fix: improve material preview loading

app/api/agent-workflow/material-search/route.ts

@@ -34,6 +34,7 @@ type ExternalImageRecord = {
   label?: string;
   fileName?: string;
   fileSize?: number;
+  previewUrl?: string;
   downloadUrl?: string;
 };
 
@@ -81,6 +82,7 @@ type MaterialSearchImage = {
   label: string;
   fileName: string;
   imageUrl: string;
+  previewUrl: string | null;
   assetId: string | null;
   mimeType: string;
   group: "fixed" | "other";
@@ -611,6 +613,7 @@ function mapExternalImage(params: {
     label: String(params.image.label || "").trim() || `图片${params.sortOrder + 1}`,
     fileName: filename,
     imageUrl: downloadUrl,
+    previewUrl: String(params.image.previewUrl || "").trim() || null,
     assetId: null,
     mimeType: inferMimeTypeFromFilename(filename),
     group: params.group,

components/agents/AgentPreviewImage.tsx

@@ -18,6 +18,9 @@ type AgentPreviewImageProps = Omit<
   previewWidth?: number;
   previewQuality?: number;
   previewFormat?: "webp" | "avif" | "jpeg" | "png";
+  delivery?: "display" | "proxy";
+  fallbackSrc?: string | null;
+  fallbackToOriginal?: boolean;
   rootMargin?: string;
   eager?: boolean;
   raw?: boolean;
@@ -31,6 +34,7 @@ function buildPreviewUrl(params: {
   width: number;
   quality: number;
   format: "webp" | "avif" | "jpeg" | "png";
+  delivery?: "display" | "proxy";
   raw?: boolean;
 }) {
   if (params.raw) return params.src;
@@ -39,6 +43,7 @@ function buildPreviewUrl(params: {
       width: params.width,
       quality: params.quality,
       format: params.format,
+      delivery: params.delivery,
     }) || params.src
   );
 }
@@ -48,6 +53,9 @@ function AgentPreviewImageBase({
   previewWidth = 480,
   previewQuality = 78,
   previewFormat = "webp",
+  delivery = "display",
+  fallbackSrc,
+  fallbackToOriginal = true,
   rootMargin = "640px 0px",
   eager = false,
   raw = false,
@@ -58,15 +66,22 @@ function AgentPreviewImageBase({
   const imageRef = useRef<HTMLImageElement | null>(null);
   const [shouldLoad, setShouldLoad] = useState(eager);
   const [useOriginal, setUseOriginal] = useState(false);
+  const [useFallbackSource, setUseFallbackSource] = useState(false);
   const normalizedSrc = String(src || "").trim();
+  const normalizedFallbackSrc = String(fallbackSrc || "").trim();
+  const currentSrc =
+    useFallbackSource && normalizedFallbackSrc
+      ? normalizedFallbackSrc
+      : normalizedSrc;
 
   useEffect(() => {
     setUseOriginal(false);
+    setUseFallbackSource(false);
     setShouldLoad(eager);
-  }, [eager, normalizedSrc]);
+  }, [eager, normalizedFallbackSrc, normalizedSrc]);
 
   useEffect(() => {
-    if (eager || shouldLoad || !normalizedSrc) return;
+    if (eager || shouldLoad || !currentSrc) return;
     const image = imageRef.current;
     if (!image) return;
 
@@ -86,20 +101,22 @@ function AgentPreviewImageBase({
     );
     observer.observe(image);
     return () => observer.disconnect();
-  }, [eager, normalizedSrc, rootMargin, shouldLoad]);
+  }, [currentSrc, eager, rootMargin, shouldLoad]);
 
   const displaySrc = useMemo(() => {
-    if (!normalizedSrc || !shouldLoad) return EMPTY_PIXEL;
-    if (useOriginal) return normalizedSrc;
+    if (!currentSrc || !shouldLoad) return EMPTY_PIXEL;
+    if (useOriginal) return currentSrc;
     return buildPreviewUrl({
-      src: normalizedSrc,
+      src: currentSrc,
       width: previewWidth,
       quality: previewQuality,
       format: previewFormat,
+      delivery,
       raw,
     });
   }, [
-    normalizedSrc,
+    currentSrc,
+    delivery,
     previewFormat,
     previewQuality,
     previewWidth,
@@ -117,10 +134,20 @@ function AgentPreviewImageBase({
       loading={eager ? "eager" : "lazy"}
       decoding="async"
       onError={(event) => {
-        if (normalizedSrc && !useOriginal && displaySrc !== normalizedSrc) {
+        if (
+          fallbackToOriginal &&
+          currentSrc &&
+          !useOriginal &&
+          displaySrc !== currentSrc
+        ) {
           setUseOriginal(true);
           return;
         }
+        if (!useFallbackSource && normalizedFallbackSrc) {
+          setUseFallbackSource(true);
+          setUseOriginal(false);
+          return;
+        }
         onError?.(event);
       }}
       onLoad={onLoad}

components/agents/AgentWorkflowMaterialPicker.tsx

@@ -75,6 +75,17 @@ const MaterialImageCard = memo(function MaterialImageCard({
   onToggle: (imageId: string) => void;
 }) {
   const isPlaceholder = !String(image.imageUrl || "").trim();
+  const previewUrl = String(image.previewUrl || "").trim();
+  const displayImageUrl = previewUrl || String(image.imageUrl || "").trim();
+  const fallbackImageUrl = previewUrl ? String(image.imageUrl || "").trim() : null;
+  const [imageStatus, setImageStatus] = useState<"loading" | "loaded" | "error">(
+    isPlaceholder ? "loaded" : "loading"
+  );
+
+  useEffect(() => {
+    setImageStatus(isPlaceholder ? "loaded" : "loading");
+  }, [displayImageUrl, fallbackImageUrl, isPlaceholder]);
+
   return (
     <button
       type="button"
@@ -109,16 +120,41 @@ const MaterialImageCard = memo(function MaterialImageCard({
           </div>
         ) : (
           <AgentPreviewImage
-            src={image.imageUrl}
+            src={displayImageUrl}
+            fallbackSrc={fallbackImageUrl}
             alt={image.label}
-            className="h-full w-full object-cover"
+            className={cn(
+              "h-full w-full object-contain transition-opacity duration-300",
+              imageStatus === "loaded" ? "opacity-100" : "opacity-0"
+            )}
+            delivery="proxy"
+            eager
+            fallbackToOriginal={false}
             previewWidth={480}
             previewQuality={74}
-            onError={(event) => {
-              event.currentTarget.style.display = "none";
+            onError={() => {
+              setImageStatus("error");
             }}
+            onLoad={() => setImageStatus("loaded")}
           />
         )}
+        {!isPlaceholder && imageStatus !== "loaded" ? (
+          <div className="absolute inset-0 flex flex-col items-center justify-center gap-3 bg-[radial-gradient(circle_at_top,rgba(16,185,129,0.16),transparent_58%),linear-gradient(180deg,rgba(255,255,255,0.07),rgba(255,255,255,0.02))] px-4 text-center text-white/70">
+            {imageStatus === "error" ? (
+              <ImageIcon className="h-7 w-7 text-white/45" />
+            ) : (
+              <Loader2 className="h-6 w-6 animate-spin text-emerald-200/80" />
+            )}
+            <div className="text-xs font-medium">
+              {imageStatus === "error" ? "预览暂不可用" : "正在加载预览"}
+            </div>
+            <div className="max-w-[180px] text-[11px] leading-5 text-white/45">
+              {imageStatus === "error"
+                ? "原图地址仍可用于后续生成，可先选中或稍后重试。"
+                : "已命中素材，正在拉取缩略预览。"}
+            </div>
+          </div>
+        ) : null}
         <div className="absolute inset-x-0 top-0 flex items-center justify-between px-2 py-2">
           <span className="rounded-full bg-black/60 px-2 py-1 text-[11px] text-white">
             {isPlaceholder ? "加载中" : image.group === "fixed" ? "固定角度" : "其他图片"}

lib/agents/workflow-material-config.ts

@@ -41,6 +41,7 @@ function normalizeMaterialImage(
 
   const id = sanitizeText(raw.id, 128) || `image-${index + 1}`;
   const group = raw.group === "other" ? "other" : "fixed";
+  const previewUrl = sanitizeText(raw.previewUrl, 2000) || null;
 
   return {
     id,
@@ -48,6 +49,7 @@ function normalizeMaterialImage(
     label: sanitizeText(raw.label, 128) || `图片${index + 1}`,
     fileName: sanitizeText(raw.fileName, 255) || `image-${index + 1}`,
     imageUrl,
+    previewUrl,
     assetId: sanitizeText(raw.assetId, 128) || null,
     mimeType: sanitizeText(raw.mimeType, 128) || null,
     appearanceSummary: sanitizeText(raw.appearanceSummary, 255) || null,

types/agent.ts

@@ -272,6 +272,7 @@ export interface AgentWorkflowMaterialImage {
   label: string;
   fileName: string;
   imageUrl: string;
+  previewUrl?: string | null;
   assetId?: string | null;
   mimeType?: string | null;
   appearanceSummary?: string | null;