Xtykutl

I would like to define the DrawLine macro below so that it can be invoked from within a {tikzpicture} environment or from outside:

newcommand*{DrawLine}[1]{%

  IfInTikzPic{}{tikzpicture[remember picture]}

      draw[ultra thick, ->, #1] (0,) -- (1,1) node [right] {output of DrawLine};

  IfInTikzPic{}{endtikzpicture}%

}

This works fine when invoked from within a {tikzpicture}, but not when it is invoked from outside (line is commented in the MWE). Invoking it from outside yields the error:

Missing endgroup inserted.

The MWE below uses the first reference below. The other two references also fail on the commented out test case.

References:

• Detecting if inside a tikzpicture node. Even though this solution is for detecting within a node, it appears to work to detect if you are within a tikzpicture (as the commented out code in the MWE shows).




• Is there a (simple) way to find out if a command is executed in a tikzpicture environment?.




• How can I check if the current code is inside a certain environment?.

Code:

documentclass{article}

usepackage{tikz}



makeatletter

newcommand{IfInTikzPic}[2]{% https://tex.stackexchange.com/a/121309/4301

  ifxpgfpictureid@undefined#2else#1fi%

}

makeatother



newcommand*{DrawLine}[1]{%

  IfInTikzPic{}{tikzpicture[remember picture]}

      draw[ultra thick, ->, #1] (0,) -- (1,1) node [right] {output of DrawLine};

  IfInTikzPic{}{endtikzpicture}%

}



begin{document}

%%% The commented out code here is to show that IfInTikzPic works as desired

%%% (in a tikzpicture, outside of a node).

%%%



%textbf{IfInTikzPic}par

%IfInTikzPic{inside}{outside}

%

%begin{tikzpicture}

%  IfInTikzPic{draw [red, ultra thick]}{draw [blue, ultra thick]} (0,0) -- (1,0);

%end{tikzpicture}

%

%medskip% --------------------------

textbf{DrawLine}: Actual Outputpar



%DrawLine{blue}% <---- How do I get this case to work?



begin{tikzpicture}

  DrawLine{orange}

end{tikzpicture}



medskip% --------------------------

textbf{DrawLine}: Desired Outputpar



begin{tikzpicture}

  DrawLine{blue}

end{tikzpicture}



begin{tikzpicture}

  DrawLine{orange}

end{tikzpicture}

end{document}

The following example defines IfInTikzPic to check the current environment against tikzpicture and define a tikzstart...tikzend pair accordingly:

documentclass{article}



usepackage{tikz}



makeatletter

def@tikzenvironment{tikzpicture}



newcommand{IfInTikzPic}{%

  edeftikzstart{%

    ifx@currenvir@tikzenvironmentelse

      noexpandtikzpicture[remember picture]%

    fi

  }%

  edeftikzend{%

    ifx@currenvir@tikzenvironmentelse

      noexpandendtikzpicture%

    fi

  }%

}



newcommand*{DrawLine}[1]{%

  IfInTikzPic

  tikzstart

    draw[ultra thick, ->, #1] (0,) -- (1,1) node [right] {output of DrawLine};

  tikzend%

}

makeatother



begin{document}



textbf{DrawLine}: Actual Outputpar



DrawLine{blue}



begin{tikzpicture}

  DrawLine{orange}

end{tikzpicture}



medskip% --------------------------



textbf{DrawLine}: Desired Outputpar



begin{tikzpicture}

  DrawLine{blue}

end{tikzpicture}



begin{tikzpicture}

  DrawLine{orange}

end{tikzpicture}



end{document}

You could also group the tikzpicture if needed:

newcommand{IfInTikzPic}{%

  edeftikzstart{%

    ifx@currenvir@tikzenvironmentelse

      noexpandbegin{tikzpicture}[remember picture]%

    fi

  }%

  edeftikzend{%

    ifx@currenvir@tikzenvironmentelse

      noexpandend{tikzpicture}%

    fi

  }%

}

documentclass{article}

usepackage{tikz}



makeatletter

newcommand{IfInTikzPic}{% https://tex.stackexchange.com/a/121309/4301

  ifxpgfpictureid@undefined

    expandafter@firstoftwo

     else

    expandafter@secondoftwo

    fi

}

makeatother



newcommand*{DrawLine}[1]{%

  IfInTikzPic

   {begin{tikzpicture}[remember picture]

    draw[ultra thick, ->, #1] (0,) -- (1,1) node [right] {output of DrawLine};

   end{tikzpicture}}%

    {draw[ultra thick, ->, #1] (0,) -- (1,1) node [right] {output of DrawLine};}%

}



begin{document}

%%% The commented out code here is to show that IfInTikzPic works as desired

%%% (in a tikzpicture, outside of a node).

%%%



textbf{IfInTikzPic}par

IfInTikzPic{inside}{outside}



begin{tikzpicture}

  IfInTikzPic{draw [red, ultra thick]}{draw [blue, ultra thick]} (0,0) -- (1,0);

end{tikzpicture}



medskip% --------------------------

textbf{DrawLine}: Actual Outputpar



DrawLine{blue}% <---- How do I get this case to work?



begin{tikzpicture}

  DrawLine{orange}

end{tikzpicture}



medskip% --------------------------

textbf{DrawLine}: Desired Outputpar



begin{tikzpicture}

  DrawLine{blue}

end{tikzpicture}



begin{tikzpicture}

  DrawLine{orange}

end{tikzpicture}

end{document}

Or this version which directly forces tikz rather than having an if-then-else construct

documentclass{article}

usepackage{tikz}



makeatletter

newcommand{ensuretikz}{% https://tex.stackexchange.com/a/121309/4301

  ifxpgfpictureid@undefined

    expandaftertikzify

     else

    expandafter@firstofone

    fi

}

makeatother



deftikzify#1{begin{tikzpicture}#1end{tikzpicture}}



newcommand*{DrawLine}[1]{%

    ensuretikz

    {draw[ultra thick, ->, #1] (0,) -- (1,1) node [right] {output of DrawLine};}%

}



begin{document}

%%% The commented out code here is to show that IfInTikzPic works as desired

%%% (in a tikzpicture, outside of a node).

%%%









medskip% --------------------------

textbf{DrawLine}: Actual Outputpar



DrawLine{blue}% <---- How do I get this case to work?



begin{tikzpicture}

  DrawLine{orange}

end{tikzpicture}



medskip% --------------------------

textbf{DrawLine}: Desired Outputpar



begin{tikzpicture}

  DrawLine{blue}

end{tikzpicture}



begin{tikzpicture}

  DrawLine{orange}

end{tikzpicture}

end{document}