feat(dictionary): characters of Chinese, Korean and Greek, written by hand; pinyin typed

Parity with Japanese's kanji and kana:

- The characters' tab is named by its language (Hanzi, Hangul & Hanja,
  Alphabet), its groups too: HSK levels and the characters in common use
  (Hong Kong's grades for traditional ones); Hangul and the Hanja taught
  in schools; Greek's letters. Radicals for Chinese and Korean in their
  own forms (讠 for 言 in simplified Chinese), none for Greek.
- A character's readings are named as its language names them: On and
  Kun, Pinyin, Eum and Hun (음, 훈); a letter means its sound and name.
- How characters are written comes by language: Chinese from Make Me a
  Hanzi (its medians in KanjiVG's square, Arphic Public License, a data
  file beside the app, never in cards), the Hangul letters drawn by the
  curator; a Korean word is written letter by letter (닭: ㄷ ㅏ ㄺ). Words
  of alphabets (German, Greek) aren't written by hand.
- A Chinese word's pinyin is typed in a session, tone numbers turning
  into marks (ni3 → nǐ); KRDict's levels (초급, 중급, 고급) tag Korean
  words; a Korean word's pronunciation shows in brackets ([가치]).
- Smaller: Look up in the composer keeps a noun's article; the Watch
  filter names its level list; hints and placeholders by language.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/test/core/chinese/pinyin_input_test.dart

@@ -0,0 +1,52 @@
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:halkyon_learn_flutter/src/core/chinese/pinyin_input.dart';
+
+void main() {
+  test('tone numbers become tone marks: on a or e, on the o of ou, else on '
+      'the last vowel; ü typed as v or u:; the neutral tone unmarked', () {
+    expect(withToneMarks('ni3hao3'), 'nǐhǎo');
+    expect(withToneMarks('xue2xi2'), 'xuéxí');
+    expect(withToneMarks('dou1'), 'dōu');
+    expect(withToneMarks('gui4'), 'guì');
+    expect(withToneMarks('liu2'), 'liú');
+    expect(withToneMarks('lv4'), 'lǜ');
+    expect(withToneMarks('nu:3'), 'nǚ');
+    expect(withToneMarks('ma5'), 'ma');
+    expect(withToneMarks('Bei3jing1'), 'Běijīng');
+    expect(withToneMarks('xuéxí'), 'xuéxí');
+  });
+
+  test('pinyin compares with its tones, whatever its case, spaces and '
+      'numbers', () {
+    expect(pinyinKey('Xué xí'), 'xuéxí');
+    expect(pinyinKey('xue2 xi2'), 'xuéxí');
+    expect(pinyinKey("Xi1'an1"), 'xīān');
+    expect(givenPinyin('xíng, háng'), {'xíng', 'háng'});
+    expect(givenPinyin('xíng').contains(pinyinKey('xing2')), isTrue);
+    expect(givenPinyin('xíng').contains(pinyinKey('xing1')), isFalse);
+  });
+
+  test("pinyin is told from kana and from words' own letters", () {
+    expect(isPinyin('xué xí'), isTrue);
+    expect(isPinyin('shuō'), isTrue);
+    expect(isPinyin('たべる'), isFalse);
+    expect(isPinyin('가치'), isFalse);
+    expect(isPinyin(''), isFalse);
+  });
+
+  test('typing turns a syllable and its tone into the marked syllable, the '
+      'caret where it was typed', () {
+    const formatter = PinyinInputFormatter();
+    final value = formatter.formatEditUpdate(
+      const TextEditingValue(text: 'ni'),
+      const TextEditingValue(
+        text: 'ni3',
+        selection: TextSelection.collapsed(offset: 3),
+      ),
+    );
+
+    expect(value.text, 'nǐ');
+    expect(value.selection, const TextSelection.collapsed(offset: 2));
+  });
+}

halkyon_learn_flutter/test/feature/dictionary/dictionary_data_test.dart

@@ -91,6 +91,91 @@ void main() {
     });
   });
 
+  group('a character of another language', () {
+    test("Chinese: its pinyin as its readings, its HSK level and Hong Kong's "
+        'grade from its labels', () {
+      final say = DictionaryCharacter.fromEntry(
+        ref: (source: 'unihan-hant', id: '說'),
+        headword: '說',
+        labels: const ['hsk:1', 'common', 'grade:1', 'radical:149'],
+        entry:
+            '{"meanings": ["speak", "say"], "pinyin": ["shuō", "shuì"], '
+            '"strokes": 14, "simplified": ["说"]}',
+        language: 'zh-Hant',
+      );
+
+      expect(say.onReadings, ['shuō', 'shuì']);
+      expect(say.kunReadings, isEmpty);
+      expect((say.hsk, say.grade, say.strokes), (1, 1, 14));
+      expect(say.tagNames, ['HSK-1', 'Grade 1']);
+      expect(say.card.onReadings, ['shuō', 'shuì']);
+    });
+
+    test('Korean: a Hanja its sounds and native meanings, the 1,800 of '
+        'education tagged; a letter its sound and name', () {
+      final water = DictionaryCharacter.fromEntry(
+        ref: (source: 'unihan-ko', id: '水'),
+        headword: '水',
+        labels: const ['education', 'radical:85'],
+        entry:
+            '{"meanings": ["water"], "eum": ["수"], "hun": ["물"], '
+            '"eumhun": ["물 수"], "strokes": 4}',
+        language: 'ko',
+      );
+      expect(water.onReadings, ['수']);
+      expect(water.kunReadings, ['물']);
+      expect(water.isEducationHanja, isTrue);
+      expect(water.tagNames, ['Education Hanja']);
+
+      final giyeok = DictionaryCharacter.fromEntry(
+        ref: (source: 'unihan-ko', id: 'ㄱ'),
+        headword: 'ㄱ',
+        labels: const ['hangul'],
+        entry: '{"romaji": "g, k", "script": "hangul", "name": "기역"}',
+        language: 'ko',
+      );
+      expect(giyeok.isKana, isTrue);
+      expect(giyeok.meaningsShown, ['g, k', '기역']);
+      expect(giyeok.tagNames, ['Hangul']);
+    });
+
+    test('Greek: a letter with its capital, its transliteration and its '
+        'names', () {
+      final beta = DictionaryCharacter.fromEntry(
+        ref: (source: 'greek-alphabet', id: 'β'),
+        headword: 'Β β',
+        labels: const ['greek'],
+        entry:
+            '{"romaji": "v", "script": "greek", "name": "βήτα", '
+            '"englishName": "beta", "sound": "v"}',
+        language: 'el',
+      );
+
+      expect(beta.card.front.plainText.trim(), 'Β β');
+      expect(beta.card.meanings, ['v', 'βήτα (beta)']);
+      expect(beta.tagNames, ['Greek alphabet']);
+      expect(isDictionaryTagName('Greek alphabet'), isTrue);
+    });
+
+    test("a Korean word's KRDict level names its tag as KRDict does", () {
+      final school = DictionaryWord.fromEntry(
+        ref: (source: 'krdict', id: '73276'),
+        headword: '학교',
+        reading: '학꾜',
+        labels: const ['level:beginner'],
+        entry:
+            '{"pos": "noun", "hanja": ["學校"], '
+            '"senses": [{"glosses": ["school"]}]}',
+        language: 'ko',
+      );
+
+      expect(school.koreanLevel, 1);
+      expect(school.tagNames, ['초급', 'Noun']);
+      expect(isDictionaryTagName('초급'), isTrue);
+      expect(school.card.reading, '학꾜');
+    });
+  });
+
   group('Cards behind the dictionary', () {
     late FakeCardGateway cardGateway;
     late CardRepository cards;

halkyon_learn_flutter/test/feature/dictionary/dictionary_screen_test.dart

@@ -72,8 +72,9 @@ void main() {
     await tester.pumpAndSettle();
   }
 
-  /// Opens the studyset [id]: `japanese` (Japanese with English meanings)
-  /// or `german`, on an instance with JMdict ([dictionaries]), at
+  /// Opens the studyset [id]: `japanese` (Japanese with English meanings),
+  /// `german`, `greek` or `chinese`, on an instance with JMdict
+  /// ([dictionaries]), at
   /// [location] (the studyset's screen unless given).
   Future<void> show(
     WidgetTester tester, {
@@ -107,6 +108,28 @@ void main() {
             backLanguage: 'en',
           ),
         ),
+      )
+      ..receiveRemoteChange(
+        'greek',
+        encodeStudysetPayload(
+          StudysetContent(
+            title: 'Greek',
+            description: RichContent.empty(),
+            frontLanguage: 'el',
+            backLanguage: 'en',
+          ),
+        ),
+      )
+      ..receiveRemoteChange(
+        'chinese',
+        encodeStudysetPayload(
+          StudysetContent(
+            title: 'Chinese',
+            description: RichContent.empty(),
+            frontLanguage: 'zh-Hans',
+            backLanguage: 'en',
+          ),
+        ),
       );
     await pumpApp(
       tester,
@@ -259,6 +282,76 @@ void main() {
     expect(made.content.entry, (source: 'kanjidic', id: '食'));
   });
 
+  testWidgets("Greek's letters in a tab of their own, without radicals, "
+      'added whole as character cards', (tester) async {
+    await show(
+      tester,
+      id: 'greek',
+      dictionaries: FakeDictionaryGateway(
+        available: [wiktionaryEl, greekAlphabet],
+        words: [
+          character(
+            'Β β',
+            labels: ['greek'],
+            romaji: 'v',
+            name: 'βήτα (beta)',
+            of: greekAlphabet,
+          ),
+        ],
+      ),
+    );
+    await addMaterial(tester, 'From the dictionary');
+
+    expect(find.text('Radicals'), findsNothing);
+    await tester.tap(find.text('Alphabet'));
+    await settle(tester);
+    expect(find.text('Letters'), findsOneWidget);
+    await tester.tap(find.text('Greek alphabet').hitTestable());
+    await tester.pumpAndSettle();
+    await tester.tap(find.text('Add 1 character'));
+    await tester.pumpAndSettle();
+
+    final made = (await cards.cardsOf('greek')).single;
+    expect(made.content.front.plainText.trim(), 'Β β');
+    expect(made.content.meanings, ['v', 'βήτα (beta)']);
+  });
+
+  testWidgets('Chinese characters by HSK level and in common use, beside '
+      'the radicals in their simplified forms', (tester) async {
+    await show(
+      tester,
+      id: 'chinese',
+      dictionaries: FakeDictionaryGateway(
+        available: [ccCedictHans, unihanHans],
+        words: [
+          character(
+            '说',
+            meanings: ['speak'],
+            on: ['shuō'],
+            labels: ['hsk:1', 'common', 'radical:149'],
+            of: unihanHans,
+          ),
+        ],
+      ),
+    );
+    await addMaterial(tester, 'From the dictionary');
+
+    await tester.tap(find.text('Hanzi'));
+    await settle(tester);
+    expect(find.text('HSK levels'), findsOneWidget);
+    expect(find.text('In common use'), findsOneWidget);
+    expect(find.text('HSK 1'), findsOneWidget);
+    await tester.tap(find.text('Radicals'));
+    await settle(tester);
+    // 言 as simplified Chinese writes it at a character's side.
+    await tester.scrollUntilVisible(
+      find.text('讠'),
+      400,
+      scrollable: find.byType(Scrollable).last,
+    );
+    expect(find.text('讠'), findsOneWidget);
+  });
+
   testWidgets('a character found shows its readings and strokes, and is '
       'added as a card', (tester) async {
     await show(tester, dictionaries: withKanji());

halkyon_learn_flutter/test/feature/kanji/model/hangul_test.dart

@@ -0,0 +1,26 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:halkyon_learn_flutter/src/feature/kanji/model/hangul.dart';
+
+void main() {
+  test('a Hangul syllable is written with its letters: the opening '
+      'consonant, the vowel and the closing one or cluster', () {
+    expect(hangulLetters('가'), ['ㄱ', 'ㅏ']);
+    expect(hangulLetters('닭'), ['ㄷ', 'ㅏ', 'ㄺ']);
+    expect(hangulLetters('쓰'), ['ㅆ', 'ㅡ']);
+    expect(hangulLetters('왜'), ['ㅇ', 'ㅙ']);
+    expect(hangulLetters('힣'), ['ㅎ', 'ㅣ', 'ㅎ']);
+    // What is no syllable stays as it is.
+    expect(hangulLetters('ㄱ'), ['ㄱ']);
+    expect(hangulLetters('食'), ['食']);
+  });
+
+  test('scripts whose strokes are drawn: Han characters, kana, Hangul; '
+      'not the alphabets', () {
+    expect(hasDrawnScript('食べる'), isTrue);
+    expect(hasDrawnScript('学习'), isTrue);
+    expect(hasDrawnScript('학교'), isTrue);
+    expect(hasDrawnScript('ㄱ'), isTrue);
+    expect(hasDrawnScript('das Haus'), isFalse);
+    expect(hasDrawnScript('Β β'), isFalse);
+  });
+}

halkyon_learn_flutter/test/feature/kanji/model/radical_test.dart

@@ -34,4 +34,21 @@ void main() {
   test("a radical's label is the dictionary's", () {
     expect(radicalLabel(85), 'radical:85');
   });
+
+  test('the forms a radical takes in each language: simplified Chinese its '
+      "own, traditional Chinese and Korean without Japanese's own", () {
+    final speech = radicals[148];
+    final dragon = radicals[211];
+    final food = radicals[183];
+    expect(radicalFormsIn(speech, 'zh-Hans'), ['讠']);
+    expect(radicalFormsIn(speech, 'zh-Hant'), isEmpty);
+    expect(radicalFormsIn(dragon, 'ja'), ['竜']);
+    expect(radicalFormsIn(dragon, 'zh'), ['龙']);
+    expect(radicalFormsIn(dragon, 'ko'), isEmpty);
+    // Simplified Chinese writes 食 as 饣 at a character's side, not 飠.
+    expect(radicalFormsIn(food, 'zh-CN'), ['饣']);
+    expect(radicalFormsIn(food, 'zh-TW'), ['飠']);
+    expect(radicalsIn('zh-Hans')[148].variants, ['讠']);
+    expect((hasRadicals('ko'), hasRadicals('el')), (true, false));
+  });
 }

halkyon_learn_flutter/test/feature/kanji/stroke_data_test.dart

@@ -51,6 +51,43 @@ void main() {
       expect(await strokes.strokesOf(''), isNull);
     });
 
+    test("Chinese draws its characters as Make Me a Hanzi does, KanjiVG's "
+        'for what it lacks; Korean its letters with its own strokes', () async {
+      final strokes = StrokeRepository();
+
+      // 说 is simplified Chinese's alone, which KanjiVG doesn't draw.
+      expect(await strokes.strokesOf('说'), isNull);
+      final say = await strokes.strokesOf('说', language: 'zh-Hans');
+      expect(say!.paths, hasLength(9));
+      expect(strokes.read('说', language: 'zh'), say);
+      // 水 is drawn by both, each in its own shapes.
+      expect(
+        (await strokes.strokesOf('水', language: 'zh'))!.paths,
+        isNot((await strokes.strokesOf('水'))!.paths),
+      );
+      // A kana Make Me a Hanzi doesn't draw comes from KanjiVG.
+      expect(await strokes.strokesOf('あ', language: 'zh'), isNotNull);
+      expect(
+        (await strokes.strokesOf('ㄹ', language: 'ko'))!.paths,
+        hasLength(3),
+      );
+      expect(
+        (await strokes.strokesOf('ㄺ', language: 'ko'))!.components,
+        ['ㄹ', 'ㄱ'],
+      );
+      expect(await strokes.strokesOf('ㄹ', language: 'ja'), isNull);
+    });
+
+    test('each set by language: Japanese KanjiVG, Chinese Make Me a Hanzi '
+        'first, Korean its letters first', () {
+      expect(StrokeSet.of(null), [StrokeSet.kanjivg]);
+      expect(StrokeSet.of('zh-Hant'), [
+        StrokeSet.makemeahanzi,
+        StrokeSet.kanjivg,
+      ]);
+      expect(StrokeSet.of('ko').first, StrokeSet.hangul);
+    });
+
     test('the file a character is in: each 256 code points', () {
       expect(strokeFileOf('食'), '098');
       expect(strokeFileOf('あ'), '030');

halkyon_learn_flutter/test/feature/study/bloc/study_session_bloc_test.dart

@@ -773,7 +773,7 @@ void main() {
         'japanese',
         CardContent(
           type: CardType.character,
-          front: text('食'),
+          front: RichContent.plain('食'),
           back: RichContent.empty(),
           meanings: const ['eat'],
         ),
@@ -800,7 +800,12 @@ void main() {
       await withClock(Clock(() => now), () async {
         final bloc = session();
         addTearDown(bloc.close);
-        final kanji = await showing(bloc, '食');
+        final kanji = await until(
+          bloc,
+          (s) =>
+              s is StudySessionStateShowing &&
+              s.card.content.front == RichContent.plain('食'),
+        ) as StudySessionStateShowing;
         expect(kanji.writes, isTrue);
         rate(bloc, Rating.good);
         final word = await until(

halkyon_learn_flutter/test/feature/study/model/card_study_mode_test.dart

@@ -0,0 +1,38 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:halkyon_learn_flutter/src/core/content/rich_content.dart';
+import 'package:halkyon_learn_flutter/src/feature/card/model/card_content.dart';
+import 'package:halkyon_learn_flutter/src/feature/study/model/card_study_mode.dart';
+import 'package:halkyon_learn_flutter/src/feature/study/model/study_options.dart';
+
+void main() {
+  const writing = StudyOptions(writeByHand: true);
+
+  CardContent word(String front) => CardContent(
+    type: CardType.vocabulary,
+    front: RichContent.plain(front),
+    back: RichContent.empty(),
+    meanings: const ['a meaning'],
+  );
+
+  test('written by hand: words and characters of scripts whose strokes are '
+      'drawn, not words of alphabets', () {
+    expect(writtenByHand(word('食べる'), writing), isTrue);
+    expect(writtenByHand(word('学习'), writing), isTrue);
+    expect(writtenByHand(word('학교'), writing), isTrue);
+    expect(writtenByHand(word('das Haus'), writing), isFalse);
+    expect(writtenByHand(word('σπίτι'), writing), isFalse);
+    expect(
+      writtenByHand(
+        CardContent(
+          type: CardType.character,
+          front: RichContent.plain('Β β'),
+          back: RichContent.empty(),
+          meanings: const ['v'],
+        ),
+        writing,
+      ),
+      isFalse,
+    );
+    expect(writtenByHand(word('食べる'), const StudyOptions()), isFalse);
+  });
+}

halkyon_learn_flutter/test/feature/study/widget/study_screen_test.dart

@@ -768,12 +768,13 @@ void main() {
       'japanese',
       CardContent(
         type: CardType.character,
-        front: paragraph('😀'),
+        // A Han character of Unicode's Extension B, which KanjiVG lacks.
+        front: paragraph('𠀀'),
         back: RichContent.empty(),
-        meanings: const ['grin'],
+        meanings: const ['breath'],
       ),
     );
-    await study(tester, strokes: await loadedStrokes(tester, ['😀']));
+    await study(tester, strokes: await loadedStrokes(tester, ['𠀀']));
     await tester.tap(find.text('Show answer'));
     await tester.pumpAndSettle();
     await tester.tap(find.text('Stroke order'));
@@ -875,6 +876,35 @@ void main() {
     expect(find.byType(RatingRow), findsOneWidget);
   });
 
+  testWidgets("a Chinese word's pinyin is typed: tone numbers turn into "
+      'marks, and the tones count', (tester) async {
+    await cards.create(
+      'japanese',
+      CardContent(
+        type: CardType.vocabulary,
+        front: paragraph('学习'),
+        back: RichContent.empty(),
+        reading: 'xué xí',
+        meanings: const ['to learn'],
+      ),
+    );
+    final settings = SettingsRepository(settingsGateway);
+    addTearDown(settings.dispose);
+    await settings.update(
+      (each) => each.withStudy(const StudyOptions(typeReadings: true)),
+    );
+    await study(tester);
+
+    expect(find.text('The pinyin, with tone numbers or marks'), findsOneWidget);
+    await tester.enterText(find.byType(TextField), 'xue2xi2');
+    await tester.pump();
+    expect(find.text('xuéxí'), findsOneWidget);
+    await tester.testTextInput.receiveAction(TextInputAction.done);
+    await tester.pumpAndSettle();
+
+    expect(find.text('Right'), findsOneWidget);
+  });
+
   testWidgets('a reading typed right says so', (tester) async {
     await cards.create(
       'japanese',

halkyon_learn_flutter/test/support/fake_dictionary_gateway.dart

@@ -61,6 +61,82 @@ const wiktionaryDe = Dictionary(
   entryCount: 4,
 );
 
+/// Chinese words of CC-CEDICT in simplified characters.
+const ccCedictHans = Dictionary(
+  source: 'cc-cedict-hans',
+  sourceVersion: '2026-10-14',
+  kind: DictionaryKind.words,
+  language: 'zh-Hans',
+  glossLanguage: 'en',
+  license: 'CC-BY-SA-4.0',
+  credits: [
+    (
+      name: 'CC-CEDICT',
+      by: 'MDBG',
+      license: 'CC-BY-SA-4.0',
+      url: 'https://www.mdbg.net/chinese/dictionary?page=cc-cedict',
+    ),
+  ],
+  entryCount: 0,
+);
+
+/// Chinese characters of Unihan in simplified writing.
+const unihanHans = Dictionary(
+  source: 'unihan-hans',
+  sourceVersion: '18.0.0',
+  kind: DictionaryKind.characters,
+  language: 'zh-Hans',
+  glossLanguage: 'en',
+  license: 'Unicode-3.0',
+  credits: [
+    (
+      name: 'Unihan Database',
+      by: 'Unicode, Inc.',
+      license: 'Unicode-3.0',
+      url: 'https://www.unicode.org/reports/tr38/',
+    ),
+  ],
+  entryCount: 1,
+);
+
+/// Greek words with English meanings from Wiktionary.
+const wiktionaryEl = Dictionary(
+  source: 'wiktionary-el',
+  sourceVersion: '2026-10-03',
+  kind: DictionaryKind.words,
+  language: 'el',
+  glossLanguage: 'en',
+  license: 'CC-BY-SA-4.0',
+  credits: [
+    (
+      name: 'Wiktionary',
+      by: 'Wiktionary contributors',
+      license: 'CC-BY-SA-4.0',
+      url: 'https://en.wiktionary.org/wiki/Wiktionary:Copyrights',
+    ),
+  ],
+  entryCount: 0,
+);
+
+/// The Greek alphabet the curator writes.
+const greekAlphabet = Dictionary(
+  source: 'greek-alphabet',
+  sourceVersion: '1',
+  kind: DictionaryKind.characters,
+  language: 'el',
+  glossLanguage: 'en',
+  license: 'CC0-1.0',
+  credits: [
+    (
+      name: 'Alphabets (Hangul, Greek)',
+      by: 'Halkyon Learn contributors',
+      license: 'CC0-1.0',
+      url: 'https://code.halkyon.app/project-halkyon/halkyon_learn',
+    ),
+  ],
+  entryCount: 1,
+);
+
 /// A German word of Wiktionary: [headword], its part of speech [pos] in
 /// full, meaning [glosses], its [genders] and the [forms] that find it.
 DictionaryWord germanWord(
@@ -104,7 +180,8 @@ DictionaryWord word(
 );
 
 /// A KANJIDIC2 character: [headword] meaning [meanings], read [on] and
-/// [kun], with [labels]; a kana with its [romaji].
+/// [kun], with [labels]; a kana with its [romaji]; or a character [of]
+/// another dictionary of characters.
 DictionaryCharacter character(
   String headword, {
   List<String> meanings = const [],
@@ -112,11 +189,15 @@ DictionaryCharacter character(
   List<String> kun = const [],
   List<String> labels = const [],
   String? romaji,
+  String? name,
   int? grade,
   int? strokes,
   String? version,
+  Dictionary of = kanjidic,
 }) => DictionaryCharacter(
-  ref: (source: 'kanjidic', id: headword),
+  ref: (source: of.source, id: headword),
+  name: name,
+  language: of.language,
   headword: headword,
   labels: labels,
   meanings: meanings,