Re: [Freetype] FT_Attach_File, .afm, .pfa, .pfb, etc

[Pavel Kankovsky]

On Mon, 21 Jan 2002, Ian Britten wrote:

> - It seems that the .pfa/.pfb files are basically the same, except that one
>   is ascii and one is binary.  Correct?

Exactly. In fact, there is a utility out there that can convert pfa to pfb
and vice versa.

>   Is one 'better' than the other?

Well, pfb file is smaller, pfa

> - The .afm file seems to contain 'extra' stuff, such as kerning info, etc.
>   It seems that the .afm file would be needed to get logically correct 
>   results from Freetype, and that I might want to skip fonts that don't have
>   an AFM file?  Maybe?

The metric (afm) is not necessary if you can live without kerning.

> I discovered FT_Attach_File, which indicates it is for use for fonts that
> are spread across multiple files.

Yes.

> Do I (Should I) attach a .pfb to a .pfa?

No.

> Does it matter what I attach a .afm file to?

Yes. It will make the kerning info available.

> Does Freetype automatically attach any files (ie If they're in the
> same directory), or do I need to do it all explicitely myself?

No and yes.

> As to some specific examples I've run into:
> - Consider the 'Bitstream Charter Bold' (AKA CharterBT-Bold) font.  I've
>   discovered that XFree86-4.0.1-28mdk installs
>   /usr/X11R6/lib/X11/fonts/Type1/c0632bt_.pfb, while
>   ghostscript-fonts-5.50-5mdk installs
>   /usr/share/fonts/default/ghostscript/bchb.pfa AND
>   /usr/share/fonts/default/ghostscript/bchb.afm
> 
>   Should these be considered the same fonts?

Who knows? It would be really nasty if two different fonts were hiding
under one name but there is still some space for "diversity"--for
instance, one of the fonts may contain more glyphs than the other (URW++
did this with GS fonts--later releases cover ISO 8859-2 while earlier do 
not).

> Can I 'attach' the AFM to either one?

Yes, if those two fonts (c0632bt_.pfb and bchb.pfa) are identical or
almost identical.

--Pavel Kankovsky aka Peak  [ Boycott Microsoft--http://www.vcnet.com/bms ]
"Resistance is futile. Open your source code and prepare for assimilation."