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)
code
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:
python
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:
python
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)
bash
pdftotext -layout input.pdf output.txt
Decision Flow
code
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
.pdfextension - •Maximum file size: 100MB
- •Page numbers must be >= 1
Single Page Screenshot
python
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
python
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
bash
# 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
code
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
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}")
print(f"Subject: {meta.subject}")
print(f"Creator: {meta.creator}")
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 - Table Extraction
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: # 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
python
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
python
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)
bash
# 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
bash
# 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)
bash
# 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
python
# 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
python
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
bash
# 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
python
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