Added light theme option suitable for e-ink devices (#256)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/src/main/java/com/rtbishop/look4sat/MainActivity.kt

@@ -27,6 +27,8 @@ import android.view.View
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
 import androidx.core.splashscreen.SplashScreen.Companion.installSplashScreen
 import androidx.lifecycle.lifecycleScope
 import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
@@ -48,8 +50,10 @@ class MainActivity : ComponentActivity() {
         enableEdgeToEdge()
         super.onCreate(savedInstanceState)
         observeNightFilterState()
+        val settingsRepo = (applicationContext as IContainerProvider).getMainContainer().settingsRepo
         setContent {
-            MainTheme(isDarkTheme = true) { NavRoot() }
+            val otherSettings by settingsRepo.otherSettings.collectAsState()
+            MainTheme(isDarkTheme = !otherSettings.stateOfLightTheme) { NavRoot() }
         }
     }
 

core/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/MainTheme.kt

@@ -61,8 +61,8 @@ fun MainTheme(isDarkTheme: Boolean = isSystemInDarkTheme(), content: @Composable
             SideEffect {
                 val window = (view.context as ComponentActivity).window
                 val insetsController = WindowCompat.getInsetsController(window, view)
-                insetsController.isAppearanceLightStatusBars = false
+                insetsController.isAppearanceLightStatusBars = !isDarkTheme
-                insetsController.isAppearanceLightNavigationBars = false
+                insetsController.isAppearanceLightNavigationBars = !isDarkTheme
                 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
                     window.isNavigationBarContrastEnforced = false
                 }

core/presentation/src/main/res/values/strings.xml

@@ -266,6 +266,7 @@
     <string name="prefs_other_switch_sweep">Radar sweep</string>
     <string name="prefs_other_switch_sensors">Use sensors</string>
     <string name="prefs_other_switch_night_mode">Night filter</string>
+    <string name="prefs_other_switch_light_theme">Light theme</string>
     <string name="prefs_other_compass_offset">Radar compass offset</string>
     <string name="prefs_other_compass_offset_elev">Radar compass offset (elev)</string>
 

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapScreen.kt

@@ -122,6 +122,39 @@ private val moonIconPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
         android.graphics.PorterDuffColorFilter("#E0E0E0".toColorInt(), android.graphics.PorterDuff.Mode.SRC_IN)
 }
 
+/** Accent used for the station marker; recolored per theme so it stays visible on a light map. */
+private var mapAccentColor = "#FFE082".toColorInt()
+
+/** The dark-map filter (grayscale + invert) is only applied when NOT in light theme; cached to avoid rebuilds. */
+private val darkTileFilter by lazy { createColorFilter() }
+
+/**
+ * Recolor the shared overlay paints for the current theme. The light OSM tiles are white, so the
+ * dark-theme amber/grey overlays would vanish; light theme swaps them for dark, high-contrast colors.
+ * Must run before the set*() overlay builders on each frame, as several icons cache the paint color.
+ */
+private fun applyMapColors(isLightUi: Boolean) {
+    if (isLightUi) {
+        mapAccentColor = "#715C0C".toColorInt() // dark amber (matches app lightScheme primary)
+        footprintPaint.color = mapAccentColor
+        textPaint.color = "#1E1B13".toColorInt()
+        textPaint.setShadowLayer(3f, 3f, 3f, Color.WHITE)
+        sunIconPaint.colorFilter =
+            android.graphics.PorterDuffColorFilter(mapAccentColor, android.graphics.PorterDuff.Mode.SRC_IN)
+        moonIconPaint.colorFilter =
+            android.graphics.PorterDuffColorFilter("#4C4639".toColorInt(), android.graphics.PorterDuff.Mode.SRC_IN)
+    } else {
+        mapAccentColor = "#FFE082".toColorInt()
+        footprintPaint.color = mapAccentColor
+        textPaint.color = mapAccentColor
+        textPaint.setShadowLayer(3f, 3f, 3f, Color.BLACK)
+        sunIconPaint.colorFilter =
+            android.graphics.PorterDuffColorFilter(mapAccentColor, android.graphics.PorterDuff.Mode.SRC_IN)
+        moonIconPaint.colorFilter =
+            android.graphics.PorterDuffColorFilter("#E0E0E0".toColorInt(), android.graphics.PorterDuff.Mode.SRC_IN)
+    }
+}
+
 @Composable
 fun MapDestination() {
     val context = LocalContext.current
@@ -177,6 +210,8 @@ private fun MapScreen(uiState: MapState, onAction: (MapAction) -> Unit, mapView:
         ElevatedCard(modifier = Modifier.weight(1f)) {
             Box(contentAlignment = Alignment.BottomCenter) {
                 AndroidView({ mapView }) { view ->
+                    applyMapColors(uiState.isLightUi)
+                    view.overlayManager.tilesOverlay.setColorFilter(if (uiState.isLightUi) null else darkTileFilter)
                     uiState.stationPosition?.let { setStationPosition(it, view) }
                     uiState.track?.let { setSatelliteTrack(it, view) }
                     uiState.footprint?.let { setFootprint(it, view) }
@@ -288,7 +323,9 @@ private fun setStationPosition(stationPos: GeoPos, mapView: MapView) {
             mapView.overlays[OVERLAY_STATION] = Marker(mapView).apply {
                 setInfoWindow(null)
                 setAnchor(Marker.ANCHOR_CENTER, Marker.ANCHOR_BOTTOM)
-                icon = ContextCompat.getDrawable(mapView.context, R.drawable.ic_position)
+                icon = ContextCompat.getDrawable(mapView.context, R.drawable.ic_position)?.apply {
+                    setTint(mapAccentColor)
+                }
                 position = GeoPoint(stationPos.latitude, stationPos.longitude)
             }
         }
@@ -585,7 +622,7 @@ private fun rememberMapViewWithLifecycle(): MapView {
             zoomController.setVisibility(CustomZoomButtonsController.Visibility.NEVER)
             overlayManager.tilesOverlay.loadingBackgroundColor = Color.TRANSPARENT
             overlayManager.tilesOverlay.loadingLineColor = Color.TRANSPARENT
-            overlayManager.tilesOverlay.setColorFilter(createColorFilter())
+            // Tile color filter (dark inversion vs light) is applied per-theme in the AndroidView update block.
             setScrollableAreaLimitLatitude(maxLat, minLat, 0)
             overlays.addAll(Array(OVERLAY_COUNT) { FolderOverlay() })
         }

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapViewModel.kt

@@ -80,7 +80,7 @@ class MapViewModel(
     init {
         viewModelScope.launch {
             settingsRepo.otherSettings.collectLatest { settings ->
-                _uiState.update { it.copy(isUtc = settings.stateOfUtc) }
+                _uiState.update { it.copy(isUtc = settings.stateOfUtc, isLightUi = settings.stateOfLightTheme) }
             }
         }
         val (selectedCatNum, _) = satelliteRepo.selectedPass.value

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsScreen.kt

@@ -495,12 +495,24 @@ private fun OtherCard(settings: OtherSettings, onAction: (SettingsAction) -> Uni
                 color = MaterialTheme.colorScheme.primary
             )
             Spacer(modifier = Modifier.height(4.dp))
+            // Appearance: light theme (paired with a spacer to align with the two-column rows)
+            Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                SwitchTile(R.string.prefs_other_switch_light_theme, settings.stateOfLightTheme) {
+                    onAction(SettingsAction.ToggleLightTheme(it))
+                }
+                Spacer(modifier = Modifier.weight(1f))
+            }
+            Spacer(modifier = Modifier.height(4.dp))
             // Display preferences: UTC clock + night filter
             Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
                 SwitchTile(R.string.prefs_other_switch_utc, settings.stateOfUtc) {
                     onAction(SettingsAction.ToggleUtc(it))
                 }
-                SwitchTile(R.string.prefs_other_switch_night_mode, settings.stateOfNightMode) {
+                SwitchTile(
+                    R.string.prefs_other_switch_night_mode,
+                    settings.stateOfNightMode,
+                    enabled = !settings.stateOfLightTheme
+                ) {
                     onAction(SettingsAction.ToggleNightMode(it))
                 }
             }
@@ -573,7 +585,12 @@ private fun SwitchRow(labelResId: Int, checked: Boolean, onCheckedChange: (Boole
 }
 
 @Composable
-private fun RowScope.SwitchTile(labelResId: Int, checked: Boolean, onCheckedChange: (Boolean) -> Unit) {
+private fun RowScope.SwitchTile(
+    labelResId: Int,
+    checked: Boolean,
+    enabled: Boolean = true,
+    onCheckedChange: (Boolean) -> Unit
+) {
     Row(
         horizontalArrangement = Arrangement.SpaceBetween,
         verticalAlignment = Alignment.CenterVertically,
@@ -583,7 +600,7 @@ private fun RowScope.SwitchTile(labelResId: Int, checked: Boolean, onCheckedChan
             text = stringResource(id = labelResId),
             modifier = Modifier.weight(1f)
         )
-        Switch(checked = checked, onCheckedChange = onCheckedChange)
+        Switch(checked = checked, enabled = enabled, onCheckedChange = onCheckedChange)
     }
 }
 

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsViewModel.kt

@@ -127,7 +127,10 @@ class SettingsViewModel(
             is SettingsAction.ToggleUpdate -> settingsRepo.updateOtherSettings { it.copy(stateOfAutoUpdate = action.value) }
             is SettingsAction.ToggleSweep -> settingsRepo.updateOtherSettings { it.copy(stateOfSweep = action.value) }
             is SettingsAction.ToggleSensor -> settingsRepo.updateOtherSettings { it.copy(stateOfSensors = action.value) }
-            is SettingsAction.ToggleLightTheme -> settingsRepo.updateOtherSettings { it.copy(stateOfLightTheme = action.value) }
+            is SettingsAction.ToggleLightTheme -> settingsRepo.updateOtherSettings {
+                // Night filter (red-only overlay) is incompatible with the light theme, so turn it off.
+                it.copy(stateOfLightTheme = action.value, stateOfNightMode = if (action.value) false else it.stateOfNightMode)
+            }
             is SettingsAction.ToggleNightMode -> settingsRepo.updateOtherSettings { it.copy(stateOfNightMode = action.value) }
             is SettingsAction.SetRadarCompassOffset -> settingsRepo.updateOtherSettings { it.copy(radarCompassOffset = action.value) }
             is SettingsAction.SetRadarCompassOffsetElev -> settingsRepo.updateOtherSettings { it.copy(radarCompassOffsetElev = action.value) }