Preserve poster progress and focus across library rail changes

docker/README.md

@@ -358,18 +358,28 @@ chips stay at y 252–320 and the first poster row starts at y 372 (52 px clear)
 Discover and season-chip rows retain their 104 px height.
 
 Cards and cast circles draw a single 4 px accent stroke centred on the art edge,
-above the content, with no background gap and the existing card lift. The stroke
-and art scale together at 1.08; buttons, avatars, chips and picker focus are
-unchanged. Title shelves reserve vertical drawing room for the scaled ring.
+above the content, with no background gap. Card lift parameters are unchanged;
+cast portraits and episode tiles now receive that lift too. The stroke and art
+scale together at 1.08; buttons, avatars, chips and picker focus are unchanged.
+Title shelves reserve vertical drawing room for the scaled ring.
 Before scaling the stroke, ring-to-neighbour clearances round to 28/22/16 px
 for poster/tile/wide cards; including stroke scale they are 27.6/21.8/16.1 px.
 
+Poster progress uses the independent 18 px title-card inset, not caption spacing:
+the track remains 220 px wide on a 256 px poster. Library focus-follow restarts
+when the effective column count, focused row or header geometry changes, retaining
+deep focus across live snapshots that add or remove the letter rail.
+`LibrarySpacingRegressionTest` renders both progress geometry and the unchanged
+focused index across the 199↔200-title boundary.
+
 `LibraryCaptureTest.spacingShowsFirstFocused`,
 `HomeCaptureTest.spacingNextUpFirstFocused` and
 `TitleCaptureTest.spacingCastFirstFocused` render the amended reference states
 at native resolution. Their files are `library/spacing-shows.png`,
 `home/spacing-next-up.png` and `st-114.png` under `build/wolfskin-captures/`.
-Platform Roboto metrics and fixture ordering are not browser pixel parity.
+These captures are recordings, not automated reference-pixel assertions; pair
+measurements are a separate check. Platform Roboto metrics and fixture ordering
+are not browser pixel parity.
 
 ## Title pages and people
 

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

@@ -41,8 +41,8 @@ fun LibraryPoster(
             if (title.ratings.isNotEmpty()) LibraryRatingPlate(title.ratings, visible = ratingsVisible)
             val progress = title.progress
             if (progress > 0f && progress < 1f) {
-                Box(Modifier.align(Alignment.BottomCenter).padding(horizontal = WolfskinTokens.Layout.captionOffset, vertical = WolfskinTokens.Layout.navItemGap)
-                    .fillMaxWidth().height(WolfskinTokens.Layout.progressBar).background(C.progressTrack, CircleShape)) {
+                Box(Modifier.align(Alignment.BottomCenter).padding(horizontal = WolfskinTokens.Title.cardProgressInset, vertical = WolfskinTokens.Layout.navItemGap)
+                    .fillMaxWidth().height(WolfskinTokens.Layout.progressBar).testTag("poster-progress-${title.id}").background(C.progressTrack, CircleShape)) {
                     Box(Modifier.fillMaxHeight().fillMaxWidth(progress).background(C.accent, CircleShape))
                 }
             }

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

@@ -88,13 +88,13 @@ fun LibraryScreen(
     }
     val headerCount = if (grid.hasToolbar && grid.status != LibraryStatus.Loading && grid.status != LibraryStatus.Unavailable) 2 else 1
     val rowHeight = K.posterH + K.posterCaptionBand + L.gridRowGap
-    LaunchedEffect(grid.index, grid.toolbar, grid.inRail, grid.railLetter, shell.navFocused, view) {
-        val index = if (grid.inRail) items.indexOfFirst { it.letter == grid.railLetter } else grid.index
-        val row = index.coerceAtLeast(0) / grid.columns
-        if (grid.toolbar || row == 0 && active) {
+    val focusedRow = (if (grid.inRail) items.indexOfFirst { it.letter == grid.railLetter } else grid.index).coerceAtLeast(0) / grid.columns
+    LaunchedEffect(grid.index, grid.columns, focusedRow, headerCount, rowHeight, density,
+        grid.toolbar, grid.inRail, grid.railLetter, shell.navFocused, view) {
+        if (grid.toolbar || focusedRow == 0 && active) {
             animateLibraryScroll(view, headerCount, 0f, density)
-        } else if (row > 0) {
-            val target = with(density) { (L.row_lhead + (if (headerCount == 2) L.row_chipsGrid else WolfskinTokens.Shell.zero) + rowHeight * row - L.pinnedLine).toPx() }
+        } else if (focusedRow > 0) {
+            val target = with(density) { (L.row_lhead + (if (headerCount == 2) L.row_chipsGrid else WolfskinTokens.Shell.zero) + rowHeight * focusedRow - L.pinnedLine).toPx() }
             animateLibraryScroll(view, headerCount, target, density)
         }
     }

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

@@ -0,0 +1,53 @@
+package org.justinvisser.wolfskin.design
+
+import android.app.Application
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.test.onNodeWithTag
+import org.junit.Assert.assertEquals
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+/** Caption spacing and live rail changes must preserve poster geometry and retained focus. */
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [34], application = Application::class, qualifiers = "w960dp-h540dp-xhdpi")
+class LibrarySpacingRegressionTest {
+    @get:Rule val rule = createComposeRule()
+
+    @Test fun partiallyWatchedPosterKeepsItsOriginalProgressInsets() {
+        val title = LibraryTitle("partial", "Partially watched", "movie", progress = .5f)
+        rule.setContent { WolfskinTheme { LibraryPoster(title, false, false, false) } }
+        val poster = rule.onNodeWithTag("poster-partial").fetchSemanticsNode().boundsInRoot
+        val track = rule.onNodeWithTag("poster-progress-partial").fetchSemanticsNode().boundsInRoot
+        assertEquals(256f, poster.width, .1f)
+        assertEquals(220f, track.width, .1f)
+        assertEquals(18f, track.left - poster.left, .1f)
+        assertEquals(18f, poster.right - track.right, .1f)
+    }
+
+    @Test fun crossingRailThresholdKeepsTheSameDeepFocusedPosterVisible() {
+        val titles = List(200) { LibraryTitle("$it", "Title ${it.toString().padStart(3, '0')}", "tv") }
+        val shell = ShellState(fixturePeople(), "justin").apply { pickerVisible = false; enterDestination("shows") }
+        val grid = LibraryGridState("Shows", titles.take(199)).apply { index = 198 }
+        rule.setContent { WolfskinTheme { ShellSurface(shell) { LibraryScreen(shell, grid, it) } } }
+        rule.mainClock.advanceTimeBy(1000)
+        rule.waitForIdle()
+        val poster = rule.onNodeWithTag("poster-198")
+        poster.assertIsDisplayed()
+        val original = poster.fetchSemanticsNode().boundsInRoot
+        for (count in listOf(200, 199)) {
+            rule.runOnIdle { grid.source = titles.take(count) }
+            rule.mainClock.advanceTimeBy(1000)
+            rule.waitForIdle()
+            poster.assertIsDisplayed()
+            val current = poster.fetchSemanticsNode().boundsInRoot
+            assertEquals(198, grid.index)
+            assertEquals("198", grid.focusedTitle!!.id)
+            assertEquals(original.top, current.top, 1f)
+            assertEquals(original.height, current.height, 1f)
+        }
+    }
+}