Re: [ft-devel] FT_Get_PS_Font_Private in CFF driver

[Werner LEMBERG]

> I need it for filling out a font descriptor in a PDF (it's the StemV
> value of the dictionary).  By requiring that my CFF font files
> contain exactly one font, they can be embedded directly in the PDF
> (the PDF spec has this requirement, p 468 in the 1.7 version).

OK.

>> Yes, sub-fonts are ignored.  However, they aren't needed since only
>> the information of the top-level font info dictionary is returned.
> 
> Okay, I must have misread the CFF spec then. I thought the font info
> dict was per font as well (and eg UnderlineThickness sounds parallel
> to StdVW in this regard, doesn't it?).

The structure of a CIDFont is as follows:

  Top DICT: version
            Notice
            Copyright
            FontName
            ...
            FDArray

  FDArray: Font DICT 0
           Font DICT 1
           ...

  Font DICT 0: Font Dict data
               Private Dict data

  Font DICT 1: Font Dict data
               Private Dict data

  ...

For example, the `FontName' entry is present in the Top DICT and in
all Font DICT entries indexed in the FDArray.

> The implementation I suggest would then only be as bad as the
> current implementation of FT_Get_PS_Font_Info.  To do better, the
> api needs to have the sub-font index as a parameter.

Well, FT_Get_PS_Font_Info isn't bad at all, since it correctly returns
the Top DICT data of a CIDFont which represents the `public'
dictionary data.  However, the FDArray data is *completely internal*
to FreeType and not publicly visible.  It is *not* possible to
directly access a CIDFont's subfont.  In other words, your suggestion
of using a subfont index doesn't work.

I'll ask someone from Adobe which value is used for StemV if the
particular font is a CIDFont.


    Werner