Tikz: Animate creation of nodes in a defined rectangle/box

Question

I want to let text nodes pop-up at random positions in a defined part/box of a beamer slide automatically. Currently, I store the strings with the node texts in an array and iterate over the array using a foreach loop.

My issues:

• All node locations are re-calculated for each loop step. Due to rand in the node location already visible nodes also get new coordinates. Can I have fixed coordinates for already visible nodes?
• How do I make the tikzpicture use the complete right column?
• Is it possible to animate that overlay on one slide/frame by making each node visible after a certain time instead of having to click for every single overlay?

---

MWE

\documentclass{beamer}

\usepackage{tikz}
\usetikzlibrary{calc}
\usetikzlibrary{fit}
\usetikzlibrary{positioning}
\usetikzlibrary{shapes}

\begin{document}

\begin{frame}[t]{test}

\begin{columns}
  \begin{column}{0.39\textwidth}
    \begin{itemize}
      \item Some text
    \end{itemize}
  \end{column}
  \begin{column}{0.6\textwidth}
    \centering

    \def\namelist{{"test1","test2","test3","test4","test5","test6","test7"}}%

    \tikzset{%
      cloudstyle/.style={%
        cloud,
        cloud puffs=11.5,
        aspect=3,
        align=center,
        inner sep=0pt,
        draw,
        fill=lightgray,
      }%
    }

    \begin{tikzpicture}
      \foreach \i in {0,...,3} {
        \pgfmathtruncatemacro\z{\i+1}
        \visible<\z->{
          \pgfmathsetmacro\mynodename{\namelist[\i]}
          \node[cloudstyle] (\mynodename) at (rand,rand) {\mynodename};
        }
      }
    \end{tikzpicture}
  \end{column}
\end{columns}

\end{frame}

\end{document}

---

How it could look like

Answer 1

In this code, a list is created once and for all with a command

\CreateRandomCoordinateList{<list>}{<# of entries>}{<prefactor x>}{<prefactor y>}

The second trick is to add a bounding box to the picture since otherwise the nodes appear to jump. (One could also write a solution without a bounding box.) The following produces an animation. To have it automatically animate, use acroread in the full screen mode. \transduration<2-6>{1} indicates that there is 1 second between the steps.

\documentclass{beamer}

\usepackage{tikz}
\usetikzlibrary{calc}
\usetikzlibrary{fit}
\usetikzlibrary{positioning}
\usetikzlibrary{shapes,overlay-beamer-styles}
\newcommand{\CreateRandomCoordinateList}[4]{
\foreach \X in {1,...,#2}
 {\pgfmathsetmacro{\myx}{rand*#3}
\pgfmathsetmacro{\myy}{rand*#4}
\ifnum\X=1
 \xdef#1{(\myx,\myy)}
\else
 \xdef#1{#1,(\myx,\myy)}
\fi}    
}
\begin{document}
\CreateRandomCoordinateList{\lstRnd}{6}{2}{2}
%\typeout{\lstRnd}
\newcount\NumClouds
\begin{frame}[t]{test}
\animate<2-6>
\animatevalue<1-6>{\NumClouds}{1}{6}  
\transduration<2-6>{1}
\begin{columns}
  \begin{column}{0.39\textwidth}
    \begin{itemize}
      \item Some text
    \end{itemize}
  \end{column}
  \begin{column}{0.6\textwidth}
    \centering

    \edef\namelist{{"test1","test2","test3","test4","test5","test6","test7"}}%

    \tikzset{%
      cloudstyle/.style={%
        cloud,
        cloud puffs=11.5,
        aspect=3,
        align=center,
        inner sep=0pt,
        draw,
        fill=lightgray,
      }%
    }

    \begin{tikzpicture}
      \path[use as bounding box] (-1,-1) rectangle (3,3);
      \foreach \Coord [count=\z,evaluate=\z as \i using {int(\z-1)}] in
      \lstRnd {
          \pgfmathsetmacro\mynodename{\namelist[\i]}
          \ifnum\i<\NumClouds
            \node[cloudstyle] (\mynodename) at \Coord {\mynodename};
          \fi
      }
    \end{tikzpicture}
  \end{column}
\end{columns}

\end{frame}

\end{document}

And this is a slight variation in which I use Jake's code to build a list of coordinates such that the clouds do not overlap.

\documentclass{beamer}

\usepackage{tikz}
\usetikzlibrary{calc}
\usetikzlibrary{fit}
\usetikzlibrary{positioning}
\usetikzlibrary{shapes,overlay-beamer-styles}
% from https://tex.stackexchange.com/a/87518/121799
\def\xlist{2}
\def\ylist{2}

\newcommand{\fillrandomly}[4]{
    \pgfmathsetmacro\diameter{#3*2}
    %\draw (0,0) rectangle (#1,#2);
    \foreach \i in {1,...,#4}{
        \pgfmathsetmacro\x{rnd*#1}
        \pgfmathsetmacro\y{rnd*#2}
        \xdef\collision{0}
        \foreach \element [count=\i] in \xlist{
            \pgfmathtruncatemacro\j{\i-1}
            \pgfmathsetmacro\checkdistance{ sqrt( 0.25*({\xlist}[\j]-(\x))^2 + ({\ylist}[\j]-(\y))^2 ) }
            \ifdim\checkdistance pt<\diameter pt
                \xdef\collision{1}
                \breakforeach
            \fi
        }
        \ifnum\collision=0
            \xdef\xlist{\xlist,\x}
            \xdef\ylist{\ylist,\y}
            %\draw [red, thick] (\x,\y) circle [radius=#3];
        \fi 

    }
}



\begin{document}
% creates random list
\fillrandomly{6}{8}{0.6}{7}
%\typeout{xlist=\xlist,ylist=\ylist}

\begin{frame}[t]{test}

\begin{columns}
  \begin{column}{0.39\textwidth}
    \begin{itemize}
      \item Some text
    \end{itemize}
  \end{column}
  \begin{column}{0.6\textwidth}
    \centering

    \edef\namelist{{"test1","test2","test3","test4","test5","test6","test7"}}%

    \tikzset{%
      cloudstyle/.style={%
        cloud,
        cloud puffs=11.5,
        aspect=3,
        align=center,
        inner sep=0pt,
        draw,
        fill=lightgray,
      }%
    }

    \begin{tikzpicture}[scale=0.5]
      \path[use as bounding box] (-1,-1) rectangle (7,9);
      \foreach \X [count=\z,evaluate=\z as \i using {int(\z-1)}] in
      \xlist {
        \pgfmathsetmacro{\Y}{{\ylist}[\i]}
        \pgfmathsetmacro\mynodename{\namelist[\i]}
        %\typeout{x=\X,y=\Y,name=\mynodename}
        \node[cloudstyle,visible on=<\z->] (\mynodename) at (\X,\Y) {\mynodename};
      }
    \end{tikzpicture}
  \end{column}
\end{columns}

\end{frame}

\end{document}