Smooth Discover hero handoffs and scope lane focus to each visit

app/src/test/java/org/justinvisser/wolfskin/tv/DiscoverRefreshMotionTest.kt

@@ -0,0 +1,114 @@
+package org.justinvisser.wolfskin.tv
+
+import android.app.Application
+import android.graphics.Bitmap
+import android.graphics.BitmapFactory
+import android.view.View
+import android.view.WindowManager
+import androidx.activity.ComponentActivity
+import androidx.compose.foundation.layout.requiredSize
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Rect
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import androidx.compose.ui.test.onNodeWithTag
+import androidx.compose.ui.test.onRoot
+import androidx.lifecycle.viewModelScope
+import com.github.damontecres.wholphin.preferences.AppPreferences
+import com.github.damontecres.wholphin.preferences.UserPreferences
+import com.github.damontecres.wholphin.services.NavigationManager
+import com.github.takahirom.roborazzi.captureRoboImage
+import io.mockk.coEvery
+import io.mockk.mockk
+import kotlinx.coroutines.CompletableDeferred
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.runBlocking
+import org.junit.Assert.*
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.justinvisser.wolfskin.conductarr.MemoryCacheStore
+import org.justinvisser.wolfskin.design.*
+import org.justinvisser.wolfskin.tv.read.TitleReadFacade
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.Shadows
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.GraphicsMode
+import java.io.File
+
+/** Refreshing a loaded Discover title must preserve its real header instead of rebuilding a skeleton. */
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [34], application = Application::class, qualifiers = "w960dp-h540dp-xhdpi")
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+class DiscoverRefreshMotionTest {
+    @get:Rule val rule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test fun loadedCatalogueRefreshKeepsReadyActionsOpaqueAndStationary() {
+        rule.activity.window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN)
+        @Suppress("DEPRECATION")
+        rule.activity.window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_FULLSCREEN or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION or View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
+        rule.mainClock.autoAdvance = false
+        FakeConductarr().use { fake ->
+            ConductarrSession(MemoryCacheStore()).use { session ->
+                session.select("server:shared", SHARED_TOKEN, fake.url)
+                runBlocking { session.authenticate() }
+                val facade = mockk<TitleReadFacade>()
+                coEvery { facade.findHeld(any(), any()) } returns null
+                val model = WolfskinTitleViewModel(rule.activity, facade, mockk(), NavigationManager(), session, mockk(relaxed = true))
+                val person = ShellPerson("shared", "Shared", "S", false)
+                val route = titleRoute("tv:44")
+                val shell = ShellState(listOf(person), person.key).apply { pickerVisible = false; enterDestination("discover"); enterDestination(route) }
+                val preferences = UserPreferences(AppPreferences.getDefaultInstance(), null)
+                val art = Bitmap.createBitmap(8, 8, Bitmap.Config.ARGB_8888).apply { eraseColor(android.graphics.Color.DKGRAY) }.asImageBitmap()
+                val refreshLookup = CompletableDeferred<java.util.UUID?>()
+                try {
+                    rule.setContent { WolfskinTheme {
+                        model.title?.let { state ->
+                            val bitmaps = listOfNotNull(state.data.item.poster, state.data.item.backdrop).associateWith { art }
+                            CompositionLocalProvider(LocalTitleBitmaps provides bitmaps) {
+                                TitleSurface(state, shell, Modifier.requiredSize(WolfskinTokens.Shell.stageWidth, WolfskinTokens.Shell.stageHeight))
+                            }
+                        }
+                    } }
+                    rule.runOnIdle { model.load(route, person, preferences, fixtures = false) }
+                    rule.waitUntil(30_000) {
+                        Shadows.shadowOf(android.os.Looper.getMainLooper()).idle()
+                        model.title?.data?.status == TitleReadStatus.Ready && model.title?.data?.cast?.isNotEmpty() == true && model.title?.data?.related?.isNotEmpty() == true
+                    }
+                    rule.mainClock.advanceTimeBy(640)
+                    val directory = File(System.getProperty("wolfskin.captureDirectory"), "discover-refresh").apply { mkdirs() }
+                    val bounds = rule.onNodeWithTag("title-actions").fetchSemanticsNode().boundsInRoot
+                    val pixels = IntArray(bounds.width.toInt() * bounds.height.toInt())
+                    val baseline = brightness(File(directory, "loaded.png"), bounds, pixels)
+                    coEvery { facade.findHeld(any(), any()) } coAnswers { refreshLookup.await() }
+                    rule.runOnIdle {
+                        model.load(route, person, preferences, fixtures = false, force = true)
+                        assertEquals("An already-loaded catalogue title must never emit Loading on refresh", TitleReadStatus.Ready, model.title!!.data.status)
+                    }
+                    repeat(12) { index ->
+                        rule.mainClock.advanceTimeBy(16)
+                        assertEquals(TitleReadStatus.Ready, model.title!!.data.status)
+                        assertFalse("A refresh cannot focus the root navigation", shell.navFocused)
+                        assertEquals("Loaded actions cannot replay their rise", bounds, rule.onNodeWithTag("title-actions").fetchSemanticsNode().boundsInRoot)
+                        assertEquals("Loaded actions cannot replay their fade", baseline, brightness(File(directory, "refresh-${index.toString().padStart(2, '0')}.png"), bounds, pixels))
+                    }
+                } finally {
+                    model.viewModelScope.cancel()
+                    refreshLookup.complete(null)
+                }
+            }
+        }
+    }
+
+    private fun brightness(file: File, bounds: Rect, pixels: IntArray): Long {
+        rule.onRoot().captureRoboImage(file.absolutePath)
+        val bitmap = BitmapFactory.decodeFile(file.absolutePath)
+        return try {
+            val width = bounds.width.toInt()
+            val height = bounds.height.toInt()
+            bitmap.getPixels(pixels, 0, width, bounds.left.toInt(), bounds.top.toInt(), width, height)
+            pixels.sumOf { (android.graphics.Color.red(it) + android.graphics.Color.green(it) + android.graphics.Color.blue(it)).toLong() }
+        } finally { bitmap.recycle() }
+    }
+}

data/tv-spec/spec.md

@@ -54,6 +54,8 @@ Read-only source measurement: Desperate Housewives has a 2732×1536 Backdrop. Wi
 
 Every Discover lane, including Movies for you, Series for you, service entries, service-specific lanes and Hidden picks, uses a **104 px heading band**: heading line plus **60 px heading-to-card gap**, up from 40 px. This is a consistent Level 2 extension, not a Series-only exception. Poster shelves become 652 px high and service-entry shelves 316 px. Captions and frame scroll offsets use the same heading band. Home headings remain unchanged.
 
+Round-2 Discover navigation amendment: Up/Down into an untouched lane starts at its leftmost item, not the previous lane's nearest column. A moved lane restores its own selected item and horizontal track for this visit. Pushed titles and service/collection pages preserve that visit; selecting another root tab or rebuilding Discover clears its lane positions. Root vertical position, filters and hero selection retain their existing shell policy. Home's nearest-centre shelves and Library's column-preserving continuous grids are unchanged pending a separate behavior decision.
+
 ## Motion and loading — revision 6
 
 Home heroes and shelves, Library rows, Discover hero/lanes, title headers, episodes and cast, and person headers/filmography use shaped placeholders without loading sentences. The placeholder fill is `surface2` (`#1b1b25`). A complete shelf shares **one** alpha layer: **0.55 → 1 → 0.55 over 1400 ms**, CSS ease-in-out (`.42,0,.58,1`), 700 ms each way. All loading shelves under the screen's theme share one clock, so late arrivals join the current phase. The clock stops when the last loading shelf leaves. No per-card clocks, staggered pulse phases, shimmer, moving gradient, or animated blur.
@@ -64,15 +66,16 @@ Home heroes and shelves, Library rows, Discover hero/lanes, title headers, episo
 | Poster caption in / out | 60 ms delay + 180 ms ease-out / 100 ms ease-out | 10 px rise on entry only; exit holds its position, including when entry was interrupted |
 | Network artwork only | 160 ms, Coil painter alpha | None; memory, disk and local hits are instant |
 | Row/tab content reveal | 180 ms, ease-out | One layer per row, 24 px rise |
-| Initial hero/title copy | 180 ms, ease-out | 16 px rise |
+| Initial title copy | 180 ms, ease-out | 16 px rise; already-loaded Home/Discover hero copy paints immediately |
 | Hero backdrop hand-off | 320 ms, ease-in-out (`.65,0,.35,1`) | Alpha only; retain previous art until incoming art or its final fallback is ready |
-| Hero copy hand-off | Old copy out 120 ms ease (`.25,.1,.25,1`); new copy starts at 140 ms and enters over 200 ms ease-out | 14 px rise on entry |
+| Hero copy hand-off | Incoming and outgoing alpha counter-fade over 200 ms ease-out, after artwork or final fallback is ready | 14 px rise for incoming copy only; interrupted outgoing copy holds its current translation |
 | Late ratings, genres, overview and readiness | 200 ms, ease | Alpha only, inside existing measured slots; rating plates keep their existing plate fade rather than adding a nested fade |
 | Horizontal / vertical focus-follow scroll | 160 ms ease / 180 ms ease-out | Existing scroll geometry |
+| Discover pager | 180 ms, ease-out, retargeting current width and opacity | Buttons and pager remain outside the copy transition; reduced motion snaps width and caps opacity fades at 80 ms |
 
-Row reveals are grouped rather than the browser prototype's per-card staging: the armv7 frame budget permits one animated layer per shelf, not one per card. Tabs have no full-screen transition layer. The upper Home hero blend is bounded to **1920×820 px**, Discover to **1920×740 px**; the lower backdrop changes without an animated screen-sized layer. Hero copy is a separate bounded block. Image reveal uses Coil's painter, not a new full-screen compositing layer. Existing poster-only blur is static.
+Row reveals are grouped rather than the browser prototype's per-card staging: the armv7 frame budget permits one animated layer per shelf, not one per card. Tabs have no full-screen transition layer. The upper Home hero blend is bounded to **1920×820 px**, Discover to **1920×740 px**; the lower backdrop changes without an animated screen-sized layer. Hero copy is a separate bounded block with stationary action controls. Ordinary image reveal uses Coil's painter; hero-controlled requests bypass that independent fade so only the token-backed hero blend owns the transition. Existing poster-only blur is static.
 
-The title page's scroll dim is a draw-only colour overlay, not an alpha-animated full-screen layer. Discover scrolls its backdrop through placement offsets rather than a full-screen translation layer. Initial loading animated layers are Home **2**, Library **up to 3** lazy rows, Discover **2**, title header **1**, person **2**; pending title episode/cast shelves add **1 each**, and each pending Discover lane owns **1**. Deep Home loading is bounded to **4** visible shelf layers. These are animated layers, not independent pulse clocks or every static display-list node: one shared pulse clock drives the loading screen without adding a layer. A hero hand-off adds at most **2** bounded owners (outgoing art and copy). Focus changes can animate **2** card transforms, **1** caption and at most **2** rating plates; artwork fades are painter draws without additional compositing layers. Late title metadata adds at most **4** bounded alpha layers: title ratings, play-target ratings, genres and overview. No animated owner is full-screen.
+The title page's scroll dim is a draw-only colour overlay, not an alpha-animated full-screen layer. Discover scrolls its backdrop through placement offsets rather than a full-screen translation layer. Initial loading animated layers are Home **2**, Library **up to 3** lazy rows, Discover **2**, title header **1**, person **2**; pending title episode/cast shelves add **1 each**, and each pending Discover lane owns **1**. Deep Home loading is bounded to **4** visible shelf layers. These are animated layers, not independent pulse clocks or every static display-list node: one shared pulse clock drives the loading screen without adding a layer. An ordinary hero hand-off animates **3** bounded owners (outgoing art and two copy blocks) above an opaque artwork base. Interruptions retain the painted composite without resetting alpha; each outgoing owner keeps its own original 320 ms artwork / 200 ms copy lifetime rather than restarting with later presses. Focus changes can animate **2** card transforms, **1** caption and at most **2** rating plates; ordinary artwork fades are painter draws without additional compositing layers. Late title metadata adds at most **4** bounded alpha layers: title ratings, play-target ratings, genres and overview. No animated owner is full-screen.
 
 The series readiness band reserves **56 px (28 dp)** from its first content paint, including when empty or when readiness later disappears. Ratings remain inside the fixed-height facts band. The series header's measured height therefore cannot change when late ratings/readiness arrive; overview, actions, season and episode anchors retain their coordinates. Skeletons have no click/hover focus targets; pending episode/cast rows remain absent from the key-navigation state until real cards exist. Initial loading keeps nav focus and Back still pops the title/person route.
 
@@ -82,6 +85,8 @@ Discover key traversal skips pending lanes in both directions. If every remainin
 
 Native **1920×1080** before/after frames and the frame-budget inventory are published at [the motion build proof](https://pages.justinvisser.org/wolfskin/tv-motion-build/). Before frames use the pre-change surface sources in this same isolated worktree; after frames use the shipped Compose surfaces. No device access, installation or optimized APK is part of this lane. On-box acceptance remains: no series layout change after first content, Home scrolling no worse than **39.6% janky / p90 65 ms**. Native JVM rendering does not measure that GPU/frame-timing target.
 
+The [round-2 Discover native proof](https://pages.justinvisser.org/wolfskin/tv-round2-discover/) publishes paired 1920×1080 frame strips and exact 16 ms alpha/translation/position series for ready, slow, failed, sustained rapid-selection and reduced-motion scenarios. Both versions use identical fixture data, immediate key-down/up, and the same selection timestamps. The regression suite checks an opaque artwork base, visible copy composite, monotonic per-layer transitions, stationary controls and token-bounded outgoing lifetimes. These are native-rendering proofs, not on-box frame-pacing measurements.
+
 
 ## Card metadata and bottom state line — revision 6, option B
 

wolfskin-design/src/main/java/org/justinvisser/wolfskin/design/DiscoverArtwork.kt

@@ -33,6 +33,8 @@ import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.testTag
 import coil3.compose.AsyncImage
 import org.justinvisser.wolfskin.design.WolfskinTokens.Color as C
+import coil3.request.transitionFactory
+import coil3.transition.Transition
 import org.justinvisser.wolfskin.design.WolfskinTokens.Discover as D
 import org.justinvisser.wolfskin.design.WolfskinTokens.Layout as L
 
@@ -50,13 +52,14 @@ fun DiscoverArtwork(path: String?, modifier: Modifier, poster: Boolean = false,
         this *= ColorMatrix().apply { setToScale(D.ambientBrightness, D.ambientBrightness, D.ambientBrightness, 1f) }
     }) else null }
     val context = LocalContext.current
-    val request = remember(context, path, poster, dim) {
+    val heroReady = LocalHeroArtReady.current
+    val request = remember(context, path, poster, dim, heroReady != null) {
         val upright = poster || dim
         WolfskinImages.request(context, path,
             if (upright) WolfskinTokens.Image.heroPosterRequestWidth else WolfskinTokens.Image.heroRequestWidth,
             if (upright) WolfskinTokens.Image.heroPosterRequestHeight else WolfskinTokens.Image.heroRequestHeight, upright)
+            .let { if (heroReady != null) it.newBuilder().transitionFactory(Transition.Factory.NONE).build() else it }
     }
-    val heroReady = LocalHeroArtReady.current
     if (painter != null) {
         androidx.compose.runtime.SideEffect { heroReady?.invoke() }
         Image(painter, null, modifier, contentScale = ContentScale.Crop, colorFilter = filter)

wolfskin-design/src/main/java/org/justinvisser/wolfskin/design/DiscoverScreen.kt

@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0-only
 package org.justinvisser.wolfskin.design
 
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.tween
 import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.launch
 
@@ -47,7 +49,10 @@ fun DiscoverScreen(state: DiscoverState, modifier: Modifier = Modifier) {
     val focus = remember(state) { object : ShellContentFocus by state {} }
     DisposableEffect(focus) {
         shell.contentFocus = focus
-        onDispose { if (shell.contentFocus === focus) { shell.contentFocus = null; shell.contentOverlayVisible = false } }
+        onDispose {
+            if (shell.tabs.getOrNull(shell.currentTab) != "discover") state.resetLaneMemory()
+            if (shell.contentFocus === focus) { shell.contentFocus = null; shell.contentOverlayVisible = false }
+        }
     }
     LaunchedEffect(shell.route, state.snapshot.savedAt) { shell.view.savedAt = state.snapshot.savedAt }
     LaunchedEffect(state.toast) { if (state.toast != null) { kotlinx.coroutines.delay(WolfskinTokens.Motion.toast.toLong()); state.toast = null } }
@@ -103,6 +108,7 @@ fun DiscoverScreen(state: DiscoverState, modifier: Modifier = Modifier) {
             animateFrameScroll(list, target - with(density) { current.toPx() } - list.firstVisibleItemScrollOffset)
         }
     }
+    HeroMotionScope {
     Box(modifier.fillMaxSize().testTag("discover-screen")) {
         if (state.hasHero && state.service == null && list.firstVisibleItemIndex == 0) state.hero?.let { title ->
             HeroArtCrossfade(title.key, title, L.row_phero, Modifier.offset { IntOffset(0, -list.firstVisibleItemScrollOffset) }) { DiscoverBackdrop(it) }
@@ -129,13 +135,15 @@ fun DiscoverScreen(state: DiscoverState, modifier: Modifier = Modifier) {
             }
         }
     }
+    }
 }
 
 @Composable
 private fun DiscoverHero(state: DiscoverState) {
     val title = state.hero ?: return
-    HeroCopyHandoff(title.key, title) { copy ->
+    Column(Modifier.fillMaxWidth().height(L.row_phero).padding(start = L.safeSide, bottom = L.heroCopyBottom), verticalArrangement = Arrangement.Bottom) {
-      Column(Modifier.fillMaxWidth().height(L.row_phero).padding(start = L.safeSide, bottom = L.heroCopyBottom), verticalArrangement = Arrangement.Bottom) {
+      HeroCopyHandoff(title.key, title) { copy ->
+       Column {
         Row(horizontalArrangement = Arrangement.spacedBy(WolfskinTokens.Card.posterGap), verticalAlignment = Alignment.CenterVertically) {
             Glyph("seerr", C.accentText, Modifier.size(L.buttonIcon))
             Text(if (state.snapshot.status == DiscoverStatus.Ready) "For you" else "Trending", color = C.accentText, style = DiscoverType.label)
@@ -151,17 +159,32 @@ private fun DiscoverHero(state: DiscoverState) {
         }
         Spacer(Modifier.height(D.heroMetaGap))
         Text(copy.overview, Modifier.width(L.heroOverviewMax), color = C.muted, style = DiscoverType.body, maxLines = 2, overflow = TextOverflow.Ellipsis)
+       }
+      }
         Spacer(Modifier.height(D.heroOverviewGap))
         Row(verticalAlignment = Alignment.CenterVertically) {
             DiscoverButton("Details", state.contentFocused && state.focusedRow == 0, "about") { state.openTitle(title) }
             Row(Modifier.padding(start = D.dotMargin), horizontalArrangement = Arrangement.spacedBy(D.dotGap), verticalAlignment = Alignment.CenterVertically) {
                 Glyph("left", C.fg.copy(alpha = if (state.contentFocused && state.focusedRow == 0) 1f else 0f), Modifier.size(D.dotChevron))
-                state.heroes.forEachIndexed { index, _ -> Box(Modifier.size(if (index == state.slide) D.dotActive else D.dotSize, D.dotSize).background(if (index == state.slide) C.fg else C.fg.copy(alpha = .3f), CircleShape)) }
+                state.heroes.forEachIndexed { index, _ -> DiscoverHeroDot(index, index == state.slide) }
                 Glyph("right", C.fg.copy(alpha = if (state.contentFocused && state.focusedRow == 0) 1f else 0f), Modifier.size(D.dotChevron))
             }
         }
     }
+}
+
+/** Pager geometry retargets from its current value independently of artwork loading. */
+@Composable
+private fun DiscoverHeroDot(index: Int, selected: Boolean) {
+    val progress = remember { Animatable(if (selected) 1f else 0f) }
+    val reduced = reducedMotion()
+    LaunchedEffect(selected, reduced) {
+        progress.animateTo(if (selected) 1f else 0f,
+            tween(motionDuration(WolfskinTokens.Motion.focusMove, reduced), easing = WolfskinTokens.Motion.easeOut))
     }
+    val widthProgress = if (reduced) { if (selected) 1f else 0f } else progress.value
+    Box(Modifier.testTag("hero-dot-$index").size(D.dotSize + (D.dotActive - D.dotSize) * widthProgress, D.dotSize)
+        .background(C.fg.copy(alpha = .3f + .7f * progress.value), CircleShape))
 }
 
 @Composable

wolfskin-design/src/main/java/org/justinvisser/wolfskin/design/DiscoverShelf.kt

@@ -40,14 +40,14 @@ fun DiscoverShelf(state: DiscoverState, lane: DiscoverLane, row: Int) {
     val height = if (services) K.entryH else K.posterH
     val cards = rememberLazyListState()
     val count = if (services) state.snapshot.services.size else lane.titles.size + if (lane.tail == DiscoverTail.None) 0 else 1
-    val column = (state.shell.view.cards[lane.id] ?: 0).coerceIn(0, (count - 1).coerceAtLeast(0))
+    val column = state.laneColumn(lane.id).coerceIn(0, (count - 1).coerceAtLeast(0))
     val active = state.contentFocused && state.focusedRow == row
     val slots = K.posterSlots
-    val first = state.shell.view.cards["first:${lane.id}"] ?: 0
+    val first = state.laneFirsts[lane.id] ?: 0
     val density = LocalDensity.current
-    LaunchedEffect(column, count, active) {
+    LaunchedEffect(state.service?.id, column, count, active) {
         val target = shelfFirst(column, first, slots, count)
-        state.shell.view.cards["first:${lane.id}"] = target
+        state.laneFirsts[lane.id] = target
         cards.scrollShelfTo(target, with(density) { K.posterPitch.toPx() })
     }
     Box(Modifier.fillMaxWidth().height(D.shelfHeadingBand + height + (if (services) WolfskinTokens.Shell.zero else K.posterCaptionBand) + L.rowGapAfter).testTag("discover-lane-${lane.id}")) {

wolfskin-design/src/main/java/org/justinvisser/wolfskin/design/DiscoverState.kt

@@ -10,7 +10,7 @@ import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
 
-/** One person owns a Discover view; the shell retains its root list and card memory. */
+/** Each person retains the root viewport; lane movement belongs only to this Discover visit. */
 class DiscoverState(
     val shell: ShellState,
     initial: DiscoverSnapshot,
@@ -75,6 +75,20 @@ class DiscoverState(
     private val pendingDismissals = mutableMapOf<String, DiscoverTitle?>()
     private var rootFilter = "all"
 
+    private val rootLaneMemory = DiscoverLaneMemory()
+    private val serviceLaneMemory = mutableMapOf<Long, DiscoverLaneMemory>()
+    private val laneMemory get() = service?.let { serviceLaneMemory.getValue(it.id) } ?: rootLaneMemory
+    private val laneColumns get() = laneMemory.columns
+    internal val laneFirsts get() = laneMemory.firsts
+
+    internal fun laneColumn(id: String): Int = laneColumns[id] ?: 0
+
+    /** Pushed titles preserve this visit; selecting another root tab discards lane movement. */
+    internal fun resetLaneMemory() {
+        rootLaneMemory.clear()
+        serviceLaneMemory.values.forEach { it.clear() }
+    }
+
     fun updateSnapshot(value: DiscoverSnapshot) {
         snapshot = value
         if (value.savedAt == null && value.status in setOf(DiscoverStatus.Ready, DiscoverStatus.NoSeeds, DiscoverStatus.PicksUnavailable)) savedTime = formatSavedTime()
@@ -139,7 +153,7 @@ class DiscoverState(
     val rowCount: Int get() = firstShelf + lanes.size
     val focusedRow: Int get() = shell.view.row.coerceIn(0, (rowCount - 1).coerceAtLeast(0))
     val focusedLane: DiscoverLane? get() = lanes.getOrNull(focusedRow - firstShelf)
-    val column: Int get() = shell.view.cards[rowKey].orZero().coerceAtMost(maxColumn())
+    val column: Int get() = (if (focusedRow >= firstShelf) laneColumn(rowKey) else shell.view.cards[rowKey].orZero()).coerceAtMost(maxColumn())
     val rowKey: String get() = when (focusedRow) { 0 -> "phero"; 1 -> "dchips"; else -> focusedLane?.id.orEmpty() }
     val isCard: Boolean get() = title == null && focusedRow >= firstShelf && focusedLane != null && focusedLane?.pending != true
     val contentFocused: Boolean get() = !shell.navFocused && !shell.pickerVisible && overlay == null
@@ -152,7 +166,8 @@ class DiscoverState(
 
     fun focus(row: Int, column: Int = 0) {
         shell.navFocused = false; shell.view.row = row
-        shell.view.cards[rowKey] = column.coerceIn(0, maxColumn())
+        val selected = column.coerceIn(0, maxColumn())
+        if (focusedRow >= firstShelf) laneColumns[rowKey] = selected else shell.view.cards[rowKey] = selected
     }
 
     private fun moveRow(direction: Int) {
@@ -161,10 +176,7 @@ class DiscoverState(
         if (target < if (hasHero) 0 else 1) { shell.focusNav(shell.currentTab); return }
         if (target >= rowCount) return
         val key = when (target) { 0 -> "phero"; 1 -> "dchips"; else -> lanes[target - firstShelf].id }
-        val nearest = if (focusedRow >= firstShelf && target >= firstShelf)
+        focus(target, if (target >= firstShelf) laneColumn(key) else shell.view.cards[key].orZero())
-            column - shell.view.cards["first:$rowKey"].orZero() + shell.view.cards["first:$key"].orZero()
-        else 0
-        focus(target, shell.view.cards[key] ?: nearest.coerceAtLeast(0))
     }
 
     fun openTitle(item: DiscoverTitle) {
@@ -225,12 +237,14 @@ class DiscoverState(
     fun isPick(item: DiscoverTitle): Boolean = snapshot.picks.any { it.key == item.key } || isHidden(item)
 
     fun openService(item: DiscoverService) {
+        serviceLaneMemory.getOrPut(item.id) { DiscoverLaneMemory() }
         rootFilter = filter; service = item; filter = "movie"; revision++
         onPush("discover-service/${item.id}")
         focus(firstShelf)
     }
 
     fun enterRoute(route: String) {
+        if (route in shell.tabs && route != "discover") resetLaneMemory()
         if (route == "discover") { title = null; collection = null; if (service != null) filter = rootFilter; service = null }
         else if (route.startsWith("discover-service") || route.startsWith("discover-see-all")) title = null
     }
@@ -261,6 +275,7 @@ class DiscoverState(
             ShellKey.Left, ShellKey.Right -> {
                 val direction = if (key == ShellKey.Left) -1 else 1
                 if (focusedRow == 0) slide = (slide + direction).coerceIn(0, (heroes.size - 1).coerceAtLeast(0))
+                else if (focusedRow >= firstShelf) laneColumns[rowKey] = (column + direction).coerceIn(0, maxColumn())
                 else shell.view.cards[rowKey] = (column + direction).coerceIn(0, maxColumn())
             }
             ShellKey.Ok -> when {
@@ -417,6 +432,12 @@ class DiscoverState(
     }
 }
 
+private class DiscoverLaneMemory {
+    val columns = mutableStateMapOf<String, Int>()
+    val firsts = mutableStateMapOf<String, Int>()
+    fun clear() { columns.clear(); firsts.clear() }
+}
+
 private fun Int?.orZero(): Int = this ?: 0
 
 private val DISCOVER_FILTERS = listOf("all", "movie", "tv")

wolfskin-design/src/main/java/org/justinvisser/wolfskin/design/HeroMotion.kt

@@ -6,95 +6,138 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.requiredSize
 import androidx.compose.foundation.layout.wrapContentSize
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.SideEffect
+import androidx.compose.runtime.compositionLocalOf
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.key
+import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
+import androidx.compose.runtime.snapshotFlow
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.graphicsLayer
-import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.platform.testTag
-import org.justinvisser.wolfskin.design.WolfskinTokens.Motion as M
+import androidx.compose.ui.semantics.SemanticsPropertyKey
-import kotlinx.coroutines.launch
+import androidx.compose.ui.semantics.semantics
-import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.unit.Dp
-import androidx.compose.runtime.compositionLocalOf
+import kotlinx.coroutines.coroutineScope
-import androidx.compose.runtime.rememberUpdatedState
-import androidx.compose.runtime.snapshotFlow
 import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.launch
+import org.justinvisser.wolfskin.design.WolfskinTokens.Motion as M
 
 /** Artwork success or its final fallback releases a pending hero hand-off. */
 internal val LocalHeroArtReady = compositionLocalOf<(() -> Unit)?> { null }
+internal val HeroLayerAlpha = SemanticsPropertyKey<Float>("HeroLayerAlpha")
+internal val HeroLayerTranslation = SemanticsPropertyKey<Float>("HeroLayerTranslation")
+internal val HeroLayerIdentity = SemanticsPropertyKey<String>("HeroLayerIdentity")
 
-/** Only the upper hero region blends; the lower backdrop changes without an animated screen layer. */
+private class HeroPresentation {
+    var identity by mutableStateOf<Any?>(null)
+}
+private val LocalHeroPresentation = compositionLocalOf<HeroPresentation?> { null }
+
+/** Artwork and copy share readiness without coupling either layer to a screen's selection state. */
+@Composable
+internal fun HeroMotionScope(content: @Composable () -> Unit) {
+    val presentation = remember { HeroPresentation() }
+    CompositionLocalProvider(LocalHeroPresentation provides presentation, content = content)
+}
+
+private class HeroLayer<T>(val identity: Any, var target: T, initialAlpha: Float) {
+    val alpha = Animatable(initialAlpha)
+    var ready by mutableStateOf(false)
+    var presented = false
+    var outgoing by mutableStateOf(false)
+}
+
+private class HeroCopyLayer<T>(val identity: Any, var target: T, initialAlpha: Float) {
+    val alpha = Animatable(initialAlpha)
+    val progress = Animatable(initialAlpha)
+    var outgoing by mutableStateOf(false)
+}
+
+/** Keep the painted composite while loading; interruptions fade each retained layer from its current alpha. */
 @Composable
 fun <T> HeroArtCrossfade(identity: Any, target: T, height: Dp, modifier: Modifier = Modifier, content: @Composable (T) -> Unit) {
-    var displayed by remember { mutableStateOf(target) }
+    val initial = remember { HeroLayer(identity, target, 1f).apply { presented = true } }
-    var displayedIdentity by remember { mutableStateOf(identity) }
+    val layers = remember { mutableStateListOf(initial) }
-    var outgoing by remember { mutableStateOf<T?>(null) }
+    val selected = remember(identity) { layers.firstOrNull { it.identity == identity && it.presented && !it.outgoing } ?: HeroLayer(identity, target, 1f) }
-    val alpha = remember { Animatable(0f) }
     val reduced = reducedMotion()
-    var readyIdentity by remember { mutableStateOf(identity) }
+    val presentation = LocalHeroPresentation.current
-    val latestIdentity by rememberUpdatedState(identity)
+    LaunchedEffect(selected, reduced) {
-    val onReady = remember(identity) { { if (latestIdentity == identity) readyIdentity = identity } }
+        layers.removeAll { it !== selected && !it.presented }
-    LaunchedEffect(identity, reduced) {
+        if (selected !in layers) layers.add(0, selected)
-        if (displayedIdentity != identity) {
+        snapshotFlow { selected.ready }.first { it }
-            outgoing = displayed
+        selected.presented = true
-            alpha.snapTo(1f)
+        presentation?.identity = identity
-            snapshotFlow { readyIdentity == identity }.first { it }
+        layers.forEach { if (it !== selected) it.outgoing = true }
-            displayed = target
-            displayedIdentity = identity
-        }
-        if (outgoing != null) {
-            alpha.animateTo(0f, tween(motionDuration(M.heroFade, reduced), easing = M.easeInOut))
-            outgoing = null
-        }
     }
     Box(modifier) {
-        CompositionLocalProvider(LocalHeroArtReady provides onReady) { content(target) }
+        layers.forEachIndexed { index, layer -> key(layer) {
-        outgoing?.let { old ->
+            SideEffect { if (layer.identity == identity) layer.target = target }
-            Box(Modifier.requiredSize(WolfskinTokens.Shell.stageWidth, height).graphicsLayer { this.alpha = alpha.value; clip = true }.testTag("hero-outgoing")) {
+            LaunchedEffect(layer.outgoing, reduced) {
-                Box(Modifier.wrapContentSize(Alignment.TopStart, unbounded = true).requiredSize(WolfskinTokens.Shell.stageWidth, WolfskinTokens.Shell.stageHeight)) { content(old) }
+                if (layer.outgoing) {
+                    layer.alpha.animateTo(0f, tween(motionDuration(M.heroFade, reduced), easing = M.easeInOut))
+                    layers.remove(layer)
+                }
             }
-        }
+            val outgoing = index != 0
+            val onReady = remember(layer) { { layer.ready = true } }
+            val bounds = if (outgoing) Modifier.requiredSize(WolfskinTokens.Shell.stageWidth, height) else Modifier
+            Box(bounds.graphicsLayer { alpha = layer.alpha.value; clip = outgoing }
+                .testTag(if (outgoing) "hero-outgoing" else "hero-incoming")
+                .semantics { this[HeroLayerAlpha] = layer.alpha.value; this[HeroLayerTranslation] = 0f; this[HeroLayerIdentity] = layer.identity.toString() }) {
+                CompositionLocalProvider(LocalHeroArtReady provides onReady) {
+                    Box(Modifier.wrapContentSize(Alignment.TopStart, unbounded = true).requiredSize(WolfskinTokens.Shell.stageWidth, WolfskinTokens.Shell.stageHeight)) {
+                        content(if (layer.identity == identity) target else layer.target)
+                    }
+                }
+            }
+        } }
     }
 }
 
-/** One bounded copy layer fades out, hands off, then rises; controls keep their logical owner. */
+/** Copy counter-fades after artwork is ready; outgoing blocks hold their current translation. */
 @Composable
 fun <T> HeroCopyHandoff(identity: Any, target: T, modifier: Modifier = Modifier, content: @Composable (T) -> Unit) {
+    val initial = remember { HeroCopyLayer(identity, target, 1f) }
+    val layers = remember { mutableStateListOf(initial) }
+    val selected = remember(identity) { layers.lastOrNull { it.identity == identity && !it.outgoing } ?: HeroCopyLayer(identity, target, 0f) }
     val reduced = reducedMotion()
-    val alpha = remember { Animatable(0f) }
+    val presentation = LocalHeroPresentation.current
-    val progress = remember { Animatable(0f) }
+    val rise = with(LocalDensity.current) { M.copyRise.toPx() }
-    var displayed by remember { mutableStateOf(target) }
+    LaunchedEffect(selected, reduced) {
-    var previous by remember { mutableStateOf(identity) }
+        if (selected !in layers) {
-    var handingOff by remember { mutableStateOf(false) }
+            if (presentation != null) snapshotFlow { presentation.identity == identity }.first { it }
-    var entered by remember { mutableStateOf(false) }
+            layers.add(selected)
-    val rise = with(androidx.compose.ui.platform.LocalDensity.current) { (if (entered) M.copyRise else M.copyEntryRise).toPx() }
+            layers.forEach { if (it !== selected) it.outgoing = true }
-    LaunchedEffect(identity, reduced) {
-        if (previous != identity || handingOff) {
-            handingOff = true
-            alpha.animateTo(0f, tween(motionDuration(M.heroCopyOut, reduced), easing = M.ease))
-            displayed = target
-            previous = identity
-            progress.snapTo(0f)
-            if (!reduced) kotlinx.coroutines.delay((M.heroCopyDelay - M.heroCopyOut).toLong())
-            kotlinx.coroutines.coroutineScope {
-                launch { alpha.animateTo(1f, tween(motionDuration(M.heroCopyIn, reduced), easing = M.easeOut)) }
-                launch { progress.animateTo(1f, tween(motionDuration(M.heroCopyIn, reduced), easing = M.easeOut)) }
-            }
-            handingOff = false
-        } else if (!entered) {
-            kotlinx.coroutines.coroutineScope {
-                launch { alpha.animateTo(1f, tween(motionDuration(M.rowEnter, reduced), easing = M.easeOut)) }
-                launch { progress.animateTo(1f, tween(motionDuration(M.rowEnter, reduced), easing = M.easeOut)) }
-            }
         }
-        entered = true
-        displayed = target
     }
-    Box(modifier.graphicsLayer { this.alpha = alpha.value; translationY = if (reduced) 0f else rise * (1f - progress.value) }) {
+    Box(modifier, contentAlignment = Alignment.BottomStart) {
-        content(if (handingOff || previous != identity) displayed else target)
+        layers.forEach { layer -> key(layer) {
+            SideEffect { if (layer.identity == identity) layer.target = target }
+            LaunchedEffect(layer.outgoing, reduced) {
+                if (layer.outgoing) {
+                    layer.alpha.animateTo(0f, tween(motionDuration(M.heroCopyIn, reduced), easing = M.easeOut))
+                    layers.remove(layer)
+                } else if (layer.alpha.value != 1f) coroutineScope {
+                    launch { layer.alpha.animateTo(1f, tween(motionDuration(M.heroCopyIn, reduced), easing = M.easeOut)) }
+                    launch { layer.progress.animateTo(1f, tween(motionDuration(M.heroCopyIn, reduced), easing = M.easeOut)) }
+                }
+            }
+            Box(Modifier.graphicsLayer {
+                alpha = layer.alpha.value
+                translationY = if (reduced) 0f else rise * (1f - layer.progress.value)
+            }.testTag(if (layer === layers.last()) "hero-copy" else "hero-copy-outgoing").semantics {
+                this[HeroLayerAlpha] = layer.alpha.value
+                this[HeroLayerTranslation] = if (reduced) 0f else rise * (1f - layer.progress.value)
+                this[HeroLayerIdentity] = layer.identity.toString()
+            }) { content(if (layer.identity == identity) target else layer.target) }
+        } }
     }
 }

wolfskin-design/src/main/java/org/justinvisser/wolfskin/design/HomeHeader.kt

@@ -19,6 +19,7 @@ import org.justinvisser.wolfskin.design.HomeType as T
 /** The hero occupies one row while its backdrop extends beneath the first shelves. */
 @Composable
 fun HomeHero(row: HomeRow, focused: Boolean, column: Int, ratings: List<HomeRating>, onButton: (Int) -> Unit, onHover: (Int) -> Unit) {
+    HeroMotionScope {
     Box(Modifier.fillMaxWidth().height(L.row_hero)) {
         if (!row.skeleton) {
             val title = row.cards.first()
@@ -28,7 +29,8 @@ fun HomeHero(row: HomeRow, focused: Boolean, column: Int, ratings: List<HomeRati
             }
             Box(artModifier.background(Brush.verticalGradient(0f to C.bg.copy(alpha = 0f), .52f to C.bg.copy(alpha = 0f), .74f to C.bg.copy(alpha = .6f), 1f to C.bg)))
             Box(artModifier.background(Brush.horizontalGradient(0f to C.bg.copy(alpha = .92f), .42f to C.bg.copy(alpha = .55f), .70f to C.bg.copy(alpha = 0f))))
-            HeroCopyHandoff(title.id, title, Modifier.align(Alignment.BottomStart).padding(start = L.safeSide, bottom = L.heroCopyBottom).width(L.heroCopyWidth)) { copy ->
+            Column(Modifier.align(Alignment.BottomStart).padding(start = L.safeSide, bottom = L.heroCopyBottom).width(L.heroCopyWidth)) {
+             HeroCopyHandoff(title.id, title) { copy ->
               Column {
                 Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(H.kickerGap)) {
                     Glyph(if (row.heroKind == "pick") "seerr" else "playback", C.accentText, Modifier.size(L.buttonIcon * (28f / 30f)))
@@ -44,6 +46,8 @@ fun HomeHero(row: HomeRow, focused: Boolean, column: Int, ratings: List<HomeRati
                 }
                 Spacer(Modifier.height(H.factsBottom))
                 Text(copy.overview, color = C.muted, style = T.body, maxLines = 2, overflow = TextOverflow.Ellipsis, modifier = Modifier.width(L.heroOverviewMax).exactLineBox(T.body))
+              }
+             }
                 Spacer(Modifier.height(H.overviewBottom))
                 Row(horizontalArrangement = Arrangement.spacedBy(L.buttonGap)) {
                     val detailsOnly = row.heroKind == "pick" || !row.watchReady
@@ -52,7 +56,6 @@ fun HomeHero(row: HomeRow, focused: Boolean, column: Int, ratings: List<HomeRati
                     if (!detailsOnly) PickerButton("Details", focused && column == 1, false, "about", onFocus = { onHover(1) }, textStyle = T.button) { onButton(1) }
                 }
             }
-            }
         } else {
             HomeAmbient(Modifier.wrapContentSize(Alignment.TopStart, unbounded = true).requiredSize(WolfskinTokens.Shell.stageWidth, WolfskinTokens.Shell.stageHeight))
             Column(Modifier.align(Alignment.BottomStart).padding(start = L.safeSide, bottom = L.heroCopyBottom).skeletonPulse()) {
@@ -64,6 +67,7 @@ fun HomeHero(row: HomeRow, focused: Boolean, column: Int, ratings: List<HomeRati
             }
         }
     }
+    }
 }
 
 /** Discover continues in the same scroller, under the active person's identity. */

wolfskin-design/src/main/java/org/justinvisser/wolfskin/design/TitleArtwork.kt

@@ -36,6 +36,8 @@ import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.tv.material3.Text
 import coil3.compose.AsyncImage
+import coil3.request.transitionFactory
+import coil3.transition.Transition
 import org.justinvisser.wolfskin.design.WolfskinTokens.Color as C
 import org.justinvisser.wolfskin.design.WolfskinTokens.Layout as L
 import org.justinvisser.wolfskin.design.WolfskinTokens.Title as D
@@ -54,8 +56,9 @@ fun TitleArtwork(path: String?, width: Int, height: Int, modifier: Modifier = Mo
     }
     else if (path != null) {
         val context = LocalContext.current
-        val request = remember(context, path, width, height, poster) {
+        val request = remember(context, path, width, height, poster, heroReady != null) {
             WolfskinImages.request(context, path, width, height, poster)
+                .let { if (heroReady != null) it.newBuilder().transitionFactory(Transition.Factory.NONE).build() else it }
         }
         AsyncImage(model = request, imageLoader = WolfskinImages.loader(context),
             contentDescription = null, modifier = modifier, contentScale = ContentScale.Crop, colorFilter = colorFilter,

wolfskin-design/src/test/java/org/justinvisser/wolfskin/design/DiscoverDetailsFocusTest.kt

@@ -0,0 +1,65 @@
+package org.justinvisser.wolfskin.design
+
+import android.app.Application
+import androidx.activity.ComponentActivity
+import androidx.compose.foundation.layout.requiredSize
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.input.key.Key
+import androidx.compose.ui.test.*
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import org.junit.Assert.*
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.GraphicsMode
+import org.robolectric.annotation.Config
+
+/** A catalogue read has no right to move the destination's focus into the root navigation. */
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [34], application = Application::class, qualifiers = "w960dp-h540dp-xhdpi")
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+class DiscoverDetailsFocusTest {
+    @get:Rule val rule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test fun heroDetailsRetainsDestinationFocusDuringLoadingAndLateMetadata() {
+        rule.mainClock.autoAdvance = false
+        val shell = ShellState(fixturePeople(), "justin").apply { pickerVisible = false; enterDestination("discover") }
+        val snapshot = discoverTestFixture().snapshot("justin")
+        val discover = DiscoverState(shell, snapshot, RecordingDiscoverOperations(snapshot, "justin"), CoroutineScope(Dispatchers.Main.immediate), shell::enterDestination)
+        val selected = requireNotNull(discover.hero)
+        val title = TitleState(TitlePageData(TitleItem(selected.key, selected.title, selected.type), status = TitleReadStatus.Loading), shell.person) {}
+        val art = android.graphics.Bitmap.createBitmap(8, 8, android.graphics.Bitmap.Config.ARGB_8888).apply { eraseColor(android.graphics.Color.DKGRAY) }.asImageBitmap()
+        rule.setContent { WolfskinTheme {
+          CompositionLocalProvider(LocalDiscoverArt provides { art }) {
+            val modifier = Modifier.requiredSize(WolfskinTokens.Shell.stageWidth, WolfskinTokens.Shell.stageHeight)
+            if (shell.route.startsWith("title/")) TitleSurface(title, shell, modifier)
+            else ShellSurface(shell, modifier) { DiscoverScreen(discover, it) }
+          }
+        } }
+        rule.mainClock.advanceTimeBy(640)
+        rule.onNodeWithTag("wolfskin-shell").performKeyInput { pressKey(Key.DirectionCenter) }
+        repeat(6) {
+            rule.mainClock.advanceTimeBy(16)
+            rule.waitForIdle()
+            assertFalse("Loading cannot steal destination focus on a later frame", shell.navFocused)
+        }
+        assertEquals("title/${android.net.Uri.encode(selected.key)}", shell.route)
+        assertFalse("The destination owns focus even while its read is pending", shell.navFocused)
+        rule.onRoot().performKeyInput { pressKey(Key.DirectionDown) }
+        assertFalse("Down on a loading title must not enter nav or a skeleton", shell.navFocused)
+        rule.runOnIdle { title.update(title.data.copy(status = TitleReadStatus.Ready)) }
+        rule.mainClock.advanceTimeBy(640)
+        val before = rule.onNodeWithTag("title-actions").fetchSemanticsNode().boundsInRoot
+        rule.runOnIdle { title.update(title.data.copy(item = title.data.item.copy(overview = "Late overview", ratings = listOf(LibraryRating("rt", 88.0))))) }
+        repeat(24) {
+            rule.mainClock.advanceTimeBy(16)
+            assertFalse(shell.navFocused)
+            assertEquals("Loaded actions cannot replay their entry or move after late metadata", before, rule.onNodeWithTag("title-actions").fetchSemanticsNode().boundsInRoot)
+        }
+    }
+}

wolfskin-design/src/test/java/org/justinvisser/wolfskin/design/DiscoverHeroSequenceTest.kt

@@ -0,0 +1,240 @@
+package org.justinvisser.wolfskin.design
+
+import android.app.Application
+import android.graphics.Bitmap
+import android.graphics.BitmapFactory
+import android.view.View
+import android.view.WindowManager
+import androidx.activity.ComponentActivity
+import androidx.compose.foundation.layout.requiredSize
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.input.key.Key
+import androidx.compose.ui.semantics.SemanticsProperties
+import androidx.compose.ui.test.*
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import coil3.intercept.Interceptor
+import coil3.request.ErrorResult
+import com.github.takahirom.roborazzi.captureRoboImage
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.awaitCancellation
+import org.json.JSONArray
+import org.json.JSONObject
+import org.junit.Assert.*
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.GraphicsMode
+import java.io.File
+import java.io.IOException
+
+/** Real Discover artwork, copy and pager are sampled on every manually advanced native frame. */
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [34], application = Application::class, qualifiers = "w960dp-h540dp-xhdpi")
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+class DiscoverHeroSequenceTest {
+    @get:Rule val rule = createAndroidComposeRule<ComponentActivity>()
+    private val samples = JSONArray()
+    private lateinit var directory: File
+    private lateinit var state: DiscoverState
+    private lateinit var shell: ShellState
+    private val artAvailable = mutableStateOf(true)
+    private val reduced = mutableStateOf(false)
+    private var previousPixel: Int? = null
+    private var largestJump = 0
+    private var previousLayers = emptyMap<String, Pair<Float, Float>>()
+    private val previousDotWidths = mutableMapOf<Int, Float>()
+    private var previousSelection: Int? = null
+
+    private fun launch(scenario: String, failedArt: Boolean = false) {
+        directory = File(System.getProperty("wolfskin.captureDirectory"), "discover-hero/$scenario").apply { mkdirs() }
+        rule.activity.window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN)
+        @Suppress("DEPRECATION")
+        rule.activity.window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_FULLSCREEN or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION or View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
+        rule.mainClock.autoAdvance = false
+        WolfskinImages.configureNetwork(rule.activity) { add(Interceptor { chain ->
+            if (chain.request.data.toString().startsWith("sequence:")) {
+                if (failedArt) ErrorResult(image = null, request = chain.request, throwable = IOException("Controlled artwork failure")) else awaitCancellation()
+            } else chain.proceed()
+        }) }
+        val fixture = discoverTestFixture()
+        val colors = listOf(android.graphics.Color.RED, android.graphics.Color.BLUE, android.graphics.Color.GREEN)
+        val titles = fixture.snapshot("justin").picks.take(3).mapIndexed { index, title ->
+            title.copy(backdrop = "sequence:$index", poster = null, posterOnly = false, score = 100.0 - index)
+        }
+        val art = colors.map { color -> Bitmap.createBitmap(8, 8, Bitmap.Config.ARGB_8888).apply { eraseColor(color) }.asImageBitmap() }
+        val snapshot = fixture.snapshot("justin").copy(picks = titles)
+        shell = ShellState(fixturePeople(), "justin").apply { pickerVisible = false; enterDestination("discover") }
+        state = DiscoverState(shell, snapshot, RecordingDiscoverOperations(snapshot, "justin"), CoroutineScope(Dispatchers.Main.immediate), shell::enterDestination)
+        rule.setContent { WolfskinTheme {
+            CompositionLocalProvider(LocalReducedMotion provides reduced.value, LocalDiscoverArt provides { path ->
+                path.removePrefix("sequence:").toIntOrNull()?.let { if (it != 1 || artAvailable.value) art[it] else null }
+            }) {
+                ShellSurface(shell, Modifier.requiredSize(WolfskinTokens.Shell.stageWidth, WolfskinTokens.Shell.stageHeight)) { DiscoverScreen(state, it) }
+            }
+        } }
+        rule.mainClock.advanceTimeBy(640)
+    }
+
+    @Test fun interruptedHeroNeverSnapsToAnIntermediateSelection() {
+        launch("interrupted")
+        sample("settled", 0)
+        press(Key.DirectionRight)
+        frames("first", 12)
+        press(Key.DirectionRight)
+        frames("interrupted", 28)
+        press(Key.DirectionLeft)
+        frames("reverse", 28)
+        finish()
+        assertSmoothPixels()
+        assertEquals(1, state.slide)
+    }
+
+    @Test fun slowArtRetainsBothThePaintedHeroAndItsCopyUntilReady() {
+        launch("slow")
+        sample("settled", 0)
+        val original = previousPixel
+        rule.runOnIdle { artAvailable.value = false }
+        press(Key.DirectionRight)
+        frames("pending", 24)
+        assertEquals("Pending art must not replace the painted backdrop", original, previousPixel)
+        assertEquals(state.heroes.first().key, copyIdentities().single())
+        rule.runOnIdle { artAvailable.value = true }
+        frames("ready", 28)
+        finish()
+        assertSmoothPixels()
+        assertEquals(state.hero!!.key, copyIdentities().single())
+    }
+
+    @Test fun failedArtBlendsToItsFinalFallbackWithoutErasingThePreviousHero() {
+        launch("failed", failedArt = true)
+        sample("settled", 0)
+        rule.runOnIdle { artAvailable.value = false }
+        press(Key.DirectionRight)
+        frames("fallback", 28)
+        rule.onNodeWithTag("discover-missing-art").assertExists()
+        finish()
+        assertSmoothPixels()
+        assertEquals(state.hero!!.key, copyIdentities().single())
+    }
+
+    @Test fun repeatedPressesRetargetTheCurrentCompositeWithoutSnapBack() {
+        launch("rapid")
+        sample("settled", 0)
+        listOf(Key.DirectionRight, Key.DirectionRight, Key.DirectionLeft, Key.DirectionLeft, Key.DirectionRight, Key.DirectionRight).forEachIndexed { index, key ->
+            press(key)
+            frames("press-$index", 3)
+        }
+        repeat(48) { index ->
+            press(if (index % 2 == 0) Key.DirectionLeft else Key.DirectionRight)
+            frames("burst-$index", 1)
+        }
+        frames("settled-latest", 28)
+        finish()
+        assertSmoothPixels()
+        assertEquals(state.hero!!.key, copyIdentities().single())
+    }
+
+    @Test fun reducedMotionKeepsTheBlendButRemovesCopyTranslation() {
+        launch("reduced")
+        rule.runOnIdle { reduced.value = true }
+        press(Key.DirectionRight)
+        frames("reduced", (WolfskinTokens.Motion.heroFade + 15) / 16)
+        finish()
+        assertEquals(state.hero!!.key, copyIdentities().single())
+        assertEquals(1, rule.onAllNodesWithTag("hero-incoming", useUnmergedTree = true).fetchSemanticsNodes().size)
+        assertTrue(rule.onAllNodesWithTag("hero-outgoing", useUnmergedTree = true).fetchSemanticsNodes().isEmpty())
+        val moving = (0 until samples.length()).map(samples::getJSONObject).filter { row ->
+            val layers = row.getJSONArray("layers")
+            (0 until layers.length()).map(layers::getJSONObject).any {
+                it.getString("kind") == "hero-outgoing" && it.getDouble("alpha") > 0.0 && it.getDouble("alpha") < 1.0
+            }
+        }.map { it.getLong("timeMs") }
+        assertTrue("Reduced artwork fade cannot retain the ordinary 320ms lifetime", moving.last() - moving.first() <= WolfskinTokens.Motion.reducedFade)
+    }
+
+    private fun copyIdentities() = rule.onAllNodesWithTag("hero-copy", useUnmergedTree = true).fetchSemanticsNodes().map { it.config[HeroLayerIdentity] }
+    private fun press(key: Key) = rule.onNodeWithTag("wolfskin-shell").performKeyInput { keyDown(key); keyUp(key) }
+    private fun frames(phase: String, count: Int) = repeat(count) { index -> rule.mainClock.advanceTimeBy(16); sample(phase, index) }
+    private fun finish() = File(directory, "series.json").writeText(samples.toString(2))
+    private fun assertSmoothPixels() = assertTrue("A 16ms hero frame cannot snap to a full intermediate selection; largest channel jump=$largestJump", largestJump <= 48)
+
+    private fun sample(phase: String, index: Int) {
+        rule.waitForIdle()
+        val file = File(directory, "$phase-${index.toString().padStart(2, '0')}.png")
+        rule.onRoot().captureRoboImage(file.absolutePath)
+        val bitmap = BitmapFactory.decodeFile(file.absolutePath)
+        val pixel = try { bitmap.getPixel(1600, 200) } finally { bitmap.recycle() }
+        val channels = channels(pixel)
+        previousPixel?.let { old -> largestJump = maxOf(largestJump, channels.zip(channels(old)).maxOf { (a, b) -> kotlin.math.abs(a - b) }) }
+        previousPixel = pixel
+        val copy = JSONArray()
+        state.heroes.forEach { title -> rule.onAllNodesWithText(title.title, useUnmergedTree = true).fetchSemanticsNodes().forEach { node ->
+            copy.put(JSONObject().put("title", title.key).put("x", node.boundsInRoot.left).put("y", node.boundsInRoot.top))
+        } }
+        val layers = layerSamples()
+        val dots = JSONArray()
+        state.heroes.indices.forEach { dot -> rule.onAllNodesWithTag("hero-dot-$dot", useUnmergedTree = true).fetchSemanticsNodes().forEach { node ->
+            previousDotWidths[dot]?.let { previous ->
+                val range = with(rule.density) { (WolfskinTokens.Discover.dotActive - WolfskinTokens.Discover.dotSize).toPx() }
+                if (!reduced.value) assertTrue("Pager retarget must not snap a full dot-width step", kotlin.math.abs(node.boundsInRoot.width - previous) <= range / 2)
+                if (reduced.value) {
+                    val rest = with(rule.density) { WolfskinTokens.Discover.dotSize.toPx() }
+                    assertTrue("Reduced motion snaps pager geometry instead of moving it", node.boundsInRoot.width == rest || node.boundsInRoot.width == rest + range)
+                }
+                if (previousSelection == state.slide) {
+                    if (dot == state.slide) assertTrue("The selected pager dot cannot shrink backwards", node.boundsInRoot.width >= previous - .01f)
+                    else assertTrue("An outgoing pager dot cannot grow backwards", node.boundsInRoot.width <= previous + .01f)
+                }
+            }
+            previousDotWidths[dot] = node.boundsInRoot.width
+            dots.put(JSONObject().put("index", dot).put("x", node.boundsInRoot.left).put("y", node.boundsInRoot.top).put("width", node.boundsInRoot.width))
+        } }
+        previousSelection = state.slide
+        samples.put(JSONObject().put("phase", phase).put("frame", index).put("timeMs", rule.mainClock.currentTime)
+            .put("selection", state.slide).put("rgb", JSONArray(channels)).put("copy", copy).put("layers", layers).put("dots", dots).put("navFocused", shell.navFocused))
+    }
+
+    private fun layerSamples(): JSONArray {
+        val result = JSONArray()
+        val current = mutableMapOf<String, Pair<Float, Float>>()
+        val nodes = rule.onAllNodes(SemanticsMatcher.keyIsDefined(HeroLayerAlpha), useUnmergedTree = true).fetchSemanticsNodes()
+        val unique = nodes.groupBy { it.config[SemanticsProperties.TestTag] + ":" + it.id }
+        assertTrue("The artwork composite always has an opaque base", nodes.any { it.config[SemanticsProperties.TestTag] == "hero-incoming" && it.config[HeroLayerAlpha] == 1f })
+        val copyResidual = nodes.filter { it.config[SemanticsProperties.TestTag].startsWith("hero-copy") }
+            .fold(1f) { residual, node -> residual * (1f - node.config[HeroLayerAlpha]) }
+        assertTrue("Copy composite cannot fade through a blank frame", 1f - copyResidual >= .5f)
+        val artCount = nodes.count { !it.config[SemanticsProperties.TestTag].startsWith("hero-copy") }
+        val copyCount = nodes.size - artCount
+        assertTrue("Sustained presses cannot extend outgoing art lifetimes", artCount <= (WolfskinTokens.Motion.heroFade + 15) / 16 + 3)
+        assertTrue("Sustained presses cannot accumulate outgoing copy layers", copyCount <= (WolfskinTokens.Motion.heroCopyIn + 15) / 16 + 3)
+        unique.forEach { (key, matching) -> matching.forEach { node ->
+            val alpha = node.config[HeroLayerAlpha]
+            val translation = node.config[HeroLayerTranslation]
+            val tag = node.config[SemanticsProperties.TestTag]
+            if (matching.size == 1) {
+                previousLayers[key]?.let { (previousAlpha, previousTranslation) ->
+                    if (tag == "hero-outgoing" || tag == "hero-copy-outgoing") assertTrue("Outgoing layers cannot restart at full opacity: $key", alpha <= previousAlpha + .001f)
+                    if (tag == "hero-copy-outgoing") assertEquals("Outgoing copy must fade where its entry stopped", previousTranslation, translation, .001f)
+                    if (tag == "hero-copy") {
+                        assertTrue("Copy alpha cannot snap backwards: $key", alpha >= previousAlpha - .001f)
+                        assertTrue("Copy translation cannot snap backwards: $key", translation <= previousTranslation + .001f)
+                    }
+                }
+                current[key] = alpha to translation
+            }
+            if (reduced.value) assertEquals(0f, translation, .001f)
+            result.put(JSONObject().put("kind", tag).put("identity", node.config[HeroLayerIdentity]).put("layerId", node.id).put("alpha", alpha)
+                .put("translationY", translation).put("x", node.boundsInRoot.left).put("y", node.boundsInRoot.top))
+        } }
+        previousLayers = current
+        return result
+    }
+
+    private fun channels(pixel: Int) = listOf(android.graphics.Color.red(pixel), android.graphics.Color.green(pixel), android.graphics.Color.blue(pixel))
+}

wolfskin-design/src/test/java/org/justinvisser/wolfskin/design/DiscoverKeysTest.kt

@@ -2,6 +2,9 @@
 package org.justinvisser.wolfskin.design
 
 import android.app.Application
+import android.graphics.Bitmap
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.graphics.asImageBitmap
 import android.view.KeyEvent as AndroidKeyEvent
 import androidx.compose.ui.input.key.Key
 import androidx.compose.ui.input.key.KeyEvent
@@ -19,10 +22,12 @@ import org.junit.Test
 import org.junit.runner.RunWith
 import org.robolectric.RobolectricTestRunner
 import org.robolectric.annotation.Config
+import org.robolectric.annotation.GraphicsMode
 
 /** Acceptance data drives real Android events through the shell's production focus adapter. */
 @RunWith(RobolectricTestRunner::class)
 @Config(sdk = [34], application = Application::class, qualifiers = "w960dp-h540dp-xhdpi")
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
 class DiscoverKeysTest {
     @get:Rule val rule = createComposeRule()
     private val fixture = discoverTestFixture()
@@ -33,11 +38,14 @@ class DiscoverKeysTest {
         { shell.enterDestination("discover") }, fixture::service)
 
     private fun launch() {
+        val art = Bitmap.createBitmap(8, 8, Bitmap.Config.ARGB_8888).apply { eraseColor(android.graphics.Color.DKGRAY) }.asImageBitmap()
         rule.setContent {
             WolfskinTheme {
+             CompositionLocalProvider(LocalDiscoverArt provides { art }) {
                 ShellSurface(shell, overlay = { DiscoverOverlay(state) }) { modifier ->
                     if (shell.route == "discover" || shell.route.startsWith("discover-") || shell.route.startsWith("title/")) DiscoverScreen(state, modifier) else ShellPlaceholder(shell.route, modifier)
                 }
+             }
             }
         }
     }
@@ -256,7 +264,69 @@ class DiscoverKeysTest {
         assertNull(state.collection)
         assertSame(origin, shell.view)
         assertEquals(3, shell.view.row)
-        assertEquals(2, shell.view.cards[state.rowKey])
+        assertEquals(2, state.column)
+    }
+
+    @Test fun firstEntryStartsLeftmostAndOnlyMovedLanesRememberTheirPosition() {
+        replay("Open Discover")
+        press(Key.DirectionDown, Key.DirectionDown)
+        assertEquals(0, state.column)
+        repeat(7) { press(Key.DirectionRight) }
+        val moved = state.column
+        assertTrue(moved > 0)
+        press(Key.DirectionDown)
+        assertEquals("An untouched lane starts at its own left edge, not the previous lane's column", 0, state.column)
+        press(Key.DirectionUp)
+        assertEquals(moved, state.column)
+    }
+
+    @Test fun leavingTheTabResetsLaneMovementButPushedTitlesDoNot() {
+        replay("Open Discover")
+        press(Key.DirectionDown, Key.DirectionDown)
+        press(Key.DirectionDown)
+        repeat(4) { press(Key.DirectionRight) }
+        val row = state.focusedRow
+        val moved = state.column
+        press(Key.DirectionCenter)
+        assertNotNull("This round trip must open a title, not a service lane", state.title)
+        press(Key.Back)
+        assertEquals(moved, state.column)
+        press(Key.Back)
+        press(Key.DirectionLeft, Key.DirectionCenter)
+        assertEquals("home", shell.route)
+        press(Key.DirectionUp, Key.DirectionRight)
+        press(Key.DirectionCenter)
+        assertEquals("discover", shell.route)
+        assertEquals(row, state.focusedRow)
+        assertEquals(0, state.column)
+        assertEquals(0, state.laneFirsts[state.rowKey] ?: 0)
+    }
+
+    @Test fun rebuildingDiscoverDoesNotReuseThePreviousInstancesLaneColumns() {
+        shell.pickerVisible = false
+        shell.enterDestination("discover")
+        state.focus(state.firstShelf, 4)
+        val rebuilt = DiscoverState(shell, snapshot, operations, CoroutineScope(Dispatchers.Main.immediate))
+        assertEquals(0, rebuilt.column)
+    }
+
+    @Test fun serviceLanesKeepIndependentPositionsAndResetWithTheRootVisit() {
+        shell.pickerVisible = false
+        shell.enterDestination("discover")
+        state.focus(state.firstShelf + 1, 3)
+        state.openService(snapshot.services[0])
+        state.focus(state.firstShelf + 1, 4)
+        state.key(ShellKey.Back)
+        assertEquals("A service must not overwrite the root lane", 3, state.column)
+        state.openService(snapshot.services[1])
+        state.key(ShellKey.Down)
+        assertEquals("Different services can reuse lane ids without sharing columns", 0, state.column)
+        state.key(ShellKey.Back)
+        state.openService(snapshot.services[0])
+        state.key(ShellKey.Down)
+        assertEquals(4, state.column)
+        state.enterRoute("home")
+        assertEquals("Leaving Discover clears service positions too", 0, state.column)
     }
 
     @Test

wolfskin-design/src/test/java/org/justinvisser/wolfskin/design/DiscoverNetworkHeroTest.kt

@@ -0,0 +1,91 @@
+package org.justinvisser.wolfskin.design
+
+import android.app.Application
+import android.graphics.Bitmap
+import android.graphics.BitmapFactory
+import android.view.View
+import android.view.WindowManager
+import androidx.activity.ComponentActivity
+import androidx.compose.foundation.layout.requiredSize
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.input.key.Key
+import androidx.compose.ui.test.*
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import coil3.asImage
+import coil3.decode.DataSource
+import coil3.intercept.Interceptor
+import coil3.request.SuccessResult
+import com.github.takahirom.roborazzi.captureRoboImage
+import kotlinx.coroutines.CompletableDeferred
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import org.json.JSONArray
+import org.json.JSONObject
+import org.junit.Assert.*
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.GraphicsMode
+import java.io.File
+
+/** Network-success artwork must not add Coil's independent alpha ramp beneath the hero blend. */
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [34], application = Application::class, qualifiers = "w960dp-h540dp-xhdpi")
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+class DiscoverNetworkHeroTest {
+    @get:Rule val rule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test fun delayedNetworkSuccessCannotDipThePaintedHeroOpacity() {
+        rule.activity.window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN)
+        @Suppress("DEPRECATION")
+        rule.activity.window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_FULLSCREEN or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION or View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
+        rule.mainClock.autoAdvance = false
+        val red = Bitmap.createBitmap(8, 8, Bitmap.Config.ARGB_8888).apply { eraseColor(android.graphics.Color.RED) }.asImageBitmap()
+        val blue = Bitmap.createBitmap(8, 8, Bitmap.Config.ARGB_8888).apply { eraseColor(android.graphics.Color.BLUE) }.asImage()
+        val release = CompletableDeferred<Unit>()
+        WolfskinImages.configureNetwork(rule.activity) { add(Interceptor { chain ->
+            if (chain.request.data == "network:blue") {
+                release.await()
+                SuccessResult(blue, chain.request, DataSource.NETWORK)
+            } else chain.proceed()
+        }) }
+        val fixture = discoverTestFixture()
+        val titles = fixture.snapshot("justin").picks.take(2).mapIndexed { index, title ->
+            title.copy(backdrop = if (index == 0) "network:red" else "network:blue", poster = null, posterOnly = false, score = 100.0 - index)
+        }
+        val snapshot = fixture.snapshot("justin").copy(picks = titles)
+        val shell = ShellState(fixturePeople(), "justin").apply { pickerVisible = false; enterDestination("discover") }
+        val state = DiscoverState(shell, snapshot, RecordingDiscoverOperations(snapshot, "justin"), CoroutineScope(Dispatchers.Main.immediate))
+        rule.setContent { WolfskinTheme {
+            CompositionLocalProvider(LocalDiscoverArt provides { path -> if (path == "network:red") red else null }) {
+                ShellSurface(shell, Modifier.requiredSize(WolfskinTokens.Shell.stageWidth, WolfskinTokens.Shell.stageHeight)) { DiscoverScreen(state, it) }
+            }
+        } }
+        rule.mainClock.advanceTimeBy(640)
+        rule.onNodeWithTag("wolfskin-shell").performKeyInput { keyDown(Key.DirectionRight); keyUp(Key.DirectionRight) }
+        rule.mainClock.advanceTimeBy(192)
+        rule.onNodeWithText(titles.first().title).assertIsDisplayed()
+        val directory = File(System.getProperty("wolfskin.captureDirectory"), "discover-network-hero").apply { mkdirs() }
+        val samples = JSONArray()
+        rule.runOnIdle { release.complete(Unit) }
+        var lastPixel = 0
+        repeat(40) { index ->
+            rule.mainClock.advanceTimeBy(16)
+            val file = File(directory, "network-${index.toString().padStart(2, '0')}.png")
+            rule.onRoot().captureRoboImage(file.absolutePath)
+            val bitmap = BitmapFactory.decodeFile(file.absolutePath)
+            lastPixel = try { bitmap.getPixel(1600, 200) } finally { bitmap.recycle() }
+            val redChannel = android.graphics.Color.red(lastPixel)
+            val blueChannel = android.graphics.Color.blue(lastPixel)
+            samples.put(JSONObject().put("timeMs", rule.mainClock.currentTime).put("red", redChannel).put("blue", blueChannel))
+            assertTrue("A second network-image fade exposes the dark placeholder beneath both heroes at frame $index: red=$redChannel blue=$blueChannel", redChannel + blueChannel >= 250)
+        }
+        File(directory, "series.json").writeText(samples.toString(2))
+        assertEquals(android.graphics.Color.BLUE, lastPixel)
+        rule.onNodeWithText(titles.last().title).assertIsDisplayed()
+    }
+}

wolfskin-design/src/test/java/org/justinvisser/wolfskin/design/HeroMotionTest.kt

@@ -13,6 +13,9 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.toArgb
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.test.onNodeWithText
+import androidx.compose.ui.test.assertIsDisplayed
 import androidx.compose.ui.test.junit4.createAndroidComposeRule
 import androidx.compose.ui.test.onRoot
 import androidx.compose.ui.test.onNodeWithTag
@@ -82,6 +85,35 @@ class HeroMotionTest {
         } finally { directory.deleteRecursively() }
     }
 
+    @Test fun homeHeroRetainsTheOutgoingCopyAnchorWhenTheNextTitleWraps() {
+        rule.mainClock.autoAdvance = false
+        val first = HomeTitle("first", "Short title", "movie", backdrop = "red")
+        val next = HomeTitle("next", "A much longer title that must wrap onto a second line in this hero", "movie", backdrop = "blue")
+        val selected = mutableStateOf(first)
+        val art = mapOf("red" to Color.Red, "blue" to Color.Blue).mapValues { (_, color) ->
+            android.graphics.Bitmap.createBitmap(8, 8, android.graphics.Bitmap.Config.ARGB_8888).apply { eraseColor(color.toArgb()) }.asImageBitmap()
+        }
+        rule.setContent { WolfskinTheme {
+            CompositionLocalProvider(LocalTitleBitmaps provides art) {
+                Box(Modifier.requiredSize(960.dp, 540.dp)) {
+                    HomeHero(HomeRow("hero", HomeRowKind.Hero, cards = listOf(selected.value)), true, 0, emptyList(), {}, {})
+                }
+            }
+        } }
+        rule.mainClock.advanceTimeBy(640)
+        val anchor = rule.onNodeWithText(first.title).fetchSemanticsNode().boundsInRoot
+        val actionAnchor = rule.onNodeWithText("Play").fetchSemanticsNode().boundsInRoot
+        update { selected.value = next }
+        repeat(8) {
+            rule.mainClock.advanceTimeBy(16)
+            assertEquals("A taller incoming copy cannot move the outgoing title", anchor, rule.onNodeWithText(first.title).fetchSemanticsNode().boundsInRoot)
+            assertEquals("Hero actions remain stationary outside the copy handoff", actionAnchor, rule.onNodeWithText("Play").fetchSemanticsNode().boundsInRoot)
+        }
+        rule.mainClock.advanceTimeBy(320)
+        rule.onNodeWithText(first.title).assertDoesNotExist()
+        rule.onNodeWithText(next.title).assertIsDisplayed()
+    }
+
     private fun update(block: () -> Unit) {
         rule.runOnIdle { block(); androidx.compose.runtime.snapshots.Snapshot.sendApplyNotifications() }
         rule.mainClock.advanceTimeByFrame()