fix(ui): support reliable base attachment previews (#7592)

packages/ui/src/services/gallery/__tests__/desktop-gallery.service.spec.ts

@@ -44,6 +44,17 @@ describe('DesktopGalleryService', () => {
         sub.unsubscribe();
     });
 
+    it('replays the open state when the global gallery UI subscribes after the first open', () => {
+        const service = createService();
+        service.open({ images: ['a.png'] });
+        const snapshots: IGalleryProps[] = [];
+
+        const sub = service.gallery$.subscribe((value) => snapshots.push(value));
+
+        expect(snapshots).toEqual([{ open: true, images: ['a.png'] }]);
+        sub.unsubscribe();
+    });
+
     it('completes gallery state when the open handle is disposed', () => {
         const service = createService();
         let completed = false;

packages/ui/src/services/gallery/desktop-gallery.service.ts

@@ -18,7 +18,7 @@ import type { IDisposable } from '@univerjs/core';
 import type { IGalleryProps } from '@univerjs/design';
 import type { IGalleryService } from './gallery.service';
 import { Disposable, Inject, Injector, toDisposable } from '@univerjs/core';
-import { Subject } from 'rxjs';
+import { ReplaySubject } from 'rxjs';
 import { connectInjector } from '../../utils/di';
 import { GalleryPart } from '../../views/components/gallery-part/GalleryPart';
 import { BuiltInUIPart, IUIPartsService } from '../parts/parts.service';
@@ -33,7 +33,7 @@ export class DesktopGalleryService extends Disposable implements IGalleryService
         this._initUIPart();
     }
 
-    gallery$ = new Subject<IGalleryProps>();
+    gallery$ = new ReplaySubject<IGalleryProps>(1);
 
     override dispose(): void {
         super.dispose();