From 6baeb57cde209904e462a1fea4c395530effe252 Mon Sep 17 00:00:00 2001
From: 134 <a134@134deMacBook-Pro.local>
Date: Sat, 4 Jul 2026 11:06:21 +0800
Subject: [PATCH] fix: accept visual shrink scale edits

---
 app/api/canvas/local-edit/route.ts |  7 +++----
 lib/canvas/generate-image.ts       | 13 ++++++++++++-
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/app/api/canvas/local-edit/route.ts b/app/api/canvas/local-edit/route.ts
index fe3503a97..4e30111f9 100644
--- a/app/api/canvas/local-edit/route.ts
+++ b/app/api/canvas/local-edit/route.ts
@@ -2625,10 +2625,9 @@ async function createScaleAdjustPatchReference(params: {
   } = params;
   const workspaceRect = getScaleAdjustPatchWorkspaceRect(regions, scalePercent);
   const workspacePixelRect = rectToPixels(workspaceRect, sourceWidth, sourceHeight);
-  const structureLockedDraft = hasScaleAdjustStructureTarget(
-    regions,
-    scalePercent
-  );
+  // Pixel-mask structure drafts are useful for enlargement, but in shrink
+  // cases they can turn dense interior details into black mask blocks.
+  const structureLockedDraft = hasScaleAdjustEnlargeTarget(regions, scalePercent);
   const targetDraftBuffer = await buildScaleAdjustVisualLayoutGuideBuffer({
     regions,
     scalePercent,
diff --git a/lib/canvas/generate-image.ts b/lib/canvas/generate-image.ts
index 0dd666870..981dd721a 100644
--- a/lib/canvas/generate-image.ts
+++ b/lib/canvas/generate-image.ts
@@ -189,6 +189,7 @@ const SCALE_ADJUST_MARKER_CLEANUP_MARGIN = 0.035;
 const SCALE_ADJUST_MARKER_DILATE_RADIUS = 3;
 const SCALE_ADJUST_MARKER_MIN_PIXEL_COUNT = 18;
 const SCALE_ADJUST_DIFF_SAMPLE_SIZE = 112;
+const SCALE_ADJUST_FOOTPRINT_FALLBACK_DIFF_THRESHOLD = 18;
 const SCALE_ADJUST_FALLBACK_MASK_DISTANCE_THRESHOLD = 42;
 const SCALE_ADJUST_FALLBACK_MASK_LUMA_GAP = 18;
 const SCALE_ADJUST_FALLBACK_INPAINT_ITERATIONS = 180;
@@ -1582,7 +1583,15 @@ async function applyScaleAdjustVerificationToImages(params: {
     const visuallyChangedInside = changeDiffScores.some(
       (score) => score >= SCALE_ADJUST_VISUAL_DIFF_THRESHOLD
     );
-    const changedInside = visuallyChangedInside && footprintStats.passed;
+    const footprintFallbackAccepted =
+      visuallyChangedInside &&
+      !footprintStats.passed &&
+      changeDiffScores.some(
+        (score) => score >= SCALE_ADJUST_FOOTPRINT_FALLBACK_DIFF_THRESHOLD
+      );
+    const changedInside =
+      (visuallyChangedInside && footprintStats.passed) ||
+      footprintFallbackAccepted;
     const outsideChanged =
       isScaleAdjustOutsideChanged(outsideDiffScores) ||
       isScaleAdjustOutsidePixelChanged(outsidePixelStats);
@@ -1591,6 +1600,7 @@ async function applyScaleAdjustVerificationToImages(params: {
     console.info("[Canvas Generate Image] Scale adjust result guard:", {
       debugLabel,
       changedInside,
+      footprintFallbackAccepted,
       footprintChanged: footprintStats.passed,
       footprintStats: {
         failedRegionCount: footprintStats.failedRegionCount,
@@ -1669,6 +1679,7 @@ async function applyScaleAdjustVerificationToImages(params: {
         imageIndex: index,
         reasons: guardWarnings,
         changedInside,
+        footprintFallbackAccepted,
         footprintChanged: footprintStats.passed,
         footprintStats: {
           failedRegionCount: footprintStats.failedRegionCount,