• Read info
• Rotate Page
• Merge PDFs
• Split PDFs
• Encrypt a PDF
• Decrypt a PDF
• Add watermark

reference: How to Work With a PDF in Python
reference: 给PDF添加水印

本文使用的PDF处理库为pypdf2

Read info

def extract_information(pdf_path):
    with open(pdf_path, 'rb') as f:
        pdf = PdfFileReader(f)
        information = pdf.getDocumentInfo()
        number_of_pages = pdf.getNumPages()
		# multiply 0.352 to convert inches to millimeters
        height = float(pdf.getPage(0).mediaBox.getHeight()) * 0.352
        width = float(pdf.getPage(0).mediaBox.getWidth()) * 0.352

    txt = f"""
    Information about {pdf_path}: 

    Author: {information.author}
    Creator: {information.creator}
    Producer: {information.producer}
    Subject: {information.subject}
    Title: {information.title}
    Number of pages: {number_of_pages}
    Height: {height:.2f}
    Width: {width:.2f}
    """

    print(txt)

Rotate Page

def rotate_pages(pdf_path):
    pdf_writer = PdfFileWriter()
    pdf_reader = PdfFileReader(pdf_path)
    # Rotate page 90 degrees to the right
    page_1 = pdf_reader.getPage(0).rotateClockwise(90)
    pdf_writer.addPage(page_1)
    # Rotate page 90 degrees to the left
    page_2 = pdf_reader.getPage(1).rotateCounterClockwise(90)
    pdf_writer.addPage(page_2)
    # Add a page in normal orientation
    pdf_writer.addPage(pdf_reader.getPage(2))

    with open('rotate_pages.pdf', 'wb') as fh:
        pdf_writer.write(fh)

Merge PDFs

def merge_pdfs(paths : list, output : str):
    pdf_writer = PdfFileWriter()

    for path in paths:
        pdf_reader = PdfFileReader(path)
        for page in range(pdf_reader.getNumPages()):
            # Add each page to the writer object
            pdf_writer.addPage(pdf_reader.getPage(page))

    # Write out the merged PDF
    with open(output, 'wb') as out:
        pdf_writer.write(out)

Split PDFs

def split(path, name_of_split):
    pdf = PdfFileReader(path)
    for page in range(pdf.getNumPages()):
        pdf_writer = PdfFileWriter()
        pdf_writer.addPage(pdf.getPage(page))

        output = f'{name_of_split}{page}.pdf'
        with open(output, 'wb') as output_pdf:
            pdf_writer.write(output_pdf)

Encrypt a PDF

def add_encryption(input_pdf, output_pdf, password):
    pdf_writer = PdfFileWriter()
    pdf_reader = PdfFileReader(input_pdf)

    for page in range(pdf_reader.getNumPages()):
        pdf_writer.addPage(pdf_reader.getPage(page))
	# or use pdf_writer.appendPagesFromReader(pdf_reader)
    pdf_writer.encrypt(user_pwd=password, owner_pwd=None, 
                       use_128bit=True)

    with open(output_pdf, 'wb') as fh:
        pdf_writer.write(fh)

Decrypt a PDF

def decrypt_pdf(input_pdf, output_pdf, password):
    pdf_writer = PdfFileWriter()
    pdf_reader = PdfFileReader(input_pdf)

    if pdf_reader.isEncrypted:
        try:
            pdf_reader.decrypt(password)
        except:
            print("Wrong password")
    else:
        print("File is not encrypted")

    for page in range(pdf_reader.getNumPages()):
        pdf_writer.addPage(pdf_reader.getPage(page))

    with open(output_pdf, 'wb') as fh:
        pdf_writer.write(fh)

Add watermark

使用word制作水印页面。
设计->水印->自定义水印，导出PDF作为watermark.pdf。

def create_watermark(input_pdf, output, watermark):
    watermark_obj = PdfFileReader(watermark)
    watermark_page = watermark_obj.getPage(0)

    pdf_reader = PdfFileReader(input_pdf)
    pdf_writer = PdfFileWriter()
    # multiply 0.352 to convert inches to millimeters
    print(f"watermask height: {0.352 * float(watermark_page.mediaBox.getHeight()):.2f}, \
            watermask width: {0.352 * float(watermark_page.mediaBox.getWidth()):.2f}")
    # Watermark all the pages
    for page in range(pdf_reader.getNumPages()):
        page = pdf_reader.getPage(page)
        print(f"page height: {0.352 * float(page.mediaBox.getHeight()):.2f}, \
                page width: {0.352 * float(page.mediaBox.getWidth()):.2f}")
        page.mergePage(watermark_page)
        pdf_writer.addPage(page)

    with open(output, 'wb') as out:
        pdf_writer.write(out)