CTAN sync 202105070301

1 files changed, 101 insertions, 79 deletions

diff --git a/macros/latex/contrib/pbalance/pbalance.dtx b/macros/latex/contrib/pbalance/pbalance.dtx
index 63876d5293..ea00526085 100644
--- a/macros/latex/contrib/pbalance/pbalance.dtx
+++ b/macros/latex/contrib/pbalance/pbalance.dtx
@@ -1,8 +1,8 @@
 % \iffalse meta-comment
-% Copyright 2020 Nelson Lago <lago@ime.usp.br>
+% Copyright 2020-2021 Nelson Lago <lago@ime.usp.br>
 %
 % This work may be distributed and/or modified under the conditions of the
-% LaTeX Project Public License, either version 1.3 of this license or (at
+% LaTeX Project Public License, either version 1.3c of this license or (at
 % your option) any later version. The latest version of this license can be
 % found at http://www.latex-project.org/lppl.txt and version 1.3 or later
 % is part of all distributions of LaTeX version 2005/12/01 or later.
@@ -15,7 +15,7 @@
 % \iffalse
 %
 %<package>\NeedsTeXFormat{LaTeX2e}[2015/01/01]
-%<package>\ProvidesPackage{pbalance}[2020/12/16 v1.0.1 Poor man's balance]
+%<package>\ProvidesPackage{pbalance}[2021/04/26 v1.1.0 Poor man's balance]
 %
 %<*driver>
 
@@ -26,24 +26,15 @@
 \urlstyle{sf}
 \usepackage{hyperref}
 \hypersetup{
-  pdfborder={0 0 .6},
-  pdfborderstyle={/S/U/W .6},
-  urlbordercolor=DodgerBlue,
-  citebordercolor=White,
-  linkbordercolor=White,
-  filebordercolor=White,
+  colorlinks=true,
+  citecolor=DarkGreen,
+  linkcolor=NavyBlue,
+  urlcolor=DarkRed,
+  filecolor=green,
+  anchorcolor=black,
 }
 
 \usepackage[draft]{pbalance}
-\makeatletter
-\dimgdef\@PBtmpHeight{0pt}
-\dimgdef\@PBtmpLeftHeight{0pt}
-\dimgdef\@PBtmpLeftFloatsHeight{0pt}
-\dimgdef\@PBtmpRightHeight{0pt}
-\dimgdef\@PBtmpRightFloatsHeight{0pt}
-\dimgdef\@PBtmpUsedLeft{0pt}
-\dimgdef\@PBtmpUsedRight{0pt}
-\makeatother
 
 \usepackage{libertinus}
 \usepackage[scale=.85]{sourcecodepro}
@@ -66,6 +57,7 @@
 %
 % \changes{v1.0}{2020/09/14}{Initial version}
 % \changes{v1.0.1}{2020/12/16}{Improvements to documentation}
+% \changes{v1.1.0}{2021/04/26}{Do not crash in one-column mode}
 %
 % \GetFileInfo{pbalance.sty}
 %
@@ -131,13 +123,21 @@
 % need for extra passes during document preparation.
 %
 % If the last page does not have floats, footnotes, or marginpars, the
-% package simply uses \verb|\balance|, from the \texttt{balance} package;
+% package simply uses \verb|\balance|, from the \texttt{balance} package,
 % otherwise it uses its own algorithm. You may instead use
 % \verb|\shrinkLastPage{some-measurement}| to manually define how much
 % shorter the first column of the last page should be. This, however, will
 % not eliminate the need for extra passes (the package needs to find out
 % which page is the last).
 %
+% The package actually balances the last \emph{text} page; if the last
+% page is a float page, it is ignored. It also \emph{should} work if you
+% switch to single-column mode mid-document (with \verb|\onecolumn|); it
+% will then balance the last two-column text page. The same should happen
+% in a document that is mainly typeset in one column and you switch to
+% two-column layout (with \verb|\twocolumn|), but \emph{only} if the page
+% to be balanced does \emph{not} contain the \verb|\twocolumn| command.
+%
 % If there are many floats near the end of the document, the \LaTeX{}
 % float placement parameters (\verb|\topfraction|, \verb|topnumber|,
 % etc.) may interfere negatively with the algorithm. In some rare
@@ -171,12 +171,13 @@
 %
 % \begin{enumerate}
 %
-% \item It uses a \LaTeX{} pass to gather information: which is the last page?
-%       Does it have floats? Footnotes? How much free space in each column?
+% \item It uses a \LaTeX{} pass to gather information: which is the last
+%       two-column text page? Does it have floats? Footnotes? How much
+%       free space in each column?
 %
-% \item It uses this information in a subsequent pass to balance the last
+% \item It uses this information in a subsequent pass to balance that
 %       page. If there are no floats or footnotes, it uses the balance
-%       package; otherwise it uses the measurements collected to shrink
+%       package, otherwise it uses the measurements collected to shrink
 %       the first column (using \verb|\enlargethispage|) by a
 %       ``reasonable'' amount.
 %
@@ -198,10 +199,10 @@
 % To prevent this, it would be ideal to only start the process after all
 % passes needed to stabilize the document have run. In practice, however,
 % this would be too hard to detect (and demand even more passes). What
-% we do instead is simply wait for two consecutive passes to result
-% in columns of the same size in the last page. When this happens, we
-% proceed to balance in the next pass and assume (quite reasonably) that,
-% as long as the document is not modified, the effect of concurrent
+% we do instead is simply wait for two consecutive passes to result in
+% columns of the same size in the last two-column page. When this happens,
+% we proceed to balance in the next pass and assume (quite reasonably)
+% that, as long as the document is not modified, the effect of concurrent
 % changes during that pass in the last page is small, so ignoring it
 % disturbs the balancing only slightly\footnote{Like I said on the
 % introduction: this package is a hack.}.
@@ -212,9 +213,6 @@
 %
 % \begin{itemize}
 %
-%   \item add \verb|\if@twocolumn| tests to prevent crashes and
-%         other problems;
-%
 %   \item add options to (1) allow using the balance package on pages with
 %         floats and (2) completely disable the balance package;
 %
@@ -237,11 +235,12 @@
 % \section{The implementation}
 %
 % We define \verb|\@PBlastPage| using \texttt{zref-abspage}; It is the page
-% number for the last page of text. This might \emph{not} be the last page
-% of the document: there may be one or more float pages after it. Still,
-% it \emph{is} the page we want to balance. We do not act on it, however;
-% instead, we save its value to the aux file as \verb|\@PBprevLastPage| and
-% proceed to balance on the next \LaTeX{} pass.
+% number for the last two-column page of text. This might \emph{not} be the
+% last page of the document: there may be one or more float pages after it
+% or the user may have issued \verb|\onecolumn|. Still, it \emph{is} the page
+% we want to balance. We do not act on it, however; instead, we save its value
+% to the aux file as \verb|\@PBprevLastPage| and proceed to balance on the next
+% \LaTeX{} pass.
 %
 % We also define two toggles:
 %
@@ -320,7 +319,7 @@
     {#2}
     {
       % abspage refers to the finished page, not the nascent page
-      \ifnumcomp{\@PBprevLastPage - 1}{=}{\value{abspage}} 
+      \ifnumcomp{\@PBprevLastPage - 1}{=}{\value{abspage}}
         {#1}
         {#2}
     }
@@ -429,10 +428,10 @@
 % For the mechanism above to work, we need to know:
 %
 % \begin{enumerate}
-% \item The page number of the last page;
-% \item Whether the last page has floats, footnotes etc.;
-% \item The available height in the last page;
-% \item The height of the columns in the last page.
+% \item The page number of the last two-column text page;
+% \item Whether it has floats, footnotes etc.;
+% \item The available height in it;
+% \item The height of the columns in it.
 % \end{enumerate}
 %
 % Let's collect this info for every page.
@@ -601,25 +600,30 @@
 
 \ExplSyntaxOn
 \AtBeginShipout{
-  \ifboolexpr
-    {
-      % A float page is not the last text page, ignore
-      togl {@PBtmpIsFloatPage}
-      or
-      % A page with a float column on the left and an empty
-      % column on the right is not the last text page, ignore
-      (
-        togl {@PBtmpHasFloatcol}
-        and
-        test {\ifdimcomp{\@PBtmpUsedRight}{=}{\topskip}}
-      )
-    }
-    {}
-    {
-      % This page is a candidate to be the last page
-      \xdef\@PBlastPage{\the\value{abspage}}
-      \@PBcopyPageData{tmp}{candidate}
-    }
+  % It only makes sense to consider pages that actually have two
+  % columns. LaTeX3 does not do short-circuit evaluation, so we
+  % cannot add this test to the ifboolexpr below.
+  \if@twocolumn
+    \ifboolexpr
+      {
+        % A float page is not the last text page, ignore
+        togl {@PBtmpIsFloatPage}
+        or
+        % A page with a float column on the left and an empty
+        % column on the right is not the last text page, ignore
+        (
+          togl {@PBtmpHasFloatcol}
+          and
+          test {\ifdimcomp{\@PBtmpUsedRight}{=}{\topskip}}
+        )
+      }
+      {}
+      {
+        % This page is a candidate to be the last two-column text page
+        \xdef\@PBlastPage{\the\value{abspage}}
+        \@PBcopyPageData{tmp}{candidate}
+      }
+  \fi
 
     % Reset before processing next page
     \global\togglefalse{@PBtmpHasFloats}
@@ -635,8 +639,8 @@
 
 %    \end{macrocode}
 %
-% All pages processed, the last candidate page is actually the last page.
-% Instead of continuing to use the \texttt{@PBcandidate*} macros we already
+% All pages processed, the last candidate page is actually the last two-column
+% page. Instead of continuing to use the \texttt{@PBcandidate*} macros we already
 % have, we will keep the information we just gathered associated with the
 % page number. We do this because, in the future, we may want to add suport
 % for balancing multiple pages (such as the last page of each chapter) and
@@ -645,14 +649,20 @@
 %
 %    \begin{macrocode}
 
-\AfterLastShipout{\@PBcopyPageData{candidate}{pg\@Roman{\@PBlastPage}}}
+\AfterLastShipout{
+  % If there are no two-column pages in the
+  % document, there is no candidate page.
+  \ifcsdef{@PBlastPage}
+    {\@PBcopyPageData{candidate}{pg\@Roman{\@PBlastPage}}}
+    {}
+}
 
 %    \end{macrocode}
 %
 % \subsubsection{Saving measurements}
 % The whole document has already been processed and data about the last
-% page has been collected in macros with names \texttt{@PBpgNUM*}. We now
-% process this collected data and save whatever is relevant in the aux
+% two-column page has been collected in macros with names \texttt{@PBpgNUM*}.
+% We now process this collected data and save whatever is relevant in the aux
 % file for the next \LaTeX{} pass.
 %
 % In the first \LaTeX{} pass, we will save data to the aux file in macros
@@ -978,19 +988,25 @@
 
 \newcommand\@PBsaveUnbalancedInfo[1][]{
 
-  \immediate\write\@mainaux{\gdef\string\@PBprevLastPage{\@PBlastPage}}
-
-  \ifboolexpr{test {\ifdefvoid{\@PBprevLastPage}} or test {\ifstrequal{#1}{update}}}
-    % Columns are currently unbalanced, either because this is
-    % the first pass (we do not have any previous information)
-    % or because the document has not stabilized yet, so any
-    % previous information is unreliable. Save the information
-    % we just collected as ``unbalanced''.
-    {\@PBsavePageDataAs{pg\@Roman{\@PBlastPage}}{unbalpg\@Roman{\@PBlastPage}}}
-    % Not the first pass, so columns are possibly balanced;
-    % to save the unbalanced information, repeat what was
-    % gathered during the first pass.
-    {\@PBsavePageData{unbalpg\@Roman{\@PBprevLastPage}}}
+  % If there are no two-column pages in the
+  % document, there is nothing to save.
+  \ifcsdef{@PBlastPage}
+    {
+      \immediate\write\@mainaux{\gdef\string\@PBprevLastPage{\@PBlastPage}}
+
+      \ifboolexpr{test {\ifdefvoid{\@PBprevLastPage}} or test {\ifstrequal{#1}{update}}}
+        % Columns are currently unbalanced, either because this is
+        % the first pass (we do not have any previous information)
+        % or because the document has not stabilized yet, so any
+        % previous information is unreliable. Save the information
+        % we just collected as ``unbalanced''.
+        {\@PBsavePageDataAs{pg\@Roman{\@PBlastPage}}{unbalpg\@Roman{\@PBlastPage}}}
+        % Not the first pass, so columns are possibly balanced;
+        % to save the unbalanced information, repeat what was
+        % gathered during the first pass.
+        {\@PBsavePageData{unbalpg\@Roman{\@PBprevLastPage}}}
+    }
+    {}
 }
 
 \def\@PBsaveBalancedInfo{
@@ -1002,8 +1018,14 @@
 
 \def\@PBnotifyRerun{
   \AtVeryEndDocument{
-    \PackageWarningNoLine{pbalance}
-    {Last page columns not balanced. Rerun LaTeX}
+    % If there are no two-column pages in the document,
+    % it makes no sense to emit this warning.
+    \ifcsdef{@PBlastPage}
+      {
+        \PackageWarningNoLine{pbalance}
+        {Last two-column page cols not balanced. Rerun LaTeX}
+      }
+      {}
   }
 }