[Tex/LaTex] Subdividing and Filling a Tikz Rectangle

tikz-pgf

I have two nodes (drawn as rectangles) in my picture, one filled in green, the other red. I wish to produce a third 'rectangle' which shows the effect of splicing these two rectangles and stitching them back together.

Or, in other words, I wish to produce a rectangle twice the width of my starting rectangles that is subdivided up into smaller segments, each segment filled alternating between red and green.

Given my picture:

\begin{tikzpicture}[node distance=5mm]
  \node [fill=red!30,minimum width=40mm] (b1) {Bank 1 \unit[1024]{MiB}};
  \node [fill=green!30,minimum width=40mm,right=of b1] (b2) {Bank 2 \unit[1024]{MiB}};
\end{tikzpicture}

I have been able to 'create' the desired effect using two \foreach loops:

\foreach \n in {0,2,...,10}
  \draw [fill=red!30] (\n*6.66mm,1) +(-3.33mm,0) rectangle
  ++(3.33mm,5mm);
\foreach \n in {1,3,...,11}
  \draw [fill=green!30] (\n*6.66mm,1) +(-3.33mm,0) rectangle
  ++(3.33mm,5mm);

However, this requires several manual factors (40 / 6 = 6.66, 6.66 / 2 = 3.33) and I have been unable to position it under my existing two nodes due to the use of absolute coordinates.

Are there better ways of doing this which would give me more/easier control of the positioning of the 'group'? I looked into splitting a rectangle but this is seemingly limited to four horizontal splits.

Best Answer

You could use a chain and position the first node in the chain using the anchors of the unsplit nodes: 

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



\begin{document}

\newlength\nodewidth
\setlength\nodewidth{40mm}

\tikzset{%
    fill1/.style={fill=red!30,outer sep=0pt},
    fill2/.style={fill=green!30,outer sep=0pt},
    split/.style={%
        minimum width=0.5/3*\nodewidth,
        minimum height=5mm,
        %inner sep=0pt,
        outer sep=0pt,
        on chain},
    split1/.style={split,fill1},
    split2/.style={split,fill2},
}

\begin{tikzpicture}[%
    start chain,
    node distance=0pt]

    \node [fill1,minimum width=\nodewidth] (b1) {Bank 1 1024 MiB};
    \node [fill2,minimum width=\nodewidth,right=of b1] (b2) {Bank 2 1024 MiB};

    \node [split1,anchor=north west] at (b1.south west) {};
    \node [split2] {};
    \foreach \n in {0,1,...,4} {%
        \node [split1] {};
        \node [split2] {};
    };

\end{tikzpicture}

\end{document}
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