\DocumentMetadata{lang=en-GB}
\documentclass[paper=a4]{scrartcl}
% Packages
\usepackage{graphics, array}
\usepackage[dvipsnames]{xcolor}
\usepackage[hypcap=false]{caption}
\usepackage{shortvrb}
\usepackage{yfonts-otf}
\usepackage{fourier-otf}
\setmonofont{Inconsolatazi4}[Scale=MatchLowercase,
                             HyphenChar=None,StylisticSet={2,3}]
\usepackage[german,british]{babel}
\babeltags{de=german}
\usepackage[english]{varioref}
\usepackage{realscripts}
\usepackage{microtype}
\usepackage{hyperref}
\hypersetup{pdftitle={yfonts-otf User’s Guide},
            pdfauthor={Daniel FLIPO},
            colorlinks
            }
\newcommand*{\hlabel}[1]{\phantomsection\label{#1}}
%
\MakeShortVerb{\|}

%verbatim : modifier  \verbatim@font
\def\ColorVerb{\color{MidnightBlue}}
\makeatletter
\let\verbatim@fontORI\verbatim@font
\def\verbatim@font{\ColorVerb\verbatim@fontORI}
\makeatother

\newcommand*{\pkg}[1]{\texttt{\ColorVerb #1}}
\newcommand*{\opt}[1]{\texttt{\ColorVerb #1}}
\newcommand*{\file}[1]{\texttt{\ColorVerb #1}}
\newcommand*{\cmd}[1]{\texttt{\ColorVerb \textbackslash #1}}
\newcommand*{\family}[1]{\textit{#1}}
\newcommand*{\MF}{\textsf{Metafont}}

\title{OpenType version of yfonts for Old German}
\author{\href{mailto:daniel.flipo@free.fr}{Daniel \textsc{Flipo}}}
\newcommand*{\version}{0.61}

\begin{document}
\maketitle
\thispagestyle{empty}

\begin{abstract}
  This bundle provides OpenType versions of the Old German fonts \family{yfrak},
  \family{ygoth} and \family{yswab} designed by Yannis Haralambous in \MF{}
  (1990).

  A style file \file{yfonts-otf.sty} is included to load these fonts easily;
  it is meant as a replacement for LuaLaTeX and XeLaTeX of
  \file{yfonts.sty}.

  A Type\,1 version of these fonts has been provided by Thorsten Bronger (2002).

  The \family{yinit} font (initials) is already available as in OpenType format,
  thanks to Élie Roux.

  Please beware of the \emph{experimental} status of the current
  version~(\version).

  All three fonts are covered by OFL licence, style file and documentation
  are under LPPL-1.3 licence.
\end{abstract}

\section{Usage}

\pkg{yfonts-otf.sty} loads \pkg{fontspec} and mimics what the
\pkg{yfonts} package does for the  Type\,1 version: it defines three font
families |\frakfamily|, |\gothfamily| and |\swabfamily| and the corresponding
commands with arguments |\textgoth{}|, |\textfrak{}|, and |\textswab{}|.

All three families are loaded with all ligatures activated, an |s|
automatically prints a long~\textfrak{ſ} (initial and middle form) or a
round~{\frakfamily{s\hspace{1sp}}} (final form)%
\footnote{See section~\ref{sec:long-s} for details.}.
Coding |"a|, |"e|, |"o|, |"u|, |"s| is only supported through Babel’s
German shorthands to produce \textfrak{ä, ë, ö, ü, ß}.
Nowadays, most keyboards give access to the Unicode characters |ä|,
|ë|, |ö|, |ü| and |ß|, so typing them directly is a better alternative.

In the \family{yfrak} family, the command |\etc| prints {\etc}
a variant of the \textfrak{uſw} abbreviation while |\Jvar| prints {\Jvar}
a variant of \textfrak{J} (suggestion of Daniel Sanders, mentioned by Yannis).

The OpenType feature |Alternate=0| turns \textfrak{ä, ë, ö, ü} into
{\frakfamily\addfontfeature{Alternate=0} ä, ë, ö, ü}.
It works for the \family{yfrak} and \family{yswab} families but not for
\family{ygoth} (variant not available in the original version).

|\textfrak{Ä Ö Ü}| prints \textfrak{Ä Ö Ü} unless OpenType
feature |Alternate=1| is required, then the output is
{\frakfamily\addfontfeature{Alternate=1} Ä Ö Ü}.
It works for the \family{yfrak}, \family{yswab} and \family{ygoth}
families.

The \family{yswab} family offers |CharacterVariant=1| (|+cv01|) and
|CharacterVariant=2| (|+cv02|) which respectively change the exclam and
question marks:
{\swabfamily !} into {\swabfamily\addfontfeature{CharacterVariant=1}!}
and {\swabfamily ?} into {\swabfamily\addfontfeature{CharacterVariant=2}?}.

Used with the \family{ygoth} family, the |StylisticSet=1| (|+ss01|)
feature provides variants for the long~s and its ligatures:
{\gothfamily ſ, ſi, ſſ, ſſi, ſt} are turned into
{\gothfamily\addfontfeature{CharacterVariant=1} ſ, ſi, ſſ, ſſi, ſt}.

These features can be added locally anywhere in the document body, f.i.:\\
|\frakfamily\addfontfeature{Alternate=0}|\\
or using \pkg{yfonts-otf.sty}’s options \opt{oldumlaut}(alias |Alternate=0|)
and \opt{gothvarlongs}, f.i.:\\
|\usepackage[oldumlaut,gothvarlongs]{yfonts-otf}|\\
\opt{oldumlaut} applies globally to both \family{yfrak} and \family{yswab}
families, \opt{gothvarlongs} applies only to \family{ygoth} family.
Option \opt{modernumlaut} passed to \pkg{yfonts-otf.sty} is equivalent to
|Alternate=1|.

It is also possible to use these fonts without loading \pkg{yfonts-otf.sty},
then I recommend to call them by \emph{file name}, as XeTeX cannot find fonts in
the texmf tree by \emph{font name}%
\footnote{Unless they have been declared as \emph{System} fonts…}, f.i.:\\
|\setmainfont{yfrak.otf}[|\texttt{\ColorVerb<options>}|]|
or |\fontspec{yswab.otf}[|\texttt{\ColorVerb<options>}|]|, this
will work with both LuaTeX and XeTeX.

\section{Coding the long/round s}
\label{sec:long-s}

The traditional German rules for long ({\frakfamily ſ\kern1pt}) and
round ({\frakfamily\shorts}) are somewhat complex,
a summary can be found in the Unifraktur Maguntia Manual
(\file{Dokumentation\_en\_fraktur.pdf}, \cite{UF}).

\pkg{yfonts-otf} borrows the automatic choice from the Unifraktur Maguntia
fonts. It uses OpenType features (|ss11|), according to the authors it fails
in less than 1~\% of the occurences.
When the algorithm fails, it is possible to force a round s
(coding |s=| or |\shorts|)  or a long~ſ (coding {\ColorVerb ſ}\,%
\footnote{On Unix systems the \opt{Compose} key can be used:
    \opt{Compose f s}.}
or |\longs|).

Loading the \pkg{yfonts-otf} package activates the |ss11|
feature unless option \opt{gothvarlongs} is added, then the |ss01| is
activated instead (together with |cv01|) for the \family{ygoth} family so that
the long~ſ and its ligatures are printed as
{\gothfamily\addfontfeature{CharacterVariant=1} ſ, ſi, ſſ, ſſi, ſt}
instead of {\gothfamily ſ, ſi, ſſ, ſſi, ſt} (default).

Aliases are provided for these features:
|Style=longs| for |StylisticSet=11| (|+ss11|) and
|Style=gothvarlongs| for |StylisticSet=1| (|+ss01|).

Experts might want to type {\ColorVerb ſ} (U+17F) or {\ColorVerb s}
(U+073) to keep the full control of the {\ColorVerb s} form; this requires
either to deactivate the |ss11| feature after loading the \pkg{yfonts-otf}
package, or to use a direct |\setmainfont{}[]| or |\fontspec{}[]| call.
Feature |CharacterVariant=1| (|+cv01|) may be used for the \family{ygoth}
family to get the long~ſ variant
{\gothfamily\addfontfeature{CharacterVariant=1} ſ, ſi, ſſ, ſſi, ſt}
instead of {\gothfamily ſ, ſi, ſſ, ſſi, ſt}.

%\newpage
\section{List of optional ligatures}

Ligatures are split into three groups which may be deactivated globally or
inside a group with the command
|\addfontfeature{RawFeature=-|\textit{\ColorVerb ligname}|}|%
\footnote{\pkg{yonts-otf} specifically defines \cmd{ZWNJ} (\cmd{char"200C}) to
  break unwanted ligatures: {\frakfamily ent\ZWNJ{}ziffern} (no {\frakfamily tz}
  lig) can be coded \texttt{\ColorVerb ent\cmd{ZWNJ} ziffern} or
  \texttt{\ColorVerb ent\cmd{ZWNJ}\{\}ziffern}.}

\vspace{\baselineskip}
|\frakfamily| : \let\ffam\frakfamily
\begin{tabular}{>\rmfamily l|l| l}
  \hline
  Name & Default ($+$) & Optional ($-$) \\
  \hline
  rlig & \ffam ch, ck, st, tz
       &\ffam\addfontfeature{RawFeature=-rlig} ch, ck, st, tz \\
  liga &\ffam ff, fi, fl, ffi, ffl, sf, ſſ
       &\ffam\addfontfeature{RawFeature=-liga}
              ff, fi, fl, ffi, ffl, sf, ſſ \\
  \hline
\end{tabular}

\vspace{.5\baselineskip}
|\swabfamily| : \let\ffam\swabfamily
\begin{tabular}{>\rmfamily l|l| l}
  \hline
  Name & Default ($+$) & Optional ($-$) \\
  \hline
  rlig &\ffam ch, ck, st, tz
       &\ffam\addfontfeature{RawFeature=-rlig} ch, ck, st, tz \\
  liga &\ffam ff, fi, fl, ffi, ffl, sf, ſſ
       &\ffam\addfontfeature{RawFeature=-liga}
              ff, fi, fl, ffi, ffl, sf, ſſ \\
  \hline
\end{tabular}

\vspace{.5\baselineskip}
|\gothfamily| : \let\ffam\gothfamily
\begin{tabular}{>\rmfamily l|l| l}
  \hline
  Name & Default ($+$) & Optional ($-$) \\
  \hline
  rlig &\ffam ch, ck, st, {\addfontfeature{StylisticSet=1} st}, tz
       &\ffam\addfontfeature{RawFeature=-rlig}
              ch, ck, st, {\addfontfeature{StylisticSet=1} st}, tz\\
  liga &\ffam ct, ff, fi, fl, ffi, ffl, ij, ll,
       &\ffam\addfontfeature{RawFeature=-liga}
              ct, ff, fi, fl, ffi, ffl, ij, ll,\\
       &\ffam  ſſ, ſi, ſſi,
         \addfontfeature{RawFeature=+cv01}ſſ, ſi, ſſi,
       &\ffam\addfontfeature{RawFeature=-liga} ſſ, ſi, ſſi,
         \addfontfeature{RawFeature=-liga;+cv01} ſſ, ſi, ſſi,
       \\
  hlig &\ffam ba, be, bo, da, de, do, ha, he, ho,
       &\ffam\addfontfeature{RawFeature=-hlig}
              ba, be, bo, da, de, do, ha, he, ho, \\
       &\ffam pa, pe, po, pp, qq, va, ve, vu
       &\ffam\addfontfeature{RawFeature=-hlig}
              pa, pe, po, pp, qq, va, ve, vu\\
  \hline
\end{tabular}

\section{Samples}

A practical usage of these fonts can be found in file \file{Erlkonig.ltx} to
be compiled with \pkg{lualatex}.
It shows the beginning of Goethe’s Erlkönig poem typeset with each of them.

\section{Compatibility with other packages}

\begin{description}
\item[\pkg{microtype}] is compatible with \pkg{yfonts-otf} (protusion,
  expansion and letter spacing) but as we have no specific \file{mt-*.cfg}
  config file yet for the yfonts\footnote{Contributions welcome!},
  adding\\
  |\DeclareMicrotypeAlias{yfrak.otf}{TU-basic}|\\
  |\DeclareMicrotypeAlias{yswab.otf}{TU-basic}|\\
  |\DeclareMicrotypeAlias{ygoth.otf}{TU-basic}|\\
  after loading \pkg{microtype} is recommended to avoid (lots of) warnings
  about missing characters.

\item[\pkg{soul}] is old (2003) and not recommended for OpenType fonts.
  Its command |\so{}| brakes ligatures (f.i. |\so{Wasser}|), for
  letter spacing \pkg{microtype}’s command |\textls{}| should be preferred.
  With LuaTeX, \pkg{lua-ul} is a much better choice for striking or
  underlining.

\end{description}

\section{Acknowledgements}

Great thanks to Keno Wehr for carefully testing the initial version and
making valuable suggestions for improvements.

\enlargethispage*{\baselineskip}
\begin{thebibliography}{99}
\bibitem{YH} Typesetting Old German: Fraktur, Schwabacher, Gotisch and
  Initials, \\ \textit{Yannis Haralambous},
  \href{https://www.tug.org/TUGboat/tb12-1/tb31hara.pdf}%
  {TUGboat 12\#1 (1991), pages 129–138}.

\bibitem{WS} The \pkg{yfonts} package for use with \LaTeXe,
  \textit{Walter Schmidt}, (2019).

\bibitem{UF} The \href{https://sourceforge.net/projects/unifraktur/}%
  {Unifraktur Maguntia} TrueType fonts (2017).
\end{thebibliography}

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\end{document}

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