fix: improve structure locked scale drafts

app/api/canvas/local-edit/route.ts

@@ -1149,6 +1149,51 @@ function isScaleAdjustLikelyWhiteFabricPixel(
   );
 }
 
+function isScaleAdjustPersonLikePrompt(prompt: string) {
+  const text = normalizeScaleAdjustModelText(prompt);
+  return /person|people|human|woman|man|girl|boy|model|face|body|hand|arm|leg|clothing|人物|人像|真人|模特|女人|男人|女孩|男孩|小孩|脸|身体|手|胳膊|腿|衣服/.test(
+    text
+  );
+}
+
+function hasScaleAdjustPersonPixelSignal(params: {
+  box: { left: number; top: number; width: number; height: number };
+  raw: Buffer;
+  width: number;
+}) {
+  const { box, raw, width } = params;
+  let sampled = 0;
+  let skin = 0;
+  let whiteFabric = 0;
+  const step = Math.max(1, Math.floor(Math.min(box.width, box.height) / 260));
+
+  for (let localY = 0; localY < box.height; localY += step) {
+    const y = box.top + localY;
+    for (let localX = 0; localX < box.width; localX += step) {
+      const x = box.left + localX;
+      const rawIndex = getScaleAdjustRawPixelIndex(width, x, y);
+      const r = raw[rawIndex] || 0;
+      const g = raw[rawIndex + 1] || 0;
+      const b = raw[rawIndex + 2] || 0;
+      const { luma, saturation } = getScaleAdjustPixelStats(r, g, b);
+      sampled += 1;
+      if (isScaleAdjustLikelySkinPixel(r, g, b)) {
+        skin += 1;
+      } else if (
+        isScaleAdjustLikelyWhiteFabricPixel(r, g, b, luma, saturation) &&
+        luma < 242
+      ) {
+        whiteFabric += 1;
+      }
+    }
+  }
+
+  if (sampled <= 0) return false;
+  const skinRatio = skin / sampled;
+  const fabricRatio = whiteFabric / sampled;
+  return skin >= 18 && skinRatio >= 0.0025 && fabricRatio >= 0.035;
+}
+
 function estimateScaleAdjustBoxBackground(params: {
   box: { left: number; top: number; width: number; height: number };
   raw: Buffer;
@@ -1230,10 +1275,11 @@ function dilateScaleAdjustStructureMask(params: {
 
 function buildScaleAdjustStructureInitialMask(params: {
   box: { left: number; top: number; width: number; height: number };
+  includePersonPixels?: boolean;
   raw: Buffer;
   width: number;
 }) {
-  const { box, raw, width } = params;
+  const { box, includePersonPixels = false, raw, width } = params;
   const background = estimateScaleAdjustBoxBackground(params);
   const mask = new Uint8Array(box.width * box.height);
 
@@ -1247,16 +1293,38 @@ function buildScaleAdjustStructureInitialMask(params: {
       const g = raw[rawIndex + 1] || 0;
       const b = raw[rawIndex + 2] || 0;
       const { luma, saturation } = getScaleAdjustPixelStats(r, g, b);
-      if (isScaleAdjustLikelySkinPixel(r, g, b)) continue;
-      if (isScaleAdjustLikelyWhiteFabricPixel(r, g, b, luma, saturation)) {
-        continue;
-      }
-
+      const likelySkin = isScaleAdjustLikelySkinPixel(r, g, b);
+      const likelyWhiteFabric = isScaleAdjustLikelyWhiteFabricPixel(
+        r,
+        g,
+        b,
+        luma,
+        saturation
+      );
       const colorDistance = Math.sqrt(
         (r - background.r) ** 2 +
           (g - background.g) ** 2 +
           (b - background.b) ** 2
       );
+
+      if (includePersonPixels && likelySkin) {
+        mask[localY * box.width + localX] = 255;
+        continue;
+      }
+      if (
+        includePersonPixels &&
+        likelyWhiteFabric &&
+        luma < 246 &&
+        (colorDistance > 12 || luma < background.luma - 4)
+      ) {
+        mask[localY * box.width + localX] = 255;
+        continue;
+      }
+      if (likelySkin) continue;
+      if (likelyWhiteFabric) {
+        continue;
+      }
+
       const darkStructure = luma < Math.min(136, background.luma - 38);
       const saturatedStructure =
         saturation > 0.16 && luma < 218 && colorDistance > 38;
@@ -1596,14 +1664,22 @@ async function buildScaleAdjustMaskWashPatch(params: {
 }
 
 async function buildScaleAdjustStructureLockedComposite(params: {
+  includePersonPixels?: boolean;
   placement: ReturnType<typeof getScaleAdjustVisualGuidePlacement>;
   raw: Buffer;
   sourceBuffer: Buffer;
   sourceWidth: number;
 }) {
-  const { placement, raw, sourceBuffer, sourceWidth } = params;
+  const {
+    includePersonPixels = false,
+    placement,
+    raw,
+    sourceBuffer,
+    sourceWidth,
+  } = params;
   const initialMask = buildScaleAdjustStructureInitialMask({
     box: placement.sourceBox,
+    includePersonPixels,
     raw,
     width: sourceWidth,
   });
@@ -1860,6 +1936,13 @@ async function buildScaleAdjustVisualLayoutGuideBuffer(params: {
       (targetWidthFactor > 1.08 || targetHeightFactor > 1.08);
     const structureLockedComposite = shouldUseStructureLock
       ? await buildScaleAdjustStructureLockedComposite({
+          includePersonPixels:
+            isScaleAdjustPersonLikePrompt(region.prompt) ||
+            hasScaleAdjustPersonPixelSignal({
+              box: placement.sourceBox,
+              raw: sourceRaw,
+              width: sourceWidth,
+            }),
           placement,
           raw: sourceRaw,
           sourceBuffer,
@@ -3154,7 +3237,8 @@ export async function POST(request: NextRequest) {
         : [];
     const useScaleAdjustPatchTargetDraftPrimary = Boolean(scaleAdjustPatchReference);
     const includeScaleAdjustPatchSourceReference =
-      scaleAdjustPatchReference?.structureLockedDraft === true;
+      Boolean(scaleAdjustPatchReference) &&
+      scaleAdjustPatchReference?.structureLockedDraft !== true;
     const prompt = isScaleAdjustOperation
       ? scaleAdjustPatchReference
         ? buildScaleAdjustPatchPrompt(