315 lines
7.8 KiB
Markdown
315 lines
7.8 KiB
Markdown
---
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name: pdf
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description: 当用户想要对 PDF 文件进行任何操作时使用此技能。包括从 PDF 中读取或提取文本/表格、合并多个 PDF 为一个、拆分 PDF、旋转页面、添加水印、创建新 PDF、填写 PDF 表单、加密/解密 PDF、提取图像以及对扫描的 PDF 进行 OCR 使其可搜索。如果用户提到 .pdf 文件或要求生成 PDF，请使用此技能。
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license: Proprietary. LICENSE.txt has complete terms
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---
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# PDF Processing Guide
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## Overview
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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.
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## Quick Start
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```python
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from pypdf import PdfReader, PdfWriter
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# Read a PDF
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reader = PdfReader("document.pdf")
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print(f"Pages: {len(reader.pages)}")
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# Extract text
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text = ""
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for page in reader.pages:
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text += page.extract_text()
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```
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## Python Libraries
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### pypdf - Basic Operations
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#### Merge PDFs
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```python
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from pypdf import PdfWriter, PdfReader
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writer = PdfWriter()
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for pdf_file in ["doc1.pdf", "doc2.pdf", "doc3.pdf"]:
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reader = PdfReader(pdf_file)
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for page in reader.pages:
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writer.add_page(page)
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with open("merged.pdf", "wb") as output:
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writer.write(output)
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```
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#### Split PDF
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```python
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reader = PdfReader("input.pdf")
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for i, page in enumerate(reader.pages):
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writer = PdfWriter()
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writer.add_page(page)
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with open(f"page_{i+1}.pdf", "wb") as output:
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writer.write(output)
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```
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#### Extract Metadata
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```python
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reader = PdfReader("document.pdf")
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meta = reader.metadata
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print(f"Title: {meta.title}")
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print(f"Author: {meta.author}")
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print(f"Subject: {meta.subject}")
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print(f"Creator: {meta.creator}")
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```
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#### Rotate Pages
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```python
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reader = PdfReader("input.pdf")
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writer = PdfWriter()
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page = reader.pages[0]
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page.rotate(90) # Rotate 90 degrees clockwise
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writer.add_page(page)
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with open("rotated.pdf", "wb") as output:
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writer.write(output)
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```
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### pdfplumber - Text and Table Extraction
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#### Extract Text with Layout
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```python
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import pdfplumber
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with pdfplumber.open("document.pdf") as pdf:
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for page in pdf.pages:
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text = page.extract_text()
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print(text)
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```
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#### Extract Tables
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```python
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with pdfplumber.open("document.pdf") as pdf:
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for i, page in enumerate(pdf.pages):
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tables = page.extract_tables()
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for j, table in enumerate(tables):
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print(f"Table {j+1} on page {i+1}:")
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for row in table:
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print(row)
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```
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#### Advanced Table Extraction
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```python
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import pandas as pd
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with pdfplumber.open("document.pdf") as pdf:
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all_tables = []
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for page in pdf.pages:
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tables = page.extract_tables()
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for table in tables:
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if table: # Check if table is not empty
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df = pd.DataFrame(table[1:], columns=table[0])
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all_tables.append(df)
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# Combine all tables
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if all_tables:
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combined_df = pd.concat(all_tables, ignore_index=True)
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combined_df.to_excel("extracted_tables.xlsx", index=False)
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```
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### reportlab - Create PDFs
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#### Basic PDF Creation
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```python
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from reportlab.lib.pagesizes import letter
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from reportlab.pdfgen import canvas
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c = canvas.Canvas("hello.pdf", pagesize=letter)
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width, height = letter
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# Add text
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c.drawString(100, height - 100, "Hello World!")
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c.drawString(100, height - 120, "This is a PDF created with reportlab")
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# Add a line
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c.line(100, height - 140, 400, height - 140)
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# Save
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c.save()
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```
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#### Create PDF with Multiple Pages
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```python
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from reportlab.lib.pagesizes import letter
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from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, PageBreak
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from reportlab.lib.styles import getSampleStyleSheet
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doc = SimpleDocTemplate("report.pdf", pagesize=letter)
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styles = getSampleStyleSheet()
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story = []
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# Add content
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title = Paragraph("Report Title", styles['Title'])
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story.append(title)
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story.append(Spacer(1, 12))
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body = Paragraph("This is the body of the report. " * 20, styles['Normal'])
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story.append(body)
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story.append(PageBreak())
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# Page 2
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story.append(Paragraph("Page 2", styles['Heading1']))
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story.append(Paragraph("Content for page 2", styles['Normal']))
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# Build PDF
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doc.build(story)
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```
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#### Subscripts and Superscripts
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**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.
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Instead, use ReportLab's XML markup tags in Paragraph objects:
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```python
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from reportlab.platypus import Paragraph
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from reportlab.lib.styles import getSampleStyleSheet
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styles = getSampleStyleSheet()
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# Subscripts: use <sub> tag
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chemical = Paragraph("H<sub>2</sub>O", styles['Normal'])
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# Superscripts: use <super> tag
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squared = Paragraph("x<super>2</super> + y<super>2</super>", styles['Normal'])
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```
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For canvas-drawn text (not Paragraph objects), manually adjust font the size and position rather than using Unicode subscripts/superscripts.
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## Command-Line Tools
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### pdftotext (poppler-utils)
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```bash
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# Extract text
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pdftotext input.pdf output.txt
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# Extract text preserving layout
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pdftotext -layout input.pdf output.txt
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# Extract specific pages
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pdftotext -f 1 -l 5 input.pdf output.txt # Pages 1-5
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```
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### qpdf
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```bash
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# Merge PDFs
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qpdf --empty --pages file1.pdf file2.pdf -- merged.pdf
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# Split pages
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qpdf input.pdf --pages . 1-5 -- pages1-5.pdf
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qpdf input.pdf --pages . 6-10 -- pages6-10.pdf
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# Rotate pages
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qpdf input.pdf output.pdf --rotate=+90:1 # Rotate page 1 by 90 degrees
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# Remove password
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qpdf --password=mypassword --decrypt encrypted.pdf decrypted.pdf
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```
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### pdftk (if available)
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```bash
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# Merge
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pdftk file1.pdf file2.pdf cat output merged.pdf
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# Split
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pdftk input.pdf burst
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# Rotate
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pdftk input.pdf rotate 1east output rotated.pdf
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```
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## Common Tasks
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### Extract Text from Scanned PDFs
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```python
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# Requires: pip install pytesseract pdf2image
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import pytesseract
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from pdf2image import convert_from_path
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# Convert PDF to images
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images = convert_from_path('scanned.pdf')
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# OCR each page
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text = ""
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for i, image in enumerate(images):
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text += f"Page {i+1}:\n"
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text += pytesseract.image_to_string(image)
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text += "\n\n"
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print(text)
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```
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### Add Watermark
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```python
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from pypdf import PdfReader, PdfWriter
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# Create watermark (or load existing)
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watermark = PdfReader("watermark.pdf").pages[0]
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# Apply to all pages
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reader = PdfReader("document.pdf")
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writer = PdfWriter()
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for page in reader.pages:
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page.merge_page(watermark)
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writer.add_page(page)
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with open("watermarked.pdf", "wb") as output:
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writer.write(output)
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```
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### Extract Images
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```bash
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# Using pdfimages (poppler-utils)
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pdfimages -j input.pdf output_prefix
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# This extracts all images as output_prefix-000.jpg, output_prefix-001.jpg, etc.
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```
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### Password Protection
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```python
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from pypdf import PdfReader, PdfWriter
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reader = PdfReader("input.pdf")
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writer = PdfWriter()
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for page in reader.pages:
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writer.add_page(page)
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# Add password
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writer.encrypt("userpassword", "ownerpassword")
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with open("encrypted.pdf", "wb") as output:
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writer.write(output)
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```
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## Quick Reference
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| Task | Best Tool | Command/Code |
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|------|-----------|--------------|
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| Merge PDFs | pypdf | `writer.add_page(page)` |
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| Split PDFs | pypdf | One page per file |
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| Extract text | pdfplumber | `page.extract_text()` |
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| Extract tables | pdfplumber | `page.extract_tables()` |
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| Create PDFs | reportlab | Canvas or Platypus |
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| Command line merge | qpdf | `qpdf --empty --pages ...` |
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| OCR scanned PDFs | pytesseract | Convert to image first |
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| Fill PDF forms | pdf-lib or pypdf (see FORMS.md) | See FORMS.md |
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## Next Steps
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- For advanced pypdfium2 usage, see REFERENCE.md
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- For JavaScript libraries (pdf-lib), see REFERENCE.md
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- If you need to fill out a PDF form, follow the instructions in FORMS.md
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- For troubleshooting guides, see REFERENCE.md
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