fix(train): the maps stop at zoom 18, beyond which they drew nothing

vector_map_tiles draws its tiles as pictures and stops at zoom 18, while
the maps let people zoom further, onto a grey map.

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

apps/train/halkyon_train_flutter/lib/src/feature/map/widget/map_tiles.dart

@@ -8,6 +8,10 @@ import 'package:vector_map_tiles/vector_map_tiles.dart';
 import 'package:vector_tile_renderer/vector_tile_renderer.dart'
     show SpriteIndexReader, ThemeReader;
 
+/// The closest every map zooms: the tile layer, drawing the tiles as
+/// pictures (vector_map_tiles' raster mode), draws nothing beyond zoom 18.
+const mapMaxZoom = 18.0;
+
 /// Builds the map's tile layer for a source: [vectorTiles] in the app, none
 /// in widget tests, which reach no network.
 typedef MapTiles = Widget Function(MapSource source);

apps/train/halkyon_train_flutter/lib/src/feature/recording/widget/recording_screen.dart

@@ -6,6 +6,7 @@ import 'package:halkyon_app/halkyon_app.dart';
 import 'package:halkyon_train_client/halkyon_train_client.dart' show MapSource;
 import 'package:halkyon_train_flutter/l10n/app_localizations.dart';
 import 'package:halkyon_train_flutter/src/app/train_dependencies.dart';
+import 'package:halkyon_train_flutter/src/feature/map/widget/map_tiles.dart';
 import 'package:halkyon_train_flutter/src/feature/plan/model/plan.dart';
 import 'package:halkyon_train_flutter/src/feature/plan/widget/plan_texts.dart';
 import 'package:halkyon_train_flutter/src/feature/recording/bloc/recording_bloc.dart';
@@ -529,6 +530,7 @@ class _RecordingMapState() extends State<_RecordingMap> {
           FlutterMap(
             mapController: _map,
             options: MapOptions(
+              maxZoom: mapMaxZoom,
               initialCenter: _here ?? const LatLng(50, 10),
               initialZoom: _here == null ? 4 : 16,
               interactionOptions: const InteractionOptions(

apps/train/halkyon_train_flutter/lib/src/feature/route/widget/route_screen.dart

@@ -5,6 +5,7 @@ import 'package:halkyon_train_client/halkyon_train_client.dart' show MapSource;
 import 'package:halkyon_train_flutter/l10n/app_localizations.dart';
 import 'package:halkyon_train_flutter/src/app/train_dependencies.dart';
 import 'package:halkyon_train_flutter/src/feature/map/data/offline_maps.dart';
+import 'package:halkyon_train_flutter/src/feature/map/widget/map_tiles.dart';
 import 'package:halkyon_train_flutter/src/feature/recording/data/recorder_platform.dart';
 import 'package:halkyon_train_flutter/src/feature/recording/widget/recording_texts.dart';
 import 'package:halkyon_train_flutter/src/feature/route/bloc/place_search_cubit.dart';
@@ -255,6 +256,7 @@ class _RouteMapState() extends State<_RouteMap> {
             FlutterMap(
               mapController: _map,
               options: MapOptions(
+                maxZoom: mapMaxZoom,
                 initialCameraFit: _fit.length > 1
                     ? CameraFit.coordinates(
                         coordinates: _fit,

apps/train/halkyon_train_flutter/lib/src/feature/workout/widget/workout_screen.dart

@@ -4,6 +4,7 @@ import 'package:halkyon_app/halkyon_app.dart';
 import 'package:halkyon_train_client/halkyon_train_client.dart' show MapSource;
 import 'package:halkyon_train_flutter/l10n/app_localizations.dart';
 import 'package:halkyon_train_flutter/src/app/train_dependencies.dart';
+import 'package:halkyon_train_flutter/src/feature/map/widget/map_tiles.dart';
 import 'package:halkyon_train_flutter/src/feature/plan/widget/plan_texts.dart';
 import 'package:halkyon_train_flutter/src/feature/recording/model/recording.dart';
 import 'package:halkyon_train_flutter/src/feature/recording/widget/recording_texts.dart';
@@ -386,6 +387,7 @@ class const _TrackMap({
     final (start, end) = (all.first, all.last);
     return FlutterMap(
       options: MapOptions(
+        maxZoom: mapMaxZoom,
         initialCameraFit: all.length > 1
             ? CameraFit.coordinates(
                 coordinates: all,

apps/train/halkyon_train_flutter/test/app/train_app_test.dart

@@ -21,6 +21,7 @@ import 'package:halkyon_train_flutter/src/feature/loop/data/polar_loop.dart';
 import 'package:halkyon_train_flutter/src/feature/loop/model/loop_figures.dart';
 import 'package:halkyon_train_flutter/src/feature/map/data/map_source_repository.dart';
 import 'package:halkyon_train_flutter/src/feature/map/data/offline_maps.dart';
+import 'package:halkyon_train_flutter/src/feature/map/widget/map_tiles.dart';
 import 'package:halkyon_train_flutter/src/feature/music/data/recorder_music.dart';
 import 'package:halkyon_train_flutter/src/feature/plan/data/plan_repository.dart';
 import 'package:halkyon_train_flutter/src/feature/plan/model/plan.dart';
@@ -2268,6 +2269,19 @@ void main() {
       expect(find.textContaining('No way found there'), findsNothing);
     });
 
+    testWidgets('the maps stop where their tiles stop being drawn', (
+      tester,
+    ) async {
+      await openRoutes(tester);
+      await tester.tap(find.text('New route'));
+      await tester.pumpAndSettle();
+
+      expect(
+        tester.widget<FlutterMap>(find.byType(FlutterMap)).options.maxZoom,
+        mapMaxZoom,
+      );
+    });
+
     testWidgets('an instance that plans no routes says so', (tester) async {
       routing.isOffered = false;
       await openRoutes(tester);
@@ -2648,6 +2662,10 @@ void main() {
       await tester.pumpAndSettle();
 
       expect(find.byType(FlutterMap), findsOneWidget);
+      expect(
+        tester.widget<FlutterMap>(find.byType(FlutterMap)).options.maxZoom,
+        mapMaxZoom,
+      );
       expect(find.text('2.50 km'), findsOneWidget);
       expect(find.text('20 m'), findsOneWidget);
       expect(find.text('whole time'), findsOneWidget);