Rule in textarea every n points

Question

I am currently developing a new layout. This must be typeset on a grid, and every line starts at a multiple of 13bp from the top of the text area. To help me check, I'd like to have rules every 13bp from the top of that area on every page without interfering with the typeset text. This is similar to my previous question A package to help with layout generation? Graph paper in the background? where I asked about a grid, but in difference to that question, the grid should start at the top (left) of the text area, not the page.

As far as I see the eso-pic solution is not possible here. What else can I do?

(I am using PDFTeX on Mac and Windows)

Answer 1

The following solution is independent from the output routine and uses a eso-pic like approach:

\documentclass[11pt]{article}
\usepackage{lipsum}
% \usepackage[showframe]{geometry}

\usepackage{atbegshi,picture}
\makeatletter
\AtBeginShipout{%
  \AtBeginShipoutUpperLeft{%
    \put(\dimexpr
      \ifodd\value{page}\oddsidemargin\else\evensidemargin\fi + 1in\relax,
      -\dimexpr\topmargin + 1in + \headheight + \headsep\relax){%
      \begin{picture}(0,0)%
        \setlength{\unitlength}{13bp}%
        \setlength{\dimen0 }{0pt}%
        \@whiledim\dimen0<\dimexpr\textheight+1sp\relax\do{%
          \put(0,-\dimen0){\line(1,0){\textwidth}}%
          \addtolength{\dimen0 }{\unitlength}%
        }%
      \end{picture}%
    }%
  }%
}
\makeatother

\makeatletter
\setlength{\topskip}{13bp}
\renewcommand\normalsize{%
   % \baselineskip to 13bp for \normalsize
   \@setfontsize\normalsize\@xipt{13bp}%
   % the following values are taken from size11.clo.
   \abovedisplayskip 11\p@ \@plus3\p@ \@minus6\p@
   \abovedisplayshortskip \z@ \@plus3\p@
   \belowdisplayshortskip 6.5\p@ \@plus3.5\p@ \@minus3\p@
   \belowdisplayskip \abovedisplayskip
   \let\@listi\@listI
}
% \parskip without glue:
% \setlength{\parskip}{0pt}
% or with positive \parskip:
\usepackage{parskip}
\setlength{\parskip}{13bp}
\makeatother

\begin{document}
\lipsum[1-3]
\end{document}

Answer 2

Something like this (I also changed baselineskip and parskip to the grid)

\documentclass{article}

\makeatletter
\renewcommand\normalsize{%
   \@setfontsize\normalsize\@xpt{13bp}
   \abovedisplayskip 10\p@ \@plus2\p@ \@minus5\p@
   \abovedisplayshortskip \z@ \@plus3\p@
   \belowdisplayshortskip 6\p@ \@plus3\p@ \@minus3\p@
   \belowdisplayskip \abovedisplayskip
   \let\@listi\@listI}
\normalsize
\setlength\parskip{13bp}

\def\@oddhead{%
\setlength\unitlength{13bp}
\raisebox{-\topskip}{\begin{picture}(0,0)%
\multiput(0,0)(0,-1){40}{\line(1,0){30}}%
\end{picture}}\hfill}
\makeatother

\def\a{One two three four five. }
\def\b{\a\a Red green blue. \a\a}
\def\c{\b\b Black white. \b\a\b}


\begin{document}

\c

\c

\c

\end{document}

Answer 3

That are simple lines, can also be done with \rule, package pict2e or something similiar.

\documentclass{article}
\usepackage{pstricks,multido}

\begin{document}
\setlength\baselineskip{13bp}\noindent%
\multido{\iA=0+13}{45}{\psline[linecolor=gray](0,-\iA bp)(\linewidth,-\iA bp)}%
%
foo\\
bar\\
baz\\
foobar\\
foobarbaz

\end{document}

and the same with \rule

\documentclass{article}
\usepackage{multido}
\begin{document}
\makeatletter%
\newdimen\tempL%
\setlength\baselineskip{13bp}\noindent%
\makebox(0,0)[t]{\multido{\iA=0+13}{40}{%
\put(0,-\strip@pt\tempL){\rule{\linewidth}{0.5pt}}%
\advance\tempL by 13bp}}
\makeatother%
%
foo\\
bar\\
baz\\
foobar\\
foobarbaz

\end{document}