pdf

# 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 ```python 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 ```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 - Text and Table Extraction #### Extract Text with Layout ```python import pdfplumber with pdfplumber.open("document.pdf") as pdf: for page in pdf.pages: text = page.extract_text() print(text) ``` #### 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) ``` #### Korean Font Support (한글 폰트 지원) **CRITICAL**: reportlab은 기본적으로 한글을 지원하지 않습니다. 한글을 사용하려면 시스템의 한글 폰트를 찾아서 등록해야 합니다. ```python 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:** ```python 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: `ParagraphStyle`에서 `fontName='KoreanFont'` 지정 ## 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 | |------|-----------|--------------| | 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