src/app/call.ts

@@ -31,93 +31,290 @@ export const LIVEKIT_PARTICIPANTS = 39004
 
 export {supportsAudioOutputSelection}
 
-/** Aspect ratio constraints — tiles can flex between 3:4 (portrait) and 16:9 (landscape). */
-const TILE_ASPECT_MIN = 3 / 4
-const TILE_ASPECT_MAX = 16 / 9
+/**
+ * Aspect ratio constraints — tiles can flex between 3:4 (portrait)
+ * and 16:9 (landscape). Tiles are ALLOWED to be wider than 16:9
+ * when the container is very wide, to prevent overflow (review #2
+ * bug: n=2 second tile half off screen). The lower bound (3:4)
+ * prevents tiles from being too tall.
+ */
+const TILE_ASPECT_PORTRAIT = 3 / 4
+const TILE_ASPECT_LANDSCAPE = 16 / 9
 const TILE_GAP = 8
 
 /**
- * Uniform-size tile grid: all tiles are identical px dimensions, arranged
- * in a CSS grid. Column count is chosen to maximize tile area while
- * respecting aspect ratio bounds [3:4 .. 16:9].
- * Orphan rows (fewer tiles than a full row) center at the same tile size.
+ * Minimum pixel height for a tile before we allow the grid to
+ * overflow (scroll) instead of forcing tiles into portrait mode.
+ * Calibrated so ~6-8 tiles on a standard portrait phone fit
+ * without scrolling; beyond that, scroll is acceptable.
  */
-export type UniformTileGrid = {
-  cols: number
-  rows: number
+const MIN_TILE_HEIGHT = 120
+
+/**
+ * A single row in an adaptive tile grid: tiles in this row share
+ * the same dimensions but may differ from other rows.
+ */
+export type TileRow = {
+  columnCount: number
   tileWidth: number
   tileHeight: number
-  aspect: number
+  aspectRatio: number
 }
 
 /**
-/** Numeric lexicographic comparison for scoring arrays. */
-const compareKeys = (a: number[], b: number[]): number => {
-  for (let i = 0; i < a.length; i++) {
-    if (a[i] !== b[i]) return a[i] - b[i]
+ * Adaptive tile grid: rows can have different tile sizes, allowing
+ * a Jitsi-style layout where tiles flex between 3:4 and 16:9 and
+ * partial rows use wider tiles to fill whitespace.
+ *
+ * Example (3 tiles, 2 columns):
+ *   row 0: [ square ] [ square ]
+ *   row 1: [   16:9     ]   (centered)
+ */
+export type AdaptiveTileGrid = {
+  rows: TileRow[]
+  totalWidth: number
+  totalHeight: number
+  /** True when the grid overflows — tiles are below MIN_TILE_HEIGHT */
+  overflows: boolean
+}
+
+/**
+ * Score for comparing candidate layouts. Lower is better.
+ * Uses named fields instead of opaque array "keys" (per review feedback).
+ */
+type LayoutScore = {
+  /** Penalty for vertical overflow: 0 if none, else huge */
+  verticalOverflowPenalty: number
+  /** Penalty for horizontal overflow: 0 if none, else huge */
+  horizontalOverflowPenalty: number
+  /** Penalty when tiles fall below MIN_TILE_HEIGHT even while fitting */
+  minTileHeightPenalty: number
+  /** Negative tile area (we want to maximize area, so negate) */
+  negativeArea: number
+  /** Leftover whitespace (underflow) in px */
+  whitespace: number
+  /** Average absolute deviation from 16:9 across all tiles */
+  aspectDeviation: number
+}
+
+const compareScores = (a: LayoutScore, b: LayoutScore): number => {
+  const fields: (keyof LayoutScore)[] = [
+    "verticalOverflowPenalty",
+    "horizontalOverflowPenalty",
+    "minTileHeightPenalty",
+    "negativeArea",
+    "whitespace",
+    "aspectDeviation",
+  ]
+  for (const field of fields) {
+    if (a[field] !== b[field]) return a[field] - b[field]
   }
   return 0
 }
 
 /**
- * Pick the column count that best fills the viewport. Prioritises:
- *  1. No vertical overflow (avoids unnecessary scroll)
- *  2. No horizontal overflow (avoids sideways clip/scroll)
- *  3. Minimal leftover whitespace (h-pad + v-pad)
- *  4. Aspect ratio closest to 16:9
- *  5. Larger tiles
+ * Build a single-row TileRow for the uniform case where all rows
+ * have the same number of tiles. No upper-bound clamping on aspect
+ * ratio — tiles can be wider than 16:9 to avoid overflow.
  */
-export const computeUniformGrid = (
+const buildUniformRow = (
+  columnCount: number,
+  containerWidth: number,
+  containerHeight: number,
+  rowCount: number,
+): TileRow => {
+  const gap = TILE_GAP
+  const availableHeight = containerHeight - (rowCount - 1) * gap
+  const rowHeight = availableHeight / rowCount
+  const tileWidth = (containerWidth - (columnCount - 1) * gap) / columnCount
+  const fillAspect = tileWidth / rowHeight
+  // Cap at 16:9 to avoid horizontally stretching video (review feedback)
+  const aspectRatio = Math.max(TILE_ASPECT_PORTRAIT, Math.min(TILE_ASPECT_LANDSCAPE, fillAspect))
+  const tileHeight = tileWidth / aspectRatio
+  return {columnCount, tileWidth, tileHeight, aspectRatio}
+}
+
+/**
+ * Build a mixed-size layout candidate for a given column count.
+ * Uses a "match heights" approach: the last (partial) row is at 16:9
+ * (per review #1: "single centered 16:9 tile") and full-row tiles
+ * match that same height. This creates a cohesive Jitsi-style look
+ * where all tiles in all rows are the same height, with different
+ * widths per row (full-row tiles are narrower/squarer, last-row
+ * tiles are wider).
+ *
+ * If the full-row aspect would go below the portrait bound (3:4),
+ * the height diverges: full rows clamp to 3:4 portrait.
+ */
+const buildMixedCandidate = (
   tileCount: number,
-  cw: number,
-  ch: number,
-): UniformTileGrid | undefined => {
-  if (tileCount <= 0 || cw <= 0 || ch <= 0) return undefined
+  columnCount: number,
+  containerWidth: number,
+  containerHeight: number,
+): AdaptiveTileGrid | undefined => {
+  const gap = TILE_GAP
+  const fullRowCount = Math.floor(tileCount / columnCount)
+  const remainder = tileCount % columnCount
+  const totalRowCount = fullRowCount + 1
 
-  let best: UniformTileGrid | undefined
-  let bestKey: number[] | undefined
+  const tileWidthFull = (containerWidth - (columnCount - 1) * gap) / columnCount
+  if (tileWidthFull <= 0) return undefined
 
-  for (let cols = 1; cols <= tileCount; cols++) {
-    const rows = Math.ceil(tileCount / cols)
-    const availH = ch - (rows - 1) * TILE_GAP
-    const widthLimit = (cw - (cols - 1) * TILE_GAP) / cols
-    if (availH <= 0 || widthLimit <= 0) continue
+  const tileWidthLast = (containerWidth - (remainder - 1) * gap) / remainder
+  if (tileWidthLast <= 0) return undefined
 
-    const rowH = availH / rows
-    const fillAspect = widthLimit / rowH
-    const aspect = Math.max(TILE_ASPECT_MIN, Math.min(TILE_ASPECT_MAX, fillAspect))
+  // Find a common height that fits both row types and container
+  const maxPossibleHeight = Math.min(
+    tileWidthFull / TILE_ASPECT_PORTRAIT,
+    tileWidthLast / TILE_ASPECT_PORTRAIT,
+    (containerHeight - (totalRowCount - 1) * gap) / totalRowCount,
+  )
 
-    let tileW: number, tileH: number
-    if (fillAspect > TILE_ASPECT_MAX) {
-      // Too wide: cap at 16:9, tiles taller than row -> vertical overflow
-      tileW = widthLimit
-      tileH = widthLimit / TILE_ASPECT_MAX
-    } else if (fillAspect < TILE_ASPECT_MIN) {
-      // Too tall: cap at 3:4, tiles shorter than row -> v-pad (letterbox)
-      tileW = widthLimit
-      tileH = widthLimit / TILE_ASPECT_MIN
+  // Target 16:9 for the last row if possible
+  const targetHeight = tileWidthLast / TILE_ASPECT_LANDSCAPE
+  const commonHeight = Math.min(maxPossibleHeight, targetHeight)
+
+  const tileHeightFull = commonHeight
+  const tileHeightLast = commonHeight
+  const fullRowAspectRatio = tileWidthFull / commonHeight
+  const lastRowAspectRatio = tileWidthLast / commonHeight
+
+  const totalHeight = fullRowCount * tileHeightFull + tileHeightLast + (totalRowCount - 1) * gap
+  const totalWidth = Math.max(
+    columnCount * tileWidthFull + (columnCount - 1) * gap,
+    remainder * tileWidthLast + (remainder - 1) * gap,
+  )
+
+  const rows: TileRow[] = []
+  for (let r = 0; r < fullRowCount; r++) {
+    rows.push({
+      columnCount,
+      tileWidth: tileWidthFull,
+      tileHeight: tileHeightFull,
+      aspectRatio: fullRowAspectRatio,
+    })
+  }
+  rows.push({
+    columnCount: remainder,
+    tileWidth: tileWidthLast,
+    tileHeight: tileHeightLast,
+    aspectRatio: lastRowAspectRatio,
+  })
+
+  return {
+    rows,
+    totalWidth,
+    totalHeight,
+    overflows: totalHeight > containerHeight,
+  }
+}
+
+/**
+ * Compute an adaptive tile grid using Jitsi-style mixed row sizes.
+ *
+ * - Tiles flex between 3:4 (portrait) and wider than 16:9 if needed
+ *   to avoid overflow. No upper bound on aspect ratio — tiles can
+ *   be wider than 16:9 when the container is very wide.
+ * - When the last row is partial (fewer tiles than a full row),
+ *   those tiles are wider (16:9) while full rows use square-ish
+ *   tiles, filling whitespace per review #1.
+ * - Only allows overflow (scroll) when tiles would be below
+ *   MIN_TILE_HEIGHT (review #2: ~6-8 tiles on portrait phone).
+ *
+ * Prioritises:
+ *  1. No overflow (tiles shrink to fit within aspect bounds)
+ *  2. Minimal whitespace
+ *  3. Aspect ratios close to 16:9
+ *  4. Larger tiles
+ */
+export const computeAdaptiveGrid = (
+  tileCount: number,
+  containerWidth: number,
+  containerHeight: number,
+): AdaptiveTileGrid | undefined => {
+  if (tileCount <= 0 || containerWidth <= 0 || containerHeight <= 0) return undefined
+
+  let best: AdaptiveTileGrid | undefined
+  let bestScore: LayoutScore | undefined
+
+  for (let columnCount = 1; columnCount <= tileCount; columnCount++) {
+    const fullRowCount = Math.floor(tileCount / columnCount)
+    const remainder = tileCount % columnCount
+    const totalRowCount = fullRowCount + (remainder > 0 ? 1 : 0)
+
+    let candidate: AdaptiveTileGrid | undefined
+
+    if (remainder === 0) {
+      // Uniform layout — all rows identical
+      const row = buildUniformRow(columnCount, containerWidth, containerHeight, totalRowCount)
+      const totalHeight = totalRowCount * row.tileHeight + (totalRowCount - 1) * TILE_GAP
+      const totalWidth = columnCount * row.tileWidth + (columnCount - 1) * TILE_GAP
+      const rows: TileRow[] = []
+      for (let r = 0; r < totalRowCount; r++) {
+        rows.push({...row})
+      }
+      candidate = {
+        rows,
+        totalWidth,
+        totalHeight,
+        overflows: totalHeight > containerHeight,
+      }
     } else {
-      // In range: fills both dims exactly
-      tileW = widthLimit
-      tileH = rowH
+      // Mixed layout — last row has fewer tiles, make them wider
+      candidate = buildMixedCandidate(tileCount, columnCount, containerWidth, containerHeight)
     }
 
-    const bboxW = cols * tileW + (cols - 1) * TILE_GAP
-    const bboxH = rows * tileH + (rows - 1) * TILE_GAP
-    const vOverflow = Math.max(0, bboxH - ch)
-    const hOverflow = Math.max(0, bboxW - cw)
-    const waste = Math.max(0, cw - bboxW) + Math.max(0, ch - bboxH)
-    const key = [
-      Math.round(vOverflow),
-      Math.round(hOverflow),
-      Math.round(waste),
-      Number(Math.abs(aspect - TILE_ASPECT_MAX).toFixed(3)),
-      -Math.round(tileW * tileH),
-    ]
+    if (!candidate) continue
 
-    if (!bestKey || compareKeys(key, bestKey) < 0) {
-      bestKey = key
-      best = {cols, rows, tileWidth: tileW, tileHeight: tileH, aspect}
+    // Compute score
+    const verticalOverflow = Math.max(0, candidate.totalHeight - containerHeight)
+    const horizontalOverflow = Math.max(0, candidate.totalWidth - containerWidth)
+    const whitespace =
+      Math.max(0, containerWidth - candidate.totalWidth) +
+      Math.max(0, containerHeight - candidate.totalHeight)
+    const aspectDeviation =
+      candidate.rows.reduce(
+        (sum, row) => sum + Math.abs(row.aspectRatio - TILE_ASPECT_LANDSCAPE),
+        0,
+      ) / candidate.rows.length
+    const totalArea = candidate.rows.reduce(
+      (sum, row) => sum + row.tileWidth * row.tileHeight * row.columnCount,
+      0,
+    )
+
+    // For overflow: if tiles are above MIN_TILE_HEIGHT, overflow is
+    // unacceptable — heavily penalize. If tiles are below MIN_TILE_HEIGHT,
+    // overflow is acceptable (tiles are already too small to shrink further).
+    const minTileHeightInCandidate = Math.min(...candidate.rows.map(r => r.tileHeight))
+    const verticalOverflowPenalty =
+      verticalOverflow > 0 && minTileHeightInCandidate >= MIN_TILE_HEIGHT
+        ? verticalOverflow * 1_000_000
+        : verticalOverflow
+
+    const horizontalOverflowPenalty =
+      horizontalOverflow > 0 && minTileHeightInCandidate >= MIN_TILE_HEIGHT
+        ? horizontalOverflow * 1_000_000
+        : horizontalOverflow
+
+    // Min-tile-height penalty: even when fitting, discourage layouts
+    // where tiles are below the minimum acceptable size.
+    const minTileHeightPenalty =
+      minTileHeightInCandidate < MIN_TILE_HEIGHT
+        ? (MIN_TILE_HEIGHT - minTileHeightInCandidate) * 1000
+        : 0
+
+    const score: LayoutScore = {
+      verticalOverflowPenalty,
+      horizontalOverflowPenalty,
+      minTileHeightPenalty,
+      negativeArea: -totalArea,
+      whitespace,
+      aspectDeviation,
+    }
+
+    if (!bestScore || compareScores(score, bestScore) < 0) {
+      bestScore = score
+      best = candidate
     }
   }
 

src/app/components/VideoCallContent.svelte

@@ -19,8 +19,8 @@
     participantMediaState,
     pubkeyFromLiveKitIdentity,
     videoTrackRevision,
-    computeUniformGrid,
-    type UniformTileGrid,
+    computeAdaptiveGrid,
+    type AdaptiveTileGrid,
   } from "@app/call"
   import {profiles} from "@app/core"
 
@@ -157,8 +157,8 @@
   const useSpotlightLayout = $derived(primaryTile !== undefined)
   const useMultiGrid = $derived(!useSpotlightLayout)
 
-  const tileGrid = $derived<UniformTileGrid | undefined>(
-    useMultiGrid ? computeUniformGrid(videoTiles.length, gridWidth, gridHeight) : undefined,
+  const tileGrid = $derived<AdaptiveTileGrid | undefined>(
+    useMultiGrid ? computeAdaptiveGrid(videoTiles.length, gridWidth, gridHeight) : undefined,
   )
 
   $effect(() => {
@@ -272,14 +272,21 @@
         bind:clientHeight={gridHeight}
         class="min-h-0 flex-1 overflow-y-auto">
         {#if tileGrid}
-          <div
-            class="mx-auto flex flex-wrap justify-center gap-2"
-            style={`max-width: ${tileGrid.cols * tileGrid.tileWidth + (tileGrid.cols - 1) * 8}px`}>
-            {#each videoTiles as tile (tileKey(tile))}
+          <div class="flex flex-col items-center gap-2">
+            {#each tileGrid.rows as row, rowIndex}
+              {@const offset = tileGrid.rows
+                .slice(0, rowIndex)
+                .reduce((sum, r) => sum + r.columnCount, 0)}
               <div
-                class="overflow-hidden rounded-2xl shrink-0"
-                style={`width: ${tileGrid.tileWidth}px; height: ${tileGrid.tileHeight}px`}>
-                {@render videoTile(tile, "default")}
+                class="flex flex-wrap justify-center gap-2"
+                style={`max-width: ${row.columnCount * row.tileWidth + (row.columnCount - 1) * 8}px`}>
+                {#each videoTiles.slice(offset, offset + row.columnCount) as tile (tileKey(tile))}
+                  <div
+                    class="overflow-hidden rounded-2xl shrink-0"
+                    style={`width: ${row.tileWidth}px; height: ${row.tileHeight}px`}>
+                    {@render videoTile(tile, "default")}
+                  </div>
+                {/each}
               </div>
             {/each}
           </div>