On Tuesday, 26 July 2022 17:19:04 BST Deri wrote:
> On Tuesday, 26 July 2022 09:00:25 BST joerg van den hoff wrote:
> > me again with an update/correction to the previous description of the
> > issue
> > (the described problem remains, though):
> >
> > 1.
> > regarding the symobl fonts used by grops and gropdf I previously stated
> > the
> > former were using SS (symbols slanted) and the latter S (symbols) which I
> > presumed according to the looks of the greek letters in the ps output
> > (upright) and pdf output (slanted to the right like italics). this was
> > *wrong*. looking into the font information in the formatted files it was
> > the other way around (grops was using SS and gropdf using S).
> >
> > looking into the DESC files, I do find indeed entries
> >
> > grops: fonts 9 0 0 0 0 0 SS S ZD ZDR
> > gropdf: fonts 9 0 0 0 0 0 0 S ZD ZDR
> >
> > which explains the font selection that occurred. I do not understand,
> > however, while this ultimately lead to _slanted_ glyphs with gropdf and
> > _upright_ glyphs with grops (exactly the other way around as I would have
> > expected for S vs SS).
> >
> > 2.
> > forcing grops to also use S (by editing the DESC file and removing SS from
> > the entry) leads to sane ps and pdf output with both devices (no
> > misalignment and strange irregular widths of the greek letters). so this
> > would be the quick patch to "repair" grops: change the DESC file.
> >
> > 3.
> > using now the same font S, the glyphs produced by grops are upright
> > (expected) and those produced by gropdf are slanted (unexpected). why is
> > that??
> >
> > the main observation remains unaltered: in standard setup grops uses SS
> > for
> > typesetting greek letters since SS is found before S according to DESC and
> > this leads to rather massive typesetting errors in equations using
> > possibly
> > many greek letters: cumulative mispositioning of stuff later on the same
> > line.
> >
> > what do to about this?
> >
> > thank you
> > joerg
>
> Hi Joerg,
>
> You are correct that gropdf does not include the SS font. The reason is
> because it is not a proper font, it is instead a postscript program, which,
> when run by a postscript interpreter such as ghostscript or a postscript
> printer, generates a slanted version of the symbol font. This is not valid
> as a pdf font.
>
> The SS font and the S font both define *a but only S defines *A so when they
> are both loaded with .special SS S the lower case is found in SS but
> uppercase in S. Since gropdf does not have SS *a is found in S and a
> special command is sent to gropdf "x Slant 16" which tells it to slant the
> glyph by 16 degrees.
>
> If you type:-
>
> echo "\[*a]" | groff -Z
>
> You will see:-
>
> x T ps
> x res 72000 1 1
> x init
> p1
> x font 11 S
> f11
> s10000
> V12000
> H72000
> md
> DFd
> C*a
> h6310
> n12000 0
> x trailer
> V792000
> x stop
>
> But if you type:-
>
> echo "\[*a]" | groff -Tpdf -Z
>
> It changes to:-
>
> x T pdf
> x res 72000 1 1
> x init
> p1
> x font 11 S
> f11
> s10000
> x Slant 16
