Making more of a PDF visible on screen

[j-t-1]

In Microsoft Edge, you can zoom out using ctrl+-.

Doing this shows more pages on screen like thumbnail view.

How to modify a PDF to do this?

1. pypdf does not have an option to set PageMode to FullScreen in ViewerPreferences?

2. Below does not work, is it my code or pypdf or the PDF processor (Microsoft Edge)?

from pypdf import PdfWriter
from pypdf.constants import PageAttributes
from pypdf.generic import NameObject, NumberObject

writer = PdfWriter(clone_from="./resources/imagemagick-CCITTFaxDecode.pdf")

writer.pages[0][NameObject(PageAttributes.PZ)] = NumberObject(0.1)

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

[stefan6419846]

pypdf does not have an option to set PageMode to FullScreen in ViewerPreferences?

Section 12.2 of the PDF 2.0 specification does not have such an entry. According to section 7.7.2, this would go into the catalog dictionary, which does have the corresponding key.

Below does not work, is it my code or pypdf or the PDF processor (Microsoft Edge)?

This just sets the preferred zoom factor of the page. I do not know if this is the correct way for whatever you are trying to achieve.

[j-t-1]

You are correct, it does not have a key, I misread this not realising it applies when exiting full-screen mode.

Section 12.2, entries in a viewer preferences dictionary for key NonFullScreenPageMode:

(Optional) The document’s page mode, specifying how to display the document on exiting full-screen mode.

Section 7.7 does have the key, but this did not work:

writer._root_object[NameObject("/PageMode")] = NameObject("/FullScreen")

[stefan6419846]

In general, you want to avoid using internal structures - writer.root_object seems what you should use instead. writer.page_mode = "/FullScreen" would be even easier.

Apart from this, you still have not specified what your actual goal is. "Increasing visibility" is something which sounds rather generic.

[stefan6419846]

And by the way: I suspect that especially Microsoft Edge as a web browser would ignore /FullScreen - I have not tested it, but other viewers might respect it.

[j-t-1]

Full screen

writer.page_mode = "/FullScreen"
writer.add_js("app.fullscreen = true;")

Zoom out

writer.root_object.update({
    NameObject("/OpenAction"): ArrayObject([
        writer.pages[0].indirect_reference,
        NameObject("/XYZ"),
        FloatObject(0),
        FloatObject(0),
        FloatObject(0.1)
    ])
})

Neither of these work, and would like to understand why (all tests are on Acrobat Reader):

writer.pages[0][NameObject(PageAttributes.PZ)] = FloatObject(0.1)
writer.add_js("this.zoom = 20;")