perf(双端优化): 优化双端加载与资源复用

assets/webui/ofdgo.js

@@ -4128,6 +4128,7 @@ async function refreshEditorPage(doc, index, openSeq, clearSelection = false) {
 }
 
 function releasePageResources() {
+	if (state.pageInFlight.size) return;
 	const images = new Set(), fonts = new Set();
 	for (const page of state.pageCache.values()) {
 		for (const name of page.imageNames) images.add(name);
@@ -4568,7 +4569,7 @@ async function loadWASM() {
 	state.ready = false;
 	state.wasmExited = false;
 	await new Promise((resolve, reject) => {
-		const worker = createEngineWorker();
+		const worker = createEngineWorker({pages: true});
 		wasmWorker = worker;
 		const fail = (err) => {
 			markWASMExited(wasmSeq, err);
@@ -5473,6 +5474,9 @@ async function openDocument(options = {}) {
 		if (openSeq !== state.openSeq) {
 			return;
 		}
+		wasmWorker.configurePages?.(!state.editorInfo && !doc.encrypted && state.ofdBytes ? {
+			file: state.ofdBytes, fonts, annotations: state.renderAnnotations, document: doc.documentIndex, version: doc.documentVersion
+		} : null);
 		if (options.keepPreview) {
 			resetPageLoading();
 			state.pageCache.clear();
@@ -8724,7 +8728,7 @@ async function exportFile(whole, indices = null, value = el.exportFormat.value,
 			updateControls();
 		}
 		const result = readingSave
-			? { label: "OFD", size: state.ofdBytes.byteLength, mime, blob: state.ofdBytes }
+			? { label: "OFD", size: state.ofdBytes.size ?? state.ofdBytes.byteLength, mime, blob: state.ofdBytes }
 			: saving ? await callWASM(background ? "ofdgoSaveSnapshot" : "ofdgoSaveDocument", indices, ...outputOptions, destination) : whole
 			? await callWASM("ofdgoExportDocument", format.value, dpi, indices, state.renderBackend, ...outputOptions, file)
 			: await callWASM("ofdgoExportPage", pageIndex, format.value, dpi, state.renderBackend, ...outputOptions, file);
@@ -8971,11 +8975,9 @@ function resetPageFlow(keepCache = false) {
 
 function resetPageLoading() {
 	releaseMediaPlayers();
-	if (nativeHost) {
 	for (const [id, request] of wasmRequests) {
 		if (request.name === "ofdgoRenderPage") wasmWorker?.postMessage({ type: "cancel", id });
 	}
-	}
 	for (const task of state.pageInFlight.values()) {
 		task.resolve(null);
 	}
@@ -9088,9 +9090,10 @@ function loadPageData(index, options = {}) {
 	const current = state.pageInFlight.get(key);
 	if (current) {
 		current.priority = Math.min(current.priority, priority);
+		if (current.preview && !options.preview) return current.promise.then(() => loadPageData(index, options));
 		return current.promise;
 	}
-	if (!options.refresh && state.pageCache.has(index)) {
+	if (!options.refresh && state.pageCache.has(index) && (options.preview || !state.pageCache.get(index).previewOnly)) {
 		const page = state.pageCache.get(index);
 		state.pageCache.delete(index);
 		state.pageCache.set(index, page);
@@ -9102,7 +9105,7 @@ function loadPageData(index, options = {}) {
 		resolve = done;
 		reject = fail;
 	});
-	const task = { key, index, openSeq, priority, refresh: options.refresh, resolve, reject, promise };
+	const task = { key, index, openSeq, priority, preview: !!options.preview, refresh: options.refresh, resolve, reject, promise };
 	state.pageInFlight.set(key, task);
 	state.pageRenderQueue.push(task);
 	schedulePageRender();
@@ -9112,7 +9115,7 @@ function loadPageData(index, options = {}) {
 function schedulePageRender() {
 	if (state.pageRenderRunning) {
 		if (state.pageRenderWorkers) {
-			while (state.pageRenderQueue.length && state.pageRenderWorkers < (nativeHost?.parallelism || 1)) processPageRenderTasks();
+			while (state.pageRenderQueue.length && state.pageRenderWorkers < (nativeHost?.parallelism || wasmWorker?.parallelism || 1)) processPageRenderTasks();
 		}
 		return;
 	}
@@ -9122,7 +9125,7 @@ function schedulePageRender() {
 
 async function processPageRenderQueue() {
 	await nextFrame();
-	await Promise.all(Array.from({ length: nativeHost?.parallelism || 1 }, () => processPageRenderTasks()));
+	await Promise.all(Array.from({ length: nativeHost?.parallelism || wasmWorker?.parallelism || 1 }, () => processPageRenderTasks()));
 }
 
 async function processPageRenderTasks() {
@@ -9139,12 +9142,12 @@ async function processPageRenderTasks() {
 					task.resolve(null);
 					continue;
 				}
-				if (!task.refresh && state.pageCache.has(task.index)) {
+				if (!task.refresh && state.pageCache.has(task.index) && (task.preview || !state.pageCache.get(task.index).previewOnly)) {
 					task.resolve(state.pageCache.get(task.index));
 					continue;
 				}
 				const args = [task.index, state.renderBackend, state.renderDPI, displayMode() === "raster"];
-				if (nativeHost) args.push([...state.svgFonts.keys()]);
+				args.push([...state.svgFonts.keys()], [...state.svgImages.keys()], task.preview);
 				const page = await callWASM("ofdgoRenderPage", ...args);
 				if (state.pageInFlight.get(task.key) !== task) {
 					task.resolve(null);
@@ -9230,7 +9233,7 @@ function trimPageCache() {
 		for (const name of page.imageNames) {
 			const count = references.get(name) - 1;
 			references.set(name, count);
-			if (count === 0) {
+			if (count === 0 && !state.pageInFlight.size) {
 				const image = state.svgImages.get(name);
 				bytes -= image.size;
 				URL.revokeObjectURL(image.url);
@@ -11197,7 +11200,7 @@ async function renderThumbnail(index, openSeq = state.openSeq) {
 	}
 	state.thumbnailInFlight.add(key);
 	try {
-		const page = await loadPageData(index, { openSeq, priority: 5 });
+		const page = await loadPageData(index, { openSeq, priority: 5, preview: true });
 		if (openSeq !== state.openSeq) {
 			return;
 		}
@@ -12547,11 +12550,11 @@ async function callWASM(name, ...args) {
 		}
 		try {
 			const transfer = [];
-			if (name === "ofdgoOpen" && !nativeHost) {
+			if (name === "ofdgoOpen" && !nativeHost && ArrayBuffer.isView(args[0])) {
 				args[0] = args[0].slice();
 				transfer.push(args[0].buffer);
 			}
-			if (name === "ofdgoLoadImport" && args[0] && !nativeHost) transfer.push(args[0].buffer);
+			if (name === "ofdgoLoadImport" && ArrayBuffer.isView(args[0]) && !nativeHost) transfer.push(args[0].buffer);
 			wasmWorker.postMessage({ id, name, args }, transfer);
 		} catch (err) {
 			wasmRequests.delete(id);

assets/webui/ofdgo_host.js

@@ -1,7 +1,8 @@
 let engineModule = null;
 
-export function createEngineWorker() {
+export function createEngineWorker(options = {}) {
 	if (nativeHost) return nativeHost.worker();
+	if (options.pages) return new BrowserEngine();
 	const worker = new Worker("./ofdgo_wasm.js");
 	worker.addEventListener("message", event => {
 		if (event.data.type !== "module") return;
@@ -13,7 +14,156 @@ export function createEngineWorker() {
 }
 
 export async function documentBytes(file) {
-	return file?.nativeFile ? file : new Uint8Array(await file.arrayBuffer());
+	if (file?.nativeFile) return file;
+	if (file instanceof Blob) return new Response(file.stream()).blob();
+	return new Uint8Array(await file.arrayBuffer());
+}
+
+class BrowserEngine {
+	constructor() {
+		this.primary = createEngineWorker();
+		this.primary.onmessage = event => {
+			const data = event.data;
+			if (data.memory) this.memory = data.memory;
+			if (data.id != null && !data.type) this.requests.delete(data.id);
+			this.onmessage?.(event);
+		};
+		this.primary.onerror = event => this.onerror?.(event);
+		this.primary.onmessageerror = event => this.onmessageerror?.(event);
+		this.requests = new Map();
+		this.slots = new Set();
+		this.sequence = 0;
+		this.revision = 0;
+		this.memory = 0;
+		this.parallelism = 1;
+		this.budget = Math.max(128, Math.min(1024, (navigator.deviceMemory || 2) * 128)) * 1024 * 1024;
+		this.closed = false;
+		this.source = null;
+	}
+
+	configurePages(source) {
+		this.invalidatePages();
+		if (!source || this.closed) return;
+		this.source = {...source, file: source.file instanceof Blob ? source.file : new Blob([source.file])};
+		this.parallelism = Math.max(1, Math.min(2, (navigator.hardwareConcurrency || 2) - 1, Math.floor(this.budget / (256 * 1024 * 1024))));
+	}
+
+	invalidatePages() {
+		this.revision++;
+		this.source = null;
+		this.parallelism = 1;
+		for (const slot of this.slots) this.closeSlot(slot);
+	}
+
+	closeSlot(slot, error = new DOMException("页面加载已取消", "AbortError")) {
+		if (!this.slots.delete(slot)) return;
+		slot.worker.terminate();
+		slot.rejectReady(error);
+		for (const pending of slot.pending.values()) pending.reject(error);
+		slot.pending.clear();
+	}
+
+	createSlot(source) {
+		const worker = createEngineWorker();
+		const slot = {worker, pending: new Map(), busy: false, memory: Math.max(128 << 20, this.memory)};
+		const ready = new Promise((resolve, reject) => {
+			slot.rejectReady = reject;
+			worker.onmessage = ({data}) => {
+				if (data.memory) slot.memory = data.memory;
+				if (data.type === "ready") { resolve(); return; }
+				if (data.type === "exit") { this.closeSlot(slot, new Error("页面加载失败")); return; }
+				if (data.type) return;
+				const request = slot.pending.get(data.id);
+				if (!request) return;
+				slot.pending.delete(data.id);
+				if (data.ok) request.resolve(data);
+				else request.reject(Object.assign(new Error(data.error), {code: data.code}));
+			};
+			worker.onerror = worker.onmessageerror = () => this.closeSlot(slot, new Error("页面加载失败"));
+		});
+		this.slots.add(slot);
+		slot.ready = ready.then(async () => {
+			let opened = await this.callSlot(slot, "ofdgoOpen", [source.file, source.fonts, source.annotations]);
+			if ((source.document || 0) !== (opened.data.documentIndex || 0)) opened = await this.callSlot(slot, "ofdgoSelectDocument", [source.document]);
+			if ((source.version || "") !== (opened.data.documentVersion || "")) await this.callSlot(slot, "ofdgoSelectVersion", [source.version || ""]);
+		});
+		slot.ready.catch(() => {});
+		return slot;
+	}
+
+	callSlot(slot, name, args) {
+		return new Promise((resolve, reject) => {
+			if (!this.slots.has(slot)) { reject(new DOMException("页面加载已取消", "AbortError")); return; }
+			const id = --this.sequence;
+			slot.pending.set(id, {resolve, reject});
+			try { slot.worker.postMessage({id, name, args}); }
+			catch (error) { slot.pending.delete(id); reject(error); }
+		});
+	}
+
+	postMessage(data, transfer) {
+		if (this.closed) return;
+		if (data.type === "cancel") {
+			const slot = this.requests.get(data.id);
+			if (slot) this.closeSlot(slot);
+			else this.primary.postMessage(data);
+			return;
+		}
+		if (!data.type && data.name !== "ofdgoRenderPage" && ![
+			"ofdgoDocumentInfo", "ofdgoDocumentVersions", "ofdgoDocumentNavigation", "ofdgoOpenLinks", "ofdgoOutlineLinks", "ofdgoRenderBackends", "ofdgoSVGFontData",
+			"ofdgoSearchPage", "ofdgoPageTextString", "ofdgoResources", "ofdgoResourceReferences", "ofdgoResourceTargets",
+			"ofdgoResourceLocations", "ofdgoFontPreview", "ofdgoFontFaces", "ofdgoFontFace", "ofdgoMatchFontFiles",
+			"ofdgoImages", "ofdgoStructureTargets", "ofdgoStructureObjects", "ofdgoPackageDocuments", "ofdgoVerifySignatures",
+			"ofdgoAnnotationInfos", "ofdgoInvoices", "ofdgoInvoice", "ofdgoExportInvoice", "ofdgoValidateInvoice",
+			"ofdgoActionList", "ofdgoPageSettings", "ofdgoReadAnnotation", "ofdgoPreviewSignatureSeal",
+			"ofdgoExportFormats", "ofdgoOutputFormats", "ofdgoParsePageRange", "ofdgoExportPage", "ofdgoExportDocument",
+			"ofdgoExportAttachment", "ofdgoExportResource", "ofdgoExportMedia", "ofdgoExportVersion"
+		].includes(data.name)) this.invalidatePages();
+		if (data.name !== "ofdgoRenderPage" || !this.source || ![...this.requests.values()].includes(null)) {
+			if (data.name === "ofdgoRenderPage") this.requests.set(data.id, null);
+			this.primary.postMessage(data, transfer);
+			return;
+		}
+		let slot = [...this.slots].find(slot => !slot.busy);
+		const memory = this.memory + [...this.slots].reduce((total, item) => total + item.memory, 0);
+		if (!slot && this.slots.size < this.parallelism - 1 && memory + Math.max(128 << 20, this.memory) <= this.budget) slot = this.createSlot(this.source);
+		if (!slot) {
+			this.requests.set(data.id, null);
+			this.primary.postMessage(data, transfer);
+			return;
+		}
+		slot.busy = true;
+		this.requests.set(data.id, slot);
+		const revision = this.revision;
+		let fallback = false;
+		slot.ready.then(() => this.callSlot(slot, data.name, data.args)).then(result => {
+			if (revision !== this.revision) throw new DOMException("页面加载已取消", "AbortError");
+			if (!this.closed) this.onmessage?.({data: {...result, id: data.id}});
+		}).catch(error => {
+			if (!this.closed && revision === this.revision && error.name !== "AbortError") {
+				this.closeSlot(slot, error);
+				this.parallelism = Math.max(1, this.slots.size + 1);
+				this.requests.set(data.id, null);
+				fallback = true;
+				this.primary.postMessage(data, transfer);
+				return;
+			}
+			if (!this.closed) this.onmessage?.({data: {id: data.id, ok: false, error: error.message, canceled: error.name === "AbortError"}});
+		}).finally(() => {
+			if (!fallback) this.requests.delete(data.id);
+			slot.busy = false;
+			const memory = this.memory + [...this.slots].reduce((total, item) => total + item.memory, 0);
+			if (memory > this.budget) { this.closeSlot(slot); this.parallelism = Math.max(1, this.slots.size + 1); }
+		});
+	}
+
+	terminate() {
+		if (this.closed) return;
+		this.closed = true;
+		this.invalidatePages();
+		this.primary.terminate();
+		this.requests.clear();
+	}
 }
 
 export function saveFilePicker(options) {

assets/webui/ofdgo_wasm.js

@@ -190,6 +190,10 @@ async function handleMessage({ id, name, args }) {
 	const password = converting ? args[2] : name === "ofdgoSetEncryption" ? args[0]?.password : name === "ofdgoOpen" ? args[3]?.password : name === "ofdgoLoadImport" ? args[1]?.password : null;
 	try {
 		signal?.throwIfAborted();
+		if (["ofdgoOpen", "ofdgoLoadImport", "ofdgoConvertPDF"].includes(name) && args[0] instanceof Blob) {
+			const file = args[0], reader = new FileReaderSync();
+			args[0] = {size: file.size, read: (offset, size) => new Uint8Array(reader.readAsArrayBuffer(file.slice(offset, offset + size)))};
+		}
 		if (name === "ofdgoDetectFormat") {
 			const file = args[0], reader = new FileReaderSync();
 			channel = new MessageChannel();
@@ -299,8 +303,8 @@ async function handleMessage({ id, name, args }) {
 			await output.abort();
 		}
 		output = null;
-		const transfer = result.data?.bytes ? [result.data.bytes.buffer] : (result.data?.images || []).map((image) => image.bytes.buffer);
-		self.postMessage({ id, ...result }, transfer);
+		const transfer = [...new Set([result.data?.bytes, ...(result.data?.images || []).map(image => image.bytes), ...(result.data?.fonts || []).map(font => font.data)].filter(bytes => bytes?.byteLength).map(bytes => bytes.buffer))];
+		self.postMessage({ id, ...result, memory: engineMemory.buffer.byteLength }, transfer);
 	} catch (err) {
 		await output?.abort().catch(() => {});
 		const result = { id, ok: false, error: err.message, errorName: err.name };

internal/webui/webui.go

@@ -313,6 +313,7 @@ type exportWriter struct {
 
 // browserReaderAt 分块读取浏览器文件，只缓存最近的一个数据块
 type browserReaderAt struct {
+	mu         sync.Mutex
 	read       platformValue
 	checkpoint platformValue
 	size       int64
@@ -461,14 +462,14 @@ func (s *Session) Close() error {
 		return nil
 	}
 	reader := s.Reader
-	source := s.input
+	input := s.input
 	*s = Session{}
 	var err error
 	if reader != nil {
 		err = reader.Close()
 	}
-	if source != nil {
-		err = errors.Join(err, source.Close())
+	if input != nil {
+		err = errors.Join(err, input.Close())
 	}
 	return err
 }
@@ -744,6 +745,13 @@ func (s *Session) RenderPageSVG(index int) (PageSVG, error) {
 // 入参: index 页面索引, backend 后端组合，空值沿用会话配置, dpi 光栅分辨率, raster 是否光栅显示
 // 返回: PageSVG 页面结果, error 错误信息
 func (s *Session) RenderPage(index int, backend string, dpi float64, raster bool) (PageSVG, error) {
+	return s.renderPage(index, backend, dpi, raster, false, nil)
+}
+
+// renderPage 按需生成预览及交互数据，省略调用方已持有的资源字节
+// 入参: index 页面索引, backend 后端组合, dpi 光栅分辨率, raster 光栅显示, preview 仅预览, known 已持有资源
+// 返回: PageSVG 页面结果, error 渲染错误
+func (s *Session) renderPage(index int, backend string, dpi float64, raster, preview bool, known map[string]bool) (PageSVG, error) {
 	if backend != "" {
 		if err := s.SetRenderBackend(backend); err != nil {
 			return PageSVG{}, err
@@ -759,7 +767,7 @@ func (s *Session) RenderPage(index int, backend string, dpi float64, raster bool
 	}
 	var buf bytes.Buffer
 	renderer := *s.Renderer
-	if s.cachedPageText(index) == nil {
+	if !preview && s.cachedPageText(index) == nil {
 		renderer.OnPageText = func(_ *ofdgo.PageContent, text *ofdgo.PageText) {
 			s.cachePageText(index, text)
 		}
@@ -767,10 +775,18 @@ func (s *Session) RenderPage(index int, backend string, dpi float64, raster bool
 	if raster {
 		renderer.DPI = dpi
 	}
-	resources, err := renderer.RenderPreview(page, &buf, ofdgo.PreviewOptions{Raster: raster, Objects: !raster && s.editing})
+	resources, err := renderer.RenderPreview(page, &buf, ofdgo.PreviewOptions{Raster: raster, Objects: !raster && s.editing && !preview, KnownResources: known})
 	if err != nil {
 		return PageSVG{}, err
 	}
+	clear(s.svgFonts)
+	for i, font := range resources.Fonts {
+		s.svgFonts[font.Name] = font.Data
+		resources.Fonts[i].Data = nil
+	}
+	if preview {
+		return PageSVG{Index: index, Number: index + 1, ID: page.ID, Width: box.W, Height: box.H, SVG: buf.String(), Fonts: resources.Fonts, Images: resources.Images}, nil
+	}
 	links, err := s.Renderer.PageLinks(page)
 	if err != nil {
 		return PageSVG{}, err
@@ -790,11 +806,6 @@ func (s *Session) RenderPage(index int, backend string, dpi float64, raster bool
 			annotations[i].Bounds, annotations[i].Contours = bounds, contours
 		}
 	}
-	clear(s.svgFonts)
-	for i, font := range resources.Fonts {
-		s.svgFonts[font.Name] = font.Data
-		resources.Fonts[i].Data = nil
-	}
 	return PageSVG{Index: index, Number: index + 1, ID: page.ID, Width: box.W, Height: box.H, SVG: buf.String(), Links: links, Fonts: resources.Fonts, Images: resources.Images, Annotations: annotations}, nil
 }
 
@@ -1282,26 +1293,21 @@ func (r *browserReaderAt) ReadAt(data []byte, offset int64) (int, error) {
 		if offset >= r.size {
 			return n, io.EOF
 		}
-		if time.Since(r.checked) >= 50*time.Millisecond {
+		r.mu.Lock()
+		check := r.checkpoint.Type() == platformTypeFunction && time.Since(r.checked) >= 50*time.Millisecond
+		if check {
+			r.checked = time.Now()
+		}
+		r.mu.Unlock()
+		if check {
 			if err := awaitExport(r.checkpoint); err != nil {
 				return n, err
 			}
-			r.checked = time.Now()
 		}
-		if len(r.data) == 0 || offset < r.offset || offset-r.offset >= int64(len(r.data)) {
-			r.offset = offset / (256 << 10) * (256 << 10)
-			size := int(min(int64(256<<10), r.size-r.offset))
-			if cap(r.data) < size {
-				r.data = make([]byte, size)
-			} else {
-				r.data = r.data[:size]
+		copied, err := r.readChunk(data, offset)
+		if err != nil {
+			return n, err
 		}
-			value := r.read.Invoke(float64(r.offset), size)
-			if platformCopyBytes(r.data, value) != size {
-				return n, io.ErrUnexpectedEOF
-			}
-		}
-		copied := copy(data, r.data[offset-r.offset:])
 		n += copied
 		offset += int64(copied)
 		data = data[copied:]
@@ -1309,6 +1315,31 @@ func (r *browserReaderAt) ReadAt(data []byte, offset int64) (int, error) {
 	return n, nil
 }
 
+// readChunk 串行读取和复用缓存块，仅保留完整读取的内容
+// 入参: data 目标缓冲, offset 文件内偏移
+// 返回: int 复制字节数, error 读取错误
+func (r *browserReaderAt) readChunk(data []byte, offset int64) (int, error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if len(r.data) == 0 || offset < r.offset || offset-r.offset >= int64(len(r.data)) {
+		start := offset / (256 << 10) * (256 << 10)
+		size := int(min(int64(256<<10), r.size-start))
+		buffer := r.data
+		r.data = nil
+		if cap(buffer) < size {
+			buffer = make([]byte, size)
+		} else {
+			buffer = buffer[:size]
+		}
+		value := r.read.Invoke(float64(start), size)
+		if platformCopyBytes(buffer, value) != size {
+			return 0, io.ErrUnexpectedEOF
+		}
+		r.offset, r.data = start, buffer
+	}
+	return copy(data, r.data[offset-r.offset:]), nil
+}
+
 // renderBackends 返回库提供的内置后端能力
 // 入参: args 浏览器参数
 // 返回: any 后端能力, error 错误信息
@@ -2440,7 +2471,7 @@ func (e *businessEngine) svgFontData(args []platformValue) (any, error) {
 }
 
 // renderPage 渲染OFD页面
-// 入参: args 页面索引、后端组合、DPI和光栅显示开关
+// 入参: args 页面索引、后端组合、DPI、光栅开关、已持有字体和图片、仅预览开关
 // 返回: any 页面SVG结果, error 错误信息
 func (e *businessEngine) renderPage(args []platformValue) (any, error) {
 	if e.currentSession == nil {
@@ -2457,6 +2488,13 @@ func (e *businessEngine) renderPage(args []platformValue) (any, error) {
 		dpi = args[2].Float()
 	}
 	raster := len(args) > 3 && args[3].Bool()
+	preview := len(args) > 6 && args[6].Bool()
+	known := make(map[string]bool)
+	for i := 4; i < min(len(args), 6); i++ {
+		for j := 0; j < args[i].Length(); j++ {
+			known[args[i].Index(j).String()] = true
+		}
+	}
 	if e.currentEditor != nil {
 		page, err := e.currentEditor.Page(args[0].Int())
 		if err != nil {
@@ -2466,25 +2504,31 @@ func (e *businessEngine) renderPage(args []platformValue) (any, error) {
 			return nil, err
 		}
 	}
-	page, err := e.currentSession.RenderPage(args[0].Int(), backend, dpi, raster)
+	page, err := e.currentSession.renderPage(args[0].Int(), backend, dpi, raster, preview, known)
 	if err != nil {
 		return nil, err
 	}
 	if e.currentEditor != nil && !reflect.DeepEqual(e.currentEditor.Backends(), e.currentSession.Renderer.Backends()) {
 		e.currentEditor.SetRenderBackends(e.currentSession.Renderer.Backends())
 	}
-	text, err := e.currentSession.PageText(args[0].Int())
+	text := &ofdgo.PageText{}
+	if !preview {
+		text, err = e.currentSession.PageText(args[0].Int())
 		if err != nil {
 			return nil, err
 		}
+	}
 	textData, err := json.Marshal(text)
 	if err != nil {
 		return nil, err
 	}
-	objects, err := e.editorObjects(args[0].Int(), text)
+	var objects []any
+	if !preview {
+		objects, err = e.editorObjects(args[0].Int(), text)
 		if err != nil {
 			return nil, err
 		}
+	}
 	links, err := e.linkResults(page.Links)
 	if err != nil {
 		return nil, err
@@ -2492,12 +2536,16 @@ func (e *businessEngine) renderPage(args []platformValue) (any, error) {
 	fonts := make([]any, len(page.Fonts))
 	for i, font := range page.Fonts {
 		fonts[i] = map[string]any{"name": font.Name, "weight": font.Weight, "style": font.Style}
+		if len(args) > 4 && !known[font.Name] {
+			fonts[i].(map[string]any)["data"] = bytesToJS(e.currentSession.svgFonts[font.Name])
+		}
 	}
 	annotations, err := json.Marshal(page.Annotations)
 	if err != nil {
 		return nil, err
 	}
 	return successResult(map[string]any{
+		"previewOnly": preview,
 		"annotations": string(annotations),
 		"index":       page.Index,
 		"number":      page.Number,
@@ -5502,7 +5550,7 @@ func (e *businessEngine) clearImport() {
 }
 
 // loadImport 加载待导入文件的索引，null参数清除待处理文件
-// 入参: args OFD字节数组或null
+// 入参: args 文档输入或null及可选凭据
 // 返回: any 文档列表、页数及签名提示, error 错误信息
 func (e *businessEngine) loadImport(args []platformValue) (any, error) {
 	e.clearImport()

internal/webui/webui_native.go

@@ -249,7 +249,7 @@ func (e *NativeEngine) Call(ctx context.Context, name string, args []any, emit f
 				font["data"] = worker.svgFonts[name]
 			}
 		}
-		if e.currentEditor != nil {
+		if e.currentEditor != nil && !(len(values) > 6 && values[6].Bool()) {
 			objects, textErr := e.renderObjects(operation, values[0].Int())
 			if textErr != nil {
 				return nativeFailure(textErr)

internal/webui/webui_wasm.go

@@ -221,8 +221,11 @@ func platformParseJSON(data []byte) map[string]any {
 	return result
 }
 
-// inputFromValue 读取浏览器二进制源
+// inputFromValue 读取浏览器随机输入或二进制数据
 func (e *businessEngine) inputFromValue(value platformValue) (*ofdgo.Input, error) {
+	if value.Type() == platformTypeObject && !value.IsNull() && value.Get("read").Type() == platformTypeFunction {
+		return ofdgo.NewInput(&browserReaderAt{read: value.Get("read"), size: int64(value.Get("size").Float())}, int64(value.Get("size").Float()))
+	}
 	data, err := e.bytesFromJS(value)
 	if err != nil {
 		return nil, err

ofdgo_image.go

@@ -320,16 +320,13 @@ func (r *Renderer) cachedImageResource(resPath string) (image.Image, error) {
 		}
 	}
 	resPath = cleanPackagePath(r.Reader.ResPath(resPath))
-	img, ok := r.imageCache.get(resPath)
-	if !ok {
-		var err error
-		img, err = r.readImageResource(resPath)
+	return r.imageCache.load(r.pageContext, resPath, func() (image.Image, int, error) {
+		img, err := r.readImageResource(resPath)
 		if err != nil {
-			return nil, err
+			return nil, 0, err
 		}
-		r.imageCache.put(resPath, img, baseimage.StorageCost(img, r.imageCache.limit))
-	}
-	return img, nil
+		return img, baseimage.StorageCost(img, r.imageCache.limit), nil
+	})
 }
 
 // decodeImageResource 读取或复用图片资源，按输出需要解码像素

ofdgo_render_cache.go

@@ -16,6 +16,8 @@ package ofdgo
 
 import (
 	"container/list"
+	"context"
+	"errors"
 	"image"
 	"reflect"
 	"sync"
@@ -29,6 +31,14 @@ type renderCache[K comparable, V any] struct {
 	limit, used int
 	entries     map[K]*list.Element
 	order       list.List
+	loading     map[K]*renderCacheLoad[V]
+}
+
+// renderCacheLoad 合并同一资源的并发加载，不持有已完成任务
+type renderCacheLoad[V any] struct {
+	done  chan struct{}
+	value V
+	err   error
 }
 
 // renderCacheEntry 保存缓存值及内存成本
@@ -79,6 +89,61 @@ func (c *renderCache[K, V]) put(key K, value V, cost int) {
 	c.used += cost
 }
 
+// load 复用缓存并合并并发请求，等待取消不影响正在读取的任务
+// 入参: ctx 当前任务上下文, key 缓存键, read 加载资源及其内存成本
+// 返回: V 缓存值, error 读取或取消错误
+func (c *renderCache[K, V]) load(ctx context.Context, key K, read func() (V, int, error)) (V, error) {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	var zero V
+	for {
+		if err := ctx.Err(); err != nil {
+			return zero, err
+		}
+		c.mu.Lock()
+		if item := c.entries[key]; item != nil {
+			c.order.MoveToFront(item)
+			value := item.Value.(renderCacheEntry[K, V]).value
+			c.mu.Unlock()
+			return value, nil
+		}
+		if pending := c.loading[key]; pending != nil {
+			c.mu.Unlock()
+			select {
+			case <-ctx.Done():
+				return zero, ctx.Err()
+			case <-pending.done:
+				if errors.Is(pending.err, context.Canceled) || errors.Is(pending.err, context.DeadlineExceeded) {
+					continue
+				}
+				return pending.value, pending.err
+			}
+		}
+		if c.loading == nil {
+			c.loading = make(map[K]*renderCacheLoad[V])
+		}
+		pending := &renderCacheLoad[V]{done: make(chan struct{}), err: errors.New("resource loading interrupted")}
+		c.loading[key] = pending
+		c.mu.Unlock()
+		defer func() {
+			c.mu.Lock()
+			delete(c.loading, key)
+			close(pending.done)
+			c.mu.Unlock()
+		}()
+		value, cost, err := read()
+		if err == nil {
+			err = ctx.Err()
+		}
+		pending.value, pending.err = value, err
+		if err == nil {
+			c.put(key, value, cost)
+		}
+		return value, err
+	}
+}
+
 // rasterCommandCost 按保留容量估算中立指令成本，不含临时后端路径及借用图片
 // 入参: command 绘制指令
 // 返回: int 字节成本

ofdgo_render_svg.go

@@ -50,6 +50,8 @@ type SVGResources struct {
 type PreviewOptions struct {
 	Raster  bool
 	Objects bool
+	// KnownResources 标识调用方仍持有的资源，返回引用但不重复返回数据
+	KnownResources map[string]bool
 }
 
 // RenderToSVGWithFonts 渲染为SVG并返回页面引用的字体资源，不在SVG中嵌入字体
@@ -92,7 +94,19 @@ func (r *Renderer) renderSVG(page *PageContent, writer io.Writer, mode SVGMode)
 // RenderPreview 生成统一SVG容器及独立资源，原生程序与WebUI使用相同绘制入口
 // 入参: page 页面内容, writer 输出流, options 显示方式
 // 返回: SVGResources 需由调用方映射地址的资源, error 错误信息
-func (r *Renderer) RenderPreview(page *PageContent, writer io.Writer, options PreviewOptions) (SVGResources, error) {
+func (r *Renderer) RenderPreview(page *PageContent, writer io.Writer, options PreviewOptions) (resources SVGResources, err error) {
+	defer func() {
+		for i := range resources.Fonts {
+			if options.KnownResources[resources.Fonts[i].Name] {
+				resources.Fonts[i].Data = nil
+			}
+		}
+		for i := range resources.Images {
+			if options.KnownResources[resources.Images[i].Name] {
+				resources.Images[i].Data = nil
+			}
+		}
+	}()
 	if !options.Raster {
 		if options.Objects {
 			return r.RenderToSVGWithObjects(page, writer)

ofdgo_render_text.go

@@ -40,6 +40,7 @@ type PositionedText struct {
 
 // glyphOutlineKey 区分字体、字形与毫米字号
 type glyphOutlineKey struct {
+	digest [32]byte
 	font   *PreparedFont
 	glyph  uint16
 	size   float64
@@ -279,21 +280,20 @@ func (r *Renderer) preparedMetrics(prepared *PreparedFont) (FontMetrics, error)
 		prepared.digest = r.fontDigest(prepared.Data)
 	}
 	key := prepared.digest
-	if metrics, ok := r.fontMetrics.get(key); ok {
-		return metrics, nil
-	}
+	return r.fontMetrics.load(r.pageContext, key, func() (FontMetrics, int, error) {
 		metrics, err := r.backends.Fonts.OpenFont(prepared.Data)
-	if err != nil {
-		return nil, err
-	}
-	r.fontMetrics.put(key, metrics, len(prepared.Data)*2+256)
-	return metrics, nil
+		return metrics, len(prepared.Data)*2 + 256, err
+	})
 }
 
 // preparedOutlines 批量提取缓存未命中的字形，保留原始编号顺序，不触发塑形
 // 入参: prepared 字体, metrics 度量, glyphs 字形编号, size 毫米字号
 // 返回: []GeometryPath 同序只读轮廓, error 能力或解析错误
 func (r *Renderer) preparedOutlines(prepared *PreparedFont, metrics FontMetrics, glyphs []uint16, size float64) ([]GeometryPath, error) {
+	key := glyphOutlineKey{digest: prepared.digest, size: size}
+	if key.digest == ([32]byte{}) {
+		key.font = prepared
+	}
 	result := make([]GeometryPath, len(glyphs))
 	var indices []int
 	missing := make([]uint16, 0)
@@ -304,7 +304,8 @@ func (r *Renderer) preparedOutlines(prepared *PreparedFont, metrics FontMetrics,
 				return nil, err
 			}
 		}
-		if path, ok := r.glyphOutlines.get(glyphOutlineKey{prepared, glyph, size}); ok {
+		key.glyph = glyph
+		if path, ok := r.glyphOutlines.get(key); ok {
 			result[i] = path
 			continue
 		}
@@ -360,7 +361,8 @@ func (r *Renderer) preparedOutlines(prepared *PreparedFont, metrics FontMetrics,
 		}
 	}
 	for i, path := range paths {
-		r.glyphOutlines.put(glyphOutlineKey{prepared, missing[i], size}, path, len(path)*96+128)
+		key.glyph = missing[i]
+		r.glyphOutlines.put(key, path, len(path)*96+128)
 	}
 	for i, index := range indices {
 		if index >= 0 {