Python Script to Add Watermark to PDF Document Using PyPDF2 Library in Command Line

Welcome folks today in this blog post we will be adding watermark to pdf document using pypdf2 library in python. All the full source code of the application is shown below.

Get Started

In order to get started you need to install the below library using the pip command as shown below

pip install pypdf2

After installing this make an app.py file and copy paste the following code

app.py

import PyPDF2

pdf_file = "sample.pdf"

watermark = "watermark.pdf"

merged_file = "merged.pdf"

import PyPDF2

pdf_file = "sample.pdf"

watermark = "watermark.pdf"

merged_file = "merged.pdf"

First of all we are declaring all the files which are needed for this application. So you need to load the watermark.pdf file which will look like this as shown below

input_file = open(pdf_file,'rb')
input_pdf = PyPDF2.PdfFileReader(input_file)

watermark_file = open(watermark,'rb')
watermark_pdf = PyPDF2.PdfFileReader(watermark_file)

input_file = open(pdf_file,'rb')

input_pdf = PyPDF2.PdfFileReader(input_file)

watermark_file = open(watermark,'rb')

watermark_pdf = PyPDF2.PdfFileReader(watermark_file)

Now we are opening both the input pdf file and the watermark pdf file using the open method and then we are reading the pdf files using the PdfFileReader() method.

pdf_page = input_pdf.getPage(0)

watermark_page = watermark_pdf.getPage(0)

pdf_page.mergePage(watermark_page)

pdf_page = input_pdf.getPage(0)

watermark_page = watermark_pdf.getPage(0)

pdf_page.mergePage(watermark_page)

Now we are taking the first page of each of the pdf document and then we are simply merging it just to give the impression that the watermark is added to the input pdf document. We are getting the first page of the pdf document using the getPage() method. And then we are using the mergePage() method to merge the pages inside the pdf document.

output = PyPDF2.PdfFileWriter()

output.addPage(pdf_page)

merged_file = open(merged_file,'wb')
output.write(merged_file)

merged_file.close()
watermark_file.close()
input_file.close()

output = PyPDF2.PdfFileWriter()

output.addPage(pdf_page)

merged_file = open(merged_file,'wb')

output.write(merged_file)

merged_file.close()

watermark_file.close()

input_file.close()

And now we are using the PdfFileWriter() method to write the file and then we are adding the page using the addPage()method. And then we are opening the resultant pdf file in write binary mode. And simply saving the file as merged.pdf in the root directory. And lastly we are closing the file connections. Now if you open the resultant pdf file the result will look like this as shown below