940a406dce
Backup commit before executing remove-unused-code proposal. This includes all pending changes and new features. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
142 lines
3.5 KiB
Markdown
142 lines
3.5 KiB
Markdown
# Design: Simple Text Positioning
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## Architecture
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### Current Flow (Complex)
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```
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Raw OCR → PP-Structure Analysis → Table Detection → HTML Parsing →
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Column Correction → Cell Positioning → PDF Generation
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```
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### New Flow (Simple)
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```
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Raw OCR → Text Region Extraction → Bbox Processing →
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Rotation Calculation → Font Size Estimation → PDF Text Rendering
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```
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## Core Components
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### 1. TextRegionRenderer
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New service class to handle raw OCR text rendering:
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```python
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class TextRegionRenderer:
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"""Render raw OCR text regions to PDF."""
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def render_text_region(
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self,
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canvas: Canvas,
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region: Dict,
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scale_factor: float
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) -> None:
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"""
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Render a single OCR text region.
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Args:
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canvas: ReportLab canvas
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region: Raw OCR region with text and bbox
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scale_factor: Coordinate scaling factor
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"""
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```
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### 2. Bbox Processing
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Raw OCR bbox format (quadrilateral - 4 corner points):
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```json
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{
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"text": "LOCTITE",
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"bbox": [[116, 76], [378, 76], [378, 128], [116, 128]],
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"confidence": 0.98
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}
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```
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Processing steps:
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1. **Center point**: Average of 4 corners
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2. **Width/Height**: Distance between corners
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3. **Rotation angle**: Angle of top edge from horizontal
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4. **Font size**: Approximate from bbox height
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### 3. Rotation Calculation
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```python
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def calculate_rotation(bbox: List[List[float]]) -> float:
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"""
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Calculate text rotation from bbox quadrilateral.
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Returns angle in degrees (counter-clockwise from horizontal).
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"""
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# Top-left to top-right vector
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dx = bbox[1][0] - bbox[0][0]
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dy = bbox[1][1] - bbox[0][1]
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# Angle in degrees
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angle = math.atan2(dy, dx) * 180 / math.pi
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return angle
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```
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### 4. Font Size Estimation
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```python
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def estimate_font_size(bbox: List[List[float]], text: str) -> float:
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"""
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Estimate font size from bbox dimensions.
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Uses bbox height as primary indicator, adjusted for aspect ratio.
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"""
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# Calculate bbox height (average of left and right edges)
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left_height = math.dist(bbox[0], bbox[3])
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right_height = math.dist(bbox[1], bbox[2])
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avg_height = (left_height + right_height) / 2
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# Font size is approximately 70-80% of bbox height
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return avg_height * 0.75
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```
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## Integration Points
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### PDFGeneratorService
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Modify `draw_ocr_content()` to use simple text positioning:
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```python
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def draw_ocr_content(self, canvas, content_data, page_info):
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"""Draw OCR content using simple text positioning."""
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# Use raw OCR regions directly
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raw_regions = content_data.get('raw_ocr_regions', [])
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for region in raw_regions:
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self.text_renderer.render_text_region(
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canvas, region, scale_factor
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)
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```
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### Configuration
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Add config option to enable/disable simple mode:
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```python
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class OCRSettings:
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simple_text_positioning: bool = Field(
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default=True,
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description="Use simple text positioning instead of table reconstruction"
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)
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```
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## File Changes
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| File | Change |
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|------|--------|
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| `app/services/text_region_renderer.py` | New - Text rendering logic |
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| `app/services/pdf_generator_service.py` | Modify - Integration |
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| `app/core/config.py` | Add - Configuration option |
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## Edge Cases
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1. **Overlapping text**: Regions may overlap slightly - render in reading order
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2. **Very small text**: Minimum font size threshold (6pt)
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3. **Rotated pages**: Handle 90/180/270 degree page rotation
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4. **Empty regions**: Skip regions with empty text
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5. **Unicode text**: Ensure font supports CJK characters
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