Woff2 file has different checksum each time it is saved.

[inklinea]

I'm using fonttools 4.29.1 with python 3.10.12.
Ubuntu 22
``
For this simple code:

font_object = TTFont(ttf_filepath)
font_object.flavor = 'woff2'
font_file_disk = f'/filepath/{font_name}.woff2'
font_object.save(font_file_disc)

The checksum of the woff2 file changes every time the same font is saved.
I not sure why this is ?

At a guess I think it might be due to the way Brotli compresses to woff2, and the compression although valid is not the exactly the same each time ?

I'm converting the woff2 font into a base64 @font-face for use on the web.

If I can have the same base64 string each time, it gives a simple way to check if the document already contains this font (even if the name is different)

Many thanks for any advice.

[Lorp]

More likely to be the timestamps in the head table.

[Lorp]

If you use the command line tool woff2_compress, the resulting WOFF2 file will be identical each time.

[inklinea]

Fantastic, thanks for your quick response.

All I needed was

font_object.recalcTimestamp = False

and the problem is solved :)

[Lorp]

Great!