/noto/NotoSansCJK-Regular.ttc',
-  '/usr/share/fonts/opentype/noto/NotoSansCJKsc-Regular.otf',
-  // Fedora / RHEL / Rocky (google-noto-sans-cjk-fonts)
-  '/usr/share/fonts/google-noto-cjk/NotoSansCJK-Regular.ttc',
-  '/usr/share/fonts/google-noto-sans-cjk-fonts/NotoSansCJK-Regular.ttc',
-  // Arch Linux (noto-fonts-cjk)
-  '/usr/share/fonts/noto-cjk/NotoSansCJK-Regular.ttc',
-  '/usr/share/fonts/noto-cjk/NotoSansCJKsc-Regular.otf',
-  // Generic fallback paths
-  '/usr/share/fonts/noto/NotoSansCJK-Regular.ttc',
-  '/usr/share/fonts/noto/NotoSansCJKsc-Regular.otf',
-  // WenQuanYi — commonly pre-installed on CJK-locale systems
-  '/usr/share/fonts/truetype/wqy/wqy-microhei.ttc',
-  '/usr/share/fonts/truetype/wqy/wqy-zenhei.ttc',
-  '/usr/share/fonts/wqy-microhei/wqy-microhei.ttc',
-  '/usr/share/fonts/wqy-zenhei/wqy-zenhei.ttc',
-];
-
-/// Loads a system CJK font on ARM64 Linux into Flutter's font registry via
-/// [FontLoader], working around the missing fontconfig support in the
-/// flutter-elinux engine (https://github.com/flutter/flutter/issues/139293).
-///
-/// Returns true if a CJK font was successfully loaded; false otherwise.
-/// On all other platforms this is a no-op and returns false immediately.
-Future<bool> loadSystemCJKFonts() async {
-  if (Abi.current() != Abi.linuxArm64) return false;
-
-  final path = await _findCjkFontPath();
-  if (path == null) {
-    debugPrint('ARM64 Linux: no CJK font found; CJK text may not render');
-    return false;
-  }
-
-  try {
-    final loader = FontLoader(kLinuxCjkFontFamily);
-    final bytes = await File(path).readAsBytes();
-    loader.addFont(Future.value(ByteData.view(bytes.buffer, bytes.offsetInBytes, bytes.lengthInBytes)));
-    await loader.load();
-    debugPrint('ARM64 Linux: loaded CJK font from $path');
-    return true;
-  } catch (e) {
-    debugPrint('ARM64 Linux: failed to load CJK font: $e');
-    return false;
-  }
-}
-
-Future<String?> _findCjkFontPath() async {
-  // Query fc-list for each CJK script separately.  Fonts present in all three
-  // sets (zh ∩ ja ∩ ko) are true pan-CJK fonts; prefer them so we don't
-  // accidentally pick a Chinese-only font that lacks Japanese kana or Korean
-  // hangul glyphs.  fc-list is a fontconfig CLI tool available on most Linux
-  // systems independent of whether the Flutter engine was built with fontconfig.
-  final byLang = <String, Set<String>>{};
-  for (final lang in const ['zh', 'ja', 'ko']) {
-    final paths = <String>{};
-    try {
-      final r =
-          await Process.run('fc-list', [':lang=$lang', '--format=%{file}\n']);
-      if (r.exitCode == 0) {
-        for (final line in r.stdout.toString().split('\n')) {
-          final p = line.trim();
-          if (p.isNotEmpty && File(p).existsSync()) paths.add(p);
-        }
-      }
-    } catch (e) {
-      debugPrint('ARM64 Linux: fc-list failed for lang=$lang: $e');
-    }
-    byLang[lang] = paths;
-  }
-
-  final panCjk = byLang['zh']!
-      .intersection(byLang['ja']!)
-      .intersection(byLang['ko']!);
-  final anyCjk =
-      byLang.values.fold(<String>{}, (acc, s) => acc..addAll(s));
-
-  // Among candidates, prefer well-known pan-CJK font families.
-  String? pick(Iterable<String> pool) {
-    const preferred = ['notosanscjk', 'sourcehansans', 'sourcehanserif'];
-    for (final name in preferred) {
-      for (final p in pool) {
-        if (p.toLowerCase().contains(name)) return p;
-      }
-    }
-    return pool.isNotEmpty ? pool.first : null;
-  }
-
-  final found = pick(panCjk) ?? pick(anyCjk);
-  if (found != null) return found;
-
-  for (final p in _kFontSearchPaths) {
-    if (File(p).existsSync()) return p;
-  }
-  return null;
-}

flutter/lib/web/font_manager.dart

@@ -1,8 +0,0 @@
-/// Web stub for `native/font_manager.dart`.
-///
-/// The native implementation depends on `dart:io` (Process/File/Platform) to
-/// load a system CJK font on ARM64 Linux, which cannot compile for the web
-/// target. The web build has no such fontconfig limitation, so this is a no-op.
-const kLinuxCjkFontFamily = 'SystemCJK';
-
-Future<bool> loadSystemCJKFonts() async => false;