Horizontal lines cross the left side of table in right to left context (lualatex)

[seloumi]

In this example I'm trying to test tblr tabular in an RTL context with babel (lualatex engine)

\documentclass{article}
\usepackage[bidi=basic,arabic,provide=*]{babel}
\usepackage{tabularray}

\begin{document}

\begin{tblr}{|c|}
\hline
one\\
\hline 
\end{tblr}

\end{document}

The output appears fine, but if you take a great zoom the following defect can be seen ( horizontal lines cross the left side of the table )

Without babel (same issue)

\documentclass{article}

\usepackage{tabularray}

\textdir TRT
\begin{document}

\begin{tblr}{|c|}
\hline
one\\
\hline 
\end{tblr}

\end{document}

shifted-hlines-in-tblr-tabular-in-rtl-context

[seloumi]

With double vrule the defect becomes greater

\documentclass{article}
\usepackage{tabularray}

\textdir TRT
\begin{document}

\begin{tblr}{|c||}
\hline
one \\
\hline 
\end{tblr}

\end{document}

[lvjr]

Sorry, I know little about RTL typesetting. Any help would be appreciated.

[seloumi]

Maybe this helps a little https://tex.stackexchange.com/a/351558/54817

[lvjr]

It is not that easy to understand well all of \pagedir, \bodydir, \pardir, \textdir, \linedir, \mathdir and \boxdir. But the following test shows that the problem is from hlines.

\documentclass{article}

\usepackage{showframe}
\renewcommand*\ShowFrameColor{\color{blue}}

\usepackage{tabularray}
\setlength\parindent{0pt}

\begin{document}

Hello

\begin{tblr}{|c|}
\hline
one\\
\hline
\end{tblr}

Hello

\begin{tblr}{|c||}
\hline
one \\
\hline
\end{tblr}

\textdir TRT

Hello

\begin{tblr}{|c|}
\hline
one\\
\hline
\end{tblr}

Hello

\begin{tblr}{|c||}
\hline
one \\
\hline
\end{tblr}

\end{document}

[seloumi]

What matters here is just \textdir , to add tblr tabular in right to left context we have two options

• First: we can insert tabular in left to right group with \textdir TLT then changing text direction for every cell with cells={cmd={\textdir TRT}}, in this cas order of columns is from left to right and this is not desirable

• Second: tabular is inserted in right to left context in this cas order of columns is fine and text inside cells is from right to left It just remains the problem of shifted hlines

\documentclass{article}

\usepackage{showframe}
\renewcommand*\ShowFrameColor{\color{blue}}

\usepackage{tabularray}
\setlength\parindent{0pt}

\begin{document}

\begin{tblr}{|c|c||}
\hline
one & two\\
\hline 
\end{tblr}

\textdir TRT

{\textdir TLT
\begin{tblr}{colspec={|c|c||},cells={cmd={\textdir TRT}}}
    \hline
    one & two\\
    \hline 
\end{tblr}}% columns are from left to right

\begin{tblr}{|c|c||}
    \hline
    one & two\\
    \hline 
\end{tblr} % columns are from right to left

\end{document}

[seloumi]

Here a typical example of what a table looks like in right to left context with babel package

\documentclass{article}

\usepackage{showframe}
\renewcommand*\ShowFrameColor{\color{blue}}

\usepackage{tabularray}
\setlength\parindent{0pt}

\usepackage[bidi=basic,arabic,provide=*,layout=tabular]{babel}

\begin{document}


\babeladjust{bidi.text=off}

\begin{tabular}{|c|c||}
\hline
one & two\\
\hline 
\end{tabular}

\end{document}

[lvjr]

Adding \mathdir TRT solves the problem. It is probably because tabularray uses math \vcenter to do vertically-centered alignment (it is the same in tabular).

\documentclass{article}

\usepackage{showframe}
\renewcommand*\ShowFrameColor{\color{blue}}

\usepackage{tabularray}
\setlength\parindent{0pt}

\begin{document}

Hello\par
\begin{tblr}{|c||c|||}
\hline
one & two \\
\hline
\end{tblr}

\textdir TRT \mathdir TRT

Hello\par
\begin{tblr}{|c||c|||}
\hline
one & two \\
\hline
\end{tblr}

\end{document}

[seloumi]

In right to left context math should be LTR so with your example we need to change math direction for every cell

[lvjr]

The good news is that \textvcenter is coming to LaTeX kernel. See

latex3/latex2e@ea018ca

Hopefully in the near future we won't need the above fix any more.

[seloumi]

Thank you very much for guidances and for the great package, waiting for the command \textvcenter to come out

I've added this code in the preamble to make modifications general without having to add them for each tblr environment

What do you think? is there a better way?

\documentclass{article}

\usepackage{showframe}
\renewcommand*\ShowFrameColor{\color{blue}}

\usepackage{tabularray}
\setlength\parindent{0pt}

\AddToHook{env/tblr/begin}{%
\ifnum\textdirection=0\else \mathdir TRT\fi
}

\SetTblrInner[tblr,longtblr]{cells={cmd={\mathdir TLT}}}

\begin{document}

Hello\par
\begin{tblr}{|c||c|||}
\hline
one & two \\
\hline
\end{tblr}

\textdir TRT 

Hello\par
\begin{tblr}{|c||c|||}
\hline
one & two $ax+b$\\
\hline
\end{tblr}

$ax+b$

\end{document}

[lvjr]

I think it is good.