PDF Processing Guide

Overview

This guide covers essential PDF processing operations using Python libraries and command-line tools. For advanced features, JavaScript libraries, and detailed examples, see REFERENCE.md. If you need to fill out a PDF form, read FORMS.md and follow its instructions.

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()

Creating Professional PDFs

Use the built-in md2pdf.py script to create publication-quality PDF documents with cover pages, table of contents, themed styling, and full CJK/Latin support. Write content as Markdown, then render it into a professionally typeset PDF.

When to Use

• User wants to create a PDF report, article, white paper, or document
• User wants professional typesetting with cover page, TOC, headers/footers
• Document contains CJK characters (Chinese/Japanese/Korean) mixed with Latin text
• User wants a specific design theme or branded document

Workflow

1. Understand what document the user wants to create
2. Write the content as a Markdown file
3. Ask the user about design options (see below)
4. Run the converter to generate the PDF

pip install reportlab --break-system-packages

python pdf/scripts/md2pdf.py \
  --input report.md \
  --output report.pdf \
  --title "My Report" \
  --author "Author Name" \
  --theme warm-academic

All parameters except --input are optional — sensible defaults are applied.

Pre-Conversion Options (MANDATORY)

IMPORTANT: You MUST use the AskUserQuestion tool to ask these questions BEFORE running the conversion. Ask all options in a SINGLE AskUserQuestion call.

开始生成 PDF！先帮你确认几个选项 👇

━━━ 📐 设计风格 ━━━
 a) 暖学术    — 陶土色调，温润典雅，适合人文/社科报告
 b) 经典论文  — 棕色调，灵感源自 LaTeX classicthesis，适合学术论文
 c) Tufte     — 极简留白，深红点缀，适合数据叙事/技术写作
 d) 期刊蓝    — 藏蓝严谨，灵感源自 IEEE，适合正式发表风格
 e) 精装书    — 咖啡色调，书卷气，适合长篇专著/技术书
 f) 中国红    — 朱红配暖纸，适合中文正式报告/白皮书
 g) 水墨      — 纯灰黑，素雅克制，适合文学/设计类内容
 h) GitHub    — 蓝白极简，程序员熟悉的风格
 i) Nord 冰霜 — 蓝灰北欧风，清爽现代
 j) 海洋      — 青绿色调，清新自然

━━━ 🖼 扉页图片（封面之后的全页插图） ━━━
 1) 跳过
 2) 我提供本地图片路径
 3) AI 根据内容自动生成一张

━━━ 💧 水印 ━━━
 1) 不加
 2) 自定义文字（如 "DRAFT"、"内部资料"）

━━━ 📇 封底物料（名片/二维码/品牌） ━━━
 1) 跳过
 2) 我提供图片
 3) 纯文字信息

示例回复："a, 扉页跳过, 水印:仅供学习参考, 封底图片:/path/qr.png"
直接说人话就行，不用记编号 😄

Theme Name Mapping

Choice	--theme value	Inspiration
a) 暖学术	warm-academic	Lovstudio design system
b) 经典论文	classic-thesis	LaTeX classicthesis
c) Tufte	tufte	Edward Tufte's books
d) 期刊蓝	ieee-journal	IEEE journal format
e) 精装书	elegant-book	LaTeX ElegantBook
f) 中国红	chinese-red	Chinese formal documents
g) 水墨	ink-wash	水墨画 / ink wash painting
h) GitHub	github-light	GitHub Markdown style
i) Nord	nord-frost	Nord color scheme
j) 海洋	ocean-breeze	—

CLI Argument Mapping

User Choice	CLI arg
Design style a-j	--theme <value>
Frontispiece local	--frontispiece <path>
Frontispiece AI	Generate image first, then --frontispiece /tmp/frontispiece.png
Watermark text	--watermark "文字"
Back cover image	--banner <path>
Back cover text	--disclaimer "声明" and/or --copyright "© 信息"

Full Configuration Reference

Argument	Default	Description
--input	(required)	Path to markdown file
--output	output.pdf	Output PDF path
--title	From first H1	Document title for cover page
--subtitle	""	Subtitle text
--author	""	Author name
--date	Today	Date string
--version	""	Version string for cover
--watermark	""	Watermark text (empty = none)
--theme	warm-academic	Color theme name
--theme-file	""	Custom theme JSON file path
--cover	true	Generate cover page
--toc	true	Generate table of contents
--page-size	A4	Page size (A4 or Letter)
--frontispiece	""	Full-page image after cover
--banner	""	Back cover banner image
--header-title	""	Report title in page header
--footer-left	author	Brand/author in footer
--stats-line	""	Stats on cover
--stats-line2	""	Second stats line
--edition-line	""	Edition line at cover bottom
--disclaimer	""	Back cover disclaimer
--copyright	""	Back cover copyright
--code-max-lines	30	Max lines per code block

CJK Rendering Notes

• Always uses _font_wrap() for CJK/Latin mixed text — prevents □ rendering
• wordWrap='CJK' enables breaks at CJK character boundaries (no "Claude\nCode" splits)
• Canvas text (cover, headers, footers) uses _draw_mixed() for CJK characters
• Fonts: Palatino + Songti SC (macOS), Times + SimSun (Windows), Liberation + Noto CJK (Linux)

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 - 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 (₀₁₂₃₄₅₆₇₈₉, ⁰¹²³⁴⁵⁶⁷⁸⁹) in ReportLab PDFs. The built-in fonts do not include these glyphs, causing them to render as solid black boxes.

Instead, use ReportLab's XML markup tags in Paragraph objects:

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

styles = getSampleStyleSheet()

# Subscripts: use <sub> tag
chemical = Paragraph("H<sub>2</sub>O", styles['Normal'])

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

For canvas-drawn text (not Paragraph objects), manually adjust font the size and position rather than using Unicode subscripts/superscripts.

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
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	pdf-lib or pypdf (see FORMS.md)	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