I am writing an environment to format its content in a box with a background and that can be split across pages. I am using a splitting algorithm similar to the one used in the boites package.
I want to fill the background (and also do other things, like draw a frame with rounded corners) using tikz. But some unwanted vertical spacing are being inserted between some lines. This spacing does not appear when I use \colorbox to fill the background.
Here is a minimal working example that shows the problem:
\documentclass{article}
\usepackage[paperwidth=140mm,paperheight=55mm,margin=5mm]{geometry}
\usepackage{tikz}
\usepackage{multicol}
\pagestyle{plain}
\makeatletter
% The purpose of the `brbox` environment below is to typeset a box with
% a given background colour. The box may be split by page breaks.
%
% The algorithm used is similar to the one found in the `boites`
% package:
%
% - first the text is formatted in a vbox
%
% - then each line of the vbox is extracted from the vbox and output in
% a colorbox.
\newbox\boxhead
\newbox\boxtail
\newbox\boxtemp
\newdimen\dimtemp
\newif\ifbrbox@continue
% split \boxtail between the first line (to be stored in \boxhead) and
% the rest (to be stored in \boxtail);
\def\@boxsplit{%
% total height (height + depth) of original box
\dimtemp\ht\boxtail
\advance\dimtemp\dp\boxtail
% split original box in order to retrieve its first line
\setbox\boxhead\vsplit\boxtail to \z@
% the height and depth of the first box are zero: fix them
\setbox\boxhead\vbox{\unvbox\boxhead}%
\wd\boxhead\linewidth%?????????????????????????????????????????????????
\ifvoid\boxtail
\else
% the gap (interline space) between first line and the rest has been
% lost; restore original size: the difference of the original total
% height and the total height of each box
\setbox\boxtemp\vbox{\copy\boxhead\copy\boxtail}%
\advance\dimtemp-\ht\boxtemp
\advance\dimtemp-\dp\boxtemp
\advance\dimtemp\dp\boxhead
\dp\boxhead\dimtemp
\fi
}
% add \fboxsep to the last line
\def\brbox@addfsepdp{%
\dimtemp\dp\boxhead
\advance\dimtemp\fboxsep
\dp\boxhead\dimtemp
}
\newenvironment{brbox}{%
\setbox\boxtail\vbox\bgroup
}{%
\egroup
{%
\noindent
\splittopskip\z@ % glue inserted at the top of a box resulting from a \vsplit
\baselineskip\z@
\lineskiplimit\z@
\lineskip\z@
\vfuzz\maxdimen
\@boxsplit
\setbox\boxhead\vbox{\vskip\fboxsep\box\boxhead}% add \fboxsep to the first line
\leavevmode
\ifvoid\boxtail
\brbox@addfsepdp % add \fboxsep to the last line
\brbox@singleline
\else
\brbox@firstline
\hfil
\brbox@continuetrue
\loop
\@boxsplit
\leavevmode
\ifvoid\boxtail
\brbox@addfsepdp % add \fboxsep to the last line
\brbox@lastline
\brbox@continuefalse
\else
\brbox@middleline
\hfil
\fi
\ifbrbox@continue\repeat
\fi
}%
}
\def\brbox@tikzline{\tikz\node[inner xsep=0pt,inner ysep=0pt,fill=yellow!30](p){\copy\boxhead};}
\def\tikzlines{%
\let\brbox@singleline \brbox@tikzline
\let\brbox@firstline \brbox@tikzline
\let\brbox@middleline \brbox@tikzline
\let\brbox@lastline \brbox@tikzline
}
\tikzlines
% alternative: use colorbox to fill the background of the box
\def\brbox@bgline{{\fboxsep\z@ \colorbox{yellow!35}{\box\boxhead}}}
\def\bglines{%
\let\brbox@singleline \brbox@bgline
\let\brbox@firstline \brbox@bgline
\let\brbox@middleline \brbox@bgline
\let\brbox@lastline \brbox@bgline
}
\makeatother
\newcommand{\mytext}{%
\LaTeX\ is a high-quality typesetting system; it includes features
designed for the production of technical and scientific
documentation.
\LaTeX\ is the de facto standard for the communication and publication
of scientific documents.
}
\begin{document}
\begin{multicols}{3}
\mytext
\columnbreak
\begin{brbox} \mytext \end{brbox}
\columnbreak
\bglines
\begin{brbox} \mytext \end{brbox}
\end{multicols}
\end{document}
How can I eliminate the extra vertical spacing that appears only when tikz is used?
This looks like a tikz bug.
tcolorboxormdframedyou can also format framed boxes with page breaks? Here you have an example – Ignasi Nov 15 '13 at 11:21beamerclass. It also does not work with nested boxes. The algorithm I am implementing does not have such limitations. – Romildo Nov 15 '13 at 11:55