feat(编辑压缩): 规范导入编辑，优化资源压缩

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/tdewolff/canvas v0.0.0-20260923214215-09804640d00c
 	github.com/xiaoqidun/j2kgo v0.0.0-20261011021706-cedb3037ff6e
 	github.com/xiaoqidun/jbig2 v1.1.4
-	github.com/xiaoqidun/pdfgo v0.0.0-20261011113302-5ef97798f3e9
+	github.com/xiaoqidun/pdfgo v0.0.0-20261011164142-f98f64ee48bb
 	golang.org/x/crypto v0.58.0
 	golang.org/x/image v0.47.0
 	golang.org/x/text v0.43.0

go.sum

@@ -62,8 +62,8 @@ github.com/xiaoqidun/j2kgo v0.0.0-20261011021706-cedb3037ff6e h1:OuRcvG5g5AieBN3
 github.com/xiaoqidun/j2kgo v0.0.0-20261011021706-cedb3037ff6e/go.mod h1:DCwAfuDzCDYqUiAlZ7BDwigTjaXw7o9L1FtEma/D1aA=
 github.com/xiaoqidun/jbig2 v1.1.4 h1:LF6J1si4JY+TszTh9+m4KAg9/ba0JjfXoGtQTQC2S8c=
 github.com/xiaoqidun/jbig2 v1.1.4/go.mod h1:9jromqVwMqlptUDEt6Yip8vqYA5I1YjhG7FgMl/Z2dA=
-github.com/xiaoqidun/pdfgo v0.0.0-20261011113302-5ef97798f3e9 h1:ET5BMHDQ18Tr8sMUX7K8tw3FYMtBnl6pBYLYy0OI550=
-github.com/xiaoqidun/pdfgo v0.0.0-20261011113302-5ef97798f3e9/go.mod h1:hkZn8gHOI94K0fE2ynbXaE8J5T0/jCvoTS/yroKgb+E=
+github.com/xiaoqidun/pdfgo v0.0.0-20261011164142-f98f64ee48bb h1:oxXcuj9fGKNLDYmSSiJjQXKkxSWQpmaNJwoF4SEtPZU=
+github.com/xiaoqidun/pdfgo v0.0.0-20261011164142-f98f64ee48bb/go.mod h1:hkZn8gHOI94K0fE2ynbXaE8J5T0/jCvoTS/yroKgb+E=
 github.com/xyproto/randomstring v1.0.5 h1:YtlWPoRdgMu3NZtP45drfy1GKoojuR7hmRcnhZqKjWU=
 github.com/xyproto/randomstring v1.0.5/go.mod h1:rgmS5DeNXLivK7YprL0pY+lTuhNQW3iGxZ18UQApw/E=
 github.com/yuin/goldmark v1.8.5 h1:r6N5afV5qj/5S4UTch8agZHJ8UxNCMwX7WjkkJam2NA=

ofdgo_compression_profiles.go

@@ -95,7 +95,7 @@ func compactResourceProfiles(ctx context.Context, reader *Reader, parts map[stri
 				return fmt.Errorf("file not found: %s", name)
 			}
 			var err error
-			data, err = reader.readFile(name)
+			data, err = reader.readFileViewContext(ctx, name)
 			if err != nil {
 				return err
 			}
@@ -110,15 +110,18 @@ func compactResourceProfiles(ctx context.Context, reader *Reader, parts map[stri
 				continue
 			}
 			for _, node := range group.children {
+				if err := ctx.Err(); err != nil {
+					return err
+				}
 				location := indexes[name][editorResourceID(node.attr("ID"))]
 				if !node.matchesOFD("ColorSpace") || location == "" {
 					continue
 				}
-				fragment, err := editorXMLAttribute(data, node, "Profile", "/"+location)
+				patch, err := editorXMLAttributePatch(data, node, "Profile", "/"+location)
 				if err != nil {
 					return err
 				}
-				patches = append(patches, editorXMLPatch{start: node.start, end: node.end, data: fragment})
+				patches = append(patches, patch)
 			}
 		}
 		updates[name] = editorPatchXML(data, patches)

ofdgo_compression_resources.go

@@ -72,10 +72,13 @@ func (e *Editor) compressResourceReferences(parts map[string][]byte, reader *Rea
 		names[name] = true
 	}
 	read := func(name string) ([]byte, error) {
+		if err := e.output.ctx.Err(); err != nil {
+			return nil, err
+		}
 		if data, ok := parts[name]; ok {
 			return data, nil
 		}
-		return reader.readFileView(name)
+		return reader.readFileViewContext(e.output.ctx, name)
 	}
 	actual := make(map[string]string)
 	for _, name := range slices.Sorted(maps.Keys(names)) {
@@ -108,13 +111,16 @@ func (e *Editor) compressResourceReferences(parts map[string][]byte, reader *Rea
 		if err != nil {
 			return err
 		}
-		root, err := parseEditorXML(data)
+		root, err := parseEditorXMLContext(e.output.ctx, data)
 		if err != nil {
 			return err
 		}
 		preserved := refs.versions[cleanPackagePath(name)]
 		for _, group := range root.children {
 			for _, node := range group.children {
+				if err := e.output.ctx.Err(); err != nil {
+					return err
+				}
 				field := ""
 				if group.name.Local == "Fonts" && node.name.Local == "Font" {
 					field = "FontFile"
@@ -189,6 +195,7 @@ func (e *Editor) compressResourceReferences(parts map[string][]byte, reader *Rea
 	if err := e.prepareOutputImages(imageKeys, load, imageResults, imageSources); err != nil {
 		return err
 	}
+	var fontCache editorSourceFontCache
 	for _, key := range ordered {
 		if refs.files[key] || files[resourceFile{key, "FontFile"}] && files[resourceFile{key, "MediaFile"}] {
 			continue
@@ -197,7 +204,7 @@ func (e *Editor) compressResourceReferences(parts map[string][]byte, reader *Rea
 			if !files[resourceFile{key, role}] {
 				continue
 			}
-			if err := editorProgress(e.OnWriteProgress).report("compress", e.output.completed, 0); err != nil {
+			if err := editorProgress(e.OnWriteProgress).withContext(e.output.ctx).report("compress", e.output.completed, 0); err != nil {
 				return err
 			}
 			source, prefetched := imageSources[key]
@@ -214,10 +221,13 @@ func (e *Editor) compressResourceReferences(parts map[string][]byte, reader *Rea
 				source.key.hash = sha256.Sum256(data)
 			}
 			if usage := fontUsage[key]; role == "FontFile" && usage != nil && !usage.unsafe {
-				candidate, err := e.backends.FontResources.SubsetSourceFont(data, FontUsage{Characters: slices.Sorted(maps.Keys(usage.chars)), Glyphs: slices.Sorted(maps.Keys(usage.glyphs))})
+				candidate, err := fontCache.subset(e.output.ctx, e.backends.FontResources, data, usage)
 				if err != nil {
 					return fmt.Errorf("subset font %s: %w", key, err)
 				}
+				if err := e.output.ctx.Err(); err != nil {
+					return err
+				}
 				if len(candidate) != 0 && len(candidate) < len(data) {
 					data = candidate
 					parts[actual[key]] = data
@@ -302,13 +312,16 @@ func (e *Editor) compressResourceReferences(parts map[string][]byte, reader *Rea
 		if err != nil {
 			return err
 		}
-		root, err := parseEditorXML(data)
+		root, err := parseEditorXMLContext(e.output.ctx, data)
 		if err != nil {
 			return err
 		}
 		var patches []editorXMLPatch
 		for _, group := range root.children {
 			for _, node := range group.children {
+				if err := e.output.ctx.Err(); err != nil {
+					return err
+				}
 				for _, field := range []string{"FontFile", "MediaFile"} {
 					file := node.child(field)
 					if file == nil {
@@ -319,7 +332,6 @@ func (e *Editor) compressResourceReferences(parts map[string][]byte, reader *Rea
 						return err
 					}
 					key := editorResourceLocation(name, root.attr("BaseLoc"), value)
-					fragment := data[node.start:node.end]
 					location := locations[key]
 					if first, ok := aliases[key]; ok {
 						location = locations[first]
@@ -327,23 +339,14 @@ func (e *Editor) compressResourceReferences(parts map[string][]byte, reader *Rea
 					if location != "" && location != actual[key] {
 						var escaped bytes.Buffer
 						xml.EscapeText(&escaped, []byte("/"+location))
-						patch := editorXMLContent(data, file, escaped.Bytes())
-						patch.start -= node.start
-						patch.end -= node.start
-						fragment = editorPatchXML(fragment, []editorXMLPatch{patch})
+						patches = append(patches, editorXMLContent(data, file, escaped.Bytes()))
 					}
 					if field == "MediaFile" && formats[key] != "" && node.attr("Format") != formats[key] {
-						parsed, err := parseEditorXML(fragment)
+						patch, err := editorXMLAttributePatch(data, node, "Format", formats[key])
 						if err != nil {
 							return err
 						}
-						fragment, err = editorXMLAttribute(fragment, parsed, "Format", formats[key])
-						if err != nil {
-							return err
-						}
-					}
-					if !bytes.Equal(fragment, data[node.start:node.end]) {
-						patches = append(patches, editorXMLPatch{start: node.start, end: node.end, data: fragment})
+						patches = append(patches, patch)
 					}
 				}
 			}

ofdgo_editor_annot_ops.go

@@ -188,7 +188,7 @@ func (e *Editor) PasteAnnotations(page int, selection *AnnotationSelection, dx,
 // 入参: page 页面索引, ids 注解标识, matrix 可逆页面变换
 // 返回: error 错误信息
 func (e *Editor) TransformAnnotations(page int, ids []string, matrix Matrix) error {
-	if _, ok := matrix.Invert(); !ok || !finite(matrix.a) || !finite(matrix.b) || !finite(matrix.c) || !finite(matrix.d) || !finite(matrix.e) || !finite(matrix.f) {
+	if _, ok := matrix.Invert(); !ok {
 		return fmt.Errorf("annotation transform must be finite and invertible")
 	}
 	return e.Transaction(func(edit *Editor) error {
@@ -210,6 +210,9 @@ func (e *Editor) TransformAnnotations(page int, ids []string, matrix Matrix) err
 				return err
 			}
 			bounds := matrix.TransformBox(box)
+			if !finite(bounds.X) || !finite(bounds.Y) || !finite(bounds.W) || !finite(bounds.H) || bounds.W < 0 || bounds.H < 0 {
+				return fmt.Errorf("annotation transform exceeds finite range")
+			}
 			path := ObjectPath{Annotation: id}
 			reader, _, _, members, err := edit.compositeScope(page, path)
 			if err != nil {

ofdgo_editor_attachment.go

@@ -84,7 +84,7 @@ func (e *Editor) AddAttachment(name string, data []byte) (string, error) {
 	}
 	node := doc.child("Attachments")
 	parts := map[string][]byte{file: bytes.Clone(data)}
-	if base.document.Attachments.Path != "" {
+	if strings.TrimSpace(base.document.Attachments.Path) != "" {
 		name := base.reader.ResPath(base.document.Attachments.Path)
 		existing, err := base.reader.readFile(name)
 		if err != nil {
@@ -203,7 +203,7 @@ func (e *Editor) ReplaceAttachment(id string, data []byte) error {
 	return nil
 }
 
-// DeleteAttachment 删除附件声明，保存时清理可确认无引用的内容，支持撤销和重做
+// DeleteAttachment 删除附件声明，输出时清理相关动作及可确认无引用的内容，支持撤销和重做
 // 入参: id 附件标识
 // 返回: error 附件结构或提交错误
 func (e *Editor) DeleteAttachment(id string) error {
@@ -270,6 +270,14 @@ func (e *Editor) editAttachment(id string, change func([]byte, *editorXML, map[s
 	if err := e.commitAnnotationParts(base, parts); err != nil {
 		return err
 	}
+	if len(updated) == 0 {
+		removed := maps.Clone(base.removedAttachments)
+		if removed == nil {
+			removed = make(map[string]bool)
+		}
+		removed[id] = true
+		e.source.removedAttachments = removed
+	}
 	if file := node.child("FileLoc"); file != nil {
 		location := strings.TrimSpace(editorImportText(fragment, file))
 		if location != "" {

ofdgo_editor_composite.go

@@ -653,7 +653,8 @@ func (e *Editor) measureCompositeMembers(renderer *Renderer, nodes []*editorComp
 		if transform && node.object.Type == "ImageObject" && bounds.Bounds.W > 0 && bounds.Bounds.H > 0 {
 			clips := node.object.ImageObject.Clips
 			_, capability.CropImage = node.matrix(clips.usesObjectMatrix()).Invert()
-			capability.FitImage = capability.CropImage && axisAlignedMatrix(NewMatrix(node.object.ImageObject.CTM))
+			_, fitErr := imageFitBasis(node.object.ImageObject.CTM)
+			capability.FitImage = capability.CropImage && fitErr == nil
 			capability.ResetCrop = node.states[editorObjectID(node.object)].crop != nil
 		}
 		_, ctm := editorGeometry(node.object)

ofdgo_editor_composite_image.go

@@ -108,7 +108,7 @@ func (e *Editor) ResetImageCrop(page int, id string) error {
 	return e.updateObjectOrigins(page, []GraphicObject{node.object}, true, map[string]*editorObjectOrigin{id: next})
 }
 
-// FitCompositeImage 按原像素比例适应或填充内部图片框，保留原始裁剪和蒙版
+// FitCompositeImage 按原像素比例适应或填充内部图片框，保留轴方向、原始裁剪和蒙版
 // 入参: page 页面索引, path 父路径, index 图片序号, mode 为contain或cover
 // 返回: error 错误信息
 func (e *Editor) FitCompositeImage(page int, path ObjectPath, index int, mode string) error {
@@ -117,6 +117,14 @@ func (e *Editor) FitCompositeImage(page int, path ObjectPath, index int, mode st
 		if !members[0].Capabilities.FitImage {
 			return fmt.Errorf("composite image fitting is not supported")
 		}
+		before, changed := node.data, node.changed
+		id := editorObjectID(node.object)
+		state := node.states[id]
+		defer func() {
+			if bytes.Equal(before, node.data) && reflect.DeepEqual(state, node.states[id]) {
+				node.changed = changed
+			}
+		}()
 		if err := resetCompositeImageCrop(node); err != nil {
 			return err
 		}
@@ -143,7 +151,10 @@ func (e *Editor) FitCompositeImage(page int, path ObjectPath, index int, mode st
 			frame = TranslationMatrix(box.X, box.Y).Multiply(node.parent)
 		}
 		clips := object.ImageObject.Clips
-		inverse, _ := node.matrix(clips.usesObjectMatrix()).Invert()
+		inverse, ok := node.matrix(clips.usesObjectMatrix()).Invert()
+		if !ok {
+			return fmt.Errorf("fitted image transform is not invertible")
+		}
 		return appendCompositeClip(node, shape, inverse.Multiply(frame), true)
 	})
 }
@@ -174,6 +185,11 @@ func (n *editorCompositeNode) matrix(transform bool) Matrix {
 // 入参: node 对象节点, shape 裁剪路径, matrix 路径到裁剪坐标的变换, track 是否记录还原序号
 // 返回: error 错误信息
 func appendCompositeClip(node *editorCompositeNode, shape PathObject, matrix Matrix, track bool) error {
+	for _, value := range matrix.Values() {
+		if !finite(value) {
+			return fmt.Errorf("clip transform exceeds finite range")
+		}
+	}
 	clip := Clip{Area: []ClipArea{{CTM: matrix.String(), Path: []PathObject{shape}}}}
 	if clips := *editorObjectClips(&node.object); clips != nil && slices.ContainsFunc(clips.Clip, func(previous Clip) bool { return reflect.DeepEqual(previous, clip) }) {
 		return nil

ofdgo_editor_composite_ops.go

@@ -254,6 +254,9 @@ func (e *Editor) copyCompositeNodes(renderer *Renderer, nodes []*editorComposite
 // 入参: object 修改后的对象
 // 返回: error 错误信息
 func (n *editorCompositeNode) update(object GraphicObject) error {
+	if err := validateEditorGeometry(object); err != nil {
+		return err
+	}
 	data, err := editorXMLObject(n.data, n.node, n.object, object)
 	if err != nil || bytes.Equal(data, n.data) {
 		return err

ofdgo_editor_font.go

@@ -16,7 +16,9 @@ package ofdgo
 
 import (
 	"bytes"
+	"context"
 	"crypto/sha256"
+	"encoding/binary"
 	"fmt"
 	"maps"
 	"slices"
@@ -38,6 +40,56 @@ type editorFontSubset struct {
 	mapped bool
 }
 
+// editorSourceFontKey 区分原字体内容及完整用字集合
+type editorSourceFontKey struct {
+	source [32]byte
+	usage  [32]byte
+}
+
+// editorSourceFontCache 在单次资源处理中复用裁剪结果，空值表示无体积收益
+type editorSourceFontCache map[editorSourceFontKey][]byte
+
+// subset 按原字体和用字复用安全子集，不缓存错误、取消结果或原始字体
+// 入参: ctx 取消上下文, backend 字体资源后端, data 原字体, usage 用字记录
+// 返回: []byte 更小的字体子集，无收益时为nil, error 裁剪或取消错误
+func (c *editorSourceFontCache) subset(ctx context.Context, backend FontResourceBackend, data []byte, usage *editorFontUsage) ([]byte, error) {
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+	if usage == nil || usage.unsafe || backend == nil {
+		return nil, nil
+	}
+	characters, glyphs := slices.Sorted(maps.Keys(usage.chars)), slices.Sorted(maps.Keys(usage.glyphs))
+	encoded := make([]byte, 0, 8+4*len(characters)+2*len(glyphs))
+	encoded = binary.LittleEndian.AppendUint32(encoded, uint32(len(characters)))
+	for _, char := range characters {
+		encoded = binary.LittleEndian.AppendUint32(encoded, uint32(char))
+	}
+	encoded = binary.LittleEndian.AppendUint32(encoded, uint32(len(glyphs)))
+	for _, glyph := range glyphs {
+		encoded = binary.LittleEndian.AppendUint16(encoded, glyph)
+	}
+	key := editorSourceFontKey{source: sha256.Sum256(data), usage: sha256.Sum256(encoded)}
+	if result, ok := (*c)[key]; ok {
+		return result, ctx.Err()
+	}
+	result, err := backend.SubsetSourceFont(data, FontUsage{Characters: characters, Glyphs: glyphs})
+	if err != nil {
+		return nil, err
+	}
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+	if len(result) == 0 || len(result) >= len(data) {
+		result = nil
+	}
+	if *c == nil {
+		*c = make(editorSourceFontCache)
+	}
+	(*c)[key] = result
+	return result, nil
+}
+
 // AddFont 注册OpenType字体，集合字体按索引提取，重复资源复用标识，引用后写入文档
 // 入参: file 字体文件, index 集合内字体索引，单字体为0
 // 返回: string 字体资源标识, error 错误信息

ofdgo_editor_import.go

@@ -43,24 +43,29 @@ type editorPageImport struct {
 	doc           *Document
 	directory     string
 	target        *Reader
-	paths         map[string]string
+	xmlPaths      map[string]string
+	dataPaths     map[string]string
 	templatePaths map[string]string
 	evidence      map[string]string
 	resourceXML   []byte
 	pageParts     []byte
 	documentXML   []byte
 	documentRoot  *editorXML
+	docRefs       map[string]map[string]*editorXML
 	maximum       int
 	ids           map[string]string
 	pages         map[string]bool
 	files         map[string][]byte
 	resources     map[string]editorImportEntry
+	resourceFiles map[string]bool
 	used          map[string][]byte
 	templates     map[string]TemplatePage
 	templateParts map[string][]byte
 	defaultCS     string
 	attachments   map[string][]byte
+	attachmentMap map[string]editorImportEntry
 	attachmentIDs map[string]bool
+	bookmarks     map[string]Dest
 	signatureIDs  *signatureIDSequence
 	copyPage      bool
 	strictLinks   bool
@@ -483,9 +488,15 @@ func (e *Editor) prepareImport(ctx context.Context, source *Reader, doc *Documen
 		}
 	}
 	m := &editorPageImport{ctx: ctx, reader: source, doc: doc, directory: e.packageDirectory(), target: base.reader, maximum: maximum, copyPage: copyPage, progress: progress,
-		paths: make(map[string]string), evidence: make(map[string]string), ids: make(map[string]string), pages: make(map[string]bool, len(selected)),
+		xmlPaths: make(map[string]string), dataPaths: make(map[string]string), evidence: make(map[string]string), ids: make(map[string]string), pages: make(map[string]bool, len(selected)),
 		files: make(map[string][]byte), resources: make(map[string]editorImportEntry), used: make(map[string][]byte),
-		templates: make(map[string]TemplatePage), templateParts: make(map[string][]byte), attachments: make(map[string][]byte)}
+		templates: make(map[string]TemplatePage), templateParts: make(map[string][]byte), attachments: make(map[string][]byte), bookmarks: make(map[string]Dest, len(doc.Bookmarks.Bookmark))}
+	for _, bookmark := range doc.Bookmarks.Bookmark {
+		if err := ctx.Err(); err != nil {
+			return nil, nil, err
+		}
+		m.bookmarks[bookmark.Name] = bookmark.Dest
+	}
 	for id, value := range selected {
 		m.pages[editorImportKey(id)] = value
 	}
@@ -516,7 +527,7 @@ func (e *Editor) prepareImport(ctx context.Context, source *Reader, doc *Documen
 		m.templates[editorImportKey(template.ID)] = template
 	}
 	if doc.CommonData.DefaultCS != 0 {
-		m.defaultCS, err = m.reference(strconv.Itoa(doc.CommonData.DefaultCS))
+		m.defaultCS, err = m.resource(strconv.Itoa(doc.CommonData.DefaultCS), "ColorSpace")
 		if err != nil {
 			return nil, nil, err
 		}
@@ -556,7 +567,7 @@ func (m *editorPageImport) encodeResources() error {
 		return nil
 	}
 	var err error
-	m.resourceXML, err = editorXMLContainer("Res", nil, content)
+	m.resourceXML, err = editorXMLContainer("Res", ofdAttrs{{Name: xml.Name{Local: "BaseLoc"}, Value: "."}}, content)
 	return err
 }
 
@@ -588,13 +599,12 @@ func (m *editorPageImport) outlines() ([]byte, error) {
 	if root == nil {
 		return nil, nil
 	}
-	bookmarks := make(map[string]Dest, len(m.doc.Bookmarks.Bookmark))
-	for _, bookmark := range m.doc.Bookmarks.Bookmark {
-		bookmarks[bookmark.Name] = bookmark.Dest
-	}
 	var patches []editorXMLPatch
 	var keep func(*editorXML) (bool, error)
 	keep = func(node *editorXML) (bool, error) {
+		if err := m.ctx.Err(); err != nil {
+			return false, err
+		}
 		start, selected := len(patches), false
 		if actions := node.child("Actions"); actions != nil {
 			var value struct {
@@ -605,7 +615,7 @@ func (m *editorPageImport) outlines() ([]byte, error) {
 			}
 			for _, action := range value.Action {
 				if action.Goto != nil {
-					if dest := gotoDest(action.Goto, bookmarks); dest != nil && m.pages[editorImportKey(dest.PageID)] {
+					if dest := gotoDest(action.Goto, m.bookmarks); dest != nil && m.pages[editorImportKey(dest.PageID)] {
 						selected = true
 					}
 				}
@@ -639,6 +649,9 @@ func (m *editorPageImport) outlines() ([]byte, error) {
 	}
 	var validate func(*editorXML) error
 	validate = func(node *editorXML) error {
+		if err := m.ctx.Err(); err != nil {
+			return err
+		}
 		for _, attr := range node.attrs {
 			if attr.Name.Space == "" || attr.Name.Space == "xmlns" {
 				continue
@@ -765,10 +778,17 @@ func (m *editorPageImport) id(value string) string {
 	return id
 }
 
-// resourceIndex 登记资源定义，按引用延迟复制资源内容
+// resourceIndex 每个索引只登记一次，拒绝重复资源标识，按引用延迟复制资源内容
 // 入参: name 资源索引路径
 // 返回: error 错误信息
 func (m *editorPageImport) resourceIndex(name string) error {
+	if err := m.ctx.Err(); err != nil {
+		return err
+	}
+	name = cleanPackagePath(name)
+	if m.resourceFiles[name] {
+		return nil
+	}
 	data, err := m.readFile(name)
 	if err != nil {
 		return err
@@ -780,15 +800,54 @@ func (m *editorPageImport) resourceIndex(name string) error {
 	if root.name.Local != "Res" {
 		return fmt.Errorf("invalid resource index %q", name)
 	}
+	entries := make(map[string]editorImportEntry)
 	for _, group := range root.children {
 		for _, node := range group.children {
-			m.resources[editorImportKey(node.attr("ID"))] = editorImportEntry{name: name, base: root.attr("BaseLoc"), group: group.name.Local, data: data, node: node}
+			if err := m.ctx.Err(); err != nil {
+				return err
+			}
+			id := editorImportKey(node.attr("ID"))
+			if _, exists := entries[id]; exists {
+				return fmt.Errorf("duplicate resource ID %q in %s", id, name)
+			}
+			if _, exists := m.resources[id]; exists {
+				return fmt.Errorf("duplicate resource ID %q in %s", id, name)
+			}
+			entries[id] = editorImportEntry{name: name, base: root.attr("BaseLoc"), group: group.name.Local, data: data, node: node}
 		}
 	}
+	maps.Copy(m.resources, entries)
+	if m.resourceFiles == nil {
+		m.resourceFiles = make(map[string]bool)
+	}
+	m.resourceFiles[name] = true
 	return nil
 }
 
-// reference 复制被引用的资源及其传递依赖
+// resource 按引用用途校验资源类型并迁移，避免生成悬空或类型不符的引用
+// 入参: value 来源资源标识, kind 资源类型或多媒体用途，空值仅检查资源是否存在
+// 返回: string 新标识, error 资源缺失、类型或迁移错误
+func (m *editorPageImport) resource(value, kind string) (string, error) {
+	if err := m.ctx.Err(); err != nil {
+		return "", err
+	}
+	entry, exists := m.resources[editorImportKey(value)]
+	if !exists {
+		return "", fmt.Errorf("resource %q not found", value)
+	}
+	if kind != "" {
+		expected, media := kind, ""
+		if kind == "Image" || kind == "Audio" || kind == "Video" {
+			kind, media = "MultiMedia", kind
+		}
+		if entry.group != kind+"s" || entry.node == nil || !entry.node.matchesOFD(kind) || media != "" && entry.node.attr("Type") != media {
+			return "", fmt.Errorf("invalid resource type for %q: expected %s", value, expected)
+		}
+	}
+	return m.reference(value)
+}
+
+// reference 复制被引用的资源及其传递依赖，拒绝循环依赖
 // 入参: value 来源资源标识
 // 返回: string 新标识, error 错误信息
 func (m *editorPageImport) reference(value string) (string, error) {
@@ -802,7 +861,9 @@ func (m *editorPageImport) reference(value string) (string, error) {
 		}
 	}
 	if entry, ok := m.resources[key]; ok {
-		if _, seen := m.used[key]; !seen {
+		if data, seen := m.used[key]; seen && data == nil {
+			return "", fmt.Errorf("cyclic resource reference %q", value)
+		} else if !seen {
 			m.used[key] = nil
 			data, err := m.encode(entry, entry.node)
 			if err != nil {
@@ -832,29 +893,52 @@ func (m *editorPageImport) reference(value string) (string, error) {
 // 入参: group 父节点名称, kind 引用节点名称, source 原标识, id 新标识, loc 新路径
 // 返回: []byte 引用XML, error 错误信息
 func (m *editorPageImport) documentReference(group, kind, source, id, loc string) ([]byte, error) {
-	if parent := m.documentRoot.child(group); parent != nil {
-		for _, node := range parent.children {
-			if node.name.Local != kind || editorImportKey(node.attr("ID")) != editorImportKey(source) {
-				continue
-			}
-			data, err := editorXMLStandalone(m.documentXML[node.start:node.end], node)
-			if err != nil {
-				return nil, err
-			}
-			for _, attr := range [][2]string{{"ID", id}, {"BaseLoc", loc}} {
-				root, err := parseEditorXMLContext(m.ctx, data)
-				if err != nil {
-					return nil, err
-				}
-				data, err = editorXMLAttribute(data, root, attr[0], attr[1])
-				if err != nil {
-					return nil, err
-				}
-			}
-			return data, nil
-		}
+	if err := m.ctx.Err(); err != nil {
+		return nil, err
 	}
-	return nil, fmt.Errorf("missing %s reference %q", kind, source)
+	nodes := m.docRefs[kind]
+	if nodes == nil {
+		nodes = make(map[string]*editorXML)
+		if parent := m.documentRoot.child(group); parent != nil {
+			for _, node := range parent.children {
+				if err := m.ctx.Err(); err != nil {
+					return nil, err
+				}
+				if !node.matchesOFD(kind) {
+					continue
+				}
+				key := editorImportKey(node.attr("ID"))
+				if nodes[key] != nil {
+					return nil, fmt.Errorf("duplicate %s reference %q", kind, key)
+				}
+				nodes[key] = node
+			}
+		}
+		if m.docRefs == nil {
+			m.docRefs = make(map[string]map[string]*editorXML)
+		}
+		m.docRefs[kind] = nodes
+	}
+	node := nodes[editorImportKey(source)]
+	if node == nil {
+		return nil, fmt.Errorf("missing %s reference %q", kind, source)
+	}
+	data, err := editorXMLStandalone(m.documentXML[node.start:node.end], node)
+	if err != nil {
+		return nil, err
+	}
+	for _, attr := range [][2]string{{"ID", id}, {"BaseLoc", loc}} {
+		root, err := parseEditorXMLContext(m.ctx, data)
+		if err != nil {
+			return nil, err
+		}
+		patch, err := editorXMLAttributePatch(data, root, attr[0], attr[1])
+		if err != nil {
+			return nil, err
+		}
+		data = editorPatchXML(data, []editorXMLPatch{patch})
+	}
+	return data, nil
 }
 
 // resolve 按所在XML和资源基准目录解析包内路径
@@ -871,11 +955,11 @@ func (m *editorPageImport) resolve(name, base, value string) (string, error) {
 	return "", fmt.Errorf("import reference %q in %s not found", value, name)
 }
 
-// copyData 复制二进制资源或签名引用原文，凭据与当前引用使用独立映射
+// copyData 复制原始数据，资源内容、签名凭据与重写XML使用独立路径映射
 // 入参: name 来源路径, relative 文档内候选路径, evidence 是否原始签名凭据
 // 返回: string 新路径, error 错误信息
 func (m *editorPageImport) copyData(name, relative string, evidence bool) (string, error) {
-	paths := m.paths
+	paths := m.dataPaths
 	if evidence {
 		paths = m.evidence
 		relative = path.Join("Signs", "Signed", path.Base(name))
@@ -900,7 +984,7 @@ func (m *editorPageImport) copyData(name, relative string, evidence bool) (strin
 // 入参: name 来源路径, candidate 目标候选路径, template 是否按模板页复制
 // 返回: string 新路径, error 错误信息
 func (m *editorPageImport) copyXML(name, candidate string, template bool) (string, error) {
-	paths := m.paths
+	paths := m.xmlPaths
 	if template {
 		if m.templatePaths == nil {
 			m.templatePaths = make(map[string]string)
@@ -1007,11 +1091,7 @@ func (m *editorPageImport) encode(entry editorImportEntry, node *editorXML) ([]b
 			if err := xml.Unmarshal(entry.data[gotoNode.start:gotoNode.end], &action); err != nil {
 				return nil, err
 			}
-			bookmarks := make(map[string]Dest)
-			for _, bookmark := range m.doc.Bookmarks.Bookmark {
-				bookmarks[bookmark.Name] = bookmark.Dest
-			}
-			if dest := gotoDest(&action, bookmarks); !m.copyPage && (dest == nil || !m.pages[editorImportKey(dest.PageID)]) {
+			if dest := gotoDest(&action, m.bookmarks); !m.copyPage && (dest == nil || !m.pages[editorImportKey(dest.PageID)]) {
 				if m.strictLinks {
 					return nil, fmt.Errorf("object link targets a page outside the imported selection")
 				}
@@ -1050,7 +1130,31 @@ func (m *editorPageImport) encode(entry editorImportEntry, node *editorXML) ([]b
 			} else if id := m.ids[editorImportKey(value)]; id != "" {
 				value = id
 			}
-		case "Font", "ResourceID", "Substitution", "ImageMask", "Relative", "DrawParam", "ColorSpace", "Thumbnail", "TemplateID", "PageRef", "RefId":
+		case "Font", "DrawParam", "ColorSpace":
+			value, err = m.resource(value, key)
+		case "Relative":
+			value, err = m.resource(value, "DrawParam")
+		case "Substitution", "ImageMask", "Thumbnail":
+			value, err = m.resource(value, "Image")
+		case "ResourceID":
+			kind := ""
+			switch name {
+			case "CompositeObject":
+				kind = "CompositeGraphicUnit"
+			case "ImageObject":
+				kind = "Image"
+			case "Sound":
+				kind = "Audio"
+			case "Movie":
+				kind = "Video"
+			}
+			value, err = m.resource(value, kind)
+		case "TemplateID":
+			if _, exists := m.templates[editorImportKey(value)]; !exists {
+				return nil, fmt.Errorf("template %q not found", value)
+			}
+			value, err = m.reference(value)
+		case "PageRef", "RefId":
 			value, err = m.reference(value)
 		case "BaseLoc", "FileRef":
 			loc, resolveErr := m.resolve(entry.name, "", value)
@@ -1147,11 +1251,7 @@ func (m *editorPageImport) encode(entry editorImportEntry, node *editorXML) ([]b
 			continue
 		}
 		if name == "Goto" && child.name.Local == "Bookmark" {
-			for _, bookmark := range m.doc.Bookmarks.Bookmark {
-				if bookmark.Name != child.attr("Name") {
-					continue
-				}
-				dest := bookmark.Dest
+			if dest, ok := m.bookmarks[child.attr("Name")]; ok {
 				encoded, err := xml.Marshal(dest)
 				if err != nil {
 					return nil, err
@@ -1174,6 +1274,9 @@ func (m *editorPageImport) encode(entry editorImportEntry, node *editorXML) ([]b
 		}
 		content = append(content, encoded...)
 	}
+	if name == "Actions" && len(content) == 0 {
+		return nil, nil
+	}
 	if len(node.children) == 0 {
 		value := editorImportText(entry.data, node)
 		var err error
@@ -1216,8 +1319,8 @@ func (m *editorPageImport) encode(entry editorImportEntry, node *editorXML) ([]b
 				candidate := path.Join(m.directory, "Annotations", "Page_"+m.id(node.parent.attr("PageID"))+".xml")
 				value, err = m.copyXML(loc, candidate, false)
 			}
-		case "Font", "Substitution", "Thumbnail":
-			value, err = m.reference(strings.TrimSpace(value))
+		case "Substitution", "Thumbnail":
+			value, err = m.resource(strings.TrimSpace(value), "Image")
 		}
 		if err != nil {
 			return nil, err
@@ -1265,39 +1368,58 @@ func (m *editorPageImport) annotations() ([]byte, error) {
 // 入参: id 来源附件标识
 // 返回: string 新标识, error 错误信息
 func (m *editorPageImport) attachment(id string) (string, error) {
+	if err := m.ctx.Err(); err != nil {
+		return "", err
+	}
 	if m.copyPage {
 		return id, nil
 	}
 	if _, exists := m.attachments[id]; exists {
 		return m.attachmentID(id)
 	}
-	name := m.reader.documentRoot
-	if m.doc.Attachments.Path != "" {
-		name = m.reader.ResPath(m.doc.Attachments.Path)
-	}
-	data, err := m.readFile(name)
-	if err != nil {
-		return "", err
-	}
-	root, err := parseEditorXMLContext(m.ctx, data)
-	if err != nil {
-		return "", err
-	}
-	if m.doc.Attachments.Path == "" {
-		root = root.child("Attachments")
-	}
-	if root != nil {
-		for _, node := range root.children {
-			if node.name.Local == "Attachment" && node.attr("ID") == id {
-				m.attachments[id], err = m.encode(editorImportEntry{name: name, data: data}, node)
-				if err != nil {
-					return "", err
-				}
-				return m.attachmentID(id)
+	if m.attachmentMap == nil {
+		name, data := m.reader.documentRoot, m.documentXML
+		root := m.documentRoot.child("Attachments")
+		if location := strings.TrimSpace(m.doc.Attachments.Path); location != "" {
+			name = m.reader.ResPath(location)
+			var err error
+			data, err = m.readFile(name)
+			if err != nil {
+				return "", err
+			}
+			root, err = parseEditorXMLContext(m.ctx, data)
+			if err != nil {
+				return "", err
 			}
 		}
+		entries := make(map[string]editorImportEntry)
+		if root != nil {
+			for _, node := range root.children {
+				if err := m.ctx.Err(); err != nil {
+					return "", err
+				}
+				if !node.matchesOFD("Attachment") {
+					continue
+				}
+				key := node.attr("ID")
+				if _, exists := entries[key]; exists {
+					return "", fmt.Errorf("duplicate attachment ID: %s", key)
+				}
+				entries[key] = editorImportEntry{name: name, data: data, node: node}
+			}
+		}
+		m.attachmentMap = entries
 	}
-	return "", fmt.Errorf("attachment %q not found", id)
+	entry, exists := m.attachmentMap[id]
+	if !exists {
+		return "", fmt.Errorf("attachment %q not found", id)
+	}
+	data, err := m.encode(entry, entry.node)
+	if err != nil {
+		return "", err
+	}
+	m.attachments[id] = data
+	return m.attachmentID(id)
 }
 
 // attachmentID 为来源附件分配独立的文本标识，避免与数值型资源标识混淆
@@ -1313,10 +1435,17 @@ func (m *editorPageImport) attachmentID(id string) (string, error) {
 		if err != nil {
 			return "", err
 		}
-		m.attachmentIDs = make(map[string]bool, len(attachments))
+		used := make(map[string]bool, len(attachments))
 		for _, attachment := range attachments {
-			m.attachmentIDs[attachment.ID] = true
+			if err := m.ctx.Err(); err != nil {
+				return "", err
+			}
+			if used[attachment.ID] {
+				return "", fmt.Errorf("duplicate attachment ID: %s", attachment.ID)
+			}
+			used[attachment.ID] = true
 		}
+		m.attachmentIDs = used
 	}
 	mapped, maximum := nextAttachmentID(m.attachmentIDs, m.maximum)
 	m.maximum, m.ids[key] = maximum, mapped
@@ -1353,15 +1482,11 @@ func (m *editorPageImport) signatureID(source, kind, id string) (string, error)
 			sequence.observe(list.MaxSignID)
 			for _, ref := range list.List {
 				sequence.observe(ref.ID)
-				data, err := m.target.readFileViewContext(m.ctx, signatureRefPath(name, ref.BaseLoc))
+				stamps, err := m.signatureStamps(m.target, signatureRefPath(name, ref.BaseLoc))
 				if err != nil {
 					return "", err
 				}
-				file, err := parseSignatureFile(data)
-				if err != nil {
-					return "", err
-				}
-				for _, stamp := range file.SignedInfo.StampAnnot {
+				for _, stamp := range stamps {
 					sequence.observe(stamp.ID)
 				}
 			}
@@ -1376,6 +1501,46 @@ func (m *editorPageImport) signatureID(source, kind, id string) (string, error)
 	return mapped, nil
 }
 
+// signatureStamps 流式读取签章位置，跳过本次迁移无需解析的摘要和提供者信息
+// 入参: reader 来源或目标阅读器, name 签名文件路径
+// 返回: []SignatureStamp 签章位置, error 读取、解析或取消错误
+func (m *editorPageImport) signatureStamps(reader *Reader, name string) ([]SignatureStamp, error) {
+	input, err := reader.openFile(name)
+	if err != nil {
+		return nil, err
+	}
+	defer input.Close()
+	var file struct {
+		XMLName xml.Name         `xml:"Signature"`
+		Stamps  []SignatureStamp `xml:"SignedInfo>StampAnnot"`
+	}
+	progress := m.progress.withContext(m.ctx)
+	decoder := xml.NewDecoder(&editorProgressReader{Reader: input, progress: progress, stage: "resources"})
+	if err := decoder.Decode(&file); err != nil {
+		return nil, err
+	}
+	for {
+		if err := m.ctx.Err(); err != nil {
+			return nil, err
+		}
+		token, err := decoder.Token()
+		if err == io.EOF {
+			return file.Stamps, nil
+		}
+		if err != nil {
+			return nil, err
+		}
+		switch value := token.(type) {
+		case xml.StartElement:
+			return nil, fmt.Errorf("multiple XML roots in signature %s", name)
+		case xml.CharData:
+			if len(bytes.TrimSpace(value)) != 0 {
+				return nil, fmt.Errorf("unexpected text after signature %s", name)
+			}
+		}
+	}
+}
+
 // signatures 复制所选页面的签章及原始验证凭据，过滤其他页面的签章位置
 // 返回: []byte 签名索引条目, error 错误信息
 func (m *editorPageImport) signatures() ([]byte, error) {
@@ -1400,16 +1565,12 @@ func (m *editorPageImport) signatures() ([]byte, error) {
 		if err != nil {
 			return nil, err
 		}
-		value, err := m.readFile(loc)
+		stamps, err := m.signatureStamps(m.reader, loc)
 		if err != nil {
 			return nil, err
 		}
-		var signature SignatureFile
-		if err := xml.Unmarshal(value, &signature); err != nil {
-			return nil, err
-		}
 		matched := false
-		for _, stamp := range signature.SignedInfo.StampAnnot {
+		for _, stamp := range stamps {
 			matched = matched || m.pages[editorImportKey(stamp.PageRef)]
 		}
 		if !matched {
@@ -1461,7 +1622,7 @@ func (m *editorPageImport) merge(base *editorSource, refs []Page, annotations, s
 	}
 	var content []byte
 	if len(m.resourceXML) != 0 {
-		name, added, err := mergePackageResources(base.reader, files, base.document, m.directory, m.resourceXML)
+		name, added, err := mergePackageResources(m.ctx, base.reader, files, base.document, m.directory, m.resourceXML)
 		if err != nil {
 			return nil, err
 		}

ofdgo_editor_open.go

@@ -43,6 +43,7 @@ type editorSource struct {
 	annotationStates   map[string]map[string]editorCompositeState
 	annotationPages    map[string]bool
 	retiredAttachments map[string]bool
+	removedAttachments map[string]bool
 }
 
 // editorObjectOrigin 保留原对象的XML语义，供复制和局部更新复用
@@ -540,7 +541,10 @@ func (e *Editor) objectCapabilities(object GraphicObject, orderable map[*editorX
 		all.Stretch = object.Type == "ImageObject"
 		all.ReplaceImage = object.Type == "ImageObject"
 		all.CropImage = all.ReplaceImage
-		all.FitImage = all.ReplaceImage && axisAlignedMatrix(NewMatrix(object.ImageObject.CTM))
+		if all.ReplaceImage {
+			_, err := imageFitBasis(object.ImageObject.CTM)
+			all.FitImage = err == nil
+		}
 		return all
 	}
 	node := origin.node
@@ -578,7 +582,10 @@ func (e *Editor) objectCapabilities(object GraphicObject, orderable map[*editorX
 	all.Paint = all.Paint && e.editorPaintable(object)
 	all.ReplaceImage = all.Update && object.Type == "ImageObject"
 	all.CropImage = all.ReplaceImage
-	all.FitImage = all.ReplaceImage && axisAlignedMatrix(NewMatrix(object.ImageObject.CTM))
+	if all.ReplaceImage {
+		_, err := imageFitBasis(object.ImageObject.CTM)
+		all.FitImage = err == nil
+	}
 	if object.Type == "TextObject" {
 		all.TextContent = all.Update && object.TextObject.ReadDirection == 0 && object.TextObject.CharDirection == 0 && (all.LayoutKnown || len(object.TextObject.CGTransform) == 0)
 		all.Reflow = all.Reflow && (all.LayoutKnown || len(object.TextObject.CGTransform) == 0)
@@ -949,6 +956,17 @@ func validateEditorGeometry(object GraphicObject) error {
 			return err
 		}
 	}
+	if clips := *editorObjectClips(&object); clips != nil {
+		for _, clip := range clips.Clip {
+			for _, area := range clip.Area {
+				if area.CTM != "" {
+					if _, err := creationNumbers(area.CTM, 6); err != nil {
+						return fmt.Errorf("invalid clip transform: %w", err)
+					}
+				}
+			}
+		}
+	}
 	var alpha *int
 	switch object.Type {
 	case "TextObject":

ofdgo_editor_outline.go

@@ -16,6 +16,7 @@ package ofdgo
 
 import (
 	"bytes"
+	"context"
 	"encoding/xml"
 	"fmt"
 	"slices"
@@ -146,7 +147,11 @@ func (e *Editor) UpdateOutline(path []int, title string, page int) error {
 				}
 				content = append(content, standalone...)
 			}
-			patches = append(patches, editorXMLContent(data, actions, content))
+			if page < 0 && len(removals) == len(actions.children) {
+				patches = append(patches, editorXMLPatch{actions.start, actions.end, nil})
+			} else {
+				patches = append(patches, editorXMLContent(data, actions, content))
+			}
 		} else if page >= 0 {
 			content, err := editorXMLGenerated(e.outlineAction(page), node.name.Space)
 			if err != nil {
@@ -167,11 +172,11 @@ func (e *Editor) UpdateOutline(path []int, title string, page int) error {
 	if err != nil {
 		return err
 	}
-	value, err := editorXMLAttribute(updated, node, "Title", title)
+	patch, err := editorXMLAttributePatch(updated, node, "Title", title)
 	if err != nil {
 		return err
 	}
-	return e.setOutlineXML(editorPatchXML(updated, []editorXMLPatch{{node.start, node.end, value}}))
+	return e.setOutlineXML(editorPatchXML(updated, []editorXMLPatch{patch}))
 }
 
 // SetOutlineActions 替换目录节点的动作序列，空列表清除动作，不改变子目录
@@ -391,50 +396,34 @@ func (e *Editor) setOutlineXML(data []byte) error {
 		return err
 	}
 	var patches []editorXMLPatch
-	var leaves func(*editorXML) int
-	leaves = func(node *editorXML) int {
-		children := editorOutlineChildren(node)
-		if len(children) == 0 {
-			return 1
-		}
+	var walk func(*editorXML) (int, error)
+	walk = func(node *editorXML) (int, error) {
 		count := 0
-		for _, child := range children {
-			count += leaves(child)
-		}
-		return count
-	}
-	var walk func(*editorXML) error
-	walk = func(node *editorXML) error {
-		if node.attr("Count") != "" {
-			count := 0
-			for _, child := range editorOutlineChildren(node) {
-				count += leaves(child)
+		for _, child := range node.children {
+			if !child.matchesOFD("OutlineElem") {
+				continue
 			}
-			value, err := editorXMLAttribute(data, node, "Count", strconv.Itoa(count))
+			leaves, err := walk(child)
 			if err != nil {
-				return err
+				return 0, err
 			}
-			updated, err := parseEditorXML(value)
+			count += leaves
+		}
+		if value := strconv.Itoa(count); node.attr("Count") != "" && node.attr("Count") != value {
+			patch, err := editorXMLAttributePatch(data, node, "Count", value)
 			if err != nil {
-				return err
-			}
-			if node.open != node.end {
-				patches = append(patches, editorXMLPatch{node.start, node.open, value[:updated.open]})
-			} else {
-				patches = append(patches, editorXMLPatch{node.start, node.end, value})
+				return 0, err
 			}
+			patches = append(patches, patch)
 		}
-		for _, child := range editorOutlineChildren(node) {
-			if err := walk(child); err != nil {
-				return err
-			}
-		}
-		return nil
+		return max(1, count), nil
 	}
-	if err := walk(root); err != nil {
+	if _, err := walk(root); err != nil {
 		return err
 	}
-	data = editorPatchXML(data, patches)
+	if len(patches) > 0 {
+		data = editorPatchXML(data, patches)
+	}
 	current, err := e.outlineXML()
 	if err != nil {
 		return err
@@ -453,52 +442,93 @@ func (e *Editor) setOutlineXML(data []byte) error {
 
 // withOutlines 将修改后的目录写入文档，清除指向已删除页面的新增跳转
 // 入参: data 文档原文
-// 返回: []byte 更新文档, error 错误信息
+// 返回: []byte 更新文档, error 解析或取消错误
 func (e *Editor) withOutlines(data []byte) ([]byte, error) {
 	if e.outlines == nil {
 		return data, nil
 	}
-	outline, err := parseEditorXML(e.outlines)
+	ctx := context.Background()
+	if e.output != nil {
+		ctx = e.output.ctx
+	}
+	outline, err := parseEditorXMLContext(ctx, e.outlines)
 	if err != nil {
 		return nil, err
 	}
-	valid := make(map[string]int, len(e.pages))
-	for i, page := range e.pages {
-		valid[page.ID] = i
+	valid := make(map[string]bool, len(e.pages))
+	for _, page := range e.pages {
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
+		if id := editorResourceID(page.ID); id != "" {
+			valid[id] = true
+		}
 	}
 	var removals []editorXMLPatch
-	var walk func(*editorXML)
-	walk = func(node *editorXML) {
+	var walk func(*editorXML) error
+	walk = func(node *editorXML) error {
+		if err := ctx.Err(); err != nil {
+			return err
+		}
 		if actions := node.child("Actions"); actions != nil {
+			start := len(removals)
 			for _, action := range actions.children {
+				if err := ctx.Err(); err != nil {
+					return err
+				}
 				if !action.matchesOFD("Action") {
 					continue
 				}
 				if target := action.child("Goto"); target != nil {
 					if dest := target.child("Dest"); dest != nil {
-						if _, ok := resourceValue(valid, dest.attr("PageID")); !ok {
+						if !valid[editorResourceID(dest.attr("PageID"))] {
 							removals = append(removals, editorXMLPatch{action.start, action.end, nil})
 						}
 					}
 				}
 			}
+			if len(removals) > start && len(removals)-start == len(actions.children) {
+				removals = append(removals[:start], editorXMLPatch{actions.start, actions.end, nil})
+			}
 		}
 		for _, child := range editorOutlineChildren(node) {
-			walk(child)
+			if err := walk(child); err != nil {
+				return err
+			}
 		}
+		return nil
 	}
-	walk(outline)
-	value := editorPatchXML(e.outlines, removals)
-	root, err := parseEditorXML(data)
+	if err := walk(outline); err != nil {
+		return nil, err
+	}
+	value := e.outlines
+	if len(outline.children) == 0 {
+		value = nil
+	} else if len(removals) > 0 {
+		value = editorPatchXML(value, removals)
+	}
+	root, err := parseEditorXMLContext(ctx, data)
 	if err != nil {
 		return nil, err
 	}
+	var patch editorXMLPatch
 	if node := root.child("Outlines"); node != nil {
-		return editorPatchXML(data, []editorXMLPatch{{node.start, node.end, value}}), nil
+		patch = editorXMLPatch{node.start, node.end, value}
+	} else if len(value) > 0 {
+		pages := root.child("Pages")
+		if pages == nil {
+			return nil, fmt.Errorf("document has no Pages")
+		}
+		patch = editorXMLPatch{pages.end, pages.end, value}
+	} else {
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
+		return data, nil
 	}
-	pages := root.child("Pages")
-	if pages == nil {
-		return nil, fmt.Errorf("document has no Pages")
+	data = editorPatchXML(data, []editorXMLPatch{patch})
+	if err := ctx.Err(); err != nil {
+		return nil, err
 	}
-	return editorPatchXML(data, []editorXMLPatch{{pages.end, pages.end, value}}), nil
+	return data, nil
 }

ofdgo_editor_package.go

@@ -28,7 +28,7 @@ import (
 	"strings"
 )
 
-// sourceParts 生成编辑快照的XML和新增资源，删页时同步清理标准引用
+// sourceParts 生成编辑快照的XML和新增资源，同步清理已删除页面及附件的引用
 // 入参: ctx 取消上下文, progress 保存进度回调，预览时为nil
 // 返回: map[string][]byte 替换及新增条目, error 错误信息
 func (e *Editor) sourceParts(ctx context.Context, progress editorProgress) (map[string][]byte, error) {
@@ -135,7 +135,11 @@ func (e *Editor) sourcePartsPrepared(progress editorProgress, generated map[stri
 		if err != nil {
 			return nil, err
 		}
-		resourcePath, added, err := mergePackageResources(reader, parts, source.document, source.directory, data)
+		ctx := context.Background()
+		if e.output != nil {
+			ctx = e.output.ctx
+		}
+		resourcePath, added, err := mergePackageResources(ctx, reader, parts, source.document, source.directory, data)
 		if err != nil {
 			return nil, err
 		}
@@ -263,8 +267,8 @@ func (e *Editor) sourcePartsPrepared(progress editorProgress, generated map[stri
 		}
 		parts[name] = updated
 	}
-	if originalCount != len(source.pages) || len(source.annotationPages) != 0 || len(e.removedPages) != 0 {
-		if err := e.prunePageReferences(parts, generated); err != nil {
+	if originalCount != len(source.pages) || len(source.annotationPages) != 0 || len(e.removedPages) != 0 || len(source.removedAttachments) != 0 {
+		if err := e.pruneDocumentReferences(parts, generated); err != nil {
 			return nil, err
 		}
 	}

ofdgo_editor_pages.go

@@ -15,18 +15,21 @@
 package ofdgo
 
 import (
+	"bytes"
+	"context"
+	"encoding/xml"
 	"fmt"
 	"io"
 	"maps"
 	"strings"
 )
 
-// prunePageReferences 在输出快照中删除已移除页面的标准引用，不修改历史快照或其他文档
+// pruneDocumentReferences 在输出快照中清理已删除页面和附件的引用，不修改历史快照或其他文档
 // 沿当前文档、页面、模板、资源、注释和签名索引检查，不进入附件、私有扩展和签名原始凭据
 // 版本包保留原签名及其页面引用，避免改写其他版本共用的签名数据
 // 入参: parts 输出覆盖条目, generated 本次自产页面及引用，可为nil
-// 返回: error 读取或解析错误
-func (e *Editor) prunePageReferences(parts map[string][]byte, generated map[string]editorGeneratedReferences) error {
+// 返回: error 读取、解析或取消错误
+func (e *Editor) pruneDocumentReferences(parts map[string][]byte, generated map[string]editorGeneratedReferences) error {
 	removed := maps.Clone(e.removedPages)
 	if removed == nil {
 		removed = make(map[string]bool)
@@ -41,9 +44,13 @@ func (e *Editor) prunePageReferences(parts map[string][]byte, generated map[stri
 		delete(removed, editorResourceID(page.ID))
 	}
 	delete(removed, "")
-	if len(removed) == 0 {
+	if len(removed) == 0 && len(e.source.removedAttachments) == 0 {
 		return nil
 	}
+	ctx := context.Background()
+	if e.output != nil {
+		ctx = e.output.ctx
+	}
 	reader := e.source.reader
 	bookmarks := make(map[string]bool)
 	for _, bookmark := range e.source.document.Bookmarks.Bookmark {
@@ -52,15 +59,13 @@ func (e *Editor) prunePageReferences(parts map[string][]byte, generated map[stri
 		}
 	}
 	queue := []string{reader.documentRoot}
-	if name := e.source.document.Signatures; name != "" && !reader.OFD.DocBody[reader.documentIndex].versioned {
+	if name := e.source.document.Signatures; len(removed) != 0 && name != "" && !reader.OFD.DocBody[reader.documentIndex].versioned {
 		queue = append(queue, reader.ResPath(name))
 	}
 	seen := make(map[string]bool)
 	for len(queue) > 0 {
-		if e.output != nil {
-			if err := e.output.ctx.Err(); err != nil {
-				return err
-			}
+		if err := ctx.Err(); err != nil {
+			return err
 		}
 		name := queue[0]
 		queue = queue[1:]
@@ -71,15 +76,12 @@ func (e *Editor) prunePageReferences(parts map[string][]byte, generated map[stri
 		data, ok := parts[name]
 		if !ok {
 			var err error
-			data, err = reader.readFile(name)
+			data, err = reader.readFileViewContext(ctx, name)
 			if err != nil {
 				return err
 			}
 		} else if known := generated[name]; data == nil && known.staged != nil {
-			input := known.staged.open()
-			if e.output != nil {
-				input = imageInput{ReadCloser: input, context: e.output.ctx}
-			}
+			input := imageInput{ReadCloser: known.staged.open(), context: ctx}
 			var err error
 			data, err = io.ReadAll(input)
 			input.Close()
@@ -87,17 +89,15 @@ func (e *Editor) prunePageReferences(parts map[string][]byte, generated map[stri
 				return err
 			}
 		}
-		root, err := parseEditorXML(data)
+		root, err := parseEditorXMLContext(ctx, data)
 		if err != nil {
 			return err
 		}
 		var patches []editorXMLPatch
 		var walk func(*editorXML) error
 		walk = func(node *editorXML) error {
-			if e.output != nil {
-				if err := e.output.ctx.Err(); err != nil {
-					return err
-				}
+			if err := ctx.Err(); err != nil {
+				return err
 			}
 			if classifyOFDNamespace(node.name.Space) == ofdXMLUnknown {
 				return nil
@@ -111,6 +111,8 @@ func (e *Editor) prunePageReferences(parts map[string][]byte, generated map[stri
 					} else if bookmark := target.child("Bookmark"); bookmark != nil {
 						remove = bookmarks[bookmark.attr("Name")]
 					}
+				} else if attachment := node.child("GotoA"); attachment != nil {
+					remove = e.source.removedAttachments[attachment.attr("AttachID")]
 				}
 			case "Bookmark":
 				if node.parent != nil && node.parent.name.Local == "Bookmarks" {
@@ -180,37 +182,79 @@ func (e *Editor) prunePageReferences(parts map[string][]byte, generated map[stri
 			delete(generated, name)
 		}
 	}
-	return nil
+	return ctx.Err()
+}
+
+// pageReferenceNode 记录跳转引用扫描中的父节点及删除范围
+type pageReferenceNode struct {
+	name              string
+	start, patch      int
+	children, removed int
+	standard, drop    bool
 }
 
 // pruneCreatedPageReferences 清理创作文档中被明确删除页面的直接跳转，不检查其他目标是否可达
-// 入参: data 创作XML, removed 已删除页面标识
-// 返回: []byte 更新后的XML, error 解析错误
-func pruneCreatedPageReferences(data []byte, removed map[string]bool) ([]byte, error) {
-	root, err := parseEditorXML(data)
-	if err != nil {
-		return nil, err
-	}
+// 入参: ctx 取消上下文, data 创作XML, removed 已删除页面标识
+// 返回: []byte 更新后的XML, error 解析或取消错误
+func pruneCreatedPageReferences(ctx context.Context, data []byte, removed map[string]bool) ([]byte, error) {
+	d := xml.NewDecoder(imageInput{ReadCloser: io.NopCloser(bytes.NewReader(data)), context: ctx})
+	var stack []pageReferenceNode
 	var patches []editorXMLPatch
-	var walk func(*editorXML)
-	walk = func(node *editorXML) {
-		if node.name.Space != ofdNamespace2016 {
-			return
+	root := false
+	for {
+		if err := ctx.Err(); err != nil {
+			return nil, err
 		}
-		if node.name.Local == "Action" {
-			if target := node.child("Goto"); target != nil {
-				if dest := target.child("Dest"); dest != nil && removed[editorResourceID(dest.attr("PageID"))] {
-					patches = append(patches, editorXMLPatch{start: node.start, end: node.end})
-					return
+		start := int(d.InputOffset())
+		token, err := d.Token()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, err
+		}
+		switch token := token.(type) {
+		case xml.StartElement:
+			node := pageReferenceNode{name: token.Name.Local, start: start, patch: len(patches), standard: token.Name.Space == ofdNamespace2016}
+			if len(stack) == 0 {
+				if root {
+					return nil, fmt.Errorf("multiple XML roots")
+				}
+				root = true
+			} else {
+				parent := &stack[len(stack)-1]
+				parent.children++
+				node.standard = node.standard && parent.standard
+			}
+			if node.standard && node.name == "Dest" && len(stack) >= 2 && stack[len(stack)-1].name == "Goto" && stack[len(stack)-2].name == "Action" {
+				for _, attr := range token.Attr {
+					if attr.Name.Space == "" && attr.Name.Local == "PageID" && removed[editorResourceID(attr.Value)] {
+						stack[len(stack)-2].drop = true
+					}
+				}
+			}
+			stack = append(stack, node)
+		case xml.EndElement:
+			node := stack[len(stack)-1]
+			stack = stack[:len(stack)-1]
+			if node.drop || node.standard && node.name == "Actions" && node.removed > 0 && node.children == node.removed {
+				patches = append(patches[:node.patch], editorXMLPatch{start: node.start, end: int(d.InputOffset())})
+				if len(stack) > 0 {
+					stack[len(stack)-1].removed++
 				}
 			}
 		}
-		for _, child := range node.children {
-			walk(child)
-		}
 	}
-	walk(root)
-	return editorPatchXML(data, patches), nil
+	if !root {
+		return nil, fmt.Errorf("empty XML document")
+	}
+	if len(patches) > 0 {
+		data = editorPatchXML(data, patches)
+	}
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+	return data, nil
 }
 
 // editorPageLocation 按所在XML解析引用，绝对路径以包根目录为基准

ofdgo_editor_resource_scope.go

@@ -20,7 +20,13 @@ import (
 	"slices"
 )
 
-// resourceReferenceScopes 复用结构依赖归集文档引用，同文档索引共用只读结果，跨文档索引独立合并
+// editorResourceScope 记录资源索引的文档归属链，引用集合只读
+type editorResourceScope struct {
+	parent int
+	refs   *editorResourceRefs
+}
+
+// resourceReferenceScopes 按文档归集引用，归属相同的资源索引复用只读结果
 // 入参: ctx 取消上下文, documents 文档入口, resources 资源索引, references 文件引用, selected 限定的文档入口，空值统计全部文档
 // 返回: map[string]*editorResourceRefs 各资源索引的引用，依赖不完整或引用无法归属时为空, error 取消错误
 func resourceReferenceScopes(ctx context.Context, documents map[string]bool, resources []string, references map[string]*editorResourceRefs, selected string) (map[string]*editorResourceRefs, error) {
@@ -29,8 +35,9 @@ func resourceReferenceScopes(ctx context.Context, documents map[string]bool, res
 		indexes[name] = true
 	}
 	used := make(map[string]bool)
-	result := make(map[string]*editorResourceRefs)
-	shared := make(map[string]bool)
+	owners := make(map[string]int)
+	groups := []editorResourceScope{{}}
+	groupIDs := make(map[editorResourceScope]int)
 	for _, entry := range slices.Sorted(maps.Keys(documents)) {
 		scope := map[string]bool{entry: true}
 		queue := []string{entry}
@@ -89,17 +96,14 @@ func resourceReferenceScopes(ctx context.Context, documents map[string]bool, res
 			if !indexes[name] {
 				continue
 			}
-			if result[name] == nil {
-				result[name] = refs
-				continue
+			key := editorResourceScope{parent: owners[name], refs: refs}
+			id := groupIDs[key]
+			if id == 0 {
+				id = len(groups)
+				groups = append(groups, key)
+				groupIDs[key] = id
 			}
-			if !shared[name] {
-				merged := &editorResourceRefs{ids: make(map[string]bool), fonts: make(map[string]*editorFontUsage)}
-				merged.merge(result[name])
-				result[name] = merged
-				shared[name] = true
-			}
-			result[name].merge(refs)
+			owners[name] = id
 		}
 	}
 	for name, refs := range references {
@@ -107,5 +111,27 @@ func resourceReferenceScopes(ctx context.Context, documents map[string]bool, res
 			return nil, nil
 		}
 	}
+	result := make(map[string]*editorResourceRefs, len(owners))
+	merged := make(map[int]*editorResourceRefs)
+	for name, id := range owners {
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
+		refs := merged[id]
+		if refs == nil {
+			refs = groups[id].refs
+			if groups[id].parent != 0 {
+				refs = &editorResourceRefs{ids: make(map[string]bool), fonts: make(map[string]*editorFontUsage)}
+				for next := id; next != 0; next = groups[next].parent {
+					if err := ctx.Err(); err != nil {
+						return nil, err
+					}
+					refs.merge(groups[next].refs)
+				}
+			}
+			merged[id] = refs
+		}
+		result[name] = refs
+	}
 	return result, ctx.Err()
 }

ofdgo_editor_resources.go

@@ -72,6 +72,7 @@ func (e *Editor) compactResourceReferences(parts map[string][]byte, reader *Read
 	if e.output != nil {
 		ctx = e.output.ctx
 	}
+	progress = progress.withContext(ctx)
 	scope, err := reader.versionResourceFiles(ctx, parts, generated)
 	if err != nil {
 		return nil, err
@@ -172,14 +173,14 @@ func (e *Editor) compactResourceReferences(parts map[string][]byte, reader *Read
 		data, ok := parts[name]
 		if !ok {
 			var err error
-			data, err = reader.readFile(name)
+			data, err = reader.readFileViewContext(ctx, name)
 			if err != nil {
 				return nil, err
 			}
 		}
-		root, err := parseEditorXML(data)
+		root, err := parseEditorXMLContext(ctx, data)
 		if err != nil {
-			return nil, nil
+			return nil, ctx.Err()
 		}
 		usageRefs := refs
 		if multiple || prune {
@@ -190,6 +191,9 @@ func (e *Editor) compactResourceReferences(parts map[string][]byte, reader *Read
 		for _, group := range root.children {
 			var members []editorXMLPatch
 			for _, node := range group.children {
+				if err := ctx.Err(); err != nil {
+					return nil, err
+				}
 				field := ""
 				if group.name.Local == "Fonts" && node.name.Local == "Font" {
 					field = "FontFile"
@@ -264,6 +268,7 @@ func (e *Editor) compactResourceReferences(parts map[string][]byte, reader *Read
 	for name := range usedFiles {
 		delete(removed, name)
 	}
+	var fontCache editorSourceFontCache
 	for i, name := range ordered {
 		if err := progress.report("fonts", i, len(ordered)); err != nil {
 			return nil, err
@@ -277,10 +282,16 @@ func (e *Editor) compactResourceReferences(parts map[string][]byte, reader *Read
 		if err != nil {
 			return nil, err
 		}
-		subset, err := e.backends.FontResources.SubsetSourceFont(data, FontUsage{Characters: slices.Sorted(maps.Keys(usage.chars)), Glyphs: slices.Sorted(maps.Keys(usage.glyphs)), Unsafe: usage.unsafe})
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
+		subset, err := fontCache.subset(ctx, e.backends.FontResources, data, usage)
 		if err != nil {
 			return nil, fmt.Errorf("subset font %s: %w", name, err)
 		}
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
 		if subset != nil {
 			updates[name] = subset
 		}

ofdgo_editor_selection.go

@@ -42,7 +42,7 @@ func (e *Editor) SelectionBounds(page int, objects, annotations []string) (Box,
 // 入参: page 页面索引, objects 正文标识, annotations 注解标识, matrix 有限可逆变换
 // 返回: error 标识、变换或编辑错误
 func (e *Editor) TransformSelection(page int, objects, annotations []string, matrix Matrix) error {
-	if _, ok := matrix.Invert(); !ok || !finite(matrix.a) || !finite(matrix.b) || !finite(matrix.c) || !finite(matrix.d) || !finite(matrix.e) || !finite(matrix.f) {
+	if _, ok := matrix.Invert(); !ok {
 		return fmt.Errorf("selection transform must be finite and invertible")
 	}
 	if matrix == IdentityMatrix {

ofdgo_editor_transform.go

@@ -26,7 +26,7 @@ import (
 // 入参: page 页面索引, ids 对象标识, matrix 页面变换
 // 返回: error 错误信息
 func (e *Editor) TransformObjectsMatrix(page int, ids []string, matrix Matrix) error {
-	if _, ok := matrix.Invert(); !ok || !finite(matrix.a) || !finite(matrix.b) || !finite(matrix.c) || !finite(matrix.d) || !finite(matrix.e) || !finite(matrix.f) {
+	if _, ok := matrix.Invert(); !ok {
 		return fmt.Errorf("object transform must be finite and invertible")
 	}
 	objects, _, err := e.selectedObjects(page, ids)
@@ -149,7 +149,7 @@ func (e *Editor) CropImage(page int, id string, box Box) error {
 	return e.UpdateObject(page, id, object)
 }
 
-// FitImage 按原始像素比例居中适应或填充当前Boundary，保留直角旋转及镜像方向
+// FitImage 按原始像素比例居中适应或填充当前Boundary，保留旋转、镜像及斜切方向
 // 保留原始图片，不重采样；重设裁剪，一次撤销恢复原布局
 // 入参: page 页面索引, id 图片对象标识, mode 为contain（完整显示）或cover（填满裁剪）
 // 返回: error 错误信息
@@ -185,7 +185,11 @@ func (obj TextObject) TextFrame() (Box, error) {
 	if !ok {
 		return Box{}, fmt.Errorf("text transform is not invertible")
 	}
-	return m.TransformBox(Box{W: box.W, H: box.H}), nil
+	frame := m.TransformBox(Box{W: box.W, H: box.H})
+	if !finite(frame.X) || !finite(frame.Y) || !finite(frame.W) || !finite(frame.H) || frame.W <= 0 || frame.H <= 0 {
+		return Box{}, fmt.Errorf("text frame exceeds finite range")
+	}
+	return frame, nil
 }
 
 // ResizeTextFrame 调整文字本地坐标的左侧偏移及宽度，保留页面方向；重新排版后通过UpdateObject提交
@@ -208,7 +212,13 @@ func (obj TextObject) ResizeTextFrame(offset, width float64) (TextObject, error)
 	frame.X += offset
 	frame.W = width
 	box := m.TransformBox(frame)
+	if !finite(box.X) || !finite(box.Y) || !finite(box.W) || !finite(box.H) || box.W <= 0 || box.H <= 0 {
+		return TextObject{}, fmt.Errorf("resized text frame exceeds finite range")
+	}
 	obj.CTM = TranslationMatrix(-box.X, -box.Y).Multiply(m).Multiply(TranslationMatrix(offset, 0)).String()
+	if _, err := creationNumbers(obj.CTM, 6); err != nil {
+		return TextObject{}, err
+	}
 	obj.Boundary = editorBoxString(box)
 	return obj, nil
 }
@@ -536,7 +546,29 @@ func cropImageObject(image *ImageObject, box Box) error {
 	return nil
 }
 
-// fitImage 将原始像素比例应用到当前图片框，适应时保留空白，填充时裁掉超出部分
+// imageFitBasis 提取图片变换的单位轴方向，保留旋转、镜像和斜切夹角
+// 入参: ctm 原始变换，空值使用默认方向
+// 返回: Matrix 单位轴矩阵, error 无效或退化变换
+func imageFitBasis(ctm string) (Matrix, error) {
+	if ctm != "" {
+		if _, err := creationNumbers(ctm, 6); err != nil {
+			return Matrix{}, err
+		}
+	}
+	m := NewMatrix(ctm)
+	x, y := math.Hypot(m.a, m.b), math.Hypot(m.c, m.d)
+	if x == 0 || y == 0 || !finite(x) || !finite(y) {
+		return Matrix{}, fmt.Errorf("image fitting requires nonzero finite axes")
+	}
+	m.a, m.b, m.c, m.d = m.a/x, m.b/x, m.c/y, m.d/y
+	m.e, m.f = 0, 0
+	if _, ok := m.Invert(); !ok {
+		return Matrix{}, fmt.Errorf("image fitting requires an invertible transform")
+	}
+	return m, nil
+}
+
+// fitImage 按原像素比例和轴方向布局，适应使用变换后边界，填充使用逆变换后的框范围
 // 入参: obj 图片对象副本, mode 为contain或cover
 // 返回: error 错误信息
 func (e *Editor) fitImage(obj *ImageObject, mode string) error {
@@ -547,34 +579,38 @@ func (e *Editor) fitImage(obj *ImageObject, mode string) error {
 	if err != nil {
 		return err
 	}
-	m := NewMatrix(obj.CTM)
-	if obj.CTM == "" {
-		m = Matrix{a: box.W, d: box.H}
-	}
-	if !axisAlignedMatrix(m) {
-		return fmt.Errorf("image fitting requires an axis-aligned transform")
+	m, err := imageFitBasis(obj.CTM)
+	if err != nil {
+		return err
 	}
 	size, err := e.editorImage(obj.ResourceID)
 	if err != nil {
 		return err
 	}
 	w, h := float64(size.X), float64(size.Y)
-	if m.a == 0 {
-		w, h = h, w
-	}
-	scale := math.Min(box.W/w, box.H/h)
-	if mode == "cover" {
-		scale = math.Max(box.W/w, box.H/h)
-	}
-	if m.a == 0 {
-		m.b, m.c = math.Copysign(float64(size.X)*scale, m.b), math.Copysign(float64(size.Y)*scale, m.c)
-	} else {
-		m.a, m.d = math.Copysign(w*scale, m.a), math.Copysign(h*scale, m.d)
-	}
-	m.e, m.f = 0, 0
+	m.a, m.b, m.c, m.d = m.a*w, m.b*w, m.c*h, m.d*h
 	full := m.TransformBox(Box{W: 1, H: 1})
+	scale := math.Min(box.W/full.W, box.H/full.H)
+	if mode == "cover" {
+		inverse, _ := m.Invert()
+		frame := inverse.TransformBox(Box{W: box.W, H: box.H})
+		scale = math.Max(frame.W, frame.H)
+	}
+	m.a, m.b, m.c, m.d = m.a*scale, m.b*scale, m.c*scale, m.d*scale
+	full = m.TransformBox(Box{W: 1, H: 1})
 	m.e, m.f = (box.W-full.W)/2-full.X, (box.H-full.H)/2-full.Y
-	obj.CTM, obj.Clips = m.String(), nil
+	values, original := m.Values(), NewMatrix(obj.CTM).Values()
+	for _, value := range values {
+		if !finite(value) {
+			return fmt.Errorf("image fit exceeds finite range")
+		}
+	}
+	if obj.CTM == "" || !slices.EqualFunc(values[:], original[:], func(a, b float64) bool {
+		return math.Abs(a-b) <= 1e-12*max(box.W, box.H, math.Abs(a), math.Abs(b))
+	}) {
+		obj.CTM = m.String()
+	}
+	obj.Clips = nil
 	if mode == "cover" {
 		return cropImageObject(obj, box)
 	}

ofdgo_editor_xml.go

@@ -697,6 +697,54 @@ func editorXMLEncodedFragment(data []byte, node *editorXML, namespace string) ([
 	return editorXMLGenerated(fragment, namespace)
 }
 
+// editorXMLAttributePatch 生成标准属性的起始标签补丁，不复制子树
+// 入参: data 原文, node 节点, name 属性名, value 新值
+// 返回: editorXMLPatch 标签补丁, error 编码错误
+func editorXMLAttributePatch(data []byte, node *editorXML, name, value string) (editorXMLPatch, error) {
+	patch := editorXMLPatch{start: node.start, end: node.open, data: data[node.start:node.open]}
+	if node.hasAttr(name) && node.attr(name) == value {
+		return patch, nil
+	}
+	d := xml.NewDecoder(bytes.NewReader(patch.data))
+	token, err := d.RawToken()
+	if err != nil {
+		return editorXMLPatch{}, err
+	}
+	start := token.(xml.StartElement)
+	found := false
+	for i := range start.Attr {
+		if attr := &start.Attr[i]; attr.Name.Space == "" && attr.Name.Local == name {
+			attr.Value, found = value, true
+		}
+	}
+	if !found {
+		start.Attr = append(start.Attr, xml.Attr{Name: xml.Name{Local: name}, Value: value})
+	}
+	if start.Name.Space != "" {
+		start.Name.Local = start.Name.Space + ":" + start.Name.Local
+		start.Name.Space = ""
+	}
+	for i := range start.Attr {
+		if attr := &start.Attr[i]; attr.Name.Space != "" {
+			attr.Name.Local = attr.Name.Space + ":" + attr.Name.Local
+			attr.Name.Space = ""
+		}
+	}
+	var output bytes.Buffer
+	encoder := xml.NewEncoder(&output)
+	if err := encoder.EncodeToken(start); err != nil {
+		return editorXMLPatch{}, err
+	}
+	if err := encoder.Flush(); err != nil {
+		return editorXMLPatch{}, err
+	}
+	patch.data = output.Bytes()
+	if node.open == node.end {
+		patch.data = append(patch.data[:len(patch.data)-1], '/', '>')
+	}
+	return patch, nil
+}
+
 // editorXMLAttribute 修改单个标准属性，保留节点其余原文
 // 入参: data 原文, node 节点, name 属性名, value 新值
 // 返回: []byte 修改后的节点, error 错误信息

ofdgo_geom.go

@@ -133,21 +133,78 @@ func (m Matrix) String() string {
 	return fmt.Sprintf("%s %s %s %s %s %s", ofdNumber(m.a), ofdNumber(m.b), ofdNumber(m.c), ofdNumber(m.d), ofdNumber(m.e), ofdNumber(m.f))
 }
 
-// Invert 求逆矩阵
-// 返回: Matrix 逆矩阵, bool 是否可逆
+// Invert 求仿射矩阵的逆变换
+// 返回: Matrix 逆矩阵，失败时返回单位矩阵, bool 是否存在有限逆矩阵
 func (m Matrix) Invert() (Matrix, bool) {
-	det := m.a*m.d - m.b*m.c
-	if math.Abs(det) < 1e-9 {
+	for _, value := range m.Values() {
+		if !finite(value) {
+			return IdentityMatrix, false
+		}
+	}
+	det, ds := matrixProductDifference(m.a, m.d, m.b, m.c)
+	x, xs := matrixProductDifference(m.c, m.f, m.d, m.e)
+	y, ys := matrixProductDifference(m.b, m.e, m.a, m.f)
+	if det != 0 && ds && xs && ys {
+		n := Matrix{a: m.d / det, b: -m.b / det, c: -m.c / det, d: m.a / det, e: x / det, f: y / det}
+		valid := true
+		for _, value := range n.Values() {
+			valid = valid && finite(value)
+		}
+		if valid {
+			return n, true
+		}
+	}
+	determinant, exponent := matrixProductSum(m.a, m.d, -m.b, m.c)
+	if determinant == 0 {
 		return IdentityMatrix, false
 	}
-	return Matrix{
-		a: m.d / det,
-		b: -m.b / det,
-		c: -m.c / det,
-		d: m.a / det,
-		e: (m.c*m.f - m.d*m.e) / det,
-		f: (m.b*m.e - m.a*m.f) / det,
-	}, true
+	divide := func(value float64, power int) float64 {
+		mantissa, shift := math.Frexp(value)
+		return math.Ldexp(mantissa/determinant, power+shift-exponent)
+	}
+	x, xe := matrixProductSum(m.c, m.f, -m.d, m.e)
+	y, ye := matrixProductSum(m.b, m.e, -m.a, m.f)
+	n := Matrix{a: divide(m.d, 0), b: divide(-m.b, 0), c: divide(-m.c, 0), d: divide(m.a, 0), e: divide(x, xe), f: divide(y, ye)}
+	for _, value := range n.Values() {
+		if !finite(value) {
+			return IdentityMatrix, false
+		}
+	}
+	return n, true
+}
+
+// matrixProductDifference 计算两个乘积之差，检查溢出、下溢及相消造成的精度损失
+// 入参: a 第一个乘数, b 第二个乘数, c 第三个乘数, d 第四个乘数
+// 返回: float64 乘积之差, bool 是否可直接用于求逆
+func matrixProductDifference(a, b, c, d float64) (float64, bool) {
+	x, y := a*b, c*d
+	value := x - y
+	if !finite(value) || x == 0 && a != 0 && b != 0 || y == 0 && c != 0 && d != 0 {
+		return value, false
+	}
+	return value, x == 0 && y == 0 || math.Abs(value) >= 0x1p-1022 && math.Abs(value) >= 0x1p-48*math.Max(math.Abs(x), math.Abs(y))
+}
+
+// matrixProductSum 以尾数及指数累加两个乘积，保留乘法舍入残差
+// 入参: a 第一个乘数, b 第二个乘数, c 第三个乘数, d 第四个乘数
+// 返回: float64 结果尾数, int 二进制指数
+func matrixProductSum(a, b, c, d float64) (float64, int) {
+	a, ae := math.Frexp(a)
+	b, be := math.Frexp(b)
+	c, ce := math.Frexp(c)
+	d, de := math.Frexp(d)
+	x, y := a*b, c*d
+	xe, ye := ae+be, ce+de
+	power := max(xe, ye)
+	if x == 0 {
+		power = ye
+	} else if y == 0 {
+		power = xe
+	}
+	value := math.Ldexp(x, xe-power) + math.Ldexp(y, ye-power)
+	value += math.Ldexp(math.FMA(a, b, -x), xe-power) + math.Ldexp(math.FMA(c, d, -y), ye-power)
+	value, shift := math.Frexp(value)
+	return value, power + shift
 }
 
 // TranslationMatrix 构造平移矩阵

ofdgo_package.go

@@ -16,6 +16,7 @@ package ofdgo
 
 import (
 	"bytes"
+	"context"
 	"path"
 	"slices"
 	"strconv"
@@ -78,9 +79,12 @@ func packageAvailableName(reader *Reader, files map[string][]byte, name string)
 }
 
 // mergePackageResources 合并新增资源定义，保留原索引、路径基准与未知字段
-// 入参: reader 原包, parts 待写入条目, doc 文档, directory 文档目录, added 新增资源XML，文件引用使用绝对包路径
-// 返回: string 资源索引路径, bool 是否需要新增文档引用, error 错误信息
-func mergePackageResources(reader *Reader, parts map[string][]byte, doc *Document, directory string, added []byte) (string, bool, error) {
+// 入参: ctx 取消上下文, reader 原包, parts 待写入条目, doc 文档, directory 文档目录, added 新增资源XML，文件引用使用绝对包路径
+// 返回: string 资源索引路径, bool 是否需要新增文档引用, error 读取、解析或取消错误
+func mergePackageResources(ctx context.Context, reader *Reader, parts map[string][]byte, doc *Document, directory string, added []byte) (string, bool, error) {
+	if err := ctx.Err(); err != nil {
+		return "", false, err
+	}
 	if len(doc.CommonData.DocumentRes) == 0 {
 		name := packageAvailableName(reader, parts, path.Join(directory, "DocumentRes.xml"))
 		parts[name] = added
@@ -93,42 +97,54 @@ func mergePackageResources(reader *Reader, parts map[string][]byte, doc *Documen
 	data, ok := parts[name]
 	if !ok {
 		var err error
-		data, err = reader.readFile(name)
+		data, err = reader.readFileViewContext(ctx, name)
 		if err != nil {
 			return "", false, err
 		}
 	}
-	addition, err := parseEditorXML(added)
+	addition, err := parseEditorXMLContext(ctx, added)
 	if err != nil {
 		return "", false, err
 	}
 	order := []string{"ColorSpaces", "DrawParams", "Fonts", "MultiMedias", "CompositeGraphicUnits"}
 	for _, group := range addition.children {
-		root, err := parseEditorXML(data)
+		root, err := parseEditorXMLContext(ctx, data)
 		if err != nil {
 			return "", false, err
 		}
 		target := root.child(group.name.Local)
-		context := root
+		scope := root
+		used := make(map[[2]string]bool)
 		if target != nil {
-			context = target
+			scope = target
+			for _, old := range target.children {
+				if err := ctx.Err(); err != nil {
+					return "", false, err
+				}
+				if old.matchesOFD(old.name.Local) {
+					used[[2]string{old.name.Local, editorImportKey(old.attr("ID"))}] = true
+				}
+			}
 		}
 		var content []byte
 		for _, node := range group.children {
-			if target != nil && slices.ContainsFunc(target.children, func(old *editorXML) bool {
-				return old.matchesOFD(node.name.Local) && old.attr("ID") == node.attr("ID")
-			}) {
+			if err := ctx.Err(); err != nil {
+				return "", false, err
+			}
+			key := [2]string{node.name.Local, editorImportKey(node.attr("ID"))}
+			if used[key] {
 				continue
 			}
 			entry, err := editorXMLStandalone(added[node.start:node.end], node)
 			if err != nil {
 				return "", false, err
 			}
-			entry, err = editorXMLGenerated(entry, context.name.Space)
+			entry, err = editorXMLGenerated(entry, scope.name.Space)
 			if err != nil {
 				return "", false, err
 			}
 			content = append(content, entry...)
+			used[key] = true
 		}
 		if len(content) == 0 {
 			continue
@@ -155,6 +171,9 @@ func mergePackageResources(reader *Reader, parts map[string][]byte, doc *Documen
 			data = editorPatchXML(data, []editorXMLPatch{{position, position, content}})
 		}
 	}
+	if err := ctx.Err(); err != nil {
+		return "", false, err
+	}
 	parts[name] = data
 	return name, false, nil
 }

ofdgo_writer.go

@@ -346,11 +346,15 @@ func (e *Editor) writeParts(write func(string, []byte, bool) error, progress edi
 // 返回: error 写入错误
 func (e *Editor) writePartsWithPages(write func(string, []byte, bool) error, progress editorProgress, includePages bool) error {
 	if len(e.removedPages) != 0 {
+		ctx := context.Background()
+		if e.output != nil {
+			ctx = e.output.ctx
+		}
 		output := write
 		write = func(name string, data []byte, binary bool) error {
 			if !binary && strings.EqualFold(path.Ext(name), ".xml") {
 				var err error
-				data, err = pruneCreatedPageReferences(data, e.removedPages)
+				data, err = pruneCreatedPageReferences(ctx, data, e.removedPages)
 				if err != nil {
 					return err
 				}