Re: [Heirloom] Using the Symbola font in Heirloom troff

[John Gardner]

> Looking at the postscript output there is a "/uni1F0A1 9429 def" and a
> "/uni1F10A" in a "/Encoding-@15@36 [...] def"; is that part of the font
> machinery?  (I'm sadly ignorant of PostScript, alas.)

Kind of. PostScript predates Unicode, sadly, and has limits on how many
glyphs can be mapped to a single font. To work around this, an *encoding
vector* is used that maps ASCII characters to physical locations in a
loaded font; derivatives of the same font can be generated using different
encoding vectors to workaround these limitations.

Usually, generated PostScript documents will have custom encoding vectors
tailored to the glyphs which are actually used in the text.

On Wed, 5 Aug 2020 at 15:30, T. Kurt Bond <tkurtbond@gmail.com> wrote:

> Looking at the postscript output there is a "/uni1F0A1 9429 def" and a
> "/uni1F10A" in a "/Encoding-@15@36 [...] def"; is that part of the font
> machinery?  (I'm sadly ignorant of PostScript, alas.)
>
> Looking at troff/troff.d/otf.c
> <
> https://github.com/n-t-roff/heirloom-doctools/blob/f3a16e2ba0c411441fd5de5340be73674bd51307/troff/troff.d/otf.c#L1481
> >
> I see that there is a struct WGL
> <
> https://github.com/n-t-roff/heirloom-doctools/blob/f3a16e2ba0c411441fd5de5340be73674bd51307/troff/troff.d/otf.c#L845
> >
> that
> contains female
> <
> https://github.com/n-t-roff/heirloom-doctools/blob/f3a16e2ba0c411441fd5de5340be73674bd51307/troff/troff.d/otf.c#L1481
> >
> and male
> <
> https://github.com/n-t-roff/heirloom-doctools/blob/f3a16e2ba0c411441fd5de5340be73674bd51307/troff/troff.d/otf.c#L1482
> >
> entries.  At the beginning of the struct is a comment
> <
> https://github.com/n-t-roff/heirloom-doctools/blob/f3a16e2ba0c411441fd5de5340be73674bd51307/troff/troff.d/otf.c#L848
> >
> that
> consists of "/* WGL4 */".  Googling that led to Windows Glyph List 4
> <https://en.wikipedia.org/wiki/Windows_Glyph_List_4>.  Taking a leap, I
> added the unicode characters FEMALE SIGN and MALE SIGN to my test
> document.  Those show up fine in the final PDF output.  Maybe this is
> connected?  At this point I suspect without much evidence
> <
> https://github.com/n-t-roff/heirloom-doctools/blob/f3a16e2ba0c411441fd5de5340be73674bd51307/troff/troff.d/otf.c#L1502
> >
> that characters that are not in the StandardStrings
> <
> https://github.com/n-t-roff/heirloom-doctools/blob/f3a16e2ba0c411441fd5de5340be73674bd51307/troff/troff.d/otf.c#L186
> >
> array, the MacintoshStrings
> <
> https://github.com/n-t-roff/heirloom-doctools/blob/f3a16e2ba0c411441fd5de5340be73674bd51307/troff/troff.d/otf.c#L582
> >
> array, or the WGL
> <
> https://github.com/n-t-roff/heirloom-doctools/blob/f3a16e2ba0c411441fd5de5340be73674bd51307/troff/troff.d/otf.c#L848
> >
> array don't get output.  Maybe.  I'll have to investigate some more.
>
> On Tue, Aug 4, 2020 at 11:10 PM Richard Morse <pukku@mac.com> wrote:
>
> > Hm. Just for my edification, I tried a few things.
> >
> > I’m on a Mac, and I don’t know when I compiled Heirloom troff, but it was
> > a year or two ago, so something things may be different.
> >
> > I downloaded the Symbola font from fontlibrary.org. The version I got
> was
> > .ttf, not .otf.
> >
> > The various things that you tried did not work for me either. \[u1F0A1]
> > did work, but that’s because (according to fret, at least), that’s the
> > font’s internal name for the symbol, which is not guaranteed to be true
> > across all fonts, so you can’t really use that for a “fallback” system.
> >
> > Looking at the output of troff without going through dpost, it looks like
> > it is completely ignoring the character. I tried explicitly setting
> > LC_CTYPE to ‘en_US.UTF-8’ and ‘UTF-8’ (both in the terminal, and using
> the
> > .lc_ctype command), but that had no effect.
> >
> > I wonder if troff has a compiled in list of unicode characters that it
> > understands, and if you try to use one it deems invalid it just ignores
> it?
> > (This may be borne out by
> >
> https://github.com/n-t-roff/heirloom-doctools/blob/master/troff/troff.d/unimap.c
> > , but I don’t really know enough about the code to be certain.)
> >
> > Ricky
> >
> > > On Aug 4, 2020, at 10:14 PM, T. Kurt Bond <tkurtbond@gmail.com> wrote:
> > >
> > > In Emacs M-x describe-coding-system tells me the coding system for
> > saving the buffer is utf-8-unix.  I don't have any LC_* environment
> > variables set, but LANG=en_US.UTF-8.
> > >
> > > I'm not very knowledgeable about the insides of Unicode fonts,
> > unfortunately.
> > >
> > > On Tue, Aug 4, 2020 at 4:27 PM Richard Morse <pukku@mac.com> wrote:
> > > Huh. I’m afraid I’m out of my depth then; you might check and see if
> > your LC_* environment variables are set to something incompatible with
> > utf-8 (or, maybe, check and make sure the file in UTF-8, not UCS-16 or
> > something if you’re on Windows), but hopefully someone with more
> experience
> > and knowledge will speak up…
> > >
> > > Ricky
> > >
> > > > On Aug 4, 2020, at 3:59 PM, T. Kurt Bond <tkurtbond@gmail.com>
> wrote:
> > > >
> > > > And if I add "and explicit unicode character reference \U'1F0A1'" to
> > the
> > > > file, that character doesn't show up either.
> > > >
> > > > On Tue, Aug 4, 2020 at 2:47 PM Richard Morse <pukku@mac.com> wrote:
> > > >
> > > >> According to the Heirloom Troff manual, I think that you cannot just
> > > >> insert Unicode characters (although maybe if your LC* environment
> > variables
> > > >> are set correctly, you can?). It says:
> > > >>
> > > >>> Both nroff and troff allow references to specific Unicode
> characters
> > > >> with the \U'X' escape sequence;
> > > >>> it causes the character at position U+X to be printed (X is a
> > > >> hexadecimal number). For troff,
> > > >>> it is required that this character is available in one of the fonts
> > > >> mounted at this point.
> > > >>> As an example, \U'20AC' prints the Euro character €. When register
> > .g is
> > > >> set to 1 Unicode
> > > >>> characters can also be accessed with \[uXXXX] where XXXX is a four
> > digit
> > > >> hexadecimal number.
> > > >>
> > > >> So I think you would need to use `\U'1F0A1'` for the character to
> > show up?
> > > >>
> > > >> Ricky
> > > >>
> > > >>
> > > >>> On Aug 4, 2020, at 12:28 PM, T. Kurt Bond <tkurtbond@gmail.com>
> > wrote:
> > > >>>
> > > >>> (The heirloom-doctools README.md
> > > >>> <
> https://github.com/n-t-roff/heirloom-doctools/blob/master/README.md
> > >
> > > >> says
> > > >>> to ask Heirloom doctools questions on this list.)
> > > >>>
> > > >>> I'd like to use the Symbola font in Heirloom troff.   I tried the
> > > >> following:
> > > >>>
> > > >>> .do xflag 3
> > > >>> .\" fp 5 Optima Optima-Regular ttf
> > > >>> .fp 5 Symbola Symbola otf
> > > >>> .LP
> > > >>> Here is some normal text.
> > > >>> .\" PLAYING CARD ACE OF SPACES is Unicode 0x1F0A1
> > > >>> .ft Symbola
> > > >>> 🂡 And some normal text. ❊
> > > >>> .ft P
> > > >>> More normal text.
> > > >>>
> > > >>> That's a literal PLAYING CARD ACE OF SPADES Unicode character at
> the
> > > >> start
> > > >>> of the line between the two .ft requests.  That character does not
> > show
> > > >> up
> > > >>> in the troff output, even through the EIGHT TEARDROP-SPOKED
> PROPELLER
> > > >>> ASTERISK Unicode character at the end of the line *does* show up,
> > > >>> as CPSuni274A where the CPS<name> outputs the character of that
> name.
> > > >> The
> > > >>> Symbola font is embedded in the PDF output (created from the
> > PostScript
> > > >>> output), and the text "And some normal text" and the EIGHT
> > > >> TEARDROP-SPOKED
> > > >>> PROPELLER ASTERISK Unicode character are in the Symbola font in the
> > troff
> > > >>> output.
> > > >>>
> > > >>> However, if I manually add a CPSuni1F0A1 to the troff output,
> *that*
> > > >> character
> > > >>> *does* show up.
> > > >>>
> > > >>> Any ideas as to why the literal PLAYING CARD ACE OF SPADES Unicode
> > > >>> character in the document source is being ignored and not written
> to
> > the
> > > >>> troff output?
> > > >>>
> > > >>> I actually have a document that needs to use the PLAYING CARD ACE
> OF
> > > >> SPADES
> > > >>> Unicode character.  The ultimate goal is to have the Symbola font
> > used
> > > >> as a
> > > >>> fallback font, which should happen automatically in Heirloom troff,
> > since
> > > >>> it searches all the fonts when a font is missing a character, but I
> > made
> > > >>> the example use the Symbola font directly because that shows the
> > problem
> > > >>> directly.
> > > >>>
> > > >>> --
> > > >>> T. Kurt Bond, tkurtbond@gmail.com, https://tkurtbond.github.io
> > > >>
> > > >>
> > > >
> > > > --
> > > > T. Kurt Bond, tkurtbond@gmail.com, https://tkurtbond.github.io
> > >
> > >
> > >
> > > --
> > > T. Kurt Bond, tkurtbond@gmail.com, https://tkurtbond.github.io
> >
> >
>
> --
> T. Kurt Bond, tkurtbond@gmail.com, https://tkurtbond.github.io
>