Every non-label node in TikZ

Question

In TikZ we can use every node/.style=... and every label/.style=... but is there a way to say something like every non label/.style=... so that I can define styles for non-label and label nodes without interference?

Answer 1

Tricky. The key every node is tried on every node. The key every label is called after the every node so it is possible to undo anything that every node does in the every label, but then you'd have to remember exactly what was set and know how to undo it.

Here's one way to achieve this. It works by using the fact that labels are always subordinate to nodes, and that (so far as I'm aware), no other nodes are subordinate to them (this might be a bit funny with matrices or chains - not tested). So we want a key, say every non label, which is executed on the parent node but not on any children (labels). One way to do that is for the key every non label to clear itself upon being executed. That ensures that it doesn't propagate downwards. As we do this in a group (the node group), this clearing only affects children and not siblings (ie other proper nodes), even on the same path.

Depending on exactly what you were doing, it might be necessary to be a bit careful with how this interacts with other keys. For example, if you put a label key in an every node one then you have to ensure that the blanking key occurs first.

\documentclass{article}
%\url{http://tex.stackexchange.com/q/49096/86}
\usepackage{tikz}
\usetikzlibrary{shadows}

\tikzset{
  clear label/.style={
    append after command={
      [every non label/.style={}]
    }
  },
  every node/.style={
    every non label,
    clear label
  },
  every non label/.style={
    circular drop shadow,
  }
}

\begin{document}
\begin{tikzpicture}
\node[label=hello] {world};
\node[label=hello] at (0,-2) {world};
\path (0,-4)  node[label=hello] {world} (1,-4) node[label=hello] {world};
\end{tikzpicture}
\end{document}

Result:

Answer 2

No tricky no hackish solution because I think it's bad problem. It's a bad use of every node.

This situation appears in some tutorials of the pgfmanual. First Andrew makes this remark : The key every label is called after the every node and It's necessary to complete with a text from the pgfmanual :

/tikz/label=[⟨options⟩]⟨angle⟩:⟨text⟩ (no default) When this option is given to a node operation, it causes another node to be added to the path after the current node has been finished. This extra node will have the text ⟨text⟩.

In other terms, the label is another node, so it's normal that you get some interferences.

What you need to do ? You can work with a ticky or hackish method or you can avoid the problem with a more natural code.

I tink the better way is to define a style not for every node but for a specific node

\documentclass[11pt]{scrartcl}
\usepackage{tikz}
\usetikzlibrary{shadows}
\begin{document} 

 \begin{tikzpicture} [every node/.style = {circle},
                      every special node/.style = {},
                      special node/.style={draw = blue!50,
                                           fill = blue!20,
                                           thick,
                                           every special node}]

\tikzset{every special node/.style={circular drop shadow=red!20}} 
\tikzset{every label/.style={red}}  % by default draw=none  except if every node uses "draw"

 \node[special node,label={0:A}] {B}; 
 \end{tikzpicture}
\end{document}  

Answer 3

Another hackish solution for this particular example is to remove the shadow by emptying the preaction key. This is something I learned from this question.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shadows,shapes.geometric}
\makeatletter
\tikzset{every node/.style ={draw,shape=ellipse,circular drop shadow,blue},
every label/.style={yellow,draw=none,fill=red,shape=trapezium,fill opacity=0.5},
every label/.add code={}{\let\tikz@preactions\pgfutil@empty}
} 
\makeatother
\begin{document}
\begin{tikzpicture} 
\node[label={0:Trapezium}] {Ellipse}; 
\end{tikzpicture} 
\end{document}

Since the regular options can be overridden, I guess that, only pre- and post- actions remain persistent and as seen from this simple example we simply squeeze in an innocent "You know what, forget about what I said earlier about the preactions" line. Seemingly it does the job. You can add also a line for the postactions too. Still, I can imagine that there might be some persistent options left out.