Breadcrumb hyperlink header

The following example uses the fact that the anchors for the section commands are set and known before the header line is build. That means with careful timing it is possible to avoid the referencing system with a second LaTeX run.

The example uses class book, where chaptermark, sectionmark and subsectionmark are redefined to include hyperlink with the current anchor @currentHref, which is defined quite right before either via refstepcounter or phantomsection for unnumbered section commands. Some patching is needed to insert partmark or to support starred section commands or commands. Also commands like tableofcontents, which uses @markboth, needs to be patched to get chaptermark.

The section titles in the example are taken from the start of the user manual of pgf to get a closer real document feeling.

documentclass{book}

usepackage[T1]{fontenc}
usepackage{lmodern}
usepackage{ragged2e}

usepackage{etoolbox}

usepackage{fancyhdr}
pagestyle{fancy}
fancyfoot{}
fancyhead{}
cfoot{thepage}
lhead{%
  RaggedRight
%  HeaderFont
  hypersetup{linkcolor=blue}%
  rightmark
}

newcommand*{HeaderFont}{%
  usefont{T1}{qhv}{c}{n}%
  small
}
makeatletter

DeclareRobustCommand*{BreadSep}{%
  ,textbf{guilsinglright}hspace{0pt},%
}
newcountbreadnav@level
breadnav@level=0 %

newcommand*{breadnav@starmark}[2]{%
  begingroup
    c@secnumdepth=-9 %
    #1{#2}%
  endgroup
}

patchcmd{@part}{markboth}{%
  partmark{#1}@gobbletwo
}{}{}
patchcmd{@spart}{normalfont}{%
  breadnav@starmarkpartmark{#1}%
  normalfont
}{}{}
newcommand*{partmark}[1]{%
  protected@xdefCurrentPart{%
    protecthyperlink{@currentHref}{%
      ifnumvalue{secnumdepth}>-2 %
        thepart@~%
      fi
      #1%
    }%
  }%
  markright{%
    CurrentPart
  }%
}
newcommand*{CurrentPart}{}

patchcmd{@schapterhead}{normalfont}{%
  breadnav@starmarkchaptermark{#1}%
  normalfont
}{}{}
patchcmd{tableofcontents}{@mkboth}{%
  breadnav@starmarkchaptermark{contentsname}%
  @gobbletwo
}
renewcommand*{chaptermark}[1]{%
  protected@xdefCurrentChapter{%
    protecthyperlink{@currentHref}{%
      ifnumvalue{secnumdepth}>-1 %
        if@mainmatter
          %@chapapp~
          thechapter.@~%
        fi
      fi
      #1%
    }%
  }%
  markright{%
    ifxCurrentPart@empty
    else
      CurrentPartBreadSep
    fi
    CurrentChapter  
  }%
}
newcommand*{CurrentChapter}{}

patchcmd{@startsection}{@ifstar}{%
  edefCurrentSectionType{#1}%
  @ifstar
}{%
  patchcmd{@ssect}{@tempskipa}{%
    expandafterbreadnav@starmark
    csnameCurrentSectionType markendcsname{#5}%
    @tempskipa
  }{}{}%
}{}
renewcommand*{sectionmark}[1]{%
  protected@xdefCurrentSection{%
    protecthyperlink{%
      @currentHref
    }{%
      ifnumvalue{secnumdepth}>0 %
        thesection.@~%
      fi
      #1%
    }%
  }%
  markright{%
    ifxCurrentPart@empty
    else
      CurrentPartBreadSep
    fi
    ifxCurrentChapter@empty
    else
      CurrentChapterBreadSep
    fi
    CurrentSection
  }%
}
newcommand*{CurrentSection}{}

renewcommand*{subsectionmark}[1]{%
  protected@xdefCurrentSubsection{%
    protecthyperlink{@currentHref}{%
      ifnumvalue{secnumdepth}>1 %
        thesubsection.@~%
      fi
      #1%
    }%
  }%
  markright{%
    ifxCurrentPart@empty
    else
      CurrentPartBreadSep
    fi
    ifxCurrentChapter@empty
    else
      CurrentChapterBreadSep
    fi
    ifxCurrentSection@empty
    else
      CurrentSectionBreadSep
    fi
    CurrentSubsection
  }%
}
newcommand*{CurrentSubsection}{}

letps@plainps@fancy
makeatother

usepackage[colorlinks]{hyperref}
usepackage{bookmark}
bookmarksetup{numbered,open}

usepackage{lipsum}

addtolength{textheight}{headheight}
setlength{headheight}{21pt}
addtolength{textheight}{-headheight}

begin{document}
title{Test document}
author{Me}
date{today}
maketitle
tableofcontents
chapter{Introduction}
lipsum
section{Structure of the System}
lipsum
section{Comparison with Other Graphics Packages}
lipsum
section{Utility Packages}
lipsum
section{How to Read This Manual}
lipsum
section{Authors and Acknowledgements}
lipsum
section{Getting Help}
lipsum
part{Tutorials and Guidelines}
chapter{Tutorial: A Picture for Karl's Students}
lipsum
section{Problem Statement}
lipsum
section{Setting up the Environment}
lipsum
subsection{Setting up the Environment in LaTeX}
lipsum
subsection{Setting up the Environment in Plain TeX}
lipsum
subsection{Setting up the Environment in ConTeX t}
lipsum
section{Straigt Path Construction}
lipsum
section{Curved Path Construction}
lipsum
section{Circle Path Construction}
lipsum
section{Rectangle Path Construction}
lipsum
end{document}

Result, page 8:

and page 25:

Discussion

IMHO the main problem is that breadcrumb headers take a lot of space as seen in the second shapshot, where the header already needs three lines.

The place can be reduced by:

• Using a shorter separation symbol, the example uses guilsinglright instead of the larger rightarrow.

• Smaller font sizes (small or footnotesize).

• Condensed font. Unfortunately these are not often available for the wanted font family.

The following snapshots show the result for the condensed font of Tex Gyre Hermes in size small if HeaderFont is enabled in lhead. This reduces the three lines to two of the second screen shot above:

Variant

Even more clearly arranged looks the navigation path if the levels are shown in separate lines with indentation. This can be achieved by the following definition of BreadSep (that does not support overlong titles that needs more than one line):

DeclareRobustCommand*{BreadSep}{%
  %
  advancebreadnav@level by 1 %
  hspace*{breadnav@leveldimexpr1emrelax}%
  textbf{guilsinglright},%
}

Screen shot with this definition and using small as HeaderFont:

However, this needs as much lines as supported section levels.

It would be nice if smaller headers could give the unneeded space back to the text body. But the page is build before the header and its free space is known. Remember the header size in a label raises the problem that the header can change if the page material is rearranged. Similar to package varioref this can cause documents that never stabilizes.