From 026164f86d6bb2d507a986d064abbcc00d63be58 Mon Sep 17 00:00:00 2001
From: 134 <a134@134deMacBook-Pro.local>
Date: Fri, 3 Jul 2026 22:07:46 +0800
Subject: [PATCH] fix: ignore top background sheets in scale masks

---
 app/api/canvas/local-edit/route.ts | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/app/api/canvas/local-edit/route.ts b/app/api/canvas/local-edit/route.ts
index 443f8aefc..04a54f42f 100644
--- a/app/api/canvas/local-edit/route.ts
+++ b/app/api/canvas/local-edit/route.ts
@@ -1425,8 +1425,16 @@ function filterScaleAdjustStructureComponents(params: {
       const componentBoxArea = Math.max(1, componentWidth * componentHeight);
       const componentDensity = area / componentBoxArea;
       const centerXRatio = (minX + componentWidth / 2) / width;
+      const centerYRatio = (minY + componentHeight / 2) / height;
+      const touchesTop = minY <= height * 0.04;
       const touchesRight = maxX >= width * 0.88;
       const edgeSliver = touchesRight && componentWidth < width * 0.18;
+      const broadTopBackground =
+        touchesTop &&
+        centerYRatio <= 0.45 &&
+        componentWidth >= width * 0.42 &&
+        componentHeight >= height * 0.18 &&
+        componentDensity >= 0.18;
       const elongated =
         componentHeight > componentWidth * 2.4 ||
         componentWidth > componentHeight * 2.4;
@@ -1442,7 +1450,12 @@ function filterScaleAdjustStructureComponents(params: {
         componentDensity >= 0.035 &&
         componentDensity <= 0.72;
 
-      if (likelyStructure && centeredEnough && !edgeSliver) {
+      if (
+        likelyStructure &&
+        centeredEnough &&
+        !edgeSliver &&
+        !broadTopBackground
+      ) {
         if (fillSurfaceComponent) {
           for (let fillY = minY; fillY <= maxY; fillY += 1) {
             for (let fillX = minX; fillX <= maxX; fillX += 1) {