使用 vwcol 添加脚注

Question

这种情况有两个问题。第一个问题是将vwcol内容设置为\parbox，它不显示脚注。请参阅为什么 \parbox 会丢失脚注？进行更多讨论，并通过重新定义找到解决方案\@footnotetext。

第二个问题是，vwcol在循环中多次处理相同的输入，以计算正确的列分布。每次处理输入时，脚注计数器都会增加。文档中实际使用了最后一次运行，显示的脚注计数器跳过了前几次运行的值。

为了解决这个问题，您可以在第一次运行时只处理脚注（以在页面底部显示正确的数字并防止多次添加相同的脚注）。但是，现在段落中不显示数字，因为这是上次运行的结果。因此，您可以使用仅打印数字\footnotemark，并在每次运行之前将此数字重置为初始值。

实现上述目标的一个相对简单的方法是定义一个新的脚注命令，供在vwcol环境中使用（\footnotevwc在下面的 MWE 中）。对其余代码的必要修改很小（总共 8 行代码），但由于vwcol使用了包\NewEnvironment中的代码environ，因此不幸的是代码无法轻松修补。相反，在下面的代码中使用了环境的完整重新定义，从源代码复制而来。另一个问题vwcol中的脚注代码是另外 20 行。\parbox

完整 MWE：

\documentclass{article}
\usepackage[totalheight=8cm]{geometry}
\usepackage{vwcol}
\makeatletter
\RenewEnviron{vwcol}[1][]{%
  \par\noindent
  \@vwcol@boxreadyfalse
  \vwcolsetup{#1}%
  \splittopskip=\ht\strutbox
  \expandafter\vwcol@process@widths\expandafter{\vwcol@widths}%
  \vwcol@para@setup
  \ifdim\vwcol@sep=1sp
    \vwcol@totalwidth=\linewidth
  \else
    \vwcol@totalwidth=\numexpr
      \vwcol@totalwidth+(\vwcol@Ncols-1)*\vwcol@sep
      \relax sp
    \if@vwcol@presep
      \advance\vwcol@totalwidth\dimexpr(\vwcol@sep-\vwcol@rule)/2\relax
    \fi
    \if@vwcol@postsep
      \advance\vwcol@totalwidth\dimexpr(\vwcol@sep-\vwcol@rule)/2\relax
    \fi
    \if@vwcol@prerule \advance\vwcol@totalwidth \vwcol@rule\fi
    \if@vwcol@postrule\advance\vwcol@totalwidth \vwcol@rule\fi
  \fi
  \ifdim\vwcol@totalwidth > \linewidth
    \vwcol@PackageWarning{%
      Total width of columns plus their separations
      is greater than the linewidth^^J\space\space
      (by \the\vwcol@totalwidth\space - \the\linewidth\space =
       \the\dimexpr \vwcol@totalwidth-\linewidth\relax)}%
  \fi
  \ifnum\vwcol@Nlines=0%
    \@tempcnta=\hbadness
    \hbadness=\maxdimen
    \gdef\footnotereset{exec}%%%% set flag to process footnotes at first run
    \setcounter{fntemp}{\value{footnote}}%%%% store initial footnote counter
    \setbox\vwcol@plainbox\hbox{%
      \parbox{\vwcol@averagewidth}{\vwcol@justify\BODY}}%
    \gdef\footnotereset{reset}%%%% don't process footnotes after first run
    \hbadness=\@tempcnta
    \vwcol@Nlines=\numexpr
        (\ht\vwcol@plainbox+\dp\vwcol@plainbox)/
        (\baselineskip*\vwcol@Ncols)
      \relax
    \@tempcnta=1%
    \loop\unless\if@vwcol@boxready
      \setcounter{footnote}{\value{fntemp}}%%%% reset counter for \footnotemark
      \savebox\vwcol@outputbox{%
        \hbox to \vwcol@totalwidth{\vwcol@{\BODY}}}%
      \unless\if@vwcol@boxready
        \advance\@tempcnta 1%
        \advance\vwcol@Nlines 1%
        \ifnum\@tempcnta>\vwcol@maxrecursion
          \@vwcol@boxreadytrue
          \vwcol@PackageError{%
            The estimated number of lines is greater than
            \the\vwcol@maxrecursion\space lines too small,%
              ^^J\space\space
            so I gave up (last tried maximum value of
            [lines=\the\vwcol@Nlines])%
          }{%
            Text will be truncated in the multicolumns;
            please select the%
            ^^J\space\space
            number of lines explicitly or increase
            [maxrecursion=\the\vwcol@maxrecursion].%
          }%
        \fi
      \fi
    \repeat
    \usebox\vwcol@outputbox
  \else
    \hbox to \vwcol@totalwidth{\vwcol@{\BODY}}%
    \unless\if@vwcol@boxready
      \vwcol@PackageError{%
        Not enough lines to fit the entire text;
        some text has been truncated.^^J\space\space
        Increase [lines=\the\vwcol@Nlines] to fit more%
      }{%
        Or remove [lines=\the\vwcol@Nlines] altogether
        to have 'vwcol' estimate the value.}%
    \fi
  \fi\par}

\def\fnexec{exec} % comparison value for \ifx
\newcounter{fntemp} % counter to store initial footnote number
\newcommand{\footnotevwc}[1]{%
% process footnotes if flag is set to 'exec', i.e., first run
% otherwise print only the mark (using the initial number)
\ifx\footnotereset\fnexec\footnote{#1}\else\footnotemark\fi%
}

% macros for showing footnotes outside of \parbox
\newcommand{\global@insert}[2]% #1=box number, #2=vertical list
{\bgroup
  \setbox\@tempboxa=\box#1
  \global\setbox#1=\vbox{\unvbox\@tempboxa #2}
\egroup}

\long\def\@footnotetext#1{\global@insert\footins{%
 \reset@font\footnotesize
 \interlinepenalty\interfootnotelinepenalty
 \splittopskip\footnotesep
 \splitmaxdepth \dp\strutbox \floatingpenalty \@MM
 \hsize\columnwidth \@parboxrestore
 \protected@edef\@currentlabel{%
 \csname p@footnote\endcsname\@thefnmark
 }%
 \color@begingroup
 \@makefntext{%
 \rule\z@\footnotesep\ignorespaces#1\@finalstrut\strutbox}%
 \color@endgroup}}%
\makeatother

\begin{document}
Footnote\footnote{before}
\begin{vwcol}[widths={.5,.5}, sep=.8cm, justify=flush]
Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Quisque mauris purus, rhoncus in scelerisque vitae, viverra ac quam.
Pellentesque habitant morbi tristique 
senectus\footnotevwc{et netus et malesuada fames ac turpis egestas}.
Duis in ligula sed massa aliquam accumsan.\footnotevwc{Aliquam erat volutpat.}
Donec nec lectus sit amet turpis pellentesque posuere vel a lorem.
Pellentesque laoreet nisl eu justo varius, quis pharetra ligula iaculis. 
\end{vwcol}
Footnote\footnote{after}
\end{document}

结果（注意，geometry使用了包来使页面变小）：

Answer 1