Removing text from every page of a PDF

[j-t-1]

I am trying to remove two lines of text at the bottom of every page of a PDF.

from pypdf import PdfReader, PdfWriter

with open("example.pdf" "rb") as f0:
    reader = PdfReader(f0)

    for page in reader.pages:
        page.cropbox.lower_left = (0, 25)
        page.cropbox.lower_right = (595.276, 25)

    writer = PdfWriter(clone_from=reader)

    with open("out.pdf", "wb") as f1:
        writer.write(f1)

1. The above code is not working; is there an obvious fault or a better way?
2. Can the text be removed directly (something like deflate the PDF, then view
   it to see which object contains the text, then deleting the references)?

[stefan6419846]

The above code is not working; is there an obvious fault or a better way?

What do you mean by "not working"? Please note that just moving the box does not guarantee that the text will disappear, but maybe just hide it.

Can the text be removed directly (something like deflate the PDF, then view it to see which object contains the text, then deleting the references)?

This highly depends on the PDF itself, although it generally should be doable if the PDF file has a valid text layer. You probably want to have a look at page.get_contents and page.replace_contents for this.

[j-t-1]

Apologies for the ridiculously vague "not working"; I was expecting 25/72 inch to be clipped (not visible) from the bottom of each page.

This variation tries (but fails) to remove an inch from the bottom of the page:

from pypdf import PdfReader, PdfWriter

with open("input.pdf", "rb") as f0:
    reader = PdfReader(f0)

    for page in reader.pages:
        page.cropbox.lower_left = (0, 72)
        page.cropbox.upper_right = (595.276, 842)

    writer = PdfWriter(clone_from=reader)

    with open("out.pdf", "wb") as f1:
        writer.write(f1)

When using page.get_contents, is there a technique to find the resource containing the text wanted for removal?

[pubpub-zz]

I'm not sure this is due to size. Can you please provide the pdf for analysis

[j-t-1]

At the moment no. I will test with other large files and develop a hypothesis.

[j-t-1]

This gives the same error as writer = PdfWriter(clone_from="input.pdf"):

reader = PdfReader("input.pdf")
writer = PdfWriter()

# Does not work, but does if 4 is reduced to 3
for page in reader.pages[:4]:
    writer.add_page(page)`

@pubpub-zz I tried different PDFs with more pages, and they worked.

[stefan6419846]

Then this tends to be related to the corresponding page and requires further analysis on the actual file.

[j-t-1]

Finally got this working.

setrecursionlimit(10000)

writer = PdfWriter(clone_from='input.pdf')

for page in writer.pages:
    contents = page._get_contents_as_bytes()
    contents = contents[:contents.find(b'/Artifact BMC\n') - 1]
    stream = StreamObject()
    stream.set_data(contents)
    page.replace_contents(stream)

with open("output.pdf", "wb") as f:
    writer.write(f)

Thanks @pubpub-zz and @stefan6419846.