# halkyon_ui

Halkyon's look, shared by its apps (Learn, Todo, Train): one theme around the
kingfisher's cobalt and copper, the bundled Noto Sans, Material 3's window
sizes, and the widgets every app's screens are built of, with their texts in
British English, American English and German.

Written as the apps are: Dart 3.13's primary constructors, Material from
`package:material_ui` (never `package:flutter/material.dart`), Lucide icons,
LeanCode's lints.

## What it holds

- **Theme** (`lib/src/theme/`): `appTheme(brightness, extensions: …)`, Material
  3 with hand-written light and dark schemes (primary cobalt, tertiary copper,
  cobalt-tinted neutrals), Material 3 Expressive's 64 dp navigation bar, flat
  app bars, floating snack bars; `Brand`; `ThemeExtras`, the status colours
  Material has no role for (`Theme.of(context).extras`); `PaletteColor`, the
  20 colours a person can give content, each with a text colour held to WCAG
  AA by a test; `FittedSnackBars`.
- **Fonts**: Noto Sans for Latin, Greek and Cyrillic, every weight in one
  variable file, as `appFontFamily` (`packages/halkyon_ui/Noto Sans`). Chinese,
  Japanese and Korean fall back to `Noto Sans JP`, `SC`, `TC` and `KR`, which
  an app bundles itself if it needs them (`appFontFallbackFor` puts a
  language's own first).
- **Layout** (`lib/src/layout/`): `WindowSize` (`context.windowSize`) and
  `readableContentMaxWidth`.
- **Widgets** (`lib/src/widget/`): `showAdaptiveSheet` with `SheetScaffold`;
  `TopGradient`, `ScreenTint`, `ScreenColor`, `TintFrame`, `FramedScreen`
  and `TabVisibility`; `FloatingNavigationBar`; `AppLoadingIndicator`,
  `ButtonLoadingIndicator`, `AppRefreshIndicator`; `SectionCard`,
  `SliverCentered`, `EmptyListMessage`, `CountBadge`, `TitleWithKicker`,
  `CollapsingRow`, `ScrollHidingFab`, `liftWhileDragged`, `ReorderToggle`,
  `ReorderGrip`; `ChevronField`, `requiredDecoration`, `FieldInfoButton`,
  `CountStepper`, `PaletteColorPicker`, `TextLimits` with
  `nearLimitCounter`; `confirmDestructiveAction`, `showUndoSnackBar`,
  `showMoreInfoSheet`; `FoundById`; `KeyboardBackOnResume`; `BrandWordmark`
  and `LaunchScreen`, which take the app's word and icon.

What belongs to one app stays in it: its own colours (an extension passed to
`appTheme`), routes, repositories, editors and texts.

## Using it in an app

Depend on it by git, pinned to a signed commit, as the apps pin their forks:

```yaml
dependencies:
  halkyon_ui:
    git:
      url: https://code.halkyon.app/project-halkyon/halkyon_shared.git
      path: packages/halkyon_ui
      ref: <signed commit>
```

While changing both at once, point the app at a local checkout with a
git-ignored `pubspec_overrides.yaml` beside the app's workspace root:

```yaml
dependency_overrides:
  halkyon_ui:
    path: ../halkyon_shared/packages/halkyon_ui
```

The lockfile then records the path: never commit it so, as CI has no such
folder.

Then set the app up as `example/lib/main.dart` does:

```dart
MaterialApp(
  theme: appTheme(Brightness.light, extensions: [MyColors.light]),
  darkTheme: appTheme(Brightness.dark, extensions: [MyColors.dark]),
  localizationsDelegates: const [
    AppLocalizations.delegate,
    HalkyonUiLocalizations.delegate,
    // material_ui's: flutter_localizations' serve only the SDK's Material.
    ...GlobalMaterialLocalizations.delegates,
  ],
  supportedLocales: AppLocalizations.supportedLocales,
  builder: (context, child) => FittedSnackBars(child: child!),
  …
);
```

and call `registerFontLicenses()` at start. An app bundling the CJK fonts
declares them in its own `pubspec.yaml` under exactly the names
`appFontFallback` lists (no `packages/` prefix) and registers their licence
itself.

## Texts

`lib/l10n/halkyon_ui_en.arb` is the template (British English, also the
fallback); `halkyon_ui_de.arb` German, informal "du"; `halkyon_ui_en_US.arb`
only what American English spells differently; `halkyon_ui_en_GB.arb` empty. A
new text goes into the template and German together (`test/l10n/` fails
otherwise). `flutter pub get` writes `lib/l10n/halkyon_ui_localizations*.dart`,
which are committed (apps take the package by git) and never edited or
formatted by hand.

## Checks

From the workspace root: `dart analyze --fatal-infos`; then `flutter test` in
`packages/halkyon_ui` and in `packages/halkyon_ui/example`, whose tests check
what only an app sees (the font under the name an app finds it by, its
licence).