diff --git a/assets/webui/ofdgo.js b/assets/webui/ofdgo.js
index a75b831..dcc7f29 100644
--- a/assets/webui/ofdgo.js
+++ b/assets/webui/ofdgo.js
@@ -2334,7 +2334,7 @@ async function refreshEditorPage(doc, index, openSeq, clearSelection = false) {
 			updateControls();
 			loadDocumentDetails(openSeq);
 			for (const page of doc.pages) {
-				observeFlowPage(pageShell(page.index), page.index);
+				observeFlowPage(pageShell(page.index));
 				const button = el.pageList.querySelector(`[data-page-index="${page.index}"]`);
 				observeThumbnail(button, page.index, openSeq);
 			}
@@ -3343,15 +3343,17 @@ async function openDocument(options = {}) {
 }
 
 async function loadDocumentDetails(openSeq) {
-	await waitForPaint();
-	if (openSeq !== state.openSeq) {
-		return;
-	}
 	try {
-		const info = await callWASM("ofdgoDocumentInfo");
-		if (openSeq === state.openSeq) {
-			Object.assign(state.doc, info, { detailsPending: false, detailsError: "" });
-			renderMeta();
+		while (openSeq === state.openSeq) {
+			await waitForPaint();
+			if (openSeq !== state.openSeq) return;
+			const info = await callWASM("ofdgoDocumentInfo", true);
+			if (openSeq !== state.openSeq) return;
+			if (!info.detailsPending) {
+				Object.assign(state.doc, info, { detailsPending: false, detailsError: "" });
+				renderMeta();
+				return;
+			}
 		}
 	} catch (err) {
 		if (openSeq === state.openSeq) {
@@ -3607,12 +3609,12 @@ function renderPageFlow() {
 
 		shell.append(surface, placeholder);
 		fragment.append(shell);
-		targets.push([shell, page.index]);
+		targets.push(shell);
 	}
 	el.svgHost.append(fragment);
 	layoutPages();
-	for (const [shell, index] of targets) {
-		observeFlowPage(shell, index);
+	for (const shell of targets) {
+		observeFlowPage(shell);
 	}
 	el.emptyState.hidden = true;
 	el.pageFrame.hidden = false;
@@ -3642,11 +3644,7 @@ function resetPageLoading() {
 	}
 }
 
-function observeFlowPage(shell, index) {
-	const openSeq = state.openSeq;
-	if (index < 4 && index !== state.pageIndex) {
-		renderFlowPage(index, { openSeq, priority: 3 });
-	}
+function observeFlowPage(shell) {
 	const observer = flowPageObserver();
 	if (observer) {
 		observer.observe(shell);
@@ -5152,14 +5150,7 @@ function observeThumbnail(button, index, openSeq = state.openSeq) {
 	if (observer) {
 		observer.observe(button);
 	}
-	if (index === state.pageIndex || index < 6) {
-		renderThumbnail(index, openSeq);
-		return;
-	}
-	if (observer) {
-		return;
-	}
-	if (index < 8) {
+	if (index === state.pageIndex || !observer && index < 8) {
 		renderThumbnail(index, openSeq);
 	}
 }
@@ -5271,7 +5262,7 @@ function renderMeta(keepDetails = false) {
 	renderMetaContent(el.attachmentList, [doc.attachments, doc.attachmentError], renderAttachments);
 	renderMetaContent(el.signatureList, [doc.signatures, doc.signatureError], renderSignatures);
 	renderMetaContent(el.docFontList, doc.fonts || [], renderDocumentFonts);
-	updateTextFonts(canvasEditor.selected, true);
+	refreshEditorFonts();
 	updateLocalFontButton();
 }
 
diff --git a/internal/webui/wasm.go b/internal/webui/wasm.go
index f3cfe94..6d1b794 100644
--- a/internal/webui/wasm.go
+++ b/internal/webui/wasm.go
@@ -293,13 +293,16 @@ func configureDocument(args []js.Value) (any, error) {
 	return currentSession.Summary(), nil
 }
 
-// documentInfo 获取首屏之后加载的字体统计和验签结果
+// documentInfo 获取字体统计和验签结果，首个参数为true时逐页扫描
 // 入参: args 浏览器参数
 // 返回: any 文档信息, error 错误信息
 func documentInfo(args []js.Value) (any, error) {
 	if currentSession == nil {
 		return nil, fmt.Errorf("ofd document is not opened")
 	}
+	if len(args) > 0 && args[0].Bool() && !currentSession.scanFontInfo() {
+		return map[string]bool{"detailsPending": true}, nil
+	}
 	return currentSession.Info(), nil
 }
 
@@ -2731,7 +2734,14 @@ func editDocument(args []js.Value) (any, error) {
 		return nil, err
 	}
 	editor.SetHistoryLimit(100)
-	return previewEditor(editor, currentSession.Renderer.RenderAnnotations)
+	if currentSession.fontFS != nil {
+		editor.SetFontFS(currentSession.fontFS)
+	}
+	currentEditor = editor
+	currentSession.editing = true
+	copiedObjects = nil
+	copiedStyle = nil
+	return editorSummary(), nil
 }
 
 // previewEditor 通过内存快照更新预览，不生成中间压缩包
diff --git a/internal/webui/webui.go b/internal/webui/webui.go
index 1f73eef..886d602 100644
--- a/internal/webui/webui.go
+++ b/internal/webui/webui.go
@@ -98,18 +98,22 @@ type SignatureStampInfo struct {
 
 // Session WebUI文档会话
 type Session struct {
-	Reader         *ofdgo.Reader
-	Renderer       *ofdgo.Renderer
-	fontFS         *ofdgo.FontFS
-	doc            *ofdgo.Document
-	pageCache      map[int]*ofdgo.PageContent
-	boxCache       map[int]ofdgo.Box
-	textCache      map[int]*ofdgo.PageText
-	svgFonts       map[string][]byte
-	signatures     []SignatureInfo
-	signatureError error
-	signaturesRead bool
-	editing        bool
+	Reader          *ofdgo.Reader
+	Renderer        *ofdgo.Renderer
+	fontFS          *ofdgo.FontFS
+	doc             *ofdgo.Document
+	pageCache       map[int]*ofdgo.PageContent
+	boxCache        map[int]ofdgo.Box
+	textCache       map[int]*ofdgo.PageText
+	svgFonts        map[string][]byte
+	fontScan        *ofdgo.FontInfoScanner
+	fontInfos       []FontInfo
+	fontsRead       bool
+	fontAnnotations bool
+	signatures      []SignatureInfo
+	signatureError  error
+	signaturesRead  bool
+	editing         bool
 }
 
 // DocumentInfo 文档信息
@@ -282,9 +286,44 @@ func (s *Session) SetFonts(fonts []FontFile) error {
 	}
 	clear(s.textCache)
 	clear(s.svgFonts)
+	s.resetFontInfo()
 	return nil
 }
 
+// resetFontInfo 清除字体统计及扫描状态，供字体或注解配置变更后重算
+func (s *Session) resetFontInfo() {
+	s.fontScan = nil
+	s.fontInfos = nil
+	s.fontsRead = false
+}
+
+// scanFontInfo 分步统计字体，每次最多处理一页，完成后保留当前会话的诊断
+// 返回: bool 是否完成
+func (s *Session) scanFontInfo() bool {
+	if s.fontAnnotations != s.Renderer.RenderAnnotations {
+		s.resetFontInfo()
+		s.fontAnnotations = s.Renderer.RenderAnnotations
+	}
+	if s.fontsRead {
+		return true
+	}
+	if s.fontScan == nil {
+		var err error
+		s.fontScan, err = s.Renderer.ScanFontInfos()
+		if err != nil {
+			s.fontsRead = true
+			return true
+		}
+	}
+	if s.fontScan.Next() {
+		return false
+	}
+	s.fontInfos, _ = s.fontScan.Infos()
+	s.fontsRead = true
+	s.fontScan = nil
+	return true
+}
+
 // PageText 获取指定页面文字，复用当前会话的文字索引
 // 入参: index 页面索引
 // 返回: *ofdgo.PageText 页面文字, error 错误信息
@@ -429,9 +468,9 @@ func (s *Session) Info() DocumentInfo {
 		}
 		info.Pages = append(info.Pages, pageInfo)
 	}
-	if fonts, err := s.Renderer.FontInfos(); err == nil {
-		info.Fonts = fonts
+	for !s.scanFontInfo() {
 	}
+	info.Fonts = s.fontInfos
 	info.FontCount = len(info.Fonts)
 	return info
 }
diff --git a/ofdgo_font_info.go b/ofdgo_font_info.go
index 7d6e0ce..7892bac 100644
--- a/ofdgo_font_info.go
+++ b/ofdgo_font_info.go
@@ -149,11 +149,61 @@ func (r *Reader) embeddedFontFace(of Font) (*FontFace, error) {
 // FontInfos 获取OFD字体诊断信息
 // 返回: []FontInfo 字体诊断列表, error 错误信息
 func (r *Renderer) FontInfos() ([]FontInfo, error) {
+	scanner, err := r.ScanFontInfos()
+	if err != nil {
+		return nil, err
+	}
+	for scanner.Next() {
+	}
+	return scanner.Infos()
+}
+
+// FontInfoScanner 逐页统计字体用量，不保留页面图元，扫描期间不得修改阅读器或渲染器配置
+type FontInfoScanner struct {
+	renderer *Renderer
+	doc      *Document
+	index    int
+	usage    map[string]int
+}
+
+// ScanFontInfos 创建分步字体诊断，页面读取失败的处理与FontInfos一致
+// 返回: *FontInfoScanner 字体诊断扫描器, error 错误信息
+func (r *Renderer) ScanFontInfos() (*FontInfoScanner, error) {
 	doc, err := r.fontInfoDocument()
 	if err != nil {
 		return nil, err
 	}
-	return r.fontInfos(doc, nil)
+	return &FontInfoScanner{renderer: r, doc: doc, usage: make(map[string]int)}, nil
+}
+
+// Next 统计下一页或模板的字体用量
+// 返回: bool 是否处理了页面，false表示扫描结束
+func (s *FontInfoScanner) Next() bool {
+	pages := len(s.doc.Pages.Page)
+	if s.index < pages {
+		if counts, err := s.renderer.readPageFontUsage(s.doc.Pages.Page[s.index]); err == nil {
+			for id, count := range counts {
+				s.usage[id] += count
+			}
+		}
+	} else if index := s.index - pages; index < len(s.doc.CommonData.TemplatePage) {
+		if page := s.renderer.loadTemplate(s.doc.CommonData.TemplatePage[index].ID); page != nil {
+			s.renderer.countPageFonts(page, s.usage)
+		}
+	} else {
+		return false
+	}
+	s.index++
+	return true
+}
+
+// Infos 获取扫描结束后的字体诊断，不返回未完成的用量统计
+// 返回: []FontInfo 字体诊断列表, error 错误信息
+func (s *FontInfoScanner) Infos() ([]FontInfo, error) {
+	if s.index < len(s.doc.Pages.Page)+len(s.doc.CommonData.TemplatePage) {
+		return nil, fmt.Errorf("font info scan is not complete")
+	}
+	return s.renderer.fontInfos(s.usage)
 }
 
 // FontInfosFromPages 从页面内容获取OFD字体诊断信息
@@ -164,10 +214,7 @@ func (r *Renderer) FontInfosFromPages(pages []*PageContent) ([]FontInfo, error)
 	if err != nil {
 		return nil, err
 	}
-	if pages == nil {
-		pages = []*PageContent{}
-	}
-	return r.fontInfos(doc, pages)
+	return r.fontInfos(r.fontUsage(doc, pages))
 }
 
 // fontInfoDocument 获取字体诊断文档结构
@@ -187,10 +234,9 @@ func (r *Renderer) fontInfoDocument() (*Document, error) {
 }
 
 // fontInfos 获取OFD字体诊断信息
-// 入参: doc 文档结构, pages 页面内容列表
+// 入参: usage 字体使用次数
 // 返回: []FontInfo 字体诊断列表, error 错误信息
-func (r *Renderer) fontInfos(doc *Document, pages []*PageContent) ([]FontInfo, error) {
-	usage := r.fontUsage(doc, pages)
+func (r *Renderer) fontInfos(usage map[string]int) ([]FontInfo, error) {
 	fonts, err := r.Reader.Fonts()
 	if err != nil {
 		return nil, err
@@ -271,23 +317,13 @@ func (r *Renderer) fontInfo(font Font) FontInfo {
 }
 
 // fontUsage 统计文档字体使用次数
-// 入参: doc 文档结构, pages 页面内容列表, nil表示读取文档页面
+// 入参: doc 文档结构, pages 页面内容列表
 // 返回: map[string]int 字体使用次数
 func (r *Renderer) fontUsage(doc *Document, pages []*PageContent) map[string]int {
 	usage := make(map[string]int)
-	if pages == nil {
-		for _, pageRef := range doc.Pages.Page {
-			if counts, err := r.readPageFontUsage(pageRef); err == nil {
-				for id, count := range counts {
-					usage[id] += count
-				}
-			}
-		}
-	} else {
-		for _, page := range pages {
-			if page != nil {
-				r.countPageFonts(page, usage)
-			}
+	for _, page := range pages {
+		if page != nil {
+			r.countPageFonts(page, usage)
 		}
 	}
 	for _, tpl := range doc.CommonData.TemplatePage {