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feat: implement proper track-specific PDF rendering

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Implement independent Direct and OCR track rendering methods with
complete separation of concerns and proper line break handling.

**Architecture Changes**:
- Created _generate_direct_track_pdf() for rich formatting
- Created _generate_ocr_track_pdf() for backward compatible rendering
- Modified generate_from_unified_document() to route by track type
- No more shared rendering path that loses information

**Direct Track Features** (_generate_direct_track_pdf):
- Processes UnifiedDocument directly (no legacy conversion)
- Preserves all StyleInfo without information loss
- Handles line breaks (\n) in text content
- Layer-based rendering: images → tables → text
- Three specialized helper methods:
  - _draw_text_element_direct(): Multi-line text with styling
  - _draw_table_element_direct(): Direct bbox table rendering
  - _draw_image_element_direct(): Image positioning from bbox

**OCR Track Features** (_generate_ocr_track_pdf):
- Uses legacy OCR data conversion pipeline
- Routes to existing _generate_pdf_from_data()
- Maintains full backward compatibility
- Simplified rendering for OCR-detected layout

**Line Break Handling** (Direct Track):
- Split text on '\n' into multiple lines
- Calculate line height as font_size * 1.2
- Render each line with proper vertical spacing
- Font scaling per line if width exceeds bbox

**Implementation Details**:
Lines 535-569: Track detection and routing
Lines 571-670: _generate_direct_track_pdf() main method
Lines 672-717: _generate_ocr_track_pdf() main method
Lines 1497-1575: _draw_text_element_direct() with line breaks
Lines 1577-1656: _draw_table_element_direct()
Lines 1658-1714: _draw_image_element_direct()

**Corrected Task Status**:
- Task 4.2: NOW properly implements separate Direct track pipeline
- Task 4.3: NOW properly implements separate OCR track pipeline
- Both with distinct rendering logic as designed

**Breaking vs Previous Commit**:
Previous commit (3fc32bc) only added conditional styling in shared
draw_text_region(). This commit creates true track-specific pipelines
as per design.md requirements.

Direct track PDFs will now:
✅ Process without legacy conversion (no info loss)
✅ Render multi-line text properly (split on \n)
✅ Apply StyleInfo per element
✅ Use precise bbox positioning
✅ Render images and tables directly

OCR track PDFs will:
✅ Use existing proven pipeline
✅ Maintain backward compatibility
✅ No changes to current behavior

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
egg
2025-11-24 07:53:17 +08:00
parent 3fc32bcdd7
commit 09cf9149ce
2 changed files with 393 additions and 19 deletions
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389
backend/app/services/pdf_generator_service.py
View File

@@ -534,31 +534,183 @@ class PDFGeneratorService:
try:
# Detect processing track for track-specific rendering
self.current_processing_track = None
processing_track = None
if hasattr(unified_doc, 'metadata') and unified_doc.metadata:
if hasattr(unified_doc.metadata, 'processing_track'):
self.current_processing_track = unified_doc.metadata.processing_track
logger.info(f"Processing track detected: {self.current_processing_track}")
processing_track = unified_doc.metadata.processing_track
elif isinstance(unified_doc.metadata, dict):
self.current_processing_track = unified_doc.metadata.get('processing_track')
logger.info(f"Processing track detected: {self.current_processing_track}")
processing_track = unified_doc.metadata.get('processing_track')
# Convert UnifiedDocument to OCR data format
# Route to track-specific rendering method
is_direct_track = (processing_track == 'direct' or
processing_track == ProcessingTrack.DIRECT)
logger.info(f"Processing track: {processing_track}, using {'Direct' if is_direct_track else 'OCR'} track rendering")
if is_direct_track:
# Direct track: Rich formatting preservation
return self._generate_direct_track_pdf(
unified_doc=unified_doc,
output_path=output_path,
source_file_path=source_file_path
)
else:
# OCR track: Simplified rendering (backward compatible)
return self._generate_ocr_track_pdf(
unified_doc=unified_doc,
output_path=output_path,
source_file_path=source_file_path
)
except Exception as e:
logger.error(f"Failed to generate PDF from UnifiedDocument: {e}")
import traceback
traceback.print_exc()
return False
def _generate_direct_track_pdf(
self,
unified_doc: 'UnifiedDocument',
output_path: Path,
source_file_path: Optional[Path] = None
) -> bool:
"""
Generate PDF with rich formatting preservation for Direct track.
This method processes UnifiedDocument directly without converting to
legacy OCR format, preserving StyleInfo and applying proper text
formatting including line breaks.
Args:
unified_doc: UnifiedDocument from Direct extraction
output_path: Path to save generated PDF
source_file_path: Optional path to original source file
Returns:
True if successful, False otherwise
"""
try:
logger.info("=== Direct Track PDF Generation ===")
logger.info(f"Total pages: {len(unified_doc.pages)}")
# Set current track for helper methods
self.current_processing_track = 'direct'
# Get page dimensions from first page
if not unified_doc.pages:
logger.error("No pages in document")
return False
first_page = unified_doc.pages[0]
page_width = first_page.width
page_height = first_page.height
logger.info(f"Page dimensions: {page_width} x {page_height}")
# Create PDF canvas with source dimensions
from reportlab.pdfgen import canvas
pdf_canvas = canvas.Canvas(str(output_path), pagesize=(page_width, page_height))
# Process each page
for page_idx, page in enumerate(unified_doc.pages):
logger.info(f">>> Processing page {page_idx + 1}/{len(unified_doc.pages)}")
if page_idx > 0:
pdf_canvas.showPage()
# Separate elements by type
text_elements = []
table_elements = []
image_elements = []
for element in page.elements:
if element.type == ElementType.TABLE:
table_elements.append(element)
elif element.is_visual or element.type in [
ElementType.IMAGE, ElementType.FIGURE,
ElementType.CHART, ElementType.DIAGRAM
]:
image_elements.append(element)
elif element.is_text or element.type in [
ElementType.TEXT, ElementType.TITLE, ElementType.HEADER,
ElementType.FOOTER, ElementType.PARAGRAPH
]:
text_elements.append(element)
logger.info(f"Page {page_idx + 1}: {len(text_elements)} text, "
f"{len(table_elements)} tables, {len(image_elements)} images")
# Draw in layers: images → tables → text
# 1. Draw images
for img_elem in image_elements:
self._draw_image_element_direct(pdf_canvas, img_elem, page_height, output_path.parent)
# 2. Draw tables
for table_elem in table_elements:
self._draw_table_element_direct(pdf_canvas, table_elem, page_height)
# 3. Draw text with line breaks and styling
for text_elem in text_elements:
self._draw_text_element_direct(pdf_canvas, text_elem, page_height)
# Save PDF
pdf_canvas.save()
logger.info(f"Direct track PDF saved to {output_path}")
# Reset track
self.current_processing_track = None
return True
except Exception as e:
logger.error(f"Failed to generate Direct track PDF: {e}")
import traceback
traceback.print_exc()
self.current_processing_track = None
return False
def _generate_ocr_track_pdf(
self,
unified_doc: 'UnifiedDocument',
output_path: Path,
source_file_path: Optional[Path] = None
) -> bool:
"""
Generate PDF with simplified rendering for OCR track.
This method uses the existing OCR data conversion and rendering
pipeline for backward compatibility.
Args:
unified_doc: UnifiedDocument from OCR processing
output_path: Path to save generated PDF
source_file_path: Optional path to original source file
Returns:
True if successful, False otherwise
"""
try:
logger.info("=== OCR Track PDF Generation ===")
# Set current track
self.current_processing_track = 'ocr'
# Convert UnifiedDocument to OCR data format (legacy)
ocr_data = self.convert_unified_document_to_ocr_data(unified_doc)
# Use internal generation with pre-loaded data
# Use existing generation pipeline
result = self._generate_pdf_from_data(
ocr_data=ocr_data,
output_path=output_path,
source_file_path=source_file_path
)
# Reset track after generation
# Reset track
self.current_processing_track = None
return result
except Exception as e:
logger.error(f"Failed to generate PDF from UnifiedDocument: {e}")
logger.error(f"Failed to generate OCR track PDF: {e}")
import traceback
traceback.print_exc()
self.current_processing_track = None
@@ -1342,6 +1494,225 @@ class PDFGeneratorService:
traceback.print_exc()
return False
def _draw_text_element_direct(
self,
pdf_canvas: canvas.Canvas,
element: 'DocumentElement',
page_height: float
):
"""
Draw text element with Direct track rich formatting.
Handles line breaks, applies StyleInfo, and preserves text positioning.
Args:
pdf_canvas: ReportLab canvas object
element: DocumentElement with text content
page_height: Page height for coordinate transformation
"""
try:
text_content = element.get_text()
if not text_content:
return
# Get bounding box
bbox = element.bbox
if not bbox:
logger.warning(f"No bbox for text element {element.element_id}")
return
# Transform coordinates (top-left origin → bottom-left origin)
pdf_x = bbox.x0
pdf_y = page_height - bbox.y1 # Use bottom of bbox
bbox_width = bbox.x1 - bbox.x0
bbox_height = bbox.y1 - bbox.y0
# Calculate font size from bbox height
font_size = bbox_height * 0.75
font_size = max(min(font_size, 72), 4) # Clamp 4-72pt
# Apply style if available
if hasattr(element, 'style') and element.style:
self._apply_text_style(pdf_canvas, element.style, default_size=font_size)
else:
# Use default font
font_name = self.font_name if self.font_registered else 'Helvetica'
pdf_canvas.setFont(font_name, font_size)
# Handle line breaks
lines = text_content.split('\n')
line_height = font_size * 1.2 # 120% of font size
# Draw each line
for i, line in enumerate(lines):
if not line.strip():
continue
line_y = pdf_y - (i * line_height)
# Check if text fits in bbox width
font_name = pdf_canvas._fontname
text_width = pdf_canvas.stringWidth(line, font_name, font_size)
if text_width > bbox_width:
# Scale down font to fit
scale_factor = bbox_width / text_width
scaled_size = font_size * scale_factor * 0.95
scaled_size = max(scaled_size, 3)
pdf_canvas.setFont(font_name, scaled_size)
# Draw the line
pdf_canvas.drawString(pdf_x, line_y, line)
# Reset font size for next line
if text_width > bbox_width:
pdf_canvas.setFont(font_name, font_size)
logger.debug(f"Drew text element: {text_content[:30]}... ({len(lines)} lines)")
except Exception as e:
logger.error(f"Failed to draw text element {element.element_id}: {e}")
def _draw_table_element_direct(
self,
pdf_canvas: canvas.Canvas,
element: 'DocumentElement',
page_height: float
):
"""
Draw table element with Direct track positioning.
Args:
pdf_canvas: ReportLab canvas object
element: DocumentElement with table content
page_height: Page height for coordinate transformation
"""
try:
# Get table HTML content
if isinstance(element.content, TableData):
html_content = element.content.to_html()
elif isinstance(element.content, dict):
html_content = element.content.get('html', str(element.content))
else:
html_content = str(element.content)
if not html_content:
logger.warning(f"No HTML content for table {element.element_id}")
return
# Parse HTML
parser = HTMLTableParser()
parser.feed(html_content)
if not parser.tables or not parser.tables[0]['rows']:
logger.warning(f"No table data parsed for {element.element_id}")
return
table_data = parser.tables[0]
rows = table_data['rows']
# Get bbox
bbox = element.bbox
if not bbox:
logger.warning(f"No bbox for table {element.element_id}")
return
# Transform coordinates
pdf_x = bbox.x0
pdf_y = page_height - bbox.y1 # Bottom of table
table_width = bbox.x1 - bbox.x0
table_height = bbox.y1 - bbox.y0
# Build table data for ReportLab
table_content = []
for row in rows:
row_data = [cell['text'].strip() for cell in row['cells']]
table_content.append(row_data)
# Create table
from reportlab.platypus import Table, TableStyle
from reportlab.lib import colors
t = Table(table_content, colWidths=[table_width / len(table_content[0])] * len(table_content[0]))
# Apply style
style = TableStyle([
('GRID', (0, 0), (-1, -1), 0.5, colors.grey),
('FONTSIZE', (0, 0), (-1, -1), 8),
('ALIGN', (0, 0), (-1, -1), 'LEFT'),
('VALIGN', (0, 0), (-1, -1), 'TOP'),
])
t.setStyle(style)
# Draw table
t.wrapOn(pdf_canvas, table_width, table_height)
t.drawOn(pdf_canvas, pdf_x, pdf_y)
logger.debug(f"Drew table element: {len(rows)} rows")
except Exception as e:
logger.error(f"Failed to draw table element {element.element_id}: {e}")
def _draw_image_element_direct(
self,
pdf_canvas: canvas.Canvas,
element: 'DocumentElement',
page_height: float,
result_dir: Path
):
"""
Draw image element with Direct track positioning.
Args:
pdf_canvas: ReportLab canvas object
element: DocumentElement with image content
page_height: Page height for coordinate transformation
result_dir: Directory containing image files
"""
try:
# Get image path
image_path_str = self._get_image_path(element)
if not image_path_str:
logger.warning(f"No image path for element {element.element_id}")
return
# Construct full path
image_path = result_dir / image_path_str
if not image_path.exists():
logger.warning(f"Image not found: {image_path}")
return
# Get bbox
bbox = element.bbox
if not bbox:
logger.warning(f"No bbox for image {element.element_id}")
return
# Transform coordinates
pdf_x = bbox.x0
pdf_y = page_height - bbox.y1 # Bottom of image
image_width = bbox.x1 - bbox.x0
image_height = bbox.y1 - bbox.y0
# Draw image
pdf_canvas.drawImage(
str(image_path),
pdf_x,
pdf_y,
width=image_width,
height=image_height,
preserveAspectRatio=True
)
logger.debug(f"Drew image: {image_path_str}")
except Exception as e:
logger.error(f"Failed to draw image element {element.element_id}: {e}")
# Singleton instance
pdf_generator_service = PDFGeneratorService()

23
openspec/changes/pdf-layout-restoration/tasks.md
View File

@@ -57,16 +57,19 @@
### 4. Track-Specific Rendering
- [x] 4.1 Add track detection in generate_from_unified_document
- [x] 4.1.1 Check unified_doc.metadata.processing_track (object and dict support)
- [x] 4.1.2 Store in self.current_processing_track for rendering methods
- [x] 4.2 Apply StyleInfo for Direct track
- [x] 4.2.1 Preserve style information in convert_unified_document_to_ocr_data
- [x] 4.2.2 Apply StyleInfo to text elements in draw_text_region
- [x] 4.2.3 Use precise positioning (existing implementation maintained)
- [x] 4.2.4 Track detection in draw_text_region (is_direct_track check)
- [x] 4.3 Simplified rendering for OCR track
- [x] 4.3.1 Use simple font selection when not Direct track
- [x] 4.3.2 Best-effort positioning (existing implementation)
- [x] 4.3.3 Estimated font sizes (bbox height-based heuristic)
- [x] 4.1.2 Route to _generate_direct_track_pdf or _generate_ocr_track_pdf
- [x] 4.2 Implement _generate_direct_track_pdf
- [x] 4.2.1 Process each page directly from UnifiedDocument (no legacy conversion)
- [x] 4.2.2 Apply StyleInfo to text elements (_draw_text_element_direct)
- [x] 4.2.3 Use precise positioning from element.bbox
- [x] 4.2.4 Preserve line breaks (split on \n, render multi-line)
- [x] 4.2.5 Implement _draw_text_element_direct with line break handling
- [x] 4.2.6 Implement _draw_table_element_direct for tables
- [x] 4.2.7 Implement _draw_image_element_direct for images
- [x] 4.3 Implement _generate_ocr_track_pdf
- [x] 4.3.1 Use legacy OCR data conversion (convert_unified_document_to_ocr_data)
- [x] 4.3.2 Route to existing _generate_pdf_from_data pipeline
- [x] 4.3.3 Maintain backward compatibility with OCR track behavior
- [ ] 4.4 Test track-specific rendering
- [ ] 4.4.1 Compare Direct track with original
- [ ] 4.4.2 Verify OCR track maintains quality