How can "execute at begin node" be used with special characters like curly braces? (or: how to raise node content)

Question

I'd like to define the following style:

test/.style={
    execute at begin node={\raisebox\{-0.2cm\}\{},
    execute at end node={\}}
}

and use it like

\documentclass{article} 
\usepackage{tikz}

\tikzset{
    test/.style={
        execute at begin node={\raisebox\{-0.2cm\}\{},
        execute at end node={\}}
    }
}

\begin{document}

    \begin{tikzpicture}
        \node[test,circle,draw] {g};    
    \end{tikzpicture}

\end{document}

But it seems to be wrong, as I get errors like "! Extra }, or forgotten \endgroup" or "Missing number, treated as zero".

I guess the problem is due to the braces. How can I escape them properly?

EDIT: From the answers it became clear that \raisebox alone (like I tried in my broken solution) would've somehow worked in my case (because the dimension was so small that it didn't change the node size (at least I can't see it), which is what I wanted). So I consider all answers correct that only handled this specific/simple case. Answers using \smash and \phantom solved the problem I had actually in mind (but which I didn't clearly formulate as a question). Thanks again for all the great answers! :)

WARNING: As already said by percusse, if one only wants to align the text baselines, don't use this! Instead, as described in the "Putting a Diagram in Chains" tutorial of the manual, use text height and text depth on all nodes to be aligned, e.g. text height=1.5ex,text depth=.25ex.

Answer 1

If I want to do something with the node’s content (which, to my recollection, cannot be accessed by a key), I collect it in a savebox via the lrbox environment.

In the following example, the text is saved in the savebox \qrrTikzNodeContent and then, still in the execute at end node key, used.

Firstly it is typeset in \phantom so that the node gets re-sized appropriately (as if the content would be typeset as usual). The following \usebox command is firstly \llaped to occupy the same horizontal space like its phantom-ed version, and than \smashed so that it doesn’t occupy any vertical space.

I added some hopefully useful keys, that should help how \raisebox may affect the node:

• phantom re-sizes the node as if the content would be typeset in the usual way;
• smash deactivates re-sizing of the node as forced by \raisebox.

This does not work with the keys text width and align as \tikz@atbegin@node is executed after the minipage is applied that is used to realize those keys.

For this special use-case I want to point out that there’s also the text depth key. For <content> without a depth setting this to <value> is like a \raisebox{<value>}{<depth>}.

The following code procudes a matrix of nodes:

  normal        raise            raise + phantom
text depth  raise + smash    raise + phantom + smash

Additionally it shows the baseline of the node.

Code

\documentclass[tikz]{standalone}
\newsavebox\qrrTikzNodeContent
\newif\ifphantom% remove for 'clean' version
\newif\ifsmash  % remove for 'clean' version
\tikzset{
  nodes={draw,circle},
  bl/.style={append after command={\pgfextra{\draw[very thin] (\tikzlastnode.base west) -- (\tikzlastnode.base east);}}},% debug, remove for 'clean' version
  phantom/.is if=phantom,% remove for 'clean' version
  smash/.is if=smash,    % remove for 'clean' version
  raise/.style={
    execute at begin node={\begingroup\begin{lrbox}{\qrrTikzNodeContent}},
    execute at end node={\end{lrbox}% remove for 'clean' version
      \ifphantom
          \phantom{\usebox\qrrTikzNodeContent}%
      \fi
      \ifsmash\smash{\fi
        \ifphantom\llap{\fi
          \raisebox{#1}{\usebox\qrrTikzNodeContent}%
        \ifphantom}\fi
      \ifsmash}\fi
      \endgroup
    },
%    execute at end node={\end{lrbox}% 'clean' version
%      \phantom{\usebox\qrrTikzNodeContent}%
%      \smash{%
%        \llap{%
%          \raisebox{#1}{\usebox\qrrTikzNodeContent}%
%        }%
%      }%
%      \endgroup
%    }
  },
}
\begin{document}
  \begin{tikzpicture}
    \matrix[draw=none, append after command={}, row sep=1ex, column sep=1ex] {
      \node[bl,                            ] {g}; &
      \node[bl, raise=-.2cm,               ] {g}; &  % only raisebox
      \node[bl, raise=-.2cm,        phantom] {g}; \\ % phantom
      \node[bl, text depth=-.2cm           ] {g}; &  % text depth
      \node[bl, raise=-.2cm, smash,        ] {g}; &  % smash
      \node[bl, raise=-.2cm, smash, phantom] {g}; \\ % smash + phantom
    };
  \end{tikzpicture}

  \begin{tikzpicture}
    \matrix[draw=none, append after command={}, row sep=1ex, column sep=1ex] {
      \node[bl,                            ] {h}; &
      \node[bl, raise=-.2cm,               ] {h}; &  % only raisebox
      \node[bl, raise=-.2cm,        phantom] {h}; \\ % phantom
      \node[bl, text depth=-.2cm           ] {h}; &  % text depth
      \node[bl, raise=-.2cm, smash,        ] {h}; &  % smash
      \node[bl, raise=-.2cm, smash, phantom] {h}; \\ % smash + phantom
    };
  \end{tikzpicture}
\end{document}

Output

Answer 2

How about:

\documentclass{standalone} 
\usepackage{tikz}

\newbox\collectbox
\tikzset{
    raise text/.style={
        execute at begin node={\setbox\collectbox=\hbox\bgroup},
        execute at end node={%
            \egroup%
            \phantom{\copy\collectbox}%
            \kern-\wd\collectbox%
            \smash{\raisebox{#1pt}{\box\collectbox}}}
    }
}

\begin{document}

\foreach \y in {-5,-4,...,5}
    \tikz\node [raise text=\y, circle, draw] {g}; 

\end{document}

Obviously the use of \smash means the text isn't taken in to account when calculating the bounding box (which isn't a problem in this case as the text is inside the node path).

EDIT: Actually, I see this is, in essence, identical to the answer given by Qrrbrbirlbel above, only mine is a bit less versatile.

Answer 3

I would strongly recommend not doing this since what you have in mind is valid for matrix cells but not for regular nodes. In fact, for the regular node handling, it's not just grab whatever is provided between{} but more complicated text color,font etc. adjustments take place. You can instead do your adjustments by text height,text depth etc. tools provided or put a label style externally.

But if you want to get a little adventurous then you need to give a little care for your group not to be closed (in this context delimiters matched) too quickly.

\documentclass{article}
\usepackage{tikz}

\tikzset{
    test/.style={
        execute at begin node=\raisebox{#1}\protect\begingroup,
        execute at end node=\endgroup
    }
}

\begin{document}

    \begin{tikzpicture}
        \draw (-5,0) rectangle (5,3);
                \foreach\x in{-10,-9,...,10}{
        \node[circle,draw,test=\x mm] at (4*\x mm,1.5){g};
                }
    \end{tikzpicture}


\end{document}

See how box raise amount is pushing the box in the reverse direction (which is another evidence for why you should not do this.

Answer 4

Perhaps something like this?

\documentclass[tikz,border=2]{standalone} 

\tikzset{test/.style={yshift=-0.15cm}}
\newcommand{\MyNode}[2]{
        \node (#1) at (#2) [test,circle,draw] {\phantom{#1}};    
        \node [test] at (#1) {#1};
}
\begin{document}
    \begin{tikzpicture}
        \MyNode{g}{0,0}
        \MyNode{h}{1,0}
    \end{tikzpicture}
\end{document}

Answer 5

If you simply want to raise the node content you can use

\tikzset{test/.style={yshift=-0.2cm}}

As mentioned in the comments, the problem is not with escaping the curly braces, but rather with code fragments.

Answer 6

OK, first of all I don't think that a key execute at begin node actually exists in TikZ. There is however execute at begin scope, maybe you want to use that.

Now about the escaping of braces: You don't have to use braces around the code for execute at.... Instead just put your code on one line and use \bgroup and \egroup:

test./style={
    execute at begin scope=\bgroup\raisebox{-0.2cm}
    execute at end scope=\egroup
}

I'm not sure what exactly you are trying to achieve with this code, so my answer may not be exactly what you were looking for.