fix(realtime-canvas): enforce sketch-preserving i2i defaults

app/api/realtime/config/route.ts

@@ -36,9 +36,9 @@ const defaultConfig = {
   model: {
     id: "runware:101@1",
     defaults: {
-      steps: 4,
-      cfgScale: 3.5,
-      strength: 0.85,
+      steps: 8,
+      cfgScale: 6,
+      strength: 0.4,
       imageSize: "square" as const,
     },
     limits: {
@@ -117,21 +117,18 @@ export async function GET() {
     defaultConfig.model.limits.steps.min,
     defaultConfig.model.limits.steps.max
   );
+  const legacyScheduleMu = Number(config.defaults?.scheduleMu);
+  const cfgScaleBase = Number(
+    config.defaults?.cfgScale ??
+      (Number.isFinite(legacyScheduleMu) ? legacyScheduleMu * 2.5 : defaultConfig.model.defaults.cfgScale)
+  );
   const cfgScale = clamp(
-    Number(
-      config.defaults?.cfgScale ??
-        config.defaults?.scheduleMu ??
-        defaultConfig.model.defaults.cfgScale
-    ),
+    cfgScaleBase,
     defaultConfig.model.limits.cfgScale.min,
     defaultConfig.model.limits.cfgScale.max
   );
   const strength = clamp(
-    Number(
-      config.defaults?.strength ??
-        config.defaults?.feedback ??
-        defaultConfig.model.defaults.strength
-    ),
+    Number(config.defaults?.strength ?? defaultConfig.model.defaults.strength),
     defaultConfig.model.limits.strength.min,
     defaultConfig.model.limits.strength.max
   );

app/api/realtime/generate/route.ts

@@ -115,23 +115,24 @@ export async function POST(request: Request) {
   const maxInputResolution = clamp(Number(config.maxInputResolution || 1024), 512, 1536);
   const size = resolveSquareSize(body.imageSize, maxInputResolution);
   const steps = clamp(
-    Number(body.steps || config.defaults?.steps || 4),
+    Number(body.steps || config.defaults?.steps || 8),
     1,
     8
   );
   const cfgScale = clamp(
-    Number(body.cfgScale || config.defaults?.cfgScale || 3.5),
+    Number(body.cfgScale || config.defaults?.cfgScale || 6),
     1,
     12
   );
   const strength = clamp(
-    Number(body.strength || config.defaults?.strength || 0.85),
+    Number(body.strength || config.defaults?.strength || 0.4),
     0.05,
     1
   );
 
   const positivePrompt =
-    String(body.prompt || "").trim() || "将草图渲染为高质感产品设计图，保持结构和主轮廓一致。";
+    String(body.prompt || "").trim() ||
+    "严格按照输入草图生成：保持主体轮廓、位置、比例和数量一致，只做材质与光影细化；禁止改变构图，禁止新增无关背景纹理。";
 
   const requestInference = async (modelId: string) => {
     const taskUUID = crypto.randomUUID();

components/canvas/RealtimeCanvasDialog.tsx

@@ -67,7 +67,8 @@ type RealtimeCanvasDialogProps = {
   onApplyResult: (payload: { imageUrl: string; prompt: string }) => void;
 };
 
-const FALLBACK_PROMPT = "将草图渲染为高质感产品设计图，保持结构和主轮廓一致。";
+const FALLBACK_PROMPT =
+  "严格按照输入草图生成：保持主体轮廓、位置、比例和数量一致，只做材质与光影细化；禁止改变构图，禁止新增无关背景纹理。";
 const CANVAS_BACKGROUND = "#ffffff";
 const BRUSH_COLOR_PRESETS = [
   "#18181b",
@@ -91,9 +92,9 @@ const defaultRealtimeConfig: RealtimeConfig = {
   model: {
     id: "runware:101@1",
     defaults: {
-      steps: 4,
-      cfgScale: 3.5,
-      strength: 0.85,
+      steps: 8,
+      cfgScale: 6,
+      strength: 0.4,
       imageSize: "square",
     },
   },