pdf（PDF 文档处理）

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()

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)

Korean Font Support (한글 폰트 지원)

CRITICAL: reportlab은 기본적으로 한글을 지원하지 않습니다. 한글을 사용하려면 시스템의 한글 폰트를 찾아서 등록해야 합니다.

from reportlab.lib.pagesizes import letter
from reportlab.pdfgen import canvas
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
import platform
import os

def get_korean_font_path():
    """시스템의 한글 폰트 경로를 찾습니다."""
    system = platform.system()

    if system == 'Darwin':  # macOS
        fonts = [
            '/System/Library/Fonts/Supplemental/AppleGothic.ttf',
            '/System/Library/Fonts/Supplemental/AppleMyungjo.ttf',
            '/Library/Fonts/NanumGothic.ttf'
        ]
    elif system == 'Windows':
        fonts = [
            'C:\\Windows\\Fonts\\malgun.ttf',  # 맑은 고딕
            'C:\\Windows\\Fonts\\gulim.ttc',   # 굴림
            'C:\\Windows\\Fonts\\batang.ttc'   # 바탕
        ]
    else:  # Linux
        fonts = [
            '/usr/share/fonts/truetype/nanum/NanumGothic.ttf',
            '/usr/share/fonts/truetype/nanum/NanumMyeongjo.ttf',
            '/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc'
        ]

    # 존재하는 첫 번째 폰트 반환
    for font_path in fonts:
        if os.path.exists(font_path):
            return font_path

    raise FileNotFoundError("한글 폰트를 찾을 수 없습니다. 시스템에 한글 폰트를 설치해주세요.")

# 한글 폰트 등록
korean_font_path = get_korean_font_path()
pdfmetrics.registerFont(TTFont('KoreanFont', korean_font_path))

# PDF 생성
c = canvas.Canvas("korean.pdf", pagesize=letter)
width, height = letter

# 한글 폰트 설정
c.setFont('KoreanFont', 12)

# 한글 텍스트 추가
c.drawString(100, height - 100, "안녕하세요! 한글 PDF 생성 테스트입니다.")
c.drawString(100, height - 120, "시스템의 한글 폰트를 자동으로 찾아서 사용합니다.")

c.save()

Platypus (고급 레이아웃)에서 한글 사용:

from reportlab.lib.pagesizes import letter
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
import platform
import os

def get_korean_font_path():
    """시스템의 한글 폰트 경로를 찾습니다."""
    system = platform.system()

    if system == 'Darwin':  # macOS
        fonts = [
            '/System/Library/Fonts/Supplemental/AppleGothic.ttf',
            '/System/Library/Fonts/Supplemental/AppleMyungjo.ttf',
            '/Library/Fonts/NanumGothic.ttf'
        ]
    elif system == 'Windows':
        fonts = [
            'C:\\Windows\\Fonts\\malgun.ttf',  # 맑은 고딕
            'C:\\Windows\\Fonts\\gulim.ttc',   # 굴림
            'C:\\Windows\\Fonts\\batang.ttc'   # 바탕
        ]
    else:  # Linux
        fonts = [
            '/usr/share/fonts/truetype/nanum/NanumGothic.ttf',
            '/usr/share/fonts/truetype/nanum/NanumMyeongjo.ttf',
            '/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc'
        ]

    for font_path in fonts:
        if os.path.exists(font_path):
            return font_path

    raise FileNotFoundError("한글 폰트를 찾을 수 없습니다.")

# 한글 폰트 등록
korean_font_path = get_korean_font_path()
pdfmetrics.registerFont(TTFont('KoreanFont', korean_font_path))

# 한글용 스타일 생성
styles = getSampleStyleSheet()
korean_style = ParagraphStyle(
    'Korean',
    parent=styles['Normal'],
    fontName='KoreanFont',
    fontSize=12,
    leading=18
)

korean_title = ParagraphStyle(
    'KoreanTitle',
    parent=styles['Title'],
    fontName='KoreanFont',
    fontSize=24,
    leading=30
)

# PDF 생성
doc = SimpleDocTemplate("korean_report.pdf", pagesize=letter)
story = []

# 한글 콘텐츠 추가
title = Paragraph("한글 리포트 제목", korean_title)
story.append(title)
story.append(Spacer(1, 12))

body = Paragraph("이것은 한글로 작성된 본문입니다. 시스템의 한글 폰트를 자동으로 찾아서 사용합니다.", korean_style)
story.append(body)

doc.build(story)

IMPORTANT:

• 한글 텍스트가 포함된 PDF를 생성할 때는 반드시 위의 get_korean_font_path() 함수를 사용하여 한글 폰트를 등록해야 합니다.
• Canvas 사용 시: c.setFont('KoreanFont', font_size)
• Platypus 사용 시: ParagraphStyle에서 fontName='KoreanFont' 지정

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

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