How to use \pageref{foo} as a number?

Question

What I want to do is to show a "progress bar" in the header to show how far you are in the document, by making a rule with width pagenumber divided by total pages times the paper width.

This is what I have:

\usepackage{fancyhdr,lastpage}
\pagestyle{fancy}
\lhead{\rule{\value{page}/\value{\pageref{LastPage}}*120mm}{2mm}}

but obviously it doesn't work.

Answer 1

Solving this kind of problem is the raison d'être of the refcount package. Here's one way to use it:

\documentclass[oneside]{book}
\usepackage{lipsum,fancyhdr,lastpage,refcount}
\pagestyle{fancy}
\setrefcountdefault{-1}
\lhead{\rule{\dimexpr \textwidth * \thepage/\getpagerefnumber{LastPage}}{2mm}}
\begin{document}
\lipsum[1-60] %Insert dummy text for demonstration
\end{document}

Answer 2

The code of Lev will break if the page number is not a number, e.g. with \pagenumbering{Roman}. I would use the zref package:

\documentclass[oneside]{book}
\usepackage{lipsum,fancyhdr}
\pagestyle{fancy}
\usepackage[lastpage]{zref}
\pagenumbering{Roman}
\makeatletter
\zref@newprop*{numpage}{\the\value{page}}
\zref@addprop{main}{numpage}
\lhead{\rule{\dimexpr \textwidth * \the\value{page}/\zref@extractdefault{LastPage}{numpage}{1}}{2mm}}
\makeatother
\begin{document}
\lipsum[1-60] %Insert dummy text for demonstration
\end{document}

(Instead of the new property "numpage" one could also use "abspage" if the absolute page number is wanted.)

Answer 3

It's slightly tricky to do this since you need to unroll what \pageref does, but what you need to do basically boils down to this.

\newcount\lastpagecount
\makeatletter
\AtBeginDocument{%
        \expandafter\ifx\csname r@LastPage\endcsname\relax
                \lastpagecount\m@ne
        \else
                \lastpagecount\expandafter\@secondoftwo\r@LastPage\relax
        \fi
}
\lhead{%
        \begingroup
                \ifnum\c@page>\lastpagecount
                        \count@\c@page
                \else
                        \count@\lastpagecount
                \fi
                \dimen@\dimexpr 120mm * \c@page/\count@\relax
                \rule{\dimen@}{2mm}%
        \endgroup
}
\makeatother

The code being passed to \AtBeginDocument checks to see if the LastPage reference has been set. If it hasn't, it sets the \lastpagecount to -1. If it has, then it sets \lastpagecount to be the value of the last page.

Then, in \lhead, \count@ is set to the maximum of the current page and the last page. Note that it's possible for the current page to be greater than the last page because you need to compile at least twice to find the real last page number. Then it uses \dimexpr ... \relax to compute the length of the rule.

This didn't get extensive testing, but it seems to work.

Answer 4

This one is tricky, unfortunately catching me and I'm guessing a few others out by the way it was originally framed. Edootjuh's problem has nothing to do with whether calc (or in fact whether \dimexpr) can execute a divide. It (they) can. Rather, it has to do with whether \pageref{LastPage} (or as far as I can work out, any expression based on \pageref{LastPage}) can stand as an operand in the divide.

The problem is trivially solved if (as in Aditya's contribution) the last page number is hard-coded as a literal. It is much less easily solved if this value is pulled in via a \pageref to a label. Ultimately, the problem that needs to be solved is this:

\documentclass{article}
\usepackage{fancyhdr}
\usepackage{calc}
\usepackage{lipsum}

\pagestyle{fancy}
\lhead{\rule{\textwidth * \thepage / 6}{2mm}}                     % <-- works fine, trivial solution
%\lhead{\rule{\textwidth * \thepage / \pageref{LastPage}}{2mm}}   % <-- any form of reference to a label fails

\begin{document}
\pageref{LastPage}

\rule{\dimexpr 120mm*1/6 \relax}{2mm}   % solution requires reference to LastPage label rather than a hard-coded literal here 

\lipsum[1-30]
\label{LastPage}
\end{document}

Answer 5

OK, you got already 4 answers, but to give still more options to other people looking up the question:

As you already are useing the lastpage package, you can also use \lastpage@lastpage (at least with the recent version 1.2k):

\documentclass[oneside]{book}
\usepackage{fancyhdr,lastpage}
\pagestyle{fancy}
\makeatletter
\def\lastpage@lastpage{1000}% because \lastpage@lastpage is undefined before
% the .aux file has been loaded at the begin of the document
% (and during the first compilation run).
\lhead{\rule{\dimexpr \textwidth*\thepage/\lastpage@lastpage \relax}{2mm}}%
\makeatother
\usepackage{lipsum}
\begin{document}
\lipsum[1-60] % inserts dummy text for demonstration.
\end{document}

BUT when another pagenumbering scheme (e.g. Roman) is used, or the pagenumbers are reset, this will not work, e.g. \lastpage@lastpage could be X (Roman for 10), and pages put out with \AtEndDocument might not be counted (depending on loading order of the packages). In those cases the pageslts package (v1.2a) could be used:

\documentclass[oneside]{book}
\usepackage{fancyhdr,pageslts}
\setcounter{pagesLTS.pagenr}{1000}
% because pagesLTS.pagenr is zero before
% the .aux file has been loaded at the begin of the document
% (and during the first compilation run).
\pagestyle{fancy}
\lhead{\rule{\dimexpr \textwidth*\theCurrentPage/\the\value{pagesLTS.pagenr}\relax}{2mm}}%
\usepackage{lipsum}
\begin{document}
\pagenumbering{arabic}
\lipsum[1-30] % inserts dummy text for demonstration.
\clearpage
\pagenumbering{Roman}
\lipsum[31-60] % inserts dummy text for demonstration.
\end{document}

(I also replace the fixed 120mm by \textwidth.)