mjhjmtu

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]%
 IfInTikzPictikzpicture[remember picture]
 draw[ultra thick, ->, #1] (0,) -- (1,1) node [right] output of DrawLine;
 IfInTikzPicendtikzpicture%

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:

documentclassarticle
usepackagetikz

makeatletter
newcommandIfInTikzPic[2]% https://tex.stackexchange.com/a/121309/4301
 ifxpgfpictureid@undefined#2else#1fi%

makeatother

newcommand*DrawLine[1]%
 IfInTikzPictikzpicture[remember picture]
 draw[ultra thick, ->, #1] (0,) -- (1,1) node [right] output of DrawLine;
 IfInTikzPicendtikzpicture%


begindocument
%%% The commented out code here is to show that IfInTikzPic works as desired
%%% (in a tikzpicture, outside of a node).
%%%

%textbfIfInTikzPicpar
%IfInTikzPicinsideoutside
%
%begintikzpicture
% IfInTikzPicdraw [red, ultra thick]draw [blue, ultra thick] (0,0) -- (1,0);
%endtikzpicture
%
%medskip% --------------------------
textbfDrawLine: Actual Outputpar

%DrawLineblue% <---- How do I get this case to work?

begintikzpicture
 DrawLineorange
endtikzpicture

medskip% --------------------------
textbfDrawLine: Desired Outputpar

begintikzpicture
 DrawLineblue
endtikzpicture

begintikzpicture
 DrawLineorange
endtikzpicture
enddocument

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

documentclassarticle

usepackagetikz

makeatletter
def@tikzenvironmenttikzpicture

newcommandIfInTikzPic%
 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

begindocument

textbfDrawLine: Actual Outputpar

DrawLineblue

begintikzpicture
 DrawLineorange
endtikzpicture

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

textbfDrawLine: Desired Outputpar

begintikzpicture
 DrawLineblue
endtikzpicture

begintikzpicture
 DrawLineorange
endtikzpicture

enddocument

You could also group the tikzpicture if needed:

newcommandIfInTikzPic%
 edeftikzstart%
 ifx@currenvir@tikzenvironmentelse
 noexpandbegintikzpicture[remember picture]%
 fi
 %
 edeftikzend%
 ifx@currenvir@tikzenvironmentelse
 noexpandendtikzpicture%
 fi
 %

documentclassarticle
usepackagetikz

makeatletter
newcommandIfInTikzPic% https://tex.stackexchange.com/a/121309/4301
 ifxpgfpictureid@undefined
 expandafter@firstoftwo
 else
 expandafter@secondoftwo
 fi

makeatother

newcommand*DrawLine[1]%
 IfInTikzPic
 begintikzpicture[remember picture]
 draw[ultra thick, ->, #1] (0,) -- (1,1) node [right] output of DrawLine;
 endtikzpicture%
 draw[ultra thick, ->, #1] (0,) -- (1,1) node [right] output of DrawLine;%


begindocument
%%% The commented out code here is to show that IfInTikzPic works as desired
%%% (in a tikzpicture, outside of a node).
%%%

textbfIfInTikzPicpar
IfInTikzPicinsideoutside

begintikzpicture
 IfInTikzPicdraw [red, ultra thick]draw [blue, ultra thick] (0,0) -- (1,0);
endtikzpicture

medskip% --------------------------
textbfDrawLine: Actual Outputpar

DrawLineblue% <---- How do I get this case to work?

begintikzpicture
 DrawLineorange
endtikzpicture

medskip% --------------------------
textbfDrawLine: Desired Outputpar

begintikzpicture
 DrawLineblue
endtikzpicture

begintikzpicture
 DrawLineorange
endtikzpicture
enddocument

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

documentclassarticle
usepackagetikz

makeatletter
newcommandensuretikz% https://tex.stackexchange.com/a/121309/4301
 ifxpgfpictureid@undefined
 expandaftertikzify
 else
 expandafter@firstofone
 fi

makeatother

deftikzify#1begintikzpicture#1endtikzpicture

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


begindocument
%%% The commented out code here is to show that IfInTikzPic works as desired
%%% (in a tikzpicture, outside of a node).
%%%




medskip% --------------------------
textbfDrawLine: Actual Outputpar

DrawLineblue% <---- How do I get this case to work?

begintikzpicture
 DrawLineorange
endtikzpicture

medskip% --------------------------
textbfDrawLine: Desired Outputpar

begintikzpicture
 DrawLineblue
endtikzpicture

begintikzpicture
 DrawLineorange
endtikzpicture
enddocument