tabu package - gaps in vertical lines

Question

I'm in the unfortunate situation that I have to make a table in LaTeX which has thick vertical lines. Since this does not seem to be possible with the default tabular environment, I chose the tabu package. I know that there has been some discussion about its further usability about one year ago, but I found no other possibility, so I decided to give it a try.

It works well for me at all, but there is one horizontal line in my Layout, which is thick only half the way, so the vertical lines end to early for the thin parts, leaving ugly gaps.

This is the Layout:

And this is what I currently got:

Produced by this code:

%Dokumentclass
\documentclass[landscape]{letter}

%Packages
\usepackage[landscape]{geometry}
\usepackage[utf8]     {inputenc}
\usepackage           {multirow}
\usepackage           {tabu}

%Formatting
\pagestyle{empty} %Remove numbering

\begin{document}
  \begin{tabu}{ |[1pt] l | l l | l | l |[1pt] }
                                                                                                                 \tabucline[1 pt]{1-5}
    \multicolumn{2}{ |[1pt] l }{ } & \multicolumn{3}{ |[1pt] l |[1pt]}{ }                                     \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } & \multicolumn{2}{  l |[1pt] }{ }   \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } & \multicolumn{2}{  l |[1pt] }{ }   \\ \tabucline[1 pt]{3-5} \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\ \tabucline[1 pt]{1-5}
  \end{tabu}
\end{document}

Except for the fact, that some resizing has to be done, you can see the gaps in the third row at the first and second column.

I haven't found any solution yet. Is this problem even solvable with tabu? Are there any other packages for this purpose?

Answer 1

One way is to shift up the skip prior to the mid-height \tabucline with a \\[-1pt]. See below for 2nd approach.

%Dokumentclass
\documentclass[landscape]{letter}

%Packages
\usepackage[landscape]{geometry}
\usepackage[utf8]     {inputenc}
\usepackage           {multirow}
\usepackage           {tabu}

%Formatting
\pagestyle{empty} %Remove numbering

\begin{document}
  \begin{tabu}{ |[1pt] l | l l | l | l |[1pt] }
                                                                                                                 \tabucline[1 pt]{1-5}
    \multicolumn{2}{ |[1pt] l }{ } & \multicolumn{3}{ |[1pt] l |[1pt]}{ }                                     \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } & \multicolumn{2}{  l |[1pt] }{ }   \\                       \hline
 y   &                              & \multicolumn{1}{ |[1pt] l |     }{ } & \multicolumn{2}{  l |[1pt] }{ }   \\[-1pt]   \tabucline[1 pt]{3-5} 
\hline
 x   &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\ \tabucline[1 pt]{1-5}
  \end{tabu}
\end{document}

---

Alternately, if you want the thin line to bisect the thick line, then the approach: \\[-1pt] \tabucline[1 pt]{3-5}\\[-12.5pt]\hline works.

%Dokumentclass
\documentclass[landscape]{letter}

%Packages
\usepackage[landscape]{geometry}
\usepackage[utf8]     {inputenc}
\usepackage           {multirow}
\usepackage           {tabu}

%Formatting
\pagestyle{empty} %Remove numbering

\begin{document}
  \begin{tabu}{ |[1pt] l | l l | l | l |[1pt] }
                                                                                                                 \tabucline[1 pt]{1-5}
    \multicolumn{2}{ |[1pt] l }{ } & \multicolumn{3}{ |[1pt] l |[1pt]}{ }                                     \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } & \multicolumn{2}{  l |[1pt] }{ }   \\                       \hline
 y   &                              & \multicolumn{1}{ |[1pt] l |     }{ } & \multicolumn{2}{  l |[1pt] }{ }   \\[-1pt]   \tabucline[1 pt]{3-5}\\[-12.5pt]
\hline
 x   &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\                       \hline
    &                              & \multicolumn{1}{ |[1pt] l |     }{ } &                                 & \\ \tabucline[1 pt]{1-5}
  \end{tabu}
\end{document}

Answer 2

You can do that with {NiceTabular} of nicematrix. With that environment, the key hvlines will draw all the rules excepted in the blocks created by \multicolumn and \Block (that command of nicematrix is not used in this example).

nicematrix creates PGF/Tikz nodes under the cells, rows and columns of the array. It's possible to use those nodes with Tikz to draw whatever rule you want. In the following code, I have drawn the heavy rules with Tikz.

\documentclass{article}

\usepackage{nicematrix,tikz}

\pagestyle{empty}

\begin{document}

\begin{NiceTabular}{lllll}[hvlines]
\Block{1-2}{ } && \Block{1-3}{} \\
    &  &  & \Block{1-2}{} \\ 
 y  &  &  & \Block{1-2}{} \\
 x  &  &  &  & \\
    \\
    \\
    \\
\CodeAfter
\begin{tikzpicture}
\draw [line width = 1pt]
  (1-|1) rectangle (8-|6) 
  (1-|3) -- (8-|3) 
  (4-|3) -- (4-|6) ;
\end{tikzpicture}
\end{NiceTabular}
\end{document}

You need several compilations because the PGF/Tikz nodes are written on the aux file.

It's also possible to draw the thick rules with instructions \Block (using the key draw to draw the frame and line-width to specify the thickness of the rules).

\documentclass{article}
\usepackage{nicematrix}

\pagestyle{empty}

\NewDocumentCommand{\ThickFrame}{}{\Block[transparent,draw,line-width=1pt]}

\begin{document}

\begin{NiceTabular}{lllll}[hvlines]
\ThickFrame{*-2}{}
\Block{1-2}{ } && \ThickFrame{3-*}{}
                  \Block{1-3}{} \\
    &  &  & \Block{1-2}{} & \\ 
 y  &  &  & \Block{1-2}{} \\
 x  &  & \ThickFrame{*-*}{} \\
    \\
    \\
    \\
\end{NiceTabular}
\end{document}

With that technic, you don't use TikZ (even though nicematrix uses PGF, the sublayer of TikZ under the hood).