Coloring columns in a table with colortbl and booktabs

Question

I have created a rather complicated table with some columns that I want to color. For the table, I chose the booktabs and tabularx packages. For coloring the columns, I use colortbl.

The problem that I have is that \midrules show a white space, and the result does not please me at all. Here is a MWE:

\documentclass[a5paper]{article}
\usepackage{xcolor}
\usepackage{booktabs,colortbl,tabularx}
\begin{document}
\pagestyle{empty}
\begin{table*}[!htb]
  \centering
  \begin{tabularx}{4cm}{>{\columncolor{gray}}cX>{\columncolor{gray}}c}
    \toprule
    1&2&3\\
    \midrule
    one&two&three\\
    one&two&three\\
    \cmidrule{2-3}
    one&two&three\\
    \midrule
    un&deux&trois\\
    \bottomrule
  \end{tabularx}
  \caption{caption}
\end{table*}
\end{document}

Looking around I found that booktabs supports colortbl in its latest version. However, it seems that it only supports colored horizontal lines.

I tried not using booktabs and replacing midrules for hlines. My huge table looks too crowded (once you booktab, you never go back, I guess).

My question is: is it possible to achieve a correct coloring in midrules ? Since I fear that the response is no: what low-cost recommendation do you have in order to color the columns of my table?

(When I say low-cost, I mean that I do not want to re-write my table contents)

Answer 1

There's no way to do this given the way booktabs inserts space between above and below its rules. As Herbert notes inthe comments, it's not clear that rules and colours are really a logical combination. So probably the best you can do is to increase the row height and set the space above and below the rules to 0.

\documentclass{article}
\usepackage{xcolor}
\usepackage{booktabs,colortbl,tabularx}

\begin{document}
% Your original table
  \begin{tabularx}{4cm}{>{\columncolor{gray}}cX>{\columncolor{gray}}c}
    \toprule
    1&2&3\\
    \midrule
    one&two&three\\
    one&two&three\\
    \cmidrule{2-3}
    one&two&three\\
    \midrule
    un&deux&trois\\
    \bottomrule
  \end{tabularx}
% same table with booktab rules but no above space and making rows bigger
\setlength{\aboverulesep}{0pt}
\setlength{\belowrulesep}{0pt}
\setlength{\extrarowheight}{.75ex}
  \begin{tabularx}{4cm}{>{\columncolor{gray}}cX>{\columncolor{gray}}c}
    \toprule
    1&2&3\\
    \midrule
    one&two&three\\
    one&two&three\\
    \cmidrule{2-3}
    one&two&three\\
    \midrule
    un&deux&trois\\
    \bottomrule
  \end{tabularx}
% same table without booktab rules
\setlength{\extrarowheight}{.75ex}
  \begin{tabularx}{4cm}{>{\columncolor{gray}}cX>{\columncolor{gray}}c}
    \hline
    1&2&3\\
    \hline
    one&two&three\\
    one&two&three\\
    \cline{2-3}
    one&two&three\\
    \hline
    un&deux&trois\\
    \hline
  \end{tabularx}
\end{document}

The middle table still looks marginally better than the third one.

Answer 2

Rules and colour in a tabular is not necessary, as it is said in the note, but if you nevertheless insist using it, the package cals is able to handle both:

\documentclass{article}
\usepackage{cals}
\usepackage{xcolor}

\begin{document}

\begin{table*}[!htb]
\begin{calstable}[c]
% Defining columns 
\colwidths{{1.5cm}
            {2.25cm}
            {1.75cm}
            }

% Set up the tabular
\makeatletter
\def\cals@framers@width{0.8pt}   % Outside frame rules, reduce if the rule is too heavy
\def\cals@framecs@width{0pt}
\def\cals@bodyrs@width{0.4pt}    % "midrule" - line between heading and body
\cals@setpadding{Ag}
\cals@setcellprevdepth{Al}
\def\cals@cs@width{0pt}             % Inside rules, reduce if the rule is too heavy
\def\cals@rs@width{0.6pt}
\def\cals@bgcolor{}

\def\gray{\ifx\cals@bgcolor\empty     % "Switch" to turn on and off colour
    \def\cals@bgcolor{gray!50}
\else \def\cals@bgcolor{} \fi}

\def\bb{\ifx\cals@borderB\relax     % Bottom border switch (off-on)
\def\cals@borderB{0pt}
\else \let\cals@borderB\relax\fi}

% R1B1
\thead{%
\brow
    \gray\alignC\cell{1}\gray
    \alignL\cell{2}
    \gray\alignC\cell{3}\gray
\erow
}
%R2B2
\brow
    \gray\alignC\cell{\vfil one}\gray
    \alignL\cell{\vfil two}
    \gray\alignC\cell{\vfil three}\gray
\erow
%R3B3
\brow
    \gray\bb\alignC\cell{\vfil one}\bb\gray
    \alignL\cell{\vfil two}
    \gray\alignC\cell{\vfil three}\gray
\erow
%R4B4
\brow
    \gray\alignC\cell{\vfil one}\gray
    \alignL\cell{\vfil two}
    \gray\alignC\cell{\vfil three}\gray
\erow
%R4B4
\brow
    \gray\alignC\cell{\vfil un}\gray
    \alignL\cell{\vfil deux}
    \gray\alignC\cell{\vfil trois}\gray
\erow
\makeatletter
\end{calstable}\par
  \caption{caption}
\end{table*}
\end{document}

Answer 3

The environment {NiceTabular} of nicematrix provides tools to color cells, rows and columns in a way compatible with the horizontal rules of booktabs.

\documentclass[a5paper]{article}
\usepackage{xcolor}
\usepackage{booktabs,nicematrix}
\usepackage{lipsum}

\begin{document}

\pagestyle{empty}


\lipsum[1]

\begin{table*}[!htb]
  \centering
  \begin{NiceTabular}[width=4cm,colortbl-like]{>{\columncolor{gray}}cX>{\columncolor{gray}}c}
    \toprule
    1&2&3\\
    \midrule
    one&two&three\\
    one&two&three\\
    \cmidrule{2-3}
    one&two&three\\
    \midrule
    un&deux&trois\\
    \bottomrule
  \end{NiceTabular}
  \caption{caption}
\end{table*}

\end{document}

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