feat(导出文档): 支持取消导出

ofdgo_renderer_output.go

@@ -90,8 +90,8 @@ func (r *Renderer) RenderToZIP(writer io.Writer, format string, indices ...int)
 		method = zip.Store
 	}
 	width := len(strconv.Itoa(count))
-	if r.OnExportProgress != nil {
-		r.OnExportProgress(0, len(indices))
+	if err := r.exportProgress(0, len(indices)); err != nil {
+		return err
 	}
 	for i, index := range indices {
 		page, err := r.Reader.PageContentByIndex(index)
@@ -108,13 +108,23 @@ 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 r.OnExportProgress != nil {
-			r.OnExportProgress(i+1, len(indices))
+		if err := r.exportProgress(i+1, len(indices)); err != nil {
+			return err
 		}
 	}
 	return archive.Close()
 }
 
+// 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
+func (r *Renderer) exportProgress(completed, total int) error {
+	if r.OnExportProgress != nil {
+		return r.OnExportProgress(completed, total)
+	}
+	return nil
+}
+
 // rasterRenderer 保留页面物理尺寸的光栅渲染器
 type rasterRenderer struct {
 	*rasterizer.Rasterizer
@@ -288,8 +298,8 @@ func (r *Renderer) RenderToMultiPagePDF(writer io.Writer, indices ...int) error
 	if err != nil {
 		return err
 	}
-	if r.OnExportProgress != nil {
-		r.OnExportProgress(0, len(indices))
+	if err := r.exportProgress(0, len(indices)); err != nil {
+		return err
 	}
 	pages := make([]pdfPage, len(indices))
 	for i, index := range indices {
@@ -313,8 +323,8 @@ func (r *Renderer) RenderPagesToPDF(contents []*PageContent, writer io.Writer) e
 	if len(contents) == 0 {
 		return fmt.Errorf("no pages found")
 	}
-	if r.OnExportProgress != nil {
-		r.OnExportProgress(0, len(contents))
+	if err := r.exportProgress(0, len(contents)); err != nil {
+		return err
 	}
 	pages := make([]pdfPage, len(contents))
 	for i, page := range contents {
@@ -330,7 +340,7 @@ func (r *Renderer) RenderPagesToPDF(contents []*PageContent, writer io.Writer) e
 // renderPDFPages 渲染页面并复用调用方的字节缓冲
 // 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 []pdfPage, writer io.Writer, progress func(int, int)) error {
+func (r *Renderer) renderPDFPages(pages []pdfPage, writer io.Writer, progress func(int, int) error) error {
 	navigation := newPDFNavigation(r, r.Reader.doc, pages)
 	buf, direct := writer.(*bytes.Buffer)
 	if !direct {
@@ -354,7 +364,10 @@ func (r *Renderer) renderPDFPages(pages []pdfPage, writer io.Writer, progress fu
 			return fmt.Errorf("failed to render page %d: %w", i+1, err)
 		}
 		if progress != nil {
-			progress(i+1, len(pages))
+			if err := progress(i+1, len(pages)); err != nil {
+				buf.Truncate(start)
+				return err
+			}
 		}
 	}
 	if err := p.Close(); err != nil {