fix: restore canvas generation placeholders

components/canvas/CanvasChatPanel.tsx

@@ -7631,6 +7631,10 @@ export function CanvasChatPanel({
       textContent = `请按「${selectedSkillTag.name}」标签的要求处理。`;
     }
     textContent = clampChatRequestText(textContent, MAX_CHAT_TEXT_PART_LENGTH);
+    const requestModel = allModels.find((model) => model.id === effectiveModelId);
+    const shouldShowOptimisticImageGeneration =
+      effectiveComposerMode === "image" &&
+      Boolean(requestModel && isCanvasImageModel(requestModel));
 
     // 🆕 隐藏提示词（不在 UI 中展示）
     const hiddenSegments: string[] = [];
@@ -7728,6 +7732,16 @@ export function CanvasChatPanel({
       inFlightRawChatIdRef.current = rawChatId;
       clearStreamImageGenerationStateForChat(activeChatId);
       clearAgentProgressStateForChat(activeChatId);
+      if (shouldShowOptimisticImageGeneration) {
+        const imageParamSnapshot = imageParamsRef.current || imageParams;
+        setStreamImageGenerationStateForChat(activeChatId, {
+          phase: "processing",
+          providerType: requestModel?.providerType,
+          modelName: getAgentSafeModelName(requestModel?.displayName),
+          imageCount:
+            Math.max(1, Math.round(Number(imageParamSnapshot?.imageCount || 1))) || 1,
+        });
+      }
 
       // 使用与 multimodal-input 相同的格式发送消息
       try {
@@ -7737,6 +7751,9 @@ export function CanvasChatPanel({
       });
     } catch (error) {
       releaseSendGuard(activeChatId);
+      if (shouldShowOptimisticImageGeneration) {
+        clearStreamImageGenerationStateForChat(activeChatId);
+      }
       if (inFlightChatIdRef.current === activeChatId) {
         inFlightChatIdRef.current = null;
         inFlightRawChatIdRef.current = null;
@@ -7778,10 +7795,13 @@ export function CanvasChatPanel({
     clearSelection,
     buildAutoContext,
     buildContextPayload,
+    allModels,
     isVideoModel,
+    isCanvasImageModel,
     videoParams,
     videoFrameSlots.length,
     currentModel?.providerType,
+    imageParams,
     selectedImageNodes,
     isDetailGenerationMode,
     canUseDetailGeneration,
@@ -7790,6 +7810,7 @@ export function CanvasChatPanel({
     getSendGuard,
     clearStreamImageGenerationStateForChat,
     clearAgentProgressStateForChat,
+    setStreamImageGenerationStateForChat,
     computedComposerMode,
     releaseSendGuard,
     setSendGuard,

components/image-params-bar.tsx

@@ -191,18 +191,22 @@ export function ImageParamsBar({
     a.watermark === b.watermark &&
     a.seed === b.seed;
 
-  const buildBaseParams = (source?: Partial<ImageGenerationParams>) =>
+  const buildBaseParams = (source?: Partial<ImageGenerationParams>) => {
-    clampParamsByProvider({
+    const hasSourceAspectRatio =
+      typeof source?.aspectRatio === "string" && source.aspectRatio.trim().length > 0;
+
+    return clampParamsByProvider({
       aspectRatio: inlineTheme === "minimal" ? "1:1" : "auto",
       imageSize: "2K",
       imageCount: 1,
       promptExtend: true,
       watermark: false,
       ...source,
-      ...(inlineTheme === "minimal" && (!source?.aspectRatio || source.aspectRatio === "auto")
+      ...(inlineTheme === "minimal" && !hasSourceAspectRatio
         ? { aspectRatio: "1:1" }
         : {}),
     });
+  };
 
   const [params, setParams] = useState<ImageGenerationParams>({
     ...buildBaseParams(initialParams),