# Result Export Spec Delta

## MODIFIED Requirements

### Requirement: Export Interface
The Export page SHALL support downloading OCR results in multiple formats using V2 task APIs, with processing track information and enhanced structure data.

#### Scenario: Export page uses V2 download endpoints
- **WHEN** user selects a format and clicks export button
- **THEN** frontend SHALL call V2 endpoint `/api/v2/tasks/{task_id}/download/{format}`
- **AND** frontend SHALL NOT call V1 `/api/v2/export` endpoint (which returns 404)
- **AND** file SHALL download successfully

#### Scenario: Export supports multiple formats
- **WHEN** user exports a completed task
- **THEN** system SHALL support downloading as TXT, JSON, Excel, Markdown, and PDF
- **AND** each format SHALL use correct V2 download endpoint
- **AND** downloaded files SHALL contain task OCR results

#### Scenario: Export includes processing track metadata
- **WHEN** user exports a task processed through dual-track system
- **THEN** exported JSON SHALL include "processing_track" field indicating "ocr" or "direct"
- **AND** SHALL include "processing_metadata" with track-specific information
- **AND** SHALL maintain backward compatibility for clients not expecting these fields

#### Scenario: Export UnifiedDocument format
- **WHEN** user requests JSON export with unified=true parameter
- **THEN** system SHALL return UnifiedDocument structure
- **AND** include complete element hierarchy with coordinates
- **AND** preserve all PP-StructureV3 element types for OCR track

## ADDED Requirements

### Requirement: Enhanced PDF Export with Layout Preservation
The PDF export SHALL accurately preserve document layout from both OCR and direct extraction tracks.

#### Scenario: Export PDF from direct extraction track
- **WHEN** exporting PDF from a direct-extraction processed document
- **THEN** the PDF SHALL maintain exact text positioning from source
- **AND** preserve original fonts and styles where possible
- **AND** include extracted images at correct positions

#### Scenario: Export PDF from OCR track with full structure
- **WHEN** exporting PDF from OCR-processed document
- **THEN** the PDF SHALL use all 23 PP-StructureV3 element types
- **AND** render tables with proper cell boundaries
- **AND** maintain reading order from parsing_res_list

#### Scenario: Handle coordinate transformations
- **WHEN** generating PDF from UnifiedDocument
- **THEN** system SHALL correctly transform bbox coordinates to PDF space
- **AND** handle page size variations
- **AND** prevent text overlap using enhanced overlap detection

### Requirement: Structure Data Export
The system SHALL provide export formats that preserve document structure for downstream processing.

#### Scenario: Export structured JSON with hierarchy
- **WHEN** user selects structured JSON format
- **THEN** export SHALL include element hierarchy and relationships
- **AND** preserve parent-child relationships (sections, lists)
- **AND** include style and formatting information

#### Scenario: Export for translation preparation
- **WHEN** user exports with translation_ready=true parameter
- **THEN** export SHALL include translatable text segments
- **AND** maintain coordinate mappings for each segment
- **AND** mark non-translatable regions

#### Scenario: Export with layout analysis
- **WHEN** user requests layout analysis export
- **THEN** system SHALL include reading order indices
- **AND** identify layout regions (header, body, footer, sidebar)
- **AND** provide confidence scores for layout detection