PDF Processing

Instructions

Step 1: Identify the Operation

Determine what the user needs: read/extract text, merge, split, rotate, create, fill forms, OCR, watermark, encrypt/decrypt, or extract images. If the task involves filling a PDF form, read references/forms.md and follow its instructions instead of continuing here.

Step 2: Choose the Right Tool

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

Command line merge qpdf qpdf --empty --pages ...

OCR scanned PDFs pytesseract Convert to image first

Fill PDF forms pypdf or annotations (see references/forms.md ) See references/forms.md

Step 3: Execute

Use the code patterns below, organized by tool/library.

Quick Start

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()

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 - Text and Table Extraction

Extract Text with Layout:

import pdfplumber

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

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)

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:

from reportlab.platypus import Paragraph from reportlab.lib.styles import getSampleStyleSheet

styles = getSampleStyleSheet()

Subscripts: use <sub> tag

chemical = Paragraph("H₂O", styles['Normal'])

Superscripts: use <super> tag

squared = Paragraph("x<super>2</super> + y<super>2</super>", styles['Normal'])

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 (OCR):

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)

Step 4: Verify Output

Open the output PDF and confirm the operation succeeded. For form fills, convert the filled PDF to images and visually verify text placement:

from pdf2image import convert_from_path images = convert_from_path("output.pdf") for i, img in enumerate(images): img.save(f"verify_page_{i+1}.png")

Examples

Extract text from a multi-page PDF

User: "Extract all the text from report.pdf"

Use pdfplumber to extract text page by page, then combine into a single output.

Merge three invoices into one file

User: "Combine invoice_jan.pdf, invoice_feb.pdf, and invoice_mar.pdf into one PDF"

Use pypdf's PdfWriter to iterate through all pages of each file and write to a merged output.

Fill out a government form

User: "Fill out form W-9.pdf with my company info"

Follow references/forms.md : check for fillable fields, extract field info, create field values JSON, and fill using the appropriate script.

Troubleshooting

Encrypted PDF blocks all operations

Solution: Decrypt first with qpdf --password=SECRET --decrypt encrypted.pdf decrypted.pdf , or in Python: reader = PdfReader("file.pdf"); reader.decrypt("password") . If you don't have the password, the file cannot be processed.

Text extraction returns empty strings or garbage

Solution: The PDF is likely scanned/image-based. Fall back to OCR: convert pages to images with pdf2image , then run pytesseract.image_to_string() on each page image.

Missing Python dependency (pypdf, pdfplumber, reportlab, etc.)

Solution: Install the required package with pip: pip install pypdf pdfplumber reportlab pdf2image pytesseract . For command-line tools like pdftotext or qpdf , install via the system package manager (e.g., brew install poppler qpdf on macOS).

Notes

• Tool selection: pypdf for structural operations (merge, split, rotate, encrypt), pdfplumber for text/table extraction, reportlab for creating new PDFs, pytesseract+pdf2image for OCR on scanned documents.

• Advanced features: See references/reference.md for pypdfium2, JavaScript libraries (pdf-lib, pdfjs-dist), advanced CLI usage, and performance optimization.

• Form filling: See references/forms.md for the complete form-filling workflow including fillable fields, non-fillable annotation-based filling, and validation scripts.