How To Color A Single Multicolumn Cell

Question

I am trying to color individual cells inside of a table containing multicolumn cells, however Using \colorcell, or \columncolor results in cells which have white padding on the right hand side.

I have found relevant questions, however they all seem to be concerned with coloring non-multicolumn cells within a table containing multicolumns. However I am concerned with coloring the multicolumn cell itself.

ie.

Table cell color overlaps left cell border of first column which is multicolumn

How to color only one cell in a multicolumn table?

I have tried the following, however none of them quite work. The method with setting \tabcolsep to 0pt is the closest to wht I want, however I don't like how the text goes all the way to the vertical line.

\documentclass{report}
  \usepackage[margin=1in,headheight=.5in,headsep=0.25in]{geometry} 
  \usepackage{tabularx,colortbl,ltablex}
  \renewcommand\tabularxcolumn[1]{m{#1}}% for vertical centering text in X column
  \newcolumntype{C}{>{\centering\arraybackslash}X}

\newcommand{\cell}[2]{\multicolumn{#1}{|>{\hsize=#1\hsize}C|}{#2}}
\newcommand{\colorcell}[2]{\multicolumn{#1}{|>{\columncolor{red}\hsize=#1\hsize}C|}{#2}}
\newcommand{\colorcellb}[2]{\multicolumn{#1}{|>{\columncolor{red}[\tabcolsep][#1\tabcolsep]\hsize=#1\hsize}C|}{#2}}

\begin{document}
\keepXColumns

Standard Column Color
\begin{tabularx}{\textwidth}{|*{8}{C|}}
  \hline
  7&6&5&4&3&2&1&0\\
  \hline
  \colorcell{1}{ a a a a a a a a a a a a}&\cell{1}{CLEAR}&\colorcell{2}{Colored Cell}&\cell{1}{CLEAR}&\colorcell{3}{Colored Cell}\\
  \hline
\end{tabularx}

ColumnColor + Overhangs
\begin{tabularx}{\textwidth}{|*{8}{C|}}
  \hline
  7&6&5&4&3&2&1&0\\
  \hline
  \colorcellb{1}{ a a a a a a a a a a a a}&\cell{1}{CLEAR}&\colorcellb{2}{Colored Cell}&\cell{1}{CLEAR}&\colorcellb{3}{Colored Cell}\\
  \hline
\end{tabularx}

TabColSep=0
\setlength{\tabcolsep}{0 pt}
\begin{tabularx}{\textwidth}{|*{8}{C|}}
  \hline
  7&6&5&4&3&2&1&0\\
  \hline
  \colorcell{1}{ a a a a a a a a a a a a}&\cell{1}{CLEAR}&\colorcell{2}{Colored Cell}&\cell{1}{CLEAR}&\colorcell{3}{Colored Cell}\\
  \hline
\end{tabularx}

\end{document}

score 3 · Answer 1 · answered Aug 28 '18 at 14:58

like this:

in calculation of multi column width you forgoth on \tabcolsep and \arrayrulewidth. considering them in your definition of new comeands cell (actually is unnecessary in your mwe)- considering it your mwe become:

\documentclass{report}
\usepackage[margin=1in,headheight=.5in,headsep=0.25in]{geometry}
\usepackage[table]{xcolor}
\usepackage{ltablex}
\keepXColumns
\renewcommand\tabularxcolumn[1]{m{#1}}% for vertical centering text in X column
\newcolumntype{C}{>{\centering\arraybackslash}X}

\newcommand{\cell}[2]{\multicolumn{#1}{|>{\hsize=%
    \dimexpr#1\linewidth+#1\tabcolsep+#1\tabcolsep-#1\arrayrulewidth}C|}{#2}}
\newcommand{\colorcell}[2]{\multicolumn{#1}{|>{\columncolor{red}\hsize=%
    \dimexpr#1\linewidth+#1\tabcolsep+#1\tabcolsep-#1\arrayrulewidth}C|}{#2}}

\begin{document}

Standard Column Color

\begin{tabularx}{\textwidth}{|*{8}{C|}}
  \hline
  7 & 6 & 5 & 4 & 3 & 2 & 1 & 0     \\
  \hline
  \colorcell{1}{ a a a a a a a a a a a a}
    &  CLEAR
        &   \colorcell{2}{Colored Cell}
            &   CLEAR
                &   \colorcell{3}{Colored Cell}     \\
  \hline
\end{tabularx}

\end{document}

Thank You!! I would mark as accepted, but apparently asked from an unregistered account — DanChianucci, Aug 28 '18 at 15:27
@DanChianucci, don't rush with acceptance :-), however register your account :-) — Zarko, Aug 28 '18 at 15:30

score 0 · Answer 2 · answered Nov 03 '23 at 09:39

You can easily create that table with {NiceTabular} of nicematrix.

\documentclass{report}
\usepackage[margin=1in,headheight=.5in,headsep=0.25in]{geometry}
\usepackage{nicematrix}
\begin{document}
\noindent
\begin{NiceTabular}{*{8}{X[c,m]}}[hvlines,color-inside]
 7 & 6 & 5 & 4 & 3 & 2 & 1 & 0 \
\cellcolor{red} a a a a a a a a a a a a 
& CLEAR 
& \Block[fill=red]{1-2}{Colored Cell} & 
& CLEAR
& \Block[fill=red]{1-3}{Colored Cell} & 
\end{NiceTabular}
\end{document}

You need several compilations (because nicematrix uses PGF/TikZ nodes under the hood).

How To Color A Single Multicolumn Cell

2 Answers2

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