[Devel] Re: [Bug-gs] how to recognize GSF?

[Ray Johnston]

Werner,

I went to the address@hidden mailing list to get the context for
this thread. This is part of what I found:

Werner LEMBERG wrote:
> :  But I think it isn't complete solution - it seems (I'm not familiar with
> :  freetype internals, I only looked at it for some time) that it decodes
> :  only binary "Subrs" data, but .gsf files have this data in ascii (hex)
> :  form:
--- SNIP ---
> :  I am not sure that .gsf fonts are valid Type1 fonts ("gsf" means
> :  "ghostscript font"), but I think that if they aren't, freetype should
> :  only return some status indicating non valid font, but not exit with
> :  "Memory fault" and dumped core...
------------
> > > I think it is impossible to recognize GSF since there isn't a
> > > special format or signature.
> >
> > PfaEdit recognizes type1 gsf fonts by finding an unencrypted
> > /CharStrings dictionary (or /Subrs array) definition.
> >
> > But many gsf fonts are type3s and I didn't try to interpret them.
> 
> So the question to the gs maintainers: How can a GSF reliably
> detected?

Why do you need to detect these fonts?

First, there is no requirement that Type 1 fonts have binary Subrs.

The .gsf extension on font files is not indicative of any particular
fomat, but rather just indicates that this font is distributed with
Ghostscript. The /FontType key determines whether the font is Type 1
or Type 3. All are valid PostScript font formats that conform to the
relevant Adobe specification. We were *NOT* trying to create a new
font format.

Regards,
Ray Johnston
Artifex Software Inc.
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