Merge remote-tracking branch 'origin/release/v2.16.0' into feat/recurrence-exdate

# Conflicts:
#	app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditScreen.kt

app/src/main/AndroidManifest.xml

@@ -63,10 +63,9 @@
             android:exported="true"
             android:launchMode="singleTop"
             android:windowSoftInputMode="adjustResize">
-            <intent-filter>
-                <action android:name="android.intent.action.MAIN" />
-                <category android:name="android.intent.category.LAUNCHER" />
-            </intent-filter>
+            <!-- The MAIN/LAUNCHER entry (the launcher icon + its label) lives on
+                 the two <activity-alias> below, so the app name can be switched at
+                 runtime (issue #44). MainActivity keeps every other filter. -->
 
             <!-- Be selectable as the system calendar app. Android has no API for
                  an app to make itself the default, so registering the filters
@@ -165,11 +164,47 @@
                 <data android:mimeType="vnd.android.cursor.item/event" />
             </intent-filter>
 
-            <!-- Launcher long-press shortcuts (e.g. "New event"). -->
+        </activity>
+
+        <!-- Launcher entry for MainActivity, split into two aliases so the app's
+             launcher name can be switched at runtime between "Calendula" and
+             "Calendar" (issue #44). Exactly one is enabled at a time; the app
+             flips them via PackageManager.setComponentEnabledSetting
+             (LauncherNameManager). The shortcuts meta-data lives here, not on
+             MainActivity, because static shortcuts are published by whichever
+             component owns the MAIN/LAUNCHER filter. -->
+        <activity-alias
+            android:name=".DefaultNameAlias"
+            android:enabled="true"
+            android:exported="true"
+            android:icon="@mipmap/ic_launcher"
+            android:label="@string/app_name"
+            android:roundIcon="@mipmap/ic_launcher_round"
+            android:targetActivity=".MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
             <meta-data
                 android:name="android.app.shortcuts"
                 android:resource="@xml/shortcuts" />
-        </activity>
+        </activity-alias>
+        <activity-alias
+            android:name=".CalendarNameAlias"
+            android:enabled="false"
+            android:exported="true"
+            android:icon="@mipmap/ic_launcher"
+            android:label="@string/app_name_calendar_alias"
+            android:roundIcon="@mipmap/ic_launcher_round"
+            android:targetActivity=".MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+            <meta-data
+                android:name="android.app.shortcuts"
+                android:resource="@xml/shortcuts" />
+        </activity-alias>
 
         <!-- Standalone surface for a captured crash report. MainActivity routes
              here on a startup crash-loop, so it stays clear of the app's Hilt

app/src/main/java/de/jeanlucmakiola/calendula/data/appname/LauncherNameManager.kt

@@ -0,0 +1,109 @@
+package de.jeanlucmakiola.calendula.data.appname
+
+import android.content.ComponentName
+import android.content.Context
+import android.content.pm.PackageManager
+import dagger.hilt.android.qualifiers.ApplicationContext
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/** The launcher label the app shows for itself (issue #44). */
+enum class LauncherName { CALENDULA, CALENDAR }
+
+/** The two launcher aliases declared in the manifest. */
+enum class LauncherAlias { DEFAULT, CALENDAR }
+
+/** One component-enable change in a [aliasWritePlan]. */
+data class AliasStateChange(val alias: LauncherAlias, val enabled: Boolean)
+
+/**
+ * Interpret the `CalendarNameAlias` component-enabled state as a [LauncherName].
+ * Only [PackageManager.COMPONENT_ENABLED_STATE_ENABLED] means the "Calendar"
+ * name is active; `DEFAULT` (never toggled) and `DISABLED` both resolve to the
+ * manifest default, "Calendula".
+ */
+fun launcherNameFor(calendarAliasState: Int): LauncherName =
+    if (calendarAliasState == PackageManager.COMPONENT_ENABLED_STATE_ENABLED) {
+        LauncherName.CALENDAR
+    } else {
+        LauncherName.CALENDULA
+    }
+
+/**
+ * The ordered enable/disable steps to switch the launcher name to [target].
+ * Always **enables the target alias first, then disables the other** — the two
+ * `setComponentEnabledSetting` calls are not atomic, and this ordering means the
+ * only transient the launcher can observe is a harmless two-entry state, never a
+ * zero-entry one (which would briefly drop the app from the launcher).
+ */
+fun aliasWritePlan(target: LauncherName): List<AliasStateChange> = when (target) {
+    LauncherName.CALENDAR -> listOf(
+        AliasStateChange(LauncherAlias.CALENDAR, enabled = true),
+        AliasStateChange(LauncherAlias.DEFAULT, enabled = false),
+    )
+    LauncherName.CALENDULA -> listOf(
+        AliasStateChange(LauncherAlias.DEFAULT, enabled = true),
+        AliasStateChange(LauncherAlias.CALENDAR, enabled = false),
+    )
+}
+
+/**
+ * Switches the app's launcher label between "Calendula" and "Calendar" by
+ * enabling/disabling the two `<activity-alias>` components (issue #44). The
+ * component-enabled state is the single source of truth — there is no persisted
+ * preference — so [current] reads it straight from [PackageManager] and the two
+ * always agree.
+ *
+ * The decision logic lives in the pure [launcherNameFor] / [aliasWritePlan]
+ * functions above (JVM-tested); this class is only the thin framework seam.
+ */
+@Singleton
+class LauncherNameManager @Inject constructor(
+    @ApplicationContext private val context: Context,
+) {
+    private val packageManager: PackageManager get() = context.packageManager
+
+    // The class portion is namespace-qualified (suffix-free), the package portion
+    // is the applicationId (which carries the .debug / .releasetest suffix). The
+    // manifest's ".CalendarNameAlias" resolves its class against the namespace, so
+    // the real component is <namespace>.CalendarNameAlias registered under the
+    // suffixed applicationId. Do NOT use ComponentName(context, ".CalendarNameAlias")
+    // — its leading-dot form prepends the applicationId to the class too, producing
+    // "<appId>.CalendarNameAlias" and failing on every debug / releaseTest build.
+    private fun component(alias: LauncherAlias): ComponentName {
+        val simpleName = when (alias) {
+            LauncherAlias.DEFAULT -> "DefaultNameAlias"
+            LauncherAlias.CALENDAR -> "CalendarNameAlias"
+        }
+        return ComponentName(context.packageName, "$NAMESPACE.$simpleName")
+    }
+
+    /** The launcher name currently in effect. */
+    fun current(): LauncherName =
+        launcherNameFor(packageManager.getComponentEnabledSetting(component(LauncherAlias.CALENDAR)))
+
+    /** Switch the launcher name to [name] (no-op cost if already active). */
+    fun set(name: LauncherName) {
+        for (change in aliasWritePlan(name)) {
+            val state = if (change.enabled) {
+                PackageManager.COMPONENT_ENABLED_STATE_ENABLED
+            } else {
+                PackageManager.COMPONENT_ENABLED_STATE_DISABLED
+            }
+            packageManager.setComponentEnabledSetting(
+                component(change.alias),
+                state,
+                PackageManager.DONT_KILL_APP,
+            )
+        }
+    }
+
+    private companion object {
+        /**
+         * The app's namespace (R-class package) — NOT `applicationId`, which
+         * carries the build-type suffix. Kept in sync with `namespace` in
+         * `app/build.gradle.kts`.
+         */
+        const val NAMESPACE = "de.jeanlucmakiola.calendula"
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/EventWriteMapper.kt

@@ -6,9 +6,11 @@ import de.jeanlucmakiola.calendula.domain.Availability
 import de.jeanlucmakiola.calendula.domain.EventForm
 import kotlinx.datetime.toJavaLocalDate
 import kotlinx.datetime.toJavaLocalDateTime
+import java.time.Duration
 import java.time.Instant
 import java.time.ZoneId
 import java.time.ZoneOffset
+import java.time.LocalDateTime as JavaLocalDateTime
 
 /** Provider-ready DTSTART / DTEND / EVENT_TIMEZONE for an event write. */
 internal data class EventWriteTimes(
@@ -35,7 +37,7 @@ internal fun EventForm.toWriteTimes(zone: ZoneId): EventWriteTimes = if (isAllDa
         timezone = "UTC",
     )
 } else {
-    val writeZone = timezone?.let { runCatching { ZoneId.of(it) }.getOrNull() } ?: zone
+    val writeZone = writeZone(zone)
     EventWriteTimes(
         dtStartMillis = start.toJavaLocalDateTime().atZone(writeZone).toInstant().toEpochMilli(),
         dtEndMillis = end.toJavaLocalDateTime().atZone(writeZone).toInstant().toEpochMilli(),
@@ -43,6 +45,30 @@ internal fun EventForm.toWriteTimes(zone: ZoneId): EventWriteTimes = if (isAllDa
     )
 }
 
+/**
+ * The zone this form's DTSTART is expressed in: UTC for an all-day event (the
+ * provider's date anchor), otherwise the form's own pinned zone, falling back to
+ * [deviceZone] when it doesn't pin one or pins something the tz database can't
+ * parse.
+ */
+private fun EventForm.writeZone(deviceZone: ZoneId): ZoneId = if (isAllDay) {
+    ZoneOffset.UTC
+} else {
+    timezone?.let { runCatching { ZoneId.of(it) }.getOrNull() } ?: deviceZone
+}
+
+/**
+ * The form's start as a bare wall-clock value — what the user sees on the form,
+ * stripped of any zone. All-day events use their date's midnight rather than
+ * [EventForm.start]'s placeholder time-of-day, which exists only so switching the
+ * event back to timed has something to show.
+ */
+private fun EventForm.anchorLocal(): JavaLocalDateTime = if (isAllDay) {
+    start.date.toJavaLocalDate().atStartOfDay()
+} else {
+    start.toJavaLocalDateTime()
+}
+
 /**
  * RFC 2445 duration for a recurring event's row (the provider requires
  * DURATION instead of DTEND when an RRULE is set): whole days for all-day
@@ -109,10 +135,12 @@ internal fun buildEventInsertValues(
  * Time fields travel together (the provider validates them as a unit):
  * - unchanged times, all-day flag and rrule → no time columns at all;
  * - non-recurring result → DTSTART/DTEND, DURATION and RRULE cleared;
- * - recurring result → the *series* DTSTART moves by the same delta the user
- *   applied to the displayed occurrence ([seriesDtStartMillis] is the row's
- *   current DTSTART), DURATION replaces DTEND, RRULE is written. This keeps
- *   past occurrences intact when someone edits a later occurrence's time.
+ * - recurring result → the *series* DTSTART moves by the same **wall-clock**
+ *   shift the user applied to the displayed occurrence and is re-resolved in the
+ *   event's zone ([seriesDtStartMillis] is the row's current DTSTART), DURATION
+ *   replaces DTEND, RRULE is written. This keeps past occurrences intact when
+ *   someone edits a later occurrence's time, and keeps the anchor's time-of-day
+ *   stable across a DST boundary or a zone change between the two.
  */
 internal fun buildEventUpdateValues(
     original: EventForm,
@@ -158,8 +186,23 @@ internal fun buildEventUpdateValues(
         put(CalendarContract.Events.RRULE, null)
         put(CalendarContract.Events.DURATION, null)
     } else {
-        val startDelta = newTimes.dtStartMillis - original.toWriteTimes(zone).dtStartMillis
-        put(CalendarContract.Events.DTSTART, seriesDtStartMillis + startDelta)
+        // Move the series anchor by the *wall-clock* shift the user applied to the
+        // displayed occurrence, then re-resolve it in the event's (possibly new)
+        // zone — never by a millisecond delta. An instant delta silently bakes in
+        // the offset that happened to apply on the edited occurrence's date, which
+        // is a different offset from the series anchor's whenever a DST boundary
+        // sits between them, or whenever the zone itself changed. Working in wall
+        // clock keeps "09:00" meaning 09:00 at both ends.
+        val seriesLocal = Instant.ofEpochMilli(seriesDtStartMillis)
+            .atZone(original.writeZone(zone)).toLocalDateTime()
+        val wallClockShift = Duration.between(original.anchorLocal(), updated.anchorLocal())
+        val shifted = seriesLocal.plus(wallClockShift)
+        // An all-day series anchor must sit on a UTC midnight. A pure day move
+        // already lands there (both ends are midnights), but *switching* a
+        // recurring event to all-day shifts by a time-of-day too, so snap.
+        val newSeriesLocal = if (updated.isAllDay) shifted.toLocalDate().atStartOfDay() else shifted
+        val newSeriesStart = newSeriesLocal.atZone(updated.writeZone(zone))
+        put(CalendarContract.Events.DTSTART, newSeriesStart.toInstant().toEpochMilli())
         put(CalendarContract.Events.DTEND, null)
         put(CalendarContract.Events.RRULE, updated.rrule)
         put(CalendarContract.Events.DURATION, newTimes.toRfc2445Duration(updated.isAllDay))

app/src/main/java/de/jeanlucmakiola/calendula/domain/TimeZoneCatalog.kt

@@ -31,8 +31,33 @@ data class TimeZoneOption(
 
     /** The leading segment ("Europe/Berlin" -> "Europe"); empty for bare ids like "UTC". */
     val region: String get() = id.substringBeforeLast('/', missingDelimiterValue = "")
+
+    /**
+     * The four fields [filterTimeZones] matches on, normalized once here rather
+     * than per query. Normalizing is not cheap — NFD decomposition plus a combining-
+     * mark strip — and a search re-examines every option on every keystroke, so
+     * doing it at construction turns ~2400 normalizations per character into a few
+     * hundred plain `startsWith`/`contains` calls.
+     *
+     * Declared in the class body, so it stays out of `equals`/`hashCode`/`copy`:
+     * it is derived state, and two options with the same id are the same option.
+     */
+    internal val searchKeys: TimeZoneSearchKeys = TimeZoneSearchKeys(
+        city = city.normalizeForSearch(),
+        id = id.normalizeForSearch(),
+        displayName = displayName.normalizeForSearch(),
+        shortName = shortName.normalizeForSearch(),
+    )
 }
 
+/** Pre-normalized match targets for one [TimeZoneOption]. */
+internal data class TimeZoneSearchKeys(
+    val city: String,
+    val id: String,
+    val displayName: String,
+    val shortName: String,
+)
+
 private fun optionFor(
     zone: ZoneId,
     locale: Locale,
@@ -87,9 +112,13 @@ private fun resolveAbbreviation(
 private fun String.looksLikeOffset(): Boolean = this == "UTC" || startsWith("GMT")
 
 /**
- * Every zone the JVM knows, resolved at [at]. This is ~600 entries, so build it
- * once and filter the result rather than rebuilding per keystroke. [regionOf]
- * (see [resolveAbbreviation]) supplies the zone's region for the abbreviation.
+ * Every zone the JVM knows, resolved at [at]. [regionOf] (see
+ * [resolveAbbreviation]) supplies the zone's region for the abbreviation.
+ *
+ * This is ~600 entries, each costing a localized display name plus up to two ICU
+ * short-name lookups, so it is **not** cheap enough for the main thread — build
+ * it off-thread once and filter the result with [filterTimeZones] rather than
+ * rebuilding per keystroke.
  *
  * Bare three-letter ids ("EST", "CST6CDT") and the legacy SystemV tree are
  * dropped: they're aliases the tz database keeps for compatibility, they'd
@@ -154,18 +183,15 @@ fun filterTimeZones(options: List<TimeZoneOption>, query: String): List<TimeZone
     if (needle.isEmpty()) return options
     return options
         .mapNotNull { option ->
-            val city = option.city.normalizeForSearch()
-            val id = option.id.normalizeForSearch()
-            val name = option.displayName.normalizeForSearch()
-            val abbrev = option.shortName.normalizeForSearch()
+            val keys = option.searchKeys
             val rank = when {
-                city.startsWith(needle) -> 0
-                abbrev == needle -> 1
-                name.startsWith(needle) -> 2
-                abbrev.startsWith(needle) -> 3
-                city.contains(needle) -> 4
-                id.contains(needle) -> 5
-                name.contains(needle) -> 6
+                keys.city.startsWith(needle) -> 0
+                keys.shortName == needle -> 1
+                keys.displayName.startsWith(needle) -> 2
+                keys.shortName.startsWith(needle) -> 3
+                keys.city.contains(needle) -> 4
+                keys.id.contains(needle) -> 5
+                keys.displayName.contains(needle) -> 6
                 else -> return@mapNotNull null
             }
             rank to option
@@ -174,6 +200,9 @@ fun filterTimeZones(options: List<TimeZoneOption>, query: String): List<TimeZone
         .map { it.second }
 }
 
+/** Unicode combining marks — what NFD decomposition leaves an accent as. */
+private val COMBINING_MARKS = Regex("\\p{Mn}+")
+
 /**
  * Lowercased, accent-stripped, underscores and slashes flattened to spaces, so
  * a query types the way a place is spoken rather than the way the tz database
@@ -181,7 +210,7 @@ fun filterTimeZones(options: List<TimeZoneOption>, query: String): List<TimeZone
  */
 private fun String.normalizeForSearch(): String =
     Normalizer.normalize(this, Normalizer.Form.NFD)
-        .replace(Regex("\\p{Mn}+"), "")
+        .replace(COMBINING_MARKS, "")
         .replace('_', ' ')
         .replace('/', ' ')
         .lowercase(Locale.ROOT)

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaScreen.kt

@@ -89,7 +89,9 @@ import kotlinx.datetime.toLocalDateTime
 import kotlin.time.Instant
 import java.util.Locale
 
-private val zone = TimeZone.currentSystemDefault()
+// No file-level zone constant here on purpose: it would be fixed for the process
+// lifetime and drift from the zone AgendaViewModel groups in after a device
+// time-zone change. The zone travels on AgendaUiState.Success instead.
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -332,6 +334,7 @@ private fun AgendaContent(
                 AgendaList(
                     days = days,
                     today = state.today,
+                    zone = state.zone,
                     dimPast = pastDisplay == PastEventDisplay.DIM,
                     now = now,
                     onEventClick = onEventClick,
@@ -348,6 +351,7 @@ private fun AgendaContent(
 private fun AgendaList(
     days: List<AgendaDay>,
     today: LocalDate,
+    zone: TimeZone,
     dimPast: Boolean,
     now: Instant,
     onEventClick: (EventInstance) -> Unit,
@@ -379,6 +383,7 @@ private fun AgendaList(
                     AgendaEventRow(
                         event = event,
                         day = day.date,
+                        zone = zone,
                         position = positionOf(index, day.events.size),
                         dimmed = dimPast && event.hasEnded(now),
                         modifier = animateItemMotion(),
@@ -458,6 +463,7 @@ private fun AgendaEmptyDayRow(onClick: () -> Unit) {
 private fun AgendaEventRow(
     event: EventInstance,
     day: LocalDate,
+    zone: TimeZone,
     position: Position,
     dimmed: Boolean,
     modifier: Modifier = Modifier,
@@ -469,7 +475,7 @@ private fun AgendaEventRow(
     GroupedRow(
         modifier = if (dimmed) modifier.alpha(EventDimAlpha) else modifier,
         title = title,
-        summary = agendaTimeSummary(event, day),
+        summary = agendaTimeSummary(event, day, zone),
         position = position,
         minHeight = 64.dp,
         leading = {
@@ -575,25 +581,34 @@ private fun agendaDayLabel(date: LocalDate, today: LocalDate): String {
  * An all-day multi-day event is simply "All day" on every day it covers.
  */
 @Composable
-private fun agendaTimeSummary(event: EventInstance, day: LocalDate): String {
+private fun agendaTimeSummary(event: EventInstance, day: LocalDate, zone: TimeZone): String {
     val is24Hour = LocalUse24HourFormat.current
     val locale = currentLocale()
 
     val time = when (val label = agendaTimeLabel(event, day, zone)) {
         AgendaTimeLabel.AllDay -> stringResource(R.string.event_detail_all_day)
-        is AgendaTimeLabel.Starts ->
-            stringResource(R.string.agenda_span_starts, formatTime(label.start, is24Hour, locale))
-        is AgendaTimeLabel.Ends ->
-            stringResource(R.string.agenda_span_ends, formatTime(label.end, is24Hour, locale))
-        is AgendaTimeLabel.Range ->
-            "${formatTime(label.start, is24Hour, locale)} – ${formatTime(label.end, is24Hour, locale)}"
+        is AgendaTimeLabel.Starts -> stringResource(
+            R.string.agenda_span_starts,
+            formatTime(label.start, zone, is24Hour, locale),
+        )
+        is AgendaTimeLabel.Ends -> stringResource(
+            R.string.agenda_span_ends,
+            formatTime(label.end, zone, is24Hour, locale),
+        )
+        is AgendaTimeLabel.Range -> "${formatTime(label.start, zone, is24Hour, locale)} – " +
+            formatTime(label.end, zone, is24Hour, locale)
     }
 
     val location = event.location?.takeIf { it.isNotBlank() }
     return if (location != null) "$time · $location" else time
 }
 
-private fun formatTime(instant: Instant, is24Hour: Boolean, locale: Locale): String {
+private fun formatTime(
+    instant: Instant,
+    zone: TimeZone,
+    is24Hour: Boolean,
+    locale: Locale,
+): String {
     val t = instant.toLocalDateTime(zone).time
     return formatTimeOfDay(t.hour, t.minute, is24Hour, locale)
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaUiState.kt

@@ -160,5 +160,12 @@ sealed interface AgendaUiState {
         val rangeEnd: LocalDate,
         /** Whether to show the top range bar — header + switcher (toggle, on by default). */
         val showRangeBar: Boolean,
+        /**
+         * The zone [days] were grouped in. Carried in the state rather than
+         * re-read by the screen so labelling and grouping cannot disagree: an
+         * event's "Starts …/Ends …/All day" line is only correct relative to the
+         * same zone that decided which day it was filed under.
+         */
+        val zone: TimeZone,
     ) : AgendaUiState
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaViewModel.kt

@@ -169,6 +169,7 @@ class AgendaViewModel @Inject constructor(
             rangeIsOverride = params.rangeIsOverride,
             rangeEnd = rangeEnd,
             showRangeBar = params.showRangeBar,
+            zone = zone,
         )
     }
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarTitle.kt

@@ -16,13 +16,19 @@ import java.util.Locale
  * sits directly above a grid that already says which year it is, and the year's
  * *absence* is itself the signal that you're in the current one — it appears the
  * moment you page out of it, which is when it starts carrying information.
+ *
+ * [forceYear] overrides that for titles whose [date] does not tell the whole
+ * story — a week view's title names only the month its *first* day falls in, so
+ * a week straddling New Year must still show the year even though [date] is in
+ * [currentYear].
  */
 fun formatCalendarTitle(
     date: java.time.LocalDate,
     locale: Locale,
     currentYear: Int,
     skeleton: String,
+    forceYear: Boolean = false,
 ): String {
-    val fields = if (date.year == currentYear) skeleton else skeleton + "y"
+    val fields = if (date.year == currentYear && !forceYear) skeleton else skeleton + "y"
     return localizedDateFormatter(locale, fields).format(date)
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/TimeZonePicker.kt

@@ -20,6 +20,7 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
@@ -34,6 +35,7 @@ import androidx.compose.ui.unit.dp
 import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.domain.TimeZoneOption
 import de.jeanlucmakiola.calendula.domain.filterTimeZones
+import de.jeanlucmakiola.calendula.domain.timeZoneOptionOf
 import de.jeanlucmakiola.calendula.domain.timeZoneOptions
 import de.jeanlucmakiola.calendula.domain.zoneDescriptor
 import de.jeanlucmakiola.floret.components.FullScreenPicker
@@ -43,6 +45,8 @@ import de.jeanlucmakiola.floret.components.Position
 import de.jeanlucmakiola.floret.components.SelectedCheck
 import de.jeanlucmakiola.floret.components.positionOf
 import de.jeanlucmakiola.floret.locale.currentLocale
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
 
 /**
  * Full-screen zone picker: a query field over every zone the JVM knows, with the
@@ -64,14 +68,28 @@ fun TimeZonePickerDialog(
     onDismiss: () -> Unit,
 ) {
     var query by rememberSaveable { mutableStateOf("") }
-    // ~600 zones, each resolving a localized name and a DST-aware offset: build
-    // once per open, then filter the result per keystroke.
     val locale = currentLocale()
-    val allZones = remember(locale) { timeZoneOptions(locale, regionOf = ::icuTimeZoneRegion) }
+    // ~600 zones, each resolving a localized name and up to two ICU short names:
+    // far too much to run inside composition, so build it on a worker and let the
+    // list fill in a frame later. Filtering the built catalogue is cheap (its
+    // search keys are pre-normalized), so that stays here.
+    val allZones by produceState(initialValue = emptyList<TimeZoneOption>(), locale) {
+        value = withContext(Dispatchers.Default) {
+            timeZoneOptions(locale, regionOf = ::icuTimeZoneRegion)
+        }
+    }
     val matches = remember(allZones, query) { filterTimeZones(allZones, query) }
     val recentZones = remember(allZones, recents) {
         recents.mapNotNull { id -> allZones.firstOrNull { it.id == id } }
     }
+    // Resolved on its own rather than looked up in the catalogue: it's one zone,
+    // so it costs nothing, and the device row can then render complete on the
+    // first frame instead of showing a bare id until the catalogue lands.
+    val deviceSummary = remember(deviceZoneId, locale) {
+        timeZoneOptionOf(deviceZoneId, locale, regionOf = ::icuTimeZoneRegion)
+            ?.let { zoneDescriptor(it) }
+            ?: deviceZoneId
+    }
     val searching = query.isNotBlank()
 
     fun choose(zoneId: String?) {
@@ -97,7 +115,7 @@ fun TimeZonePickerDialog(
                 item(key = "device") {
                     GroupedRow(
                         title = stringResource(R.string.event_edit_timezone_device),
-                        summary = zoneSummary(deviceZoneId, allZones),
+                        summary = deviceSummary,
                         position = Position.Alone,
                         selected = selected == null,
                         leading = { Icon(Icons.Default.Public, contentDescription = null) },
@@ -130,7 +148,10 @@ fun TimeZonePickerDialog(
                 }
             }
 
-            if (searching && matches.isEmpty()) {
+            // allZones.isNotEmpty() gates this: until the catalogue lands there is
+            // simply nothing to match yet, and claiming "no time zone matches"
+            // for that frame would be wrong.
+            if (searching && matches.isEmpty() && allZones.isNotEmpty()) {
                 item(key = "empty") {
                     Text(
                         text = stringResource(R.string.event_edit_timezone_none, query),
@@ -244,9 +265,3 @@ private fun ZoneRow(
         onClick = onClick,
     )
 }
-
-/** "CET · GMT+01:00" for [zoneId], or the bare id if the catalogue lacks it. */
-private fun zoneSummary(zoneId: String, allZones: List<TimeZoneOption>): String =
-    allZones.firstOrNull { it.id == zoneId }
-        ?.let { zoneDescriptor(it) }
-        ?: zoneId

app/src/main/java/de/jeanlucmakiola/calendula/ui/detail/EventDetailScreen.kt

@@ -109,6 +109,7 @@ import de.jeanlucmakiola.calendula.ui.common.recurrenceText
 import de.jeanlucmakiola.calendula.ui.common.reminderLeadTimeLabel
 import kotlinx.coroutines.launch
 import kotlinx.datetime.TimeZone
+import kotlin.time.toJavaInstant
 import java.time.ZoneId
 import java.time.format.DateTimeFormatter
 import java.time.format.FormatStyle
@@ -463,8 +464,8 @@ private fun EventDetailContent(state: EventDetailUiState.Success, modifier: Modi
         // Same hierarchy as the When card above — the label carries the card,
         // the time sits small beneath it. The local time is the one the reader
         // acts on, so the original must stay quieter than it, not compete.
-        val foreignZone = remember(detail.eventTimezone, instance.isAllDay, locale) {
-            foreignTimeZone(detail.eventTimezone, instance.isAllDay, locale)
+        val foreignZone = remember(detail.eventTimezone, instance.isAllDay, instance.start, locale) {
+            foreignTimeZone(detail.eventTimezone, instance.isAllDay, locale, instance.start)
         }
         foreignZone?.let { zoneOption ->
             Spacer(Modifier.height(gap))
@@ -789,11 +790,26 @@ private fun reminderLeadText(reminder: Reminder): String = reminderLeadTimeLabel
  * pinned to a zone different from the device's — the cases where showing it
  * removes ambiguity. Null otherwise (all-day, device-zone, blank, or an id the
  * tz database doesn't know).
+ *
+ * Resolved *at [at]*, the event's own start, not at "now": the abbreviation and
+ * offset both move with DST, and the card prints them next to the event's time.
+ * Resolving at now would label a July event "CET · 10:00 AM" when read in
+ * January — an abbreviation that contradicts the time beside it.
  */
-private fun foreignTimeZone(tz: String?, isAllDay: Boolean, locale: Locale): TimeZoneOption? {
+private fun foreignTimeZone(
+    tz: String?,
+    isAllDay: Boolean,
+    locale: Locale,
+    at: Instant,
+): TimeZoneOption? {
     if (isAllDay || tz.isNullOrBlank()) return null
     if (tz == ZoneId.systemDefault().id) return null
-    return timeZoneOptionOf(tz, locale, regionOf = ::icuTimeZoneRegion)
+    return timeZoneOptionOf(
+        tz,
+        locale,
+        at = at.toJavaInstant(),
+        regionOf = ::icuTimeZoneRegion,
+    )
 }
 
 /** Wrap http(s) URLs in [text] as tappable links tinted [linkColor]. */

app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditScreen.kt

@@ -47,7 +47,6 @@ import androidx.compose.material.icons.filled.Person
 import androidx.compose.material.icons.filled.PersonAdd
 import androidx.compose.material.icons.filled.Place
 import androidx.compose.material.icons.filled.Public
-import androidx.compose.material.icons.filled.Public
 import androidx.compose.material.icons.filled.Repeat
 import androidx.compose.material.icons.filled.Schedule
 import androidx.compose.material.icons.filled.Tune
@@ -165,8 +164,10 @@ import kotlinx.datetime.TimeZone
 import kotlinx.datetime.isoDayNumber
 import kotlinx.datetime.toJavaDayOfWeek
 import kotlinx.datetime.toJavaLocalDate
+import kotlinx.datetime.toInstant
 import kotlinx.datetime.toJavaLocalTime
 import kotlinx.datetime.toLocalDateTime
+import kotlin.time.toJavaInstant
 import java.time.ZoneId
 import java.time.format.DateTimeFormatter
 import java.time.format.FormatStyle
@@ -684,7 +685,13 @@ private fun EventEditContent(
             // whoever is reading it. Spell the local equivalent out rather than
             // leaving the user to do the offset arithmetic. Absent (null) unless
             // the event is pinned somewhere other than here.
-            form.timesIn(TimeZone.currentSystemDefault())?.let { (localStart, localEnd) ->
+            // Keyed rather than recomputed: this sits in the same Column as the
+            // title field, so it would otherwise re-parse the zone on every
+            // keystroke.
+            val localTimes = remember(form.timezone, form.start, form.end, form.isAllDay) {
+                form.timesIn(TimeZone.currentSystemDefault())
+            }
+            localTimes?.let { (localStart, localEnd) ->
                 Spacer(Modifier.height(2.dp))
                 Text(
                     text = stringResource(
@@ -742,8 +749,20 @@ private fun EventEditContent(
                     verticalAlignment = Alignment.CenterVertically,
                     modifier = Modifier.fillMaxWidth(),
                 ) {
-                    val pinned = remember(form.timezone, locale) {
-                        form.timezone?.let { timeZoneOptionOf(it, locale, regionOf = ::icuTimeZoneRegion) }
+                    // Resolved at the event's own start, not at "now": the
+                    // abbreviation and offset shown ("CEST · GMT+02:00") must be
+                    // the ones that apply when the event actually happens.
+                    val pinned = remember(form.timezone, form.start, locale) {
+                        form.timezone
+                            ?.let { id -> runCatching { id to TimeZone.of(id) }.getOrNull() }
+                            ?.let { (id, zone) ->
+                                timeZoneOptionOf(
+                                    id,
+                                    locale,
+                                    at = form.start.toInstant(zone).toJavaInstant(),
+                                    regionOf = ::icuTimeZoneRegion,
+                                )
+                            }
                     }
                     Column(modifier = Modifier.weight(1f)) {
                         Text(

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsScreen.kt

@@ -23,6 +23,8 @@ import androidx.compose.animation.slideInHorizontally
 import androidx.compose.animation.slideOutHorizontally
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -42,6 +44,7 @@ import androidx.compose.material.icons.automirrored.filled.KeyboardArrowRight
 import androidx.compose.material.icons.filled.BugReport
 import androidx.compose.material.icons.filled.Cake
 import androidx.compose.material.icons.filled.CalendarMonth
+import androidx.compose.material.icons.filled.Check
 import androidx.compose.material.icons.filled.Dashboard
 import androidx.compose.material.icons.filled.DragHandle
 import androidx.compose.material.icons.filled.SwapVert
@@ -74,6 +77,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.colorResource
@@ -92,6 +96,7 @@ import androidx.lifecycle.LifecycleEventObserver
 import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.data.appname.LauncherName
 import de.jeanlucmakiola.calendula.data.contacts.hasContactsPermission
 import de.jeanlucmakiola.calendula.data.prefs.PastEventDisplay
 import de.jeanlucmakiola.floret.reminders.ReminderOverride
@@ -487,8 +492,10 @@ private fun AppearanceScreen(
     var showPastEvents by remember { mutableStateOf(false) }
     var showBrandFont by remember { mutableStateOf(false) }
     var showPlainFont by remember { mutableStateOf(false) }
+    var showAppName by remember { mutableStateOf(false) }
 
     val fonts by viewModel.fontState.collectAsStateWithLifecycle()
+    val launcherName by viewModel.launcherName.collectAsStateWithLifecycle()
     // A picked file that didn't parse as a font: tell the user and keep the old choice.
     val context = LocalContext.current
     val importFailedMessage = stringResource(R.string.settings_font_import_failed)
@@ -679,8 +686,58 @@ private fun AppearanceScreen(
             },
             onClick = { viewModel.setAgendaShowRangeBar(!state.agendaShowRangeBar) },
         )
+
+        Spacer(Modifier.height(16.dp))
+
+        // App name — chooses the launcher label between "Calendula" and "Calendar"
+        // (issue #44). Own group: it's a launcher/system concern, not calendar
+        // formatting. A sub-page chooser (not a switch), matching the app's other
+        // "choose one" settings and leaving room for more names later.
+        GroupedRow(
+            title = stringResource(R.string.settings_app_name),
+            summary = launcherNameLabel(launcherName),
+            position = Position.Alone,
+            onClick = { showAppName = true },
+        )
     }
 
+    if (showAppName) {
+        FullScreenPicker(
+            title = stringResource(R.string.settings_app_name),
+            onDismiss = { showAppName = false },
+            predictiveBack = true,
+        ) {
+            // Show both names as launcher-mark previews so the user sees what
+            // they'd switch to, not just the current state. Tapping applies
+            // immediately and highlights — the picker stays open so the change is
+            // visible; back exits.
+            Text(
+                text = stringResource(R.string.settings_app_name_summary),
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                textAlign = TextAlign.Center,
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(horizontal = 24.dp),
+            )
+            Spacer(Modifier.height(24.dp))
+            Row(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(horizontal = 16.dp),
+                horizontalArrangement = Arrangement.spacedBy(16.dp),
+            ) {
+                LauncherName.entries.forEach { option ->
+                    AppNameOptionCard(
+                        name = option,
+                        selected = launcherName == option,
+                        onClick = { viewModel.setLauncherName(option) },
+                        modifier = Modifier.weight(1f),
+                    )
+                }
+            }
+        }
+    }
     if (showTheme) {
         OptionPicker(
             title = stringResource(R.string.settings_theme),
@@ -1698,6 +1755,98 @@ private fun openUrl(context: Context, url: String) {
     runCatching { context.startActivity(intent) }
 }
 
+/** The display name for a launcher-label choice (issue #44). */
+@Composable
+private fun launcherNameLabel(name: LauncherName): String = stringResource(
+    when (name) {
+        LauncherName.CALENDULA -> R.string.app_name
+        LauncherName.CALENDAR -> R.string.app_name_calendar_alias
+    },
+)
+
+/**
+ * One selectable launcher-name preview in the App name picker (issue #44): the
+ * app's launcher mark over the name, framed as a card. The active one carries a
+ * primary border, a tinted container and a check; tapping selects it. The mark
+ * is the same for both — only the label changes — so the card previews exactly
+ * what the home screen will read.
+ */
+@Composable
+private fun AppNameOptionCard(
+    name: LauncherName,
+    selected: Boolean,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val shape = RoundedCornerShape(24.dp)
+    val borderColor = if (selected) {
+        MaterialTheme.colorScheme.primary
+    } else {
+        MaterialTheme.colorScheme.outlineVariant
+    }
+    val containerColor = if (selected) {
+        MaterialTheme.colorScheme.primaryContainer.copy(alpha = 0.4f)
+    } else {
+        MaterialTheme.colorScheme.surfaceContainerHigh
+    }
+    Column(
+        modifier = modifier
+            .clip(shape)
+            .background(containerColor)
+            .border(width = if (selected) 2.dp else 1.dp, color = borderColor, shape = shape)
+            .clickable(onClick = onClick)
+            .padding(vertical = 20.dp, horizontal = 16.dp),
+        horizontalAlignment = Alignment.CenterHorizontally,
+        verticalArrangement = Arrangement.spacedBy(12.dp),
+    ) {
+        // The adaptive launcher mark, reconstructed as a squircle (as in the
+        // onboarding BrandHero) so it renders identically everywhere.
+        Box(
+            modifier = Modifier
+                .size(64.dp)
+                .clip(RoundedCornerShape(18.dp))
+                .background(colorResource(R.color.ic_launcher_background)),
+        ) {
+            Image(
+                painter = painterResource(R.drawable.ic_launcher_foreground),
+                contentDescription = null,
+                modifier = Modifier.fillMaxSize(),
+            )
+        }
+        Text(
+            text = launcherNameLabel(name),
+            style = MaterialTheme.typography.titleMedium,
+            color = MaterialTheme.colorScheme.onSurface,
+            textAlign = TextAlign.Center,
+            maxLines = 1,
+        )
+        // Selection indicator: a filled check when active, an empty ring otherwise.
+        Box(
+            modifier = Modifier
+                .size(24.dp)
+                .clip(CircleShape)
+                .background(if (selected) MaterialTheme.colorScheme.primary else Color.Transparent)
+                .then(
+                    if (selected) {
+                        Modifier
+                    } else {
+                        Modifier.border(1.dp, MaterialTheme.colorScheme.outlineVariant, CircleShape)
+                    },
+                ),
+            contentAlignment = Alignment.Center,
+        ) {
+            if (selected) {
+                Icon(
+                    imageVector = Icons.Filled.Check,
+                    contentDescription = null,
+                    tint = MaterialTheme.colorScheme.onPrimary,
+                    modifier = Modifier.size(16.dp),
+                )
+            }
+        }
+    }
+}
+
 @Composable
 private fun themeLabel(mode: ThemeMode): String = stringResource(
     when (mode) {

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsViewModel.kt

@@ -10,6 +10,8 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import dagger.hilt.android.qualifiers.ApplicationContext
+import de.jeanlucmakiola.calendula.data.appname.LauncherName
+import de.jeanlucmakiola.calendula.data.appname.LauncherNameManager
 import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
 import de.jeanlucmakiola.calendula.data.contacts.SpecialDatesCalendarSpec
 import de.jeanlucmakiola.calendula.data.contacts.SpecialDatesScheduler
@@ -43,7 +45,9 @@ import de.jeanlucmakiola.calendula.widget.month.MonthWidget
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharedFlow
+import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.catch
@@ -62,6 +66,7 @@ class SettingsViewModel @Inject constructor(
     repository: CalendarRepository,
     private val specialDatesEngine: SpecialDatesSyncEngine,
     specialDatesSpec: SpecialDatesCalendarSpec,
+    private val launcherNameManager: LauncherNameManager,
     @IoDispatcher private val io: CoroutineDispatcher,
     @ApplicationContext private val appContext: Context,
 ) : ViewModel() {
@@ -202,6 +207,28 @@ class SettingsViewModel @Inject constructor(
         initialValue = AppFontSettings(),
     )
 
+    /**
+     * The launcher-label choice (issue #44). Backed by the manifest aliases'
+     * component-enabled state rather than a stored preference, so it's read
+     * imperatively via [LauncherNameManager] and held here in its own flow — the
+     * main settings combine is already at its arity limit and this isn't a
+     * DataStore flow anyway.
+     *
+     * Seeded with the manifest default and corrected off-thread rather than read
+     * in the initializer: `getComponentEnabledSetting` is a binder round-trip to
+     * system_server, and this ViewModel is constructed on the main thread while
+     * Settings is opening. The row it feeds is well below the fold, so the
+     * one-frame correction is never visible.
+     */
+    private val _launcherName = MutableStateFlow(LauncherName.CALENDULA)
+    val launcherName: StateFlow<LauncherName> = _launcherName.asStateFlow()
+
+    init {
+        viewModelScope.launch {
+            _launcherName.value = withContext(io) { launcherNameManager.current() }
+        }
+    }
+
     // Emitted when a picked font file couldn't be read as a font; the screen
     // surfaces it and the previous selection stays put.
     private val _fontImportFailed = MutableSharedFlow<Unit>(extraBufferCapacity = 1)
@@ -469,6 +496,22 @@ class SettingsViewModel @Inject constructor(
         viewModelScope.launch { prefs.setTodayButtonInToolbar(enabled) }
     }
 
+    /**
+     * Switch the launcher label between "Calendula" and "Calendar" (issue #44).
+     * The card highlights immediately, then settles on whatever the component
+     * state actually reports — the two `setComponentEnabledSetting` calls are
+     * binder round-trips, so they don't belong on the main thread either.
+     */
+    fun setLauncherName(name: LauncherName) {
+        _launcherName.value = name
+        viewModelScope.launch {
+            _launcherName.value = withContext(io) {
+                launcherNameManager.set(name)
+                launcherNameManager.current()
+            }
+        }
+    }
+
     fun setPastEventDisplay(mode: PastEventDisplay) {
         viewModelScope.launch {
             prefs.setPastEventDisplay(mode)

app/src/main/java/de/jeanlucmakiola/calendula/ui/week/WeekScreen.kt

@@ -880,13 +880,21 @@ private fun minToHm(min: Int, is24Hour: Boolean, locale: java.util.Locale): Stri
  * month of [weekStart] means a week straddling a boundary keeps the outgoing
  * month until it is fully gone — a week is seven contiguous days, so the earlier
  * month has a day in it exactly while [weekStart] is still inside it. That also
- * makes the title depend on nothing but [weekStart], so it cannot drift with the
- * direction you paged in from.
+ * makes the *month* depend on nothing but [weekStart], so it cannot drift with
+ * the direction you paged in from.
+ *
+ * The *year* is decided from the whole week, not just its start: a week running
+ * Dec 28 – Jan 3 has four of its seven visible columns in the new year, so
+ * "December" with no year would be actively misleading while the reader is
+ * looking straight at January dates.
  */
-private fun formatWeekTitle(weekStart: LocalDate, locale: Locale, currentYear: Int): String =
-    formatCalendarTitle(
+private fun formatWeekTitle(weekStart: LocalDate, locale: Locale, currentYear: Int): String {
+    val weekEnd = weekStart.plus(6, kotlinx.datetime.DateTimeUnit.DAY)
+    return formatCalendarTitle(
         date = java.time.LocalDate.of(weekStart.year, weekStart.month.ordinal + 1, 1),
         locale = locale,
         currentYear = currentYear,
         skeleton = "LLLL",
+        forceYear = weekEnd.year != weekStart.year,
     )
+}

app/src/main/java/de/jeanlucmakiola/calendula/widget/WidgetScale.kt

@@ -0,0 +1,70 @@
+package de.jeanlucmakiola.calendula.widget
+
+import androidx.compose.ui.unit.DpSize
+import androidx.compose.ui.unit.dp
+
+/**
+ * Size tiers a widget scales its typography and metrics across (#51).
+ *
+ * Shared by every Glance widget so the bucketing rule can't drift between them:
+ * each widget keeps its own metrics table, but they all agree on *when* a widget
+ * counts as compact, regular, large or extra-large. Both widgets already declare
+ * [androidx.glance.appwidget.SizeMode.Exact], so the composition sees the live
+ * size via `LocalSize.current` and passes it to [scaleFor].
+ *
+ * Kept in a pure, Glance-free file (only `compose.ui.unit`) so the bucketing is
+ * covered by plain JVM tests.
+ */
+internal enum class WidgetScale { COMPACT, REGULAR, LARGE, XLARGE }
+
+/**
+ * Chrome a widget spends before its first content row: outer vertical padding
+ * plus a header row and its spacer. Subtracted from the raw height so the height
+ * thresholds below talk about *usable* space rather than gross widget height.
+ */
+private val CHROME_HEIGHT = 60.dp
+
+/**
+ * Buckets a live widget size into a [WidgetScale] by **width**.
+ *
+ * Width is the right axis: it governs how much of a title fits on a row, so it's
+ * what should drive type size. Height only decides how many rows are visible — a
+ * tall, narrow widget wants *more events*, not bigger text — so it never raises
+ * the tier. It does act as a **cap**, though: a genuinely squashed widget is
+ * stepped back down so it can't keep oversized type in a sliver of space.
+ *
+ * The width thresholds are spread across the range a phone can actually produce
+ * (~180dp up to roughly the screen width) rather than over a theoretical range,
+ * so the tiers are reachable in practice. Calibrated on-device (Pixel / Nova): a
+ * compact 222dp-wide widget stays COMPACT (the app's baseline, unchanged) and a
+ * full-width 378dp one reaches LARGE. XLARGE is reserved for genuinely wide
+ * surfaces — tablets, foldables, landscape — where the extra size reads well.
+ *
+ * The height cap is deliberately generous: it exists to catch a widget squashed
+ * to one or two rows, **not** to gate ordinary placements. A full-width widget at
+ * the usual three cells tall (~270dp) must still reach the tier its width earned
+ * — that is exactly the resize #51 reports, and an aggressive cap would make the
+ * whole feature a no-op for it.
+ */
+internal fun scaleFor(size: DpSize): WidgetScale {
+    val byWidth = when {
+        size.width < 260.dp -> WidgetScale.COMPACT
+        size.width < 330.dp -> WidgetScale.REGULAR
+        size.width < 420.dp -> WidgetScale.LARGE
+        else -> WidgetScale.XLARGE
+    }
+    // Height can only ever pull the tier *down*, never push it up: a squashed
+    // widget would otherwise keep the big type its width earned and look absurd
+    // in the little space left. Keeping this a cap (rather than a second scaling
+    // axis) is what preserves "tall and narrow shows more events, not bigger
+    // text". Thresholds are usable height — roughly one, two and three rows of
+    // breathing room once the header is paid for.
+    val usable = size.height - CHROME_HEIGHT
+    val heightCap = when {
+        usable < 70.dp -> WidgetScale.COMPACT
+        usable < 130.dp -> WidgetScale.REGULAR
+        usable < 200.dp -> WidgetScale.LARGE
+        else -> WidgetScale.XLARGE
+    }
+    return minOf(byWidth, heightCap)
+}

app/src/main/java/de/jeanlucmakiola/calendula/widget/agenda/AgendaScale.kt

@@ -0,0 +1,150 @@
+package de.jeanlucmakiola.calendula.widget.agenda
+
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.TextUnit
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import de.jeanlucmakiola.calendula.widget.WidgetScale
+
+/**
+ * Horizontal layout constants for an agenda event row. These don't scale with the
+ * tier — a wider stripe or gap would eat title width, which is the thing the row
+ * is short of — but [TEXT_INDENT] is *derived* from them so the day header and
+ * the "nothing left today" line can never drift out of alignment with the event
+ * title column the way a hardcoded 19dp could.
+ */
+internal val ROW_H_PAD = 4.dp
+internal val STRIPE_WIDTH = 5.dp
+internal val STRIPE_GAP = 10.dp
+
+/** Left indent that lines non-event text up with the event title column. */
+internal val TEXT_INDENT = ROW_H_PAD + STRIPE_WIDTH + STRIPE_GAP
+
+/**
+ * The width band a *default* agenda placement can land in, per
+ * `app/src/main/res/xml/appwidget_info_agenda.xml` (`android:minWidth="180dp"`,
+ * `android:targetCellWidth="3"`). Measured at 222dp on a Pixel running Nova, but
+ * launcher cell grids vary, so the whole band — not one measured point — has to
+ * stay [WidgetScale.COMPACT] for the "default size is unchanged" promise of #51
+ * to hold. A test pins that.
+ *
+ * If the provider's `targetCellWidth` ever changes, this band and the first
+ * width threshold in [de.jeanlucmakiola.calendula.widget.scaleFor] must be
+ * revisited together.
+ */
+internal val AGENDA_DEFAULT_WIDTH_BAND = 180.dp..255.dp
+
+/**
+ * Every size the agenda widget varies by tier. Values that genuinely shouldn't
+ * grow (the horizontal row constants above, corner radii) stay constants rather
+ * than routing through here.
+ */
+internal data class AgendaMetrics(
+    val title: TextUnit,        // header "Upcoming"
+    val dayHeader: TextUnit,    // day label ("Today · …")
+    val eventTitle: TextUnit,   // event title line
+    val eventTime: TextUnit,    // time/location line
+    val placeholder: TextUnit,  // "no more events today" (#35)
+    val message: TextUnit,      // empty/permission centred message
+    val stripeH: Dp,            // coloured event stripe height
+    val iconImage: Dp,          // header action icon glyph
+    val iconBox: Dp,            // header action touch target
+    val rowVPad: Dp,            // event row vertical padding
+    val dayHeaderTopPad: Dp,    // space above a day header
+) {
+    /**
+     * Resolves the stripe height against the user's system font scale.
+     *
+     * The stripe is a [Dp] but the two text lines it sits beside are `sp`, so
+     * they scale with the accessibility font setting and the stripe does not —
+     * at "Largest" the text outgrows the stripe and it visibly under-runs the row
+     * it is supposed to mark. Multiplying by the same factor keeps them locked,
+     * and at the default scale of 1.0 reproduces the tier's value exactly.
+     */
+    fun scaledForFont(fontScale: Float): AgendaMetrics =
+        if (fontScale == 1f) this else copy(stripeH = stripeH * fontScale)
+}
+
+/*
+ * Type sizes are anchored to the Material 3 type scale (see the `material-3`
+ * skill's typography reference) rather than invented: 16sp is Title Medium, 14sp
+ * Body Medium / Title Small, 12sp Body Small, 16sp Body Large, 22sp Title Large.
+ *
+ * Two documented deviations:
+ *
+ *  ‡ COMPACT's 13sp day header is off-scale. It is held there deliberately —
+ *    COMPACT reproduces the widget's original constants verbatim so a
+ *    default-sized widget looks exactly as it did (#51), and snapping it to
+ *    Title Small (14sp) would break that promise for a 1sp gain.
+ *
+ *  † Above Title Medium the M3 scale jumps 16 → 22 → 24 with nothing in between,
+ *    which is far too coarse for four widget tiers. Where a role would force a
+ *    ≥1.4x step between adjacent tiers we hold an interpolated value instead and
+ *    mark it. The endpoints stay on real roles.
+ */
+
+private val COMPACT_METRICS = AgendaMetrics(
+    title = 16.sp,       // M3 Title Medium
+    dayHeader = 13.sp,   // ‡ off-scale, holds the #51 baseline
+    eventTitle = 14.sp,  // M3 Body Medium
+    eventTime = 12.sp,   // M3 Body Small
+    placeholder = 14.sp, // M3 Body Medium
+    message = 14.sp,     // M3 Body Medium
+    stripeH = 36.dp,
+    iconImage = 22.dp,
+    iconBox = 40.dp,
+    rowVPad = 4.dp,
+    dayHeaderTopPad = 10.dp,
+)
+
+private val REGULAR_METRICS = AgendaMetrics(
+    title = 18.sp,       // †
+    dayHeader = 14.sp,   // M3 Title Small
+    eventTitle = 16.sp,  // M3 Body Large
+    eventTime = 14.sp,   // M3 Body Medium
+    placeholder = 16.sp, // M3 Body Large
+    message = 16.sp,     // M3 Body Large
+    stripeH = 40.dp,
+    iconImage = 24.dp,
+    iconBox = 44.dp,
+    rowVPad = 5.dp,
+    dayHeaderTopPad = 11.dp,
+)
+
+private val LARGE_METRICS = AgendaMetrics(
+    title = 20.sp,       // †
+    dayHeader = 16.sp,   // M3 Title Medium
+    eventTitle = 18.sp,  // †
+    eventTime = 14.sp,   // M3 Body Medium — the secondary line steps more slowly
+    placeholder = 18.sp, // †                on purpose, so the title keeps its
+    message = 18.sp,     // †                lead and the hierarchy survives.
+    stripeH = 46.dp,
+    iconImage = 26.dp,
+    iconBox = 48.dp,
+    rowVPad = 6.dp,
+    dayHeaderTopPad = 12.dp,
+)
+
+private val XLARGE_METRICS = AgendaMetrics(
+    title = 22.sp,       // M3 Title Large
+    dayHeader = 18.sp,   // †
+    eventTitle = 20.sp,  // †
+    eventTime = 16.sp,   // M3 Body Large
+    placeholder = 20.sp, // †
+    message = 20.sp,     // †
+    stripeH = 52.dp,
+    iconImage = 28.dp,
+    iconBox = 52.dp,
+    rowVPad = 8.dp,
+    dayHeaderTopPad = 14.dp,
+)
+
+/** Indexed by [WidgetScale.ordinal] so lookup allocates nothing per recomposition. */
+private val AGENDA_METRICS = listOf(
+    COMPACT_METRICS,
+    REGULAR_METRICS,
+    LARGE_METRICS,
+    XLARGE_METRICS,
+)
+
+internal fun metricsFor(scale: WidgetScale): AgendaMetrics = AGENDA_METRICS[scale.ordinal]

app/src/main/java/de/jeanlucmakiola/calendula/widget/agenda/AgendaWidget.kt

@@ -5,7 +5,6 @@ import android.content.res.Configuration
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.unit.dp
-import androidx.compose.ui.unit.sp
 import androidx.datastore.preferences.core.booleanPreferencesKey
 import androidx.datastore.preferences.core.stringPreferencesKey
 import androidx.glance.ColorFilter
@@ -14,9 +13,11 @@ import androidx.glance.GlanceModifier
 import androidx.glance.GlanceTheme
 import androidx.glance.Image
 import androidx.glance.ImageProvider
+import androidx.glance.LocalSize
 import androidx.glance.action.ActionParameters
 import androidx.glance.action.clickable
 import androidx.glance.appwidget.GlanceAppWidget
+import androidx.glance.appwidget.SizeMode
 import androidx.glance.appwidget.action.ActionCallback
 import androidx.glance.appwidget.action.actionRunCallback
 import androidx.glance.appwidget.action.actionStartActivity
@@ -61,6 +62,7 @@ import de.jeanlucmakiola.floret.locale.localizedDateFormatter
 import de.jeanlucmakiola.calendula.ui.common.eventFill
 import de.jeanlucmakiola.calendula.widget.AgendaWidgetData
 import de.jeanlucmakiola.calendula.widget.CalendulaGlanceTheme
+import de.jeanlucmakiola.calendula.widget.scaleFor
 import de.jeanlucmakiola.calendula.widget.loadAgendaWidgetData
 import de.jeanlucmakiola.calendula.widget.systemZone
 import de.jeanlucmakiola.calendula.widget.today
@@ -107,6 +109,19 @@ class AgendaWidget : GlanceAppWidget() {
 
     override val stateDefinition = PreferencesGlanceStateDefinition
 
+    // Exact so the composition sees the widget's live size and can scale type/rows
+    // from it ([scaleFor]/[metricsFor]); at the default size that resolves to
+    // COMPACT, i.e. the layout is unchanged (#51). MonthWidget already does the
+    // same.
+    //
+    // Note Exact still asks Glance for one RemoteViews per host size (typically
+    // portrait + landscape) where the old SizeMode.Single produced exactly one —
+    // so the serialized payload roughly doubles. That is why the row list below is
+    // capped: an uncapped agenda (the range goes up to AgendaRange.MAX_CUSTOM_DAYS
+    // = 365) could otherwise push the RemoteViews past the binder transaction
+    // limit and the host would just show "Problem loading widget".
+    override val sizeMode = SizeMode.Exact
+
     override suspend fun provideGlance(context: Context, id: GlanceId) {
         val data = context.loadAgendaWidgetData()
         val dark = (context.resources.configuration.uiMode and
@@ -126,6 +141,15 @@ class RefreshAgendaAction : ActionCallback {
     }
 }
 
+/**
+ * Upper bound on rows handed to the [LazyColumn], so the serialized RemoteViews
+ * stays well inside the binder transaction limit regardless of range and calendar
+ * size (see the [SizeMode.Exact] note above). Far more than fits on screen — a
+ * user scrolling a home-screen widget past a hundred rows is not a case worth
+ * risking a failed update for.
+ */
+private const val MAX_AGENDA_ROWS = 100
+
 /** Flat row model so the [LazyColumn] can mix day headers and events. */
 private sealed interface AgendaRow {
     data class Header(val date: LocalDate, val today: LocalDate) : AgendaRow
@@ -136,16 +160,22 @@ private sealed interface AgendaRow {
 
 @Composable
 private fun AgendaWidgetBody(data: AgendaWidgetData, dark: Boolean) {
+    // Type and row metrics scale with the widget's live size (SizeMode.Exact); a
+    // short/compact widget resolves to COMPACT, leaving the layout unchanged (#51).
+    // The stripe is then re-resolved against the system font scale so it tracks the
+    // sp-sized text beside it instead of drifting at large accessibility settings.
+    val fontScale = androidx.glance.LocalContext.current.resources.configuration.fontScale
+    val metrics = metricsFor(scaleFor(LocalSize.current)).scaledForFont(fontScale)
     Column(
         modifier = GlanceModifier
             .fillMaxSize()
             .background(GlanceTheme.colors.surface)
             .padding(horizontal = 8.dp, vertical = 6.dp),
     ) {
-        AgendaHeader()
+        AgendaHeader(metrics)
         Spacer(GlanceModifier.height(4.dp))
         when (data) {
-            AgendaWidgetData.NeedsPermission -> WidgetMessage(R.string.widget_needs_permission)
+            AgendaWidgetData.NeedsPermission -> WidgetMessage(R.string.widget_needs_permission, metrics)
             is AgendaWidgetData.Ready -> {
                 // Range read reactively from per-instance Glance state (falls back
                 // to the saved pref for a freshly placed widget), then the wide
@@ -179,7 +209,7 @@ private fun AgendaWidgetBody(data: AgendaWidgetData, dark: Boolean) {
                     enabled = showToday,
                 )
                 if (visibleDays.isEmpty()) {
-                    WidgetMessage(R.string.agenda_empty_title)
+                    WidgetMessage(R.string.agenda_empty_title, metrics)
                 } else {
                     val rows = buildList {
                         visibleDays.forEach { day ->
@@ -191,11 +221,15 @@ private fun AgendaWidgetBody(data: AgendaWidgetData, dark: Boolean) {
                             }
                         }
                     }
+                        // Bound the payload, then drop a day header the cut left
+                        // stranded with nothing under it.
+                        .take(MAX_AGENDA_ROWS)
+                        .dropLastWhile { it is AgendaRow.Header }
                     LazyColumn(modifier = GlanceModifier.fillMaxSize()) {
                         items(rows.size) { index ->
                             when (val row = rows[index]) {
-                                is AgendaRow.Header -> DayHeaderRow(row.date, row.today)
-                                is AgendaRow.Placeholder -> PlaceholderRow(row.date)
+                                is AgendaRow.Header -> DayHeaderRow(row.date, row.today, metrics)
+                                is AgendaRow.Placeholder -> PlaceholderRow(row.date, metrics)
                                 is AgendaRow.Event -> EventRow(
                                     event = row.event,
                                     day = row.date,
@@ -204,6 +238,7 @@ private fun AgendaWidgetBody(data: AgendaWidgetData, dark: Boolean) {
                                     is24Hour = data.is24Hour,
                                     dimmed = pastDisplay == PastEventDisplay.DIM &&
                                         row.event.hasEnded(data.now),
+                                    metrics = metrics,
                                 )
                             }
                         }
@@ -215,7 +250,7 @@ private fun AgendaWidgetBody(data: AgendaWidgetData, dark: Boolean) {
 }
 
 @Composable
-private fun AgendaHeader() {
+private fun AgendaHeader(metrics: AgendaMetrics) {
     val context = androidx.glance.LocalContext.current
     Row(
         modifier = GlanceModifier.fillMaxWidth().padding(horizontal = 4.dp),
@@ -227,7 +262,7 @@ private fun AgendaHeader() {
             text = context.getString(R.string.widget_agenda_title),
             style = TextStyle(
                 color = GlanceTheme.colors.primary,
-                fontSize = 16.sp,
+                fontSize = metrics.title,
                 fontWeight = FontWeight.Medium,
             ),
             modifier = GlanceModifier
@@ -240,6 +275,7 @@ private fun AgendaHeader() {
             resId = R.drawable.ic_widget_refresh,
             contentDescription = context.getString(R.string.widget_refresh),
             onClick = GlanceModifier.clickable(actionRunCallback<RefreshAgendaAction>()),
+            metrics = metrics,
         )
         IconButton(
             resId = R.drawable.ic_widget_add,
@@ -249,39 +285,50 @@ private fun AgendaHeader() {
                     MainActivity.openCreateIntent(context, today(systemZone())),
                 ),
             ),
+            metrics = metrics,
         )
     }
 }
 
 @Composable
-private fun IconButton(resId: Int, contentDescription: String, onClick: GlanceModifier) {
+private fun IconButton(
+    resId: Int,
+    contentDescription: String,
+    onClick: GlanceModifier,
+    metrics: AgendaMetrics,
+) {
     Box(
-        modifier = GlanceModifier.size(40.dp).then(onClick),
+        modifier = GlanceModifier.size(metrics.iconBox).then(onClick),
         contentAlignment = Alignment.Center,
     ) {
         Image(
             provider = ImageProvider(resId),
             contentDescription = contentDescription,
             colorFilter = ColorFilter.tint(GlanceTheme.colors.onSurfaceVariant),
-            modifier = GlanceModifier.size(22.dp),
+            modifier = GlanceModifier.size(metrics.iconImage),
         )
     }
 }
 
 @Composable
-private fun DayHeaderRow(date: LocalDate, today: LocalDate) {
+private fun DayHeaderRow(date: LocalDate, today: LocalDate, metrics: AgendaMetrics) {
     val context = androidx.glance.LocalContext.current
     Text(
         text = agendaDayLabel(context, date, today),
         style = TextStyle(
             color = if (date == today) GlanceTheme.colors.primary
             else GlanceTheme.colors.onSurfaceVariant,
-            fontSize = 13.sp,
+            fontSize = metrics.dayHeader,
             fontWeight = FontWeight.Medium,
         ),
         modifier = GlanceModifier
             .fillMaxWidth()
-            .padding(start = 8.dp, end = 8.dp, top = 10.dp, bottom = 4.dp)
+            .padding(
+                start = 8.dp,
+                end = 8.dp,
+                top = metrics.dayHeaderTopPad,
+                bottom = metrics.rowVPad,
+            )
             .clickable(
                 actionStartActivity(
                     MainActivity.openDateIntent(context, date, CalendarView.Agenda),
@@ -296,14 +343,19 @@ private fun DayHeaderRow(date: LocalDate, today: LocalDate) {
  * plain too (a stripe + text, not cards), so a card here would look out of place.
  */
 @Composable
-private fun PlaceholderRow(date: LocalDate) {
+private fun PlaceholderRow(date: LocalDate, metrics: AgendaMetrics) {
     val context = androidx.glance.LocalContext.current
     Text(
         text = context.getString(R.string.agenda_no_more_today),
-        style = TextStyle(color = GlanceTheme.colors.onSurfaceVariant, fontSize = 14.sp),
+        style = TextStyle(color = GlanceTheme.colors.onSurfaceVariant, fontSize = metrics.placeholder),
         modifier = GlanceModifier
             .fillMaxWidth()
-            .padding(start = 19.dp, end = 8.dp, top = 2.dp, bottom = 6.dp)
+            .padding(
+                start = TEXT_INDENT,
+                end = 8.dp,
+                top = 2.dp,
+                bottom = metrics.rowVPad + 2.dp,
+            )
             .clickable(
                 actionStartActivity(
                     MainActivity.openDateIntent(context, date, CalendarView.Agenda),
@@ -320,6 +372,7 @@ private fun EventRow(
     soften: Boolean,
     is24Hour: Boolean,
     dimmed: Boolean,
+    metrics: AgendaMetrics,
 ) {
     val context = androidx.glance.LocalContext.current
     val title = event.title.ifBlank { context.getString(R.string.event_untitled) }
@@ -332,7 +385,7 @@ private fun EventRow(
     Row(
         modifier = GlanceModifier
             .fillMaxWidth()
-            .padding(horizontal = 4.dp, vertical = 4.dp)
+            .padding(horizontal = ROW_H_PAD, vertical = metrics.rowVPad)
             .clickable(
                 actionStartActivity(
                     MainActivity.openEventIntent(
@@ -348,29 +401,29 @@ private fun EventRow(
     ) {
         Box(
             modifier = GlanceModifier
-                .width(5.dp)
-                .height(36.dp)
+                .width(STRIPE_WIDTH)
+                .height(metrics.stripeH)
                 .cornerRadius(3.dp)
                 .background(stripeColor),
         ) {}
-        Spacer(GlanceModifier.width(10.dp))
+        Spacer(GlanceModifier.width(STRIPE_GAP))
         Column(modifier = GlanceModifier.defaultWeight()) {
             Text(
                 text = title,
                 maxLines = 1,
-                style = TextStyle(color = titleColor, fontSize = 14.sp),
+                style = TextStyle(color = titleColor, fontSize = metrics.eventTitle),
             )
             Text(
                 text = eventTimeSummary(context, event, day, is24Hour),
                 maxLines = 1,
-                style = TextStyle(color = GlanceTheme.colors.onSurfaceVariant, fontSize = 12.sp),
+                style = TextStyle(color = GlanceTheme.colors.onSurfaceVariant, fontSize = metrics.eventTime),
             )
         }
     }
 }
 
 @Composable
-private fun WidgetMessage(resId: Int) {
+private fun WidgetMessage(resId: Int, metrics: AgendaMetrics) {
     val context = androidx.glance.LocalContext.current
     Box(
         modifier = GlanceModifier.fillMaxSize().padding(16.dp),
@@ -378,7 +431,7 @@ private fun WidgetMessage(resId: Int) {
     ) {
         Text(
             text = context.getString(resId),
-            style = TextStyle(color = GlanceTheme.colors.onSurfaceVariant, fontSize = 14.sp),
+            style = TextStyle(color = GlanceTheme.colors.onSurfaceVariant, fontSize = metrics.message),
         )
     }
 }

app/src/main/res/values/strings.xml

@@ -1,6 +1,10 @@
 <resources>
     <string name="app_name">Calendula</string>
     <string name="app_tagline">A modern calendar.</string>
+    <!-- Alternative launcher label offered by the "App name" setting (issue #44).
+         translatable="false": this string becomes a launcher component's label, so
+         it must never be changed by an unreviewed community translation. -->
+    <string name="app_name_calendar_alias" translatable="false">Calendar</string>
 
     <!-- Loading / Failure / Success generic strings (used across screens) -->
     <string name="state_loading">Loading…</string>
@@ -106,7 +110,6 @@
     <string name="event_edit_timezone_recent">Recent</string>
     <string name="event_edit_timezone_all">All time zones</string>
     <string name="event_edit_timezone_none">No time zone matches “%1$s”</string>
-    <string name="event_edit_timezone_clear">Use device zone</string>
     <!-- Shown under the time fields when the event is pinned to another zone:
          the same event expressed where the user actually is. %1$s is a time
          range, e.g. "2:00 PM – 3:00 PM". -->
@@ -332,6 +335,8 @@
     <string name="settings_week_numbers_summary">Show calendar-week numbers in month view</string>
     <string name="settings_today_toolbar">Today button in toolbar</string>
     <string name="settings_today_toolbar_summary">Show a jump-to-today button in the toolbar instead of a floating button</string>
+    <string name="settings_app_name">App name</string>
+    <string name="settings_app_name_summary">Show Calendula as “Calendar” in your launcher. Only the launcher name changes; the icon may move to a new spot after switching.</string>
     <string name="settings_time_format">Time format</string>
     <string name="settings_time_format_auto">Automatic</string>
     <string name="settings_time_format_12h">12-hour (2:00 PM)</string>

app/src/test/java/de/jeanlucmakiola/calendula/data/appname/LauncherNameManagerTest.kt

@@ -0,0 +1,51 @@
+package de.jeanlucmakiola.calendula.data.appname
+
+import android.content.pm.PackageManager
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+/**
+ * Pure decision logic behind the app-name toggle (issue #44). The framework seam
+ * ([LauncherNameManager.set]/[current], which call `PackageManager`) is covered
+ * on-device; these tests pin the read interpretation and the write ordering.
+ */
+class LauncherNameManagerTest {
+
+    @Test
+    fun `enabled calendar alias reads as CALENDAR`() {
+        assertThat(launcherNameFor(PackageManager.COMPONENT_ENABLED_STATE_ENABLED))
+            .isEqualTo(LauncherName.CALENDAR)
+    }
+
+    @Test
+    fun `default and disabled calendar alias read as CALENDULA`() {
+        assertThat(launcherNameFor(PackageManager.COMPONENT_ENABLED_STATE_DEFAULT))
+            .isEqualTo(LauncherName.CALENDULA)
+        assertThat(launcherNameFor(PackageManager.COMPONENT_ENABLED_STATE_DISABLED))
+            .isEqualTo(LauncherName.CALENDULA)
+    }
+
+    @Test
+    fun `write plan enables the target alias before disabling the other`() {
+        val toCalendar = aliasWritePlan(LauncherName.CALENDAR)
+        assertThat(toCalendar).containsExactly(
+            AliasStateChange(LauncherAlias.CALENDAR, enabled = true),
+            AliasStateChange(LauncherAlias.DEFAULT, enabled = false),
+        ).inOrder()
+
+        val toCalendula = aliasWritePlan(LauncherName.CALENDULA)
+        assertThat(toCalendula).containsExactly(
+            AliasStateChange(LauncherAlias.DEFAULT, enabled = true),
+            AliasStateChange(LauncherAlias.CALENDAR, enabled = false),
+        ).inOrder()
+    }
+
+    @Test
+    fun `write plan never disables both aliases in the same step`() {
+        // The first step is always an enable, so the launcher can never observe a
+        // zero-entry transient regardless of switch direction.
+        for (target in LauncherName.entries) {
+            assertThat(aliasWritePlan(target).first().enabled).isTrue()
+        }
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/EventWriteMapperTest.kt

@@ -123,8 +123,18 @@ class EventWriteMapperTest {
 
     private val seriesStart = 1_700_000_000_000L
 
-    private fun update(original: EventForm, updated: EventForm): Map<String, Any?> =
-        buildEventUpdateValues(original, updated, seriesStart, berlin)
+    private fun update(
+        original: EventForm,
+        updated: EventForm,
+        series: Long = seriesStart,
+    ): Map<String, Any?> = buildEventUpdateValues(original, updated, series, berlin)
+
+    /** The instant [local] names in [zoneId], as the provider would store it. */
+    private fun instantAt(local: String, zoneId: String): Long =
+        java.time.LocalDateTime.parse(local)
+            .atZone(java.time.ZoneId.of(zoneId))
+            .toInstant()
+            .toEpochMilli()
 
     @Test
     fun `pristine form produces no values`() {
@@ -219,6 +229,77 @@ class EventWriteMapperTest {
         assertThat(values[CalendarContract.Events.DURATION]).isEqualTo("P5400S")
     }
 
+    @Test
+    fun `pinning a recurring event to another zone keeps the series wall clock`() {
+        // The regression this guards: the series DTSTART used to move by a
+        // millisecond delta measured at the *edited occurrence*. Here the series
+        // anchor sits in January (Berlin CET, +1) and the edited occurrence in
+        // July (Berlin CEST, +2), so the July delta is an hour off for January —
+        // the whole series would have drifted to 10:00 Tokyo.
+        val series = instantAt("2026-01-07T09:00", "Europe/Berlin")
+        val original = form(
+            start = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(9, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(10, 0)),
+        ).copy(rrule = "FREQ=WEEKLY")
+
+        val values = update(original, original.copy(timezone = "Asia/Tokyo"), series)
+
+        assertThat(values[CalendarContract.Events.EVENT_TIMEZONE]).isEqualTo("Asia/Tokyo")
+        // The anchor still reads 09:00 — now 09:00 in Tokyo, not 10:00.
+        assertThat(values[CalendarContract.Events.DTSTART])
+            .isEqualTo(instantAt("2026-01-07T09:00", "Asia/Tokyo"))
+    }
+
+    @Test
+    fun `a time edit moves the series anchor in wall clock across a DST boundary`() {
+        // Anchor in winter, edited occurrence in summer: pushing the occurrence
+        // one hour later must leave the anchor at 10:00 winter time, not at an
+        // instant that re-reads as 11:00 once the offset differs.
+        val series = instantAt("2026-01-07T09:00", "Europe/Berlin")
+        val original = form(
+            start = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(9, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(10, 0)),
+        ).copy(rrule = "FREQ=WEEKLY")
+        val moved = original.copy(
+            start = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(10, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(11, 0)),
+        )
+
+        assertThat(update(original, moved, series)[CalendarContract.Events.DTSTART])
+            .isEqualTo(instantAt("2026-01-07T10:00", "Europe/Berlin"))
+    }
+
+    @Test
+    fun `moving a recurring occurrence to another day shifts the anchor by whole days`() {
+        val series = instantAt("2026-01-07T09:00", "Europe/Berlin")
+        val original = form(
+            start = LocalDateTime(LocalDate(2026, 1, 7), LocalTime(9, 0)),
+            end = LocalDateTime(LocalDate(2026, 1, 7), LocalTime(10, 0)),
+        ).copy(rrule = "FREQ=WEEKLY")
+        val moved = original.copy(
+            start = LocalDateTime(LocalDate(2026, 1, 9), LocalTime(14, 30)),
+            end = LocalDateTime(LocalDate(2026, 1, 9), LocalTime(15, 30)),
+        )
+
+        assertThat(update(original, moved, series)[CalendarContract.Events.DTSTART])
+            .isEqualTo(instantAt("2026-01-09T14:30", "Europe/Berlin"))
+    }
+
+    @Test
+    fun `switching a recurring event to all-day anchors the series on a UTC midnight`() {
+        val series = instantAt("2026-01-07T09:00", "Europe/Berlin")
+        val original = form(
+            start = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(9, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(10, 0)),
+        ).copy(rrule = "FREQ=WEEKLY")
+
+        val values = update(original, original.copy(isAllDay = true), series)
+
+        assertThat(values[CalendarContract.Events.EVENT_TIMEZONE]).isEqualTo("UTC")
+        val dtStart = values[CalendarContract.Events.DTSTART] as Long
+        assertThat(dtStart % (24L * 60 * 60 * 1000)).isEqualTo(0L)
+    }
+
     @Test
     fun `adding a recurrence keeps the times and writes rule plus duration`() {
         val original = form()

app/src/test/java/de/jeanlucmakiola/calendula/widget/WidgetScaleTest.kt

@@ -0,0 +1,89 @@
+package de.jeanlucmakiola.calendula.widget
+
+import androidx.compose.ui.unit.DpSize
+import androidx.compose.ui.unit.dp
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class WidgetScaleTest {
+
+    @Test
+    fun `the on-device calibration points map to their tiers`() {
+        // The two sizes measured on-device: the compact widget stays COMPACT (the
+        // baseline, unchanged), the full-width one steps up to LARGE — not XLARGE,
+        // which read as too big on a phone (#51).
+        assertThat(scaleFor(DpSize(222.dp, 270.dp))).isEqualTo(WidgetScale.COMPACT)
+        assertThat(scaleFor(DpSize(378.dp, 672.dp))).isEqualTo(WidgetScale.LARGE)
+    }
+
+    @Test
+    fun `a full-width widget at ordinary height still scales up`() {
+        // The regression the height cap used to cause: widening the widget without
+        // also making it unusually tall is *the* resize #51 reports, and it must
+        // reach the tier its width earned. Three cells tall is about 270dp.
+        assertThat(scaleFor(DpSize(378.dp, 270.dp))).isEqualTo(WidgetScale.LARGE)
+        assertThat(scaleFor(DpSize(300.dp, 270.dp))).isEqualTo(WidgetScale.REGULAR)
+        assertThat(scaleFor(DpSize(460.dp, 300.dp))).isEqualTo(WidgetScale.XLARGE)
+    }
+
+    @Test
+    fun `width buckets into the four tiers`() {
+        // Tall enough that the height cap never binds, isolating the width rule.
+        val h = 500.dp
+        assertThat(scaleFor(DpSize(180.dp, h))).isEqualTo(WidgetScale.COMPACT)
+        assertThat(scaleFor(DpSize(259.dp, h))).isEqualTo(WidgetScale.COMPACT)
+        assertThat(scaleFor(DpSize(260.dp, h))).isEqualTo(WidgetScale.REGULAR)
+        assertThat(scaleFor(DpSize(329.dp, h))).isEqualTo(WidgetScale.REGULAR)
+        assertThat(scaleFor(DpSize(330.dp, h))).isEqualTo(WidgetScale.LARGE)
+        assertThat(scaleFor(DpSize(419.dp, h))).isEqualTo(WidgetScale.LARGE)
+        assertThat(scaleFor(DpSize(420.dp, h))).isEqualTo(WidgetScale.XLARGE)
+        assertThat(scaleFor(DpSize(900.dp, h))).isEqualTo(WidgetScale.XLARGE)
+    }
+
+    @Test
+    fun `extra height never raises the tier`() {
+        // Height decides how many rows are visible, not how big they are: a tall,
+        // narrow widget wants more events, not bigger text.
+        assertThat(scaleFor(DpSize(222.dp, 200.dp))).isEqualTo(WidgetScale.COMPACT)
+        assertThat(scaleFor(DpSize(222.dp, 900.dp))).isEqualTo(WidgetScale.COMPACT)
+        assertThat(scaleFor(DpSize(300.dp, 900.dp))).isEqualTo(WidgetScale.REGULAR)
+    }
+
+    @Test
+    fun `only a genuinely squashed widget is stepped back down`() {
+        // Same (wide) width, shrinking height. The cap exists to stop oversized type
+        // surviving in a one- or two-row sliver — it must not fire at normal heights.
+        // Heights are gross; the cap works on height minus 60dp of chrome, so the
+        // LARGE floor is 190dp (130dp usable) and the REGULAR floor 130dp (70dp).
+        val wide = 378.dp
+        assertThat(scaleFor(DpSize(wide, 400.dp))).isEqualTo(WidgetScale.LARGE)
+        assertThat(scaleFor(DpSize(wide, 260.dp))).isEqualTo(WidgetScale.LARGE)
+        assertThat(scaleFor(DpSize(wide, 190.dp))).isEqualTo(WidgetScale.LARGE)
+        assertThat(scaleFor(DpSize(wide, 189.dp))).isEqualTo(WidgetScale.REGULAR)
+        assertThat(scaleFor(DpSize(wide, 130.dp))).isEqualTo(WidgetScale.REGULAR)
+        assertThat(scaleFor(DpSize(wide, 129.dp))).isEqualTo(WidgetScale.COMPACT)
+        // The provider's declared floor (minResizeWidth/Height = 110dp) is COMPACT.
+        assertThat(scaleFor(DpSize(110.dp, 110.dp))).isEqualTo(WidgetScale.COMPACT)
+    }
+
+    @Test
+    fun `the tier is monotonic in both axes`() {
+        // Growing a widget must never make its type smaller. Sweeps the whole
+        // plausible range rather than spot-checking, so a future threshold edit
+        // can't accidentally invert a step.
+        val widths = (110..900 step 7).map { it.dp }
+        val heights = (110..900 step 7).map { it.dp }
+        widths.forEach { w ->
+            heights.zipWithNext { shorter, taller ->
+                assertThat(scaleFor(DpSize(w, taller)))
+                    .isAtLeast(scaleFor(DpSize(w, shorter)))
+            }
+        }
+        heights.forEach { h ->
+            widths.zipWithNext { narrower, wider ->
+                assertThat(scaleFor(DpSize(wider, h)))
+                    .isAtLeast(scaleFor(DpSize(narrower, h)))
+            }
+        }
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/widget/agenda/AgendaScaleTest.kt

@@ -0,0 +1,121 @@
+package de.jeanlucmakiola.calendula.widget.agenda
+
+import androidx.compose.ui.unit.DpSize
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.widget.WidgetScale
+import de.jeanlucmakiola.calendula.widget.scaleFor
+import org.junit.jupiter.api.Test
+
+class AgendaScaleTest {
+
+    // --- the "default size is unchanged" regression guard ---------------------
+
+    @Test
+    fun `every default placement width stays COMPACT`() {
+        // Ties the guarantee to the provider XML's declared 3-cell default rather
+        // than to one measured launcher: the whole band a default placement can
+        // land in must bucket to COMPACT, or a freshly placed widget silently
+        // changes appearance (#51). See AGENDA_DEFAULT_WIDTH_BAND.
+        val band = AGENDA_DEFAULT_WIDTH_BAND
+        var w = band.start
+        while (w <= band.endInclusive) {
+            assertThat(scaleFor(DpSize(w, 270.dp))).isEqualTo(WidgetScale.COMPACT)
+            w += 1.dp
+        }
+    }
+
+    @Test
+    fun `COMPACT metrics equal the widget's original constants`() {
+        // If this fails, a default-sized agenda widget no longer looks as it did.
+        val m = metricsFor(WidgetScale.COMPACT)
+        assertThat(m.title).isEqualTo(16.sp)
+        assertThat(m.dayHeader).isEqualTo(13.sp)
+        assertThat(m.eventTitle).isEqualTo(14.sp)
+        assertThat(m.eventTime).isEqualTo(12.sp)
+        assertThat(m.placeholder).isEqualTo(14.sp)
+        assertThat(m.message).isEqualTo(14.sp)
+        assertThat(m.stripeH).isEqualTo(36.dp)
+        assertThat(m.iconImage).isEqualTo(22.dp)
+        assertThat(m.iconBox).isEqualTo(40.dp)
+        assertThat(m.rowVPad).isEqualTo(4.dp)
+        assertThat(m.dayHeaderTopPad).isEqualTo(10.dp)
+    }
+
+    @Test
+    fun `the derived text indent matches the original hardcoded inset`() {
+        // TEXT_INDENT replaced a hardcoded 19dp; it must still resolve to 19dp or
+        // day headers and the placeholder line stop aligning with event titles.
+        assertThat(TEXT_INDENT).isEqualTo(19.dp)
+        assertThat(TEXT_INDENT).isEqualTo(ROW_H_PAD + STRIPE_WIDTH + STRIPE_GAP)
+    }
+
+    // --- the ramp ------------------------------------------------------------
+
+    @Test
+    fun `sizes are non-decreasing across the tiers`() {
+        val tiers = WidgetScale.entries.map(::metricsFor)
+
+        tiers.zipWithNext { small, big ->
+            assertThat(big.title.value).isAtLeast(small.title.value)
+            assertThat(big.dayHeader.value).isAtLeast(small.dayHeader.value)
+            assertThat(big.eventTitle.value).isAtLeast(small.eventTitle.value)
+            assertThat(big.eventTime.value).isAtLeast(small.eventTime.value)
+            assertThat(big.placeholder.value).isAtLeast(small.placeholder.value)
+            assertThat(big.message.value).isAtLeast(small.message.value)
+            assertThat(big.stripeH.value).isAtLeast(small.stripeH.value)
+            assertThat(big.iconImage.value).isAtLeast(small.iconImage.value)
+            assertThat(big.iconBox.value).isAtLeast(small.iconBox.value)
+            assertThat(big.rowVPad.value).isAtLeast(small.rowVPad.value)
+            assertThat(big.dayHeaderTopPad.value).isAtLeast(small.dayHeaderTopPad.value)
+        }
+    }
+
+    @Test
+    fun `the event title keeps its lead over the time line`() {
+        // The secondary line steps more slowly on purpose; if it ever caught up the
+        // row would lose its hierarchy.
+        WidgetScale.entries.map(::metricsFor).forEach { m ->
+            assertThat(m.eventTitle.value).isGreaterThan(m.eventTime.value)
+        }
+    }
+
+    @Test
+    fun `no tier grows type more than half again over the baseline`() {
+        // Guards against a future edit turning "more readable" into "absurd".
+        val base = metricsFor(WidgetScale.COMPACT)
+        val top = metricsFor(WidgetScale.XLARGE)
+        assertThat(top.title.value / base.title.value).isLessThan(1.5f)
+        assertThat(top.eventTitle.value / base.eventTitle.value).isLessThan(1.5f)
+    }
+
+    // --- font scale ----------------------------------------------------------
+
+    @Test
+    fun `the stripe tracks the system font scale`() {
+        // The stripe is Dp, the text beside it is sp: without this the two diverge
+        // at large accessibility font settings and the stripe under-runs the row.
+        val m = metricsFor(WidgetScale.COMPACT)
+        assertThat(m.scaledForFont(1f).stripeH).isEqualTo(36.dp)
+        assertThat(m.scaledForFont(1.3f).stripeH.value).isWithin(0.01f).of(46.8f)
+        assertThat(m.scaledForFont(0.85f).stripeH.value).isWithin(0.01f).of(30.6f)
+    }
+
+    @Test
+    fun `scaling for the default font scale changes nothing`() {
+        val m = metricsFor(WidgetScale.LARGE)
+        assertThat(m.scaledForFont(1f)).isSameInstanceAs(m)
+    }
+
+    @Test
+    fun `font scaling leaves the sp sizes alone`() {
+        // Glance already applies the font scale to sp; scaling them here too would
+        // double-count it.
+        val m = metricsFor(WidgetScale.REGULAR)
+        val scaled = m.scaledForFont(1.3f)
+        assertThat(scaled.title).isEqualTo(m.title)
+        assertThat(scaled.eventTitle).isEqualTo(m.eventTitle)
+        assertThat(scaled.rowVPad).isEqualTo(m.rowVPad)
+    }
+}