Okay jumping on the old horse! ;-)
Meanwhile Acrobat Reader X offers some simple possibilities for PDF annotations. If you want to do more you can use the pdfcomment package, e.g. for your examples:
\documentclass[a4paper]{article}
\usepackage[latin1]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage[rgb]{xcolor}
\usepackage[author={Max Schlepzig}]{pdfcomment}
\begin{document}
Here we\pdfcomment[color=red,icon=Insert]{insert: miss} a word!
You can do much more \pdfmarkupcomment[markup=Squiggly,color=green]{with pdfcomment}{move to the front}.
This is a \pdfmarkupcomment[markup=StrikeOut,color=red]{stupid}{replace stupid with funny} game!
\pdfmarkupcomment[markup=Highlight,color=yellow]{Of course, you can highlight complete sentences.}{Highlight}
This is very\pdfcomment[icon=Note,color=blue]{insert graphic!} interesting!
\end{document}
This would require hacking the fancytooltips package.
Since fancytooltips depends on packages which are not in TeXLive, I tried something on my own.
The tool-tip command defined below supports all common output drivers (LaTeX workflows):
latex->dvips->ps2pdf (dvips must not be called with option -Ppdf!)latex->dvipdfmxxelatex, lualatex, pdflatex
The command
\tooltip[<link text colour>]{<link text>}[<tip box colour>]{<tip text>}
creates a tooltip that can be dragged around.
The colour arguments are optional and default to blue and yellow!20. Predefined colour names and colour expressions according to the colour-model of the xcolor package can be used. Ifhyperref is loaded, its colour setting for internal links (option linkcolor) is used as <link text colour>.
<link text> is breakable across line endings, except for the latex->dvips->ps2pdf workflow.
Multi-line <tip text> should be put into a \parbox or minipage.
\documentclass[a6paper,12pt]{scrbook}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% tooltips with LaTeX v. 2017/11/28
%
% \tooltip[*[*[*[*]]]][<link colour>]{<link text>}[<tip box colour>]{<tip text>}
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% \tooltip --> draggable tip, visible on mouse-over, hidden on mouse-out
%
% \tooltip* --> draggable tip, toggle visiblity on mouse-over
%
% \tooltip** --> NON-draggable tip, visible on mouse-over, hidden on mouse-out
%
% \tooltip*** --> NON-draggable tip, toggle visiblity on mouse-over
%
% \tooltip**** --> NON-draggable tip, toggle visiblity on mouse-click (Evince!)
%
% Default link colour can be set with
%
% \usepackage[linkcolor=<colour>]{hyperref}
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage{pdfbase}[2017/03/16]
\usepackage{xparse,ocgbase}
\usepackage{xcolor,calc}
\usepackage{tikzpagenodes}
\usetikzlibrary{calc}
\ExplSyntaxOn
\let\tpPdfLink\pbs_pdflink:nn
\let\tpPdfAnnot\pbs_pdfannot:nnnn\let\tpPdfLastAnn\pbs_pdflastann:
\let\tpAppendToFields\pbs_appendtofields:n
\def\tpPdfXform{\pbs_pdfxform:nnnnn{1}{1}{}{}}
\let\tpPdfLastXform\pbs_pdflastxform:
\ExplSyntaxOff
\makeatletter
\NewDocumentCommand{\tooltip}{%
ssssO{\ifdefined\@linkcolor\@linkcolor\else blue\fi}mO{yellow!20}m%
}{{%
\leavevmode%
\IfBooleanT{#2}{%
%for variants with two and more stars, put tip box on a PDF Layer (OCG)
\ocgbase@new@ocg{tipOCG.\thetcnt}{%
/Print<</PrintState/OFF>>/Export<</ExportState/OFF>>%
}{false}%
\xdef\tpTipOcg{\ocgbase@last@ocg}%
%prevent simultaneous visibility of multiple non-draggable tooltips
\ocgbase@add@ocg@to@radiobtn@grp{tool@tips}{\ocgbase@last@ocg}%
}%
\tpPdfLink{%
\IfBooleanTF{#4}{%
/Subtype/Link/Border[0 0 0]/A <</S/SetOCGState/State [/Toggle \tpTipOcg]>>
}{%
/Subtype/Screen%
/AA<<%
\IfBooleanTF{#3}{%
/E<</S/SetOCGState/State [/Toggle \tpTipOcg]>>%
}{%
\IfBooleanTF{#2}{%
/E<</S/SetOCGState/State [/ON \tpTipOcg]>>%
/X<</S/SetOCGState/State [/OFF \tpTipOcg]>>%
}{
\IfBooleanTF{#1}{%
/E<</S/JavaScript/JS(%
var fd=this.getField('tip.\thetcnt');%
if(typeof(click\thetcnt)=='undefined'){%
var click\thetcnt=false;%
var fdor\thetcnt=fd.rect;var dragging\thetcnt=false;%
}%
if(fd.display==display.hidden){%
fd.delay=true;fd.display=display.visible;fd.delay=false;%
}else{%
if(!click\thetcnt&&!dragging\thetcnt){fd.display=display.hidden;}%
if(!dragging\thetcnt){click\thetcnt=false;}%
}%
this.dirty=false;%
)>>%
}{%
/E<</S/JavaScript/JS(%
var fd=this.getField('tip.\thetcnt');%
if(typeof(click\thetcnt)=='undefined'){%
var click\thetcnt=false;%
var fdor\thetcnt=fd.rect;var dragging\thetcnt=false;%
}%
if(fd.display==display.hidden){%
fd.delay=true;fd.display=display.visible;fd.delay=false;%
}%
this.dirty=false;%
)>>%
/X<</S/JavaScript/JS(%
if(!click\thetcnt&&!dragging\thetcnt){fd.display=display.hidden;}%
if(!dragging\thetcnt){click\thetcnt=false;}%
this.dirty=false;%
)>>%
}%
/U<</S/JavaScript/JS(click\thetcnt=true;this.dirty=false;)>>%
/PC<</S/JavaScript/JS (%
var fd=this.getField('tip.\thetcnt');%
try{fd.rect=fdor\thetcnt;}catch(e){}%
fd.display=display.hidden;this.dirty=false;%
)>>%
/PO<</S/JavaScript/JS(this.dirty=false;)>>%
}%
}%
>>%
}%
}{{\color{#5}#6}}%
\sbox\tiptext{%
\IfBooleanT{#2}{%
\ocgbase@oc@bdc{\tpTipOcg}\ocgbase@open@stack@push{\tpTipOcg}}%
\fcolorbox{black}{#7}{#8}%
\IfBooleanT{#2}{\ocgbase@oc@emc\ocgbase@open@stack@pop\tpNull}%
}%
\edef\twd{\the\wd\tiptext}%
\edef\tht{\the\ht\tiptext}%
\edef\tdp{\the\dp\tiptext}%
\measureremainder{\whatsleft}\tipshift=0pt%
\ifdim\whatsleft<\twd\setlength\tipshift{\whatsleft-\twd}\fi%
\IfBooleanF{#2}{\tpPdfXform{\tiptext}}%
\raisebox{\heightof{#6}+\tdp}[0pt][0pt]{\makebox[0pt][l]{\hspace{\tipshift}%
\IfBooleanTF{#2}{\usebox{\tiptext}}{%
\tpPdfAnnot{\twd}{\tht}{\tdp}{%
/Subtype/Widget/FT/Btn/T (tip.\thetcnt)%
/AP<</N \tpPdfLastXform>>%
/MK<</TP 1/I \tpPdfLastXform/IF<</S/A/FB true/A [0.0 0.0]>>>>%
/Ff 65536/F 3%
/AA <<%
/U <<%
/S/JavaScript/JS(%
var fd=event.target;%
var mX=this.mouseX;var mY=this.mouseY;%
var drag=function(){%
var nX=this.mouseX;var nY=this.mouseY;%
var dX=nX-mX;var dY=nY-mY;%
var fdr=fd.rect;%
fdr[0]+=dX;fdr[1]+=dY;fdr[2]+=dX;fdr[3]+=dY;%
fd.rect=fdr;mX=nX;mY=nY;%
};%
if(!dragging\thetcnt){%
dragging\thetcnt=true;Int=app.setInterval("drag()",1);%
}%
else{app.clearInterval(Int);dragging\thetcnt=false;}%
this.dirty=false;%
)%
>>%
>>%
}%
\tpAppendToFields{\tpPdfLastAnn}%
}%
}}%
\stepcounter{tcnt}%
}}
\makeatother
\newsavebox\tiptext\newcounter{tcnt}
\newlength{\whatsleft}\newlength{\tipshift}
\newcommand{\measureremainder}[1]{%
\begin{tikzpicture}[overlay,remember picture]
\path let \p0 = (0,0), \p1 = (current page.east) in
[/utils/exec={\pgfmathsetlength#1{\x1-\x0}\global#1=#1}];
\end{tikzpicture}%
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\parindent=0pt
\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}
How it works:
Two PDF-Annotations (mouse-sensitive regions) are created: (1) A link around the blue link text, which is breakable across line endings. (2) An interactive (/Ff 65536) button (/FT/Btn) widget (/Subtype/Widget) for the tip text.
Visibility of the tip box is controlled via a JavaScript action that is bound to the mouse-enter event of the link. In order to show/hide the tip it is sufficient to repeatedly hover the mouse pointer over the link text.
The tip text may not be directly embedded into the page content; it couldn't be moved around otherwise. Rather, it is typeset into a box (\sbox) and subsequently distilled into a so-called Form-XObject, which is a self-contained PDF entity with graphical and/or textual content. This Form-XObject is bound to the button widget appearance via the /MK entry.
The dragging is implemented as a JavaScript action, which is triggered by the mouse-up event of the tip-text button. The mouse movement is tracked by the function drag() which is repeatedly executed using a JavaScript timer (app.setInterval). The deltas of the mouse position thus determined are continuously added to the coordinates (rect property) of the JavaScript Field object that represents the tip-text button.
Best Answer
I think what you want does not exist. Apart from the commands provided by packages like fancytooltips or cooltooltips (and the PDF specials they employ), there is no way of putting tooltips into PDFs. What you are observing in evince is not a different kind of tooltip, but just a built-in reaction to the presence of a hyperlink in the document. (Yes, it's in xpdf too, but keep in mind that the poppler libraries that evince and okular run on are derived from xpdf.) What's being "read" from the PDF is just the hyperlink. And it's not true that you'll see the same behavior in all "sane" PDF viewers: hyperlinks that produce tooltips like these in evince do not do so for Ghostview (gv), or MuPDF, or Zathura (which I consider to be reasonable PDF viewers).