How to stack rows of nodes in TikZ?

Question

I am try to create a diagram similar to the following in Tikz:

I know how to create each individual row I think, I'm doing something similar to:

\tikzstyle{cell} = [rectangle, rounded corners=5pt, thick, draw, text width=0.65cm ]
\node [cell, text width=8.7cm] (n1) {Z};

I figured I could stack them with something like:

\node [cell, text width=8.7cm] (n1) [above=of n2]{Z};                                                                                 
\node [cell, text width=4.1cm] (n2) {X};                                                                                              
\node [cell, text width=4.1cm] (n3) [right=of n2] {Y};

but that doesn't stack them the way I want to. I've seen similar answers using stuff like "above right", etc. but those seem to place them diagonally instead of aligned like the picture above.

Any help would be appreciated - thanks!

Answer 1

I think that a tikz matrix and the fit library could help you.

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{fit, matrix, shapes.geometric}
\tikzset{% use tikzset, not tikzstyle
    cell/.style={
        rectangle, rounded corners=5pt, thick, draw,
    }
}
\begin{document}
    \begin{tikzpicture}
        \matrix[
            matrix of nodes, nodes in empty cells,
            minimum width=2cm,
            column sep=4pt,
            row sep=10pt,
            text height=2ex,text depth=.25ex,
            minimum height=4ex
            ] (m) {
            & & & \\
            & & & \\
            |[cell]| A & |[cell]| B & |[cell]| C & |[cell]| D \\
        } ;
        \node[cell, fit=(m-2-1)(m-2-2), inner sep=0pt, label=center: X] {};
        \node[cell, fit=(m-2-3)(m-2-4), inner sep=0pt, label=center: Y] {};
        \node[cell, fit=(m-1-1)(m-1-4), inner sep=0pt, label=center: Z] {};        
    \end{tikzpicture}
\end{document}

Credits for the label=center: goes to Why is the text of this node not vertically centered?.

Answer 2

This is a variation from CarLaTeX solution. It uses a matrix for the bottom row, but upper rows are built with a fit node placed with positioning library.

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{fit, matrix, positioning, shapes.geometric}
\tikzset{% use tikzset, not tikzstyle
    cell/.style={
        minimum width=2cm,
        text height=2ex,text depth=.25ex,
        minimum height=4ex,
        rectangle, rounded corners=5pt, thick, draw,
    }
}
\begin{document}
    \begin{tikzpicture}
        \matrix[
            matrix of nodes,
            nodes = {cell, align=center},
            column sep=4pt,
            ] (m) {
            A & B & C & D \\
        } ;
        \node[cell, fit=(m-1-1)(m-1-2), inner sep=0pt, label=center: X, above left = 10pt and 0pt of m-1-2.north east] (X) {};
        \node[cell, fit=(m-1-3)(m-1-4), inner sep=0pt, label=center: Y, above left = 10pt and 0pt of m-1-4.north east] (Y) {};
        \node[cell, fit=(X)(Y), inner sep=0pt, label=center: Z, above left = 10pt and 0pt of Y.north east] {};        
    \end{tikzpicture}
\end{document}

Following solution uses a tcbraster from tcolorbox package.

\documentclass{article}

\usepackage[most]{tcolorbox}

\tcbset{enhanced, fontupper=\bfseries, notitle, halign=center, valign=center}

\begin{document}
\begin{tcbitemize}[%
    raster width=10cm,
    raster equal height=rows, 
    raster columns=4,
    raster equal height,
    raster every box/.style={height=4ex},
    raster column skip=10pt,
    raster row skip=4pt,
    colback=white]
\tcbitem[raster multicolumn=4] Z
\tcbitem[raster multicolumn=2] X
\tcbitem[raster multicolumn=2] Y
\tcbitem A
\tcbitem B
\tcbitem C
\tcbitem D
\end{tcbitemize}
\end{document}

Answer 3

With nested loops, no TikZ matrix, nor any TikZ library.

I use the nice label=center:#1 trick suggested by Carla.

It is certainly possible to manage both node length and coordinates xscale better, but I don't know how off the top of my head.

The output

The code

\documentclass[12pt,tikz]{standalone}
\begin{document}
\tikzset
{
  cell/.style=
  {
    rectangle,
    rounded corners=5pt,
    thick,
    draw,
    anchor=west,
    inner xsep=-2pt,
    minimum height=.7cm,
  }
}
\def\xScale{7cm}
\begin{tikzpicture}[x=\xScale]
  \foreach \k/\v in {0/{0/Z},1/{0/X,1/Y},2/{0/A,1/B,2/C,3/D}}
  {
    \foreach \kk/\vv in \v
    {
        \node 
        [
          cell,
          text width=1/2^\k * \xScale,
          label=center:\vv,
        ]
        at (\kk/2^\k,-\k)
        {};
    }
  }
\end{tikzpicture}
\end{document}

Answer 4

as forest tree ... (adopted example from its documentation, page 29):

\documentclass[margin=3mm]{standalone}
\usepackage{forest}

\begin{document}
\forestset{box/.style={
  draw, rounded corners, minimum width=12mm,
  no edge,
  l=0, l sep=1mm,
  s=0, s sep=1mm,
  calign=first, anchor=base west,
  % content format={\strut\forestoption{content}},
  if n children=0{}{
    after packing node={
      minimum width/.pgfmath=
        {s("!l")+max_x("!l")-s("!1")-min_x("!1")},
      for children/.wrap pgfmath arg={s+={##1}}{0},
      typeset node}}}}
\begin{forest} for tree={box}
[Z
  [X
    [A][B]
  ]
  [Y
    [C]
    [D]
  ]
]
\end{forest}
\end{document}