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
