Widget font not being updated

[boris-lok-pentadoc]

Description of the bug

After updating Widgets value und calling update() method, the font value is reset, even though the font is present in FormFonts

How to reproduce the bug

Doc: VFNM-2018-05-22-mustervorlage-vorblatt.pdf

import fitz

doc = fitz.open("VFNM-2018-05-22-mustervorlage-vorblatt.pdf")
page = doc[0]
print(doc.FormFonts)
widgets = [i for i in page.widgets()]
print("orig", widgets[0].field_value)

widgets[0].field_value = "Hello! testing"
print("new", widgets[0].field_value)

widgets[0].text_font = "Arial"
print("new font",widgets[0].text_font)

widgets[0].update()
print("after update",widgets[0].field_value)
print("after update", widgets[0].text_font)

PyMuPDF version

1.24.2

Operating system

Linux

Python version

3.11

[JorjMcKie]

This is not a bug. PyMuPDF only supports Helvetica, Times-Roman, Courier and ZapfDingbats as fonts for rendering fields. This is independent from the form fonts that may be already present in the PDF (and which are extracted into FormFonts).

On updating a field, therefore automatically one of the supported 4 fonts is therefore chosen - ignoring any font specification that may already be there.

[boris-lok-pentadoc]

Thank you for your quick reply! I see.

I just found the wording in the documentation regarding it confusing, maybe I could submit a PR for it? It reads as if it is possible to use already embedded FormFonts

When specifying a text font for new or changed widgets, either choose one in the first table column (upper and lower case supported), or one of the already existing form fonts. In the latter case, spelling must exactly match.

To find out already existing field fonts, inspect the list Document.FormFonts.

[JorjMcKie]

I understand the confusion that this may cause. Thank you for your willingness to prepare a change in the documentation. Much appreciated!