processing-pdfs

name	processing-pdfs
description	Extracts text and tables from PDF files, takes screenshots of pages, merges/splits documents, creates new PDFs, and fills forms. Use when working with PDF files, .pdf extensions, document extraction, form filling, PDF manipulation, or rendering PDF pages as images.

PDF Processing

Contents

• Text extraction (priority order)
• Table extraction (pdfplumber)
• Screenshot/render pages to images
• Merge, split, rotate (pypdf)
• Create PDFs (reportlab)
• Command-line tools (qpdf, pdftotext)
• OCR for scanned PDFs

Form filling: See forms.md Advanced features: See reference.md

Text Extraction - Priority Order

ALWAYS try methods in this order:

1. Built-in Read Tool (FIRST CHOICE)

Read("document.pdf")

The Read tool natively supports PDF text extraction. Try this first - it's the simplest and often sufficient.

2. pypdf (FALLBACK - Best accuracy)

Use if Read tool fails or returns poor results:

from pypdf import PdfReader

reader = PdfReader("document.pdf")
text = ""
for page in reader.pages:
    text += page.extract_text()

Benchmark: 72-97% word accuracy on academic PDFs.

3. pdfplumber (For tables or layout-sensitive text)

Use when you need tables or layout preservation:

import pdfplumber

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

Note: Lower accuracy for plain text (35-61%), but excellent for tables.

4. pdftotext CLI (Quick extraction)

pdftotext -layout input.pdf output.txt

Decision Flow

PDF Text Extraction:
├── Try Read("file.pdf") first
│   ├── Success? → Done
│   └── Failed/Poor quality? → Continue
├── Try pypdf (best accuracy)
│   ├── Success? → Done
│   └── Failed? → Continue
├── Has tables? → Use pdfplumber
└── Scanned/Image PDF? → Use OCR (pytesseract)

Screenshot PDF Pages

Take screenshots of PDF pages to render them as images. Useful for visual inspection, image-based analysis, or when you need to see the exact layout.

Constraints:

• File must have .pdf extension
• Maximum file size: 100MB
• Page numbers must be >= 1

Single Page Screenshot

from pdf2image import convert_from_path
from PIL import Image

def screenshot_page(pdf_path, page_number=1, output_path=None, dpi=150, max_dim=1500):
    """Take a screenshot of a specific page from a PDF."""
    images = convert_from_path(
        pdf_path, 
        dpi=dpi, 
        first_page=page_number, 
        last_page=page_number
    )
    
    image = images[0]
    
    # Scale if needed
    width, height = image.size
    if width > max_dim or height > max_dim:
        scale_factor = min(max_dim / width, max_dim / height)
        image = image.resize(
            (int(width * scale_factor), int(height * scale_factor)), 
            Image.Resampling.LANCZOS
        )
    
    if output_path is None:
        output_path = f"page_{page_number}.png"
    
    image.save(output_path, "PNG")
    return output_path

Multiple Pages Screenshot

from pdf2image import convert_from_path

# Screenshot all pages
images = convert_from_path("document.pdf", dpi=150)
for i, image in enumerate(images):
    image.save(f"page_{i+1}.png", "PNG")

# Screenshot specific pages (1, 3, 5)
for page_num in [1, 3, 5]:
    images = convert_from_path(
        "document.pdf", 
        dpi=150, 
        first_page=page_num, 
        last_page=page_num
    )
    images[0].save(f"page_{page_num}.png", "PNG")

Command Line Screenshot

# Using the screenshot_pdf_page.py script
python screenshot_pdf_page.py document.pdf 1              # Screenshot page 1
python screenshot_pdf_page.py document.pdf --all          # Screenshot all pages
python screenshot_pdf_page.py document.pdf 3 output.png   # Screenshot page 3 to output.png

# Using pdftoppm (poppler-utils) - fastest method
pdftoppm -png -r 150 document.pdf output_prefix

# Screenshot specific page (page 3)
pdftoppm -png -r 150 -f 3 -l 3 document.pdf page_3

# High resolution screenshot
pdftoppm -png -r 300 document.pdf high_res

Screenshot Decision Flow

Need PDF Screenshot:
├── Single page? → Use pdf2image with first_page/last_page
├── All pages? → Use convert_from_path() or --all flag
├── High quality needed? → Use dpi=300 or higher
└── Need to scale? → Use PIL Image.resize() with Resampling.LANCZOS

Python Libraries

pypdf - Basic Operations

Merge PDFs

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

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

reader = PdfReader("document.pdf")
meta = reader.metadata
print(f"Title: {meta.title}")
print(f"Author: {meta.author}")
print(f"Subject: {meta.subject}")
print(f"Creator: {meta.creator}")

Rotate Pages

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 - Table Extraction

Extract Tables

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

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:  # Check if table is not empty
                df = pd.DataFrame(table[1:], columns=table[0])
                all_tables.append(df)

# Combine all tables
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

from reportlab.lib.pagesizes import letter
from reportlab.pdfgen import canvas

c = canvas.Canvas("hello.pdf", pagesize=letter)
width, height = letter

# Add text
c.drawString(100, height - 100, "Hello World!")
c.drawString(100, height - 120, "This is a PDF created with reportlab")

# Add a line
c.line(100, height - 140, 400, height - 140)

# Save
c.save()

Create PDF with Multiple Pages

from reportlab.lib.pagesizes import letter
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, PageBreak
from reportlab.lib.styles import getSampleStyleSheet

doc = SimpleDocTemplate("report.pdf", pagesize=letter)
styles = getSampleStyleSheet()
story = []

# Add content
title = Paragraph("Report Title", styles['Title'])
story.append(title)
story.append(Spacer(1, 12))

body = Paragraph("This is the body of the report. " * 20, styles['Normal'])
story.append(body)
story.append(PageBreak())

# Page 2
story.append(Paragraph("Page 2", styles['Heading1']))
story.append(Paragraph("Content for page 2", styles['Normal']))

# Build PDF
doc.build(story)

Command-Line Tools

pdftotext (poppler-utils)

# Extract text
pdftotext input.pdf output.txt

# Extract text preserving layout
pdftotext -layout input.pdf output.txt

# Extract specific pages
pdftotext -f 1 -l 5 input.pdf output.txt  # Pages 1-5

qpdf

# Merge PDFs
qpdf --empty --pages file1.pdf file2.pdf -- merged.pdf

# Split pages
qpdf input.pdf --pages . 1-5 -- pages1-5.pdf
qpdf input.pdf --pages . 6-10 -- pages6-10.pdf

# Rotate pages
qpdf input.pdf output.pdf --rotate=+90:1  # Rotate page 1 by 90 degrees

# Remove password
qpdf --password=mypassword --decrypt encrypted.pdf decrypted.pdf

pdftk (if available)

# Merge
pdftk file1.pdf file2.pdf cat output merged.pdf

# Split
pdftk input.pdf burst

# Rotate
pdftk input.pdf rotate 1east output rotated.pdf

Common Tasks

Extract Text from Scanned PDFs

# Requires: pip install pytesseract pdf2image
import pytesseract
from pdf2image import convert_from_path

# Convert PDF to images
images = convert_from_path('scanned.pdf')

# OCR each page
text = ""
for i, image in enumerate(images):
    text += f"Page {i+1}:\n"
    text += pytesseract.image_to_string(image)
    text += "\n\n"

print(text)

Add Watermark

from pypdf import PdfReader, PdfWriter

# Create watermark (or load existing)
watermark = PdfReader("watermark.pdf").pages[0]

# Apply to all pages
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)

Extract Images

# Using pdfimages (poppler-utils)
pdfimages -j input.pdf output_prefix

# This extracts all images as output_prefix-000.jpg, output_prefix-001.jpg, etc.

Password Protection

from pypdf import PdfReader, PdfWriter

reader = PdfReader("input.pdf")
writer = PdfWriter()

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

# Add password
writer.encrypt("userpassword", "ownerpassword")

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

Quick Reference

Task	Best Tool	Command/Code
Extract text	1. Read tool	Read("file.pdf")
Extract text (fallback)	2. pypdf	page.extract_text()
Extract tables	pdfplumber	page.extract_tables()
Screenshot page	pdf2image	convert_from_path(pdf, first_page=N, last_page=N)
Screenshot (CLI)	pdftoppm	pdftoppm -png -r 150 -f 1 -l 1 input.pdf output
Merge PDFs	pypdf	writer.add_page(page)
Split PDFs	pypdf	One page per file
Create PDFs	reportlab	Canvas or Platypus
Command line extract	pdftotext	pdftotext -layout input.pdf
Command line merge	qpdf	qpdf --empty --pages ...
OCR scanned PDFs	pytesseract	Convert to image first
Fill PDF forms	pypdf or pdf-lib	See forms.md

Next Steps

• For advanced pypdfium2 usage, see reference.md
• For JavaScript libraries (pdf-lib), see reference.md
• If you need to fill out a PDF form, follow the instructions in forms.md
• For troubleshooting guides, see reference.md