如何合并单元格边框（在网格中绘制墙壁）？

Question

我想在网格上画一堵墙。目前我有这：

    %based on https://tex.stackexchange.com/a/91429/69931 
\documentclass[usenames,dvipsnames]{article}
    \usepackage{tikz}
    \usetikzlibrary{backgrounds}
    \usepackage{graphicx}
    \usepackage[margin=0cm,nohead]{geometry} 
    \usepackage[active,tightpage]{preview} 
    \PreviewEnvironment{tikzpicture}

    \usetikzlibrary{fit}
% Some customizable styles
    \tikzset {
        highlight/.style = {yellow, opacity=0.3},
        digit/.style = {minimum height = 5mm, minimum width=5mm, anchor=center },
        circle/.style = {draw=green!80!black, dotted, very thick},
        circle number/.style = {draw=#1,very thick},
        cross/.style = {red, opacity=.5, shorten >=1mm, shorten <=1mm, very thick, line cap=round},
        hint/.style={blue, font=\sf, minimum width=3mm, minimum height=3mm}
    }

    \newcounter{hi}
    \setcounter{hi}{5}

    \newcounter{row}
    \newcounter{col}

    \newcommand\setrow[9]{
        \setcounter{col}{1}
        \foreach \n in {#1, #2, #3, #4, #5, #6, #7, #8, #9} {
            \edef\x{\value{col} - 0.5}
            \edef\y{\value{hi} + 0.5 - \value{row}}
            \node[digit,name={\arabic{row}-\arabic{col}}] at (\x, \y) {\n};
            \stepcounter{col}
        }
        \stepcounter{row}
    }

    \def\wallcells#1{
        \node[draw=black,thick, fill=black!50, opacity=0.5, fit=#1,inner sep=0pt] {};
    }

\begin{document}

    \begin{tikzpicture}[scale=.5]
        \begin{scope}
            \draw (0, 0) grid (9, \value{hi});
            \setcounter{row}{1}
            \setrow {}{}{}  {}{}{}  {}{}{}
            \setrow {}{}{}  {}{}{}  {}{}{}
            \setrow {}{}{}  {}{}{}  {}{}{}

            \setrow {}{}{}  {}{}{}  {}{}{}
            \setrow {}{}{}  {}{}{}  {}{}{}
        \end{scope}

    \wallcells{(1-3) (1-6)}
    \wallcells{(1-5) (3-5)}

\end{tikzpicture}
\end{document}

然而，我想要的是无缝墙壁合并（相同的透明灰色，仅单边框围绕墙壁单元）：

Answer 1

我不知道有任何自动解决方案可以解决这个叠加问题。但是这里有一个手动解决方案。

网格用 绘制matrix of empty nodes。要填充的节点在 内.list用特定的声明style。最后，使用围绕已填充矩阵节点的垂直线段手动绘制边框。

\documentclass[tikz,border=2mm]{standalone}
\usetikzlibrary{matrix}
\begin{document}
\begin{tikzpicture}[
    mygrid/.style={
        matrix of nodes,
        nodes in empty cells,
        nodes={draw, minimum size=1cm},
        column sep=-\pgflinewidth,
        row sep=-\pgflinewidth},
    myset/.style args= {(#1,#2)}{%
        row #1 column #2/.style={nodes={fill=red!30, opacity=.5}}}
        ]

\matrix (A) [mygrid, myset/.list={(1,3),(1,4),(1,5),(1,6),(2,5),(3,5)}]{
    &&&&&&&&\\ 
    &&&&&&&&\\ 
    &&&&&&&&\\
    &&&&&&&&\\ 
    &&&&&&&&\\ 
    };

\draw[opacity=.5, ultra thick, red] (A-1-3.north west)-|
   (A-1-6.south east)-|
   (A-3-5.south east)-|
   (A-1-5.south west)-|cycle;
\end{tikzpicture}
\end{document}