feat(导出文本): 新增TXT流式导出，统一导出文案

assets/webui/ofdgo.js

@@ -695,7 +695,7 @@ async function loadWASM() {
 						setProgress("正在保存", null);
 					} else if (!el.cancelExportButton.disabled) {
 						if (data.completed === data.total) {
-							setProgress("正在封装", null);
+							setProgress("正在收尾", null);
 						} else {
 							setProgress(`正在导出 ${data.completed} / ${data.total} 页`, data.completed / data.total * 100);
 						}
@@ -1540,7 +1540,7 @@ async function downloadAttachment(attachment) {
 			return;
 		}
 		downloadBytes(result.bytes, "application/octet-stream", attachment.fileName);
-		setStatus(`附件下载完成 ${formatBytes(result.bytes.length, "0 KB")}`);
+		setStatus(`附件下载完成 ${formatBytes(result.bytes.length)}`);
 	} catch (err) {
 		if (openSeq === state.openSeq) {
 			showError(err, false);
@@ -1600,9 +1600,10 @@ async function exportFile(whole, indices = null) {
 	if (!format) {
 		return;
 	}
-	const label = whole ? (format.value === "pdf" ? "PDF" : "ZIP") : format.label;
+	const archive = whole && format.value !== "pdf" && format.value !== "txt";
-	const extension = whole ? label.toLowerCase() : format.extension;
+	const label = archive ? "ZIP" : format.label;
-	const mime = whole && format.value !== "pdf" ? "application/zip" : format.mime;
+	const extension = archive ? "zip" : format.extension;
+	const mime = archive ? "application/zip" : format.mime;
 	const openSeq = state.openSeq;
 	const fileName = whole ? `${baseFileName()}.${extension}` : pageFileName(extension);
 	const pageIndex = state.pageIndex;
@@ -1627,7 +1628,7 @@ async function exportFile(whole, indices = null) {
 		if (result.blob) {
 			downloadBytes(result.blob, result.mime, fileName);
 		}
-		setStatus(`${result.label} 导出完成 ${formatBytes(result.size, result.label)}`);
+		setStatus(`${result.label} 导出完成 ${formatBytes(result.size)}`);
 	} catch (err) {
 		if (openSeq === state.openSeq) {
 			if (err.name === "AbortError") {
@@ -2737,7 +2738,7 @@ function renderAttachments() {
 		name.className = "attachment-name";
 		name.textContent = attachment.name;
 		item.append(name);
-		const detail = [attachment.format, attachment.size == null ? "" : formatBytes(attachment.size * 1024, "0 KB")].filter(Boolean).join(" · ");
+		const detail = [attachment.format, attachment.size == null ? "" : formatBytes(attachment.size * 1024)].filter(Boolean).join(" · ");
 		if (detail) {
 			const meta = document.createElement("span");
 			meta.className = "attachment-detail";
@@ -3524,9 +3525,9 @@ function currentImageDPI() {
 	return Number.parseFloat(el.imageDPI.value) || DEFAULT_IMAGE_DPI;
 }
 
-function formatBytes(size, fallback = "PDF") {
+function formatBytes(size) {
 	if (!Number.isFinite(size) || size <= 0) {
-		return fallback;
+		return "0 KB";
 	}
 	if (size < 1024 * 1024) {
 		return `${Math.round(size / 1024)} KB`;

internal/webui/webui.go

@@ -179,7 +179,8 @@ var supportedExportFormats = []ExportFormat{
 	{Value: "pdf", Label: "PDF", Extension: "pdf", MIME: "application/pdf"},
 	{Value: "eps", Label: "EPS", Extension: "eps", MIME: "application/postscript"},
 	{Value: "png", Label: "PNG", Extension: "png", MIME: "image/png"},
-	{Value: "jpg", Label: "JPEG", Extension: "jpg", MIME: "image/jpeg"},
+	{Value: "jpg", Label: "JPG", Extension: "jpg", MIME: "image/jpeg"},
+	{Value: "txt", Label: "TXT", Extension: "txt", MIME: "text/plain"},
 }
 
 // ExportFormats 获取导出格式
@@ -631,7 +632,7 @@ func signatureStampInfos(positions []ofdgo.SignatureStampPosition) []SignatureSt
 	return infos
 }
 
-// ExportDocument 导出文档为PDF或逐页打包ZIP
+// ExportDocument 导出文档为PDF、TXT或逐页打包ZIP
 // 入参: value 导出格式, dpi 图片DPI, writer 输出流, indices 零基页面索引，省略则全部
 // 返回: ExportFormat 导出格式, error 错误信息
 func (s *Session) ExportDocument(value string, dpi float64, writer io.Writer, indices ...int) (ExportFormat, error) {
@@ -645,6 +646,9 @@ func (s *Session) ExportDocument(value string, dpi float64, writer io.Writer, in
 	if s == nil || s.Reader == nil || s.Renderer == nil || s.doc == nil {
 		return ExportFormat{}, fmt.Errorf("ofd document is not opened")
 	}
+	if format.Value == "txt" {
+		return format, s.Renderer.RenderToMultiPageText(writer, indices...)
+	}
 	renderer := *s.Renderer
 	if dpi > 0 && (format.Value == "png" || format.Value == "jpg") {
 		renderer.DPI = dpi

ofdgo_renderer_output.go

@@ -36,7 +36,7 @@ import (
 )
 
 // RenderTo 按格式渲染单页，JPEG使用95画质
-// 入参: page 页面内容, writer 输出流, format svg、pdf、eps、png、jpg或jpeg
+// 入参: page 页面内容, writer 输出流, format svg、pdf、eps、png、jpg、jpeg或txt
 // 返回: error 错误信息
 func (r *Renderer) RenderTo(page *PageContent, writer io.Writer, format string) error {
 	_, render, err := r.outputRenderer(format)
@@ -55,6 +55,8 @@ func (r *Renderer) outputRenderer(format string) (string, func(*PageContent, io.
 		return "svg", r.RenderToSVG, nil
 	case "pdf":
 		return "pdf", r.RenderToPDF, nil
+	case "txt":
+		return "txt", r.RenderToText, nil
 	case "eps":
 		return "eps", r.RenderToEPS, nil
 	case "png":
@@ -69,7 +71,7 @@ func (r *Renderer) outputRenderer(format string) (string, func(*PageContent, io.
 }
 
 // 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
-// 入参: writer 输出流, format svg、pdf、eps、png、jpg或jpeg, indices 零基页面索引，省略则全部，按原页序去重
+// 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 {
 	extension, render, err := r.outputRenderer(format)
@@ -115,6 +117,61 @@ func (r *Renderer) RenderToZIP(writer io.Writer, format string, indices ...int)
 	return archive.Close()
 }
 
+// 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)
+	if err != nil {
+		return err
+	}
+	_, err = io.WriteString(writer, text.String())
+	return 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()
+	if err != nil {
+		return err
+	}
+	indices, err = exportPageIndices(count, indices)
+	if err != nil {
+		return err
+	}
+	if err := r.exportProgress(0, len(indices)); err != nil {
+		return err
+	}
+	written := false
+	for i, index := range indices {
+		page, err := r.Reader.PageContentByIndex(index)
+		if err != nil {
+			return fmt.Errorf("failed to read page %d: %w", index+1, err)
+		}
+		text, err := r.PageText(page)
+		if err != nil {
+			return fmt.Errorf("failed to extract page %d text: %w", index+1, err)
+		}
+		if value := text.String(); value != "" {
+			if written {
+				if _, err := io.WriteString(writer, "\n"); err != nil {
+					return err
+				}
+			}
+			if _, err := io.WriteString(writer, value); err != nil {
+				return err
+			}
+			written = true
+		}
+		if err := r.exportProgress(i+1, len(indices)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // exportProgress 回报导出进度并传递调用方的停止原因
 // 入参: completed 已处理页数, total 总页数
 // 返回: error 停止原因