namestack.tex

%% \namestack for making overlay/superposed stacks of names/text

\usepackage[final]{pdfcomment} % for tooltips
\usepackage{accsupp}           % for accessibility
\usepackage{pgf}               % for transparency

% Usage: \textopacity{opacity}{text}
% transparency.sty doesn't blend well in Acrobat, so we use PGF;
% see https://tex.stackexchange.com/a/681324/245104
\newcommand\textopacity[2]{%
  \begin{pgfpicture}%
    \pgfsetfillopacity{#1}%
    \pgfpathmoveto{\pgfpointorigin}%
    \pgftext[base]{#2}%
  \end{pgfpicture}%
}

% Usage: \textstack{opacity}{item1; item2; ...}
% Or: \textstack[sep]{opacity}{item1 sep item2 sep ...}
% Expands to \vbox{\hbox{item1}\vskip-\baselineskip\hbox{item2}...},
% plus a PDF tooltip, copy/paste override, and specified opacity.
% Loop iteration based on https://tex.stackexchange.com/a/159177/245104
\makeatletter
\newlength\textstack@height
\newcommand\textstack[3][;]{%
  % Append separator (#1) and \@eol to end of input:
  \def\textstack@append##1{\expandafter\textstack@step##1#1\@eol}%
  % Split into first component (##1) up to separator (#1), and rest (##2):
  \def\textstack@step##1#1##2\@eol{%
    % Build \hbox for this component (##1) with specified opacity (#2),
    % while saving height in \textstack@height
    \setbox1=\hbox{\textopacity{#2}{\ignorespaces ##1\unskip}}%
    \setlength\textstack@height{\ht1}%
    \box1%
    \ifx\@eol##2\@eol\else
      % More steps: unwind vertical space and continue
      \nointerlineskip
      \vskip-\textstack@height
      \textstack@step##2\@eol
    \fi}%
  % Tooltip with full author list (#3)
  \pdftooltip{%
    % Override copy/paste text with full author list (#3)
    \BeginAccSupp{method=pdfstringdef,unicode,ActualText={#3}}%
      % Wrap stack in \vbox
      \vbox{\textstack@append{#3}}%
    \EndAccSupp{}%
  }{#3}%
}
\makeatother

% Usage: \namestack{name1; name2; ...}
% Or: \namestack[opacity]{name1; name2; ...}
% Like \textstack but with optional opacity defaulting to 2/3
\newcommand\namestack[2][0.666]{\textstack{#1}{#2}}