Rebuild the event colour system on Oklch (#21, #36)

Colours were shaped in HSV, whose "value" is not perceived brightness:
at one pinned value the hues spread across relative luminance 0.10 to
0.45, straddling the black/white ink crossover at 0.179. So the ink was
decided by hue — red and purple took white, orange and blue took black —
and the fills nearest the crossover were the mid colours that contrast
badly with either ink.

Shape them in Oklch instead, where lightness matches what the eye calls
brightness, and split the two jobs one colour was doing: a container
sits behind text and must contrast with its ink, an accent is a mark on
a surface and must contrast with the surface. Nine call sites that were
painting marks now ask for the accent.

Colours go to whichever pole they already sit nearer rather than all
being forced deep — a dark orange is brown and a dark yellow is olive,
so the warm, naturally light hues keep their character and take dark ink
while the rest go deep and take white. Either way they land clear of the
middle, which was the fault. White ink is now 5.6-6.3:1 on every deep
hue and dark ink 11:1 on the light ones, against 2.7-8.2:1 before.

Picker curation now calls the same eventTone the picker paints with,
instead of a copy of the shaping kept in step by hand, and drops its CIE
Lab helper for Oklab distance. Renames the setting to "harmonise", since
it no longer softens anything.

app/src/main/java/de/jeanlucmakiola/calendula/MainActivity.kt

@@ -29,6 +29,7 @@ import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.buildInsertEventForm
 import de.jeanlucmakiola.calendula.ui.RootScreen
 import de.jeanlucmakiola.calendula.ui.common.LocalShowHourLines
+import de.jeanlucmakiola.calendula.ui.common.LocalTimelineScale
 import de.jeanlucmakiola.calendula.ui.common.LocalSoftenColors
 import de.jeanlucmakiola.calendula.ui.common.LocalUse24HourFormat
 import de.jeanlucmakiola.calendula.ui.WidgetNavRequest
@@ -141,6 +142,7 @@ class MainActivity : AppCompatActivity() {
                     CompositionLocalProvider(
                         LocalUse24HourFormat provides use24Hour,
                         LocalShowHourLines provides settings.showHourLines,
+                        LocalTimelineScale provides settings.timelineScale,
                         LocalSoftenColors provides settings.softenColors,
                     ) {
                         RootScreen(

app/src/main/java/de/jeanlucmakiola/calendula/data/prefs/SettingsPrefs.kt

@@ -21,6 +21,7 @@ import de.jeanlucmakiola.calendula.ui.agenda.storageValue
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
 import de.jeanlucmakiola.calendula.ui.common.IMPLEMENTED_VIEWS
 import de.jeanlucmakiola.calendula.ui.common.QuickSwitchConfig
+import de.jeanlucmakiola.calendula.ui.common.TimelineScale
 import de.jeanlucmakiola.calendula.ui.month.MonthViewStyle
 import de.jeanlucmakiola.calendula.ui.theme.FONT_SYSTEM_TOKEN
 import de.jeanlucmakiola.calendula.widget.WidgetSize
@@ -270,6 +271,18 @@ class SettingsPrefs @Inject constructor(
         store.edit { it[MONTH_VIEW_STYLE_KEY] = style.name }
     }
 
+    /**
+     * How tall an hour is drawn in the week and day timelines (#56). Defaults to
+     * [TimelineScale.Regular] — the historical 56dp scale.
+     */
+    val timelineScale: Flow<TimelineScale> = store.data.map { prefs ->
+        prefs[TIMELINE_SCALE_KEY].toEnum(TimelineScale.Regular)
+    }
+
+    suspend fun setTimelineScale(scale: TimelineScale) {
+        store.edit { it[TIMELINE_SCALE_KEY] = scale.name }
+    }
+
     /**
      * Where the jump-to-today control lives (issue #60). Default OFF — the
      * historical layout, where it's an extended FAB that fades in above the "+"
@@ -808,6 +821,7 @@ class SettingsPrefs @Inject constructor(
         internal val DIM_COMPLETED_EVENTS_KEY = booleanPreferencesKey("dim_completed_events")
         internal val SHOW_WEEK_NUMBERS_KEY = booleanPreferencesKey("show_week_numbers")
         internal val MONTH_VIEW_STYLE_KEY = stringPreferencesKey("month_view_style")
+        internal val TIMELINE_SCALE_KEY = stringPreferencesKey("timeline_scale")
         internal val TODAY_BUTTON_IN_TOOLBAR_KEY = booleanPreferencesKey("today_button_in_toolbar")
         internal val DEFAULT_VIEW_KEY = stringPreferencesKey("default_view")
         internal val QUICK_SWITCH_VIEWS_KEY = stringPreferencesKey("quick_switch_views")

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

@@ -1,12 +1,8 @@
 package de.jeanlucmakiola.calendula.domain
 
-import kotlin.math.abs
-import kotlin.math.atan2
-import kotlin.math.cbrt
-import kotlin.math.hypot
-import kotlin.math.pow
-import kotlin.math.roundToInt
-import kotlin.math.sqrt
+import de.jeanlucmakiola.calendula.domain.color.Oklch
+import de.jeanlucmakiola.calendula.domain.color.eventTone
+import de.jeanlucmakiola.calendula.domain.color.oklchOf
 
 /**
  * Curates an account's published event palette for the colour picker.
@@ -18,24 +14,25 @@ import kotlin.math.sqrt
  * (#22).
  *
  * Crucially, curation runs against the colour the picker actually *paints*, not
- * the raw provider value. The picker softens every swatch through [pastelArgb]:
- * it pins lightness to a constant and caps saturation, so the raw palette's
- * lightness axis is invisible on screen. Two raw colours that look different —
- * a navy and a mid blue — paint as one swatch, and every neutral (black, the
- * grays, white) paints as the same pale tint. Judging distinctness in raw
- * space, as before, left near-identical painted swatches and stranded the
- * neutrals as a run of look-alike "pinks" at the end of the grid.
+ * the raw provider value — and it gets that colour from the same [eventTone]
+ * the picker calls, rather than from a copy of its shaping kept in step by hand.
+ * Because a harmonised container pins lightness, the raw palette's lightness
+ * axis is invisible on screen: two raw colours that look different — a navy and
+ * a mid blue — paint as one swatch, and every neutral (black, the grays, white)
+ * paints as the same grey. Judging distinctness in raw space, as before, left
+ * near-identical painted swatches and stranded the neutrals as a run of
+ * look-alike tints at the end of the grid.
  *
  * Three steps, all in painted space:
  *  1. Collapse swatches that paint identically to one (alphabetically-first key
  *     wins, deterministically) — this folds aliases, dark/light shades of a
  *     hue, and all the neutrals together.
- *  2. Oversized palettes (> [CURATION_TRIGGER_SIZE]) drop the washed-out
- *     neutral-origin tints (painted chroma < [PASTEL_CHROMA_FLOOR]) and are
- *     then thinned to visually distinct colours: most vivid first, a colour is
- *     kept only when at least [MIN_DELTA_E] (CIE76, painted Lab) from every
- *     colour already kept. Small palettes are already curated by their adapter
- *     and pass through whole.
+ *  2. Oversized palettes (> [CURATION_TRIGGER_SIZE]) drop the neutral-origin
+ *     swatches — with lightness pinned, a grey source paints as plain grey, so
+ *     "has no hue left" is simply zero chroma — and are then thinned to visually
+ *     distinct colours: most vivid first, a colour is kept only when at least
+ *     [MIN_DISTANCE] away in Oklab from every colour already kept. Small
+ *     palettes are already curated by their adapter and pass through whole.
  *  3. The survivors are ordered like a rainbow — continuously by painted hue —
  *     with the wheel cut at its single widest empty gap so the one unavoidable
  *     seam lands in dead space and no hue family is torn across both ends.
@@ -45,12 +42,12 @@ import kotlin.math.sqrt
  */
 fun List<EventColorOption>.curatedForPicker(): List<EventColorOption> {
     val painted = sortedBy { it.key }
-        .distinctBy { pastelArgb(it.argb) }
-        .map { it to Lab.of(pastelArgb(it.argb)) }
+        .distinctBy { paintedArgb(it.argb) }
+        .map { it to oklchOf(paintedArgb(it.argb)) }
     val kept = if (painted.size <= CURATION_TRIGGER_SIZE) {
         painted
     } else {
-        thin(painted.filter { (_, lab) -> lab.chroma >= PASTEL_CHROMA_FLOOR })
+        thin(painted.filter { (_, painted) -> painted.chroma > 0f })
     }
     return orderAroundWheel(kept).map { (option, _) -> option }
 }
@@ -61,17 +58,17 @@ fun List<EventColorOption>.curatedForPicker(): List<EventColorOption> {
  * instead of mid-family. Saturation breaks ties, vivid first.
  */
 private fun orderAroundWheel(
-    swatches: List<Pair<EventColorOption, Lab>>,
-): List<Pair<EventColorOption, Lab>> {
+    swatches: List<Pair<EventColorOption, Oklch>>,
+): List<Pair<EventColorOption, Oklch>> {
     if (swatches.size < 2) return swatches
     val byHue = swatches.sortedWith(
-        compareBy({ (_, lab) -> lab.hue }, { (_, lab) -> -lab.chroma }),
+        compareBy({ (_, painted) -> painted.hue }, { (_, painted) -> -painted.chroma }),
     )
     // Split the wheel after the largest empty arc between neighbouring hues;
     // the default is the wrap gap (last hue back round to the first), i.e. the
     // familiar 0→360 order, and we only rotate away from it for a wider void.
     var cutAfter = byHue.lastIndex
-    var widestGap = 360.0 - byHue.last().second.hue + byHue.first().second.hue
+    var widestGap = 360f - byHue.last().second.hue + byHue.first().second.hue
     for (i in 0 until byHue.lastIndex) {
         val gap = byHue[i + 1].second.hue - byHue[i].second.hue
         if (gap > widestGap) {
@@ -84,102 +81,32 @@ private fun orderAroundWheel(
 
 /** Greedy max-distance filter: vivid colours stake out clusters first. */
 private fun thin(
-    swatches: List<Pair<EventColorOption, Lab>>,
-): List<Pair<EventColorOption, Lab>> {
+    swatches: List<Pair<EventColorOption, Oklch>>,
+): List<Pair<EventColorOption, Oklch>> {
     val byVividness = swatches
-        .sortedWith(compareByDescending<Pair<EventColorOption, Lab>> { it.second.chroma }.thenBy { it.first.key })
-    val kept = mutableListOf<Pair<EventColorOption, Lab>>()
+        .sortedWith(
+            compareByDescending<Pair<EventColorOption, Oklch>> { it.second.chroma }
+                .thenBy { it.first.key },
+        )
+    val kept = mutableListOf<Pair<EventColorOption, Oklch>>()
     for (candidate in byVividness) {
-        if (kept.none { it.second.deltaE(candidate.second) < MIN_DELTA_E }) kept += candidate
+        if (kept.none { it.second.distanceTo(candidate.second) < MIN_DISTANCE }) kept += candidate
     }
     return kept
 }
 
-/**
- * The softening the colour picker paints over every swatch: keep the hue, scale
- * and clamp saturation into a gentle band, and pin value to a constant so
- * nothing screams and everything reads on the surface. Value is fixed here so
- * curation is theme-independent — only hue and saturation distinguish painted
- * swatches.
- *
- * This is a self-contained mirror of floret-kit's `pastelize` hue/saturation
- * shaping (`de.jeanlucmakiola.floret.components.pastelize`), with value pinned
- * rather than theme-picked. Curation must reason about the colour the picker
- * paints, so the two shapings have to agree: if floret's saturation band or
- * curve changes, update this in step.
- */
-fun pastelArgb(rawArgb: Int): Int {
-    val r = ((rawArgb shr 16) and 0xFF) / 255f
-    val g = ((rawArgb shr 8) and 0xFF) / 255f
-    val b = (rawArgb and 0xFF) / 255f
-    val max = maxOf(r, g, b)
-    val min = minOf(r, g, b)
-    val delta = max - min
-    val hue = when {
-        delta == 0f -> 0f
-        max == r -> 60f * (((g - b) / delta) % 6f)
-        max == g -> 60f * (((b - r) / delta) + 2f)
-        else -> 60f * (((r - g) / delta) + 4f)
-    }.let { if (it < 0f) it + 360f else it }
-    val sat = (if (max == 0f) 0f else delta / max) * 0.6f
-    val s = sat.coerceIn(0.25f, 0.65f)
-    val v = PASTEL_VALUE
-    val c = v * s
-    val x = c * (1f - abs((hue / 60f) % 2f - 1f))
-    val m = v - c
-    val (rr, gg, bb) = when {
-        hue < 60f -> Triple(c, x, 0f)
-        hue < 120f -> Triple(x, c, 0f)
-        hue < 180f -> Triple(0f, c, x)
-        hue < 240f -> Triple(0f, x, c)
-        hue < 300f -> Triple(x, 0f, c)
-        else -> Triple(c, 0f, x)
-    }
-    fun channel(value: Float) = ((value + m) * 255f).roundToInt().coerceIn(0, 255)
-    return (0xFF shl 24) or (channel(rr) shl 16) or (channel(gg) shl 8) or channel(bb)
-}
-
-/** Reference lightness for curation; the picker paints at this on dark surfaces. */
-private const val PASTEL_VALUE = 0.82f
+/** The colour the picker paints for [argb]; the light theme stands in as the
+ *  reference, since a harmonised container differs only in lightness by theme
+ *  and curation compares hue and chroma. */
+private fun paintedArgb(argb: Int): Int =
+    eventTone(argb, dark = false, harmonise = true).container
 
 /** Palettes at most this big skip the thinning (Google's ~26 pass through). */
 private const val CURATION_TRIGGER_SIZE = 36
 
-/** Minimum CIE76 ΔE between surviving painted swatches. */
-private const val MIN_DELTA_E = 13.0
-
 /**
- * Painted-chroma floor for oversized palettes: below this a swatch is a washed-
- * out tint — the neutrals and near-whites the saturation clamp muddies — so it
- * is dropped rather than shown as pale filler.
+ * Minimum Oklab distance between surviving painted swatches. Painted colours all
+ * share one lightness, so this is really a hue/chroma separation — far enough
+ * apart that two swatches never read as the same colour in the grid.
  */
-private const val PASTEL_CHROMA_FLOOR = 22.0
-
-/** CIE Lab (D65) — the space where Euclidean distance ≈ perceived difference. */
-private class Lab(val l: Double, val a: Double, val b: Double) {
-    val chroma: Double get() = hypot(a, b)
-
-    /** Hue angle in degrees, 0–360, around the Lab a-b plane. */
-    val hue: Double get() = (Math.toDegrees(atan2(b, a)) + 360.0) % 360.0
-
-    fun deltaE(other: Lab): Double =
-        sqrt((l - other.l).pow(2) + (a - other.a).pow(2) + (b - other.b).pow(2))
-
-    companion object {
-        fun of(argb: Int): Lab {
-            fun linear(shift: Int): Double {
-                val c = ((argb shr shift) and 0xFF) / 255.0
-                return if (c <= 0.04045) c / 12.92 else ((c + 0.055) / 1.055).pow(2.4)
-            }
-            val r = linear(16)
-            val g = linear(8)
-            val b = linear(0)
-            val x = (0.4124 * r + 0.3576 * g + 0.1805 * b) / 0.95047
-            val y = 0.2126 * r + 0.7152 * g + 0.0722 * b
-            val z = (0.0193 * r + 0.1192 * g + 0.9505 * b) / 1.08883
-            fun f(t: Double) = if (t > 0.008856) cbrt(t) else 7.787 * t + 16.0 / 116.0
-            val fy = f(y)
-            return Lab(116 * fy - 16, 500 * (f(x) - fy), 200 * (fy - f(z)))
-        }
-    }
-}
+private const val MIN_DISTANCE = 0.025f

app/src/main/java/de/jeanlucmakiola/calendula/domain/color/EventTone.kt

@@ -0,0 +1,124 @@
+package de.jeanlucmakiola.calendula.domain.color
+
+/**
+ * The colours one calendar's identity resolves to in one theme.
+ *
+ * The app paints a calendar's colour in two structurally different places, and
+ * they want opposite things:
+ *
+ *  - a **[container]** sits behind text (week and day blocks, month bars, widget
+ *    rows, picker swatches), so it has to contrast with its own ink;
+ *  - an **[accent]** is a mark on an ordinary app surface (day dots, agenda and
+ *    search stripes, calendar icon tints, the detail header), so it has to
+ *    contrast with the *surface* instead.
+ *
+ * Painting both from one colour is what made this hard to get right: deep enough
+ * to carry white text is too dark to see as a dot on a dark surface, and light
+ * enough to show up there is too pale to carry white text. Splitting them lets
+ * each be pinned to the lightness its job needs, while hue and chroma — the parts
+ * that actually say *which calendar this is* — stay shared, so the two roles
+ * still read as the same colour.
+ */
+data class EventTone(
+    val container: Int,
+    val onContainer: Int,
+    val accent: Int,
+)
+
+/**
+ * Resolve [rawArgb] for the current theme.
+ *
+ * With [harmonise] on, hue and chroma are kept and lightness is re-pinned per
+ * role, which is what makes the ink predictable: every container lands at the
+ * same perceptual lightness, so one ink colour serves every hue at ≥ 6:1. With
+ * it off the provider's colour is painted verbatim — the sync source's own look,
+ * as DAVx5/CalDAV users expect — and the ink is then chosen per colour, since
+ * nothing constrains what the provider sends.
+ */
+fun eventTone(rawArgb: Int, dark: Boolean, harmonise: Boolean): EventTone {
+    val opaque = rawArgb or 0xFF000000.toInt()
+    val raw = oklchOf(opaque)
+    if (!harmonise) {
+        return EventTone(
+            container = opaque,
+            onContainer = inkFor(raw.lightness),
+            accent = opaque,
+        )
+    }
+    // A near-grey source has no hue worth keeping, so it stays grey rather than
+    // being pushed to an arbitrary one; everything else is held inside a band
+    // that keeps calendars apart without going neon.
+    val chroma = if (raw.chroma < GREY_CHROMA) 0f else raw.chroma.coerceIn(MIN_CHROMA, MAX_CHROMA)
+    // Two poles rather than one. Forcing every hue deep is what turned the warm,
+    // naturally light ones muddy — a dark orange is brown and a dark yellow is
+    // olive, which is a fact about those hues, not a tuning miss. So a colour is
+    // sent to whichever pole it already sits nearer: most land deep and carry
+    // white ink, while genuinely light sources (yellows, creams, pale tints)
+    // stay light and carry dark ink, keeping the character that made them
+    // recognisable. Either way the colour is pulled clear of the middle, where
+    // neither ink reads well — which was the original fault.
+    val staysLight = raw.lightness >= LIGHT_POLE_THRESHOLD
+    val containerLightness = when {
+        staysLight && dark -> LIGHT_CONTAINER_LIGHTNESS_DARK
+        staysLight -> LIGHT_CONTAINER_LIGHTNESS_LIGHT
+        dark -> CONTAINER_LIGHTNESS_DARK
+        else -> CONTAINER_LIGHTNESS_LIGHT
+    }
+    // The accent takes no pole: it is a mark on the app's surface, so it has to
+    // contrast with that surface whichever way its container went.
+    val accentLightness = if (dark) ACCENT_LIGHTNESS_DARK else ACCENT_LIGHTNESS_LIGHT
+    return EventTone(
+        container = Oklch(containerLightness, chroma, raw.hue).toArgb(),
+        onContainer = inkFor(containerLightness),
+        accent = Oklch(accentLightness, chroma, raw.hue).toArgb(),
+    )
+}
+
+/**
+ * White or black ink for a background of the given perceptual [lightness].
+ *
+ * Derived rather than hardcoded so it stays right for raw provider colours,
+ * where lightness is whatever the sync source sent. For harmonised containers it
+ * is constant by construction — that is the point of pinning the lightness.
+ */
+fun inkFor(lightness: Float): Int =
+    if (lightness < INK_FLIP_LIGHTNESS) 0xFFFFFFFF.toInt() else 0xFF000000.toInt()
+
+/**
+ * Lightness at which white ink overtakes black. Sits above the midpoint because
+ * lightness is perceptual: a colour has to be distinctly light before black wins.
+ */
+const val INK_FLIP_LIGHTNESS = 0.62f
+
+/**
+ * Raw lightness at or above which a colour keeps its light character instead of
+ * being pushed deep. Set high enough that oranges and warm reds still go deep —
+ * a burnt orange reads as orange, where a dark yellow does not read as yellow —
+ * so only the genuinely pale sources take the light pole.
+ */
+const val LIGHT_POLE_THRESHOLD = 0.72f
+
+/** Container lightness: deep enough that white ink clears 5.5:1 on every hue. */
+const val CONTAINER_LIGHTNESS_LIGHT = 0.45f
+
+/** Same in dark mode, a shade lighter so a block separates from the surface. */
+const val CONTAINER_LIGHTNESS_DARK = 0.48f
+
+/** Light-pole container: pale enough that dark ink clears 11:1 on every hue. */
+const val LIGHT_CONTAINER_LIGHTNESS_LIGHT = 0.88f
+
+/** Same in dark mode, held down a little so a pale block doesn't glare. */
+const val LIGHT_CONTAINER_LIGHTNESS_DARK = 0.84f
+
+/** Accent lightness: dark enough to read as a mark on a pale surface. */
+const val ACCENT_LIGHTNESS_LIGHT = 0.55f
+
+/** Same against a dark surface, where the mark has to be the light one. */
+const val ACCENT_LIGHTNESS_DARK = 0.78f
+
+/** Below this chroma a colour counts as grey and keeps no hue. */
+const val GREY_CHROMA = 0.02f
+
+/** Chroma band for harmonised colours: distinct, but never electric. */
+const val MIN_CHROMA = 0.07f
+const val MAX_CHROMA = 0.16f

app/src/main/java/de/jeanlucmakiola/calendula/domain/color/Oklch.kt

@@ -0,0 +1,119 @@
+package de.jeanlucmakiola.calendula.domain.color
+
+import kotlin.math.atan2
+import kotlin.math.cbrt
+import kotlin.math.cos
+import kotlin.math.hypot
+import kotlin.math.pow
+import kotlin.math.sin
+import kotlin.math.sqrt
+
+/**
+ * A colour in Oklch — Oklab's cylindrical form: perceptual [lightness], [chroma]
+ * (colourfulness) and [hue] in degrees.
+ *
+ * The point of using it over HSV is that its lightness axis matches what the eye
+ * calls brightness. HSV's "value" does not: at a single pinned value the hues
+ * spread across relative luminance 0.10 (indigo) to 0.45 (yellow), which is why
+ * pinning value produced fills that needed different ink per hue. Pin Oklch
+ * lightness instead and every hue lands at the same apparent brightness, so one
+ * ink serves all of them.
+ *
+ * [lightness] runs 0 (black) to 1 (white); [chroma] is 0 (grey) to about 0.32 at
+ * the sRGB limit.
+ */
+data class Oklch(val lightness: Float, val chroma: Float, val hue: Float) {
+
+    /**
+     * Perceptual distance to [other] — plain Euclidean in Oklab, which is what
+     * Oklab is built for (unlike CIE Lab, where CIE76 is known to misjudge
+     * saturated blues).
+     */
+    fun distanceTo(other: Oklch): Float {
+        val (a1, b1) = chroma * cosDeg(hue) to chroma * sinDeg(hue)
+        val (a2, b2) = other.chroma * cosDeg(other.hue) to other.chroma * sinDeg(other.hue)
+        val dl = (lightness - other.lightness).toDouble()
+        return sqrt(dl * dl + (a1 - a2).pow(2) + (b1 - b2).pow(2)).toFloat()
+    }
+}
+
+/** Read [argb]'s opaque colour as Oklch. */
+fun oklchOf(argb: Int): Oklch {
+    val r = toLinear(((argb shr 16) and 0xFF) / 255.0)
+    val g = toLinear(((argb shr 8) and 0xFF) / 255.0)
+    val b = toLinear((argb and 0xFF) / 255.0)
+
+    val l = cbrt(0.4122214708 * r + 0.5363325363 * g + 0.0514459929 * b)
+    val m = cbrt(0.2119034982 * r + 0.6806995451 * g + 0.1073969566 * b)
+    val s = cbrt(0.0883024619 * r + 0.2817188376 * g + 0.6299787005 * b)
+
+    val lightness = 0.2104542553 * l + 0.7936177850 * m - 0.0040720468 * s
+    val aAxis = 1.9779984951 * l - 2.4285922050 * m + 0.4505937099 * s
+    val bAxis = 0.0259040371 * l + 0.7827717662 * m - 0.8086757660 * s
+
+    val hue = (Math.toDegrees(atan2(bAxis, aAxis)) + 360.0) % 360.0
+    return Oklch(lightness.toFloat(), hypot(aAxis, bAxis).toFloat(), hue.toFloat())
+}
+
+/**
+ * The opaque sRGB colour for this Oklch, gamut-mapped: most of the Oklch cylinder
+ * falls outside sRGB, so a colour that does not fit keeps its lightness and hue
+ * and gives up chroma until it does. Holding lightness is what matters here —
+ * it's the axis the contrast guarantees rest on.
+ */
+fun Oklch.toArgb(): Int {
+    val fitted = if (inSrgb(lightness, chroma, hue)) {
+        chroma
+    } else {
+        var low = 0f
+        var high = chroma
+        repeat(GAMUT_STEPS) {
+            val mid = (low + high) / 2f
+            if (inSrgb(lightness, mid, hue)) low = mid else high = mid
+        }
+        low
+    }
+    val (r, g, b) = linearSrgbOf(lightness, fitted, hue)
+    return 0xFF shl 24 or
+        (channel(r) shl 16) or
+        (channel(g) shl 8) or
+        channel(b)
+}
+
+private fun linearSrgbOf(lightness: Float, chroma: Float, hue: Float): Triple<Double, Double, Double> {
+    val a = chroma * cosDeg(hue)
+    val b = chroma * sinDeg(hue)
+    val l = (lightness + 0.3963377774 * a + 0.2158037573 * b).pow(3)
+    val m = (lightness - 0.1055613458 * a - 0.0638541728 * b).pow(3)
+    val s = (lightness - 0.0894841775 * a - 1.2914855480 * b).pow(3)
+    return Triple(
+        4.0767416621 * l - 3.3077115913 * m + 0.2309699292 * s,
+        -1.2684380046 * l + 2.6097574011 * m - 0.3413193965 * s,
+        -0.0041960863 * l - 0.7034186147 * m + 1.7076147010 * s,
+    )
+}
+
+private fun inSrgb(lightness: Float, chroma: Float, hue: Float): Boolean {
+    val (r, g, b) = linearSrgbOf(lightness, chroma, hue)
+    return r in -GAMUT_EPSILON..(1.0 + GAMUT_EPSILON) &&
+        g in -GAMUT_EPSILON..(1.0 + GAMUT_EPSILON) &&
+        b in -GAMUT_EPSILON..(1.0 + GAMUT_EPSILON)
+}
+
+private fun channel(linear: Double): Int =
+    (toSrgb(linear.coerceIn(0.0, 1.0)) * 255.0).toInt().coerceIn(0, 255)
+
+private fun toLinear(c: Double): Double =
+    if (c <= 0.04045) c / 12.92 else ((c + 0.055) / 1.055).pow(2.4)
+
+private fun toSrgb(c: Double): Double =
+    if (c <= 0.0031308) 12.92 * c else 1.055 * c.pow(1.0 / 2.4) - 0.055
+
+private fun cosDeg(deg: Float) = cos(Math.toRadians(deg.toDouble()))
+private fun sinDeg(deg: Float) = sin(Math.toRadians(deg.toDouble()))
+
+/** Bisection steps when pulling an out-of-gamut colour back into sRGB. */
+private const val GAMUT_STEPS = 24
+
+/** Slack for the gamut test, so rounding at the boundary doesn't reject a fit. */
+private const val GAMUT_EPSILON = 1e-4

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

@@ -31,6 +31,7 @@ import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.ui.common.EventDimAlpha
 import de.jeanlucmakiola.calendula.ui.common.LocalSoftenColors
 import de.jeanlucmakiola.calendula.ui.common.LocalUse24HourFormat
+import de.jeanlucmakiola.calendula.ui.common.eventAccent
 import de.jeanlucmakiola.calendula.ui.common.eventFill
 import de.jeanlucmakiola.calendula.ui.common.formatTimeOfDay
 import de.jeanlucmakiola.floret.components.GroupedRow
@@ -137,7 +138,7 @@ internal fun AgendaEventRow(
                 modifier = Modifier
                     .size(width = 6.dp, height = 36.dp)
                     .clip(RoundedCornerShape(3.dp))
-                    .background(eventFill(event.color, dark, soften)),
+                    .background(eventAccent(event.color, dark, soften)),
             )
         },
         onClick = onClick,

app/src/main/java/de/jeanlucmakiola/calendula/ui/calendars/CalendarsScreen.kt

@@ -88,6 +88,7 @@ import de.jeanlucmakiola.calendula.ui.common.CalendarColorChip
 import de.jeanlucmakiola.calendula.ui.common.accountGroupTitle
 import de.jeanlucmakiola.calendula.ui.common.groupByAccount
 import de.jeanlucmakiola.calendula.ui.common.LocalSoftenColors
+import de.jeanlucmakiola.calendula.ui.common.eventAccent
 import de.jeanlucmakiola.calendula.ui.common.eventFill
 import de.jeanlucmakiola.calendula.ui.common.LeadingAvatar
 import de.jeanlucmakiola.calendula.ui.common.SourceLogo
@@ -442,7 +443,7 @@ private fun CalendarEditor(
                     )
                 }
             }
-            EditorCard(icon = Icons.Default.CalendarMonth, iconTint = eventFill(color, dark, soften)) {
+            EditorCard(icon = Icons.Default.CalendarMonth, iconTint = eventAccent(color, dark, soften)) {
                 InlineTextField(
                     value = name,
                     onValueChange = { name = it },

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

@@ -35,7 +35,7 @@ fun CalendarColorChip(color: Int, modifier: Modifier = Modifier) {
         Icon(
             Icons.Filled.CalendarMonth,
             contentDescription = null,
-            tint = eventFill(color, dark, soften),
+            tint = eventAccent(color, dark, soften),
             modifier = Modifier.size(22.dp),
         )
     }

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

@@ -2,45 +2,53 @@ package de.jeanlucmakiola.calendula.ui.common
 
 import androidx.compose.runtime.staticCompositionLocalOf
 import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.graphics.luminance
-import de.jeanlucmakiola.floret.components.pastelize
+import de.jeanlucmakiola.calendula.domain.color.eventTone
+import de.jeanlucmakiola.calendula.domain.color.inkFor
+import de.jeanlucmakiola.calendula.domain.color.oklchOf
 
 /**
- * Whether calendar/event colours are softened toward theme-fitting pastels
- * before display (issue #36). Provided app-wide from the "soften colours"
- * setting; the default `true` keeps the historical look. When off, the raw
- * provider colour is painted verbatim — matching the sync source (DAVx5/CalDAV)
- * and other calendar apps. Widgets live outside this composition and read the
- * preference directly, then pass the flag to [eventFill] / [eventInk].
+ * Whether calendar/event colours are harmonised — hue kept, lightness re-pinned
+ * per role — before display (issue #36). Provided app-wide from the setting; the
+ * default `true` is the app's own look. When off, the raw provider colour is
+ * painted verbatim, matching the sync source (DAVx5/CalDAV) and other calendar
+ * apps. Widgets live outside this composition and read the preference directly,
+ * then pass the flag through.
  */
 val LocalSoftenColors = staticCompositionLocalOf { true }
 
 /**
- * Display fill for an event chip/bar or a calendar tint: the [pastelize]d colour
- * when [soften] is on, else the raw provider ARGB verbatim (forced opaque, since
- * pastelize also returns an opaque colour).
+ * Fill for a surface that carries text on it — a week/day block, a month bar, a
+ * widget row, a picker swatch. Pair it with [eventInk].
  */
 fun eventFill(rawArgb: Int, dark: Boolean, soften: Boolean): Color =
-    if (soften) pastelize(rawArgb, dark) else Color(rawArgb or 0xFF000000.toInt())
+    Color(eventTone(rawArgb, dark, soften).container)
 
 /**
- * Contrast ink (title text / glyph) for a filled chip painted with [eventFill]:
- * white on a dark fill, near-black on a light one (issue #21). Applies to both
- * softened and raw fills — a saturated hue (deep blue, purple, red) is
- * perceptually dark even after softening pins its HSV value, so black text on it
- * reads poorly. The choice is objective, not a tuned threshold: white wins only
- * when it out-contrasts black against the fill, which (by the WCAG contrast
- * ratio) is at relative luminance ≈ 0.18 — so mid and light colours keep
- * near-black text. [alpha] carries the caller's soft emphasis.
+ * Colour for a mark on an ordinary app surface — a day dot, an agenda or search
+ * stripe, a calendar icon tint, the detail header. Same identity as [eventFill],
+ * pinned to contrast with the surface instead of with ink.
  */
-fun eventInk(fill: Color, alpha: Float = 0.8f): Color {
-    val useWhite = fill.luminance() < INK_LUMINANCE_CROSSOVER
-    return (if (useWhite) Color.White else Color.Black).copy(alpha = alpha)
-}
+fun eventAccent(rawArgb: Int, dark: Boolean, soften: Boolean): Color =
+    Color(eventTone(rawArgb, dark, soften).accent)
 
 /**
- * Relative-luminance crossover where white text starts to out-contrast black.
- * Solving `contrast(white, L) = contrast(black, L)` on the WCAG ratio gives
- * `L = sqrt(1.05 * 0.05) - 0.05 ≈ 0.179`.
+ * Ink for text drawn on an [eventFill]. [alpha] carries the caller's emphasis.
+ *
+ * Takes the fill rather than the raw colour so it stays correct for the raw
+ * (un-harmonised) path too, where the provider decides the lightness.
  */
-private const val INK_LUMINANCE_CROSSOVER = 0.179f
+fun eventInk(fill: Color, alpha: Float = 0.8f): Color =
+    Color(inkFor(oklchOf(fill.toArgbInt()).lightness)).copy(alpha = alpha)
+
+/**
+ * Ink alpha for a block's secondary line (the time under the title). Held above
+ * a fainter value because harmonised containers are deep: the small time text
+ * needs to stay clear of the 4.5:1 WCAG asks of body text.
+ */
+const val SECONDARY_INK_ALPHA = 0.8f
+
+private fun Color.toArgbInt(): Int =
+    (0xFF shl 24) or
+        ((red * 255f).toInt().coerceIn(0, 255) shl 16) or
+        ((green * 255f).toInt().coerceIn(0, 255) shl 8) or
+        (blue * 255f).toInt().coerceIn(0, 255)

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

@@ -0,0 +1,94 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.annotation.StringRes
+import androidx.compose.runtime.staticCompositionLocalOf
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.calendula.R
+
+/**
+ * How tall one hour is drawn in the week and day timelines (#56).
+ *
+ * One shared setting for both views: they are the same grid at different widths,
+ * and a scale that only applied to one of them would read as a bug.
+ *
+ * [FitDay] is the answer to the actual complaint behind the issue — on a tall
+ * phone the default scale shows about half a day, so a whole week can hide
+ * appointments below the fold. It derives the hour height from the timeline's
+ * own viewport instead of a fixed value.
+ */
+enum class TimelineScale {
+    /** Whole day in one screen: the hour height follows the viewport. */
+    FitDay,
+
+    /** Denser than the default, still a fixed height. */
+    Compact,
+
+    /** The historical 56dp scale. */
+    Regular,
+
+    /** Roomier blocks, more scrolling. */
+    Comfortable,
+}
+
+/** The scale the timelines draw at, from the `timelineScale` preference. */
+val LocalTimelineScale = staticCompositionLocalOf { TimelineScale.Regular }
+
+/**
+ * Hour height for this scale. [viewportHeight] is the visible height of the
+ * scrolling timeline and is only consulted by [TimelineScale.FitDay].
+ *
+ * The fit-day result is clamped: below [FIT_DAY_MIN] the 24 gutter labels stop
+ * being legible, and above [FIT_DAY_MAX] a short landscape day would stretch its
+ * blocks absurdly. On a screen too short for the whole day the clamp wins and
+ * the timeline still scrolls a little — honest, rather than unreadable.
+ */
+fun TimelineScale.hourHeight(viewportHeight: Dp): Dp = when (this) {
+    TimelineScale.FitDay -> (viewportHeight / 24f).coerceIn(FIT_DAY_MIN, FIT_DAY_MAX)
+    TimelineScale.Compact -> 40.dp
+    TimelineScale.Regular -> 56.dp
+    TimelineScale.Comfortable -> 80.dp
+}
+
+/**
+ * Shortest an event block may render, as a fraction of an hour. Blocks keep a
+ * floor so a 15-minute event stays tappable, but the floor scales with the hour
+ * height — a fixed 24dp would swallow half an hour once zoomed out and make
+ * short events overlap their neighbours.
+ */
+const val MIN_EVENT_FRACTION = 26f / 60f
+
+/**
+ * Narrowest an event block may be and still wrap its title over several lines.
+ *
+ * Wrapping is driven by the block's height, so a tall block on a lane-split
+ * column would otherwise stack two or three characters per line — "Da/ily",
+ * "Fa/rmer/s…" — which reads worse than one ellipsised line. A full week column
+ * clears this on any phone; a split one never does, while the day view's much
+ * wider columns keep wrapping even several lanes deep.
+ */
+val MIN_TITLE_WRAP_WIDTH = 36.dp
+
+/** Smallest hour height [TimelineScale.FitDay] will resolve to. */
+val FIT_DAY_MIN = 24.dp
+
+/** Largest hour height [TimelineScale.FitDay] will resolve to. */
+val FIT_DAY_MAX = 96.dp
+
+@get:StringRes
+val TimelineScale.labelRes: Int
+    get() = when (this) {
+        TimelineScale.FitDay -> R.string.timeline_scale_fit_day
+        TimelineScale.Compact -> R.string.timeline_scale_compact
+        TimelineScale.Regular -> R.string.timeline_scale_regular
+        TimelineScale.Comfortable -> R.string.timeline_scale_comfortable
+    }
+
+@get:StringRes
+val TimelineScale.descriptionRes: Int
+    get() = when (this) {
+        TimelineScale.FitDay -> R.string.timeline_scale_fit_day_summary
+        TimelineScale.Compact -> R.string.timeline_scale_compact_summary
+        TimelineScale.Regular -> R.string.timeline_scale_regular_summary
+        TimelineScale.Comfortable -> R.string.timeline_scale_comfortable_summary
+    }

app/src/main/java/de/jeanlucmakiola/calendula/ui/day/DayScreen.kt

@@ -87,6 +87,10 @@ import de.jeanlucmakiola.calendula.ui.common.rememberCalendarSlideSpec
 import de.jeanlucmakiola.floret.locale.currentLocale
 import de.jeanlucmakiola.calendula.ui.common.LocalUse24HourFormat
 import de.jeanlucmakiola.calendula.ui.common.LocalShowHourLines
+import de.jeanlucmakiola.calendula.ui.common.LocalTimelineScale
+import de.jeanlucmakiola.calendula.ui.common.MIN_EVENT_FRACTION
+import de.jeanlucmakiola.calendula.ui.common.SECONDARY_INK_ALPHA
+import de.jeanlucmakiola.calendula.ui.common.hourHeight
 import de.jeanlucmakiola.calendula.ui.common.formatHourLabel
 import de.jeanlucmakiola.calendula.ui.common.formatMinuteOfDay
 import de.jeanlucmakiola.calendula.ui.common.hourSeparatorLines
@@ -100,13 +104,11 @@ import kotlin.time.Clock
 import java.util.Locale
 import kotlin.math.roundToInt
 
-private val HOUR_HEIGHT = 56.dp
 private val GUTTER_WIDTH = 48.dp
 /** Start inset for the gutter's hour labels so they centre on the top bar's
  *  hamburger: with a 48dp gutter, 8dp lands the centre at 28dp (the app bar's
  *  4dp inset + 24dp half icon button), matching the week view. */
 private val GUTTER_CONTENT_START_INSET = 8.dp
-private val MIN_EVENT_HEIGHT = 24.dp
 private val ALL_DAY_ROW_HEIGHT = 24.dp
 private val ALL_DAY_VERTICAL_PADDING = 6.dp
 
@@ -264,7 +266,6 @@ private fun DayContent(
     onCreateAt: (LocalDate, Int) -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    val density = LocalDensity.current
     val slideSpec = rememberCalendarSlideSpec()
     val fadeSpec = rememberCalendarFadeSpec()
     val reduceMotion = rememberReduceMotion()
@@ -275,11 +276,9 @@ private fun DayContent(
     val scrollState = rememberScrollState()
     LaunchedEffect(Unit) {
         snapshotFlow { scrollState.maxValue }.first { it > 0 }
-        val maxV = scrollState.maxValue
-        val target = with(density) {
-            (HOUR_HEIGHT.toPx() * 12 - (HOUR_HEIGHT.toPx() * 24 - maxV) / 2f).roundToInt()
-        }.coerceIn(0, maxV)
-        scrollState.scrollTo(target)
+        // Half the scroll range *is* noon: the content spans a full 24 hours, so
+        // centring the range centres midday at whatever hour height is in force.
+        scrollState.scrollTo(scrollState.maxValue / 2)
     }
 
     // Single, hoisted all-day strip height — shared by the outgoing and incoming
@@ -485,12 +484,17 @@ private fun Timeline(
     onEventClick: (EventInstance) -> Unit,
     onCreateAt: (LocalDate, Int) -> Unit,
 ) {
-    val totalHeight = HOUR_HEIGHT * 24
     val dark = isSystemInDarkTheme()
     val use24Hour = LocalUse24HourFormat.current
     val locale = currentLocale()
+    val scale = LocalTimelineScale.current
 
-    Box(modifier = Modifier.fillMaxSize()) {
+    // BoxWithConstraints rather than Box: the fit-the-whole-day scale needs the
+    // timeline's own viewport height, which is only known here — below the top
+    // bar, date header and all-day strip.
+    BoxWithConstraints(modifier = Modifier.fillMaxSize()) {
+        val hourHeight = scale.hourHeight(maxHeight)
+        val totalHeight = hourHeight * 24
         // Gutter and day column are two scroll viewports that SHARE one scroll
         // state, so they stay perfectly aligned. The day-column viewport is a
         // static, rounded-clipped window — the content scrolls inside it, so the
@@ -509,7 +513,7 @@ private fun Timeline(
                     Box(
                         modifier = Modifier
                             .fillMaxWidth()
-                            .height(HOUR_HEIGHT),
+                            .height(hourHeight),
                     ) {
                         if (h > 0) {
                             Text(
@@ -537,6 +541,7 @@ private fun Timeline(
                     dark = dark,
                     date = state.date,
                     today = state.today,
+                    hourHeight = hourHeight,
                     onEventClick = onEventClick,
                     onCreateAt = onCreateAt,
                     modifier = Modifier
@@ -554,11 +559,12 @@ private fun DayColumnCard(
     dark: Boolean,
     date: LocalDate,
     today: LocalDate,
+    hourHeight: Dp,
     onEventClick: (EventInstance) -> Unit,
     onCreateAt: (LocalDate, Int) -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    val hourPx = with(LocalDensity.current) { HOUR_HEIGHT.toPx() }
+    val hourPx = with(LocalDensity.current) { hourHeight.toPx() }
     val showHourLines = LocalShowHourLines.current
     val hourLineColor = MaterialTheme.colorScheme.outlineVariant
     Card(
@@ -587,14 +593,16 @@ private fun DayColumnCard(
                 },
         ) {
             val colWidth = maxWidth
+            val minEventHeight = hourHeight * MIN_EVENT_FRACTION
             blocks.forEach { block ->
                 val laneWidth = colWidth / block.laneCount
-                val top = HOUR_HEIGHT * (block.startMin / 60f)
-                val rawHeight = HOUR_HEIGHT * ((block.endMin - block.startMin) / 60f)
-                val height = if (rawHeight < MIN_EVENT_HEIGHT) MIN_EVENT_HEIGHT else rawHeight
+                val top = hourHeight * (block.startMin / 60f)
+                val rawHeight = hourHeight * ((block.endMin - block.startMin) / 60f)
+                val height = if (rawHeight < minEventHeight) minEventHeight else rawHeight
                 EventBlock(
                     block = block,
                     dark = dark,
+                    height = height,
                     onClick = { onEventClick(block.event) },
                     modifier = Modifier
                         .offset(x = laneWidth * block.lane, y = top)
@@ -605,7 +613,7 @@ private fun DayColumnCard(
             }
             // Current-time line, on top of the events, only on today's column.
             if (date == today) {
-                NowLine(date = date, hourHeight = HOUR_HEIGHT)
+                NowLine(date = date, hourHeight = hourHeight)
             }
         }
     }
@@ -615,6 +623,7 @@ private fun DayColumnCard(
 private fun EventBlock(
     block: TimedBlock,
     dark: Boolean,
+    height: Dp,
     onClick: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
@@ -623,7 +632,20 @@ private fun EventBlock(
     val locale = currentLocale()
     val timeLabel = "${minToHm(block.startMin, use24Hour, locale)}–" +
         minToHm(block.endMin, use24Hour, locale)
-    val showTime = block.endMin - block.startMin >= 45
+    val density = LocalDensity.current
+    val titleLineHeight = with(density) {
+        MaterialTheme.typography.labelMedium.lineHeight.toDp()
+    }
+    val timeLineHeight = with(density) {
+        MaterialTheme.typography.labelSmall.lineHeight.toDp()
+    }
+    // What's left for text once the 2.dp top/bottom padding is paid for. A block
+    // that cannot afford both lines spends its space on the title, and one too
+    // short even for that drops the title rather than serving a sliced one.
+    val available = height - 4.dp
+    val showTime = block.endMin - block.startMin >= 45 &&
+        available >= titleLineHeight + timeLineHeight
+    val showTitle = available >= titleLineHeight
     val soften = LocalSoftenColors.current
     val fill = eventFill(block.event.color, dark, soften)
     Box(
@@ -634,20 +656,22 @@ private fun EventBlock(
             .semantics { contentDescription = "$title, $timeLabel" },
     ) {
         Column {
-            Text(
-                text = title,
-                style = MaterialTheme.typography.labelMedium,
-                maxLines = if (showTime) 1 else 2,
-                overflow = TextOverflow.Ellipsis,
-                color = eventInk(fill, alpha = 0.85f),
-            )
+            if (showTitle) {
+                Text(
+                    text = title,
+                    style = MaterialTheme.typography.labelMedium,
+                    maxLines = if (showTime) 1 else 2,
+                    overflow = TextOverflow.Ellipsis,
+                    color = eventInk(fill, alpha = 0.85f),
+                )
+            }
             if (showTime) {
                 Text(
                     text = timeLabel,
                     style = MaterialTheme.typography.labelSmall,
                     maxLines = 1,
                     overflow = TextOverflow.Ellipsis,
-                    color = eventInk(fill, alpha = 0.6f),
+                    color = eventInk(fill, alpha = SECONDARY_INK_ALPHA),
                 )
             }
         }
@@ -656,17 +680,22 @@ private fun EventBlock(
 
 @Composable
 private fun DayLoading() {
-    val totalHeight = HOUR_HEIGHT * 24
+    val scale = LocalTimelineScale.current
     val scrollState = rememberScrollState()
-    Row(modifier = Modifier.fillMaxSize().verticalScroll(scrollState)) {
-        Spacer(Modifier.width(GUTTER_WIDTH))
-        Box(
-            modifier = Modifier
-                .weight(1f)
-                .height(totalHeight)
-                .padding(horizontal = 2.dp)
-                .background(MaterialTheme.colorScheme.surfaceContainer),
-        )
+    BoxWithConstraints(modifier = Modifier.fillMaxSize()) {
+        // Same scale resolution as the loaded timeline, so the skeleton's column
+        // doesn't resize the moment the real day arrives.
+        val totalHeight = scale.hourHeight(maxHeight) * 24
+        Row(modifier = Modifier.fillMaxSize().verticalScroll(scrollState)) {
+            Spacer(Modifier.width(GUTTER_WIDTH))
+            Box(
+                modifier = Modifier
+                    .weight(1f)
+                    .height(totalHeight)
+                    .padding(horizontal = 2.dp)
+                    .background(MaterialTheme.colorScheme.surfaceContainer),
+            )
+        }
     }
 }
 

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

@@ -100,6 +100,7 @@ import de.jeanlucmakiola.floret.identity.predictiveBack
 import de.jeanlucmakiola.calendula.ui.common.CalendarFailure
 import de.jeanlucmakiola.calendula.ui.common.icuTimeZoneRegion
 import de.jeanlucmakiola.calendula.ui.common.LocalSoftenColors
+import de.jeanlucmakiola.calendula.ui.common.eventAccent
 import de.jeanlucmakiola.calendula.ui.common.eventFill
 import de.jeanlucmakiola.floret.components.OptionCard
 import de.jeanlucmakiola.floret.locale.currentLocale
@@ -386,7 +387,7 @@ private fun EventDetailContent(state: EventDetailUiState.Success, modifier: Modi
     val instance = detail.instance
     val dark = isSystemInDarkTheme()
     val locale = currentDetailLocale()
-    val accent = eventFill(instance.color, dark, LocalSoftenColors.current)
+    val accent = eventAccent(instance.color, dark, LocalSoftenColors.current)
 
     Column(
         modifier = modifier

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

@@ -133,6 +133,7 @@ import de.jeanlucmakiola.calendula.ui.common.ColorSwatchRow
 import de.jeanlucmakiola.calendula.ui.common.TimeZonePickerDialog
 import de.jeanlucmakiola.calendula.ui.common.icuTimeZoneRegion
 import de.jeanlucmakiola.calendula.ui.common.LocalSoftenColors
+import de.jeanlucmakiola.calendula.ui.common.eventAccent
 import de.jeanlucmakiola.calendula.ui.common.eventFill
 import de.jeanlucmakiola.floret.components.DialogAmountField
 import de.jeanlucmakiola.floret.components.DialogUnitDropdown
@@ -563,7 +564,7 @@ private fun EventEditContent(
     // The accent ties the form to the detail screen's design language: the
     // bar under the title takes the target calendar's colour.
     val soften = LocalSoftenColors.current
-    val accent = selectedCalendar?.let { eventFill(it.color, dark, soften) }
+    val accent = selectedCalendar?.let { eventAccent(it.color, dark, soften) }
         ?: MaterialTheme.colorScheme.primary
     val gap = 12.dp
 

app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthScreen.kt

@@ -110,6 +110,7 @@ import de.jeanlucmakiola.calendula.ui.common.IMPLEMENTED_VIEWS
 import de.jeanlucmakiola.calendula.ui.common.EventDimAlpha
 import de.jeanlucmakiola.calendula.ui.common.LocalDimCutoff
 import de.jeanlucmakiola.calendula.ui.common.LocalSoftenColors
+import de.jeanlucmakiola.calendula.ui.common.eventAccent
 import de.jeanlucmakiola.calendula.ui.common.eventFill
 import de.jeanlucmakiola.calendula.ui.common.eventInk
 import de.jeanlucmakiola.calendula.ui.common.rememberCurrentMinute
@@ -1473,7 +1474,7 @@ private fun SplitDots(
                     .morphBounds(MonthMorphKey.Event(date, event.instanceId))
                     .size(SPLIT_DOT_SIZE)
                     .alpha(if (dimCutoff != null && event.hasEnded(dimCutoff)) EventDimAlpha else 1f)
-                    .background(eventFill(event.color, dark, soften), CircleShape),
+                    .background(eventAccent(event.color, dark, soften), CircleShape),
             )
         }
         if (hidden.isNotEmpty()) {
@@ -2098,7 +2099,7 @@ private fun OverflowDots(
                 modifier = Modifier
                     .size(6.dp)
                     .alpha(if (allEnded(byColor.getValue(argb), dimCutoff)) EventDimAlpha else 1f)
-                    .background(eventFill(argb, dark, soften), CircleShape),
+                    .background(eventAccent(argb, dark, soften), CircleShape),
             )
         }
         val extra = total - dots.size

app/src/main/java/de/jeanlucmakiola/calendula/ui/search/SearchScreen.kt

@@ -56,6 +56,7 @@ import de.jeanlucmakiola.floret.components.InlineTextField
 import de.jeanlucmakiola.floret.components.Position
 import de.jeanlucmakiola.floret.locale.currentLocale
 import de.jeanlucmakiola.calendula.ui.common.LocalSoftenColors
+import de.jeanlucmakiola.calendula.ui.common.eventAccent
 import de.jeanlucmakiola.calendula.ui.common.eventFill
 import de.jeanlucmakiola.calendula.domain.spanFirstDay
 import de.jeanlucmakiola.calendula.ui.common.LocalUse24HourFormat
@@ -208,7 +209,7 @@ private fun SearchResultRow(
                 modifier = Modifier
                     .size(width = 6.dp, height = 36.dp)
                     .clip(RoundedCornerShape(3.dp))
-                    .background(eventFill(event.color, dark, soften)),
+                    .background(eventAccent(event.color, dark, soften)),
             )
         },
         onClick = onClick,

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

@@ -13,6 +13,7 @@ import de.jeanlucmakiola.calendula.ui.agenda.AgendaRange
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
 import de.jeanlucmakiola.calendula.ui.common.IMPLEMENTED_VIEWS
 import de.jeanlucmakiola.calendula.ui.common.QuickSwitchConfig
+import de.jeanlucmakiola.calendula.ui.common.TimelineScale
 import de.jeanlucmakiola.calendula.ui.month.MonthViewStyle
 import de.jeanlucmakiola.calendula.widget.WidgetSize
 
@@ -57,6 +58,8 @@ data class SettingsUiState(
     val quickSwitchConfig: QuickSwitchConfig = QuickSwitchConfig.Default,
     /** How the Month view lays itself out: pages, continuous scroll, or split (#38, #53). */
     val monthViewStyle: MonthViewStyle = MonthViewStyle.Paged,
+    /** How tall an hour is drawn in the week and day timelines (#56). */
+    val timelineScale: TimelineScale = TimelineScale.Regular,
     /** Order of the views in the navigation drawer (#24); every view is always listed. */
     val drawerViewOrder: List<CalendarView> = IMPLEMENTED_VIEWS,
     /** Optional event-form fields shown by default (rest behind "more fields"). */

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

@@ -36,6 +36,7 @@ import de.jeanlucmakiola.calendula.ui.agenda.AgendaRange
 import de.jeanlucmakiola.calendula.ui.agenda.storageValue
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
 import de.jeanlucmakiola.calendula.ui.common.QuickSwitchConfig
+import de.jeanlucmakiola.calendula.ui.common.TimelineScale
 import de.jeanlucmakiola.calendula.ui.month.MonthViewStyle
 import de.jeanlucmakiola.calendula.ui.theme.AppFontSettings
 import de.jeanlucmakiola.calendula.ui.theme.FONT_CUSTOM_TOKEN
@@ -164,8 +165,9 @@ class SettingsViewModel @Inject constructor(
                     prefs.drawerViewOrder,
                     prefs.monthViewStyle,
                     prefs.widgetSize,
-                ) { quickSwitch, drawer, monthStyle, widgetSize ->
-                    ViewCustomization(quickSwitch, drawer, monthStyle, widgetSize)
+                    prefs.timelineScale,
+                ) { quickSwitch, drawer, monthStyle, widgetSize, timelineScale ->
+                    ViewCustomization(quickSwitch, drawer, monthStyle, widgetSize, timelineScale)
                 },
             ) { showRangeBar, autofocus, pastEvents, dimCompleted, viewCustomization ->
                 MiscSettings(showRangeBar, autofocus, pastEvents, dimCompleted, viewCustomization)
@@ -189,6 +191,7 @@ class SettingsViewModel @Inject constructor(
                 drawerViewOrder = misc.viewCustomization.drawerOrder,
                 monthViewStyle = misc.viewCustomization.monthViewStyle,
                 widgetSize = misc.viewCustomization.widgetSize,
+                timelineScale = misc.viewCustomization.timelineScale,
                 allowColorOnUnsupportedCalendars = defaults.allowColor,
                 defaultReminderMinutes = defaults.defaultReminder,
                 defaultAllDayReminderMinutes = defaults.allDayReminder,
@@ -295,6 +298,7 @@ class SettingsViewModel @Inject constructor(
         val drawerOrder: List<CalendarView>,
         val monthViewStyle: MonthViewStyle,
         val widgetSize: WidgetSize,
+        val timelineScale: TimelineScale,
     )
 
     /** Contact special-dates sub-page (issue #15); its own flow — the main state is full. */
@@ -581,6 +585,10 @@ class SettingsViewModel @Inject constructor(
         viewModelScope.launch { prefs.setMonthViewStyle(style) }
     }
 
+    fun setTimelineScale(scale: TimelineScale) {
+        viewModelScope.launch { prefs.setTimelineScale(scale) }
+    }
+
     fun setDrawerViewOrder(order: List<CalendarView>) {
         viewModelScope.launch { prefs.setDrawerViewOrder(order) }
     }

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

@@ -33,7 +33,9 @@ import de.jeanlucmakiola.calendula.ui.common.CalendarView
 import de.jeanlucmakiola.calendula.ui.common.IMPLEMENTED_VIEWS
 import de.jeanlucmakiola.calendula.ui.common.PickerDescription
 import de.jeanlucmakiola.calendula.ui.common.QuickSwitchConfig
+import de.jeanlucmakiola.calendula.ui.common.TimelineScale
 import de.jeanlucmakiola.calendula.ui.common.agendaRangeLabel
+import de.jeanlucmakiola.calendula.ui.common.descriptionRes
 import de.jeanlucmakiola.calendula.ui.common.formatTimeOfDay
 import de.jeanlucmakiola.calendula.ui.common.icon
 import de.jeanlucmakiola.calendula.ui.common.labelRes
@@ -68,6 +70,7 @@ internal fun ViewsScreen(
     var showTimeFormat by remember { mutableStateOf(false) }
     var showPastEvents by remember { mutableStateOf(false) }
     var showAgendaScreenRange by remember { mutableStateOf(false) }
+    var showTimelineScale by remember { mutableStateOf(false) }
 
     CollapsingScaffold(
         title = stringResource(R.string.settings_section_views),
@@ -144,10 +147,16 @@ internal fun ViewsScreen(
 
         Spacer(Modifier.height(8.dp))
         SectionHeader(stringResource(R.string.settings_week_day_header))
+        GroupedRow(
+            title = stringResource(R.string.settings_timeline_scale),
+            summary = stringResource(state.timelineScale.labelRes),
+            position = Position.Top,
+            onClick = { showTimelineScale = true },
+        )
         GroupedRow(
             title = stringResource(R.string.settings_hour_lines),
             summary = stringResource(R.string.settings_hour_lines_summary),
-            position = Position.Alone,
+            position = Position.Bottom,
             trailing = {
                 Switch(
                     checked = state.showHourLines,
@@ -321,6 +330,19 @@ internal fun ViewsScreen(
             onDismiss = { showPastEvents = false },
         )
     }
+    if (showTimelineScale) {
+        OptionPicker(
+            title = stringResource(R.string.settings_timeline_scale),
+            header = { PickerDescription(stringResource(R.string.settings_timeline_scale_hint)) },
+            predictiveBack = true,
+            options = TimelineScale.entries,
+            selected = state.timelineScale,
+            label = { stringResource(it.labelRes) },
+            summary = { stringResource(it.descriptionRes) },
+            onSelect = viewModel::setTimelineScale,
+            onDismiss = { showTimelineScale = false },
+        )
+    }
     if (showAgendaScreenRange) {
         AgendaRangePicker(
             title = stringResource(R.string.settings_agenda_range),

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

@@ -97,6 +97,11 @@ import de.jeanlucmakiola.floret.identity.rememberReduceMotion
 import de.jeanlucmakiola.floret.locale.currentLocale
 import de.jeanlucmakiola.calendula.ui.common.LocalUse24HourFormat
 import de.jeanlucmakiola.calendula.ui.common.LocalShowHourLines
+import de.jeanlucmakiola.calendula.ui.common.LocalTimelineScale
+import de.jeanlucmakiola.calendula.ui.common.MIN_EVENT_FRACTION
+import de.jeanlucmakiola.calendula.ui.common.MIN_TITLE_WRAP_WIDTH
+import de.jeanlucmakiola.calendula.ui.common.SECONDARY_INK_ALPHA
+import de.jeanlucmakiola.calendula.ui.common.hourHeight
 import de.jeanlucmakiola.calendula.ui.common.formatHourLabel
 import de.jeanlucmakiola.calendula.ui.common.formatMinuteOfDay
 import de.jeanlucmakiola.calendula.ui.common.hourSeparatorLines
@@ -113,15 +118,12 @@ import kotlinx.datetime.toLocalDateTime
 import kotlin.time.Clock
 import java.time.format.TextStyle as JavaTextStyle
 import java.util.Locale
-import kotlin.math.roundToInt
 
-private val HOUR_HEIGHT = 56.dp
 private val GUTTER_WIDTH = 48.dp
 /** Start inset for the gutter's content (week badge + hour labels) so it centres
  *  on the top bar's hamburger: with a 48dp gutter, 8dp lands the centre at 28dp
  *  (the app bar's 4dp inset + 24dp half icon button). */
 private val GUTTER_CONTENT_START_INSET = 8.dp
-private val MIN_EVENT_HEIGHT = 24.dp
 private val ALL_DAY_ROW_HEIGHT = 24.dp
 private val ALL_DAY_VERTICAL_PADDING = 6.dp
 
@@ -294,7 +296,6 @@ private fun WeekContent(
     onCreateAt: (LocalDate, Int) -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    val density = LocalDensity.current
     val slideSpec = rememberCalendarSlideSpec()
     val fadeSpec = rememberCalendarFadeSpec()
     val reduceMotion = rememberReduceMotion()
@@ -306,11 +307,9 @@ private fun WeekContent(
     val scrollState = rememberScrollState()
     LaunchedEffect(Unit) {
         snapshotFlow { scrollState.maxValue }.first { it > 0 }
-        val maxV = scrollState.maxValue
-        val target = with(density) {
-            (HOUR_HEIGHT.toPx() * 12 - (HOUR_HEIGHT.toPx() * 24 - maxV) / 2f).roundToInt()
-        }.coerceIn(0, maxV)
-        scrollState.scrollTo(target)
+        // Half the scroll range *is* noon: the content spans a full 24 hours, so
+        // centring the range centres midday at whatever hour height is in force.
+        scrollState.scrollTo(scrollState.maxValue / 2)
     }
 
     // Single, hoisted all-day strip height — shared by the outgoing and incoming
@@ -620,12 +619,17 @@ private fun Timeline(
     onEventClick: (EventInstance) -> Unit,
     onCreateAt: (LocalDate, Int) -> Unit,
 ) {
-    val totalHeight = HOUR_HEIGHT * 24
     val dark = isSystemInDarkTheme()
     val use24Hour = LocalUse24HourFormat.current
     val locale = currentLocale()
+    val scale = LocalTimelineScale.current
 
-    Box(modifier = Modifier.fillMaxSize()) {
+    // BoxWithConstraints rather than Box: the fit-the-whole-day scale needs the
+    // timeline's own viewport height, which is only known here — below the top
+    // bar, day header and all-day strip.
+    BoxWithConstraints(modifier = Modifier.fillMaxSize()) {
+        val hourHeight = scale.hourHeight(maxHeight)
+        val totalHeight = hourHeight * 24
         // Gutter and day columns are two scroll viewports that SHARE one scroll
         // state, so they stay perfectly aligned. The day-column viewport is a
         // static, rounded-clipped window — the content scrolls inside it, so the
@@ -645,7 +649,7 @@ private fun Timeline(
                     Box(
                         modifier = Modifier
                             .fillMaxWidth()
-                            .height(HOUR_HEIGHT),
+                            .height(hourHeight),
                     ) {
                         if (h > 0) {
                             Text(
@@ -680,6 +684,7 @@ private fun Timeline(
                             dark = dark,
                             date = day,
                             today = state.today,
+                            hourHeight = hourHeight,
                             onEventClick = onEventClick,
                             onCreateAt = onCreateAt,
                             modifier = Modifier
@@ -699,11 +704,12 @@ private fun DayColumnCard(
     dark: Boolean,
     date: LocalDate,
     today: LocalDate,
+    hourHeight: Dp,
     onEventClick: (EventInstance) -> Unit,
     onCreateAt: (LocalDate, Int) -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    val hourPx = with(LocalDensity.current) { HOUR_HEIGHT.toPx() }
+    val hourPx = with(LocalDensity.current) { hourHeight.toPx() }
     val showHourLines = LocalShowHourLines.current
     val hourLineColor = MaterialTheme.colorScheme.outlineVariant
     Card(
@@ -731,15 +737,17 @@ private fun DayColumnCard(
                 },
         ) {
             val colWidth = maxWidth
+            val minEventHeight = hourHeight * MIN_EVENT_FRACTION
             blocks.forEach { block ->
                 val laneWidth = colWidth / block.laneCount
-                val top = HOUR_HEIGHT * (block.startMin / 60f)
-                val rawHeight = HOUR_HEIGHT * ((block.endMin - block.startMin) / 60f)
-                val height = if (rawHeight < MIN_EVENT_HEIGHT) MIN_EVENT_HEIGHT else rawHeight
+                val top = hourHeight * (block.startMin / 60f)
+                val rawHeight = hourHeight * ((block.endMin - block.startMin) / 60f)
+                val height = if (rawHeight < minEventHeight) minEventHeight else rawHeight
                 EventBlock(
                     block = block,
                     dark = dark,
                     height = height,
+                    width = laneWidth,
                     onClick = { onEventClick(block.event) },
                     modifier = Modifier
                         .offset(x = laneWidth * block.lane, y = top)
@@ -750,7 +758,7 @@ private fun DayColumnCard(
             }
             // Current-time line, on top of the events, only on today's column.
             if (date == today) {
-                NowLine(date = date, hourHeight = HOUR_HEIGHT)
+                NowLine(date = date, hourHeight = hourHeight)
             }
         }
     }
@@ -761,6 +769,7 @@ private fun EventBlock(
     block: TimedBlock,
     dark: Boolean,
     height: Dp,
+    width: Dp,
     onClick: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
@@ -769,10 +778,6 @@ private fun EventBlock(
     val locale = currentLocale()
     val timeLabel = "${minToHm(block.startMin, use24Hour, locale)}–" +
         minToHm(block.endMin, use24Hour, locale)
-    // Only full-width (non-overlapping) blocks that are tall enough show the time.
-    // On narrow overlapping columns we drop it so the title can wrap to fill the
-    // whole block, mirroring Google Calendar.
-    val showTime = block.endMin - block.startMin >= 45 && block.laneCount == 1
     val density = LocalDensity.current
     val titleLineHeight = with(density) {
         MaterialTheme.typography.labelMedium.lineHeight.toDp()
@@ -780,11 +785,30 @@ private fun EventBlock(
     val timeLineHeight = with(density) {
         MaterialTheme.typography.labelSmall.lineHeight.toDp()
     }
-    // Wrap the title across as many lines as the block can fit (minus the 2.dp
-    // top/bottom padding and the reserved time line) instead of clipping it to a
-    // single character on slim, overlapping blocks.
-    val contentHeight = height - 4.dp - if (showTime) timeLineHeight else 0.dp
-    val titleMaxLines = (contentHeight / titleLineHeight).toInt().coerceAtLeast(1)
+    // What's left for text once the 2.dp top/bottom padding is paid for.
+    val available = height - 4.dp
+    // Only full-width (non-overlapping) blocks that are tall enough show the
+    // time. On narrow overlapping columns we drop it so the title can wrap to
+    // fill the whole block, mirroring Google Calendar — and a block that cannot
+    // afford both lines spends its space on the title.
+    val showTime = block.endMin - block.startMin >= 45 &&
+        block.laneCount == 1 &&
+        available >= titleLineHeight + timeLineHeight
+    // A short block drops the title rather than serving a horizontally sliced
+    // one: half a letter reads as a rendering fault, while a bare colour chip
+    // reads as what it is — an event too brief to label. Tap still opens it, and
+    // the semantics description carries the full title either way.
+    val showTitle = available >= titleLineHeight
+    // Wrap the title across as many lines as the block can fit — but only once a
+    // line is wide enough to hold more than a syllable. Below that the extra
+    // lines just stack fragments of the word, and one ellipsised line reads
+    // better.
+    val contentHeight = available - if (showTime) timeLineHeight else 0.dp
+    val titleMaxLines = if (width < MIN_TITLE_WRAP_WIDTH) {
+        1
+    } else {
+        (contentHeight / titleLineHeight).toInt().coerceAtLeast(1)
+    }
     val dimCutoff = LocalDimCutoff.current
     val dimmed = dimCutoff != null && block.event.hasEnded(dimCutoff)
     val soften = LocalSoftenColors.current
@@ -797,20 +821,22 @@ private fun EventBlock(
             .semantics { contentDescription = "$title, $timeLabel" },
     ) {
         Column {
-            Text(
-                text = title,
-                style = MaterialTheme.typography.labelMedium,
-                maxLines = titleMaxLines,
-                overflow = TextOverflow.Ellipsis,
-                color = eventInk(fill, alpha = 0.85f),
-            )
+            if (showTitle) {
+                Text(
+                    text = title,
+                    style = MaterialTheme.typography.labelMedium,
+                    maxLines = titleMaxLines,
+                    overflow = TextOverflow.Ellipsis,
+                    color = eventInk(fill, alpha = 0.85f),
+                )
+            }
             if (showTime) {
                 Text(
                     text = timeLabel,
                     style = MaterialTheme.typography.labelSmall,
                     maxLines = 1,
                     overflow = TextOverflow.Ellipsis,
-                    color = eventInk(fill, alpha = 0.6f),
+                    color = eventInk(fill, alpha = SECONDARY_INK_ALPHA),
                 )
             }
         }
@@ -819,7 +845,7 @@ private fun EventBlock(
 
 @Composable
 private fun WeekLoading() {
-    val totalHeight = HOUR_HEIGHT * 24
+    val scale = LocalTimelineScale.current
     val scrollState = rememberScrollState()
     Column(modifier = Modifier.fillMaxSize()) {
         // Header skeleton
@@ -838,16 +864,21 @@ private fun WeekLoading() {
                 )
             }
         }
-        Row(modifier = Modifier.fillMaxSize().verticalScroll(scrollState)) {
-            Spacer(Modifier.width(GUTTER_WIDTH))
-            repeat(7) {
-                Box(
-                    modifier = Modifier
-                        .weight(1f)
-                        .height(totalHeight)
-                        .padding(horizontal = 2.dp)
-                        .background(MaterialTheme.colorScheme.surfaceContainer),
-                )
+        BoxWithConstraints(modifier = Modifier.fillMaxSize()) {
+            // Same scale resolution as the loaded timeline, so the skeleton's
+            // columns don't resize the moment the real week arrives.
+            val totalHeight = scale.hourHeight(maxHeight) * 24
+            Row(modifier = Modifier.fillMaxSize().verticalScroll(scrollState)) {
+                Spacer(Modifier.width(GUTTER_WIDTH))
+                repeat(7) {
+                    Box(
+                        modifier = Modifier
+                            .weight(1f)
+                            .height(totalHeight)
+                            .padding(horizontal = 2.dp)
+                            .background(MaterialTheme.colorScheme.surfaceContainer),
+                    )
+                }
             }
         }
     }

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

@@ -58,6 +58,7 @@ import de.jeanlucmakiola.calendula.ui.common.CalendarView
 import de.jeanlucmakiola.calendula.ui.common.EventDimAlpha
 import de.jeanlucmakiola.calendula.ui.common.formatTimeOfDay
 import de.jeanlucmakiola.floret.locale.localizedDateFormatter
+import de.jeanlucmakiola.calendula.ui.common.eventAccent
 import de.jeanlucmakiola.calendula.ui.common.eventFill
 import de.jeanlucmakiola.calendula.widget.AgendaWidgetData
 import de.jeanlucmakiola.calendula.widget.CalendulaGlanceTheme
@@ -382,7 +383,7 @@ private fun EventRow(
     val title = event.title.ifBlank { context.getString(R.string.event_untitled) }
     // Glance has no generic alpha modifier, so dim by fading the colour stripe and
     // dropping both text lines to the lower-emphasis on-surface-variant tone.
-    val stripeColor = eventFill(event.color, dark, soften).let {
+    val stripeColor = eventAccent(event.color, dark, soften).let {
         if (dimmed) it.copy(alpha = EventDimAlpha) else it
     }
     val titleColor = if (dimmed) GlanceTheme.colors.onSurfaceVariant else GlanceTheme.colors.onSurface

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

@@ -330,8 +330,8 @@
     <string name="settings_default_view">Default view</string>
     <string name="settings_dynamic_color">Dynamic colour</string>
     <string name="settings_dynamic_color_unavailable">Requires Android 12 or newer</string>
-    <string name="settings_soften_colors">Soften calendar colours</string>
-    <string name="settings_soften_colors_summary">Tone calendar and event colours down to fit the theme. Turn off to show the raw colours from the calendar source.</string>
+    <string name="settings_soften_colors">Harmonise calendar colours</string>
+    <string name="settings_soften_colors_summary">Keep each calendar\'s hue but even out its brightness, so every event stays legible and the colours sit together. Turn off to show the raw colours from the calendar source.</string>
     <string name="settings_font_headings">Headings font</string>
     <string name="settings_font_body">Body font</string>
     <string name="settings_font_system">System default</string>
@@ -363,6 +363,16 @@
     <string name="settings_time_format_auto_summary">Following the system: %1$s</string>
     <string name="settings_hour_lines">Hour lines</string>
     <string name="settings_hour_lines_summary">Show a separator line at each hour in week and day view</string>
+    <string name="settings_timeline_scale">Hour height</string>
+    <string name="settings_timeline_scale_hint">How much vertical space one hour takes in week and day view. Both views share this setting.</string>
+    <string name="timeline_scale_fit_day">Fit whole day</string>
+    <string name="timeline_scale_fit_day_summary">All 24 hours on one screen, no scrolling</string>
+    <string name="timeline_scale_compact">Compact</string>
+    <string name="timeline_scale_compact_summary">More hours per screen, smaller blocks</string>
+    <string name="timeline_scale_regular">Regular</string>
+    <string name="timeline_scale_regular_summary">The standard spacing</string>
+    <string name="timeline_scale_comfortable">Comfortable</string>
+    <string name="timeline_scale_comfortable_summary">Roomier blocks, more scrolling</string>
     <string name="settings_dim_completed">Dim completed events</string>
     <string name="settings_dim_completed_summary">Fade events that have already ended in month and week view</string>
     <string name="settings_past_events">Past events</string>

app/src/test/java/de/jeanlucmakiola/calendula/data/prefs/SettingsPrefsTest.kt

@@ -13,6 +13,7 @@ import de.jeanlucmakiola.calendula.ui.agenda.AgendaRange
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
 import de.jeanlucmakiola.calendula.ui.common.IMPLEMENTED_VIEWS
 import de.jeanlucmakiola.calendula.ui.common.QuickSwitchConfig
+import de.jeanlucmakiola.calendula.ui.common.TimelineScale
 import de.jeanlucmakiola.calendula.ui.month.MonthViewStyle
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.test.runTest
@@ -98,6 +99,16 @@ class SettingsPrefsTest {
         assertThat(prefs.showHourLines.first()).isTrue()
     }
 
+    @Test
+    fun `timeline scale defaults to regular and round-trips`(@TempDir tempDir: Path) = runTest {
+        // Regular is the historical 56dp scale — an existing install that never
+        // opened the setting must keep the timeline it had (#56).
+        val prefs = SettingsPrefs(newDataStore(tempDir))
+        assertThat(prefs.timelineScale.first()).isEqualTo(TimelineScale.Regular)
+        prefs.setTimelineScale(TimelineScale.FitDay)
+        assertThat(prefs.timelineScale.first()).isEqualTo(TimelineScale.FitDay)
+    }
+
     @Test
     fun `week numbers default off and round-trips`(@TempDir tempDir: Path) = runTest {
         val prefs = SettingsPrefs(newDataStore(tempDir))

app/src/test/java/de/jeanlucmakiola/calendula/domain/EventColorPaletteTest.kt

@@ -74,10 +74,10 @@ class EventColorPaletteTest {
     }
 
     @Test
-    fun `neutrals collapse to one painted tint instead of a run of look-alikes`() {
-        // Black and every gray paint as the same pale swatch (the picker pins
-        // lightness and floors saturation), so only one survives — no stranded
-        // run of look-alike "pinks" at the end of the grid (#22).
+    fun `neutrals collapse instead of forming a run of look-alikes`() {
+        // Neutrals lose their hue entirely when painted, so they collapse onto
+        // the one or two greys the poles offer — a dark and a pale — instead of
+        // the old stranded run of look-alike "pinks" at the end of the grid (#22).
         val curated = listOf(
             EventColorOption("black", 0xFF000000.toInt()),
             EventColorOption("gray", 0xFF808080.toInt()),
@@ -86,8 +86,11 @@ class EventColorPaletteTest {
             EventColorOption("red", 0xFFFF0000.toInt()),
         ).curatedForPicker().map { it.key }
 
-        assertThat(curated).containsNoneOf("gray", "darkgray") // folded into black
+        assertThat(curated).doesNotContain("gray") // paints as black's grey
         assertThat(curated).containsAtLeast("black", "red", "blue")
+        // darkgray is light enough to keep a pale character, so the three
+        // neutrals still fold down to at most two swatches, never a run.
+        assertThat(curated.count { it in listOf("black", "gray", "darkgray") }).isAtMost(2)
     }
 
     @Test

app/src/test/java/de/jeanlucmakiola/calendula/domain/color/EventToneTest.kt

@@ -0,0 +1,159 @@
+package de.jeanlucmakiola.calendula.domain.color
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class EventToneTest {
+
+    /** Hues at full chroma, standing in for the provider colours in the wild. */
+    private val hues = (0 until 360 step 15).map { Oklch(0.65f, 0.2f, it.toFloat()).toArgb() }
+
+    private fun relativeLuminance(argb: Int): Double {
+        fun channel(shift: Int): Double {
+            val c = ((argb shr shift) and 0xFF) / 255.0
+            return if (c <= 0.04045) c / 12.92 else Math.pow((c + 0.055) / 1.055, 2.4)
+        }
+        return 0.2126 * channel(16) + 0.7152 * channel(8) + 0.0722 * channel(0)
+    }
+
+    private fun contrast(a: Int, b: Int): Double {
+        val hi = maxOf(relativeLuminance(a), relativeLuminance(b))
+        val lo = minOf(relativeLuminance(a), relativeLuminance(b))
+        return (hi + 0.05) / (lo + 0.05)
+    }
+
+    /** The other ink, for asserting the chosen one is the better of the two. */
+    private fun flip(ink: Int) =
+        if (ink == 0xFFFFFFFF.toInt()) 0xFF000000.toInt() else 0xFFFFFFFF.toInt()
+
+    /** [ink] over [fill] at [alpha], the way a title actually renders. */
+    private fun composite(ink: Int, fill: Int, alpha: Double): Int {
+        fun mix(shift: Int): Int {
+            val i = (ink shr shift) and 0xFF
+            val f = (fill shr shift) and 0xFF
+            return (alpha * i + (1 - alpha) * f).toInt().coerceIn(0, 255)
+        }
+        return (0xFF shl 24) or (mix(16) shl 16) or (mix(8) shl 8) or mix(0)
+    }
+
+    @Test
+    fun `hues of one lightness all get the same ink`() {
+        // The bug this replaced: at a pinned HSV value the hues straddled the ink
+        // crossover, so red took white while orange beside it took black. Ink may
+        // still differ by *pole*, but never by hue within a pole.
+        for (dark in listOf(false, true)) {
+            val inks = hues.map { eventTone(it, dark, harmonise = true).onContainer }.toSet()
+            assertThat(inks).containsExactly(0xFFFFFFFF.toInt())
+        }
+    }
+
+    @Test
+    fun `naturally light colours keep their character instead of turning muddy`() {
+        // Forcing every hue deep made a yellow into olive and a cream into brown.
+        // Pale sources stay pale — and then take dark ink.
+        for (pale in listOf(0xFFF6BF26, 0xFFFFF8DC, 0xFFF0E68C, 0xFFFFFFFF)) {
+            val tone = eventTone(pale.toInt(), dark = false, harmonise = true)
+            assertThat(oklchOf(tone.container).lightness).isGreaterThan(0.8f)
+            assertThat(tone.onContainer).isEqualTo(0xFF000000.toInt())
+        }
+    }
+
+    @Test
+    fun `warm mid colours still go deep, so orange reads as orange and not as cream`() {
+        // The threshold has to sit above orange: a burnt orange still says
+        // "orange", which is why it belongs on the deep pole with white ink.
+        // Note the ceiling this implies: a *bright* orange (#FF8C00, #FFA500) is
+        // genuinely a light colour and takes the light pole instead — forcing it
+        // deep is exactly what produced brown.
+        for (warm in listOf(0xFFF4511E, 0xFFE67C73, 0xFFD50000, 0xFFE65100)) {
+            val tone = eventTone(warm.toInt(), dark = false, harmonise = true)
+            assertThat(oklchOf(tone.container).lightness).isLessThan(0.6f)
+            assertThat(tone.onContainer).isEqualTo(0xFFFFFFFF.toInt())
+        }
+    }
+
+    @Test
+    fun `title ink clears WCAG AA on every hue`() {
+        for (dark in listOf(false, true)) {
+            for (hue in hues) {
+                val tone = eventTone(hue, dark, harmonise = true)
+                val ink = composite(tone.onContainer, tone.container, 0.85)
+                assertThat(contrast(tone.container, ink)).isGreaterThan(4.5)
+                assertThat(contrast(tone.container, ink))
+                    .isGreaterThan(contrast(tone.container, composite(flip(tone.onContainer), tone.container, 0.85)))
+            }
+        }
+    }
+
+    @Test
+    fun `the secondary line also clears WCAG AA on every hue`() {
+        for (dark in listOf(false, true)) {
+            for (hue in hues) {
+                val tone = eventTone(hue, dark, harmonise = true)
+                val ink = composite(tone.onContainer, tone.container, 0.8)
+                assertThat(contrast(tone.container, ink)).isGreaterThan(4.5)
+            }
+        }
+    }
+
+    @Test
+    fun `an accent stays visible against its own theme's surface`() {
+        // Accents carry no text, so the bar is WCAG's 3:1 for non-text contrast.
+        val lightSurface = 0xFFFEF7FF.toInt()
+        val darkSurface = 0xFF141218.toInt()
+        for ((dark, surface) in listOf(false to lightSurface, true to darkSurface)) {
+            for (hue in hues) {
+                val accent = eventTone(hue, dark, harmonise = true).accent
+                assertThat(contrast(accent, surface)).isGreaterThan(3.0)
+            }
+        }
+    }
+
+    @Test
+    fun `container and accent keep the same hue, so one calendar reads as one colour`() {
+        for (hue in hues) {
+            val tone = eventTone(hue, dark = false, harmonise = true)
+            assertThat(oklchOf(tone.accent).hue).isWithin(2f).of(oklchOf(tone.container).hue)
+        }
+    }
+
+    @Test
+    fun `orange no longer gets dark ink`() {
+        // The reported case: a plain orange calendar used to fall just above the
+        // crossover and take black text while its neighbours took white.
+        val tone = eventTone(0xFFF4511E.toInt(), dark = false, harmonise = true)
+        assertThat(tone.onContainer).isEqualTo(0xFFFFFFFF.toInt())
+    }
+
+    @Test
+    fun `different hues stay distinguishable`() {
+        val containers = hues.map { eventTone(it, dark = false, harmonise = true).container }
+        assertThat(containers.toSet()).hasSize(hues.size)
+    }
+
+    @Test
+    fun `a grey source stays grey rather than gaining an invented hue`() {
+        for (grey in listOf(0xFF000000, 0xFF808080, 0xFFFFFFFF, 0xFF9E9E9E)) {
+            val tone = eventTone(grey.toInt(), dark = false, harmonise = true)
+            assertThat(oklchOf(tone.container).chroma).isLessThan(0.01f)
+        }
+    }
+
+    @Test
+    fun `raw colours are painted verbatim when harmonising is off`() {
+        val raw = 0xFFF4511E.toInt()
+        val tone = eventTone(raw, dark = false, harmonise = false)
+        assertThat(tone.container).isEqualTo(raw)
+        assertThat(tone.accent).isEqualTo(raw)
+    }
+
+    @Test
+    fun `raw mode still picks a readable ink per colour`() {
+        // Nothing constrains what a provider sends, so the ink cannot be constant
+        // on this path the way it is for harmonised containers.
+        assertThat(eventTone(0xFF101010.toInt(), dark = false, harmonise = false).onContainer)
+            .isEqualTo(0xFFFFFFFF.toInt())
+        assertThat(eventTone(0xFFFFF6C0.toInt(), dark = false, harmonise = false).onContainer)
+            .isEqualTo(0xFF000000.toInt())
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/domain/color/OklchTest.kt

@@ -0,0 +1,64 @@
+package de.jeanlucmakiola.calendula.domain.color
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class OklchTest {
+
+    @Test
+    fun `matches Oklab's published anchors`() {
+        // Guards the conversion matrices against a transcription slip: these are
+        // Ottosson's own reference values for the space.
+        assertThat(oklchOf(0xFFFFFFFF.toInt()).lightness).isWithin(0.001f).of(1f)
+        assertThat(oklchOf(0xFF000000.toInt()).lightness).isWithin(0.001f).of(0f)
+        assertThat(oklchOf(0xFFFF0000.toInt()).lightness).isWithin(0.001f).of(0.6280f)
+    }
+
+    @Test
+    fun `white and black have no chroma`() {
+        assertThat(oklchOf(0xFFFFFFFF.toInt()).chroma).isWithin(0.001f).of(0f)
+        assertThat(oklchOf(0xFF000000.toInt()).chroma).isWithin(0.001f).of(0f)
+        assertThat(oklchOf(0xFF808080.toInt()).chroma).isWithin(0.001f).of(0f)
+    }
+
+    @Test
+    fun `converting to sRGB and back round-trips`() {
+        for (argb in listOf(0xFFF4511E, 0xFF039BE5, 0xFF0B8043, 0xFF8E24AA, 0xFFFBD75B)) {
+            val original = oklchOf(argb.toInt())
+            val roundTripped = oklchOf(original.toArgb())
+            assertThat(roundTripped.lightness).isWithin(0.01f).of(original.lightness)
+            assertThat(roundTripped.chroma).isWithin(0.01f).of(original.chroma)
+            assertThat(roundTripped.hue).isWithin(1f).of(original.hue)
+        }
+    }
+
+    @Test
+    fun `an out-of-gamut request keeps its lightness and gives up chroma`() {
+        // Most of the Oklch cylinder is outside sRGB. Lightness is the axis the
+        // contrast guarantees rest on, so it is the one that must survive.
+        val requested = Oklch(0.45f, 0.35f, 150f)
+        val actual = oklchOf(requested.toArgb())
+        assertThat(actual.lightness).isWithin(0.02f).of(requested.lightness)
+        assertThat(actual.chroma).isLessThan(requested.chroma)
+    }
+
+    @Test
+    fun `pinning lightness holds luminance far tighter than pinning HSV value did`() {
+        // The whole reason for the space swap. At a pinned HSV value the hues
+        // spread across relative luminance 0.10..0.45; pinned Oklch lightness
+        // must keep them in a narrow band, or one ink cannot serve them all.
+        val luminances = (0 until 360 step 15).map { hue ->
+            val argb = Oklch(0.45f, 0.16f, hue.toFloat()).toArgb()
+            relativeLuminance(argb)
+        }
+        assertThat(luminances.max() / luminances.min()).isLessThan(2.5)
+    }
+
+    private fun relativeLuminance(argb: Int): Double {
+        fun channel(shift: Int): Double {
+            val c = ((argb shr shift) and 0xFF) / 255.0
+            return if (c <= 0.04045) c / 12.92 else Math.pow((c + 0.055) / 1.055, 2.4)
+        }
+        return 0.2126 * channel(16) + 0.7152 * channel(8) + 0.0722 * channel(0)
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/ui/common/TimelineScaleTest.kt

@@ -0,0 +1,74 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.ui.unit.dp
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class TimelineScaleTest {
+
+    /** A Pixel-7-ish timeline viewport: what the issue reporter is looking at. */
+    private val phoneViewport = 670.dp
+
+    @Test
+    fun `Regular is the timeline's original 56dp constant`() {
+        // The default must not move: an install that never opens the setting has
+        // to keep the week and day views it already had (#56).
+        assertThat(TimelineScale.Regular.hourHeight(phoneViewport)).isEqualTo(56.dp)
+    }
+
+    @Test
+    fun `the fixed scales ignore the viewport`() {
+        for (scale in listOf(TimelineScale.Compact, TimelineScale.Regular, TimelineScale.Comfortable)) {
+            assertThat(scale.hourHeight(200.dp)).isEqualTo(scale.hourHeight(2000.dp))
+        }
+    }
+
+    @Test
+    fun `the fixed scales get taller in listed order`() {
+        assertThat(TimelineScale.Compact.hourHeight(phoneViewport))
+            .isLessThan(TimelineScale.Regular.hourHeight(phoneViewport))
+        assertThat(TimelineScale.Regular.hourHeight(phoneViewport))
+            .isLessThan(TimelineScale.Comfortable.hourHeight(phoneViewport))
+    }
+
+    @Test
+    fun `fit-day puts all 24 hours inside a phone viewport`() {
+        // The whole point of the issue: no vertical scrolling to see the day.
+        val h = TimelineScale.FitDay.hourHeight(phoneViewport)
+        assertThat(h * 24).isAtMost(phoneViewport)
+        // …and it uses the space, rather than leaving most of it empty.
+        assertThat(h * 24).isGreaterThan(phoneViewport * 0.9f)
+    }
+
+    @Test
+    fun `fit-day clamps instead of shrinking hours past legibility`() {
+        // A very short viewport (split screen, tiny device) would otherwise give
+        // hour rows too small for the gutter's 24 labels; the clamp wins and the
+        // timeline keeps a little scroll.
+        assertThat(TimelineScale.FitDay.hourHeight(120.dp)).isEqualTo(FIT_DAY_MIN)
+    }
+
+    @Test
+    fun `fit-day clamps instead of stretching hours on a very tall viewport`() {
+        assertThat(TimelineScale.FitDay.hourHeight(4000.dp)).isEqualTo(FIT_DAY_MAX)
+    }
+
+    @Test
+    fun `the minimum event height matches the old 24dp floor at the default scale`() {
+        // MIN_EVENT_FRACTION replaced a hardcoded 24dp; at Regular it must still
+        // land there, or short events change size for everyone who never touched
+        // the setting.
+        val floor = TimelineScale.Regular.hourHeight(phoneViewport) * MIN_EVENT_FRACTION
+        assertThat(floor.value).isWithin(0.5f).of(24f)
+    }
+
+    @Test
+    fun `the minimum event height stays a fixed share of an hour`() {
+        // A fixed dp floor would swallow ever more of the day as the scale drops;
+        // as a fraction it always means the same duration.
+        for (scale in TimelineScale.entries) {
+            val hour = scale.hourHeight(phoneViewport)
+            assertThat((hour * MIN_EVENT_FRACTION) / hour).isWithin(0.001f).of(MIN_EVENT_FRACTION)
+        }
+    }
+}