pdf git:20260404.579d601A

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---
name: pdf
description: "Use this skill whenever the user wants to do anything with PDF files. This includes reading or extracting text/tables from PDFs, combining or merging multiple PDFs into one, splitting PDFs apart, rotating pages, adding watermarks, creating new PDFs, filling PDF forms, encrypting/decrypting PDFs, extracting images, and OCR on scanned PDFs to make them searchable. If the user mentions a .pdf file or asks to produce one, use this skill."
dependencies:
  commands:
    - python3
  tools:
    - skillScriptTool
    - skillFileTool
platforms:
  - macos
  - linux
  - windows
---

> **Important:** All `scripts/` paths are relative to this skill directory.
> Use `run_skill_script` tool to execute scripts, or run with: `cd {this_skill_dir} && python scripts/...`

# PDF Processing Guide

## Prerequisites

- **pypdf**: core PDF reading and writing
- **pdfplumber**: text and table extraction
- **reportlab**: PDF creation
- **pdftotext** (poppler-utils): command-line text extraction
- **pdftoppm** (poppler-utils): PDF-to-image conversion
- **qpdf**: PDF manipulation (merge, split, rotate, decrypt)

## Overview

This guide covers essential PDF processing operations using Python libraries and command-line tools.

## Quick Start

```python
from pypdf import PdfReader, PdfWriter

# Read a PDF
reader = PdfReader("document.pdf")
print(f"Pages: {len(reader.pages)}")

# Extract text
text = ""
for page in reader.pages:
    text += page.extract_text()
```

## Python Libraries

### pypdf - Basic Operations

#### Merge PDFs
```python
from pypdf import PdfWriter, PdfReader

writer = PdfWriter()
for pdf_file in ["doc1.pdf", "doc2.pdf", "doc3.pdf"]:
    reader = PdfReader(pdf_file)
    for page in reader.pages:
        writer.add_page(page)

with open("merged.pdf", "wb") as output:
    writer.write(output)
```

#### Split PDF
```python
reader = PdfReader("input.pdf")
for i, page in enumerate(reader.pages):
    writer = PdfWriter()
    writer.add_page(page)
    with open(f"page_{i+1}.pdf", "wb") as output:
        writer.write(output)
```

#### Extract Metadata
```python
reader = PdfReader("document.pdf")
meta = reader.metadata
print(f"Title: {meta.title}")
print(f"Author: {meta.author}")
```

#### Rotate Pages
```python
reader = PdfReader("input.pdf")
writer = PdfWriter()
page = reader.pages[0]
page.rotate(90)  # Rotate 90 degrees clockwise
writer.add_page(page)
with open("rotated.pdf", "wb") as output:
    writer.write(output)
```

### pdfplumber - Text and Table Extraction

#### Extract Text with Layout
```python
import pdfplumber

with pdfplumber.open("document.pdf") as pdf:
    for page in pdf.pages:
        text = page.extract_text()
        print(text)
```

#### Extract Tables
```python
with pdfplumber.open("document.pdf") as pdf:
    for i, page in enumerate(pdf.pages):
        tables = page.extract_tables()
        for j, table in enumerate(tables):
            print(f"Table {j+1} on page {i+1}:")
            for row in table:
                print(row)
```

#### Advanced Table Extraction
```python
import pandas as pd

with pdfplumber.open("document.pdf") as pdf:
    all_tables = []
    for page in pdf.pages:
        tables = page.extract_tables()
        for table in tables:
            if table:
                df = pd.DataFrame(table[1:], columns=table[0])
                all_tables.append(df)

if all_tables:
    combined_df = pd.concat(all_tables, ignore_index=True)
    combined_df.to_excel("extracted_tables.xlsx", index=False)
```

### reportlab - Create PDFs

#### Basic PDF Creation
```python
from reportlab.lib.pagesizes import letter
from reportlab.pdfgen import canvas

c = canvas.Canvas("hello.pdf", pagesize=letter)
width, height = letter
c.drawString(100, height - 100, "Hello World!")
c.line(100, height - 140, 400, height - 140)
c.save()
```

#### Subscripts and Superscripts

**IMPORTANT**: Never use Unicode subscript/superscript characters in ReportLab PDFs. The built-in fonts do not include these glyphs, causing them to render as solid black boxes.

Use ReportLab's XML markup tags instead:
```python
from reportlab.platypus import Paragraph
from reportlab.lib.styles import getSampleStyleSheet
styles = getSampleStyleSheet()
chemical = Paragraph("H<sub>2</sub>O", styles['Normal'])
squared = Paragraph("x<super>2</super> + y<super>2</super>", styles['Normal'])
```

## PDF Form Processing

### Check if PDF has fillable fields
```bash
python scripts/check_fillable_fields.py document.pdf
```

### Extract form field info
```bash
python scripts/extract_form_field_info.py document.pdf
```

### Extract form structure (non-fillable PDFs)
```bash
python scripts/extract_form_structure.py document.pdf
```

### Fill form fields
```bash
python scripts/fill_fillable_fields.py document.pdf output.pdf --fields '{"field_name": "value"}'
```

### Fill with annotations (non-fillable PDFs)
```bash
python scripts/fill_pdf_form_with_annotations.py document.pdf output.pdf --data '{"x,y": "text"}'
```

### Validate bounding boxes
```bash
python scripts/check_bounding_boxes.py document.pdf
```

### Convert PDF to images
```bash
python scripts/convert_pdf_to_images.py document.pdf output_dir/ --dpi 150
```

### Create validation image with overlays
```bash
python scripts/create_validation_image.py document.pdf output.png
```

## Command-Line Tools

### pdftotext (poppler-utils)
```bash
pdftotext input.pdf output.txt              # Extract text
pdftotext -layout input.pdf output.txt      # Preserve layout
pdftotext -f 1 -l 5 input.pdf output.txt   # Pages 1-5
```

### qpdf
```bash
qpdf --empty --pages file1.pdf file2.pdf -- merged.pdf     # Merge
qpdf input.pdf --pages . 1-5 -- pages1-5.pdf               # Split
qpdf input.pdf output.pdf --rotate=+90:1                    # Rotate
qpdf --password=mypassword --decrypt encrypted.pdf out.pdf  # Decrypt
```

## Common Tasks

### Extract Text from Scanned PDFs (OCR)
```python
import pytesseract
from pdf2image import convert_from_path

images = convert_from_path('scanned.pdf')
text = ""
for i, image in enumerate(images):
    text += f"Page {i+1}:\n"
    text += pytesseract.image_to_string(image)
    text += "\n\n"
```

### Add Watermark
```python
from pypdf import PdfReader, PdfWriter

watermark = PdfReader("watermark.pdf").pages[0]
reader = PdfReader("document.pdf")
writer = PdfWriter()

for page in reader.pages:
    page.merge_page(watermark)
    writer.add_page(page)

with open("watermarked.pdf", "wb") as output:
    writer.write(output)
```

### Password Protection
```python
from pypdf import PdfReader, PdfWriter

reader = PdfReader("input.pdf")
writer = PdfWriter()
for page in reader.pages:
    writer.add_page(page)
writer.encrypt("userpassword", "ownerpassword")
with open("encrypted.pdf", "wb") as output:
    writer.write(output)
```

## Quick Reference

| Task | Best Tool | Command/Code |
|------|-----------|--------------|
| Merge PDFs | pypdf | `writer.add_page(page)` |
| Split PDFs | pypdf | One page per file |
| Extract text | pdfplumber | `page.extract_text()` |
| Extract tables | pdfplumber | `page.extract_tables()` |
| Create PDFs | reportlab | Canvas or Platypus |
| Fill forms | scripts | `fill_fillable_fields.py` |
| OCR scanned PDFs | pytesseract | Convert to image first |