Rule before one new section

Question

I use rule so as to separate the differents sections. I would like to automate this so as to use the following syntax :

\section*{One day}

\noindent\lipsum[1]

\section*{Another day}

\noindent\lipsum[1]

\section*{One more day}

\noindent\lipsum[1]

\newpage
\section*{One last day}

\noindent\lipsum[1]

There are two problems to solve :

1. The first section isn't preceded by a rule.
2. If one section is at the begining of one new page, it isn't preceded by a rule.

Code to ameliorate

\documentclass[12pt]{article}
    \newcommand{\myRule}{%
        \vspace{0.5cm}\hrule%
    }

    \usepackage{lipsum}


\begin{document}

% No rule ! 
\section*{One day}

\noindent\lipsum[1]

\myRule
\section*{Another day}

\noindent\lipsum[1]

\myRule
\section*{One more day}

\noindent\lipsum[1]

\newpage
% No rule !
\section*{One last day}

\noindent\lipsum[1]

\end{document}

Answer 1

By combining Mico's and Alan Munn's answer, here's a simpler code that should accomplish what's requested:

\usepackage{titlesec}
\titleformat{\section}
  {\leaders\vrule width \textwidth\vskip 0.4pt\vspace{.8ex}%
   \normalfont\Large\bfseries}
  {}
  {0em}
  {}

The space between the rule and the section title is .8ex (adjust to suit you).

Answer 2

The following code is based on this posting to comp.text.tex in May 2011. No rule will be drawn if the section header is at the top of a page, including the very first page. This method works with both numbered and unnumbered section headers.

The amount of space between the end of a section and the subsequent rule and between the rule and the next section header, is controlled by the commands \vspace{2\bigskipamount} and \vspace{\smallskipamount}; change the arguments of the two \vspace commands to suit your preferences. The width of the rule by default is 0.4pt. (0.4pt seems to be something of a standard width for many lines in LaTeX...) You can change this setting too, of course.

Note that the command \separatorrule can be used on its own anywhere in the text, not just right before a section heading. Its two main distinguishing properties are (i) no rule will be drawn at the top of a page and (ii) no rule will be drawn later on in a page if the command is followed by an implicit or explicit \clearpage command, or similar-effect command such as \cleardoublepage.

\documentclass{article}
\newcommand{\separatorrule}{% 
    \par\vspace{2\bigskipamount}
    \leaders\vrule width \textwidth\vskip 0.4pt 
    \vspace{\smallskipamount}\nointerlineskip}    
\let\origsection\section
\renewcommand\section{\separatorrule \origsection}
\usepackage{lipsum} % for filler text

\begin{document}
\section*{A} \lipsum[1]
\section{B}  \lipsum[2]
\section*{C} \lipsum[3]
\clearpage
\section*{D} \lipsum[4]
\section{E}  \lipsum[5]
\end{document}

Finally, I have a strong hunch that the provider of the code for the separator rule in the comp.text.tex group, "Enrico Gregorio", is the very same person as egreg in the TeX Stack Exchange group. At any rate, the originality of my contribution to this posting is clearly minimal.

Answer 3

This is only a partial answer, since there are still some spacing issues that need to be resolved. At the very least, it could guide to a better solution.

Using a combination of titlesec and some code from needspace it is possible to condition on page availability.

\documentclass[12pt]{article}
\usepackage{lipsum}% http://ctan.org/pkg/lipsum
\usepackage{etoolbox}% http://ctan.org/pkg/etoolbox
\usepackage{titlesec}% http://ctan.org/pkg/titlesec
\newcounter{tmpcntr} \preto\newpage{\setcounter{tmpcntr}{0}}%

% Taken from the needspace package (http://ctan.org/pkg/needspace)
\makeatletter
\newcommand{\needspace}[3]{\par \penalty-100\begingroup
  \setlength{\dimen@}{#1}%
  \dimen@ii\pagegoal \advance\dimen@ii-\pagetotal
  \ifdim \dimen@>\dimen@ii
    #3
  \else
    #2
  \fi\endgroup}
\makeatother

\titleformat{\section}{\bfseries\large\stepcounter{tmpcntr}}{\thesection}{\quad}{%
  \needspace{\dimexpr0.4pt+5mm+1.5\baselineskip\relax}%
    {\ifnumequal{\value{tmpcntr}}{1}{}{\titlerule\nobreak\kern5mm\nobreak}}% enough space
    {\break\vspace*{\topskip}}% not enough space
}

\begin{document}

% No rule ! 
\section*{One day}

\noindent\lipsum[1]

\section*{Another day}

\noindent\lipsum[1]

\section*{One more day}

\noindent\lipsum[1]

\newpage
% No rule !
\section*{One last day}

\noindent\lipsum[1]

\end{document}
​

The modified code from needspace provides

\needspace{<len>}{<less than len>}{<more than len>}

which executes <less than len> if there is less than <len> available on the page, otherwise it issues <more than len>.

Additionally, the tmpcntr counter is meant to be a reference of whether or not you start a new page, or the start of your document with a \section. If this counter is 1 (incremented within \section) no \titlerule is typeset.

Answer 4

Here's a partial answer using the titlesec package. I've added a conditional to remove the rule for the first section. If this applied to chapters, you'll need to add \ruledfalse to the definition of \chapter. This doesn't solve the top of page problem, however, but I'll leave it up as an answer, since others who arrive here may not have that requirement.

\documentclass{article}
\usepackage{titlesec}
\newif\ifruled
\titleformat{\section}
    {\ifruled\titlerule\else\global\ruledtrue\fi\vspace{.8ex}%
     \normalfont\bfseries} {}{0em}{}

\begin{document}
\section*{A section}
\section*{Another section}
\end{document}