Dash: DIN 1451 opt-in per widget (hudFont), GNSS compass, rei by default; widget catalogue

From smart-serow: the DIN 1451 face (Alte DIN 1451 Mittelschrift, via gps-speedo)
and GpsCompass. A cosmetic font is opt-in: widgets name hudFont in their own
TextStyle, the rest keeps the basic font (CJK). Boxes and telltales shrink long
labels instead of wrapping. Telltale and Reading get their own files;
lib/README.md catalogues folders and widgets like smart-serow's.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

lib/README.md

@@ -0,0 +1,34 @@
+---
+type: reference
+---
+# The app's code: a catalogue
+
+Laid out like smart-serow's HUD (`pi/ui/lib/`), which several pieces come from.
+
+## Folders
+
+| Where | Holds |
+|---|---|
+| `lib/*.dart` | Pages (`dash`, `checklist`, `camview`, `linktest`), the boundary client (`boundary`), the USB network binding (`net`), and `reading`, one signal's state as a display needs it |
+| `theme/` | `palette.dart`: the palette and `hudFont` |
+| `widgets/` | Reusable display widgets, one per file, each fed values, never the boundary |
+
+## Widgets
+
+| Widget | File | Shows | From |
+|---|---|---|---|
+| `StatBox`, `StatBoxMain` | `widgets/stat_box.dart` | A value, its unit and label, sized from its box's height; highlight on warning, subdued when dim | smart-serow |
+| `Telltale` | `widgets/telltale.dart` | An on/off lamp: a label or an icon, lit or dark, "—" when missing | Yukart |
+| `WhiskeyMark` | `widgets/whiskey_mark.dart` | Attitude: a horizon tilting with roll, ladder moving with pitch | smart-serow |
+| `AccelGraph` | `widgets/accel_graph.dart` | G-meter: a dot for lateral/longitudinal g, a trace and a peak marker over a window | smart-serow |
+| `GpsCompass` | `widgets/gps_compass.dart` | Heading arrow and bearing; "ACQ" while acquiring, "N/A" without | smart-serow, from gps-speedo |
+
+## Conventions
+
+- **The boxed pattern.** A widget takes its share of a row and sizes its type from its own height, so a layout
+  is a grid of boxes and a value gaining a digit never moves anything. Labels shrink to fit, never wrap.
+- **Colours by meaning.** `AppTheme.of(context)` gives the palette's `background`, `foreground`, `highlight` and
+  `subdued`; no widget names a colour. Themes are smart-serow's JSON (`assets/themes/`), `rei` by default.
+- **Cosmetic fonts are opt-in.** A widget that wants the HUD face names `fontFamily: hudFont` in its own
+  `TextStyle`; everything else keeps the basic font, which covers CJK where DIN 1451 does not.
+- **Missing is a state** (app guideline 2): a widget given no value draws "—" or subdued, never an error.

lib/dash.dart

@@ -6,35 +6,14 @@
 import 'package:flutter/material.dart';
 
 import 'boundary.dart';
+import 'reading.dart';
 import 'theme/palette.dart';
 import 'widgets/accel_graph.dart';
+import 'widgets/gps_compass.dart';
 import 'widgets/stat_box.dart';
+import 'widgets/telltale.dart';
 import 'widgets/whiskey_mark.dart';
 
-/// One signal's current state, as the dash needs it.
-class Reading {
-  const Reading(this.value, {this.dim = false});
-
-  /// The value, or null when missing or known-without-value.
-  final Object? value;
-
-  /// Missing or stale: drawn in subdued.
-  final bool dim;
-
-  static Reading of(Boundary b, String name) {
-    final e = b.signals[name];
-    if (e is! Map) return const Reading(null, dim: true);
-    final q = e['quality'] as String? ?? 'ok';
-    return Reading(e['value'], dim: q != 'ok' || e['value'] == null);
-  }
-
-  double? get number => value is num ? (value as num).toDouble() : null;
-  bool get on => value == true;
-
-  String fixed([int decimals = 0]) =>
-      number == null ? '—' : number!.toStringAsFixed(decimals);
-}
-
 class DashPage extends StatelessWidget {
   const DashPage({super.key, required this.boundary, required this.themes});
   final Boundary boundary;
@@ -54,6 +33,13 @@ class DashPage extends StatelessWidget {
         final coolant = r('obd_coolant_temp_c');
         final lat = r('imu_accel_lat_g');
         final lon = r('imu_accel_lon_g');
+        // The compass's states, from gnss_fix: none → acquiring, 2d/3d → fix, missing → none known.
+        final fix = r('gnss_fix');
+        final gpsState = fix.value == null
+            ? null
+            : fix.value == 'none'
+            ? 'acquiring'
+            : 'fix';
 
         return Scaffold(
           backgroundColor: p.background,
@@ -139,6 +125,12 @@ class DashPage extends StatelessWidget {
                                 dim: coolant.dim,
                                 isWarning: () => (coolant.number ?? 0) > 105,
                               ),
+                              Expanded(
+                                child: GpsCompass(
+                                  heading: r('gnss_heading_deg').number,
+                                  gpsState: gpsState,
+                                ),
+                              ),
                               Telltale(
                                 label: 'LEFT',
                                 icon: Icons.arrow_left,
@@ -183,66 +175,6 @@ class DashPage extends StatelessWidget {
   }
 }
 
-/// An on/off lamp in the boxed pattern: the label is the lamp. Lit in foreground
-/// (highlight when [warn]), dark in subdued; missing shows as a dash.
-class Telltale extends StatelessWidget {
-  const Telltale({
-    super.key,
-    required this.label,
-    required this.reading,
-    this.icon,
-    this.warn = false,
-    this.flex = 1,
-  });
-
-  final String label;
-
-  /// Drawn instead of the label when set. Glyphs like ◀ ▶ come out as emoji on Android.
-  final IconData? icon;
-  final Reading reading;
-  final bool warn;
-  final int flex;
-
-  @override
-  Widget build(BuildContext context) {
-    final p = AppTheme.of(context);
-    final missing = reading.value == null;
-    final lit = reading.on && !reading.dim;
-    final color = lit
-        ? (warn ? p.highlight : p.foreground)
-        : p.subdued.withValues(alpha: missing ? 0.35 : 0.6);
-    return Expanded(
-      flex: flex,
-      child: LayoutBuilder(
-        builder: (context, c) {
-          final size = c.maxHeight * 0.3;
-          if (icon != null && !missing) {
-            return Center(
-              child: Icon(
-                icon,
-                size: c.maxHeight * 0.7,
-                color: color,
-                semanticLabel: label,
-              ),
-            );
-          }
-          return Center(
-            child: Text(
-              missing ? '—' : label,
-              style: TextStyle(
-                fontSize: size,
-                fontWeight: lit ? FontWeight.w700 : FontWeight.w400,
-                color: color,
-                letterSpacing: 1,
-              ),
-            ),
-          );
-        },
-      ),
-    );
-  }
-}
-
 /// The dash's own thin top line: link state, back, and the dark/bright switch.
 class _DashBar extends StatelessWidget {
   const _DashBar({required this.boundary, required this.themes});

lib/reading.dart

@@ -0,0 +1,28 @@
+// One signal's current state as a display needs it: value, and whether to draw it dim
+// (missing, stale or known-without-value; app guideline 2).
+
+import 'boundary.dart';
+
+/// One signal's current state, as the dash needs it.
+class Reading {
+  const Reading(this.value, {this.dim = false});
+
+  /// The value, or null when missing or known-without-value.
+  final Object? value;
+
+  /// Missing or stale: drawn in subdued.
+  final bool dim;
+
+  static Reading of(Boundary b, String name) {
+    final e = b.signals[name];
+    if (e is! Map) return const Reading(null, dim: true);
+    final q = e['quality'] as String? ?? 'ok';
+    return Reading(e['value'], dim: q != 'ok' || e['value'] == null);
+  }
+
+  double? get number => value is num ? (value as num).toDouble() : null;
+  bool get on => value == true;
+
+  String fixed([int decimals = 0]) =>
+      number == null ? '—' : number!.toStringAsFixed(decimals);
+}

lib/theme/palette.dart

@@ -6,17 +6,18 @@
 //   final p = AppTheme.of(context);
 //   color: p.foreground
 //
-// Pick the theme at build time: `--dart-define=YUKART_THEME=rei` (default: default).
+// Pick the theme at build time: `--dart-define=YUKART_THEME=default` (default: rei, smart-serow's).
 
 import 'dart:convert';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 
-const themeName = String.fromEnvironment(
+/// The HUD face (smart-serow's DIN 1451). Opt-in: a widget names it in its own
-  'YUKART_THEME',
+/// TextStyle; everything else keeps the basic font, which covers CJK where DIN does not.
-  defaultValue: 'default',
+const hudFont = 'DIN1451';
-);
+
+const themeName = String.fromEnvironment('YUKART_THEME', defaultValue: 'rei');
 
 /// One variant (dark or bright) of a theme.
 class Palette {

lib/widgets/accel_graph.dart

@@ -126,6 +126,7 @@ class _AccelGraphState extends State<AccelGraph> {
                 Text(
                   'Lon: ${_formatAccel(widget.ay)} (${_formatAccel(_ghostAy)})',
                   style: TextStyle(
+                    fontFamily: hudFont,
                     fontSize: fontSize * 0.5,
                     fontWeight: FontWeight.w400,
                     fontFeatures: const [FontFeature.tabularFigures()],
@@ -136,6 +137,7 @@ class _AccelGraphState extends State<AccelGraph> {
                 Text(
                   'Lat: ${_formatAccel(widget.ax)} (${_formatAccel(_ghostAx)})',
                   style: TextStyle(
+                    fontFamily: hudFont,
                     fontSize: fontSize * 0.5,
                     fontWeight: FontWeight.w400,
                     fontFeatures: const [FontFeature.tabularFigures()],
@@ -149,6 +151,7 @@ class _AccelGraphState extends State<AccelGraph> {
             Text(
               'Acceleration',
               style: TextStyle(
+                fontFamily: hudFont,
                 fontSize: fontSize * 0.8,
                 fontWeight: FontWeight.w400,
                 color: theme.subdued,

lib/widgets/gps_compass.dart

@@ -0,0 +1,94 @@
+// Ported from smart-serow (pi/ui/lib/widgets/gps_compass.dart), itself from android-stuff/gps-speedo:
+// a heading arrow and its bearing. Changes: the palette import and lint fixes.
+
+import 'dart:math' as math;
+
+import 'package:flutter/material.dart';
+
+import '../theme/palette.dart';
+
+class GpsCompass extends StatelessWidget {
+  final double? heading;
+  final String? gpsState; // "acquiring", "fix", "lost"
+
+  const GpsCompass({super.key, this.heading, this.gpsState});
+
+  bool get _hasSignal => heading != null;
+  bool get _isAcquiring => gpsState == 'acquiring';
+
+  String get _displayHeading {
+    if (!_hasSignal) return 'N/A';
+    return '${(heading! % 360).round()}';
+  }
+
+  String get _compassDirection {
+    if (!_hasSignal) return '';
+    final directions = [
+      'N',
+      'NNE',
+      'NE',
+      'ENE',
+      'E',
+      'ESE',
+      'SE',
+      'SSE',
+      'S',
+      'SSW',
+      'SW',
+      'WSW',
+      'W',
+      'WNW',
+      'NW',
+      'NNW',
+    ];
+    final index = ((heading! % 360) / 22.5).round() % 16;
+    return directions[index];
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = AppTheme.of(context);
+
+    // No signal = subdued color, valid = foreground
+    final iconColour = _hasSignal ? theme.foreground : theme.highlight;
+
+    // Convert to radians, 0 = no rotation when no signal
+    final angle = _hasSignal ? (heading! * math.pi / 180.0) : 0.0;
+
+    return Column(
+      mainAxisAlignment: MainAxisAlignment.center,
+      children: [
+        Flexible(
+          flex: 3,
+          child: Transform.rotate(
+            angle: _hasSignal ? angle : 0,
+            child: FittedBox(
+              fit: BoxFit.contain,
+              child: Icon(
+                _hasSignal ? Icons.navigation : Icons.navigation_outlined,
+                size: 120,
+                color: iconColour,
+              ),
+            ),
+          ),
+        ),
+        Flexible(
+          flex: 1,
+          child: FittedBox(
+            fit: BoxFit.contain,
+            child: Text(
+              _hasSignal
+                  ? "$_displayHeading $_compassDirection"
+                  : (_isAcquiring ? "ACQ" : "N/A"),
+              style: TextStyle(
+                fontSize: 80,
+                color: theme.subdued, // less emphasis on text, let the icon have semantic colour
+                fontFamily: hudFont,
+              ),
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+}

lib/widgets/stat_box.dart

@@ -50,7 +50,12 @@ class StatBox extends StatelessWidget {
         builder: (context, constraints) {
           final baseSize = constraints.maxHeight * 0.4;
 
-          return Column(
+          // Shrinks (never wraps) when a label is wider than its box.
+          return Center(
+            child: FittedBox(
+              fit: BoxFit.scaleDown,
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
                 mainAxisAlignment: MainAxisAlignment.center,
                 children: [
                   // Value + optional unit
@@ -62,6 +67,7 @@ class StatBox extends StatelessWidget {
                       Text(
                         value,
                         style: TextStyle(
+                          fontFamily: hudFont,
                           fontSize: baseSize,
                           fontWeight: FontWeight.w400,
                           fontFeatures: const [FontFeature.tabularFigures()],
@@ -75,6 +81,7 @@ class StatBox extends StatelessWidget {
                         Text(
                           unit!,
                           style: TextStyle(
+                            fontFamily: hudFont,
                             fontSize: baseSize * 0.5,
                             fontWeight: FontWeight.w400,
                             color: theme.subdued,
@@ -89,6 +96,7 @@ class StatBox extends StatelessWidget {
                   Text(
                     label,
                     style: TextStyle(
+                      fontFamily: hudFont,
                       fontSize: baseSize * 0.6,
                       fontWeight: FontWeight.w400,
                       color: theme.subdued,
@@ -96,6 +104,8 @@ class StatBox extends StatelessWidget {
                     ),
                   ),
                 ],
+              ),
+            ),
           );
         },
       ),
@@ -134,7 +144,12 @@ class StatBoxMain extends StatelessWidget {
           // Scale fonts relative to box height for consistent proportions
           final baseSize = constraints.maxHeight * 0.4;
 
-          return Column(
+          // Shrinks (never wraps) when a label is wider than its box.
+          return Center(
+            child: FittedBox(
+              fit: BoxFit.scaleDown,
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
                 mainAxisAlignment: MainAxisAlignment.center,
                 children: [
                   // Value + optional unit row
@@ -146,6 +161,7 @@ class StatBoxMain extends StatelessWidget {
                       Text(
                         value,
                         style: TextStyle(
+                          fontFamily: hudFont,
                           fontSize: baseSize,
                           fontWeight: FontWeight.w300,
                           fontFeatures: const [FontFeature.tabularFigures()],
@@ -162,6 +178,7 @@ class StatBoxMain extends StatelessWidget {
                         Text(
                           unit!,
                           style: TextStyle(
+                            fontFamily: hudFont,
                             fontSize: baseSize * 0.4,
                             fontWeight: FontWeight.w400,
                             color: theme.subdued,
@@ -176,6 +193,7 @@ class StatBoxMain extends StatelessWidget {
                   Text(
                     label,
                     style: TextStyle(
+                      fontFamily: hudFont,
                       fontSize: baseSize * 0.35,
                       fontWeight: FontWeight.w400,
                       color: theme.subdued,
@@ -183,6 +201,8 @@ class StatBoxMain extends StatelessWidget {
                     ),
                   ),
                 ],
+              ),
+            ),
           );
         },
       ),

lib/widgets/telltale.dart

@@ -0,0 +1,72 @@
+// An on/off lamp in the boxed pattern (lib/widgets/stat_box.dart): the label is the
+// lamp. Takes a [Reading] (lib/reading.dart) so missing and stale draw as they do elsewhere.
+
+import 'package:flutter/material.dart';
+
+import '../reading.dart';
+import '../theme/palette.dart';
+
+/// An on/off lamp in the boxed pattern: the label is the lamp. Lit in foreground
+/// (highlight when [warn]), dark in subdued; missing shows as a dash.
+class Telltale extends StatelessWidget {
+  const Telltale({
+    super.key,
+    required this.label,
+    required this.reading,
+    this.icon,
+    this.warn = false,
+    this.flex = 1,
+  });
+
+  final String label;
+
+  /// Drawn instead of the label when set. Glyphs like ◀ ▶ come out as emoji on Android.
+  final IconData? icon;
+  final Reading reading;
+  final bool warn;
+  final int flex;
+
+  @override
+  Widget build(BuildContext context) {
+    final p = AppTheme.of(context);
+    final missing = reading.value == null;
+    final lit = reading.on && !reading.dim;
+    final color = lit
+        ? (warn ? p.highlight : p.foreground)
+        : p.subdued.withValues(alpha: missing ? 0.35 : 0.6);
+    return Expanded(
+      flex: flex,
+      child: LayoutBuilder(
+        builder: (context, c) {
+          final size = c.maxHeight * 0.3;
+          if (icon != null && !missing) {
+            return Center(
+              child: Icon(
+                icon,
+                size: c.maxHeight * 0.7,
+                color: color,
+                semanticLabel: label,
+              ),
+            );
+          }
+          return Center(
+            child: FittedBox(
+              fit: BoxFit.scaleDown,
+              child: Text(
+                missing ? '—' : label,
+                maxLines: 1,
+                style: TextStyle(
+                  fontFamily: hudFont,
+                  fontSize: size,
+                  fontWeight: lit ? FontWeight.w700 : FontWeight.w400,
+                  color: color,
+                  letterSpacing: 1,
+                ),
+              ),
+            ),
+          );
+        },
+      ),
+    );
+  }
+}

lib/widgets/whiskey_mark.dart

@@ -64,6 +64,7 @@ class WhiskeyMark extends StatelessWidget {
                 Text(
                   'Roll: ${_formatAngle(roll)}',
                   style: TextStyle(
+                    fontFamily: hudFont,
                     fontSize: fontSize * 0.5,
                     fontWeight: FontWeight.w400,
                     fontFeatures: const [FontFeature.tabularFigures()],
@@ -74,6 +75,7 @@ class WhiskeyMark extends StatelessWidget {
                 Text(
                   'Pitch: ${_formatAngle(pitch)}',
                   style: TextStyle(
+                    fontFamily: hudFont,
                     fontSize: fontSize * 0.5,
                     fontWeight: FontWeight.w400,
                     fontFeatures: const [FontFeature.tabularFigures()],
@@ -87,6 +89,7 @@ class WhiskeyMark extends StatelessWidget {
             Text(
               'Attitude',
               style: TextStyle(
+                fontFamily: hudFont,
                 fontSize: fontSize * 0.8,
                 fontWeight: FontWeight.w400,
                 color: theme.subdued,

pubspec.yaml

@@ -57,6 +57,12 @@ flutter:
   # the material Icons class.
   uses-material-design: true
 
+  # "Alte DIN 1451 Mittelschrift" (Peter Wiegel), the HUD face of smart-serow and gps-speedo.
+  fonts:
+    - family: DIN1451
+      fonts:
+        - asset: assets/fonts/din1451alt.ttf
+
   # Exact copies of contracts files (tool/sync-contracts.sh); crosscheck verifies them.
   assets:
     - assets/contracts/checklists/