long tables: customization of rule width/thickness

[DAbidou]

For long tables, it would be great if I could make the width/thickness of the rules encompassing the first header different from those of the repeated headers. Also, the same is desired for the repeated footers and last footer.

[lvjr]

You can create your special tabularray environment and add extra rules to first head and last foot:

\documentclass{article}

\usepackage[paperwidth=8cm,paperheight=6cm,width=7cm,height=5cm]{geometry}
\usepackage{tabularray,xcolor}
\UseTblrLibrary{booktabs}

\begin{document}

\DefTblrTemplate{firsthead}{mytemplate}{
  \UseTblrTemplate{caption}{default}
  \vskip 6pt
  \hrule height 1pt
}

\DefTblrTemplate{middlehead,lasthead}{mytemplate}{
  \UseTblrTemplate{capcont}{default}
  \vskip 6pt
}

\DefTblrTemplate{firstfoot,middlefoot}{mytemplate}{
  \vskip 6pt
  \UseTblrTemplate{contfoot}{default}
}

\DefTblrTemplate{lastfoot}{mytemplate}{
  \hrule height 1pt width \tablewidth
  \vskip 6pt
  \UseTblrTemplate{note}{default}
  \UseTblrTemplate{remark}{default}
}

\NewTblrTheme{mytheme}{
  \SetTblrTemplate{head,foot}{mytemplate}
}

\NewTblrEnviron{mytblr}
\SetTblrOuter[mytblr]{long,headsep=0pt,footsep=0pt,theme=mytheme}

\begin{mytblr}[
  caption = {The Caption},
]{
  colspec = {XX}, rowhead = 1,
  row{even} = {gray!30}, row{1} = {blue!15},
}
\toprule[1.5pt]
  One & Two  \\
\midrule
   1  &   2  \\
   3  &   4  \\
   5  &   6  \\
   7  &   8  \\
   9  &  10  \\
  11  &  12  \\
  13  &  14  \\
  15  &  16  \\
  17  &  18  \\
  19  &  20  \\
\bottomrule[1.5pt]
\end{mytblr}

\end{document}

[jasperhabicht]

This solution does not quite work if no lines are printed at the top and bottom of middle parts of the table and hlines happen to sit at page breaks. Consider the following example where the line at the bottom of the middle part on page 2 and the line at the top of the middle part on page 3 are missing (also see question at TeX.SX; probably related to issue 130):

\documentclass{article}
\usepackage[
    paperwidth=8.5cm, 
    paperheight=5.5cm, 
    width=7.5cm, 
    height=4.5cm]{geometry}
\usepackage{tabularray}

\begin{document}

\DefTblrTemplate{firsthead}{mytemplate}{
  \UseTblrTemplate{caption}{default}
  \vskip 6pt 
  \hrule height 2pt width \tablewidth
  \vskip -6pt 
}

\DefTblrTemplate{lastfoot}{mytemplate}{
  \vskip -2pt 
  \hrule height 2pt width \tablewidth
}

\NewTblrTheme{mytheme}{
  \SetTblrTemplate{firsthead}{mytemplate}
  \SetTblrTemplate{lastfoot}{mytemplate}
}

\begin{longtblr}[
  halign = c,
  caption = {Long Caption},
  label = {tblr:test},
  theme = mytheme,
]{
  colspec = {@{}XXXX@{}},
  hline{3,5,7,9,11} = {1pt},
}
  1 & A & B & C \\
  2 & A & B & C \\
  3 & A & B & C \\
  4 & A & B & C \\
  5 & A & B & C \\
  6 & A & B & C \\
  7 & A & B & C \\
  8 & A & B & C \\
  9 & A & B & C \\
  10 & A & B & C \\ 
  11 & A & B & C \\
  12 & A & B & C \\
\end{longtblr}

\end{document}

[muzimuzhi]

A patch to \__tblr_build_page_table:nnn (interaction with rowhead and rowfoot are not handled):

Full example, new inner options `first hlines` and `last hlines`

\documentclass{article}
\usepackage[
    paperwidth=8.5cm, 
    paperheight=5.5cm, 
    width=7.5cm, 
    height=4.5cm]{geometry}
\usepackage{tabularray}

\ExplSyntaxOn
\bool_new:N \l__tblr_page_table_use_first_hlines_bool
\bool_new:N \l__tblr_page_table_use_last_hlines_bool

\cs_gset_protected:Npn \__tblr_build_page_table:nnn #1 #2 #3
  {
    \__tblr_build_one_table:nnNN {#2} {#3}
      \l__tblr_page_table_use_first_hlines_bool % replaces \c_false_bool
      \l__tblr_page_table_use_last_hlines_bool  % replaces \c_false_bool
    \vbox_set:Nn \l__tblr_table_box
      {
        \box_use:N \l__tblr_table_head_box
        \__tblr_cover_two_vboxes:NN \l__tblr_row_head_box \l__tblr_table_box
        \box_use:N \l__tblr_row_foot_box
        \hrule height ~ 0pt
        \box_use:N \l__tblr_table_foot_box
      }
    \__tblr_halign_whole:Nn \l__tblr_table_box {#1}
  }

% new keys `first/last hlines`
\keys_define:nn { tblr }
  {
    first~ hlines .bool_set:N = \l__tblr_page_table_use_first_hlines_bool,
    last~ hlines  .bool_set:N = \l__tblr_page_table_use_last_hlines_bool
  }
\clist_gput_right:Nn \g__tblr_table_known_keys_clist
  { first~ hlines, last~ hlines }
\ExplSyntaxOff

\begin{document}

\DefTblrTemplate{firsthead}{mytemplate}{
  \UseTblrTemplate{caption}{default}
  \vskip 6pt 
  \hrule height 2pt width \tablewidth
  \vskip -6pt 
}

\DefTblrTemplate{lastfoot}{mytemplate}{
  \vskip -2pt 
  \hrule height 2pt width \tablewidth
}

\NewTblrTheme{mytheme}{
  \SetTblrTemplate{firsthead}{mytemplate}
  \SetTblrTemplate{lastfoot}{mytemplate}
}

\begin{longtblr}[
  halign = c,
  caption = {Long Caption},
  label = {tblr:test},
  theme = mytheme
]{
  colspec = {@{}XXXX@{}},
  hline{3,5,7,9,11} = {1pt},
  first hlines,
  last hlines
}
  1 & A & B & C \\
  2 & A & B & C \\
  3 & A & B & C \\
  4 & A & B & C \\
  5 & A & B & C \\
  6 & A & B & C \\
  7 & A & B & C \\
  8 & A & B & C \\
  9 & A & B & C \\
  10 & A & B & C \\ 
  11 & A & B & C \\
  12 & A & B & C \\
\end{longtblr}

\end{document}

Full example v2, checked with tabularray 2025B (2025-08-29), options renamed to repeat-first-hlines and repeat-last-hlines

\documentclass{article}
\usepackage[
    paperwidth=8.5cm,
    paperheight=5.5cm,
    width=7.5cm,
    height=4.5cm]{geometry}
\usepackage{tabularray}

\usepackage{xpatch}

% checked with tabularray 2025B (2025-08-29)
\ExplSyntaxOn
\bool_new:N \l__tblr_page_repeat_first_hlines_bool
\bool_new:N \l__tblr_page_repeat_last_hlines_bool

% restore catcode of space character. It's needed by the explicit space
% character used in \__tblr_build_page_table:nnn, "\hrule height ~ 0pt"
\char_set_catcode_space:N \
\xpatchcmd \__tblr_build_page_table:nnn
  {%
    \__tblr_build_one_table:nnNN {#2}{#3}\c_false_bool \c_false_bool
  }
  {%
    \__tblr_build_one_table:nnNN {#2}{#3}%
      \l__tblr_page_repeat_first_hlines_bool
      \l__tblr_page_repeat_last_hlines_bool
  }
  {}{\PatchFailed}
\char_set_catcode_ignore:N \

% new inner keys "repeat-first-hlines" and "repeat-last-hlines"
\keys_define:nn { tabularray/table/inner }
  {
    repeat-first-hlines .bool_set:N = \l__tblr_page_repeat_first_hlines_bool,
    repeat-last-hlines  .bool_set:N = \l__tblr_page_repeat_last_hlines_bool
  }
\ExplSyntaxOff

\begin{document}

\DefTblrTemplate{firsthead}{mytemplate}{
  \UseTblrTemplate{caption}{default}
  \vskip 6pt
  \hrule height 2pt width \tablewidth
  \vskip -6pt
}

\DefTblrTemplate{lastfoot}{mytemplate}{
  \vskip -2pt
  \hrule height 2pt width \tablewidth
}

\NewTblrTheme{mytheme}{
  \SetTblrTemplate{firsthead}{mytemplate}
  \SetTblrTemplate{lastfoot}{mytemplate}
}

\begin{longtblr}[
  halign = c,
  caption = {Long Caption},
  label = {tblr:test},
  theme = mytheme
]{
  colspec = {@{}XXXX@{}},
  hline{3,5,7,9,11} = {1pt},
  repeat-first-hlines,
  repeat-last-hlines
}
  1 & A & B & C \\
  2 & A & B & C \\
  3 & A & B & C \\
  4 & A & B & C \\
  5 & A & B & C \\
  6 & A & B & C \\
  7 & A & B & C \\
  8 & A & B & C \\
  9 & A & B & C \\
  10 & A & B & C \\
  11 & A & B & C \\
  12 & A & B & C \\
\end{longtblr}

\end{document}

[jasperhabicht]

Nice! This would really be an improvement to the package I think! It is actually not too much code, but to me it was difficult to figure out a solution. Thank you! Maybe you could add this answer to the TeX.SX question as well.

[ScumCoder]

@muzimuzhi you are a magician and a savior.

The only thing that separates your code from perfection is that it does not work with hlines option; the line at page breaks is repeated whether first hlines/last hlines are enabled or not.

I tried to cheat by replacing hlines with cell{1-Z}{1} = {cmd=\hline}, but got a bunch of You can't use '\hrule' here except with leaders errors. Looks like I'll have to manually insert \hlines everywhere (which is one of the reasons I decided to migrate from longtable to tabularray in the first place). Oh well.

[ScumCoder]

@muzimuzhi OK, I think I found the root of the problem.
The issue with longtblr's hlines is twofold:

1. the package suppresses the typesetting of hlines that sit at page breaks;
2. the package places copies of the hline defined for the top of the very first row and the hline defined for the bottom of the very last row.

Your patch addresses the first issue. Would it be too much to ask you to make a patch that would address the second one too?

[botanikus]

Hi there! Has there been an update on this so far?

[lenoleno]

Coming from #615. Following the discussion here, I have managed to put a (non-repeating) horizontal line into lastfoot. But now I'm facing the other problem mentioned by @ScumCoder:

the package suppresses the typesetting of hlines that sit at page breaks;

Unfortunately, tabularray 2025A seems to break @muzimuzhi's patch. Any idea how to revive that patch?

[muzimuzhi]

Unfortunately, tabularray 2025A seems to break @muzimuzhi's patch. Any idea how to revive that patch?

Patch updated for tabularray 2025A.

[lenoleno]

Thanks! Seems to work fine so far.

One note, since the patch is about keeping regular horizontal lines at page breaks, at least for the repeat-last-hlines option, I think a name like keep-bottom-hlines would be more self-explanatory. As for the repeat-first-hlines option, that one is not required in my use-case, and I really have no idea how hlines at page breaks might interfere with rules above the header. So I cannot comment on that option name, currently. Thanks, again!