Insert Page in a PDF - Page Numbering not correct?

[Rapid1898-code]

Hello - i try to add a front-page in pdf using the following code:

import os
import sys
import pymupdf

path = os.path.abspath(os.path.dirname(sys.argv[0])) 
fnInp = os.path.join(path, "type01.pdf")
fnDocTitle = os.path.join(path, "cover.pdf")
fnOut = os.path.join(path, "out.pdf")
with pymupdf.open(fnInp) as doc:
  docTitle = pymupdf.open(fnDocTitle)
  doc.insert_pdf(docTitle, to_page = 1, start_at = 0)    
  doc.save(fnOut)

Find attached the 2 input pdf:
cover.pdf
type01.pdf

And the output after the program run:
out.pdf

But the numbering of the pages in the final pdf-file out.pdf seems to be not correct.
When i want to print eg. the 2nd page of the document - it prints the 3rd page - see the print-dialog in Acrobat for example:

How can i add the cover and keep a correct page numbering?

[JorjMcKie]

Everything works as it should: The cover page is the first page of the output.

Not sure what is confusing you:

1. The page numbers shown bottom right of the old pages have not been changed of course! They are standard PDF text which does not change / cannot be changed by a page insertion.
2. The old PDF also has a definition for an "OpenAction" which is to show the page at xref 1. This is the xref of the old first page. Inserting a new first page of course does not change this: The page with xref 1 is still shown immediately after open.
3. But you can page backwards to see the inserted cover page.
4. When printing the PDF from a PDF viewer, the resulting behavior depends on the PDF viewer somewhat. Adobe for instance shows this (contradictory) window:

5. Using low-level functions, we can also remove that OpenAction ...

[Rapid1898-code]

I still try to add a cover-page before the initial pdf using the following code:

import os
import sys
import pymupdf
path = os.path.abspath(os.path.dirname(sys.argv[0])) 
fnCover = os.path.join(path, "cover.pdf")
fnInp = os.path.join(path, "inp.pdf")
fnOut = os.path.join(path, "out.pdf")
with pymupdf.open(fnInp) as doc:
  docTitle = pymupdf.open(fnCover)
  doc.insert_pdf(fnCover, to_page = 1, start_at = 0)    
  doc.save(fnOut)

But i get this error now:

(pdf) C:\DEV\Fiverr2025\ORDER\josemariamachad\TEST>python test.py
Traceback (most recent call last):
  File "C:\DEV\Fiverr2025\ORDER\josemariamachad\TEST\test.py", line 39, in <module>
    doc.insert_pdf(fnCover, to_page = 1, start_at = 0)    
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\DEV\.venv\pdf\Lib\site-packages\pymupdf\__init__.py", line 5417, in insert_pdf
    if self._graft_id == docsrc._graft_id:
                         ^^^^^^^^^^^^^^^^
AttributeError: 'str' object has no attribute '_graft_id'

[JorjMcKie]

This is wrong because the first parameter of .insert_pdf() must be a PDF Document, but you are providing a string (the source filename).

[Rapid1898-code]

Oh sorry - i change the code an with this its working:

import os
import sys
import pymupdf
path = os.path.abspath(os.path.dirname(sys.argv[0])) 
fnCover = os.path.join(path, "cover.pdf")
fnInp = os.path.join(path, "inp.pdf")
fnOut = os.path.join(path, "out.pdf")
with pymupdf.open(fnInp) as doc:
  docTitle = pymupdf.open(fnCover)
  doc.insert_pdf(docTitle, to_page = 1, start_at = 0)    
  doc.save(fnOut)

[Rapid1898-code]

But now i have still the problem with the page numbering.

I can open the final output-file with whatever pdf-browser
out.pdf

Allways the first and second page is shown as 1

Is it somehow possible that i insvert the cover site and the numbering is counted for every site from 1 from the beginning
(so the first image is 1 (1 / 34), the second image is 2 (2 / 34) and so on)

[JorjMcKie]

As I have written before: all pages are numbered correctly from 0 to 33 after the insert.
What you refer to as "number" is the page label, not the number.
That's why PDF viewers (at least those working correctly) display "1 (2/34)" or similar. The digit before the expression in the brackets is what the PDF viewer thinks is the label. The actual and final page numbers are shown within the brackets and are correct.

Therefore, if you dislike the result, you must edit the page labels. The simplest solution is removing the labels doc.set_page_labels([]).
The first displayed page will then page 2, which is the original first page.

[Rapid1898-code]

Currently the label is 1, 1, 2
I want to have the labels in the final document be 1,2,3
(and i don´t want to be that it starts with 2 either)

[JorjMcKie]

What is unclear in the documentation of that Document method set_page_labels()?

[JorjMcKie]

There's a lot of flexibility: your new page could have a non-numeric label like "Intro" or Roman number "I", etc.

[Rapid1898-code]

Thanks a lot - set_page_labels did the trick for me -

import os
import sys
import pymupdf
path = os.path.abspath(os.path.dirname(sys.argv[0])) 
fnCover = os.path.join(path, "cover.pdf")
fnInp = os.path.join(path, "inp.pdf")
fnOut = os.path.join(path, "out.pdf")
with pymupdf.open(fnInp) as doc:
  docTitle = pymupdf.open(fnCover)
  doc.insert_pdf(docTitle, to_page = 1, start_at = 0)    
  doc.set_page_labels([])
  doc.save(fnOut)

Now the final document is numbered correct from 1 to x