Re: eqn formatting issues with grops and gropdf

[Robert Goulding]

OK, this explains something that has puzzled me. I have installed fonts for
Greek text, and while I get fine output from devps, when I generate a pdf
directly through gropdf, all of the unaccented Greek characters come out
slanted. Attached is an example ms file, and the pdf generated from devps
and ps2pdf, and devpdf, using the free Google font Tinos.

Is there any way to tell grofpdf *not *to slant \(*a etc?

Robert.

On Tue, Jul 26, 2022 at 1:56 PM G. Branden Robinson <
g.branden.robinson@gmail.com> wrote:

> [replying to groff@ from bug-groff@ so more people see this discussion]
>
> I wanted to make sure more people saw this because Deri's explanation is
> gold.  I don't think there's any existing documentation that covers this
> anywhere nearly as lucidly.
>
> Regards,
> Branden
>
> At 2022-07-26T17:19:04+0100, 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
> > V12000
> > H72000
> > md
> > DFd
> > C*a
> > h6310
>


-- 
Robert Goulding
Director, John J. Reilly Center for Science, Technology, and Values;
Director, Program in History and Philosophy of Science;
Assoc. Professor, Program of Liberal Studies,
Fellow, Medieval Institute,
University of Notre Dame.

greek.ms
Description: Binary data

greek-gropdf.pdf
Description: Adobe PDF document

greek-grops.pdf
Description: Adobe PDF document