From 37ad85cbaf5ee47c9e100bb026f4646ab691b8fe Mon Sep 17 00:00:00 2001
From: Omar Brikaa <brikaaomar@gmail.com>
Date: Mon, 28 Jul 2025 00:52:07 +0300
Subject: [PATCH] fix: Fix the root cause of `flushSync` flickering (#9791)

* More reliable width and height change detection

* Put the dimensions useEffect before the scene render one, just in case
---
 .../components/canvases/StaticCanvas.tsx      | 27 +++++--------------
 1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/packages/excalidraw/components/canvases/StaticCanvas.tsx b/packages/excalidraw/components/canvases/StaticCanvas.tsx
index 01ce94c431..9e23fa500b 100644
--- a/packages/excalidraw/components/canvases/StaticCanvas.tsx
+++ b/packages/excalidraw/components/canvases/StaticCanvas.tsx
@@ -34,6 +34,13 @@ const StaticCanvas = (props: StaticCanvasProps) => {
   const wrapperRef = useRef<HTMLDivElement>(null);
   const isComponentMounted = useRef(false);
 
+  useEffect(() => {
+    props.canvas.style.width = `${props.appState.width}px`;
+    props.canvas.style.height = `${props.appState.height}px`;
+    props.canvas.width = props.appState.width * props.scale;
+    props.canvas.height = props.appState.height * props.scale;
+  }, [props.appState.height, props.appState.width, props.canvas, props.scale]);
+
   useEffect(() => {
     const wrapper = wrapperRef.current;
     if (!wrapper) {
@@ -49,26 +56,6 @@ const StaticCanvas = (props: StaticCanvasProps) => {
       canvas.classList.add("excalidraw__canvas", "static");
     }
 
-    const widthString = `${props.appState.width}px`;
-    const heightString = `${props.appState.height}px`;
-    if (canvas.style.width !== widthString) {
-      canvas.style.width = widthString;
-    }
-    if (canvas.style.height !== heightString) {
-      canvas.style.height = heightString;
-    }
-
-    const scaledWidth = props.appState.width * props.scale;
-    const scaledHeight = props.appState.height * props.scale;
-    // setting width/height resets the canvas even if dimensions not changed,
-    // which would cause flicker when we skip frame (due to throttling)
-    if (canvas.width !== scaledWidth) {
-      canvas.width = scaledWidth;
-    }
-    if (canvas.height !== scaledHeight) {
-      canvas.height = scaledHeight;
-    }
-
     renderStaticScene(
       {
         canvas,