Information on character (fontname, adv) #460

EmanueleGusso · 2021-07-02T10:28:24Z

EmanueleGusso
Jul 2, 2021

Hi everybody,
I would need some explainations about two properties of the characters.
In particular:

I've noticed that the fontnames (e.g. 'BCDEEE+Calibri', 'BCDFEE+Calibri-Bold', 'ADUOFK+TheSansSemiBold-Plain') always have a string followed by "+". I've searched online but nobody knows what that string (e.g. 'ADUOFK') is. Do you have any idea?
The second question instead is related to the formula used to get adv. I don't get what this value actually represent. Isn't the "size" of the char sufficient?

Thank you very much for your availability!

Answered by samkit-jain

You may refer to section 9.6.4 (page 266) of the PDF 1.7 specification. Those 6 random uppercase letters represent the tag for the font subtype.
pdfplumber relies on pdfminer.six for reading the PDFs and the field adv is generated by it and not pdfplumber just to clarify. The calculation can be found here and represents the scaled width of a character. I am not sure but I think it is mainly used when converting PDF to HTML.

samkit-jain · 2021-07-02T17:58:11Z

You may refer to section 9.6.4 (page 266) of the PDF 1.7 specification. Those 6 random uppercase letters represent the tag for the font subtype.
pdfplumber relies on pdfminer.six for reading the PDFs and the field adv is generated by it and not pdfplumber just to clarify. The calculation can be found here and represents the scaled width of a character. I am not sure but I think it is mainly used when converting PDF to HTML.

0 replies