feat: Visual debugger (#8344)

Add visual debugger to the Excalidraw app (only).

excalidraw-app/App.tsx

@@ -120,6 +120,11 @@ import {
 import { appThemeAtom, useHandleAppTheme } from "./useHandleAppTheme";
 import { getPreferredLanguage } from "./app-language/language-detector";
 import { useAppLangCode } from "./app-language/language-state";
+import DebugCanvas, {
+  debugRenderer,
+  isVisualDebuggerEnabled,
+  loadSavedDebugState,
+} from "./components/DebugCanvas";
 import { AIComponents } from "./components/AI";
 
 polyfill();
@@ -337,6 +342,8 @@ const ExcalidrawWrapper = () => {
       resolvablePromise<ExcalidrawInitialDataState | null>();
   }
 
+  const debugCanvasRef = useRef<HTMLCanvasElement>(null);
+
   useEffect(() => {
     trackEvent("load", "frame", getFrame());
     // Delayed so that the app has a time to load the latest SW
@@ -362,6 +369,23 @@ const ExcalidrawWrapper = () => {
     migrationAdapter: LibraryLocalStorageMigrationAdapter,
   });
 
+  const [, forceRefresh] = useState(false);
+
+  useEffect(() => {
+    if (import.meta.env.DEV) {
+      const debugState = loadSavedDebugState();
+
+      if (debugState.enabled && !window.visualDebug) {
+        window.visualDebug = {
+          data: [],
+        };
+      } else {
+        delete window.visualDebug;
+      }
+      forceRefresh((prev) => !prev);
+    }
+  }, [excalidrawAPI]);
+
   useEffect(() => {
     if (!excalidrawAPI || (!isCollabDisabled && !collabAPI)) {
       return;
@@ -622,6 +646,11 @@ const ExcalidrawWrapper = () => {
         }
       });
     }
+
+    // Render the debug scene if the debug canvas is available
+    if (debugCanvasRef.current && excalidrawAPI) {
+      debugRenderer(debugCanvasRef.current, appState, window.devicePixelRatio);
+    }
   };
 
   const [latestShareableLink, setLatestShareableLink] = useState<string | null>(
@@ -820,6 +849,7 @@ const ExcalidrawWrapper = () => {
           isCollabEnabled={!isCollabDisabled}
           theme={appTheme}
           setTheme={(theme) => setAppTheme(theme)}
+          refresh={() => forceRefresh((prev) => !prev)}
         />
         <AppWelcomeScreen
           onCollabDialogOpen={onCollabDialogOpen}
@@ -845,7 +875,7 @@ const ExcalidrawWrapper = () => {
             </OverwriteConfirmDialog.Action>
           )}
         </OverwriteConfirmDialog>
-        <AppFooter />
+        <AppFooter onChange={() => excalidrawAPI?.refresh()} />
         {excalidrawAPI && <AIComponents excalidrawAPI={excalidrawAPI} />}
 
         <TTDDialogTrigger />
@@ -1077,6 +1107,13 @@ const ExcalidrawWrapper = () => {
             },
           ]}
         />
+        {isVisualDebuggerEnabled() && excalidrawAPI && (
+          <DebugCanvas
+            appState={excalidrawAPI.getAppState()}
+            scale={window.devicePixelRatio}
+            ref={debugCanvasRef}
+          />
+        )}
       </Excalidraw>
     </div>
   );