Copyable math formulas

Question

I'm curious whether there is a package that allows to copy math formulas correctly.

For example, this one should highlight like so

but, not like so

And if I copy one, I should get:

∫₃⁵ (x/(1-x²)) dx

If there is no such a package, I'm looking for an any manual way of doing this.

For example, I can make a phantom text to make the selection highlight correct. But I don't know how to get custom text by copying.

Answer 1

I managed to do that! Thanks for this answer.

\documentclass{article}
\usepackage{fontspec}
\usepackage{accsupp}

\usepackage{tikz}
\usepackage{stringenc}
\usepackage{pdfescape}
\usetikzlibrary{calc}
\makeatletter
\newcommand{\BeginAccSuppUnicode}[1]{%
    \EdefSanitize\asu@str{#1}%
    \edef\asu@str{%
        \expandafter\expandafter\expandafter\asu@ToSpaceOther
        \expandafter\asu@str\space\@nil
    }%
    \expandafter\let\expandafter\asu@str\expandafter\@empty
    \expandafter\asu@ToHexUC\asu@str\relax
    \EdefUnescapeHex{\asu@str}{\asu@str}%
    \StringEncodingConvert{\asu@str}{\asu@str}{utf32be}{utf16be}%
    \EdefEscapeHex{\asu@str}{\asu@str}%
    \BeginAccSupp{%
        unicode,%
        method=hex,%
        ActualText=\asu@str
    }%
}
\begingroup
\lccode`\9=`\ %
\lowercase{\endgroup
    \def\asu@SpaceOther{9}%
}
\def\asu@ToSpaceOther#1 #2\@nil{%
    #1%
    \ifx\\#2\\%
    \expandafter\@gobble
    \else
    \asu@SpaceOther
    \expandafter\@firstofone
    \fi
    {\asu@ToSpaceOther#2\@nil}%
}
\def\asu@ToHexUC#1{%
    \ifx#1\relax
    \else
    \pgfmathHex{\the\numexpr`#1+"10000000\relax}%
    \edef\asu@str{%
        \asu@str
        0\expandafter\@gobble\pgfmathresult
    }%
    \expandafter\asu@ToHexUC
    \fi
}
\makeatother

\begin{document}

\begin{tikzpicture}[remember picture,overlay]
\node[text opacity=0]at ($(current page.north west)+(70.5ex,-37ex)$){
\BeginAccSuppUnicode{∫₃⁵ (x/(1-x²)) d}  
    \scalebox{14}[7.2]{x\rule{1pt}{0pt}}
\EndAccSupp{}
\hspace{-23pt}\scalebox{0.1}[7.2]{x}
};
\end{tikzpicture}

\[ \int_3^5\frac{x}{1-x^2}\,dx \]

\end{document}

---

Edit

Found another solution that works the same. Although it requires you to manualy convert all symbols to unicode, it is way more compact.

\documentclass{article}
\usepackage{accsupp}

\usepackage{tikz}
\usetikzlibrary{calc}

\begin{document}

\begin{tikzpicture}[remember picture,overlay]
\node[text opacity=0]at ($(current page.north west)+(70.5ex,-37ex)$){
\BeginAccSupp{method=hex,unicode,ActualText=222b20832075 00280078002f00280031002d007800b200290029 0064}
    \scalebox{14}[7.2]{x\rule{1pt}{0pt}}
\EndAccSupp{}
\hspace{-23pt}\scalebox{0.1}[7.2]{x}
};
\end{tikzpicture}