Add PiP border in 1on1 layouts

Fixes: #4008

src/state/CallViewModel/CallViewModel.ts

@@ -155,6 +155,7 @@ import {
   createRingingMedia,
   type RingingMediaViewModel,
 } from "../media/RingingMediaViewModel.ts";
+import { type GridTileViewModel } from "../TileViewModel.ts";
 
 const logger = rootLogger.getChild("[CallViewModel]");
 //TODO
@@ -1482,6 +1483,7 @@ export function createCallViewModel$(
         ({ tiles: prevTiles }, [media, visibleTiles]) => {
           let layout: Layout;
           let newTiles: TileStore;
+          let pip: GridTileViewModel | undefined;
           switch (media.type) {
             case "grid":
             case "spotlight-landscape":
@@ -1507,6 +1509,7 @@ export function createCallViewModel$(
                 landscapePipAlignment$,
                 prevTiles,
               );
+              pip = layout.pip;
               break;
             case "one-on-one-portrait":
               [layout, newTiles] = oneOnOnePortraitLayout(
@@ -1515,12 +1518,17 @@ export function createCallViewModel$(
                 portraitPipAlignment$,
                 prevTiles,
               );
+              pip = layout.pip;
               break;
             case "pip":
               [layout, newTiles] = pipLayout(media, prevTiles);
               break;
           }
 
+          for (const tile of newTiles.gridTiles) {
+            tile.setShowOutline(tile === pip);
+          }
+
           return { layout, tiles: newTiles };
         },
         { layout: null, tiles: TileStore.empty() },

src/state/TileViewModel.ts

@@ -5,6 +5,8 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
+import { BehaviorSubject } from "rxjs";
+
 import { type Behavior } from "./Behavior";
 import { type MediaViewModel } from "./media/MediaViewModel";
 import { type RingingMediaViewModel } from "./media/RingingMediaViewModel";
@@ -17,12 +19,18 @@ function createId(): string {
 
 export class GridTileViewModel {
   public readonly id = createId();
+  private readonly _showOutline$ = new BehaviorSubject(false);
+  public readonly showOutline$: Behavior<boolean> = this._showOutline$;
 
   public constructor(
     public readonly media$: Behavior<
       UserMediaViewModel | RingingMediaViewModel
     >,
   ) {}
+
+  public setShowOutline(value: boolean): void {
+    this._showOutline$.next(value);
+  }
 }
 
 export class SpotlightTileViewModel {