fix: soften scale adjust composite edges

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

@@ -729,6 +729,7 @@ function buildScaleAdjustPrompt(
     `4. 放大时，目标主体应围绕原位置视觉中心自然变大到约 ${targetLabel}；宽度和高度都要同步变大，不能出现“高度变高但宽度变窄”的非等比变形；主体边缘与遮挡关系要合理，不能产生突兀裁切。`,
     "5. 如果主体靠近画布边界导致目标尺寸空间不足，请用能完整放入画面的最大统一倍率整体缩放；绝不能为了塞进画面而只压缩宽度或只拉伸高度。",
     "6. 框选区域内非目标主体的背景、墙面、桌面、植物、文字和其它物体应保持原场景逻辑，不要跟着主体一起缩放。",
+    "6.1 比例调整后的主体边缘必须和周围环境自然融合，选区边界不能被肉眼看出；不得出现一整块矩形区域清晰度、颜色、光照、纹理或透视突然变化。",
     "7. 未受比例调整影响的其它画面区域必须保持原图不变，尤其是框选区域外的文字、Logo、标题、尺寸标注、装饰条和页面排版不得被清理、改写、模糊或重绘。",
     "8. 最终输出必须是一张完整、干净、无缝的照片，不得出现任何选区框、说明文字、对比线、比例数字或 UI 元素。",
     "9. 输出前自检：如果目标主体大小与原图相比没有明显变化，或者主体宽高比发生非等比变形，必须重新生成；禁止返回看起来和原图相同或被拉伸的结果。",

lib/canvas/generate-image.ts

@@ -112,8 +112,8 @@ class ScaleAdjustOutputRejectedError extends Error {
 const LOCAL_EDIT_COMPOSITE_PADDING_RATIO = 0.14;
 const LOCAL_EDIT_COMPOSITE_MIN_PADDING_RATIO = 0.012;
 const LOCAL_EDIT_COMPOSITE_MAX_PADDING_RATIO = 0.06;
-const LOCAL_EDIT_COMPOSITE_FEATHER_MIN_PX = 10;
-const LOCAL_EDIT_COMPOSITE_FEATHER_MAX_PX = 44;
+const LOCAL_EDIT_COMPOSITE_FEATHER_MIN_PX = 18;
+const LOCAL_EDIT_COMPOSITE_FEATHER_MAX_PX = 72;
 const SCALE_ADJUST_VISUAL_DIFF_THRESHOLD = 14;
 const SCALE_ADJUST_OUTSIDE_DIFF_THRESHOLD = 18;
 const SCALE_ADJUST_OUTSIDE_DIFF_MIN_CHANGED_RATIO = 0.28;
@@ -678,10 +678,10 @@ function buildLocalEditCompositeMaskSvg(params: {
     LOCAL_EDIT_COMPOSITE_FEATHER_MIN_PX,
     Math.min(
       LOCAL_EDIT_COMPOSITE_FEATHER_MAX_PX,
-      Math.round(Math.min(width, height) * 0.012)
+      Math.round(Math.min(width, height) * 0.018)
     )
   );
-  const rects = regions
+  const rectEntries = regions
     .map((region) => {
       const left = Math.max(0, Math.round(region.x * width));
       const top = Math.max(0, Math.round(region.y * height));
@@ -693,7 +693,33 @@ function buildLocalEditCompositeMaskSvg(params: {
         height - top,
         Math.max(1, Math.round(region.height * height))
       );
-      return `<rect x="${left}" y="${top}" width="${rectWidth}" height="${rectHeight}" rx="${Math.round(blur * 0.9)}" fill="#ffffff" />`;
+      return { left, top, rectHeight, rectWidth };
+    })
+    .filter(({ rectHeight, rectWidth }) => rectWidth > 0 && rectHeight > 0);
+  const softRects = rectEntries
+    .map(
+      ({ left, top, rectHeight, rectWidth }) =>
+        `<rect x="${left}" y="${top}" width="${rectWidth}" height="${rectHeight}" rx="${Math.round(
+          blur * 0.9
+        )}" fill="#ffffff" />`
+    )
+    .join("");
+  const coreRects = rectEntries
+    .map(({ left, top, rectHeight, rectWidth }) => {
+      const inset = Math.max(
+        0,
+        Math.min(
+          Math.round(blur * 1.35),
+          Math.floor(rectWidth / 3),
+          Math.floor(rectHeight / 3)
+        )
+      );
+      const coreWidth = rectWidth - inset * 2;
+      const coreHeight = rectHeight - inset * 2;
+      if (coreWidth <= 0 || coreHeight <= 0) return "";
+      return `<rect x="${left + inset}" y="${top + inset}" width="${coreWidth}" height="${coreHeight}" rx="${Math.round(
+        blur * 0.45
+      )}" fill="#ffffff" />`;
     })
     .join("");
 
@@ -706,9 +732,9 @@ function buildLocalEditCompositeMaskSvg(params: {
       </defs>
       <rect x="0" y="0" width="${width}" height="${height}" fill="rgba(0,0,0,0)" />
       <g filter="url(#local-edit-soft-mask)">
-        ${rects}
+        ${softRects}
       </g>
-      ${rects}
+      ${coreRects}
     </svg>
   `);
 }