[Tex/LaTex] Draw randomized tree in TikZ

nodesrandom numberstikz-pgftikz-treestrees

I am trying to draw a randomized tree using TikZ, that is, I'm looking for a macro \randtree{NN}{x} that attaches a randomized tree of maximum depth x to a node named NN. The nodes need not be visible or marked, I just want the lines.

I did a bit of research on randomized TikZ pictures, but since I never really used randomization with TikZ before, most of the examples were so complicated that I didn't understand what was going on (e.g. Referring to tikz picture again in the same document)
plus, most randomization examples (at least the ones I found) just randomize the shape of individual lines, wheras I want entire node structures to be randomized.
Here is a (non-random, non-automatic) example of what I'm hoping for:

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{positioning}

\newcommand\mytree[1]{
\coordinate[above right=1cm and 1.0cm of #1] (r);
\coordinate[above right=2cm and 2.0cm of r] (rr);
\coordinate[above left =1cm and 0.5cm of r] (rl);
\coordinate[above right=1cm and 1.0cm of rl] (rlr);
\coordinate[above left =1cm and 0.5cm of rl] (rll);
\coordinate[above left =1cm and 1.0cm of #1] (l);
\coordinate[above left =1cm and 1.0cm of l] (ll);
\coordinate[above right=2cm and 0.5cm of l] (lr);
\coordinate[above left =1cm and 1.0cm of lr] (lrl);
\coordinate[above right=1cm and 0.2cm of lr] (lrr);
\coordinate[above left =1cm and 1.0cm of ll] (lll);
\coordinate[above right=1cm and 0.5cm of ll] (llr);
\coordinate[above left =1cm and 1.0cm of rlr] (rlrl);
\draw[black] (lll) -- (ll);
\draw[black] (ll) -- (l);
\draw[black] (l) -- (sv);
\draw[black] (sv) -- (r);
\draw[black] (r) -- (rr);
\draw[black] (r) -- (rl);
\draw[black] (l) -- (lr);
\draw[black] (rl) -- (rll);
\draw[black] (rl) -- (rlr);
\draw[black] (ll) -- (llr);
}

\begin{document}

\begin{tikzpicture}[node distance=1cm and 0.4cm]
\coordinate (sv);
\mytree{sv};
\end{tikzpicture}

\end{document}

It's not required that all branches have the same total height at the end, nor is the absolute number of nodes of any interest. I just want to specify the maximum number of nodes from trunk to leaf, and the total scale of the tree (approximate height and width, both values are allowed to float up or down).
The tree should alway grow from bottom to top, but if that's also customizable, even the better.

A ready-made solution would be too much to ask, so I'll be happy with a simple example or pointers to the appropriate sections of the TikZ manual.

Edit

Following a request from one of the comments, I try to be more clear about what I'm trying to achieve. I'm trying to reproduce the following graphic:
Illustration of event structure simulated by a showering and hadronization generator.

I managed to make most of it on my own, the only thing still missing is the (more-or-less) random decay diagrams on top of the pink blobs (circled in red). Since the precise structure of these things is not of particular importance, nor is the fact that they have arrow tips at their end, I thought that the easiest way to generate them was to create a randomized tree of given size and attach it to the TikZ nodes at the pink blobs.

In the meantime, I opened another question on the same subject, trying to build these decay-chain-structures manually (Drawing recursive randomized structures with TikZ). If you have a solution on how to do this using a tree construct (forest, tikz-qtree, …), please answer to this question – if you know a way how to manually create these structures, please anwer the one linked above.

Edit 2

Since I got a nice answer and was able to plug everything together, I figured I might as well make the source code of my picture available to everyone. Enjoy!

Preparation

\usetikzlibrary{positioning,arrows,patterns}
\usetikzlibrary{decorations.pathmorphing}
\usetikzlibrary{decorations.markings}
\usetikzlibrary{decorations.shapes}

\def\pgfdecoratedcontourdistance{0pt}

\pgfkeys{/pgf/decoration/contour distance/.code={%
    \pgfmathparse{#1}%
    \let\pgfdecoratedcontourdistance=\pgfmathresult}%
}

\pgfdeclaredecoration{contour lineto}{start}
{
    \state{start}[next state=draw, width=0pt]{
        \pgfpathmoveto{\pgfpoint{0pt}{\pgfdecoratedcontourdistance}}%
    }
    \state{draw}[next state=draw, width=\pgfdecoratedinputsegmentlength]{       
        \pgfmathparse{-\pgfdecoratedcontourdistance*cot(-\pgfdecoratedangletonextinputsegment/2+90)}%
        \let\shorten=\pgfmathresult%
        \pgfpathlineto{\pgfpoint{\pgfdecoratedinputsegmentlength+\shorten}{\pgfdecoratedcontourdistance}}%  
    }
    \state{final}{
        \pgfpathlineto{\pgfpoint{\pgfdecoratedinputsegmentlength}{\pgfdecoratedcontourdistance}}%
    }   
}

\tikzset{
  photon/.style={decorate, decoration={snake}, draw=black},
  crossed/.style={draw=black, postaction={decorate},decoration={markings,mark=at position .5 with {\draw (-2pt,-2pt) -- (2pt,2pt);\draw (2pt,-2pt) -- (-2pt,2pt);}}},
  fermion/.style={draw=black, postaction={decorate},decoration={markings,mark=at position .55 with {\arrow{>}}}},
  weak/.style={dashed, draw=black},
  special/.style={decorate,decoration={shape backgrounds,shape=circle,shape size=0.5pt,shape sep=2pt}},
  gluon/.style={decorate, draw=black,decoration={coil,amplitude=4pt, segment length=5pt}} ,
  hadron/.style={
    draw=black,
    postaction={
        decoration={contour lineto, contour distance=-2pt},
        draw=black, decorate},
    postaction={
        decoration={contour lineto, contour distance=2pt}, 
        draw=black, decorate}
  },
  meson/.style={
    draw=none,
    postaction={
        decoration={contour lineto, contour distance=-1pt},
        draw=black,decorate},
    postaction={
        decoration={contour lineto, contour distance=1pt}, 
        draw=black, decorate},
  },
  vertex/.style={draw,shape=circle,fill=black,minimum size=3pt,inner sep=0pt},
  bbvertex/.style={draw,shape=circle,pattern=north east lines,very thin,minimum size=12pt,inner sep=0pt}
}

\newcommand{\generateShower}[1]{
  \scalebox{.3}{
    \pgfmathsetseed{#1}
    \begin{forest}
      random tree/.style n args={2}{% #1=max levels, #2=max children
        if={##1>0}{repeat={random(0,##2)}{append={[,random tree={##1-1}{##2}]}}}{},
        parent anchor=center, child anchor=center, grow=north},
      [,random tree={3}{3}]
    \end{forest}
  }
}

Actual picture

\begin{tikzpicture}[node distance=1cm and 0.4cm]
%% the bottom part
\coordinate[vertex] (sv);
\coordinate[vertex,   below      =1cm and 0.4cm of sv] (pv);
\coordinate[bbvertex, below left =1cm and 0.4cm of pv] (vl);
\coordinate[bbvertex, below right=1cm and 0.4cm of pv] (vr);
\coordinate[          below left =1cm and 0.4cm of vl] (il);
\coordinate[          below right=1cm and 0.4cm of vr] (ir);
\coordinate[          above left =1cm and 0.4cm of vl] (fl);
\coordinate[          above right=1cm and 0.4cm of vr] (fr);
\draw[hadron] (il) -- (vl);
\draw[meson]  (vl) -- (fl);
\draw[fermion](vl) -- (pv);
\draw[hadron] (ir) -- (vr);
\draw[meson]  (vr) -- (fr);
\draw[fermion](pv) -- (vr);
%% the connecting line
\draw[photon] (pv) -- (sv);
%% the top part
\coordinate[  vertex,above right=2cm and 2.0cm of sv] (r);
\coordinate[  vertex,above left =0.5cm and 0.7cm of r] (rl);
\coordinate[  vertex,above right=0.5cm and 1.0cm of rl] (rlr);
\coordinate[  vertex,above left =0.5cm and 1.0cm of rl] (rll);
\coordinate[  vertex,above left =1cm and 1.0cm of sv] (l);
\coordinate[  vertex,above left =1cm and 1.0cm of l] (ll);
\coordinate[  vertex,above right=2cm and 0.5cm of l] (lr);
\coordinate[bbvertex,above left =1cm and 1.0cm of lr] (lrl);
\coordinate[bbvertex,above right=1cm and 0.2cm of lr] (lrr);
\coordinate[bbvertex,above left =2cm and 2.0cm of ll] (lll);
\coordinate[  vertex,above right=1cm and 0.5cm of ll] (llr);
\coordinate[bbvertex,right=1cm of lrr] (rlrl);
\coordinate[bbvertex,right=2.5cm of rlrl] (rr);
%% tree-level fermion lines
\draw[fermion] (lll) -- (ll);
\draw[fermion] (ll) -- (l);
\draw[fermion] (l) -- (sv);
\draw[fermion] (sv) -- (r);
\draw[fermion] (r) -- (rr);
%% connection gluons
\draw[gluon] (r) -- (rl);
\draw[gluon] (l) -- (lr);
\draw[gluon] (rl) -- (rll);
\draw[gluon] (rl) -- (rlr);
\draw[gluon] (ll) -- (llr);
%% branch-level fermion lines
\draw[fermion] (rr) -- (rlr);
\draw[fermion] (rlr) -- (rlrl);
\draw[fermion] (rlrl) -- (rll);
\draw[fermion] (rll) -- (lrr);
\draw[fermion] (lrr) -- (lr);
\draw[fermion] (lr) -- (lrl);
\draw[fermion] (lr) -- (lrl);
\draw[fermion] (lrl) -- (llr);
\draw[fermion] (llr) -- (lll);
%% decay chains for bb vertices: rr, lrl, lrr, lll, rlrl
\node[yshift=-5.5pt,xshift=-1.5pt,anchor=south] at (lll.north) {\generateShower{33333}};
\node[yshift=-5.5pt,xshift=-3pt,anchor=south]   at (lrl.north) {\generateShower{25763}};
\node[yshift=-5.5pt,xshift=2pt,anchor=south]    at (lrr.north) {\generateShower{76924}};
\node[yshift=-5.5pt,xshift=-4pt,anchor=south]   at (rlrl.north){\generateShower{45678}};
\node[yshift=-5.5pt,xshift=-1.5pt,anchor=south] at (rr.north)  {\generateShower{14285}};
%% lhs braces
\draw [decorate,decoration={brace,amplitude=5pt}] (-5,-3.5) -- (-5,-1.5)    
node [black,midway,xshift=-0.8cm,left,text width=3cm,align=right] {parton\\distributions};
\draw [decorate,decoration={brace,amplitude=5pt}] (-5.5,-1.5) -- (-5.5,0.5) 
node [black,midway,xshift=-0.3cm,left,text width=3cm,align=right] {hard\\scattering};
\draw [decorate,decoration={brace,amplitude=5pt}] (-5,0.4) -- (-5,3.8)      
node [black,midway,xshift=-0.8cm,left,text width=3cm,align=right] {parton\\shower};
\draw [decorate,decoration={brace,amplitude=5pt}] (-5.5,3.7) -- (-5.5,4.7)  
node [black,midway,xshift=-0.3cm,left,text width=3cm,align=right] {hadronization};
\draw [decorate,decoration={brace,amplitude=5pt}] (-5,4.6) -- (-5,5.7)      
node [black,midway,xshift=-0.8cm,left,text width=3cm,align=right] {decay};
\end{tikzpicture}

Result

!Schematic illustration of the basic structure of a events simulated with a
showering and hadronisation generator. The time
evolution of the event goes from bottom to top.

Best Answer

This is an example modified based on page 1 of the forest package documentation.

Note the default anchors of the forest package is not the center of a node, and thus there appear to be white spaces between edges. To fix this, set both parent anchor and child anchor to center, so that they can "connect" with each other. The grow key specifies the direction to which the tree should grow. Since you want it to grow upwards, grow=north would do the trick.

\documentclass[border=2pt]{standalone}

\usepackage{forest}

\begin{document}
\pgfmathsetseed{14285}
\begin{forest}
random tree/.style n args={2}{% #1=max levels, #2=max children
if={#1>0}{repeat={random(0,#2)}{append={[,random tree={#1-1}{#2}]}}}{},
  parent anchor=center, child anchor=center, grow=north},
[,random tree={4}{3}]
\end{forest}
\end{document}

enter image description here

Update: Attaching tree to another node

This is probably not the best way to attach a forest tree to another tikz node, but it's the only thing I can come up with that works.

The idea is to put the forest tree inside a node, and use node positioning commands to "attach" it to another node. The main imperfection is that you have to manually adjust the yshift and \scalebox parameters. (I've tried using inner sep=0pt and outer sep=0pt. But those screwed up the forest picture.)

\documentclass{standalone}
\usepackage{forest}

\begin{document}

\pgfmathsetseed{12987}

\begin{tikzpicture}
  \node(s)[circle,fill=red]{some node};
  \node[yshift=-5.5pt,anchor=south]at(s.north){
    \scalebox{.5}{
      \begin{forest}
        random tree/.style n args={2}{% #1=max levels, #2=max children
        if={#1>0}{repeat={random(0,#2)}{append={[,random tree={#1-1}{#2}]}}}{},
        parent anchor=center, child anchor=center, grow=north},
        [,random tree={3}{3}]
      \end{forest}
    }
  };
\end{tikzpicture}

\end{document}

enter image description here

Related Solutions

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

The source of the difficulty is that ellipses are constructed in a particular way in TikZ. They are paths that start from the x-axis and proceed counter-clockwise around their centre. The vast majority of the time, the exact parametrisation doesn't matter. You appear to have found the one situation where it does!

In the actual question, you only want to be able to mirror the ellipse, and so draw it starting from the negative x-axis (the title of the question suggests a more flexible approach). That's actually not too hard since we can exploit the symmetry of the ellipse. The key is to provide it with a negative x-radius, since then it will start from the negative x-axis (and proceed clockwise, but we could correct for that by negating the y-radius as well). To do this, we interrupt the call from the node shape to the drawing command and flip the sign of the x-radius. The simplest way to do this is to redefine the \pgfpathellipse macro to do the negation and then call the original macro. The following code does this.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations,shapes,decorations.markings}
\makeatletter
\let\origpgfpathellipse=\pgfpathellipse
\def\revpgfpathellipse#1#2#3{%
  #2%
  \pgf@xa=-\pgf@x
  \origpgfpathellipse{#1}{\pgfqpoint{\pgf@xa}{0pt}}{#3}}
\makeatother

\tikzset{
  reversed ellipse/.style={
    ellipse,
    reverse the ellipse%
  },
  reverse the ellipse/.code={
    \let\pgfpathellipse=\revpgfpathellipse
  }
}
\begin{document}
\begin{tikzpicture}
\node[ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,0) {hello world};

\node[reversed ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,-2) {hello world};
\end{tikzpicture}

\end{document}

Here's the result:

rotated ellipse

(the arrow got clipped, but you can see where it lies)

[Tex/LaTex] Randomized coordinates in TikZ

The problem is that, inside your \bacterium macro you use a \tikz{} command to draw the bacterium. This command creates its own picture, so that each bacterium has its own coordinate system. In this coordinate system the bacteriumm is placed randomly, but then that picture is cropped to the size of the bacterium, so there is no difference if the bacterium is located at (30,10) or at (0,0), becacuse after the cropping it will look the same. In addition, you wrap that picture inside a \scalebox, which makes the whole picture to be treated as a single character.

The main for loop invokes \bacterium to create that set of pictures, and places them one after the other, as when composing a word from several characters.

As it was said other times at other places, it is not a good idea to nest tikz pictures.

What you need is that all the bacteria share the same coordinate system, i.e. they are all in the same tikz picture. The following code achieves this goal, by replacing your \tikz command by a tikz scope which allows the specification of a scale factor and a rotation factor.

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usetikzlibrary{calc,decorations,decorations.pathreplacing}
\begin{document}
\newcommand{\bacterium}[3]{
    \begin{scope}[scale=#2, rotate=#3]
    \coordinate (A) at (#1);
    \shadedraw[shading=ball,ball color=yellow!75, white,
              rounded corners=10*#2](A) rectangle++(1.5,.65);
    \draw[decorate,decoration={snake,amplitude=1mm}]
              (A)++(0,.75*.5)--++(-1,0);
\end{scope}
}


\pgfmathsetseed{1}
\begin{tikzpicture}
  \foreach \x in {1,2,...,10}{
    \bacterium{rand*10,rand*10}{.2}{rand*360}}
\end{tikzpicture}
\end{document}

Result

Edit

Edit 2

Preparation

Actual picture

Result

Best Answer

Related Solutions

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

[Tex/LaTex] Randomized coordinates in TikZ

Related Question