Watermark Removal on PDF with PyPDF2

Question

# This Section imports the necessary classes from the PyPDF2 library

from PyPDF2 import PdfFileReader, PdfFileWriter
from PyPDF2.generic import ContentStream, NameObject, TextStringObject
from PyPDF2.utils import b_

# The watermark says SAMPLE on it so I've tried different
# capitalization cases
wm_text = "Sample"
replace_with = ""
# I'm hoping to just replace the SAMPLE watermark with nothing
# so a space could suffice

# Load PDF into pyPDF
reader = PdfFileReader("input.pdf")
writer = PdfFileWriter()

for page in reader.pages:
    # Get the current page's contents
    content_object = page["/Contents"].getObject()
    content = ContentStream(content_object, reader)

    # Loop over all pdf elements
    for operands, operator in content.operations:

        # Was told to adapt this part dependent on my PDF file
        if operator == b_("TJ"):
            text = operands[0][0]
            if isinstance(text, TextStringObject) and text.startswith(
                wm_text
            ):
                operands[0] = TextStringObject(replace_with)

    # Set the modified content as content object on the page
    page.__setitem__(NameObject("/Contents"), content)

    # Add the page to the output
    writer.addPage(page)

# Write the stream
with open("output.pdf", "wb") as fh:
    writer.write(fh)

Answer 1

Using the code from the question here is a function that works in Python 3.

def remove_watermark(wm_text, inputFile, outputFile):
    from PyPDF4 import PdfFileReader, PdfFileWriter
    from PyPDF4.pdf import ContentStream
    from PyPDF4.generic import TextStringObject, NameObject
    from PyPDF4.utils import b_
    
    with open(inputFile, "rb") as f:
        source = PdfFileReader(f, "rb")
        output = PdfFileWriter()

        for page in range(source.getNumPages()):
            page = source.getPage(page)
            content_object = page["/Contents"].getObject()
            content = ContentStream(content_object, source)

            for operands, operator in content.operations:
                if operator == b_("Tj"):
                    text = operands[0]

                    if isinstance(text, str) and text.startswith(wm_text):
                        operands[0] = TextStringObject('')

            page.__setitem__(NameObject('/Contents'), content)
            output.addPage(page)

        with open(outputFile, "wb") as outputStream:
            output.write(outputStream)
            
wm_text = 'wm_text'
inputFile = r'input.pdf'
outputFile = r"output.pdf"
remove_watermark(wm_text, inputFile, outputFile)