Distribute large Tikz image on two A4 landscape

Question

How do I distribute the following picture in such a way that

1. it is printed on two A4 landscape
2. 1cm in the centre repeat itself (that is, the right most cm on the first page is equal to the left most cm on the second page)

\documentclass{article}
\usepackage[a4paper,margin=.5cm,landscape]{geometry}
\usepackage{etex}
\usepackage{tikz}
\usepackage{musixtex}
\def\threedp#1{\pgfmathparse{#1}\expandafter\Threedp\pgfmathresult0000@}
\def\Threedp#1.#2#3#4#5@{#1.#2#3#4}
\begin{document}
\pgfdeclarelayer{blacknotes}
\pgfsetlayers{main,blacknotes}
\tikzset{tight fit/.style={inner sep=0pt, outer sep=0pt}}

\begin{tikzpicture}
\def\lastnotenodename{clefs}
\node [text width=1cm, tight fit] (clefs) at (0,0) {
    \begin{music}
        \instrumentnumber{1}
        \instrumentnumber{2}
        \nostartrule        
        \setstaffs1{1}
        \setstaffs2{1}  
        \setclef1{\bass}
        \setclef2{\treble}                                  
        \startextract
        \hskip2.0\elemskip
        \zendextract
    \end{music}
};

\foreach \note [
    evaluate={
        \n=int(mod(\note-1, 12));
        \octave=int((\note+8)/12);
        \t=int(floor((\note-1)/12)*7-7);
        \notename={"A","","B","C","","D","","E","F","","G",""}[\n];
        \tonicsolfa={"la","","si","so","","r\`e","","mi","fa","","sol",""}[\n];
        \blacknote={0,1,0,0,1,0,1,0,0,1,0,1}[\n];
        \frequency=(2^((\note-49)/12))*440;}
] in {1,...,88}{

    \ifnum\octave>3
        \tikzset{extract anchor/.style={anchor=south west, at=(\lastnotenodename.south east)}}
    \else
        \tikzset{extract anchor/.style={anchor=north west, at=(\lastnotenodename.north east)}}
    \fi
    \ifnum\blacknote=0
        \edef\notenodename{\notename_\octave}
        \node (\notenodename) [tight fit,text width=1cm, extract anchor/.try]  {%           
            \begin{music}
                \instrumentnumber{1}
                \instrumentnumber{2}
                \nostartrule        
                \setstaffs1{1}
                \setstaffs2{1}  
                \setclefsymbol1{\empty}
                \setclefsymbol2{\empty}     
                \setclef1{\bass}
                \setclef2{\treble}                      
                \startextract
                \transpose\t
                \hskip-1.5\elemskip         
                \ifnum\octave>3
                    \ifnum\octave>4
                        \Notes \nextinstrument \ql{\notename} \en       
                    \else
                        \Notes \nextinstrument \qu{\notename} \en                       
                    \fi
                \else
                    \ifnum\octave>2
                        \Notes \ql{\notename} \en
                    \else
                        \Notes \qu{\notename} \en
                    \fi
                \fi
                \zendextract
            \end{music}
        };
        \xdef\lastnotenodename{\notenodename}       
        \node [anchor=base] (sol-fa)  at (\notenodename |- 0,-3) {\tonicsolfa$_\octave$};

        \draw (\notenodename.south west |- 0,-4) rectangle ++(1, -4);
        \node [rotate=90, font=\footnotesize, anchor=east] 
            at (\notenodename.north |- 0,-4) {\threedp\frequency};
        \node [font=\footnotesize, anchor=south]  
            at (\notenodename.south |- 0,-8) {\note};
        \node [font=\footnotesize, anchor=south] 
            at (\notenodename.south |- 0,-8.5)  {\notename$_\octave$};
        \draw (\notenodename.south west |- sol-fa.south) 
            rectangle (\notenodename.south east |- 0,1.125); %0.125 by trial and error
    \else
        \begin{pgfonlayer}{blacknotes}
        \fill ([xshift=-0.25cm]\lastnotenodename.north east |- 0,-4) rectangle ++(0.5, -2.5);
        \node  [rotate=90, text=white, font=\footnotesize, anchor=east]
            at (\lastnotenodename.north east |- 0,-4) {\threedp\frequency};
        \end{pgfonlayer}
    \fi
}
\node [rotate=90] at (0,-6) {Fr\`equency (Hz)};
\end{tikzpicture}

\end{document}

At the moment only one page is printed with a part of the picture:

The code is from Range of a piano: keyboard vs staves .

Answer 1

Using collectbox and trimclip we can realize what you want in a more general way, that is, for any box. I added some optional arguments for additional clipping (e.g. for dealing with content that exceeds its bounding box).

\documentclass{scrbook}

\usepackage{mwe}
\usepackage{trimclip}
\usepackage{xparse}

\makeatletter
  \newcommand\doublepagesplitoverlap{1cm}
  \NewDocumentCommand\doublepagesplit{
    O{\doublepagesplitoverlap}    % overlap
    D||{0pt}  % clip left
    D||{#2}   % clip right
    D!!{0pt}  % clip top
    D!!{#4}   % clip bottom
  }{%
    \cleardoubleevenpage\leavevmode\vfil
    \flushright
    \collectbox{%
      \@doublepagesplit
        {#2}{#4}%
        {\dimexpr (\width - #1) / 2\relax}%
        {#4}{#5}%
    }%
  }
  \newcommand\@doublepagesplit[5]{%
    \clipbox{{#1} {#2} {#3} {#5}}{\BOXCONTENT}%
    \clearpage\leavevmode\vfil
    \flushleft
    \clipbox{{#3} {#2} {#4} {#5}}{\BOXCONTENT}%
    \clearpage
  }
\makeatother

\begin{document}

\doublepagesplit{\includegraphics{example-image}\relax}

\end{document}

Putting this into your document (and copying KOMA-Script's \cleardoubleevenpage) we get

\documentclass{article}

\usepackage[a4paper,margin=.5cm,landscape]{geometry}
\usepackage{tikz}
\usepackage{musixtex}
\usepackage{trimclip}
\usepackage{xparse}

\def\threedp#1{\pgfmathparse{#1}\expandafter\Threedp\pgfmathresult0000@}
\def\Threedp#1.#2#3#4#5@{#1.#2#3#4}

\makeatletter
  \newcommand*\cleardoubleevenpage{%
    \clearpage
    \if@twoside\ifodd\c@page
        \hbox{}\newpage\if@twocolumn\hbox{}\newpage\fi
    \fi\fi
  }
  \newcommand\doublepagesplitoverlap{1cm}
  \NewDocumentCommand\doublepagesplit{
    O{\doublepagesplitoverlap}    % overlap
    D||{0pt}  % clip left
    D||{#2}   % clip right
    D!!{0pt}  % clip top
    D!!{#4}   % clip bottom
  }{%
    \cleardoubleevenpage\leavevmode\vfil
    \flushright
    \collectbox{%
      \@doublepagesplit
        {#2}{#4}%
        {\dimexpr (\width - #1) / 2\relax}%
        {#4}{#5}%
    }%
  }
  \newcommand\@doublepagesplit[5]{%
    \clipbox{{#1} {#2} {#3} {#5}}{\BOXCONTENT}%
    \clearpage\leavevmode\vfil
    \flushleft
    \clipbox{{#3} {#2} {#4} {#5}}{\BOXCONTENT}%
    \clearpage
  }
\makeatother

\pgfdeclarelayer{blacknotes}
\pgfsetlayers{main,blacknotes}
\tikzset{tight fit/.style={inner sep=0pt, outer sep=0pt}}

\begin{document}

\doublepagesplit|-.5cm|{%
\begin{tikzpicture}
\def\lastnotenodename{clefs}
\node [text width=1cm, tight fit] (clefs) at (0,0) {
    \begin{music}
        \instrumentnumber{1}
        \instrumentnumber{2}
        \nostartrule        
        \setstaffs1{1}
        \setstaffs2{1}  
        \setclef1{\bass}
        \setclef2{\treble}                                  
        \startextract
        \hskip2.0\elemskip
        \zendextract
    \end{music}
};

\foreach \note [
    evaluate={
        \n=int(mod(\note-1, 12));
        \octave=int((\note+8)/12);
        \t=int(floor((\note-1)/12)*7-7);
        \notename={"A","","B","C","","D","","E","F","","G",""}[\n];
        \tonicsolfa={"la","","si","so","","r\`e","","mi","fa","","sol",""}[\n];
        \blacknote={0,1,0,0,1,0,1,0,0,1,0,1}[\n];
        \frequency=(2^((\note-49)/12))*440;}
] in {1,...,88}{

    \ifnum\octave>3
        \tikzset{extract anchor/.style={anchor=south west, at=(\lastnotenodename.south east)}}
    \else
        \tikzset{extract anchor/.style={anchor=north west, at=(\lastnotenodename.north east)}}
    \fi
    \ifnum\blacknote=0
        \edef\notenodename{\notename_\octave}
        \node (\notenodename) [tight fit,text width=1cm, extract anchor/.try]  {%           
            \begin{music}
                \instrumentnumber{1}
                \instrumentnumber{2}
                \nostartrule        
                \setstaffs1{1}
                \setstaffs2{1}  
                \setclefsymbol1{\empty}
                \setclefsymbol2{\empty}     
                \setclef1{\bass}
                \setclef2{\treble}                      
                \startextract
                \transpose\t
                \hskip-1.5\elemskip         
                \ifnum\octave>3
                    \ifnum\octave>4
                        \Notes \nextinstrument \ql{\notename} \en       
                    \else
                        \Notes \nextinstrument \qu{\notename} \en                       
                    \fi
                \else
                    \ifnum\octave>2
                        \Notes \ql{\notename} \en
                    \else
                        \Notes \qu{\notename} \en
                    \fi
                \fi
                \zendextract
            \end{music}
        };
        \xdef\lastnotenodename{\notenodename}       
        \node [anchor=base] (sol-fa)  at (\notenodename |- 0,-3) {\tonicsolfa$_\octave$};

        \draw (\notenodename.south west |- 0,-4) rectangle ++(1, -4);
        \node [rotate=90, font=\footnotesize, anchor=east] 
            at (\notenodename.north |- 0,-4) {\threedp\frequency};
        \node [font=\footnotesize, anchor=south]  
            at (\notenodename.south |- 0,-8) {\note};
        \node [font=\footnotesize, anchor=south] 
            at (\notenodename.south |- 0,-8.5)  {\notename$_\octave$};
        \draw (\notenodename.south west |- sol-fa.south) 
            rectangle (\notenodename.south east |- 0,1.125); %0.125 by trial and error
    \else
        \begin{pgfonlayer}{blacknotes}
        \fill ([xshift=-0.25cm]\lastnotenodename.north east |- 0,-4) rectangle ++(0.5, -2.5);
        \node  [rotate=90, text=white, font=\footnotesize, anchor=east]
            at (\lastnotenodename.north east |- 0,-4) {\threedp\frequency};
        \end{pgfonlayer}
    \fi
}
\node [rotate=90] at (0,-6) {Fr\`equency (Hz)};
\end{tikzpicture}
}

\end{document}