[luatex] luatex - font encoding for type 1 fonts

[Pali Rohár]

On Sunday 26 June 2016 15:24:11 Hans Hagen wrote:
> On 6/26/2016 1:25 PM, Pali Rohár wrote:
> > But I'm trying to point something else, that csr.enc file does not
> > have to be specified.
> > 
> > File csr.enc contains:
> >   /il2Encoding [
> >   /Gamma /Delta /Theta /Lambda /Xi /Pi /Sigma /Upsilon
> >   ...
> >   /quotedblbase /csquotedblright
> >   ] def
> > 
> > File csr10.pfb contains:
> >   /FontName /csr10 def
> >   /Encoding 256 array
> >   0 1 255 {1 index exch /.notdef put} for
> >   dup 0 /Gamma put
> >   dup 1 /Delta put
> >   dup 2 /Theta put
> >   dup 3 /Lambda put
> >   dup 4 /Xi put
> >   dup 5 /Pi put
> >   dup 6 /Sigma put
> >   dup 7 /Upsilon put
> >   ...
> >   dup 254 /quotedblbase put
> >   dup 255 /csquotedblright put
> >   readonly def
> >   ...
> >   2 index /CharStrings 183 dict dup begin
> >   /Xi {
> >   ...
> >   }
> >   /dotlessi {
> >   ...
> >   }
> >   /oslash {
> >   ...
> >   }
> >   ...
> > 
> > So glyphs are really in random order in csr10.pfb file (first is
> > /Xi, second /dotlessi, ...) but at beginning of csr10.pfb file is
> > /Encoding table where is that mapping from index to glyph name.
> > Same what is in csr.enc file.
> > 
> > And I'm trying to tell you that in this case (when /Encoding array
> > in pfb file is available), external *.enc is not needed to
> > specify. Looks like that pdftex uses this /Encoding array.
> 
> the enc files shows what glyphs (by name) are in the tfm file and the
> vector in the pfb file tels what glyphs (by name) are in what slot ..
> these are different indexes and the name makes it possibel to go from
> the tex one to the pfb one
> 
> (for adobe standard encoding it in parallel but tex encodings are
> hardly standard)

So above /Encoding 256 array in PFB file can be different as encoding 
vector in ENC file? I thought that they should be same...

Anyway I tested pdftex and it does *not* use ENC file, encoding takes 
from /Encoding 256 array from PFB file. And Linux strace program proved 
that no enc file was opened during pdftex run.

So to mimic pdftex behaviour (and how CSFonts Type 1 are read/parsed) I 
would really propose to use /Encoding 256 array from PFB file when ENC 
file for font loader is not specified.

Meaning: Use ENC file if possible, but when user not specified it --> 
fallback to /Encoding array in PFB file.

> > I think it could be useful if that your loader was able to
> > understand command also when pfb file is not specified. It could
> > try to load either pfb file (preferred) or fallback to
> > PK/metafont.
> 
> the more hardcoded logic is in there, the harder it is to beat (i can
> impose some logic in context but want to stay away from intefreing in
> other macro packages logic)
> 
> > it has (internal/system pdftex.map) database of Type 1 fonts and
> 
> only system .. in luatex i never use map files

Ok, so luatex ignores any specified map files?

-- 
Pali Rohár
pali.rohar at gmail.com
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