How do I fill table cells with a background color?

Question

I'd like to fill the cells of a table with a background color. How can this be done?

Answer 1

The xcolor provides support for coloring table rows in a variety of patterns. The colortbl can color rows, columns, cells and rules.

There is a nice article by Lapo Filippo Mori in the PracTeX Journal that describes the usage of both packages. Scroll down to section 4.

Answer 2

The package nicematrix provides tools to color background of cells in tabulars. With those tools, you will have a good output in the PDF viewers: the rules won't seem to disappear in those PDF viewers at some levels of zoom (eg Adobe Reader) and you won't see the thin white lines you have in some PDF viewers (eg Sumatra PDF).

First, there are tools with the syntax of colortbl.

\documentclass{article}

\usepackage{nicematrix}

\begin{document}

\begin{NiceTabular}{ccc>{\columncolor{blue!15}}c}[hvlines,colortbl-like]
\rowcolor{red!15}1 & 22 & 34 & 2346 \\
2346 & 2 & 246  & 2 \\
1 & 34 & 2346111 & 1 \\
\cellcolor{yellow!50}1222 & 0 & 34 & 463
\end{NiceTabular}

\end{document}

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

If you prefer to have the formatting instructions outside the main array, it's also possible with instructions in the \CodeBefore.

 \documentclass{article}

 \usepackage{nicematrix}

 \begin{document}

 \begin{NiceTabular}{cccc}[hvlines,colortbl-like]
 \CodeBefore
   \columncolor{blue!15}{3}
   \rowcolor{red!15}{1}
   \cellcolor{yellow!50}{4-1}
 \Body
 1 & 22 & 34 & 2346 \\
 2346 & 2 & 246  & 2 \\
 1 & 34 & 2346111 & 1 \\
 1222 & 0 & 34 & 463
 \end{NiceTabular}

 \end{document}

There is also a command \Block (initially designed to merge cells) which may be used to color zones in the array.

\documentclass{article}
\usepackage{nicematrix}

\begin{document}

\begin{NiceTabular}{cccc}
\Block[fill=red!15,rounded-corners]{1-*}{}1 & 22 & 34 & 2346 \\
2346 & 2 & 246  & 2 \\
\Block[fill=yellow!50,rounded-corners]{2-2}{0} & & 2346111 & 1 \\
& & 34 & 463
\end{NiceTabular}

\end{document}

Eventually, if you have something special to draw, you may use Tikz and the PGF/Tikz nodes created by nicematrix under the array.

\documentclass{article}
\usepackage{nicematrix,tikz}

\begin{document}

\begin{NiceTabular}{cccc}
\CodeBefore
  \tikz \fill [red!15] (1-|1) -- (5-|3) -- (1-|4) -- cycle ;
\Body
1 & 22 & 34 & 2346 \\
2346 & 2 & 246  & 2 \\
1 & 34 & 2346111 & 1 \\
1222 & 0 & 34 & 463
\end{NiceTabular}

\end{document}