Skip double marks on chapter pages

Question

Here is a little example to illustrate my problem:

\documentclass[fontsize=12pt, paper=a4]{scrreprt} 
\usepackage[ngerman]{babel}
\usepackage{blindtext}
\usepackage{scrpage2} 

\clearscrheadfoot 
\pagestyle{scrheadings} 
\ihead{\leftmark} 
\ohead{\rightmark} 
\cfoot{\pagemark} 

\automark[subsection]{chapter} 

\begin{document} 

\chapter{Test}
\Blindtext

\section{Sec}
\Blindtext

\subsection{SubSec}
\Blindtext

\chapter{Test2}
\Blindtext

\section{Sec2}
\Blindtext

\subsection{SubSec2}
\Blindtext
\end{document}

As you can see I would like to have chapter and subsection in the heading of each page. But on pages 2 and 6, where no subsection is available, the chapter appears twice in the head. On pages 3, 4, 7 and 8 everything is OK.

I would like to suppress the \rightmark for the subsection, when there is no subsection available. How can I do this?

Answer 1

You can make the right hand heading text conditional on it not being the same as the left:

\ohead{%
\expandafter\def\expandafter\tmpa\expandafter{\romannumeral`\Q\leftmark}%
\expandafter\def\expandafter\tmpb\expandafter{\romannumeral`\Q\rightmark}%
\ifx\tmpa\tmpb\else\rightmark\fi
} 

Answer 2

I think it makes more sense to have the section in the header instead of nothing without having a subsection. The following example uses the first section or subsection element on the page for the header. It uses an additional marks register from e-TeX.

\documentclass[fontsize=12pt, paper=a4]{scrreprt}
\usepackage[ngerman]{babel}
\usepackage{blindtext}
\usepackage{scrpage2}
\usepackage{etex}

\clearscrheadfoot
\pagestyle{scrheadings}
\ihead{\leftmark}
% \ohead{\rightmark}
\iftrue % oneside
  \ohead{\firstmarks\subsectionmarks}
\else % twoside
  \lohead{\firstmarks\subsectionmarks}
  \rohead{\botmarks\subsectionmarks}
\fi
\cfoot{\pagemark}

\automark[subsection]{chapter}

\makeatletter
\newmarks\subsectionmarks
\newcommand*{\marksubsec}[1]{%
  \begingroup
    \protected@edef\@temp{%
      \marks\subsectionmarks{#1}%
    }%
    \@temp
  \endgroup
}
\@ifdefinable\org@chaptermark{%
  \let\org@chaptermark\chaptermark
  \renewcommand*{\chaptermark}{%
    \marks\subsectionmarks{}
    \org@chaptermark
  }%
}
% Redefining \sectionmark
\@ifdefinable{\org@sectionmark}{%
  \let\org@sectionmark\sectionmark
  \iftrue
    \renewcommand*{\sectionmark}[1]{%
      \marksubsec{%
        \ifnum\value{secnumdepth}>0 %
          \if@mainmatter
            \sectionmarkformat
          \fi
        \fi
        #1%
      }%
      \org@sectionmark{#1}%
    }
  \else
    \renewcommand*{\sectionmark}[1]{%
      \marksubsec{}%
      \org@sectionmark{#1}%
    }%
  \fi
}
\@ifdefinable\org@subsectionmark{%
  \let\org@subsectionmark\subsectionmark
  \renewcommand*{\subsectionmark}[1]{%  
    \marksubsec{%
      \ifnum\value{secnumdepth}>1 %
        \if@mainmatter
          \subsectionmarkformat
        \fi
      \fi  
      #1%  
    }%   
    \org@subsectionmark{#1}%
  }%
}   
\makeatother

\begin{document}

\chapter{Test}  
\Blindtext

\section{Sec}
\Blindtext   

\subsection{SubSec}
\Blindtext

\chapter{Test2}
\Blindtext

\section{Sec2}
\Blindtext

\subsection{SubSec2}
\Blindtext
\end{document}

• Section headers can be omitted by changing \iftrue to \iffalse after the comment % Redefining \subsectionmark.

• The example assumes oneside setting. For twoside the subsection(/section) header can refer to the first and last subsection(/section) on the page, then change \iftrue to \iffalse for defining the outer header.