feat(能力完善): 完善转换保真，修复交互缺陷

ofdgo_renderer_pdf_attachment.go

@@ -0,0 +1,55 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"maps"
+	"slices"
+
+	"github.com/xiaoqidun/pdfgo"
+)
+
+// writeAttachments 在页面绘制后读取附件，保留文件字节，不自动添加个人信息和时间
+// 入参: ctx 取消上下文, options PDF写出配置
+// 返回: error 附件读取或取消错误
+func (n *pdfNavigation) writeAttachments(ctx context.Context, options *pdfgo.RewriteOptions) error {
+	if len(n.attachments) == 0 {
+		return nil
+	}
+	options.Attachments = make(map[string]*pdfgo.EmbeddedFile, len(n.attachments))
+	for _, id := range slices.Sorted(maps.Keys(n.attachments)) {
+		if err := ctx.Err(); err != nil {
+			return err
+		}
+		attachment := n.attachments[id]
+		input, err := n.source.openFile(n.source.ResPath(attachment.FileLoc))
+		if err != nil {
+			return fmt.Errorf("read attachment %s: %w", id, err)
+		}
+		data, err := io.ReadAll(imageInput{ReadCloser: input, context: ctx})
+		closeErr := input.Close()
+		if err != nil {
+			return fmt.Errorf("read attachment %s: %w", id, err)
+		}
+		if closeErr != nil {
+			return closeErr
+		}
+		options.Attachments[id] = &pdfgo.EmbeddedFile{Name: attachment.FileName(), Data: data}
+	}
+	return ctx.Err()
+}