[Tex/LaTex] How to you position a node relatively to another in TikZ

nodespositioningtikz-pgf

I would like to place a node 'B' 60 degrees of an arbitrary node 'A' between which there is a distance of 2cm. I can do this if node 'A' is at (0, 0), so 'B' would just be (60 : 2) from 'A', but what happens when 'A' is not at (0, 0)?

Best Answer

There are multiple ways to do this. Some of them need the calc or positioning TikZ libraries (\usetikzlibrary{calc,positioning}).

The simplest way would be (using calc TikZ-library):

\node (A) at (2,4) {<content>};
\node (B) at ($ (A) + (60:2) $) {<content>};

You can also use the coordinate options ([<options>]<coordinate>) to add a shift option, which doesn't require any libraries but looks a little funny.

\node (B) at ([shift={(60:2)}]A) {<content>};

Related Solutions

How to Position Nodes Around Another Node in TikZ

You may want to use the trees library in tikz, which in this situation would provide, up to me, a rather easy syntax. I made a small example for you.

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{positioning,trees,arrows}


\begin{document}

\begin{tikzpicture}[->,>=stealth',shorten <=0.5pt,
    main/.style={draw,thick,rounded corners, top color=blue!20, bottom color=white,
        minimum width=1cm},
    child/.style={draw,thick,rounded corners, top color=red!20, bottom color=white}]

    \tikzstyle{level 1}=[sibling angle=22.5]

    \node[main] (a) {A} [counterclockwise from=0]
        child { node[child] {1}}
        child { node[child] {2}}
        child { node[child] {3}}
        child { node[child] {4}}
        child { node[child] {5}}
        child { node[child] {6}}
        child { node[child] {7}}
        child { node[child] {8}}
        child { node[child] {9}}
    ;

    \node[main] (ba) [below of=a] {belowA};

    \path 
    (ba) edge (a)
    ;

\end{tikzpicture}

\end{document}

Which gives as result:

enter image description here

[Tex/LaTex] calculate the difference between two relatively positioned nodes with TikZ using calc

If all you want to do is to horizontally align the (bang1) and (bang2) nodes, you don't need such complicated calculations. You can use the let syntax to get the x-coordinate of (bang1) and the y-coordinate of (sub3), using something like

\path let \p1=(bang1), \p2=(sub3) in
node[bangnode,yshift=-2cm,anchor=north] (bang2) at (\x1,\y2) {Bang};

A complete example:

\documentclass[12pt]{standalone}
\usepackage{fontspec}
\usepackage{tikz}
\usetikzlibrary{arrows,positioning,shapes,backgrounds,fit,calc} 

\begin{document}

\begin{tikzpicture}[node distance=3cm, auto]  
\tikzset{
    mynode/.style={rectangle,rounded corners,draw=black, top color=white, bottom color=red!50,very thick, inner sep=1em, minimum size=3em, text centered},
    keynode/.style={rectangle,rounded corners,draw=black, top color=white, bottom color=orange!50,very thick, inner sep=1em, minimum size=3em, text centered},
    bangnode/.style={shape=star, star points=20, star point ratio=1.65,draw=black, top color=white, bottom color=yellow!50,very thick, inner sep=2em, minimum size=3em, text centered,font=\bfseries},
    myarrow/.style={->, >=latex', shorten >=1pt, thick},
    mylabel/.style={text width=7em, text centered} 
}  



\node[bangnode](bang1){Bang};
   \node[keynode,below left=2cm and 2cm of bang1](key){Key Message};
      \node[mynode,below right of=key](sub1){Sub Topic 1};
      \node[mynode,below of=sub1](sub2){Sub Topic 2};
      \node[mynode,below of=sub2](sub3){Sub Topic 3};
\path let \p1=(bang1), \p2=(sub3) in
node[bangnode,yshift=-2cm,anchor=north] (bang2) at (\x1,\y2) {Bang};
%ARROWS
\draw[<->,bend left=45] (sub1)[]to(sub2);
\draw[<->,bend left=45] (sub2)to(sub3);
\draw[<->,bend left=45] (sub1)to (key);
\draw[<->,bend left=45] (sub2)to (key);
\draw[<->,bend left=45] (sub3)to (key);


\begin{pgfonlayer}{background}
    \node [fill=blue!10,fit=(bang1) (bang2) (sub1)(sub2)(sub3)(key)] {};
  \end{pgfonlayer}
\end{tikzpicture}

\end{document}

enter image description here

Another simpler option would be to use the perpendicular coordinate system, and use something like

\node[bangnode,yshift=-2cm,anchor=north] (bang2) at (bang1|-sub3) {Bang};

to place the node using the x-coordinate of (bang1) and the y-coordinate of (sub3). A complete example:

\documentclass[12pt]{standalone}
\usepackage{fontspec}
\usepackage{tikz}
\usetikzlibrary{arrows,positioning,shapes,backgrounds,fit,calc} 

\begin{document}

\begin{tikzpicture}[node distance=3cm, auto]  
\tikzset{
    mynode/.style={rectangle,rounded corners,draw=black, top color=white, bottom color=red!50,very thick, inner sep=1em, minimum size=3em, text centered},
    keynode/.style={rectangle,rounded corners,draw=black, top color=white, bottom color=orange!50,very thick, inner sep=1em, minimum size=3em, text centered},
    bangnode/.style={shape=star, star points=20, star point ratio=1.65,draw=black, top color=white, bottom color=yellow!50,very thick, inner sep=2em, minimum size=3em, text centered,font=\bfseries},
    myarrow/.style={->, >=latex', shorten >=1pt, thick},
    mylabel/.style={text width=7em, text centered} 
}  



\node[bangnode](bang1){Bang};
   \node[keynode,below left=2cm and 2cm of bang1](key){Key Message};
      \node[mynode,below right of=key](sub1){Sub Topic 1};
      \node[mynode,below of=sub1](sub2){Sub Topic 2};
      \node[mynode,below of=sub2](sub3){Sub Topic 3};
\node[bangnode,yshift=-2cm,anchor=north] (bang2) at (bang1|-sub3) {Bang};
%ARROWS
\draw[<->,bend left=45] (sub1)[]to(sub2);
\draw[<->,bend left=45] (sub2)to(sub3);
\draw[<->,bend left=45] (sub1)to (key);
\draw[<->,bend left=45] (sub2)to (key);
\draw[<->,bend left=45] (sub3)to (key);


\begin{pgfonlayer}{background}
    \node [fill=blue!10,fit=(bang1) (bang2) (sub1)(sub2)(sub3)(key)] {};
  \end{pgfonlayer}
\end{tikzpicture}

\end{document}

And, to answer the specific question, of course you can calculate distances between nodes, using veclen and the let syntax; a simple example:

\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{positioning,calc} 

\begin{document}

\begin{tikzpicture}
\node (A) {A};
\node[below left=of A ] (B) {B};
\node[below =of B ] (C) {C};
\node[below right =of C ] (D) {D};
\draw (B) -- (D);
\draw (B) let \p1 = ($ (D) - (B) $)
  in circle ({veclen(\x1,\y1)});
\end{tikzpicture}

\end{document}

enter image description here

In the original code:

\draw (key) let 
  \p1 = ($ (sub3) - (key) $);
  in
  circle ({veclen(\x1,\y1)});

there's a superfluous semicolon at the end of the second line; once this is removed:

\draw (key) let 
  \p1 = ($ (sub3) - (key) $)
  in
  circle ({veclen(\x1,\y1)});

the code should work.

Best Answer

Related Solutions

How to Position Nodes Around Another Node in TikZ

[Tex/LaTex] calculate the difference between two relatively positioned nodes with TikZ using calc

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