add documentation and update readme.
fix extraction issues. Add test param.
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README.md
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README.md
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# PDF Highlight Extractor
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A Python tool for extracting highlighted text from PDF files with precise text ordering and intelligent hyphenation handling.
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## Features
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- **4-Color Support**: Extracts Yellow, Pink, Green, and Blue highlights
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- **Smart Text Ordering**: Fixes PDF text extraction order issues using multiple methods
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- **Hyphenation Merging**: Automatically combines hyphenated words across lines ("lin-" + "guistics" → "linguistics")
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- **Precise Boundaries**: Configurable overlap detection to avoid over-extraction
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- **Multiple Extraction Methods**: Fallback system for maximum compatibility
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- **Cross-page Support**: Handles highlights that span multiple pages
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- **Test Mode**: Quick testing with default settings
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- **Export Options**: JSON and CSV output formats
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## Installation
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Clone the repository:
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git clone <repository-url>
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cd pdf-highlight-extractor
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Install required packages:
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pip install PyMuPDF pdfplumber colorama pandas
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## Dependencies
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- PyMuPDF (fitz) - PDF processing and text extraction
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- pdfplumber - Additional PDF annotation support
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- colorama - Colored terminal output
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- pandas - CSV export functionality
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## Usage
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### Quick Test Mode
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python highlight_extractor.py --test
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Uses default file: `/mnt/c/Users/admin/Downloads/test2.pdf` and displays results only.
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### Interactive Mode
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python highlight_extractor.py
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Prompts for PDF file path and output options.
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### Command Line Flags
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- `--test`, `-t`, or `test` - Enable test mode with defaults
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- No flags - Full interactive mode
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## Output Formats
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### Terminal Display
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📄 Page 35
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🎨 YELLOW
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"We end with some specific suggestions for what we can do as linguists"
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🎨 PINK (hyphen-merged)
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"linguistics itself"
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### JSON Export
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{
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"highlights": [
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{
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"page": 35,
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"text": "We end with some specific suggestions",
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"color": "yellow",
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"type": "highlight"
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}
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]
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}
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### CSV Export
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Tabular format with columns: page, text, color, type, category
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## Technical Features
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### Text Ordering Algorithm
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1. **Method A**: PyMuPDF built-in sorting
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2. **Method B**: Text block extraction with geometric sorting
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3. **Method C**: Enhanced word-level sorting with line detection
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### Hyphenation Detection
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- Same-page: Detects hyphens within 8-30 pixel line spacing
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- Cross-page: Handles hyphenation across page boundaries
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- Smart merging: Only merges clear hyphenation patterns
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### Precision Control
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- **Overlap Threshold**: 40% word overlap required for inclusion
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- **Boundary Expansion**: +2 pixel expansion for edge words
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- **Line Tolerance**: 5-pixel tolerance for same-line detection
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## Troubleshooting
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### Common Issues
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**Text Order Problems**: The tool uses multiple methods to fix PDF text ordering issues. If text still appears scrambled, the PDF may have complex layout encoding.
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**Missing Words**: Lower the overlap threshold or check if highlights are too light/transparent.
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**Over-extraction**: The tool is designed to avoid this, but very close text might be included. Check highlight precision in your PDF.
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### Debug Output
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Run with detailed logging to see extraction decisions:
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python highlight_extractor.py --test
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## Contributing
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1. Create a feature branch from main
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2. Make your changes
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3. Test with sample PDFs
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4. Submit a pull request
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## License
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MIT License
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## Support
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For issues or questions, please open a GitHub issue.
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# PDF Highlight Extraction Process - Step by Step
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## Phase 1: Initialization and Setup
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1. **Script Startup**: Check command line arguments for test mode
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2. **Path Resolution**: Determine PDF file path (default or user input)
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3. **File Validation**: Verify PDF file exists and is accessible
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4. **Object Creation**: Initialize PDFHighlightExtractor with file path
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## Phase 2: PDF Analysis and Loading
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1. **Document Opening**: Load PDF using PyMuPDF (fitz) library
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2. **Page Iteration**: Loop through each page in the document
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3. **Annotation Discovery**: Find all annotations on each page
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4. **Type Filtering**: Identify highlight-type annotations specifically
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## Phase 3: Color Classification
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1. **Color Extraction**: Get RGB values from annotation properties
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2. **Color Normalization**: Convert to 0-255 range if needed
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3. **Color Mapping**: Classify into 4 categories (Yellow, Pink, Green, Blue)
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4. **Unknown Filtering**: Skip annotations with unrecognized colors
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## Phase 4: Text Extraction (Multi-Method Approach)
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### Method A: Built-in Sorting
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1. **Rectangle Expansion**: Add 2-pixel buffer around highlight area
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2. **PyMuPDF Extraction**: Use page.get_text("text", sort=True)
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3. **Text Cleaning**: Remove extra whitespace and normalize
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4. **Success Check**: Return if valid text found
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### Method B: Text Block Extraction
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1. **Block Discovery**: Get text blocks from highlight area
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2. **Geometric Sorting**: Sort blocks by Y-position, then X-position
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3. **Block Combination**: Join block texts with spaces
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4. **Quality Check**: Verify result makes sense
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### Method C: Enhanced Word Sorting
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1. **Word Collection**: Get all words intersecting highlight area
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2. **Overlap Calculation**: Calculate intersection ratio for each word
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3. **Threshold Filtering**: Include words with 40%+ overlap
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4. **Line Detection**: Group words by Y-position (5-pixel tolerance)
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5. **Line Sorting**: Sort lines top-to-bottom
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6. **Word Sorting**: Sort words left-to-right within each line
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7. **Text Assembly**: Combine words in proper reading order
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## Phase 5: Hyphenation Detection and Merging
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1. **Pattern Recognition**: Look for highlights ending with '-'
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2. **Proximity Check**: Verify next highlight is same color and nearby
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3. **Distance Validation**: Check reasonable line spacing (8-30 pixels)
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4. **Page Handling**: Support both same-page and cross-page hyphenation
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5. **Text Joining**: Remove hyphen and combine words seamlessly
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## Phase 6: Data Organization
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1. **Highlight Storage**: Create structured data objects for each highlight
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2. **Sorting**: Order by page number, then Y-position, then X-position
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3. **Merging**: Apply hyphenation merging where detected
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4. **Categorization**: Separate annotations from background highlights
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## Phase 7: Output Generation
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### Terminal Display
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1. **Page Grouping**: Organize results by page number
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2. **Color Coding**: Apply terminal colors for visual distinction
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3. **Status Indicators**: Show merge status (hyphen-merged, cross-page)
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4. **Formatting**: Clean, readable text presentation
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### File Export (Optional)
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1. **JSON Generation**: Structure data with metadata
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2. **CSV Creation**: Tabular format for analysis
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3. **File Writing**: Save to specified output paths
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## Phase 8: Cleanup and Reporting
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1. **Resource Cleanup**: Close PDF document properly
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2. **Statistics**: Report extraction counts and timing
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3. **Status Messages**: Provide user feedback on results
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4. **Memory Management**: Clean up temporary objects
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## Error Handling Throughout
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- **Try-Catch Blocks**: Graceful handling of PDF parsing errors
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- **Fallback Methods**: Alternative extraction approaches
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- **Validation Checks**: Verify data integrity at each step
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- **User Feedback**: Clear error messages and debugging info
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## Debug Information
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- **Overlap Ratios**: Show word inclusion/exclusion decisions
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- **Method Success**: Indicate which extraction method worked
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- **Hyphenation Detection**: Log when word merging occurs
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- **Performance Timing**: Track processing duration
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