feat(图文处理): 优化图文缓存与导出处理

ofdgo.go

@@ -72,7 +72,7 @@ func NewRenderer(reader *Reader, opts ...RendererOption) *Renderer {
 		DrawParams:            reader.drawParamCache,
 		CompositeGraphicUnits: reader.compositeGraphicUnitCache,
 		templatePageCache:     make(map[string]*PageContent),
-		imageCache:            renderCache[string, image.Image]{limit: imageCacheLimit},
+		imageCache:            &renderCache[string, image.Image]{limit: imageCacheLimit},
 		backends:              defaultRenderBackends(),
 		backendStates:         make(map[any]any),
 	}

ofdgo_archive.go

@@ -64,6 +64,9 @@ func WriteArchive(ctx context.Context, writer io.Writer, files []ArchiveFile, op
 				return count, err
 			}
 		}
+		if err := ctx.Err(); err != nil {
+			return count, err
+		}
 		method := uint16(zip.Deflate)
 		switch strings.ToLower(path.Ext(file.Name)) {
 		case ".ofd", ".pdf", ".png", ".jpg", ".jpeg":
@@ -85,8 +88,13 @@ func WriteArchive(ctx context.Context, writer io.Writer, files []ArchiveFile, op
 	if err := archive.Close(); err != nil {
 		return count, err
 	}
+	if err := ctx.Err(); err != nil {
+		return count, err
+	}
 	if options.OnProgress != nil {
-		return count, options.OnProgress(len(files), len(files))
+		if err := options.OnProgress(len(files), len(files)); err != nil {
+			return count, err
+		}
 	}
 	return count, ctx.Err()
 }

ofdgo_backend.go

@@ -92,14 +92,17 @@ type SVGBackend interface {
 	RenderSVG(renderer *Renderer, page *PageContent, writer io.Writer, mode SVGMode) (SVGResources, error)
 }
 
-// RenderDocumentPage 保存已解析页面和物理区域，不得修改源页面内容
+// RenderDocumentPage 保存输出页面及物理区域，Content非空时优先使用已解析内容
+// Content为空时通过Source从当前阅读器按需读取，后端统一调用ReadContent且不得修改源页面
 type RenderDocumentPage struct {
 	Content *PageContent
+	Source  Page
 	Box     Box
 }
 
 // PDFBackend 输出完整PDF，保留文字、链接、目录和文档信息
-// pages交由后端消费，可逐页清空Content以释放引用，不得改变页面顺序
+// pages交由后端消费，通过ReadContent逐页读取，可清空Content释放引用，不得改变页面顺序
+// 通过Renderer调用时，OutputContext为当前导出的取消上下文
 // progress返回错误时应停止输出，调用方在失败后丢弃输出
 type PDFBackend interface {
 	Backend
@@ -143,6 +146,25 @@ func (b RenderBackends) Info() BackendInfo {
 	return BackendInfo{FontResources: backendName(b.FontResources), Fonts: backendName(b.Fonts), Geometry: backendName(b.Geometry), Compiler: backendName(b.Compiler), Raster: backendName(b.Raster), SVG: backendName(b.SVG), PDF: backendName(b.PDF), EPS: backendName(b.EPS)}
 }
 
+// ReadContent 返回已有页面或按文档引用读取，不在描述对象中保留新解析的内容
+// 入参: ctx 取消上下文，nil使用后台上下文, reader 页面所属阅读器
+// 返回: *PageContent 只读页面内容, error 读取或取消错误
+func (p RenderDocumentPage) ReadContent(ctx context.Context, reader *Reader) (*PageContent, error) {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+	if p.Content != nil {
+		return p.Content, nil
+	}
+	if reader == nil || p.Source.BaseLoc == "" {
+		return nil, fmt.Errorf("missing document page source")
+	}
+	return reader.PageContentContext(ctx, p.Source)
+}
+
 // WithRenderBackends 替换完整后端组合，未配置的能力不会沿用默认实现
 // 入参: backends 后端组合
 // 返回: RendererOption 渲染选项

ofdgo_compression.go

@@ -573,9 +573,12 @@ func (r *Renderer) writeCompressedImage(writer io.Writer, data []byte) error {
 	return err
 }
 
-// outputContext 获取仅用于输出的取消上下文
+// outputContext 优先使用当前页面上下文，否则使用输出上下文
 // 返回: context.Context 取消上下文
 func (r *Renderer) outputContext() context.Context {
+	if r.pageContext != nil {
+		return r.pageContext
+	}
 	if r.OutputContext != nil {
 		return r.OutputContext
 	}

ofdgo_font_backend.go

@@ -283,7 +283,7 @@ func (r *Renderer) resetFontBackendCache() {
 		r.fontSourcesCache.fallbackRead = false
 	}
 	r.fontMetrics = &renderCache[[32]byte, FontMetrics]{limit: 32 << 20}
-	r.glyphOutlines = renderCache[glyphOutlineKey, GeometryPath]{limit: 16 << 20}
+	r.glyphOutlines = &renderCache[glyphOutlineKey, GeometryPath]{limit: 16 << 20}
 	for _, state := range r.backendStates {
 		if fonts, ok := state.(interface{ resetFonts() }); ok {
 			fonts.resetFonts()

ofdgo_render.go

@@ -27,7 +27,7 @@ func (r *Renderer) RenderPage(page *PageContent) (*RasterPage, error) {
 // 入参: page 页面内容
 // 返回: Box 区域, error 错误信息
 func (r *Renderer) GetPageBox(page *PageContent) (Box, error) {
-	area, err := r.Reader.resolvePageArea(page.Area, page.Template)
+	area, err := r.Reader.resolvePageAreaContext(r.outputContext(), page.Area, page.Template)
 	if err != nil {
 		return Box{}, err
 	}

ofdgo_render_compile.go

@@ -396,7 +396,7 @@ func (c *semanticCompiler) textObject(object TextObject, state RenderState) erro
 	if object.Visible != nil && !*object.Visible || object.Fill != nil && !*object.Fill && (object.Stroke == nil || !*object.Stroke) {
 		return nil
 	}
-	positioned, err := c.renderer.PositionText(object, state)
+	positioned, err := c.renderer.positionText(object, state, c.textOnly && c.renderer.textContentOnly)
 	if err != nil {
 		return err
 	}

ofdgo_render_output.go

@@ -90,22 +90,34 @@ func (r *Renderer) RenderTo(page *PageContent, writer io.Writer, format string)
 }
 
 // RenderToZIP 逐页渲染并写入ZIP，文件编号按总页数补零，出错时调用方应丢弃输出
+// 读取和渲染使用OutputContext响应取消，TXT只解析文字提取所需的图元
 // 入参: writer 输出流, format svg、pdf、eps、png、jpg、jpeg或txt, indices 零基页面索引，省略则全部，按原页序去重
 // 返回: error 错误信息
 func (r *Renderer) RenderToZIP(writer io.Writer, format string, indices ...int) error {
+	renderer := *r
+	if renderer.pageContext == nil {
+		renderer.pageContext = r.outputContext()
+	}
+	r = &renderer
+	ctx := r.pageContext
 	extension, render, err := r.outputRenderer(format)
 	if err != nil {
 		return err
 	}
-	count, err := r.Reader.PageCount()
+	if err := r.Compression.Validate(); err != nil {
+		return err
+	}
+	doc, err := r.Reader.DocContext(ctx)
 	if err != nil {
 		return err
 	}
+	count := len(doc.Pages.Page)
 	indices, err = exportPageIndices(count, indices)
 	if err != nil {
 		return err
 	}
-	archive := zip.NewWriter(writer)
+	var countWritten int64
+	archive := zip.NewWriter(convertWriter{context: ctx, writer: writer, count: &countWritten})
 	configureArchive(archive, r.Compression)
 	method := zip.Deflate
 	if extension == "png" || extension == "jpg" {
@@ -116,7 +128,7 @@ func (r *Renderer) RenderToZIP(writer io.Writer, format string, indices ...int)
 		return err
 	}
 	for i, index := range indices {
-		page, err := r.Reader.PageContentByIndex(index)
+		page, err := r.Reader.readPageContent(ctx, doc.Pages.Page[index], extension == "txt", false)
 		if err != nil {
 			return fmt.Errorf("failed to read page %d: %w", index+1, err)
 		}
@@ -130,34 +142,59 @@ func (r *Renderer) RenderToZIP(writer io.Writer, format string, indices ...int)
 		if err := render(page, entry); err != nil {
 			return fmt.Errorf("failed to export page %d: %w", index+1, err)
 		}
+		if err := ctx.Err(); err != nil {
+			return err
+		}
 		if err := r.exportProgress(i+1, len(indices)); err != nil {
 			return err
 		}
 	}
-	return archive.Close()
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	if err := archive.Close(); err != nil {
+		return err
+	}
+	return ctx.Err()
 }
 
 // RenderToText 导出页面原文为UTF-8文本，以换行分隔非空文本对象
 // 入参: page 页面内容, writer 输出流
 // 返回: error 错误信息
 func (r *Renderer) RenderToText(page *PageContent, writer io.Writer) error {
-	text, err := r.PageText(page)
+	renderer := *r
+	renderer.textContentOnly = true
+	ctx := r.pageContext
+	if ctx == nil {
+		ctx = r.outputContext()
+	}
+	text, err := renderer.PageTextContext(ctx, page)
 	if err != nil {
 		return err
 	}
 	_, err = text.WriteTo(writer)
-	return err
+	if err != nil {
+		return err
+	}
+	return ctx.Err()
 }
 
 // RenderToMultiPageText 逐页导出UTF-8原文，以换行分隔非空页面，出错时调用方应丢弃输出
 // 入参: writer 输出流, indices 零基页面索引，省略则全部，按原页序去重
 // 返回: error 错误信息
 func (r *Renderer) RenderToMultiPageText(writer io.Writer, indices ...int) error {
-	count, err := r.Reader.PageCount()
+	renderer := *r
+	renderer.textContentOnly = true
+	r = &renderer
+	ctx := r.pageContext
+	if ctx == nil {
+		ctx = r.outputContext()
+	}
+	doc, err := r.Reader.DocContext(ctx)
 	if err != nil {
 		return err
 	}
-	indices, err = exportPageIndices(count, indices)
+	indices, err = exportPageIndices(len(doc.Pages.Page), indices)
 	if err != nil {
 		return err
 	}
@@ -166,7 +203,7 @@ func (r *Renderer) RenderToMultiPageText(writer io.Writer, indices ...int) error
 	}
 	written := false
 	for i, index := range indices {
-		text, err := r.PageTextByIndex(index)
+		text, err := r.PageTextByIndexContext(ctx, index)
 		if err != nil {
 			return fmt.Errorf("failed to extract page %d text: %w", index+1, err)
 		}
@@ -175,11 +212,14 @@ func (r *Renderer) RenderToMultiPageText(writer io.Writer, indices ...int) error
 			return err
 		}
 		written = written || n > 0
+		if err := ctx.Err(); err != nil {
+			return err
+		}
 		if err := r.exportProgress(i+1, len(indices)); err != nil {
 			return err
 		}
 	}
-	return nil
+	return ctx.Err()
 }
 
 // RenderToImage 渲染为光栅图
@@ -291,11 +331,12 @@ func (r *Renderer) RenderToEPS(page *PageContent, writer io.Writer) error {
 	return r.backends.EPS.RenderEPS(r, page, writer)
 }
 
-// RenderToMultiPagePDF 将文档页面导出为多页PDF
+// RenderToMultiPagePDF 将文档页面导出为多页PDF，仅预读页面区域和资源索引
 // 入参: writer 输出流, indices 零基页面索引，省略则全部，按原页序去重
 // 返回: error 错误信息
 func (r *Renderer) RenderToMultiPagePDF(writer io.Writer, indices ...int) error {
-	doc, err := r.Reader.Doc()
+	ctx := r.outputContext()
+	doc, err := r.Reader.DocContext(ctx)
 	if err != nil {
 		return err
 	}
@@ -308,15 +349,21 @@ func (r *Renderer) RenderToMultiPagePDF(writer io.Writer, indices ...int) error
 	}
 	pages := make([]RenderDocumentPage, len(indices))
 	for i, index := range indices {
-		page, err := r.Reader.PageContent(doc.Pages.Page[index])
+		ref := doc.Pages.Page[index]
+		page, err := r.Reader.readPageHeaderContext(ctx, ref)
 		if err != nil {
 			return fmt.Errorf("failed to read page %d: %w", index+1, err)
 		}
-		box, err := r.GetPageBox(page)
+		for _, res := range page.PageRes {
+			if err := r.Reader.loadResContext(ctx, "/"+resolveResourcePath(r.Reader.ResPath(ref.BaseLoc), "", res)); err != nil {
+				return fmt.Errorf("failed to read page %d resources: %w", index+1, err)
+			}
+		}
+		box, err := r.GetPageBox(&page)
 		if err != nil {
 			return fmt.Errorf("failed to read page %d area: %w", index+1, err)
 		}
-		pages[i] = RenderDocumentPage{Content: page, Box: box}
+		pages[i] = RenderDocumentPage{Source: ref, Box: box}
 	}
 	return r.renderPDFPages(pages, writer, r.OnExportProgress)
 }
@@ -325,6 +372,10 @@ func (r *Renderer) RenderToMultiPagePDF(writer io.Writer, indices ...int) error
 // 入参: contents 页面内容列表, writer 输出流
 // 返回: error 错误信息
 func (r *Renderer) RenderPagesToPDF(contents []*PageContent, writer io.Writer) error {
+	ctx := r.outputContext()
+	if err := ctx.Err(); err != nil {
+		return err
+	}
 	if len(contents) == 0 {
 		return fmt.Errorf("no pages found")
 	}
@@ -333,6 +384,9 @@ func (r *Renderer) RenderPagesToPDF(contents []*PageContent, writer io.Writer) e
 	}
 	pages := make([]RenderDocumentPage, len(contents))
 	for i, page := range contents {
+		if err := ctx.Err(); err != nil {
+			return err
+		}
 		box, err := r.GetPageBox(page)
 		if err != nil {
 			return fmt.Errorf("failed to read page %d area: %w", i+1, err)
@@ -405,11 +459,21 @@ func fillWhiteBackground(img image.Image) image.Image {
 // 入参: pages 页面列表, writer 输出流, progress 页面处理进度
 // 返回: error 错误信息
 func (r *Renderer) renderPDFPages(pages []RenderDocumentPage, writer io.Writer, progress func(int, int) error) error {
+	ctx := r.outputContext()
+	if err := ctx.Err(); err != nil {
+		return err
+	}
 	if err := r.Compression.Validate(); err != nil {
 		return err
 	}
 	if r.backends.PDF == nil {
 		return fmt.Errorf("pdf: %w", ErrBackendUnavailable)
 	}
-	return r.backends.PDF.RenderPDF(r, pages, writer, progress)
+	renderer := *r
+	renderer.pageContext = ctx
+	renderer.OutputContext = ctx
+	if err := renderer.backends.PDF.RenderPDF(&renderer, pages, writer, progress); err != nil {
+		return err
+	}
+	return ctx.Err()
 }

ofdgo_render_text.go

@@ -47,8 +47,17 @@ type glyphOutlineKey struct {
 // 入参: object 文字对象, state 继承状态
 // 返回: *PositionedText 定位结果, error 字体或几何错误
 func (r *Renderer) PositionText(object TextObject, state RenderState) (*PositionedText, error) {
+	return r.positionText(object, state, false)
+}
+
+// positionText 提取原文，按需计算字形与搜索范围
+// 入参: object 文字对象, state 继承状态, contentOnly 仅提取原文
+// 返回: *PositionedText 定位结果, error 字体或几何错误
+func (r *Renderer) positionText(object TextObject, state RenderState, contentOnly bool) (*PositionedText, error) {
 	result := &PositionedText{Run: TextRun{ID: object.ID, Text: object.Text()}}
-	result.Run.Boxes = make([]Box, len([]rune(result.Run.Text)))
+	if !contentOnly {
+		result.Run.Boxes = make([]Box, len([]rune(result.Run.Text)))
+	}
 	if state.Hidden || object.Visible != nil && !*object.Visible {
 		return result, nil
 	}
@@ -87,6 +96,9 @@ func (r *Renderer) PositionText(object TextObject, state RenderState) (*Position
 		return nil, err
 	}
 	if len(prepared.Data) == 0 {
+		if contentOnly {
+			return result, nil
+		}
 		box, _ := ParseBox(object.Boundary)
 		boundary, _ := renderObjectMatrix(object.Boundary, IdentityMatrix, state)
 		path, err := geometry.Transform(geometryRectangle(Box{W: box.W, H: box.H}), boundary)
@@ -132,9 +144,14 @@ func (r *Renderer) PositionText(object TextObject, state RenderState) (*Position
 	if recoverBaseline {
 		if text := object.Text(); text != result.Run.Text {
 			result.Run.Text = text
-			result.Run.Boxes = make([]Box, len([]rune(text)))
+			if !contentOnly {
+				result.Run.Boxes = make([]Box, len([]rune(text)))
+			}
 		}
 	}
+	if contentOnly {
+		return result, nil
+	}
 	transforms := r.textObjectGlyphTransforms(id, object)
 	codeOffset, textOffset := 0, 0
 	angle := float64(object.CharDirection) * math.Pi / 180
@@ -174,6 +191,11 @@ func (r *Renderer) PositionText(object TextObject, state RenderState) (*Position
 		}
 		positioner := NewTextPositioner(code)
 		for i, gid := range ids {
+			if i%64 == 0 && r.pageContext != nil {
+				if err := r.pageContext.Err(); err != nil {
+					return nil, err
+				}
+			}
 			path := paths[i]
 			width := float64(metrics.GlyphAdvance(gid)) * unit
 			origin := positioner.Next()
@@ -275,6 +297,11 @@ func (r *Renderer) preparedOutlines(prepared *PreparedFont, metrics FontMetrics,
 	missing := make([]uint16, 0)
 	unique := make(map[uint16]int)
 	for i, glyph := range glyphs {
+		if i%64 == 0 && r.pageContext != nil {
+			if err := r.pageContext.Err(); err != nil {
+				return nil, err
+			}
+		}
 		if path, ok := r.glyphOutlines.get(glyphOutlineKey{prepared, glyph, size}); ok {
 			result[i] = path
 			continue
@@ -313,6 +340,11 @@ func (r *Renderer) preparedOutlines(prepared *PreparedFont, metrics FontMetrics,
 		}
 		paths = make([]GeometryPath, len(missing))
 		for i, glyph := range missing {
+			if r.pageContext != nil {
+				if err := r.pageContext.Err(); err != nil {
+					return nil, err
+				}
+			}
 			var err error
 			paths[i], err = provider.GlyphOutline(glyph, size)
 			if err != nil {
@@ -320,6 +352,11 @@ func (r *Renderer) preparedOutlines(prepared *PreparedFont, metrics FontMetrics,
 			}
 		}
 	}
+	if r.pageContext != nil {
+		if err := r.pageContext.Err(); err != nil {
+			return nil, err
+		}
+	}
 	for i, path := range paths {
 		r.glyphOutlines.put(glyphOutlineKey{prepared, missing[i], size}, path, len(path)*96+128)
 	}

ofdgo_renderer.go

@@ -26,7 +26,7 @@ import (
 // OnPageText可选，接收页面绘制时同步提取的文字，不包含图案和签名外观
 // OnExportProgress可选，同步回报文档导出的已处理页数及总页数，返回错误则停止，页数完成不代表写入成功
 // TransparentBackground关闭页面白底，供嵌套图案和印章保持透明背景
-// Compression仅控制导出编码，OutputContext可取消输出压缩，nil使用后台上下文
+// Compression仅控制导出编码，OutputContext用于导出和文字提取的取消，nil使用后台上下文
 type Renderer struct {
 	Reader                *Reader
 	DPI                   float64
@@ -38,13 +38,14 @@ type Renderer struct {
 	DrawParams            map[string]*DrawParam
 	CompositeGraphicUnits map[string]*CompositeGraphicUnit
 	templatePageCache     map[string]*PageContent
-	imageCache            renderCache[string, image.Image]
+	imageCache            *renderCache[string, image.Image]
 	fontDirs              []string
 	fontFS                []fs.FS
 	decodeImages          bool
 	pageText              *PageText
 	pageContext           context.Context
 	textOnly              bool
+	textContentOnly       bool
 	backends              RenderBackends
 	backendStates         map[any]any
 	sharedBackendStates   map[any]any
@@ -54,7 +55,7 @@ type Renderer struct {
 	fontPreparations      *renderCache[[32]byte, PreparedFont]
 	fontSourcesCache      *fontSourceCache
 	fontMetrics           *renderCache[[32]byte, FontMetrics]
-	glyphOutlines         renderCache[glyphOutlineKey, GeometryPath]
+	glyphOutlines         *renderCache[glyphOutlineKey, GeometryPath]
 	renderError           error
 	patternReferences     map[*Pattern]bool
 	patternPage           *Matrix
@@ -81,7 +82,7 @@ func (r *Renderer) deviceLineWidth(width float64) float64 {
 // ClearCache 释放派生字体、图片、模板与后端缓存，不改变文档和渲染配置
 func (r *Renderer) ClearCache() {
 	r.backendStates = make(map[any]any)
-	r.imageCache = renderCache[string, image.Image]{limit: imageCacheLimit}
+	r.imageCache = &renderCache[string, image.Image]{limit: imageCacheLimit}
 	r.templatePageCache = make(map[string]*PageContent)
 	r.resetFontCache()
 }

ofdgo_renderer_measure_canvas.go

@@ -53,6 +53,7 @@ func (CanvasBackend) MeasureObject(r *Renderer, object GraphicObject, options Me
 	renderer.renderError = nil
 	renderer.pageText = nil
 	renderer.textOnly = false
+	renderer.textContentOnly = false
 	defaults := options.Defaults
 	ctx := canvas.NewContext(bounds)
 	switch object.Type {

ofdgo_renderer_output_canvas.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"image"
 	"io"
+	"strconv"
 
 	"github.com/tdewolff/canvas"
 	"github.com/tdewolff/canvas/renderers/pdf"
@@ -111,10 +112,18 @@ func (w canvasEPSWriter) Write(data []byte) (int, error) {
 // 入参: r 渲染器, pages 页面列表, writer 输出流, progress 页面处理进度
 // 返回: error 错误信息
 func (CanvasBackend) RenderPDF(r *Renderer, pages []RenderDocumentPage, writer io.Writer, progress func(int, int) error) error {
+	ctx := r.outputContext()
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	view := *r
+	view.pageContext = ctx
+	r = &view
 	if len(pages) == 0 {
 		return fmt.Errorf("no pages found")
 	}
-	navigation, err := newPDFNavigation(r, r.Reader.doc, pages)
+	doc := r.Reader.doc
+	navigation, err := newPDFNavigation(r, doc, pages)
 	if err != nil {
 		return err
 	}
@@ -139,13 +148,22 @@ func (CanvasBackend) RenderPDF(r *Renderer, pages []RenderDocumentPage, writer i
 	}
 	p.SetInfo(info.Title, info.Subject, "", info.Author, ofdCreator)
 	for i, page := range pages {
+		content, err := page.ReadContent(ctx, r.Reader)
+		if err != nil {
+			buf.Truncate(start)
+			return fmt.Errorf("failed to read page %d: %w", i+1, err)
+		}
+		if err := navigation.addPage(r, i, content, pages); err != nil {
+			buf.Truncate(start)
+			return fmt.Errorf("failed to read page %d navigation: %w", i+1, err)
+		}
 		if i > 0 {
 			p.NewPage(page.Box.W, page.Box.H)
 			renderer.images = append(renderer.images, nil)
 			renderer.text = append(renderer.text, pdfPageText{})
 		}
 		navigation.apply(p, i)
-		if err := r.renderCanvasPageToContext(canvas.NewContext(renderer), page.Content, !r.TransparentBackground); err != nil {
+		if err := r.renderCanvasPageToContext(canvas.NewContext(renderer), content, !r.TransparentBackground); err != nil {
 			buf.Truncate(start)
 			return fmt.Errorf("failed to render page %d: %w", i+1, err)
 		}
@@ -154,12 +172,29 @@ func (CanvasBackend) RenderPDF(r *Renderer, pages []RenderDocumentPage, writer i
 			return fmt.Errorf("failed to render page %d: %w", i+1, renderer.imageError)
 		}
 		pages[i].Content = nil
+		if err := ctx.Err(); err != nil {
+			buf.Truncate(start)
+			return err
+		}
 		if progress != nil {
 			if err := progress(i+1, len(pages)); err != nil {
 				buf.Truncate(start)
 				return err
 			}
 		}
+		if err := ctx.Err(); err != nil {
+			buf.Truncate(start)
+			return err
+		}
+	}
+	if doc != nil {
+		if err := navigation.addOutlines(doc.Outlines.OutlineElem, 0, navigation.bookmarks, navigation.pageIndex, pages); err != nil {
+			buf.Truncate(start)
+			return err
+		}
+	}
+	for index, outline := range navigation.Outline {
+		p.AddOutline(strconv.Itoa(index), outline.Level, 0)
 	}
 	if err := p.Close(); err != nil {
 		buf.Truncate(start)

ofdgo_renderer_pdf_canvas.go

@@ -52,6 +52,8 @@ type pdfNavigation struct {
 	Outline     []pdfOutline
 	Open        []pdfNavigationAction
 	PageOpen    map[int][]pdfNavigationAction
+	pageIndex   map[string]int
+	bookmarks   map[string]Dest
 	attachments map[string]Attachment
 	audio       map[string]*pdfgo.FileSpecification
 	video       map[string]*pdfVideoResource
@@ -149,14 +151,20 @@ func (r *pdfRenderer) glyphPath(path *canvas.Path, matrix canvas.Matrix) *canvas
 	return converted
 }
 
-// newPDFNavigation 创建PDF导航信息
-// 入参: renderer 渲染器, doc 文档结构, pages 页面数据
-// 返回: *pdfNavigation PDF导航信息, error 区域或目标错误
+// newPDFNavigation 建立文档导航与输出页索引，不读取页面图元
+// 入参: renderer 渲染器, doc 文档结构, pages 输出页面描述
+// 返回: *pdfNavigation 导航信息, error 资源或目标错误
 func newPDFNavigation(renderer *Renderer, doc *Document, pages []RenderDocumentPage) (*pdfNavigation, error) {
+	ctx := renderer.outputContext()
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
 	navigation := &pdfNavigation{
-		Link:     make(map[int][]pdfLink),
-		PageOpen: make(map[int][]pdfNavigationAction),
-		source:   renderer.Reader,
+		Link:      make(map[int][]pdfLink),
+		PageOpen:  make(map[int][]pdfNavigationAction),
+		pageIndex: make(map[string]int, len(pages)),
+		bookmarks: make(map[string]Dest),
+		source:    renderer.Reader,
 	}
 	if doc != nil && (doc.Attachments.Path != "" || len(doc.Attachments.Attachment) != 0) {
 		attachments, err := renderer.Reader.Attachments()
@@ -188,11 +196,18 @@ func newPDFNavigation(renderer *Renderer, doc *Document, pages []RenderDocumentP
 		}
 		navigation.nativeWrite = len(attachments) != 0
 	}
-	pageIndex := make(map[string]int, len(pages))
+	pageIndex := navigation.pageIndex
 	for i, page := range pages {
-		pageIndex[page.Content.ID] = i
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
+		id := page.Source.ID
+		if page.Content != nil {
+			id = page.Content.ID
+		}
+		pageIndex[id] = i
 	}
-	bookmarks := make(map[string]Dest)
+	bookmarks := navigation.bookmarks
 	if doc != nil {
 		for _, bookmark := range doc.Bookmarks.Bookmark {
 			bookmarks[bookmark.Name] = bookmark.Dest
@@ -201,30 +216,34 @@ func newPDFNavigation(renderer *Renderer, doc *Document, pages []RenderDocumentP
 			return nil, err
 		}
 	}
-	for i, page := range pages {
-		for _, source := range renderer.pageOpenActionSources(page.Content) {
-			if err := navigation.addLifecycleActions(renderer.outputContext(), source, i, bookmarks, pageIndex, pages); err != nil {
-				return nil, err
-			}
-		}
-		sources := renderer.pageActionSources(page.Content)
-		if renderer.RenderAnnotations {
-			sources = append(sources, renderer.annotationActionSources(renderer.Reader.Annots[page.Content.ID])...)
-		}
-		for _, source := range sources {
-			if err := navigation.addActions(renderer, i, source, bookmarks, pageIndex, pages); err != nil {
-				return nil, err
-			}
-		}
-	}
-	if doc != nil {
-		if err := navigation.addOutlines(doc.Outlines.OutlineElem, 0, bookmarks, pageIndex, pages); err != nil {
-			return nil, err
-		}
-	}
 	return navigation, nil
 }
 
+// addPage 收集当前页面及模板、注释中的导航，不保留页面图元
+// 入参: renderer 渲染器, index 输出页索引, page 页面内容, pages 输出页面描述
+// 返回: error 区域、目标或取消错误
+func (n *pdfNavigation) addPage(renderer *Renderer, index int, page *PageContent, pages []RenderDocumentPage) error {
+	ctx := renderer.outputContext()
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	for _, source := range renderer.pageOpenActionSources(page) {
+		if err := n.addLifecycleActions(ctx, source, index, n.bookmarks, n.pageIndex, pages); err != nil {
+			return err
+		}
+	}
+	sources := renderer.pageActionSources(page)
+	if renderer.RenderAnnotations {
+		sources = append(sources, renderer.annotationActionSources(renderer.Reader.Annots[page.ID])...)
+	}
+	for _, source := range sources {
+		if err := n.addActions(renderer, index, source, n.bookmarks, n.pageIndex, pages); err != nil {
+			return err
+		}
+	}
+	return ctx.Err()
+}
+
 // actionTarget 转换动作及资源引用，选页未包含的目标不写入
 // 入参: action 动作, page 来源页索引，负值表示文档, source 动作来源, bookmarks 书签, pageIndex 页面索引表, pages 页面数据
 // 返回: *pdfNavigationAction 导航动作，nil表示无输出动作, error 目标参数错误
@@ -298,17 +317,12 @@ func (n *pdfNavigation) addOutlines(outlines []OutlineElem, level int, bookmarks
 	return nil
 }
 
-// apply 生成链接及大纲结构，内部目标在原生写入时关联
+// apply 生成当前页链接，内部目标在原生写入时关联
 // 入参: renderer PDF渲染器, page 页面索引
 func (n *pdfNavigation) apply(renderer *pdf.PDF, page int) {
 	for _, link := range n.Link[page] {
 		renderer.AddLink("", link.Rect)
 	}
-	if page == 0 {
-		for index, outline := range n.Outline {
-			renderer.AddOutline(strconv.Itoa(index), outline.Level, 0)
-		}
-	}
 }
 
 // prepareRewrite 关联输出页引用并准备附件、事件、链接及先序大纲的替换

ofdgo_renderer_text_canvas.go

@@ -156,7 +156,7 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 		textRun = r.pageText.addRun(obj)
 	}
 	if ff == nil {
-		if textRun != nil {
+		if textRun != nil && !r.textContentOnly {
 			box, _ := ParseBox(obj.Boundary)
 			boundaryCTM := TranslationMatrix(box.X, box.Y)
 			if parentCTM != nil {
@@ -194,6 +194,10 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 			textRun.Boxes = make([]Box, len([]rune(text)))
 		}
 	}
+	if r.textOnly && r.textContentOnly {
+		ctx.Pop()
+		return
+	}
 	glyphTransforms := r.textObjectGlyphTransforms(fontID, obj)
 	hasUnderline := strings.Contains(obj.Decoration, "Underline")
 	_, shadedFill := fillPaint.(canvas.Gradient)
@@ -239,6 +243,13 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 		positioned := textCodePositioned(tc, positioner.xs, positioner.ys)
 		drawAsPath := embeddedFont || face.FauxBold > 0 || positioned || fillClip != nil || shadedFill || fillPattern != nil || shouldStroke
 		for i, glyph := range glyphs {
+			if i%64 == 0 && r.pageContext != nil {
+				if err := r.pageContext.Err(); err != nil {
+					r.renderError = err
+					ctx.Pop()
+					return
+				}
+			}
 			str := glyph.Text
 			drawAsGlyphPath := drawAsPath || glyph.GlyphID >= 0
 			if !drawAsGlyphPath {

ofdgo_search.go

@@ -96,10 +96,33 @@ func (d *textPageTokens) Token() (xml.Token, error) {
 // 入参: page 页面内容
 // 返回: *PageText 页面文字, error 错误信息
 func (r *Renderer) PageText(page *PageContent) (*PageText, error) {
+	ctx := r.pageContext
+	if ctx == nil {
+		ctx = r.outputContext()
+	}
+	return r.PageTextContext(ctx, page)
+}
+
+// PageTextContext 提取页面原文及字形位置，取消时不返回部分结果
+// 入参: ctx 取消上下文，nil使用后台上下文, page 页面内容
+// 返回: *PageText 页面文字, error 提取或取消错误
+func (r *Renderer) PageTextContext(ctx context.Context, page *PageContent) (*PageText, error) {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
 	if r.backends.Compiler == nil {
 		return nil, fmt.Errorf("%w: page text", ErrBackendUnavailable)
 	}
-	return r.backends.Compiler.PageText(r, page)
+	renderer := *r
+	renderer.pageContext = ctx
+	text, err := renderer.backends.Compiler.PageText(&renderer, page)
+	if canceled := ctx.Err(); canceled != nil {
+		return nil, canceled
+	}
+	return text, err
 }
 
 // PageTextByIndex 按页面索引提取文字，避免解析独立路径和图片图元
@@ -110,6 +133,16 @@ func (r *Renderer) PageTextByIndex(index int) (*PageText, error) {
 	if ctx == nil {
 		ctx = r.outputContext()
 	}
+	return r.PageTextByIndexContext(ctx, index)
+}
+
+// PageTextByIndexContext 按索引读取页面并提取文字，读取和页内计算均响应取消
+// 入参: ctx 取消上下文，nil使用后台上下文, index 页面索引，从0开始
+// 返回: *PageText 页面文字, error 读取、提取或取消错误
+func (r *Renderer) PageTextByIndexContext(ctx context.Context, index int) (*PageText, error) {
+	if ctx == nil {
+		ctx = context.Background()
+	}
 	doc, err := r.Reader.DocContext(ctx)
 	if err != nil {
 		return nil, err
@@ -121,7 +154,7 @@ func (r *Renderer) PageTextByIndex(index int) (*PageText, error) {
 	if err != nil {
 		return nil, err
 	}
-	return r.PageText(page)
+	return r.PageTextContext(ctx, page)
 }
 
 // String 按文本对象顺序合并原文，以换行分隔非空对象
@@ -162,7 +195,7 @@ func (p *PageText) SearchEach(ctx context.Context, query string, visit func(Text
 }
 
 // SearchText 逐页搜索原文并立即返回匹配，不保留整本文字或识别图像
-// 入参: ctx 取消上下文，页面提取之间及匹配时检查, query 搜索文字, visit 零基页码和匹配访问函数, indices 页码，省略则全部，按原页序去重
+// 入参: ctx 取消上下文，页面读取、文字提取及匹配时检查, query 搜索文字, visit 零基页码和匹配访问函数, indices 页码，省略则全部，按原页序去重
 // 返回: error 页面提取、取消或访问错误
 func (r *Renderer) SearchText(ctx context.Context, query string, visit func(int, TextMatch) error, indices ...int) error {
 	if err := ctx.Err(); err != nil {
@@ -171,11 +204,11 @@ func (r *Renderer) SearchText(ctx context.Context, query string, visit func(int,
 	if query == "" {
 		return nil
 	}
-	count, err := r.Reader.PageCount()
+	doc, err := r.Reader.DocContext(ctx)
 	if err != nil {
 		return err
 	}
-	indices, err = exportPageIndices(count, indices)
+	indices, err = exportPageIndices(len(doc.Pages.Page), indices)
 	if err != nil {
 		return err
 	}
@@ -184,7 +217,7 @@ func (r *Renderer) SearchText(ctx context.Context, query string, visit func(int,
 		if err := ctx.Err(); err != nil {
 			return err
 		}
-		text, err := r.PageTextByIndex(index)
+		text, err := r.PageTextByIndexContext(ctx, index)
 		if err != nil {
 			return fmt.Errorf("failed to search page %d: %w", index+1, err)
 		}