Persist per-camera live grid zoom state

web/src/utils/cameraZoom.ts

@@ -31,6 +31,24 @@ export type CameraZoomPersistedState = {
   focusY: number;
 };
 
+export function isCameraZoomPersistedState(
+  value: unknown,
+): value is CameraZoomPersistedState {
+  if (!value || typeof value !== "object") {
+    return false;
+  }
+
+  const candidate = value as Partial<CameraZoomPersistedState>;
+  return (
+    typeof candidate.normalizedScale === "number" &&
+    Number.isFinite(candidate.normalizedScale) &&
+    typeof candidate.focusX === "number" &&
+    Number.isFinite(candidate.focusX) &&
+    typeof candidate.focusY === "number" &&
+    Number.isFinite(candidate.focusY)
+  );
+}
+
 export function clamp(value: number, min: number, max: number): number {
   return Math.min(max, Math.max(min, value));
 }
@@ -160,3 +178,27 @@ export function getNextScaleFromWheelDelta(
 export function getCameraZoomStorageKey(cameraName: string): string {
   return `live:grid-card:zoom:${cameraName}`;
 }
+
+export function loadPersistedCameraZoomState(
+  cameraName: string,
+): CameraZoomPersistedState | undefined {
+  const serialized = localStorage.getItem(getCameraZoomStorageKey(cameraName));
+
+  if (!serialized) {
+    return undefined;
+  }
+
+  try {
+    const parsed = JSON.parse(serialized);
+    return isCameraZoomPersistedState(parsed) ? parsed : undefined;
+  } catch {
+    return undefined;
+  }
+}
+
+export function savePersistedCameraZoomState(
+  cameraName: string,
+  state: CameraZoomPersistedState,
+): void {
+  localStorage.setItem(getCameraZoomStorageKey(cameraName), JSON.stringify(state));
+}

web/src/views/live/DraggableGridLayout.tsx

@@ -53,8 +53,12 @@ import {
   CAMERA_ZOOM_MIN_SCALE,
   CameraZoomRuntimeTransform,
   clampScale,
+  fromPersistedCameraZoomState,
   getCursorRelativeZoomTransform,
   getNextScaleFromWheelDelta,
+  loadPersistedCameraZoomState,
+  savePersistedCameraZoomState,
+  toPersistedCameraZoomState,
 } from "@/utils/cameraZoom";
 
 type DraggableGridLayoutProps = {
@@ -434,6 +438,49 @@ export default function DraggableGridLayout({
   const [cameraZoomStates, setCameraZoomStates] = useState<
     Record<string, CameraZoomRuntimeTransform>
   >({});
+  const cameraZoomViewportRefs = useRef<Record<string, HTMLDivElement | null>>(
+    {},
+  );
+
+  const getCardZoomDimensions = useCallback((cameraName: string) => {
+    const viewport = cameraZoomViewportRefs.current[cameraName];
+    const content = viewport?.firstElementChild as HTMLElement | null;
+    const viewportWidth = viewport?.clientWidth ?? 0;
+    const viewportHeight = viewport?.clientHeight ?? 0;
+
+    return {
+      viewportWidth,
+      viewportHeight,
+      contentWidth: content?.clientWidth ?? viewportWidth,
+      contentHeight: content?.clientHeight ?? viewportHeight,
+    };
+  }, []);
+
+  const hydrateCameraZoomFromStorage = useCallback(
+    (cameraName: string) => {
+      setCameraZoomStates((prev) => {
+        if (prev[cameraName]) {
+          return prev;
+        }
+
+        const persisted = loadPersistedCameraZoomState(cameraName);
+        if (!persisted) {
+          return prev;
+        }
+
+        const dimensions = getCardZoomDimensions(cameraName);
+        if (!dimensions.viewportWidth || !dimensions.viewportHeight) {
+          return prev;
+        }
+
+        return {
+          ...prev,
+          [cameraName]: fromPersistedCameraZoomState(persisted, dimensions),
+        };
+      });
+    },
+    [getCardZoomDimensions],
+  );
 
   const getDefaultZoomTransform = useCallback(
     (): CameraZoomRuntimeTransform => ({
@@ -467,6 +514,15 @@ export default function DraggableGridLayout({
           cursorX,
           cursorY,
         );
+        const content = event.currentTarget.firstElementChild as HTMLElement | null;
+        const persisted = toPersistedCameraZoomState(next, {
+          viewportWidth: bounds.width,
+          viewportHeight: bounds.height,
+          contentWidth: content?.clientWidth ?? bounds.width,
+          contentHeight: content?.clientHeight ?? bounds.height,
+        });
+
+        savePersistedCameraZoomState(cameraName, persisted);
 
         return {
           ...prev,
@@ -477,6 +533,12 @@ export default function DraggableGridLayout({
     [getDefaultZoomTransform],
   );
 
+  useEffect(() => {
+    cameras.forEach((camera) => {
+      hydrateCameraZoomFromStorage(camera.name);
+    });
+  }, [cameras, hydrateCameraZoomFromStorage]);
+
   useEffect(() => {
     const initialStreamStatsState = getStreamStatsFromStorage();
     setGlobalStreamStatsEnabled(initialStreamStatsState);
@@ -716,6 +778,13 @@ export default function DraggableGridLayout({
                 >
                   <div
                     className="size-full overflow-hidden rounded-lg md:rounded-2xl"
+                    ref={(node) => {
+                      cameraZoomViewportRefs.current[camera.name] = node;
+
+                      if (node) {
+                        hydrateCameraZoomFromStorage(camera.name);
+                      }
+                    }}
                     onWheel={(event) => handleCardWheelZoom(camera.name, event)}
                   >
                     <div