settings: unit system

lib/l10n/app_en.arb

@@ -173,6 +173,11 @@
   "coordinateFormatDecimal": "Decimal degrees",
   "@coordinateFormatDecimal": {},
 
+  "unitSystemMetric": "Metric",
+  "@unitSystemMetric": {},
+  "unitSystemImperial": "Imperial",
+  "@unitSystemImperial": {},
+
   "videoLoopModeNever": "Never",
   "@videoLoopModeNever": {},
   "videoLoopModeShortOnly": "Short videos only",
@@ -835,6 +840,10 @@
   "@settingsCoordinateFormatTile": {},
   "settingsCoordinateFormatTitle": "Coordinate Format",
   "@settingsCoordinateFormatTitle": {},
+  "settingsUnitSystemTile": "Units",
+  "@settingsUnitSystemTile": {},
+  "settingsUnitSystemTitle": "Units",
+  "@settingsUnitSystemTitle": {},
 
   "statsPageTitle": "Stats",
   "@statsPageTitle": {},

lib/l10n/app_ko.arb

@@ -86,6 +86,9 @@
   "coordinateFormatDms": "도분초",
   "coordinateFormatDecimal": "소수점",
 
+  "unitSystemMetric": "미터법",
+  "unitSystemImperial": "야드파운드법",
+
   "videoLoopModeNever": "반복 안 함",
   "videoLoopModeShortOnly": "짧은 동영상만 반복",
   "videoLoopModeAlways": "항상 반복",
@@ -409,6 +412,8 @@
   "settingsLanguage": "언어",
   "settingsCoordinateFormatTile": "좌표 표현",
   "settingsCoordinateFormatTitle": "좌표 표현",
+  "settingsUnitSystemTile": "단위법",
+  "settingsUnitSystemTitle": "단위법",
 
   "statsPageTitle": "통계",
   "statsImage": "{count, plural, other{사진}}",

lib/model/settings/defaults.dart

@@ -82,6 +82,7 @@ class SettingsDefaults {
   static const infoMapStyle = EntryMapStyle.stamenWatercolor; // `infoMapStyle` has a contextual default value
   static const infoMapZoom = 12.0;
   static const coordinateFormat = CoordinateFormat.dms;
+  static const unitSystem = UnitSystem.metric;
 
   // rendering
   static const imageBackground = EntryBackground.white;

lib/model/settings/enums.dart

@@ -13,4 +13,6 @@ enum EntryMapStyle { googleNormal, googleHybrid, googleTerrain, osmHot, stamenTo
 
 enum KeepScreenOn { never, viewerOnly, always }
 
+enum UnitSystem { metric, imperial }
+
 enum VideoLoopMode { never, shortOnly, always }

lib/model/settings/settings.dart

@@ -98,6 +98,7 @@ class Settings extends ChangeNotifier {
   static const infoMapStyleKey = 'info_map_style';
   static const infoMapZoomKey = 'info_map_zoom';
   static const coordinateFormatKey = 'coordinates_format';
+  static const unitSystemKey = 'unit_system';
 
   // rendering
   static const imageBackgroundKey = 'image_background';
@@ -379,6 +380,10 @@ class Settings extends ChangeNotifier {
 
   set coordinateFormat(CoordinateFormat newValue) => setAndNotify(coordinateFormatKey, newValue.toString());
 
+  UnitSystem get unitSystem => getEnumOrDefault(unitSystemKey, SettingsDefaults.unitSystem, UnitSystem.values);
+
+  set unitSystem(UnitSystem newValue) => setAndNotify(unitSystemKey, newValue.toString());
+
   // rendering
 
   EntryBackground get imageBackground => getEnumOrDefault(imageBackgroundKey, SettingsDefaults.imageBackground, EntryBackground.values);
@@ -574,6 +579,7 @@ class Settings extends ChangeNotifier {
             case subtitleTextAlignmentKey:
             case infoMapStyleKey:
             case coordinateFormatKey:
+            case unitSystemKey:
             case imageBackgroundKey:
             case accessibilityAnimationsKey:
             case timeToTakeActionKey:

lib/model/settings/unit_system.dart

@@ -0,0 +1,15 @@
+import 'package:aves/widgets/common/extensions/build_context.dart';
+import 'package:flutter/widgets.dart';
+
+import 'enums.dart';
+
+extension ExtraUnitSystem on UnitSystem {
+  String getName(BuildContext context) {
+    switch (this) {
+      case UnitSystem.metric:
+        return context.l10n.unitSystemMetric;
+      case UnitSystem.imperial:
+        return context.l10n.unitSystemImperial;
+    }
+  }
+}

lib/widgets/common/map/leaflet/map.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 
 import 'package:aves/model/entry.dart';
 import 'package:aves/model/settings/enums.dart';
+import 'package:aves/model/settings/settings.dart';
 import 'package:aves/theme/durations.dart';
 import 'package:aves/utils/debouncer.dart';
 import 'package:aves/widgets/common/map/buttons.dart';
@@ -163,7 +164,9 @@ class _EntryLeafletMapState extends State<EntryLeafletMap> with TickerProviderSt
       mapController: _leafletMapController,
       nonRotatedChildren: [
         ScaleLayerWidget(
-          options: ScaleLayerOptions(),
+          options: ScaleLayerOptions(
+            unitSystem: settings.unitSystem,
+          ),
         ),
       ],
       children: [

lib/widgets/common/map/leaflet/scale_layer.dart

@@ -1,5 +1,4 @@
-import 'dart:math';
-
+import 'package:aves/model/settings/enums.dart';
 import 'package:aves/widgets/common/basic/outlined_text.dart';
 import 'package:aves/widgets/common/map/leaflet/scalebar_utils.dart';
 import 'package:flutter/material.dart';
@@ -7,10 +6,12 @@ import 'package:flutter_map/flutter_map.dart';
 import 'package:flutter_map/plugin_api.dart';
 
 class ScaleLayerOptions extends LayerOptions {
+  final UnitSystem unitSystem;
   final Widget Function(double width, String distance) builder;
 
   ScaleLayerOptions({
     Key? key,
+    this.unitSystem = UnitSystem.metric,
     this.builder = defaultBuilder,
     rebuild,
   }) : super(key: key, rebuild: rebuild);
@@ -41,7 +42,7 @@ class ScaleLayer extends StatelessWidget {
 
   // ignore: prefer_void_to_null
   final Stream<Null> stream;
-  final scale = [
+  static const List<double> scaleMeters = [
     25000000,
     15000000,
     8000000,
@@ -67,6 +68,10 @@ class ScaleLayer extends StatelessWidget {
     5,
   ];
 
+  static const double metersInAKilometer = 1000;
+  static const double metersInAMile = 1609.344;
+  static const double metersInAFoot = 0.3048;
+
   ScaleLayer(this.scaleLayerOpts, this.map, this.stream) : super(key: scaleLayerOpts.key);
 
   @override
@@ -83,11 +88,33 @@ class ScaleLayer extends StatelessWidget {
                 : latitude > 60
                     ? 3
                     : 2);
-        final distance = scale[max(0, min(20, level))].toDouble();
+        final scaleLevel = level.clamp(0, 20);
+        late final double distanceMeters;
+        late final String displayDistance;
+        switch (scaleLayerOpts.unitSystem) {
+          case UnitSystem.metric:
+            // meters
+            distanceMeters = scaleMeters[scaleLevel];
+            displayDistance = distanceMeters >= metersInAKilometer ? '${(distanceMeters / metersInAKilometer).toStringAsFixed(0)} km' : '${distanceMeters.toStringAsFixed(0)} m';
+            break;
+          case UnitSystem.imperial:
+            if (scaleLevel < 15) {
+              // miles
+              final distanceMiles = scaleMeters[scaleLevel + 1] / 1000;
+              distanceMeters = distanceMiles * metersInAMile;
+              displayDistance = '${distanceMiles.toStringAsFixed(0)} mi';
+            } else {
+              // feet
+              final distanceFeet = scaleMeters[scaleLevel - 1];
+              distanceMeters = distanceFeet * metersInAFoot;
+              displayDistance = '${distanceFeet.toStringAsFixed(0)} ft';
+            }
+            break;
+        }
+
         final start = map.project(center);
-        final targetPoint = ScaleBarUtils.calculateEndingGlobalCoordinates(center, 90, distance);
+        final targetPoint = ScaleBarUtils.calculateEndingGlobalCoordinates(center, 90, distanceMeters);
         final end = map.project(targetPoint);
-        final displayDistance = distance > 999 ? '${(distance / 1000).toStringAsFixed(0)} km' : '${distance.toStringAsFixed(0)} m';
         final width = end.x - (start.x as double);
 
         return scaleLayerOpts.builder(width, displayDistance);

lib/widgets/common/map/leaflet/scalebar_utils.dart

@@ -3,7 +3,7 @@ import 'dart:math';
 import 'package:latlong2/latlong.dart';
 
 class ScaleBarUtils {
-  static LatLng calculateEndingGlobalCoordinates(LatLng start, double startBearing, double distance) {
+  static LatLng calculateEndingGlobalCoordinates(LatLng start, double startBearing, double distanceMeters) {
     var mSemiMajorAxis = 6378137.0; //WGS84 major axis
     var mSemiMinorAxis = (1.0 - 1.0 / 298.257223563) * 6378137.0;
     var mFlattening = 1.0 / 298.257223563;
@@ -18,7 +18,7 @@ class ScaleBarUtils {
     var alpha1 = degToRadian(startBearing);
     var cosAlpha1 = cos(alpha1);
     var sinAlpha1 = sin(alpha1);
-    var s = distance;
+    var s = distanceMeters;
     var tanU1 = (1.0 - f) * tan(phi1);
     var cosU1 = 1.0 / sqrt(1.0 + tanU1 * tanU1);
     var sinU1 = tanU1 * cosU1;

lib/widgets/settings/language/language.dart

@@ -1,6 +1,7 @@
 import 'package:aves/model/settings/coordinate_format.dart';
 import 'package:aves/model/settings/enums.dart';
 import 'package:aves/model/settings/settings.dart';
+import 'package:aves/model/settings/unit_system.dart';
 import 'package:aves/theme/icons.dart';
 import 'package:aves/utils/color_utils.dart';
 import 'package:aves/utils/constants.dart';
@@ -23,6 +24,7 @@ class LanguageSection extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final currentCoordinateFormat = context.select<Settings, CoordinateFormat>((s) => s.coordinateFormat);
+    final currentUnitSystem = context.select<Settings, UnitSystem>((s) => s.unitSystem);
 
     return AvesExpansionTile(
       // use a fixed value instead of the title to identify this expansion tile
@@ -55,6 +57,23 @@ class LanguageSection extends StatelessWidget {
             }
           },
         ),
+        ListTile(
+          title: Text(context.l10n.settingsUnitSystemTile),
+          subtitle: Text(currentUnitSystem.getName(context)),
+          onTap: () async {
+            final value = await showDialog<UnitSystem>(
+              context: context,
+              builder: (context) => AvesSelectionDialog<UnitSystem>(
+                initialValue: currentUnitSystem,
+                options: Map.fromEntries(UnitSystem.values.map((v) => MapEntry(v, v.getName(context)))),
+                title: context.l10n.settingsUnitSystemTitle,
+              ),
+            );
+            if (value != null) {
+              settings.unitSystem = value;
+            }
+          },
+        ),
       ],
     );
   }