# Ordered chaptermarks

To explain my problem let me start with my MWE:

\documentclass[a4paper,10pt]{book}
\usepackage{lipsum}
\usepackage[utf8]{inputenc}
\usepackage{fancyhdr}
\usepackage{extramarks}
\makeatletter
\renewcommand\chapter{\@startsection%
{chapter}{0}{0mm}%
{2.5\baselineskip}{1.5\baselineskip}%
{\centering\normalfont\large\scshape
}%
}
\makeatother
\newcommand{\mychap}[1]{
\chapter*{#1}
\markboth{#1}{#1}}
\renewcommand{\sectionmark}{}
\renewcommand{\chaptermark}{\markboth{\thechapter}}
\pagestyle{fancy}
\fancyhf{}
\fancyhead{}

\fancyhead[LE]{{\thepage}}
\fancyhead[RE]{ {\itshape \nouppercase  \firstleftmark}}%higher level \scshape  \MakeUppercase
\fancyhead[LO]{ {\itshape \nouppercase  \lastrightmark}}
\fancyhead[RO]{ {\thepage}}   %odd page
\begin{document}
\mychap{one}
\lipsum
\mychap{two}
aaa
\mychap{five halves}
\mychap{three}
\lipsum
\mychap{fourth}
\lipsum[5]
\mychap{five}
d
\end{document}


Notice that:

1. I want to treat chapters as sections (no page break, simple title)
2. In the header I want the name of the chapter

I was able to get these features

# BUT

I would like to get also

1. On the header of the odd pages I want the last chapter appearing in the page (this seems to work using \lastrightmark)
2. On the header of the even pages I don't want the first chapter beginning on the page but, the current chapter, i.e. the chapter I'm reading while turning the page.

## In my example

1. On page 2 I would like to have "one" since chapter two begins after the pagebreak between page 1 and page 2;
2. On page 4 I would like to have "four" since chapter five begins after the pagebreak between page 3 and page 4.

How can I get this?

## 1 Answer

You can achieve these headers by setting the \extramarks and using them as follows:

\newcommand{\mychap}[1]{%
\chapter*{#1}%
\markboth{#1}{#1}%
\extramarks{#1}{#1}}

\fancyhead[RE]{\textit{\MakeLowercase{\firstxmark}}}
\fancyhead[LO]{\textit{\MakeLowercase{\lastxmark}}}


So in a document like your sample you get one' in the heading page 2 andfour in the heading of page 4 as you requested.

\documentclass[a4paper,10pt]{book}

\usepackage{lipsum}
\usepackage[utf8]{inputenc}
\usepackage{fancyhdr}
\usepackage{extramarks}

\makeatletter
\renewcommand\chapter{\@startsection%
{chapter}{0}{0mm}%
{2.5\baselineskip}{1.5\baselineskip}%
{\centering\normalfont\large\scshape
}%
}
\makeatother

\newcommand{\mychap}[1]{%
\chapter*{#1}%
\markboth{#1}{#1}%
\extramarks{#1}{#1}}

\pagestyle{fancy}
\fancyhf{}
\fancyhead{}

\fancyhead[LE]{\thepage}
\fancyhead[RE]{\textit{\MakeLowercase{\firstxmark}}}
\fancyhead[LO]{\textit{\MakeLowercase{\lastxmark}}}
\fancyhead[RO]{\thepage}

\begin{document}

\mychap{One}
\lipsum
\mychap{Two}
Two words.
\mychap{Two and a half}
\mychap{Three}
\lipsum
\mychap{Four}
\lipsum[5]
\mychap{Five}
A sentence of five words.
\end{document}


Note that both \markboth and \extramarks are need to get the correct values (which may be reliance on "bug" in extramarks). Also I have use \MakeLowercase` to force the heading text to the desired form as we are now no longer using the standard marks.