Using \hyperlink to link text to page with an implicit page anchor not known in advance

Question

hyperref provides the command \hyperlink, with syntax:

\hyperlink{name}{text}

where name is the name of a hypertext object, and text is used as the link to jump to the defined mark. Page anchors, e.g., page.12, can also be used as hypertext objects. For example,

Click \hyperlink{page.23}{here} to jump to page 23.

This was proposed by Martin Scharrer as a solution to this problem.

I would like to link a string of text to a page (by page number) using \hyperlink, but being able to refer to an implicit page anchor page.<number> whose ''number'' is not known in advance. That is, use a value of the counter page, which is only set later in the document, in the argument of \hyperlink.

Here's a hypothetical solution:

\documentclass{article}

\usepackage[pageanchor]{hyperref} % option is the default anyway

%% Martin Scharrer's patch for hyperref
%% available at https://tex.stackexchange.com/a/19416/9237
\makeatletter
\let\orig@Hy@EveryPageAnchor\Hy@EveryPageAnchor
\def\Hy@EveryPageAnchor{%
    \begingroup
    \hypersetup{pdfview=Fit}%
    \orig@Hy@EveryPageAnchor
    \endgroup
}
\makeatother 

\def\getpageref{???}   % \getpageref extracts the numeric value of \pageref{key}
                       % for use in the first argument of \hyperlink

\begin{document}

See
\hyperlink{page.\getpageref{lkd}}{this page}
for further clarification.

\newpage

This is the linked page.\label{lkd}

\end{document}

I know how to achieve a similar solution by simply using \label and then \pageref (or \autopageref), but I am interested in making use of a hyperref patch proposed here by Martin to make all page anchors be displayed in full page mode. (This patch only seems to work with \hyperlink.)

Answer 1

You can label the page you want to link to using the normal \label command, and extract its page number with \getpagerefnumber from the refcount package to use it in the \hyperlink (the "normal" LaTeX macro \pageref doesn't work here, as it is not expandable).

A small example:

\documentclass{article}

\usepackage{refcount}
\usepackage[pageanchor]{hyperref}

%% Martin's patch for hyperref
\makeatletter
\let\orig@Hy@EveryPageAnchor\Hy@EveryPageAnchor
\def\Hy@EveryPageAnchor{%
    \begingroup
    \hypersetup{pdfview=Fit}%
    \orig@Hy@EveryPageAnchor
    \endgroup
}
\makeatother 

\begin{document}

See
\hyperlink{page.\getpagerefnumber{mypage}}{this page}
for further clarification.
\clearpage

\dots
\clearpage

This is the linked page.\label{mypage}

\end{document}

Answer 2

I tried last night some things, but got only errors, as I played with \pageref*. But diabonas’ answer gave me the decisive hint. So here’s my solution without \hyperlink. It uses the alternative definition \hyperref{URL}{category}{label}{text} instead with category = “page”. It’s especially useful for external resources (PDF in external URL needs of course page anchors, and it works, as far as I know, only with the browser plugin version of Adobe Reader). In my MWE the URL is set to ./\jobname.pdf, what will be converted into the local PDF file. It works exactly as wanted by the OP.

\documentclass{article}
\usepackage[latin,english]{babel} % needed for "blindtext",
                                  % "english" is the active language
\usepackage{blindtext,lipsum,kantlipsum} % just for the examples

\usepackage{refcount}% from "oberdiek" bundle

\usepackage[%
  colorlinks=true,%
  linkcolor=green,%
%  filecolor=cyan,% it's the default
]{hyperref}

%%% Patch from Martin Scharrer
%%% cf. https://tex.stackexchange.com/a/19416/9237
\makeatletter
\let\orig@Hy@EveryPageAnchor\Hy@EveryPageAnchor
\def\Hy@EveryPageAnchor{%
    \begingroup
    \hypersetup{pdfview=Fit}%
    \orig@Hy@EveryPageAnchor
    \endgroup
}
\makeatother

%%% \mypageref{<label>}{some linked text}
\newcommand{\mypageref}[2]{\hyperref{./\jobname.pdf}{page}{\getpagerefnumber{#1}}{#2}}

\begin{document}

\section{Package \texttt{blindtext}}

\subsection{English blindtext}\label{btext-en}
See also package \hyperref[klipsum]{\ttfamily kantlipsum} on
\mypageref{klipsum}{next page}.

\medskip

\blindtext[1]

\subsection{Latin blindtext}\label{btext-la}
Compare package \hyperref[lipsum]{\ttfamily lipsum} on
\mypageref{lipsum}{page \pageref*{lipsum}}.

\medskip

\begin{otherlanguage}{latin}
\blindtext[1]
\end{otherlanguage}

\newpage

\section{Package \texttt{kantlipsum}}\label{klipsum}
See also package \hyperref[btext-en]{\texttt{blindtext} with English text} on
\mypageref{btext-en}{previous page}.

\medskip

\kant[1]

\section{Package \texttt{lipsum}}\label{lipsum}
Compare package \hyperref[btext-la]{\texttt{blindtext} with pseudo-Latin text} on
\mypageref{btext-la}{page \pageref*{btext-la}}.

\medskip

\begin{otherlanguage}{latin}
\lipsum[1]
\end{otherlanguage}

\end{document}

_{MWE happily stolen from myself: Representing hyperlinks differently in a single pdf file.}