[Tex/LaTex] Center a Node Vertically TikZ

nodespositioningtikz-pgf

I'm using TikZ to create the following drawing:

drawing

So far so good, but now I'd like to center the node with the gray background vertically. Here's its code:

\setlength{\arraycolsep}{2pt}
\draw[xshift=-3cm,yshift=(current bound box.center)]
  node[align=left,right,rounded corners,fill=black!10,inner sep=1ex]
  {$
    \left\{
      \begin{array}{llc}
        h &=& \overline{AF}\\
        l &=& \overline{BF}\\
        l'&=& \overline{AB}\\
        d &=& \overline{CE}
      \end{array}
    \right.
  $};

It's being pushed to the left by xshift, thus I could equally use yshift with a measure to center it. However, is it possible to do it dynamically (by retrieving the bounding box height)? That's, if the drawing grows, it will remain centered.

Best Answer

You could use the positioning library and then use the left=of <node identifier> for positioning the node containing the array; I added some more files to the array to see the effect:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{positioning}

\begin{document}

\begin{tikzpicture}
\setlength{\arraycolsep}{2pt}
\node[draw,fill,circle,inner sep=1pt,label=right:$C$] at (3,0) (c) {};
\node[align=left,rounded corners,fill=black!10,inner sep=1ex,left=of c]
  {$
    \left\{
      \begin{array}{llc}
        h &=& \overline{AF}\\
        l &=& \overline{BF}\\
        l'&=& \overline{AB}\\
        d &=& \overline{CE}\\
        h &=& \overline{AF}\\
        l &=& \overline{BF}\\
        h &=& \overline{AF}\\
        l &=& \overline{BF}\\
      \end{array}
    \right.
  $};
\end{tikzpicture}

\end{document}

enter image description here

More generally (as Caramdir has suggested), you can use left=of current bounding box.center:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{positioning}

\begin{document}

\begin{tikzpicture}
\setlength{\arraycolsep}{2pt}
\node[draw,fill,circle,inner sep=1pt,label=right:$C$] at (3,0) (c) {};
\node[align=left,rounded corners,fill=black!10,inner sep=1ex,left=of current bounding box.center]
  {$
    \left\{
      \begin{array}{llc}
        h &=& \overline{AF}\\
        l &=& \overline{BF}\\
        l'&=& \overline{AB}\\
        d &=& \overline{CE}\\
        h &=& \overline{AF}\\
        l &=& \overline{BF}\\
        h &=& \overline{AF}\\
        l &=& \overline{BF}\\
      \end{array}
    \right.
  $};
\end{tikzpicture}

\end{document}

Related Solutions

[Tex/LaTex] Vertically center a node with the current line in TikZ

Add baseline=(current bounding box.center) as option to the tikzpicture and \tikz command. This places the baseline of the diagrams at its center and will cause a vertical alignment with the other baselines(!).

However, if you want to align it with the vertical center of the text, i.e. the center of "is", which looks most likely better, use
baseline={([yshift=-1ex]current bounding box.center)} instead. Adjust the value for your liking. Maybe .8ex might be better (an uppercase letter is about 1.6ex).

\documentclass{article}

\usepackage{tikz}

\begin{document}

  This is a
  \begin{tikzpicture}[baseline={([yshift=-.8ex]current bounding box.center)}]
    \node[draw, rectangle, align=left] {%
      And here \\[.3em]
      is
      \tikz [baseline={([yshift=-.8ex]current bounding box.center)}]
        \node[draw, rectangle, align=center] {a \\ nested};
    };
  \end{tikzpicture}
  one.
\end{document}

Result

Some other hints:

In general you can use \raisebox{<length>}{<content>} to raise or lower some material. You can use then \height, \depth, \width and \totalheight to refer to the original dimensions of the content. Use \dimexpr to do math:

\raisebox{\dimexpr-.5\height+.5\depth+.8ex\relax}{<content>}

There is also \vcenter{...} which will center things vertical, but it is intended to be used in mathmode.

[Tex/LaTex] tikz center node below 2 other nodes

Firstly, I'm not sure of what you want. I understand that you want the last node "bot" in the middle of (node1node2) and (node4node3) but before I would like to know if you want a symmetric graph.

In this case you need to write \node (node4node3) [below left of=node4] instead of \node (node4node3) [below right of=node3].

If the graph is symmetric then the middle is below (top) and there is no problem to place (bot).

If the graph is not symmetric first you can use Peter's method with the libraries calc and positioning but I think you need to avoid the old way to place the nodes. Explanation : Instead of below left of=top you need to write below left= of top.

/tikz/above left (no value) Does the same as anchor=south east. Note that giving both above and left options does not have the same effect as above left, rather only the last left “wins.” Actually, this option also takes an ⟨offset⟩ parameter, but using this parameter without using the positioning library is deprecated. (The positioning library changes the meaning of this parameter to something more sensible.)

The result is not the same because the node distance is not the distance between the centers of the nodes. If you want the same result, you need to use the option on grid.

To get the middle of two nodes, you can avoid the library calc with

  \path (A) -- node [below= 3cm] {$\bot$} (B);

My solution

\documentclass[11pt]{scrartcl}
\usepackage{tikz}
\usetikzlibrary{positioning}

\begin{document}


\begin{center}
 \begin{tikzpicture}[node distance=3cm,on grid]
       \draw[help lines] (-6,-9) grid (6,1);
  \node (top)          {$\top$};
  \node (node1)      [below left=  of top]             {\{node1\}};
  \node (node2)      [left=        of node1]           {\{node2\}};
  \node (node3)      [below right= of top]             {\{node3\}};
  \node (node4)      [right=       of node3]           {\{node4\}};
  \node (node1node2) [below right= of node2]           {\{node2 , node1\}};
  \node (node4node3) [below right= of node3]           {\{node3, node4\}};
  \path (node1node2) -- node (bot) [text=red,below=3cm] {$\bot$} (node4node3);
  \draw (top)         edge (node1)
                      edge (node2)
                      edge (node3)
                      edge (node4);
  \draw (node1node2)  edge (bot)
                      edge (node1) 
                      edge (node2);
  \draw (node4node3)  edge (bot)
                      edge (node3) 
                      edge (node4);                    

 \end{tikzpicture}
 \end{center}
\end{document}

enter image description here

With the next code the graph is symmetric

\begin{center}
 \begin{tikzpicture}[node distance=3cm,on grid]
    ...
  \node (node4node3) [below left=  of node4]           {\{node3, node4\}};
   ...                    
 \end{tikzpicture}
 \end{center}

enter image description here

without 'on gridand with the defaultnode distance`

\documentclass[11pt]{scrartcl}
\usepackage{tikz}
\usetikzlibrary{positioning}

\begin{document}
 \begin{center}
  \begin{tikzpicture}
        \draw[help lines] (-6,-9) grid (6,1);
   \node (top)          {$\top$};
   \node (node1)      [below left=  of top]             {\{node1\}};
   \node (node2)      [left=        of node1]           {\{node2\}};
   \node (node3)      [below right= of top]             {\{node3\}};
   \node (node4)      [right=       of node3]           {\{node4\}};
   \node (node1node2) [below right= of node2]           {\{node2 , node1\}};
   \node (node4node3) [below right= of node3]           {\{node3, node4\}};
   \path (node1node2) -- node (bot) [text=red,below=1cm] {$\bot$} (node4node3);
   \draw (top)         edge (node1)
                       edge (node2)
                       edge (node3)
                       edge (node4);
   \draw (node1node2)  edge (bot)
                       edge (node1) 
                       edge (node2);
   \draw (node4node3)  edge (bot)
                       edge (node3) 
                       edge (node4);                    

  \end{tikzpicture}
  \end{center}
\end{document}

enter image description here

Remarks, complements

To place a node between two others nodes there is two methods :

1)   \begin{tikzpicture}
     \node  (a) {a}  ;             
     \node  (b) at (4,2) {b};
     \path   (a) -- node {m} (b);
      %  or \path (a) -- (b) node[midway]{m}; 
      % or pos =.5  instead of midway
  \end{tikzpicture}

2)    \begin{tikzpicture} % with calc library
       \node  (a) {a}  ;             
       \node  (b) at (4,2) {b};
       \node   at ($(a)!0.5!(b)$) {m};
       \end{tikzpicture}

The choice of the method depends of the way used to create the graphs ( with absolute coordinates, with the positioning library or without, with the possibility to scale , if you need to add several nodes)

  \begin{tikzpicture}
     \node  (a) {a}  ;             
     \node  (b) at (8,0) {b};
      \path (a) -- (b) node[pos=.25]{c} node[pos=.5]{d} node[pos=.75]{e}; 
  \end{tikzpicture}

If you need to place a node below the middle. It's interesting to use the positioning library except if you need to scale the picture.

Without the positioning library, 5 signifies 5 pt in \path (a) -- node[below=5] {m} (b); but with the positioning library 5 signifies 5 cm

If you need to scale the picture, it's interesting to use the calc library and to avoid positioning. Example :

 \node at ($(a)!0.5!(b)+(0,-1)$) {m};

With this method, you can use scale=2

Best Answer

Related Solutions

[Tex/LaTex] Vertically center a node with the current line in TikZ

[Tex/LaTex] tikz center node below 2 other nodes

Related Question