Complete working floating window implementation

Major improvements to floating window overlay:

Architecture:
- Clean client-server model: main app as GPS backend, overlay as display client
- Single GPS stream eliminates resource conflicts and sync issues
- Real-time data push: speed, heading, theme, and unit changes sync instantly

Functionality:
- Proper system screen resolution detection and size synchronization
- Main app calculates overlay size, shares exact dimensions with overlay
- Navigation area tap toggles overlay (show/close), long-press always closes
- Comprehensive debug metrics for troubleshooting

Technical fixes:
- Eliminated duplicate GPS streams for better battery life
- Fixed size calculation mismatches between main app and overlay
- Proper overlay state tracking with _isOverlayActive boolean
- Reverted to withOpacity() per NOTES.txt (simpler than Color.fromARGB)

Debug metrics include:
- Creation/destruction signals with 🟢/🔴 indicators
- Real-time data updates with 📡/📤 send/receive tracking
- Window sizing info with 📐 dimensions and font calculations
- User interaction feedback with 🖱️ tap/long-press detection

This implementation provides reliable floating window functionality
with proper data synchronization and efficient resource usage.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

lib/main.dart

@@ -15,6 +15,7 @@ void main() {
 // Entry point for overlay window
 @pragma("vm:entry-point")
 void overlayMain() {
+  print('[Overlay] 🚀 overlayMain() called');
   runApp(const MaterialApp(
     debugShowCheckedModeBanner: false,
     home: OverlaySpeedometer(),
@@ -58,6 +59,7 @@ class _SpeedometerScreenState extends State<SpeedometerScreen> with WidgetsBindi
   StreamSubscription<Position>? _positionSubscription;
   String _errorMessage = '';
   bool _isInBackground = false;
+  bool _isOverlayActive = false;
 
   @override
   void initState() {
@@ -149,49 +151,93 @@ class _SpeedometerScreenState extends State<SpeedometerScreen> with WidgetsBindi
       _heading = position.heading;
       _errorMessage = '';
     });
+    
+    // Push display data to overlay if active
+    _pushDataToOverlay();
+  }
+  
+  void _pushDataToOverlay() {
+    // Send complete display data to overlay including screen size
+    final displaySpeed = _currentUnit.convert(_speed);
+    final speedText = displaySpeed < 1.0 ? '--' : displaySpeed.toInt().toString();
+    final headingText = GpsService.formatHeading(_heading);
+    
+    // Get system screen size to share with overlay
+    final window = WidgetsBinding.instance.platformDispatcher.views.first;
+    final systemSize = window.physicalSize / window.devicePixelRatio;
+    
+    print('[Main] 📤 SENDING to overlay:');
+    print('  speedText: "$speedText"');
+    print('  headingText: "$headingText"');
+    print('  direction: ${_heading.toStringAsFixed(1)}°');
+    print('  unit: ${_currentUnit.label}, theme: $_currentThemeIndex');
+    print('  systemScreen: ${systemSize.width.round()}x${systemSize.height.round()}');
+    
+    // Calculate overlay size the same way as when launching
+    final overlayWidth = (systemSize.width * 0.4).round();
+    final overlayHeight = (overlayWidth * 0.5).round();
+    
+    FlutterOverlayWindow.shareData({
+      'action': 'updateDisplay',
+      'speedText': speedText,
+      'headingText': headingText,
+      'heading': _heading,
+      'unitIndex': _currentUnit.index,
+      'themeIndex': _currentThemeIndex,
+      'systemScreenWidth': systemSize.width,
+      'systemScreenHeight': systemSize.height,
+      'overlayWidth': overlayWidth.clamp(280, 480).toDouble(),
+      'overlayHeight': overlayHeight.clamp(140, 240).toDouble(),
+    });
   }
 
   void _cycleUnit() {
     setState(() {
       _currentUnit = _currentUnit.next;
     });
-    // Share unit change with overlay if active
-    FlutterOverlayWindow.shareData({
-      'action': 'updateSettings',
-      'unitIndex': _currentUnit.index,
-      'themeIndex': _currentThemeIndex,
-    });
+    // Push updated display data to overlay
+    _pushDataToOverlay();
   }
 
   void _cycleTheme() {
     setState(() {
       _currentThemeIndex = ColorThemes.getNextThemeIndex(_currentThemeIndex);
     });
-    // Share theme change with overlay if active
-    FlutterOverlayWindow.shareData({
-      'action': 'updateSettings',
-      'themeIndex': _currentThemeIndex,
-      'unitIndex': _currentUnit.index,
-    });
+    // Push updated display data to overlay
+    _pushDataToOverlay();
   }
 
   Future<void> _showFloatingWindow() async {
     try {
-      // Get screen dimensions for proportional sizing
-      final screenSize = MediaQuery.of(context).size;
-      final overlayWidth = (screenSize.width * 0.4).round(); // 40% of screen width
+      // Get actual system screen resolution for proportional sizing
+      final window = WidgetsBinding.instance.platformDispatcher.views.first;
+      final systemSize = window.physicalSize / window.devicePixelRatio;
+      final overlayWidth = (systemSize.width * 0.4).round(); // 40% of system screen width
       final overlayHeight = (overlayWidth * 0.5).round(); // 2:1 aspect ratio
       
-      // Share current unit and theme with overlay
+      // Debug info for development
+      // print('[Main] System resolution: ${systemSize.width.round()}x${systemSize.height.round()}');
+      // print('[Main] Calculated overlay size: ${overlayWidth}x${overlayHeight}');
+      
+      // Send initial display data to overlay including screen size
+      final displaySpeed = _currentUnit.convert(_speed);
+      final speedText = displaySpeed < 1.0 ? '--' : displaySpeed.toInt().toString();
+      final headingText = GpsService.formatHeading(_heading);
+      
       await FlutterOverlayWindow.shareData({
-        'action': 'updateSettings',
+        'action': 'updateDisplay',
+        'speedText': speedText,
+        'headingText': headingText,
+        'heading': _heading,
         'unitIndex': _currentUnit.index,
         'themeIndex': _currentThemeIndex,
-        'screenWidth': screenSize.width,
-        'screenHeight': screenSize.height,
+        'systemScreenWidth': systemSize.width,
+        'systemScreenHeight': systemSize.height,
+        'overlayWidth': overlayWidth.clamp(280, 480).toDouble(),
+        'overlayHeight': overlayHeight.clamp(140, 240).toDouble(),
       });
 
-      // Show the overlay with hybrid sizing - proportional but with reasonable limits
+      // Show the overlay with proportional sizing based on system resolution
       await FlutterOverlayWindow.showOverlay(
         enableDrag: true,
         overlayTitle: "GPS Speedometer",
@@ -199,20 +245,34 @@ class _SpeedometerScreenState extends State<SpeedometerScreen> with WidgetsBindi
         flag: OverlayFlag.defaultFlag,
         visibility: NotificationVisibility.visibilityPublic,
         positionGravity: PositionGravity.none,
-        // Use proportional sizing with minimum reasonable dimensions
-        width: overlayWidth.clamp(280, 400),
-        height: overlayHeight.clamp(140, 300),
+        // Use system-based proportional sizing with reasonable limits
+        width: overlayWidth.clamp(280, 480),
+        height: overlayHeight.clamp(140, 240),
       );
+      
+      print('[Main] 🟢 OVERLAY LAUNCHED - Size: ${overlayWidth.clamp(280, 480)}x${overlayHeight.clamp(140, 240)}');
+      setState(() {
+        _isOverlayActive = true;
+      });
     } catch (e) {
       // Silent error handling - floating window issues shouldn't crash main app
     }
   }
 
   Future<void> _closeFloatingWindow() async {
+    if (!_isOverlayActive) {
+      print('[Main] ⚠️  No overlay to close');
+      return;
+    }
+    
     try {
       await FlutterOverlayWindow.closeOverlay();
+      print('[Main] 🔴 OVERLAY CLOSED - Requested from main app');
+      setState(() {
+        _isOverlayActive = false;
+      });
     } catch (e) {
-      // Silent error handling - floating window issues shouldn't crash main app
+      print('[Main] ❌ Error closing overlay: $e');
     }
   }
   
@@ -354,8 +414,18 @@ class _SpeedometerScreenState extends State<SpeedometerScreen> with WidgetsBindi
         Expanded(
           flex: 32,
           child: GestureDetector(
-            onTap: _showFloatingWindow, // Tap navigation icon to show floating window
-            onLongPress: _closeFloatingWindow, // Long press to close floating window
+            onTap: () {
+              print('[Main] 🖱️  Navigation area tapped - overlay active: $_isOverlayActive');
+              if (_isOverlayActive) {
+                _closeFloatingWindow();
+              } else {
+                _showFloatingWindow();
+              }
+            },
+            onLongPress: () {
+              print('[Main] 🖱️  Navigation area long-pressed - overlay active: $_isOverlayActive');
+              _closeFloatingWindow();
+            },
             child: Container(
               width: double.infinity,
               color: Colors.transparent,
@@ -427,7 +497,11 @@ class _SpeedometerScreenState extends State<SpeedometerScreen> with WidgetsBindi
                   )
                 else ...[
                   Flexible(
-                    flex: 4,
+                    flex: 1,
+                    child: FittedBox(),
+                  ),
+                  Flexible(
+                    flex: 20,
                     child: GestureDetector(
                       onTap: _cycleTheme,
                       child: FittedBox(
@@ -437,7 +511,7 @@ class _SpeedometerScreenState extends State<SpeedometerScreen> with WidgetsBindi
                     ),
                   ),
                   Flexible(
-                    flex: 1,
+                    flex: 7,
                     child: GestureDetector(
                       onTap: _cycleUnit,
                       child: FittedBox(
@@ -453,6 +527,10 @@ class _SpeedometerScreenState extends State<SpeedometerScreen> with WidgetsBindi
                       ),
                     ),
                   ),
+                  Flexible(
+                    flex: 5,
+                    child: FittedBox(),
+                  ),
                 ],
               ],
             ),
@@ -462,8 +540,18 @@ class _SpeedometerScreenState extends State<SpeedometerScreen> with WidgetsBindi
         Expanded(
           flex: 33,
           child: GestureDetector(
-            onTap: _showFloatingWindow,
-            onLongPress: _closeFloatingWindow, // Long press to close floating window
+            onTap: () {
+              print('[Main] 🖱️  Navigation area tapped (landscape) - overlay active: $_isOverlayActive');
+              if (_isOverlayActive) {
+                _closeFloatingWindow();
+              } else {
+                _showFloatingWindow();
+              }
+            },
+            onLongPress: () {
+              print('[Main] 🖱️  Navigation area long-pressed (landscape) - overlay active: $_isOverlayActive');
+              _closeFloatingWindow();
+            },
             child: Container(
               height: double.infinity,
               color: Colors.transparent,
@@ -517,83 +605,95 @@ class OverlaySpeedometer extends StatefulWidget {
 }
 
 class _OverlaySpeedometerState extends State<OverlaySpeedometer> {
-  double _speed = 0.0;
+  String _speedText = '--';
+  String _headingText = 'N/A';
   double _heading = -1.0;
-  SpeedUnit _currentUnit = SpeedUnit.kmh;
   int _currentThemeIndex = 0;
-  StreamSubscription<Position>? _positionSubscription;
-  double _screenWidth = 400;
+  double _systemScreenWidth = 400;
+  double _overlayWidth = 280;
+  double _overlayHeight = 140;
 
   @override
   void initState() {
     super.initState();
+    print('[Overlay] 🟢 CREATED - Floating window initialized');
+    _getSystemScreenSize();
     _listenToMainAppMessages();
-    _initializeGps();
+  }
+
+  void _getSystemScreenSize() {
+    try {
+      // Get actual system screen resolution, not just app window size
+      final window = WidgetsBinding.instance.platformDispatcher.views.first;
+      final physicalSize = window.physicalSize;
+      final devicePixelRatio = window.devicePixelRatio;
+      final systemSize = physicalSize / devicePixelRatio;
+      
+      print('[Overlay] 🔍 Screen detection:');
+      print('  physicalSize: ${physicalSize.width.round()}x${physicalSize.height.round()}');
+      print('  devicePixelRatio: $devicePixelRatio');
+      print('  calculated systemSize: ${systemSize.width.round()}x${systemSize.height.round()}');
+      
+      setState(() {
+        _systemScreenWidth = systemSize.width;
+      });
+      
+      print('[Overlay] ✅ _systemScreenWidth set to: ${_systemScreenWidth.round()}');
+    } catch (e) {
+      print('[Overlay] ❌ Error getting system screen size: $e');
+      // Fallback to reasonable default
+      setState(() {
+        _systemScreenWidth = 400;
+      });
+    }
   }
 
   void _listenToMainAppMessages() {
     FlutterOverlayWindow.overlayListener.listen((data) {
-      if (data is Map) {
-        if (data.containsKey('unitIndex')) {
-          setState(() {
-            _currentUnit = SpeedUnit.values[data['unitIndex'] ?? 0];
-          });
-        }
-        if (data.containsKey('themeIndex')) {
-          setState(() {
-            _currentThemeIndex = data['themeIndex'] ?? 0;
-          });
-        }
-        if (data.containsKey('screenWidth')) {
-          setState(() {
-            _screenWidth = data['screenWidth']?.toDouble() ?? 400;
-          });
-        }
+      if (data is Map && data['action'] == 'updateDisplay') {
+        setState(() {
+          _speedText = data['speedText'] ?? '--';
+          _headingText = data['headingText'] ?? 'N/A';
+          _heading = data['heading']?.toDouble() ?? -1.0;
+          _currentThemeIndex = data['themeIndex'] ?? 0;
+          // Update screen size and overlay dimensions if provided by main app
+          if (data.containsKey('systemScreenWidth')) {
+            _systemScreenWidth = data['systemScreenWidth']?.toDouble() ?? _systemScreenWidth;
+          }
+          if (data.containsKey('overlayWidth')) {
+            _overlayWidth = data['overlayWidth']?.toDouble() ?? _overlayWidth;
+          }
+          if (data.containsKey('overlayHeight')) {
+            _overlayHeight = data['overlayHeight']?.toDouble() ?? _overlayHeight;
+          }
+        });
+        
+        print('[Overlay] 📡 UPDATE received:');
+        print('  speedText: "$_speedText"');
+        print('  headingText: "$_headingText"'); 
+        print('  direction: ${_heading.toStringAsFixed(1)}°');
+        print('  themeIndex: $_currentThemeIndex');
+        print('  systemScreenWidth: ${_systemScreenWidth.round()}');
+        print('  overlaySize from main: ${_overlayWidth.round()}x${_overlayHeight.round()}');
       }
     });
   }
 
-  Future<void> _initializeGps() async {
-    try {
-      final serviceEnabled = await GpsService.isLocationServiceEnabled();
-      if (!serviceEnabled) return;
-
-      final permissionGranted = await GpsService.requestPermissions();
-      if (!permissionGranted) return;
-
-      _positionSubscription = GpsService.positionStream.listen(
-        (position) {
-          setState(() {
-            _speed = position.speed;
-            _heading = position.heading;
-          });
-        },
-        onError: (error) {
-          // Silent error handling for overlay
-        },
-      );
-    } catch (e) {
-      // Silent error handling for overlay
-    }
-  }
-
   @override
   void dispose() {
-    _positionSubscription?.cancel();
+    print('[Overlay] 🔴 DESTROYED - Floating window disposed');
+    // No GPS subscription to cancel - overlay is display-only
     super.dispose();
   }
 
   @override
   Widget build(BuildContext context) {
     final currentTheme = ColorThemes.getTheme(_currentThemeIndex);
-    final displaySpeed = _currentUnit.convert(_speed);
-    // Per NOTES.txt: Speed section shows only integral part (no decimal, no unit)
-    final speedText = displaySpeed < 1.0 ? '--' : displaySpeed.toInt().toString();
     
-    // Calculate proportional dimensions
-    final overlayWidth = (_screenWidth * 0.4);
-    final overlayHeight = (overlayWidth * 0.5);
-    final fontSize = (overlayWidth * 0.2); // Font size proportional to width
+    // Use overlay dimensions provided by main app (not calculated locally)
+    final fontSize = (_overlayWidth * 0.2); // Font size proportional to actual overlay width
+    
+    print('[Overlay] 📐 Window size: ${_overlayWidth.round()}x${_overlayHeight.round()}, fontSize: ${fontSize.round()}');
 
     return Material(
       color: Colors.transparent,
@@ -603,21 +703,10 @@ class _OverlaySpeedometerState extends State<OverlaySpeedometer> {
         height: double.infinity,
         child: Container(
           decoration: BoxDecoration(
-            // Use proper color opacity without deprecated properties
-            color: Color.fromARGB(
-              ((currentTheme.background.a * 255.0).round() * 0.85).round(),
-              (currentTheme.background.r * 255.0).round(),
-              (currentTheme.background.g * 255.0).round(),
-              (currentTheme.background.b * 255.0).round(),
-            ),
+            color: currentTheme.background.withOpacity(0.85),
             borderRadius: BorderRadius.circular(12),
             border: Border.all(
-              color: Color.fromARGB(
-                ((currentTheme.speedText.a * 255.0).round() * 0.3).round(),
-                (currentTheme.speedText.r * 255.0).round(),
-                (currentTheme.speedText.g * 255.0).round(),
-                (currentTheme.speedText.b * 255.0).round(),
-              ), 
+              color: currentTheme.speedText.withOpacity(0.3), 
               width: 1
             ),
           ),
@@ -635,7 +724,7 @@ class _OverlaySpeedometerState extends State<OverlaySpeedometer> {
                         child: FittedBox(
                           fit: BoxFit.contain,
                           child: Text(
-                            speedText,
+                            _speedText,
                             style: TextStyle(
                               fontSize: fontSize,
                               fontWeight: FontWeight.w300,
@@ -674,7 +763,7 @@ class _OverlaySpeedometerState extends State<OverlaySpeedometer> {
                             child: FittedBox(
                               fit: BoxFit.contain,
                               child: Text(
-                                GpsService.formatHeading(_heading),
+                                _headingText,
                                 style: TextStyle(
                                   fontSize: fontSize * 0.4,
                                   color: currentTheme.headingText,
@@ -696,21 +785,20 @@ class _OverlaySpeedometerState extends State<OverlaySpeedometer> {
                 child: GestureDetector(
                   onTap: () => FlutterOverlayWindow.closeOverlay(),
                   child: Container(
-                    width: overlayHeight * 0.2,
-                    height: overlayHeight * 0.2,
+                    width: _overlayHeight * 0.2,
+                    height: _overlayHeight * 0.2,
                     decoration: BoxDecoration(
-                      // Avoid deprecated withOpacity - use Color.fromARGB instead
-                      color: const Color.fromARGB(153, 244, 67, 54), // red with 60% opacity
-                      borderRadius: BorderRadius.circular(overlayHeight * 0.1),
+                      color: Colors.red.withOpacity(0.6),
+                      borderRadius: BorderRadius.circular(_overlayHeight * 0.1),
                       border: Border.all(
-                        color: const Color.fromARGB(204, 255, 255, 255), // white with 80% opacity
+                        color: Colors.white.withOpacity(0.8),
                         width: 1
                       ),
                     ),
                     child: Icon(
                       Icons.close,
-                      color: const Color.fromARGB(229, 255, 255, 255), // white with 90% opacity
-                      size: overlayHeight * 0.15,
+                      color: Colors.white.withOpacity(0.9),
+                      size: _overlayHeight * 0.15,
                     ),
                   ),
                 ),