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/example/.gitignore

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+# Flutter/Dart/Pub related
+.dart_tool/
+build/

packages/halkyon_ui/example/analysis_options.yaml

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+# The workspace's lint rules (see ../../../analysis_options.yaml).
+include: ../../../analysis_options.yaml
+
+analyzer:
+  exclude:
+    - build/**
+
+formatter:
+  trailing_commas: preserve

packages/halkyon_ui/example/lib/main.dart

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+import 'package:halkyon_ui/halkyon_ui.dart';
+import 'package:material_ui/material_ui.dart';
+
+void main() {
+  registerFontLicenses();
+  runApp(const ExampleApp());
+}
+
+/// An app set up as Halkyon's are: the shared theme in both brightnesses,
+/// the package's texts beside Material's (from material_ui, whose own
+/// delegates serve its widgets), and snack bars fitted to the window.
+class const ExampleApp({
+  /// The language, the device's when null.
+  final Locale? locale,
+  super.key,
+}) extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) => MaterialApp(
+    title: 'Halkyon Example',
+    theme: appTheme(Brightness.light),
+    darkTheme: appTheme(Brightness.dark),
+    locale: locale,
+    localizationsDelegates: const [
+      HalkyonUiLocalizations.delegate,
+      ...GlobalMaterialLocalizations.delegates,
+    ],
+    supportedLocales: HalkyonUiLocalizations.supportedLocales,
+    builder: (context, child) => FittedSnackBars(child: child!),
+    home: const _Home(),
+  );
+}
+
+class const _Home() extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    final scheme = Theme.of(context).colorScheme;
+    return TopGradient(
+      background: scheme.surface,
+      child: Scaffold(
+        backgroundColor: Colors.transparent,
+        appBar: AppBar(backgroundColor: Colors.transparent),
+        body: Center(
+          child: ConstrainedBox(
+            constraints: const BoxConstraints(
+              maxWidth: readableContentMaxWidth,
+            ),
+            child: Padding(
+              padding: const EdgeInsets.all(16),
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
+                children: [
+                  const BrandWordmark(product: 'Example'),
+                  const SizedBox(height: 24),
+                  SectionCard(
+                    child: Builder(
+                      builder: (context) => FilledButton.tonal(
+                        onPressed: () => confirmDestructiveAction(
+                          context,
+                          title: 'Delete everything?',
+                          message: 'It can’t be undone.',
+                          confirmLabel: 'Delete',
+                        ),
+                        child: const Text('Delete'),
+                      ),
+                    ),
+                  ),
+                ],
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}

packages/halkyon_ui/example/pubspec.yaml

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+name: halkyon_ui_example
+description: "An app built on halkyon_ui, as Halkyon's apps are: shows how one sets it up, and checks what only an app can see (the package's font by the name an app finds it under, its licence)."
+publish_to: none
+resolution: workspace
+
+environment:
+  sdk: ^3.13.0
+  flutter: ^3.44.4
+
+dependencies:
+  flutter:
+    sdk: flutter
+  halkyon_ui: ^0.1.0
+  material_ui: ^1.5.0
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter

packages/halkyon_ui/example/test/example_app_test.dart

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+import 'dart:convert';
+import 'dart:ui' as ui;
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:halkyon_ui/halkyon_ui.dart';
+import 'package:halkyon_ui_example/main.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("an app finds the package's Noto Sans under the theme's name, and "
+      'draws every weight with it', () async {
+    final manifest = jsonDecode(
+      await rootBundle.loadString('FontManifest.json'),
+    ) as List<Object?>;
+    final noto = manifest.cast<Map<String, Object?>>().singleWhere(
+      (font) => font['family'] == appFontFamily,
+    );
+    final assets = [
+      for (final font
+          in (noto['fonts']! as List<Object?>).cast<Map<String, Object?>>())
+        font['asset']! as String,
+    ];
+    expect(
+      assets,
+      contains('packages/halkyon_ui/assets/fonts/NotoSans-Variable.ttf'),
+    );
+
+    // Loaded as the engine loads an app's fonts as it starts: by the
+    // manifest's family and files.
+    final loader = FontLoader(appFontFamily);
+    for (final asset in assets) {
+      loader.addFont(rootBundle.load(asset));
+    }
+    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));
+  });
+
+  test("Noto Sans's licence joins the app's licence list", () async {
+    registerFontLicenses();
+
+    final notices = [
+      await for (final entry in LicenseRegistry.licenses)
+        if (entry.packages.contains('Noto Sans')) entry,
+    ];
+    expect(notices, hasLength(1));
+    expect(
+      notices.single.paragraphs.map((paragraph) => paragraph.text).join(),
+      contains('SIL OPEN FONT LICENSE'),
+    );
+  });
+
+  testWidgets("the app speaks German with the package's texts", (tester) async {
+    await tester.pumpWidget(const ExampleApp(locale: Locale('de')));
+
+    expect(find.text('Halkyon'), findsOneWidget);
+    expect(find.text('Example'), findsOneWidget);
+    await tester.tap(find.text('Delete'));
+    await tester.pumpAndSettle();
+    expect(find.text('Abbrechen'), findsOneWidget);
+  });
+}