# Implementation Tasks

## 1. Fix Page Dimension Calculation
- [ ] 1.1 Modify `calculate_page_dimensions()` in `pdf_generator_service.py`
  - [ ] Add priority check for `ocr_dimensions` field first
  - [ ] Add fallback check for `dimensions` field
  - [ ] Keep bbox calculation as final fallback only
  - [ ] Add logging to show which dimension source is used
- [ ] 1.2 Add unit tests for dimension calculation logic
  - [ ] Test with explicit dimensions provided
  - [ ] Test with missing dimensions (fallback to bbox)
  - [ ] Test edge cases (empty content, single element)

## 2. Implement Dynamic Per-Page Sizing for Direct Track
- [ ] 2.1 Refactor `_generate_direct_track_pdf()` loop
  - [ ] Extract current page dimensions inside loop
  - [ ] Call `pdf_canvas.setPageSize()` for each page
  - [ ] Pass current `page_height` to all drawing functions
- [ ] 2.2 Update drawing helper functions
  - [ ] Ensure `_draw_text_element_direct()` receives `page_height` parameter
  - [ ] Ensure `_draw_image_element()` receives `page_height` parameter
  - [ ] Ensure `_draw_table_element()` receives `page_height` parameter

## 3. Implement Dynamic Per-Page Sizing for OCR Track
- [ ] 3.1 Enhance `convert_unified_document_to_ocr_data()`
  - [ ] Add `page_dimensions` field to output dict
  - [ ] Map each page index to its dimensions: `{0: {width: X, height: Y}, ...}`
  - [ ] Include `ocr_dimensions` field for backward compatibility
- [ ] 3.2 Refactor `_generate_ocr_track_pdf()` loop
  - [ ] Read dimensions from `page_dimensions[page_num]`
  - [ ] Call `pdf_canvas.setPageSize()` for each page
  - [ ] Pass current `page_height` to coordinate transformation

## 4. Testing & Validation
- [ ] 4.1 Single-page layout verification
  - [ ] Process `img1.png` through OCR track
  - [ ] Verify generated PDF text positions match original image
  - [ ] Confirm no vertical flipping or offset issues
  - [ ] Check "D" header appears at correct top position
- [ ] 4.2 Multi-page mixed orientation test
  - [ ] Create test PDF with portrait and landscape pages
  - [ ] Process through both OCR and Direct tracks
  - [ ] Verify each page uses correct dimensions
  - [ ] Confirm no content clipping or misalignment
- [ ] 4.3 Regression testing
  - [ ] Run existing PDF generation tests
  - [ ] Verify Direct track StyleInfo preservation
  - [ ] Check table rendering still works correctly
  - [ ] Ensure image extraction positions are correct

## 5. Documentation
- [ ] 5.1 Update code comments in `pdf_generator_service.py`
- [ ] 5.2 Document coordinate transformation logic
- [ ] 5.3 Add inline examples for multi-page handling