sinaptik-ai PDF Processing
Quick Reference
| Task | Tool | Script |
|---|---|---|
| Extract text | pdfplumber | page.extract_text() |
| Extract tables | pdfplumber | python scripts/extract_tables.py input.pdf |
| Merge PDFs | pypdf | python scripts/merge.py output.pdf a.pdf b.pdf |
| Convert to images | poppler-utils | python scripts/convert_to_images.py input.pdf |
| Fill form fields | pypdf | python scripts/fill_form.py form.pdf --list |
| Create new PDF | reportlab | SimpleDocTemplate or Canvas |
| OCR scanned PDF | pytesseract + pdf2image | image_to_string() |
| CLI text extraction | poppler-utils | pdftotext |
| CLI merge/split | qpdf | qpdf --empty --pages |
For form filling workflow, see references/forms.md.
For advanced libraries (pypdfium2, pdf-lib), see references/advanced.md.
Reading & Extracting
Text extraction
import pdfplumber
with pdfplumber.open("document.pdf") as pdf:
for page in pdf.pages:
print(page.extract_text())
Table extraction → DataFrame
import pdfplumber, pandas as pd
with pdfplumber.open("document.pdf") as pdf:
tables = []
for page in pdf.pages:
for table in page.extract_tables():
if table:
df = pd.DataFrame(table[1:], columns=table[0])
tables.append(df)
if tables:
combined = pd.concat(tables, ignore_index=True)
combined.to_excel("tables.xlsx", index=False)
Metadata
from pypdf import PdfReader
reader = PdfReader("document.pdf")
meta = reader.metadata
print(f"Title: {meta.title}, Author: {meta.author}, Pages: {len(reader.pages)}")
Merging & Splitting
Merge multiple PDFs
from pypdf import PdfWriter, PdfReader
writer = PdfWriter()
for path in ["a.pdf", "b.pdf", "c.pdf"]:
for page in PdfReader(path).pages:
writer.add_page(page)
with open("merged.pdf", "wb") as f:
writer.write(f)
Split into individual pages
from pypdf import PdfReader, PdfWriter
for i, page in enumerate(PdfReader("input.pdf").pages):
w = PdfWriter()
w.add_page(page)
with open(f"page_{i+1}.pdf", "wb") as f:
w.write(f)
Extract page range
from pypdf import PdfReader, PdfWriter
reader = PdfReader("input.pdf")
writer = PdfWriter()
for page in reader.pages[2:7]: # pages 3-7 (0-indexed)
writer.add_page(page)
with open("excerpt.pdf", "wb") as f:
writer.write(f)
Rotating Pages
from pypdf import PdfReader, PdfWriter
reader = PdfReader("input.pdf")
writer = PdfWriter()
for page in reader.pages:
page.rotate(90) # 90, 180, 270
writer.add_page(page)
with open("rotated.pdf", "wb") as f:
writer.write(f)
Creating New PDFs
Simple document with reportlab
from reportlab.lib.pagesizes import letter
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle, PageBreak
from reportlab.lib.styles import getSampleStyleSheet
from reportlab.lib import colors
doc = SimpleDocTemplate("report.pdf", pagesize=letter)
styles = getSampleStyleSheet()
story = []
story.append(Paragraph("Report Title", styles['Title']))
story.append(Spacer(1, 24))
story.append(Paragraph("Body text goes here. " * 10, styles['Normal']))
# Table
data = [["Name", "Score"], ["Alice", "95"], ["Bob", "87"]]
t = Table(data, colWidths=[200, 100])
t.setStyle(TableStyle([
('BACKGROUND', (0, 0), (-1, 0), colors.HexColor('#333333')),
('TEXTCOLOR', (0, 0), (-1, 0), colors.white),
('GRID', (0, 0), (-1, -1), 0.5, colors.grey),
('FONTSIZE', (0, 0), (-1, -1), 10),
]))
story.append(t)
story.append(PageBreak())
story.append(Paragraph("Page 2 content", styles['Heading1']))
doc.build(story)
CRITICAL: Subscripts and superscripts in reportlab
Never use Unicode subscript/superscript characters (₀₁₂₃₄₅₆₇₈₉, ⁰¹²³⁴⁵⁶⁷⁸⁹) — built-in fonts render them as black boxes.
Use XML markup in Paragraph objects instead:
Paragraph("H<sub>2</sub>O and x<super>2</super>", styles['Normal'])
Watermarks & Security
Add watermark
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 f:
writer.write(f)
Password protection
from pypdf import PdfReader, PdfWriter
reader = PdfReader("input.pdf")
writer = PdfWriter()
for page in reader.pages:
writer.add_page(page)
writer.encrypt("userpass", "ownerpass")
with open("encrypted.pdf", "wb") as f:
writer.write(f)
OCR for Scanned PDFs
import pytesseract
from pdf2image import convert_from_path
images = convert_from_path("scanned.pdf")
text = "\n\n".join(
f"--- Page {i+1} ---\n{pytesseract.image_to_string(img)}"
for i, img in enumerate(images)
)
Requires: pip install pytesseract pdf2image and system packages tesseract-ocr, poppler-utils.
CLI Quick Reference
# Text extraction (poppler-utils)
pdftotext input.pdf output.txt
pdftotext -layout input.pdf output.txt # preserve layout
pdftotext -f 1 -l 5 input.pdf output.txt # pages 1-5
# Merge (qpdf)
qpdf --empty --pages a.pdf b.pdf -- merged.pdf
# Split page range
qpdf input.pdf --pages . 1-5 -- first5.pdf
# Rotate page 1 by 90°
qpdf input.pdf output.pdf --rotate=+90:1
# Decrypt
qpdf --password=PASS --decrypt encrypted.pdf decrypted.pdf
# Extract images (poppler-utils)
pdfimages -j input.pdf prefix # outputs prefix-000.jpg, etc.