Displaying tooltips on tablet readers, specifically iPad

Question

I am trying to generate tooltips in a PDF that will be accessible somehow on a tablet PDF reader, specifically on any iPad reader. So far, I have tried the packages pdfcomment, cooltooltips, and fancytooltips, but none of these were accessible on the iPad with Adobe Reader as a reference.

I am aware that tooltips on a tablet don't make much sense since there is no such thing as a mouse over, but maybe there is something similar that works with a box that opens and closes on click or something. For example, I found something similar for the Safari browser which uses JavaScript's jQuery:

http://code.drewwilson.com/entry/tiptip-jquery-plugin

Is there any way I could get something like that working or can you think of a reasonable work-around? Or does that actually work already and am I just using the wrong PDF viewer/settings/anything? My current solution would be to use notes at the end of the PDF and hyperref to jump between pages, but I'd like to have something more elegant.

Thank you for any hints or comments.

Answer 1

The minimal tooltip macro definition below uses mouse-down and up events in addition to roll-over and out for showing/hiding the tooltip. This works in Adobe Reader on my PC. Take it as a proof of concept if it works on a tablet or phone too. In case of multiline tooltips, the tip text should be put into a \parbox[b]{}{}.

\documentclass{article}
\usepackage{color}
\usepackage{calc}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% usage: \tooltip{<link text>}{<tip text>}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\newcommand\tooltip[2]{%
  \leavevmode%
  \immediate\pdfobj{<</S/Hide/T (tip\thetcnt)/H false>>}%
  \edef\showaction{\the\pdflastobj\space 0 R}%
  \immediate\pdfobj{<</S/Hide/T (tip\thetcnt)/H true>>}%
  \edef\hideaction{\the\pdflastobj\space 0 R}%
  \pdfstartlink
    user{
      /FT/Btn/Ff 65536/T(lnk\thetcnt)/H/N
      /Subtype/Widget/AA <<
        /D \showaction /U \hideaction
        /E \showaction /X \hideaction
        /PO \hideaction
      >>
    }{\color{red}#1}%
  \pdfendlink%
  \sbox\tiptext{\colorbox[gray]{0.8}{#2}}%
  \edef\twd{\the\wd\tiptext}%
  \edef\tht{\the\ht\tiptext}%
  \edef\tdp{\the\dp\tiptext}%
  \immediate\pdfxform\tiptext%
  \raisebox{\heightof{#1}}{%
    \pdfannot width \twd height \tht depth \tdp {
      /Subtype/Widget/FT/Btn/Ff 65537/T (tip\thetcnt)
      /AP <</N \the\pdflastxform\space 0 R>>
    }%
  }%    
  \stepcounter{tcnt}%
}
\newsavebox\tiptext\newcounter{tcnt}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}\Huge
  Einstein's \tooltip{formula}{$E=m c^2$} is well known.
  Another famous formula is due to \tooltip{Pythagoras}{$a^2+b^2=c^2$}.
\end{document}