[pdftex] Hover effects in pdftex.

[Heiko Oberdiek]

On Fri, Nov 04, 2005 at 09:34:38PM +0000, Tigran Aivazian wrote:

> On Tue, 1 Nov 2005, John R. Culleton wrote:
> >Once again I am late to the party. Is it the same mechanism as
> >pdfannot? Can you suggest a document or example to read?

Try this (tested with AR7/Linux and AR5/Linux):

\documentclass[10pt,a5paper,twoside]{book}

\usepackage[bookmarks=false]{hyperref}
% only used for \pdfstringdef 

\makeatletter
\newcounter{tooltip at counter}   
\setcounter{tooltip at counter}{0}

\newcommand{\annotate}[2]{%
  \stepcounter{tooltip at counter}%
  \pdfstringdef\tooltip at pdfstring{#2}%
  % For each annotation the /T field must be different.
  % This is not supported by \pdfstartlink, if the link
  % is broken across lines.
  \mbox{%
    \pdfstartlink user{%
      /Subtype/Widget%
      /T(tooltip\number\value{tooltip at counter})% unique name
      /FT/Btn%
      /TU(\tooltip at pdfstring)% tooltip text
    }% 
    #1%
    \pdfendlink
  }%
}
\makeatother

\begin{document} 
\pagestyle{empty}

\annotate{Hellog}{English greeting.} 
\annotate{world}{Whole planet Earth.}
\annotate{and}{English conjunction.}
\annotate{the}{English definite article.}
\annotate{rest}{The rest, you know.}
\annotate{of}{Short English word.}
\annotate{the}{English definite article.}
\annotate{Universe!}{A differentiable manifold.}

% ...
\end{document}

> You can gather bits of knowledge from movie15.sty and some other bits of 
> knowledge from attachfile.sty. You can also try the enclosed example I 
> wrote when I was experimenting with this feature. This example is not 
> complete, i.e. I wasn't able to get the appearances working correctly and 
> so an icon is displayed if you click on the active area.
> 
> Also, it is very unstable, i.e. you have to position the mouse very 
> carefully to get it right.

The /Text annotation doesn't use the rectangle, it puts a
sticky note at the upper left corner, more or less visible.
The size of the rectangle is invariant regarding the current
zoom level.

> Ok, I know that my sample is far from perfect, but since it is the only 
> thing that exists (to my knowledge) that even attempts to do this --- it 
> is a good place to start. And don't forget to email me the working version 
> when you have fixed it :)

Some hints:

> \immediate\pdfxform attr {
> 	/Subtype /Form
> } \appbox

pdfTeX already adds this, thus this "attr{...}" part can be dropped.

> \newcommand{\annotate}[2]{%
> #1%

You can have line/page breaks, strechable/shrinkable glue inside #1.

> \settowidth{\wordwidth}{\mbox{#1}}%
> \settoheight{\wordheight}{\mbox{#1}}%
> \settodepth{\worddepth}{\mbox{#1}}%

The \setto... macros already put the argument in a box, thus
the additional \mbox level is not necessary.

>   {
>     /Subtype /Text
>     /T (word: #1)
>     /Contents (Explanation: #2)
>     /AP << /N \theappobj\space 0 R >>
>   }%
> }

You can get smaller PDF file sizes if the unnecessary spaces
are removed, eg. before "/", "<", "(", "[" or after ")", "]" and ">".

Yours sincerely
  Heiko <oberdiek at uni-freiburg.de>
--