Problem:
- OCR processes images at smaller resolutions but coordinates were being used directly on larger PDF canvases
- This caused all text/tables/images to be drawn at wrong scale in bottom-left corner
Solution:
- Track OCR image dimensions in JSON output (ocr_dimensions)
- Calculate proper scale factors: scale_w = pdf_width/ocr_width, scale_h = pdf_height/ocr_height
- Apply scaling to all coordinates before drawing on PDF canvas
- Support per-page scaling for multi-page PDFs
Changes:
1. ocr_service.py:
- Add OCR image dimensions capture using PIL
- Include ocr_dimensions in JSON output for both single images and PDFs
2. pdf_generator_service.py:
- Calculate scale factors from OCR dimensions vs target PDF dimensions
- Update all drawing methods (text, table, image) to accept and apply scale factors
- Apply scaling to bbox coordinates before coordinate transformation
3. test_pdf_scaling.py:
- Add test script to verify scaling works correctly
- Test with OCR at 500x700 scaled to PDF at 1000x1400 (2x scaling)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
Major Features:
- Add PDF generation service with Chinese font support
- Parse HTML tables from PP-StructureV3 and rebuild with ReportLab
- Extract table text for translation purposes
- Auto-filter text regions inside tables to avoid overlaps
Backend Changes:
1. pdf_generator_service.py (NEW)
- HTMLTableParser: Parse HTML tables to extract structure
- PDFGeneratorService: Generate layout-preserving PDFs
- Coordinate transformation: OCR (top-left) → PDF (bottom-left)
- Font size heuristics: 75% of bbox height with width checking
- Table reconstruction: Parse HTML → ReportLab Table
- Image embedding: Extract bbox from filenames
2. ocr_service.py
- Add _extract_table_text() for translation support
- Add output_dir parameter to save images to result directory
- Extract bbox from image filenames (img_in_table_box_x1_y1_x2_y2.jpg)
3. tasks.py
- Update process_task_ocr to use save_results() with PDF generation
- Fix download_pdf endpoint to use database-stored PDF paths
- Support on-demand PDF generation from JSON
4. config.py
- Add chinese_font_path configuration
- Add pdf_enable_bbox_debug flag
Frontend Changes:
1. PDFViewer.tsx (NEW)
- React PDF viewer with zoom and pagination
- Memoized file config to prevent unnecessary reloads
2. TaskDetailPage.tsx & ResultsPage.tsx
- Integrate PDF preview and download
3. main.tsx
- Configure PDF.js worker via CDN
4. vite.config.ts
- Add host: '0.0.0.0' for network access
- Use VITE_API_URL environment variable for backend proxy
Dependencies:
- reportlab: PDF generation library
- Noto Sans SC font: Chinese character support
🤖 Generated with Claude Code
https://claude.com/claude-code
Co-Authored-By: Claude <noreply@anthropic.com>
