Halkyon's shared packages

A pub workspace of the Dart packages Halkyon's apps share: halkyon_ui,
Halkyon's look (the theme, fonts, layout and shared widgets, with texts
in English and German), halkyon_core's low-level primitives and
halkyon_interop's cross-app contracts. Dart 3.13 with LeanCode's lints,
configured once at the root; apps take a package by git, pinned to a
signed commit.

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

packages/halkyon_ui/test/theme/app_fonts_test.dart

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+import 'dart:ui' as ui;
+
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:halkyon_ui/halkyon_ui.dart';
+import 'package:material_ui/material_ui.dart';
+
+/// How many pixels [text] inks in [family] at [weight]: heavier strokes ink
+/// more.
+Future<int> ink(String text, String family, FontWeight weight) async {
+  final painter = TextPainter(
+    text: TextSpan(
+      text: text,
+      style: TextStyle(
+        fontFamily: family,
+        fontSize: 40,
+        fontWeight: weight,
+        color: const Color(0xFF000000),
+      ),
+    ),
+    textDirection: TextDirection.ltr,
+  )..layout();
+  final recorder = ui.PictureRecorder();
+  painter.paint(Canvas(recorder), Offset.zero);
+  final image = await recorder.endRecording().toImage(
+    painter.width.ceil(),
+    painter.height.ceil(),
+  );
+  final pixels = (await image.toByteData())!;
+  var inked = 0;
+  for (var alpha = 3; alpha < pixels.lengthInBytes; alpha += 4) {
+    if (pixels.getUint8(alpha) > 128) {
+      inked++;
+    }
+  }
+  return inked;
+}
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  test("the font is the package's own, as an app finds a package's font", () {
+    expect(appFontFamily, 'packages/halkyon_ui/Noto Sans');
+  });
+
+  test("the theme sets text in Noto Sans, with the apps' CJK fonts for what "
+      'it lacks, named as an app declares them', () {
+    for (final brightness in Brightness.values) {
+      final style = appTheme(brightness).textTheme.bodyLarge!;
+      expect(style.fontFamily, appFontFamily);
+      expect(style.fontFamilyFallback, [
+        'Noto Sans JP',
+        'Noto Sans SC',
+        'Noto Sans TC',
+        'Noto Sans KR',
+      ]);
+    }
+  });
+
+  test("a language's own CJK font comes first, so shared Han characters "
+      'take its shapes', () {
+    expect(appFontFallbackFor(null).first, 'Noto Sans JP');
+    expect(appFontFallbackFor('en'), appFontFallback);
+    expect(appFontFallbackFor('ja').first, 'Noto Sans JP');
+    expect(appFontFallbackFor('zh-Hans').first, 'Noto Sans SC');
+    expect(appFontFallbackFor('zh').first, 'Noto Sans SC');
+    expect(appFontFallbackFor('zh-Hant').first, 'Noto Sans TC');
+    expect(appFontFallbackFor('zh-TW').first, 'Noto Sans TC');
+    expect(appFontFallbackFor('ko').first, 'Noto Sans KR');
+    expect(hasOwnFont('ko'), isTrue);
+    expect(hasOwnFont('de'), isFalse);
+    // Every font stays, once.
+    expect(appFontFallbackFor('ko').toSet(), appFontFallback.toSet());
+    expect(appFontFallbackFor('ko'), hasLength(4));
+  });
+
+  test('Noto Sans draws every weight from its one file', () async {
+    // In this package's own tests it is the root project, whose assets have
+    // no `packages/` prefix; an app's test of the name is in example/.
+    final loader = FontLoader(appFontFamily)
+      ..addFont(rootBundle.load('assets/fonts/NotoSans-Variable.ttf'));
+    await loader.load();
+
+    const text = 'Ἀθῆναι Halkyon';
+    final regular = await ink(text, appFontFamily, FontWeight.w400);
+    final bold = await ink(text, appFontFamily, FontWeight.w700);
+    expect(bold, greaterThan(regular * 1.2));
+  });
+}