gtabs.sty

% package info and requirements:
\NeedsTeXFormat{LaTeX2e}
\def\gcs@date{2023/02/26}
\def\gcs@version{v0.1}
\def\gcs@description{Guitar Tabs with TikZ (CN)}

\ProvidesPackage{gtabs}[\gcs@date\space \gcs@version\space \gcs@description]

\RequirePackage{tikz,cnltx-base}
\usetikzlibrary{shapes.misc,arrows,calc}
% --------------------------------------------------------------------------
% message handling
\newcommand*\gcs@error@message{%
    For details have a look at the `guitarchordschemes' manual.%
}

\cnltx@create@generic@message{gcs}{gtabs}{Error}{\gcs@error@message}
\cnltx@create@generic@message{gcs}{gtabs}{Warning}{}
\cnltx@create@generic@message{gcs}{gtabs}{WarningNoLine}{}
\cnltx@create@generic@message{gcs}{gtabs}{Info}{}

\newcommand*\gcs@missing@date@error[2]{%
    \gcs@error
    {#1: empty #2}
    {#1: It seems you didn't specify the #2}%
}

\newrobustcmd*\gcs@def[1]{%
    \ifdef{#1}
    {%
        \gcs@error
        {The macro \string#1\space is already defined}
        {%
            The macro \string#1\space is already defined. Please let the package
            author know%
        }%
    }
    {\protected\def#1}%
}

\newrobustcmd*\gcs@deprecated@option[2]{%
    \gcs@warning{Since version #1 the option `#2' has been dropped}%
}

% --------------------------------------------------------------------------
% package options and setup:
\newcommand*\gcs@finger@font{\sffamily\small}
\newcommand*\gcs@position@font{\sffamily}
\newcommand*\gcs@string@name@format{\sffamily\small}

\newcommand*\gcs@x@unit{.8cm}
\newcommand*\gcs@y@unit{.8cm}
\newcommand*\gcs@line@width{1pt}
\newcommand*\gcs@finger@radius{.1875}
\newcommand*\gcs@finger@x@offset{.375}
\newcommand*\gcs@finger@y@offset{.275}
\newcommand*\gcs@angle{0}

\newcommand*\gcs@string@number{6}
\newcommand*\gcs@setstringnumber[1]{%
    \ifnumless{#1}{1}
    {%
        \gcs@warning{You can't use less than one string. Setting string number
            to 1}%
        \def\gcs@string@number{1}%
    }
    {%
        \ifnumgreater{#1}{7}
        {%
            \gcs@warning{You can't use more than seven
                strings. Setting string number to 6}%
            \def\gcs@string@number{6}%
        }
        {\def\gcs@string@number{#1}}%
    }%
}

\newcommand*\gcs@chordscheme@fret@number{4}

\newbool{gcs@restrict@boundingbox}
\newcommand*\gcs@restrictboundingbox[1]{
    \ifbool{gcs@restrict@boundingbox}
    {
        \ifnumequal{\gcs@string@number}{1}
        {\useasboundingbox (0,-.4) --++ (1.5*\csname gcs@#1@fret@number\endcsname,.8) ; }
        {
            \useasboundingbox
            (bass)
            rectangle
            (1.5*\csname gcs@#1@fret@number\endcsname,{.8*(\gcs@string@number-1)}) ;
        }
    }{}
}

\pgfkeys{
    gtabs/.cd ,
    x-unit/.code              = \def\gcs@x@unit{#1} ,
    y-unit/.code              = \def\gcs@y@unit{#1} ,
    rotate/.code              = \def\gcs@angle{#1} ,
    strings/.code             = \gcs@setstringnumber{#1} ,
    finger-format/.code       = \def\gcs@finger@font{#1} ,
    finger-format+/.code      =
    \expandafter\def\expandafter\gcs@finger@font
    \expandafter{\gcs@finger@font#1} ,
    position-format/.code     = \def\gcs@position@font{#1} ,
    position-format+/.code    =
    \expandafter\def\expandafter\gcs@position@font
    \expandafter{\gcs@position@font#1} ,
    chord-frets/.code         =
    \ifnumless{#1}{4}
    {%
        \gcs@warning{You cannot use less than 4 frets for a chord!}%
        \def\gcs@chordscheme@fret@number{4}%
    }
    {\def\gcs@chordscheme@fret@number{#1}} ,
    line-width/.code          = \def\gcs@line@width{#1} ,
    finger-radius/.code       = \def\gcs@finger@radius{#1} ,
    finger-x-offset/.code     = \def\gcs@finger@x@offset{#1} ,
    finger-y-offset/.code     = \def\gcs@finger@y@offset{#1} ,
    finger-style/.code        = \tikzset{finger style/.style={#1}} ,
    ringing-style/.code       = \tikzset{ringing style/.style={#1}} ,
    muted-style/.code         = \tikzset{muted style/.style={#1}} ,
    restrict-bounding-box/.is if = gcs@restrict@boundingbox
}

% the setup command:
\newrobustcmd*\setchordscheme[1]{\pgfqkeys{/gtabs}{#1}}

% some defaults -- need to be set before options are processed:
\setchordscheme{
    muted-style     = {cross out,draw} ,
    ringing-style   = {draw} ,
    finger-style    = {fill}
}

\ProcessPgfOptions*

% --------------------------------------------------------------------------
% settings for the whole scheme:
\tikzset{
    gcs/finger/.style =
        {
            xshift = \gcs@finger@x@offset*\gcs@x@unit ,
            yshift = \gcs@finger@y@offset*\gcs@y@unit ,
            font   = \gcs@finger@font
        }
}

% setting a chord scheme:
\pgfkeys{
    gcs/chord/.cd ,
    position/.code  = \def\gcs@chord@position{#1} ,
    finger/.code    = \gcs@chord@finger{#1} ,
    mute/.code      = \gcs@chord@mute{#1} ,
    ring/.code      = \gcs@chord@ring{#1} ,
    barre/.code     = \gcs@chord@barre{#1} ,
    fret-number/.code  =
    \ifnumless{#1}{4}
    {%
        \gcs@warning{You cannot use less than 4 frets for a chord!}%
        \def\gcs@chordscheme@fret@number{4}%
    }
    {\def\gcs@chordscheme@fret@number{#1}}
}

% --------------------------------------------------------------------------
% the internal commands

% placing fingers:
%   <fret>/<string>:<finger>
\newrobustcmd*\gcs@chord@finger[1]{%
    \foreach \gcs@finger@spec in {#1}
        {
            \expandafter\gcs@get@finger@data\gcs@finger@spec::\q@stop
            \ifdefvoid\gcs@finger@x
            {\gcs@missing@date@error{finger}{position}}
            {
                \pgfmathsetmacro\gcs@finger@fret{1.5*\gcs@finger@x-0.75}
                \ifdefvoid\gcs@finger@y
                {\gcs@missing@date@error{finger}{string}}
                {
                    \pgfmathsetmacro\gcs@finger@string{(\gcs@string@number-\gcs@finger@y)*4/5}
                    \draw[finger style]
                    (\gcs@finger@fret,\gcs@finger@string)
                    circle
                    (\gcs@finger@radius*\gcs@x@unit) ;
                    \node[gcs/finger]
                    at (\gcs@finger@fret,\gcs@finger@string)
                    {\gcs@finger@number} ;
                }
            }
        }
}
\let\gcs@scales@finger\gcs@chord@finger

\gcs@def\gcs@get@finger@data#1/#2:#3:#4\q@stop{%
    \def\gcs@finger@x{#1}%
    \def\gcs@finger@y{#2}%
    \def\gcs@finger@number{#3}%
}

% placing a barre:
%   <fret>/<string>-<string>:<finger>
\newrobustcmd*\gcs@chord@barre[1]{%
    \foreach \gcs@barre@spec in {#1}
        {
            \expandafter\gcs@get@barre@data\gcs@barre@spec::\q@stop
            \ifdefvoid\gcs@barre@x
            {\gcs@missing@date@error{barre}{position}}
            {\pgfmathsetmacro\gcs@barre@fret{1.5*\gcs@barre@x-0.75}}
            \ifdefvoid\gcs@barre@fromto
            {\gcs@missing@date@error{barre}{string range}}
            {
                \expandafter\gcs@barre@getstrings\gcs@barre@fromto--\q@stop
                \pgfmathsetmacro\gcs@barre@lower@string{(\gcs@string@number-\gcs@barre@lower@y)*4/5}
                \pgfmathsetmacro\gcs@barre@upper@string{(\gcs@string@number-\gcs@barre@upper@y)*4/5}
                \draw[finger style,round cap-round cap,line width=2*\gcs@finger@radius*\gcs@x@unit]
                (\gcs@barre@fret,\gcs@barre@lower@string) node[gcs/finger] {\gcs@barre@finger}
                ++ (0,\gcs@finger@radius*\gcs@x@unit)
                --
                ($(\gcs@barre@fret,\gcs@barre@upper@string)+(0,-\gcs@finger@radius*\gcs@x@unit)$)
                ;
            }
        }
}

\gcs@def\gcs@get@barre@data#1/#2:#3:#4\q@stop{%
    \def\gcs@barre@x{#1}%
    \def\gcs@barre@fromto{#2}%
    \def\gcs@barre@finger{#3}%
}

\gcs@def\gcs@barre@getstrings#1-#2-#3\q@stop{%
    \ifx#3-\relax
        \def\gcs@barre@lower@y{#1}%
        \def\gcs@barre@upper@y{#2}%
    \else
        \gcs@error
        {barre: wrong string range syntax}
        {barre: wrong string range syntax}%
    \fi
}

% muted strings:
\newrobustcmd*\gcs@chord@mute[1]{%
    \foreach \muted@string in {#1}
        {
            \pgfmathsetmacro\muted@string@pos{(6-\muted@string)*4/5}
            \node[muted style] at (-1,\muted@string@pos) {} ;
        }
}

% ringing strings:
\newrobustcmd*\gcs@chord@ring[1]{%
    \foreach \ringing@string in {#1}
        {
            \pgfmathsetmacro\ringing@string@pos{(\gcs@string@number-\ringing@string)*4/5}
            \draw[ringing style]
            (-1,\ringing@string@pos) circle (\gcs@finger@radius*\gcs@x@unit) ;
        }
}

% --------------------------------------------------------------------------
% the chord scheme command:
\newrobustcmd*\gcs@chordscheme[1]{%
    \begingroup
    \begin{tikzpicture}[
            x=\gcs@x@unit,
            y=\gcs@y@unit,
            line width=\gcs@line@width,
            baseline=(bass)
        ]
        \begin{scope}[rotate=\gcs@angle,local bounding box=diagram]
            \coordinate (bass) at (0,0) ;
            \gcs@restrictboundingbox{chordscheme}
            \pgfqkeys{/gcs/chord}{#1}%
            \foreach \fretnumber
            in {0,...,\gcs@chordscheme@fret@number}
            {
                \ifnumequal{\gcs@string@number}{1}
                {
                    \draw (1.5*\fretnumber,-.4) --++ (0,.8) ;
                }
                {
                    \ifnumequal{\fretnumber}{0}
                    {
                        \ifdefvoid\gcs@chord@position
                        {
                            \draw[ultra thick] (1.5*\fretnumber-0.1,-0.025) -- ++(0,{.8*(\gcs@string@number-1) + 0.05}) ;
                        }
                        {
                            \draw (1.5*\fretnumber,-0.025) -- ++(0,{.8*(\gcs@string@number-1) + 0.05}) ;
                        }
                    }
                    {
                        \ifnumequal{\fretnumber}{\gcs@chordscheme@fret@number}
                        {}
                        {
                            \draw (1.5*\fretnumber,-0.025) -- ++(0,{.8*(\gcs@string@number-1) + 0.05}) ;
                        }
                    }
                }
            }
            \foreach \gcs@string in {1,...,\gcs@string@number}
            {
                \draw
                (0,{.8*(\gcs@string@number-\gcs@string)})
                node[transform shape,
                    label={[text height=1.5ex,text depth=.2ex]left:%
                            \gcs@string@name@format\csuse{guitar@string@\gcs@string}}] {}
                --++(1.5*\gcs@chordscheme@fret@number,0) ;
            }
            \ifdefvoid\gcs@chord@position
            {}
            {
                \draw
                (.75,{0.1*(\gcs@string@number-1)})
                node[transform shape,
                    label={[text height=1.5ex, font=\gcs@position@font]%
                            below:\gcs@chord@position}] {} ;
            }
        \end{scope}
    \end{tikzpicture}
    \endgroup
}

% --------------------------------------------------------------------------
% the user commands:
\newrobustcmd*\chordscheme[1][]{\gcs@chordscheme{#1}}

% --------------------------------------------------------------------------
% the symbols for use outside of a scheme:
\newrobustcmd*\gcs@fingersymbol{%
    \tikz\draw[finger style] (0,0) circle (\gcs@finger@radius*\gcs@x@unit);}

\newrobustcmd*\ringingstring{%
    \tikz\draw[
        ringing style,
        line width=\gcs@line@width] (0,0) circle (\gcs@finger@radius*\gcs@x@unit);}

\newrobustcmd*\mutedstring{%
    \tikz\node[
        muted style,
        line width=\gcs@line@width] at (0,0) {};}

\endinput