Implement the new spotlight layout

src/grid/CallLayout.ts

@@ -0,0 +1,55 @@
+/*
+Copyright 2024 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { BehaviorSubject, Observable } from "rxjs";
+
+import { MediaViewModel } from "../state/MediaViewModel";
+import { LayoutSystem } from "./Grid";
+import { Alignment } from "../room/InCallView";
+
+export interface Bounds {
+  width: number;
+  height: number;
+}
+
+export interface CallLayoutInputs {
+  /**
+   * The minimum bounds of the layout area.
+   */
+  minBounds: Observable<Bounds>;
+  /**
+   * The alignment of the floating tile, if any.
+   */
+  floatingAlignment: BehaviorSubject<Alignment>;
+}
+
+export interface CallLayoutOutputs<Model> {
+  /**
+   * The visually fixed (non-scrolling) layer of the layout.
+   */
+  fixed: LayoutSystem<Model, MediaViewModel[], HTMLDivElement>;
+  /**
+   * The layer of the layout that can overflow and be scrolled.
+   */
+  scrolling: LayoutSystem<Model, MediaViewModel, HTMLDivElement>;
+}
+
+/**
+ * A layout system for media tiles.
+ */
+export type CallLayout<Model> = (
+  inputs: CallLayoutInputs,
+) => CallLayoutOutputs<Model>;

src/grid/GridLayout.tsx

@@ -15,41 +15,30 @@ limitations under the License.
 */
 
 import { CSSProperties, forwardRef, useMemo } from "react";
-import { BehaviorSubject, Observable, distinctUntilChanged } from "rxjs";
+import { distinctUntilChanged } from "rxjs";
 import { useObservableEagerState } from "observable-hooks";
 
 import { GridLayout as GridLayoutModel } from "../state/CallViewModel";
-import { MediaViewModel } from "../state/MediaViewModel";
-import { LayoutSystem, Slot } from "./Grid";
+import { Slot } from "./Grid";
 import styles from "./GridLayout.module.css";
 import { useReactiveState } from "../useReactiveState";
-import { Alignment } from "../room/InCallView";
 import { useInitial } from "../useInitial";
-
-export interface Bounds {
-  width: number;
-  height: number;
-}
+import { CallLayout } from "./CallLayout";
 
 interface GridCSSProperties extends CSSProperties {
   "--gap": string;
   "--width": string;
   "--height": string;
 }
 
-interface GridLayoutSystems {
-  scrolling: LayoutSystem<GridLayoutModel, MediaViewModel, HTMLDivElement>;
-  fixed: LayoutSystem<GridLayoutModel, MediaViewModel[], HTMLDivElement>;
-}
-
 const slotMinHeight = 130;
 const slotMaxAspectRatio = 17 / 9;
 const slotMinAspectRatio = 4 / 3;
 
-export const gridLayoutSystems = (
-  minBounds: Observable<Bounds>,
-  floatingAlignment: BehaviorSubject<Alignment>,
-): GridLayoutSystems => ({
+export const makeGridLayout: CallLayout<GridLayoutModel> = ({
+  minBounds,
+  floatingAlignment,
+}) => ({
   // The "fixed" (non-scrolling) part of the layout is where the spotlight tile
   // lives
   fixed: {

src/grid/SpotlightLayout.module.css

@@ -0,0 +1,63 @@
+/*
+Copyright 2024 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+.fixed,
+.scrolling {
+  display: grid;
+  --grid-slot-width: 180px;
+  --grid-gap: 20px;
+  grid-template-columns: 1fr calc(
+      var(--grid-columns) * var(--grid-slot-width) + (var(--grid-columns) - 1) *
+        var(--grid-gap)
+    );
+  grid-template-rows: minmax(1fr, auto);
+  grid-template-areas: "spotlight grid";
+  gap: 30px;
+}
+
+.scrolling {
+  block-size: 100%;
+}
+
+.spotlight {
+  grid-area: spotlight;
+  container: spotlight / size;
+  display: grid;
+  place-items: center;
+}
+
+/* CSS makes us put a condition here, even though all we want to do is
+unconditionally select the container so we can use cq units */
+@container spotlight (width > 0) {
+  .spotlight > .slot {
+    inline-size: min(100cqi, 100cqb * (17 / 9));
+    block-size: min(100cqb, 100cqi / (4 / 3));
+  }
+}
+
+.grid {
+  grid-area: grid;
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--grid-gap);
+  justify-content: center;
+  align-content: center;
+}
+
+.grid > .slot {
+  inline-size: var(--grid-slot-width);
+  block-size: 135px;
+}

src/grid/SpotlightLayout.tsx

@@ -0,0 +1,87 @@
+/*
+Copyright 2024 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { CSSProperties, forwardRef } from "react";
+import { useObservableEagerState } from "observable-hooks";
+
+import { CallLayout } from "./CallLayout";
+import { SpotlightLayout as SpotlightLayoutModel } from "../state/CallViewModel";
+import { useReactiveState } from "../useReactiveState";
+import styles from "./SpotlightLayout.module.css";
+import { Slot } from "./Grid";
+
+interface GridCSSProperties extends CSSProperties {
+  "--grid-columns": number;
+}
+
+const getGridColumns = (gridLength: number): number =>
+  gridLength > 20 ? 2 : 1;
+
+export const makeSpotlightLayout: CallLayout<SpotlightLayoutModel> = ({
+  minBounds,
+}) => ({
+  fixed: {
+    tiles: (model) => new Map([["spotlight", model.spotlight]]),
+    Layout: forwardRef(function SpotlightLayoutFixed({ model }, ref) {
+      const { width, height } = useObservableEagerState(minBounds);
+      const gridColumns = getGridColumns(model.grid.length);
+      const [generation] = useReactiveState<number>(
+        (prev) => (prev === undefined ? 0 : prev + 1),
+        [model.grid.length, width, height],
+      );
+
+      return (
+        <div
+          ref={ref}
+          className={styles.fixed}
+          data-generation={generation}
+          style={{ "--grid-columns": gridColumns, height } as GridCSSProperties}
+        >
+          <div className={styles.spotlight}>
+            <Slot className={styles.slot} tile="spotlight" />
+          </div>
+        </div>
+      );
+    }),
+  },
+
+  scrolling: {
+    tiles: (model) => new Map(model.grid.map((tile) => [tile.id, tile])),
+    Layout: forwardRef(function SpotlightLayoutScrolling({ model }, ref) {
+      const { width, height } = useObservableEagerState(minBounds);
+      const gridColumns = getGridColumns(model.grid.length);
+      const [generation] = useReactiveState<number>(
+        (prev) => (prev === undefined ? 0 : prev + 1),
+        [model.grid, width, height],
+      );
+
+      return (
+        <div
+          ref={ref}
+          data-generation={generation}
+          className={styles.scrolling}
+          style={{ "--grid-columns": gridColumns } as GridCSSProperties}
+        >
+          <div className={styles.grid}>
+            {model.grid.map((tile) => (
+              <Slot className={styles.slot} tile={tile.id} />
+            ))}
+          </div>
+        </div>
+      );
+    }),
+  },
+});

src/room/InCallView.tsx

@@ -35,7 +35,7 @@ import {
 import useMeasure from "react-use-measure";
 import { MatrixRTCSession } from "matrix-js-sdk/src/matrixrtc/MatrixRTCSession";
 import classNames from "classnames";
-import { BehaviorSubject } from "rxjs";
+import { BehaviorSubject, map } from "rxjs";
 import { useObservableEagerState } from "observable-hooks";
 import { useTranslation } from "react-i18next";
 
@@ -73,17 +73,20 @@ import { ECConnectionState } from "../livekit/useECConnectionState";
 import { useOpenIDSFU } from "../livekit/openIDSFU";
 import {
   GridMode,
+  Layout,
   TileDescriptor,
   useCallViewModel,
 } from "../state/CallViewModel";
 import { Grid, TileProps } from "../grid/Grid";
 import { MediaViewModel } from "../state/MediaViewModel";
-import { gridLayoutSystems } from "../grid/GridLayout";
 import { useObservable } from "../state/useObservable";
 import { useInitial } from "../useInitial";
 import { SpotlightTile } from "../tile/SpotlightTile";
 import { EncryptionSystem } from "../e2ee/sharedKeyManagement";
 import { E2eeType } from "../e2ee/e2eeType";
+import { makeGridLayout } from "../grid/GridLayout";
+import { makeSpotlightLayout } from "../grid/SpotlightLayout";
+import { CallLayout } from "../grid/CallLayout";
 
 const canScreenshare = "getDisplayMedia" in (navigator.mediaDevices ?? {});
 
@@ -302,6 +305,7 @@ export const InCallView: FC<InCallViewProps> = ({
 
   const [headerRef, headerBounds] = useMeasure();
   const [footerRef, footerBounds] = useMeasure();
+
   const gridBounds = useMemo(
     () => ({
       width: footerBounds.width,
@@ -315,11 +319,29 @@ export const InCallView: FC<InCallViewProps> = ({
     ],
   );
   const gridBoundsObservable = useObservable(gridBounds);
+
   const floatingAlignment = useInitial(
     () => new BehaviorSubject(defaultAlignment),
   );
-  const { fixed, scrolling } = useInitial(() =>
-    gridLayoutSystems(gridBoundsObservable, floatingAlignment),
+
+  const layoutSystem = useObservableEagerState(
+    useInitial(() =>
+      vm.layout.pipe(
+        map((l) => {
+          let makeLayout: CallLayout<Layout>;
+          if (l.type === "grid" && l.grid.length !== 2)
+            makeLayout = makeGridLayout as CallLayout<Layout>;
+          else if (l.type === "spotlight")
+            makeLayout = makeSpotlightLayout as CallLayout<Layout>;
+          else return null; // Not yet implemented
+
+          return makeLayout({
+            minBounds: gridBoundsObservable,
+            floatingAlignment,
+          });
+        }),
+      ),
+    ),
   );
 
   const setGridMode = useCallback(
@@ -423,39 +445,35 @@ export const InCallView: FC<InCallViewProps> = ({
       );
     }
 
-    // The only new layout we've implemented so far is grid layout for non-1:1
-    // calls. All other layouts use the legacy grid system for now.
-    if (
-      legacyLayout === "grid" &&
-      layout.type === "grid" &&
-      !(layout.grid.length === 2 && layout.spotlight === undefined)
-    ) {
+    if (layoutSystem === null) {
+      // This new layout doesn't yet have an implemented layout system, so fall
+      // back to the legacy grid system
+      return (
+        <LegacyGrid
+          items={items}
+          layout={legacyLayout}
+          disableAnimations={prefersReducedMotion}
+          Tile={GridTileView}
+        />
+      );
+    } else {
       return (
         <>
           <Grid
             className={styles.scrollingGrid}
             model={layout}
-            system={scrolling}
+            system={layoutSystem.scrolling}
             Tile={GridTileView}
           />
           <Grid
             className={styles.fixedGrid}
             style={{ insetBlockStart: headerBounds.bottom }}
             model={layout}
-            system={fixed}
+            system={layoutSystem.fixed}
             Tile={SpotlightTileView}
           />
         </>
       );
-    } else {
-      return (
-        <LegacyGrid
-          items={items}
-          layout={legacyLayout}
-          disableAnimations={prefersReducedMotion}
-          Tile={GridTileView}
-        />
-      );
     }
   };