classification labels in headers and footers

Question

I'm trying to write Latex documents that will automatically satisfy government requirements for labeling certain classes of information:
- Each paragraph starts with a label indicating its importance.
- The header and footer of each page include a label indicating the most important paragraph on that page (even if it started on the previous page).

This is the closest I have come:

\documentclass[12pt]{report}
\usepackage{fancyhdr}
\usepackage{ifthen}
\usepackage{afterpage}
\usepackage{color}
\usepackage{lipsum}

\setlength\parskip{.6\baselineskip}
\setlength\parindent{0pt}
\setlength\headheight{15pt}
\setlength\textheight{21\baselineskip}
\newcommand\pageimport{TRIVIAL}
\newcommand\paraimport{TRIVIAL}

\pagestyle{fancy}
\lhead{}\chead{\leftmark}\rhead{}
\lfoot{}\cfoot{\leftmark}\rfoot{\thepage}

\newcommand{\IMP}[1]{\renewcommand\paraimport{IMPORTANT}
  \renewcommand\pageimport{IMPORTANT}
  \markboth{\pageimport}{\paraimport}
  \afterpage{\renewcommand\pageimport{\protect\paraimport}\markboth{\protect\paraimport}{}}
\textcolor{red}{(I)  #1}\renewcommand\paraimport{TRIVIAL}}

\newcommand{\TRI}[1]{\renewcommand\paraimport{TRIVIAL}
  \markboth{\pageimport}{\paraimport}
  \afterpage{\renewcommand\pageimport{\protect\paraimport}\markboth{\protect\paraimport}{}}
(U)  #1\renewcommand\paraimport{TRIVIAL}}

\begin{document}
\immediate\typeout{a. pageimport = \pageimport\space  paraimport = \paraimport}
\TRI{\lipsum[1]}
\TRI{\lipsum[2]}
\TRI{\lipsum[3]}
\immediate\typeout{b. pageimport = \pageimport\space  paraimport = \paraimport}
\IMP{\lipsum[4]}
\immediate\typeout{c. pageimport = \pageimport\space  paraimport = \paraimport}
\TRI{\lipsum[5]}
\TRI{\lipsum[6]}
\TRI{\lipsum[7]}
\TRI{\lipsum[8]}
\immediate\typeout{d. pageimport = \pageimport\space  paraimport = \paraimport}
\IMP{\lipsum[9]}
\immediate\typeout{e. pageimport = \pageimport\space  paraimport = \paraimport}
\TRI{\lipsum[10]}
\TRI{\lipsum[11]}
\TRI{\lipsum[12]}
\end{document}

(I've changed the labels here to avoid causing needless alarm. For convenience, I have also set the "important" text in red.) My idea is to keep the "importance" of each paragraph in \paraimport. That gets reset at the end of each paragraph. The header and footer get their labels from \pageimport, which records the highest importance on the current page. At the end of each page, \pageimport gets reset to the value of \paraimport.

This document has one "important" paragraph on page 2, and another that starts on page 4 and ends on page 5. All the paragraphs are correctly labeled. The first two pages have the right labels, but pages 3 and 6 should be marked "trivial". The tracing statements before and after each "important" paragraph show that \pageimport is not getting reset at the pagebreaks.

I suspect I'm moving something fragile, but rewriting the \afterpage commands as

\afterpage{\renewcommand\pageimport{\protect\paraimport}\markboth{\protect\paraimport}{}}

makes no difference.

I've seen secret.sty, but it's attacking a different problem. I have not been able to adapt it for page marking.

I'd appreciate any suggestions.

Answer 1

Here is a solution.

The key point is to reset left and right marks

\afterpage{%
\renewcommand\paraimport{TRIVIAL}%
\markboth{\paraimport}{\paraimport}

Note We need only one command \paraimport

Update the idea is to redefine \parimport and \markboth inside paragraphs i.e. just after (I).

Updated MWE

\documentclass[12pt]{report}
\usepackage{fancyhdr}
\usepackage{afterpage}
\usepackage{color}
\usepackage{lipsum}

\setlength\parskip{.6\baselineskip}
\setlength\parindent{0pt}
\setlength\headheight{15pt}
\setlength\textheight{21\baselineskip}


\pagestyle{fancy}
\lhead{}\chead{\leftmark}\rhead{}
\lfoot{}\cfoot{\leftmark}\rfoot{\thepage}

\newcommand\paraimport{TRIVIAL}
\markboth{\paraimport}{\paraimport}

\newcommand{\IMP}[1]{%
\textcolor{red}{(I)
\renewcommand\paraimport{IMPORTANT}%
\markboth{\paraimport}{\paraimport}%
 #1}%
\afterpage{%
\renewcommand\paraimport{TRIVIAL}%
\markboth{\paraimport}{\paraimport}}%
}

\newcommand{\TRI}[1]{(U)  #1}

\begin{document}
\TRI{\lipsum[1]}
\TRI{\lipsum[2]}
\TRI{\lipsum[3]}
\IMP{\lipsum[4]}
\TRI{\lipsum[5]}
\TRI{\lipsum[6]}
\TRI{\lipsum[7]}
\TRI{\lipsum[8]}
\IMP{\lipsum[9]}
\TRI{\lipsum[10]}
\TRI{\lipsum[11]}
\TRI{\lipsum[12]}
\end{document}

Answer 2

The question is a bit old, but it still comes up high on a web search. I was trying to adapt the solution for multiple importance levels and came across this answer to check if a paragraph spans a page break. My solution is to set a counter and increment the counter if a paragraph has a higher importance level than the current paragraph. If the last paragraph on the page spans the page break, I set the page level on the next page to the current level and repeat the process. What I came up with is

\documentclass{article}

\usepackage{afterpage}
\usepackage{lipsum}
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}

\newcounter{pagelevel}
\newcounter{currentlevel}

\usepackage{atbegshi}
\usepackage{zref-user}
\usepackage{zref-abspage}

\newcounter{clscnt}
\makeatletter
% When we ship out the page, check if the paragraph spans the break.
\AtBeginShipout{%
    \ifnum\zref@extract{markingenv-begin-\theclscnt}{abspage}
            =\zref@extract{markingenv-end-\theclscnt}{abspage}
        \setcounter{pagelevel}{0}%
    \else
        \setcounter{pagelevel}{\thecurrentlevel}%
    \fi
}
\makeatother

\newcommand{\marking}[2]{%
    \stepcounter{clscnt}%
    \zlabel{markingenv-begin-\theclscnt}%
    (#1 --- \thepagelevel)
    \ifnum #1 > \thepagelevel%
        \setcounter{pagelevel}{#1}%
        \chead{Level \thepagelevel}%
    \fi%
    \setcounter{currentlevel}{#1}
    #2
    \zlabel{markingenv-end-\theclscnt}%
}

\newcommand{\VI}[1]{\marking{3}{(V) #1}}
\newcommand{\IMP}[1]{\marking{2}{(I) #1}}
\newcommand{\TRI}[1]{\marking{1}{(U) #1}}

\begin{document}
\TRI{\lipsum[1]\par}
\TRI{\lipsum[2]\par}
\TRI{\lipsum[3]\par}
\IMP{\lipsum[4]\par}
\TRI{\lipsum[5]\par}
\TRI{\lipsum[6]\par}
\TRI{\lipsum[7]\par}
\TRI{\lipsum[8]\par}
\IMP{\lipsum[9]\par}
\TRI{\lipsum[10]\par}
\TRI{\lipsum[11]\par}
\TRI{\lipsum[12]\par}
\TRI{\lipsum[13]\par}
\TRI{\lipsum[14]\par}
\TRI{\lipsum[15]\par}
\VI{\lipsum[16]\par}
\IMP{\lipsum[17]\par}
\TRI{\lipsum[18]\par}
\TRI{\lipsum[19]\par}
\TRI{\lipsum[20]\par}
\TRI{\lipsum[21]\par}
\TRI{\lipsum[22]\par}
\TRI{\lipsum[23]\par}
\TRI{\lipsum[24]\par}
\TRI{\lipsum[25]\par}
\TRI{\lipsum[26]\par}
\TRI{\lipsum[27]\par}
\TRI{\lipsum[28]\par}
\TRI{\lipsum[29]\par}
\end{document}

I modified the example to explicitly show the page level and paragraph level. Note that pages 3 and 4 correctly have the heading set to level 3 and the heading is reset to 1 on pages 5 and 6.

---

Edit: I've been tinkering with and extending this solution to make it into a package.

Answer 3

It seems as though the most complicated part of this problem is the case when a paragraph continues through a page break. Perhaps the easiest thing to do is to prevent paragraphs from doing so:

\widowpenalties 1 10000
\raggedbottom