How to write the argument of 'fit' in addLink(): PyPDF2

Question

I want to add links to other pages to existing PDF by using PyPDF2. My code works when fit argument is '/Fit', however, I want to use the zoom option. After jump to the added link, pages should be displayed as the size maintained. When fit argument is '/XYZ', how should I supply additional arguments?

from PyPDF2 import PdfFileWriter, PdfFileReader
import io
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import letter


existing_pdf = PdfFileReader(open(r"C:\test.pdf", "rb"))
output = PdfFileWriter()

pageNum = existing_pdf.getNumPages()


for i in range(pageNum):
    if i == 0:
        packet = io.BytesIO()

        can = canvas.Canvas(packet, pagesize=letter)
        can.drawString(523, 45, "")
        can.save()

        packet.seek(0)
        new_pdf = PdfFileReader(packet)

        page = existing_pdf.getPage(i)
        new_pdf = PdfFileReader(packet)
        page2 = new_pdf.getPage(0)
        page.mergePage(page2)
        output.addPage(page)
    else:
        packet = io.BytesIO()

        can = canvas.Canvas(packet, pagesize=letter)
        can.drawString(523, 45, "{}".format(i + 1))
        can.save()

        packet.seek(0)
        new_pdf = PdfFileReader(packet)

        page = existing_pdf.getPage(i)
        new_pdf = PdfFileReader(packet)
        page2 = new_pdf.getPage(0)
        page.mergePage(page2)
        output.addPage(page)
        output.addLink(
            pagenum=i,
            pagedest=0,
            rect=[500, 30, 550, 60],
            border=[0, 0, 0],
            fit="/XYZ",
            0, 0, 1
        )


outputStream = open(r"C:\test_new.pdf", "wb")
output.write(outputStream)
outputStream.close()

Error messages is below:

output.addLink(pagenum=i,pagedest=0,rect=[500,30,550,60],border = [0,0,0],fit="/XYZ",0,0,1)
                                                                                        ^
SyntaxError: positional argument follows keyword argument

Answer 1

This is actually a Python usage issue, not a PyPDF issue.

You are writing

output.addLink(
    pagenum=i,
    pagedest=0,
    rect=[500, 30, 550, 60],
    border=[0, 0, 0],
    fit="/XYZ",
    0, 0, 1  # <---- here is the issue!
)

Hence the pattern function(foo=bar, 0). But Python requires that there are no positional arguments (the zero) after a keyword arguments (foo=bar).

Solution

Although it's not nice, you can make everything positional:

output.addLink(
    i, 
    0,
    [500, 30, 550, 60],
    [0, 0, 0],
    "/XYZ",
    0, 0, 1
)

Answer 2

pdfWriter.addBookmark("Bookmark 1",1, None, None, False, False, '/FitH',1.3)

Please try this snippet, I had this issue too but it is now resolved.