From 042d4edb85997e17a0b71f0f584e7c6371b2bf39 Mon Sep 17 00:00:00 2001 From: Norbert Preining Date: Sat, 5 Dec 2020 03:00:47 +0000 Subject: CTAN sync 202012050300 --- macros/latex/contrib/pbalance/LICENSE | 11 + macros/latex/contrib/pbalance/README.md | 14 + macros/latex/contrib/pbalance/pbalance.dtx | 1069 ++++++++++++++++++++++++++++ macros/latex/contrib/pbalance/pbalance.ins | 49 ++ macros/latex/contrib/pbalance/pbalance.pdf | Bin 0 -> 307144 bytes 5 files changed, 1143 insertions(+) create mode 100644 macros/latex/contrib/pbalance/LICENSE create mode 100644 macros/latex/contrib/pbalance/README.md create mode 100644 macros/latex/contrib/pbalance/pbalance.dtx create mode 100644 macros/latex/contrib/pbalance/pbalance.ins create mode 100644 macros/latex/contrib/pbalance/pbalance.pdf (limited to 'macros/latex/contrib/pbalance') diff --git a/macros/latex/contrib/pbalance/LICENSE b/macros/latex/contrib/pbalance/LICENSE new file mode 100644 index 0000000000..dea471c70c --- /dev/null +++ b/macros/latex/contrib/pbalance/LICENSE @@ -0,0 +1,11 @@ +Copyright 2020 Nelson Lago + +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 +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. + +This work has the LPPL maintenance status `maintained'. + +The Current Maintainer of this work is Nelson Lago . diff --git a/macros/latex/contrib/pbalance/README.md b/macros/latex/contrib/pbalance/README.md new file mode 100644 index 0000000000..6ac43ea0c8 --- /dev/null +++ b/macros/latex/contrib/pbalance/README.md @@ -0,0 +1,14 @@ +# pbalance - poor man's balance package for LaTeX + +This is a LaTeX package that tries to *safely* make the columns on the last +page of a two-column document have approximately the same height. It should +"just work" without user intervention, which is particularly useful for +class authors, but also offers the user a command to control the result. +There are, however, three caveats: + +1. Results are adequate, but often not optimal; +2. In some cases, the package may give up (the document is + generated correctly but the last page is not balanced); +3. The package demands additional LaTeX passes. + +Code etc: diff --git a/macros/latex/contrib/pbalance/pbalance.dtx b/macros/latex/contrib/pbalance/pbalance.dtx new file mode 100644 index 0000000000..e63bee62a9 --- /dev/null +++ b/macros/latex/contrib/pbalance/pbalance.dtx @@ -0,0 +1,1069 @@ +% \iffalse meta-comment +% Copyright 2020 Nelson Lago +% +% 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 +% 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. +% +% This work has the LPPL maintenance status `maintained'. +% +% The Current Maintainer of this work is Nelson Lago . +% +% \fi +% \iffalse +% +%\NeedsTeXFormat{LaTeX2e}[2015/01/01] +%\ProvidesPackage{pbalance}[2020/12/03 v1.0 Poor man's balance] +% +%<*driver> + +\documentclass{ltxdoc} + +\usepackage[hyperref,svgnames,x11names,table]{xcolor} +\usepackage{url} +\urlstyle{sf} +\usepackage{hyperref} +\hypersetup{ + pdfborder={0 0 .6}, + pdfborderstyle={/S/U/W .6}, + urlbordercolor=DodgerBlue, + citebordercolor=White, + linkbordercolor=White, + filebordercolor=White, +} + +\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} + +%%\EnableCrossrefs +%%\CodelineIndex +%%\RecordChanges + +%%\OnlyDescription + +\begin{document} +\DocInput{pbalance.dtx} +\end{document} + +% +% +% \fi +% +% \CheckSum{0} +% +% \changes{v1.0}{2020/09/14}{Initial version} +% +% \GetFileInfo{pbalance.sty} +% +% \title{The \textsf{pbalance} (poor man's balance) package\thanks{This +% document corresponds to \textsf{pbalance}~\fileversion, dated~\filedate.}} +% +% \author{ +% Nelson Lago\\ +% \texttt{lago@ime.usp.br}\\ +% ~\\ +% \url{https://gitlab.com/lago/pbalance} +%} +% +% \maketitle +% +% \begin{abstract} +% +% This package tries to \emph{safely} make the columns on the last page +% of a two-column document have approximately the same height. It should +% ``just work'' without user intervention, which is particularly useful +% for class authors, but also offers the user a command to control the +% result. There are, however, three caveats: +% +% \begin{enumerate} +% \item Results are adequate, but often not optimal; +% \item In some cases, the package may give up (the document is +% generated correctly but the last page is not balanced); +% \item The package demands additional \LaTeX{} passes. +% \end{enumerate} +% +% \end{abstract} +% +% \section{Introduction and usage} +% +% First things first: this package is a \textbf{hack}. It is also +% \textbf{beta} quality. However, I believe it is \emph{safe}, +% i.e., it should not generate incorrect output. +% +% In a two-column document, it is desirable for the columns in the last +% page to have the same height (the columns should be ``balanced''). Two +% packages (\texttt{balance} and \texttt{flushend}) try to provide this +% in \LaTeX, but both may generate defective output in some circumstances. +% This package tries to solve this problem. +% +% Balancing is often not possible: imagine a document with an odd number +% of lines on the last page, or with ten lines of text together with an +% image that takes the height of fifteen lines of text, or a document where +% making columns the same height would leave a sectioning comand at the +% bottom of the first column etc. Since such cases happen often, we consider +% it enough for the columns to be ``not too unequal'', even when equal +% heights might be possible (the algorithm cannot deliver better results +% and, in fact, striving to make columns exactly the same height with it +% may sometimes yield poor results, so we do not even try). +% +% To use the package, add \verb|\usepackage{pbalance}| to the preamble +% and things should ``just work''. However, the document will take more +% \LaTeX{} passes to compile, and minute changes to it that would normally +% need one additional \LaTeX{} pass will likely need three. +% +% If the last page does not have floats, footnotes, or marginpars, the +% 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). +% +% \section{How does it work} +% +% This package works on two fronts: +% +% \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 this information in a subsequent pass to balance the last +% page. If there are no floats or footnotes, it uses the balance +% package; otherwise it uses the measurements collected to shrink +% the first column (using \verb|\enlargethispage|) by a +% ``reasonable'' amount. +% +% \end{enumerate} +% +% If measurements change between passes, this means the document was +% edited, so we forget the previously gathered data and start over. +% However, the package cannot detect changes that happen between the +% ``collect data'' pass and the ``balance for the first time'' pass: +% it has to assume that any change at this point is caused by the fact +% that we started balancing (it can, however, detect if the last text +% page changed; if this happens, we give up balancing). If the change is +% small, that is acceptable: we are not aiming at balancing perfectly +% anyway. If it is a big change (for example, the addition of the +% bibliography block), results will suffer. +% +% 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. 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 further passes 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.}. +% +% \section{TODO / wish list} +% +% Some useful stuff we should consider implementing: +% +% \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; +% +% \item make the mechanism able to work with any page, not just the last, +% and with more than one page at once. This is useful for book +% chapters, for example; +% +% \item on top of that: +% \begin{enumerate} +% \item create command to manually indicate the page numbers to balance +% \item create command similar to \verb|\balance| from the +% \texttt{balance} package +% \item allow user to set manual balancing for each page independently +% \end{enumerate} +% +% \end{itemize} +% +% \StopEventually{} +% +% \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. +% +% We also define two toggles: +% +% \begin{description} +% \item[\texttt{@PBstabilized}] There have been a few passes +% already and the document has apparently stabilized. +% \item[\texttt{@PBimpossible}] We tried to balance on a +% previous pass and failed. +% \end{description} +% +% \subsection{Initialization, required packages etc.} +% +% Besides some other required packages, here we load the \texttt{balance} +% package; if there are no floats or footnotes involved, we will simply use +% it. We need to load it after we modify \verb|\@outputdblcol|, so we use +% \verb|\AtEndOfPackage|. +% +% We also define the \texttt{draft} option, which disables processing. +% +% \begin{macrocode} + +\RequirePackage{etoolbox} +\RequirePackage{expl3} +\RequirePackage{atbegshi} % Manipulate the page output routine +\RequirePackage{atveryend} % Write to the aux file after processing ends +\RequirePackage{zref-abspage} % Figure out the current page + +\AtEndOfPackage{\RequirePackage{balance}} + +% See https://github.com/latex3/latex2e/issues/399#issuecomment-703081793 +\gdef \@reinserts{% + \ifvbox\@kludgeins\insert\@kludgeins + {\unvbox\@kludgeins}\fi + \ifvoid\footins\else\insert\footins{\unvbox\footins}\fi +} + +\providetoggle{@PBstabilized} +\providetoggle{@PBimpossible} + +\newtoggle{@PBdraft} +\DeclareOption{draft}{\toggletrue{@PBdraft}} +\ProcessOptions\relax + +% \end{macrocode} + +% \subsection{The balancing front} +% +% The basic balancing process is reasonably simple: right before each +% new page, check whether it should be balanced. If so, add the adequate +% code to the top of the page (either call \verb|\balance|, from the +% \texttt{balance} package, or add \verb|\enlargethispage|). +% +% \begin{macrocode} + +% Right before the first page +\AtBeginDocument{ + \@PBifShouldBalanceNascentPage + {\@PBStartBalancing} + {} +} + +% Right before all other pages +\AtBeginShipout{ + \@PBifShouldBalanceNascentPage + {\@PBStartBalancing} + {} +} + +\newcommand\@PBifShouldBalanceNascentPage[2]{ + \ifboolexpr + { + togl {@PBdraft} + or not togl {@PBstabilized} + or test {\ifdefvoid{\@PBprevLastPage}} + } + {#2} + { + % abspage refers to the finished page, not the nascent page + \ifnumcomp{\@PBprevLastPage - 1}{=}{\value{abspage}} + {#1} + {#2} + } +} + +% Let's give the user a chance to manually define what to do +\newcommand\shrinkLastPage[1]{\dimgdef\@PBslack{#1}} + +\newcommand\@PBStartBalancing{ + \ifdefvoid{\@PBslack} + {\@PBautomaticBalance} + {\@PBshrinkPage} +} + +\newcommand\@PBautomaticBalance{ + \@PBifBalancePossible + { + \@PBifBalancePkgPossible + {\balance} % easy peasy, use the balance package + { + \@PBifPoorBalancePossible + { + % use the poor man's balance algorithm + \@PBcalculateShrinkage + \@PBshrinkPage + } + {} + } + } + {} +} + +% Calculate how much we should shrink the left column of the last +% page based on the measurements we took on previous LaTeX passes. +\newcommand\@PBcalculateShrinkage{ + + % Let's use some shorter names, please + \dimdef\@PBtmpH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}Height}} + \dimdef\@PBtmpUL{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}UsedLeft}} + \dimdef\@PBtmpUR{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}UsedRight}} + + \dimdef\@PBtmpLH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}LeftHeight}} + \dimdef\@PBtmpLFH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}LeftFloatsHeight}} + \dimdef\@PBtmpRH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}RightHeight}} + \dimdef\@PBtmpRFH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}RightFloatsHeight}} + + % Figure out the amount of unused space on the last page (both + % cols); we will reduce the first column height by half that amount + \dimgdef\@PBslack{2\dimexpr\@PBtmpH\relax - \@PBtmpUL - \@PBtmpUR} + \dimgdef\@PBslack{.5\dimexpr\@PBslack\relax} + + % Actually, I lied. While half, as said above, sometimes yields + % perfectly balanced columns, that is often not the case (the page + % may have an odd number of lines, or textheight may not be a + % multiple of baselineskip, or there may be glues etc.). Sometimes + % the difference is very small, less than a line, which does not + % look good at all, and sometimes the right column is slightly + % higher than the left, which is also not ideal. Here, we force + % the left column to always be somewhat taller than the left; the + % result is often ``better''. + \dimgdef\@PBslack{\@PBslack - 1.5\baselineskip} + + % If necessary, reduce @PBslack to prevent LaTeX from adding a page + \@PBsafetyCheck +} + +\def\@PBshrinkPage{ + % Zero obviously means ``do nothing''. We could + % ``enlarge'' by 0, but IDK, maybe that would + % trigger another LaTeX pass or something. + \ifdimcomp{\@PBslack}{=}{0pt} + {} + { + % Shrink the first column + \enlargethispage{-\@PBslack} + + % Modify the behavior of \@outputdblcol + % to raise footnotes in the second column. + \global\let\@PBbalanceSecondColumn\@PBrealBalanceSecondColumn + } +} + +% If there are footnotes on the right column, it is better to +% ``push'' them up to be aligned with the end of the left column, +% especially if there are footnotes on the left column too. We +% do this by manipulating \@textbottom in \@outputdblcol. +\pretocmd{\@outputdblcol}{\@PBbalanceSecondColumn}{}{} + +\let\@PBbalanceSecondColumn\relax + +\def\@PBrealBalanceSecondColumn{ + \if@firstcolumn + % Affects the next column + \global\let\@PBorigtextbottom\@textbottom + \gdef\@textbottom{\vskip \@PBslack plus .0001fil minus 10000fill\relax \@PBorigtextbottom} + \else + % Back to normal before starting the next page + \global\let\@textbottom\@PBorigtextbottom + \global\let\@PBbalanceSecondColumn\relax + \fi +} + +% \end{macrocode} + +% \subsection{The measuring front} +% 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. +% \end{enumerate} +% +% Let's collect this info for every page. +% +% \subsubsection{Are there floats, footnotes, or marginpars in the last page?} +% +% \begin{macrocode} + +% To check whether there are floats etc. in the last page, +% we will copy the fancyhdr package: +% https://tex.stackexchange.com/questions/56673/is-there-a-way-to-determine-if-there-is-a-float-on-a-page +% But we add the tests to a different place. +\newcommand\@PBifmidfloat[2]{\ifx\@midlist\empty #2\else #1\fi} +\newcommand\@PBiftopfloat[2]{\ifx\@toplist\empty #2\else #1\fi} +\newcommand\@PBifbotfloat[2]{\ifx\@botlist\empty #2\else #1\fi} +\newcommand\@PBiffootnote[2]{\ifvoid\footins #2\else #1\fi} +\newcommand\@PBiffloatcol[2]{\if@fcolmade #1\else #2\fi} +% dbltop floats are apparently ok with the balance package +%%%\newcommand\@PBifdbltopfloat[2]{\ifx\@dbltoplist\empty #2\else #1\fi} +% dblbotlist only exists with package stfloats +\newcommand\@PBifdblbotfloat[2]{% + \ifdefvoid{\@dblbotlist} + {#2} + {\ifx\@dblbotlist\empty #2\else #1\fi}% +} + +% If there are footnotes, floats or marginpars in +% the page, we should not use the balance package +\newtoggle{@PBtmpHasFootnotes} +\newtoggle{@PBtmpHasFloats} +\newtoggle{@PBtmpHasMarginpars} + +\def\@PBcollectPageInfo{ + + \ifboolexpr + { + test {\@PBifmidfloat} or test {\@PBiftopfloat} or + test {\@PBifbotfloat} or test {\@PBifdblbotfloat} + } + {\global\toggletrue{@PBtmpHasFloats}} + {} + + \@PBiffootnote + {\global\toggletrue{@PBtmpHasFootnotes}} + {} +} + +\pretocmd{\@makecol}{\@PBcollectPageInfo}{}{} + +% This only gets called if there is a marginpar, so that's easy +\pretocmd{\@addmarginpar}{\global\toggletrue{@PBtmpHasMarginpars}}{}{} + +% \end{macrocode} +% +% \subsubsection{What are the sizes of the floats in the left column?} +% +% \begin{macrocode} + +\ExplSyntaxOn +\seq_gclear_new:N \@PBtmpLeftFloatHeights +\seq_gclear_new:N \@PBtmpLeftFloatSpacesBelow +\def\@PBcollectFloatHeights{ + \if@firstcolumn + \dimdef\@PBfloatHeight{\@textfloatsheight - \@PBtmpHeightBefore} + \ifdimcomp{\@PBfloatHeight}{>}{0pt} + { + \global\seq_put_right:NV \@PBtmpLeftFloatHeights \@PBfloatHeight + + \dimdef\@PBspaceBelow{\@colroom - \@pageht - \@PBfloatHeight} + % within \@addtocurcol, \@pageht corresponds to all + % currently used space in the column, including footnotes + % (check \@specialoutput in the LaTeX kernel). Let's + % exclude the footnotes, we only want the space below + % the float. + \ifvoid\footins\else + \dimdef\@PBspaceBelow{\@PBspaceBelow + \ht\footins + \skip\footins + \dp\footins} + \fi + + % No idea why, but this can happen; maybe because of the page depth? + \ifdimcomp{\@PBspaceBelow}{<}{0pt} + {\dimdef\@PBspaceBelow{0pt}} + {} + + \global\seq_put_right:NV \@PBtmpLeftFloatSpacesBelow \@PBspaceBelow + } + {} + \fi +} +\ExplSyntaxOff + +\pretocmd{\@addtocurcol}{\dimgdef{\@PBtmpHeightBefore}{\@textfloatsheight}}{}{} +\apptocmd{\@addtocurcol}{\@PBcollectFloatHeights}{}{} + +% \end{macrocode} +% +% \subsubsection{What is the size of each column? Is there a float column / floatpage?} +% +% \begin{macrocode} + +% If there is a float column in the page, it makes no sense to try to +% balance; if both columns are float columns, this page cannot be the +% final text page, i.e., we want to balance some other page. +\newtoggle{@PBtmpHasFloatcol} +\newtoggle{@PBtmpIsFloatPage} + +\newcommand\@PBcollectColumnInfo{ + + \if@firstcolumn + + \@PBiffloatcol + {\global\toggletrue{@PBtmpHasFloatcol}} + {} + + % Available vertical space excluding + % dblfloats; the same for both columns + \dimgdef\@PBtmpHeight{\@colht} + + % Available vertical space excluding top/bottom floats + \dimgdef\@PBtmpLeftHeight{\@colroom} + + % Space used by \texttt{here} floats + \dimgdef\@PBtmpLeftFloatsHeight{\@textfloatsheight} + + \else + + \@PBiffloatcol + { + \iftoggle{@PBtmpHasFloatcol} + {\global\toggletrue{@PBtmpIsFloatPage}} + {\global\toggletrue{@PBtmpHasFloatcol}} + } + {} + + \dimgdef\@PBtmpRightHeight{\@colroom} + \dimgdef\@PBtmpRightFloatsHeight{\@textfloatsheight} + + \setbox\@tempboxa=\copy\@leftcolumn + \setbox\@tempboxa=\vbox{\unvbox\@tempboxa\unskip\unskip} + \dimgdef\@PBtmpUsedLeft{\ht\@tempboxa\relax} + + \setbox\@tempboxa=\copy\@outputbox + \setbox\@tempboxa=\vbox{\unvbox\@tempboxa\unskip\unskip} + \dimgdef\@PBtmpUsedRight{\ht\@tempboxa\relax} + \fi +} + +% The default LaTeX macro +\pretocmd{\@outputdblcol}{\@PBcollectColumnInfo}{}{} + +% The version from the balance package +\AtEndOfPackage{ + \pretocmd{\@BAdblcol}{\@PBcollectColumnInfo}{}{} + % Revert \balance before next page if it exists (it might be a float page) + \patchcmd{\@BAdblcol}{\endgroup}{\endgroup\nobalance}{}{} +} + +% \end{macrocode} +% +% \subsubsection{Analyze the obtained information} +% +% We have inserted the hooks we need to collect data during +% the processing of each page and column. Now we inspect the +% collected data after each page is finalized. +% +% \begin{macrocode} + +\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} + } + + % Reset before processing next page + \global\togglefalse{@PBtmpHasFloats} + \global\togglefalse{@PBtmpHasFloatcol} + \global\togglefalse{@PBtmpHasFootnotes} + \global\togglefalse{@PBtmpHasMarginpars} + \global\togglefalse{@PBtmpIsFloatPage} + + \seq_gclear_new:N \@PBtmpLeftFloatHeights + \seq_gclear_new:N \@PBtmpLeftFloatSpacesBelow +} +\ExplSyntaxOff + +% \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 +% 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 +% not only the last one. This also makes it easier to handle the situation +% where the document was modified and the last page has changed. +% +% \begin{macrocode} + +\AfterLastShipout{\@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 +% file for the next \LaTeX{} pass. +% +% In the first \LaTeX{} pass, we will save data to the aux file in macros +% with names \texttt{@PBunbalpgNUM*}. That is all we need for balancing. +% However, to detect whether the document has changed and, therefore, +% whether we should re-balance, we will also record the same data after +% balancing (during the second pass) in macros with names +% \texttt{@PBbalpgNUM*}. If, in the third or later \LaTeX{} passes, +% \texttt{@PBbalpgNUM*} differ from \texttt{@PBpgNUM*}, the document +% has been changed and we need to re-balance. +% +% So, we have: +% +% \begin{description} +% \item[\texttt{@PBpgNUM*}] data collected during the current pass; +% \item[\texttt{@PBunbalpgNUM*}] data collected in the first pass; +% \item[\texttt{@PBbalpgNUM*}] data collected in the second pass (after +% balancing); in subsequent passes, these should always be equal +% to \texttt{@PBpgNUM*}. +% \end{description} +% +% The last two are saved to / read from the aux file. +% +% \begin{macrocode} + +% Make sure the document has stabilized before using \@PBmanageBalancingPasses +\AfterLastShipout{ + % Reset \@PBimpossible if we are in draft mode, + % so the user can start over if they want to. + \iftoggle{@PBdraft}{\togglefalse{@PBimpossible}}{} + + \ifboolexpr{togl {@PBdraft} or togl {@PBimpossible}} + {} + { + \ifdefvoid{\@PBprevLastPage} + {\@PBsaveUnbalancedInfo\@PBnotifyRerun} % First pass + { + \iftoggle{@PBstabilized} + {\@PBmanageBalancingPasses} + { + \@PBifSomethingChanged[unbal] + % Document still changing; discard data from previous pass + {\@PBsaveUnbalancedInfo[update]\@PBnotifyRerun} + % No changes, so let's balance from now on (once @PBstabilized + % becomes true, it never reverts back to false, unless the aux + % file is deleted). + {\toggletrue{@PBstabilized}\@PBsaveUnbalancedInfo\@PBnotifyRerun} + } + } + \@PBsaveToggle{@PBstabilized} + } + + \@PBsaveToggle{@PBimpossible} + \immediate\write\@mainaux{\gdef\string\@PBprevLastPhysPage{\the\value{abspage}}} +} + +\newcommand\@PBmanageBalancingPasses{ + % This is the second pass or later after we started balancing + + \providetoggle{@PBpg\@Roman{\@PBlastPage}alreadyBalanced} + + \iftoggle{@PBpg\@Roman{\@PBlastPage}alreadyBalanced} + { + % Third pass or later; document was already + % balanced, so there should be no more changes + \@PBifSomethingChanged + % The document has changed, so we need to measure + % stuff again; clear aux file and start over. + {\@PBnotifyRerun} + % Nothing changed, just write the same info down + {\@PBsaveUnbalancedInfo\@PBsaveBalancedInfo} + } + % Second pass, which means something did change: we have just + % balanced the columns for the first time. + { + \xdef\@tempa{\the\value{abspage}} + \ifboolexpr + { + test {\ifdefstrequal{\@PBprevLastPage}{\@PBlastPage}} + and + test {\ifdefstrequal{\@PBprevLastPhysPage}{\@tempa}} + } + % All is well; save the new info + {\@PBsaveUnbalancedInfo\@PBsaveBalancedInfo} + % Oh, no! As we attempted to balance, we actually changed + % the number of pages (maybe we added a float page, maybe + % we turned the last float page into a text page etc.). If + % we continue, the document might never converge (endless + % ``please rerun LaTeX'' messages). Let's give up balancing. + {\toggletrue{@PBimpossible}} + } +} + +% \end{macrocode} +% +% \subsection{Auxiliary macros} +% +% \begin{macrocode} + +\newcommand\@PBifBalancePossible[2]{ + \iftoggle{@PBunbalpg\@Roman{\@PBprevLastPage}HasFloatcol} + {#2} + {#1} +} + +% The balance package may fail badly in the presence of footnotes: +% they may end up in the middle of the text. Marginpars may end up +% on the wrong side of the page. Floats are usually ok, but in some +% cases the columns may become very badly balanced. For ordinary +% text, it works perfectly. +\newcommand\@PBifBalancePkgPossible[2]{ + \ifboolexpr + { + togl {@PBunbalpg\@Roman{\@PBprevLastPage}HasFloats} + or + togl {@PBunbalpg\@Roman{\@PBprevLastPage}HasFootnotes} + or + togl {@PBunbalpg\@Roman{\@PBprevLastPage}HasMarginpars} + } + {#2} + {#1} +} + +% \end{macrocode} +% +% We only want to balance if: +% +% \begin{enumerate} +% +% \item The left column is higher than the right one. If that is not the +% case, either things are already balanced or the right column is +% higher, which means \LaTeX{} was forced into a bad solution already. +% +% \item This difference is ``large enough'' (6 lines), which means two things: +% \begin{enumerate} +% +% \item There will be an actual improvement in the result. +% +% \item There is plenty of free space on the right column, so even if +% our changes happen to take more space than before, \LaTeX{} will +% hopefully not add a new page (but it might make the right +% column higher than the left, which is not so great). +% \end{enumerate} +% +% \end{enumerate} +% +% If there is material only on the left column, we want to balance even +% if the difference in height is not ``large enough'', as long as there +% are more than 4 lines to split among columns. This is actually quite +% unlikely: if there is so little material, the page probably has only +% normal text and we will use the balance package. +% +% \begin{macrocode} + +\newcommand\@PBifPoorBalancePossible[2]{ + + % Let's use some shorter names, please + \dimdef\@PBtmpH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}Height}} + \dimdef\@PBtmpUL{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}UsedLeft}} + \dimdef\@PBtmpUR{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}UsedRight}} + + \dimdef\@PBtmpLH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}LeftHeight}} + \dimdef\@PBtmpLFH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}LeftFloatsHeight}} + \dimdef\@PBtmpRH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}RightHeight}} + \dimdef\@PBtmpRFH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}RightFloatsHeight}} + + \ifboolexpr{ + % Plenty of space on right column, difference is worth it + test {\ifdimcomp{\@PBtmpUL}{>}{\@PBtmpUR + 6\baselineskip}} + or + ( + test {\ifdimcomp{\@PBtmpUL}{>}{4\baselineskip}} + and + test {\ifdimcomp{\@PBtmpUR}{=}{\topskip}} % column is empty + ) + }{#1}{#2} +} + +% \end{macrocode} +% +% If there are floats, things can get messy: imagine that we want to +% shrink by 50pt, but there is a 250pt float near the end of the left +% column that won't fit after we shrink, so it will move to the right. +% What if there is no room for such a large float there? Here, we try +% to prevent this situation and shrink by a smaller amount if there +% is a float that won't fit. Note that, if the float goes to the +% right column, there will be more room for text in the left column. +% Therefore, a float will not fit only if the floats on the right +% column take too much space. So, what we do here is, starting from +% the bottom, check whether the accumulated height of the floats +% from the left column fit in the right. If we find a float that +% will not fit, we know that we should limit shrinking to the space +% below that float. +% +% In the same vein, we do not want top/bottom floats from the left +% column that were deferred from a previous page to be pushed to +% the right column. To that end, we limit the shrinking amount to +% the space on the left column not taken by top/bottom floats. + +% \textbf{TODO:} Top and bottom floats may appear in two cases: (1) they +% were generated on a previous page and deferred or (2) the user +% chose placement options \texttt{t} or \texttt{b}, without +% \texttt{h}. Deferred floats are not a problem: we do not reduce +% the space available for top/bottom floats, so they should +% continue to fit. Floats on the left column with placement +% options \texttt{t} and \texttt{b} without \texttt{h} can be +% a problem: \LaTeX{} only considers putting a float on the +% top/bottom of the current column if, at the point of its +% definition, there is enough space for it. Since we are shrinking +% the column, it may not fit and be deferred - something the +% algorithm does not take into consideration. However, not all is +% lost: most likely, the user will only use such placement +% options when trying to manually adjust the page, which +% means they will be able to detect and work around eventual +% problems. +% +% \begin{macrocode} + +\ExplSyntaxOn +\def\@PBsafetyCheck{ + + % Let's use some shorter names, please + \dimdef\@PBtmpH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}Height}} + \dimdef\@PBtmpUL{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}UsedLeft}} + \dimdef\@PBtmpUR{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}UsedRight}} + + \dimdef\@PBtmpLH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}LeftHeight}} + \dimdef\@PBtmpLFH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}LeftFloatsHeight}} + \dimdef\@PBtmpRH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}RightHeight}} + \dimdef\@PBtmpRFH{\csuse{@PBunbalpg\@Roman{\@PBprevLastPage}RightFloatsHeight}} + + + % Make sure we do not push top/bottom floats out of the left col + \dimdef\@PBmaxSlack{\@PBtmpLH} + + \dimdef\@PBtmpdim{0pt} + + % Start from the bottom + \numdef{\@PBtmpcnt}{\seq_count:c {@PBunbalpg\@Roman{\@PBprevLastPage}LeftFloatHeights}} + \int_while_do:nNnn {\@PBtmpcnt} > {0} + { + + \dimdef\@PBcurrentFloatHeight + {\seq_item:cn {@PBunbalpg\@Roman{\@PBprevLastPage}LeftFloatHeights} {\@PBtmpcnt}} + + \dimdef\@PBcurrentFloatSpaceBelow + {\seq_item:cn {@PBunbalpg\@Roman{\@PBprevLastPage}LeftFloatSpacesBelow} {\@PBtmpcnt}} + + \dimdef{\@PBtmpdim}{\@PBtmpdim + \@PBcurrentFloatHeight} + + \ifboolexpr + { + % Does the float fit in the second column? + test {\ifdimcomp{\@PBtmpdim}{<}{\@PBtmpRH - \@PBtmpRFH}} + and + % Is there something above this float, i.e., if we move + % this float to the next column, will anything remain? + test + { + \ifdimcomp + {\@PBcurrentFloatSpaceBelow + \@PBcurrentFloatHeight} + {<} + {\@PBtmpLH - 6\baselineskip} + } + } + {\numdef{\@PBtmpcnt}{\@PBtmpcnt - 1}} % this one is ok; check next + { + % this one should not be moved, we found the limit + \ifdimcomp{\@PBmaxSlack}{>}{\@PBcurrentFloatSpaceBelow} + {\dimdef{\@PBmaxSlack}{\@PBcurrentFloatSpaceBelow}} + {} + \numdef{\@PBtmpcnt}{0} % exit the loop + } + } + + \ifdimcomp{\@PBmaxSlack}{<}{\@PBslack} + {\dimgdef{\@PBslack}{\@PBmaxSlack}} + {} +} +\ExplSyntaxOff + +% Compare current measurements with previous ``bal'' or ``unbal'' measurements +\newcommand\@PBifSomethingChanged[3][bal]{ + \ifdefstrequal{\@PBprevLastPage}{\@PBlastPage} + { + \@PBifPageDataMatches + {pg\@Roman{\@PBlastPage}} + {#1pg\@Roman{\@PBlastPage}} + {#3} + {#2} + } + {#2} +} + +\newcommand\@PBifPageDataMatches[4]{ + \ifboolexpr{ + test {\@PBifTogglesMatch{@PB#1HasFloats}{@PB#2HasFloats}} + and test {\@PBifTogglesMatch{@PB#1HasFloatcol}{@PB#2HasFloatcol}} + and test {\@PBifTogglesMatch{@PB#1HasFootnotes}{@PB#2HasFootnotes}} + and test {\@PBifTogglesMatch{@PB#1HasMarginpars}{@PB#2HasMarginpars}} + and test {\@PBifDimensionsMatch{@PB#1Height}{@PB#2Height}} + and test {\@PBifDimensionsMatch{@PB#1LeftHeight}{@PB#2LeftHeight}} + and test {\@PBifDimensionsMatch{@PB#1RightHeight}{@PB#2RightHeight}} + and test {\@PBifDimensionsMatch{@PB#1UsedLeft}{@PB#2UsedLeft}} + and test {\@PBifDimensionsMatch{@PB#1UsedRight}{@PB#2UsedRight}} + } + {#3} + {#4} +} + +% https://en.wikipedia.org/wiki/XNOR_gate +\newcommand\@PBifTogglesMatch[4]{ + \ifboolexpr{(togl{#1} or not togl{#2}) and (togl{#2} or not togl{#1})} + {#3} + {#4} +} + +\newcommand\@PBifDimensionsMatch[4]{ + \ifdimcomp{\csuse{#1}}{=}{\csuse{#2}} + {#3} + {#4} +} + +\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}}} +} + +\def\@PBsaveBalancedInfo{ + \global\toggletrue{@PBpg\@Roman{\@PBlastPage}alreadyBalanced} + \@PBsaveToggle{@PBpg\@Roman{\@PBlastPage}alreadyBalanced} + + \@PBsavePageDataAs{pg\@Roman{\@PBlastPage}}{balpg\@Roman{\@PBlastPage}} +} + +\def\@PBnotifyRerun{ + \AtVeryEndDocument{ + \PackageWarningNoLine{pbalance} + {Last page columns not balanced. Rerun LaTeX} + } +} + +\ExplSyntaxOn +\newcommand\@PBcopyPageData[2]{ + + \global\providetoggle{@PB#2HasFloats} + \global\providetoggle{@PB#2HasFloatcol} + \global\providetoggle{@PB#2HasFootnotes} + \global\providetoggle{@PB#2HasMarginpars} + + \iftoggle{@PB#1HasFloats} + {\global\toggletrue{@PB#2HasFloats}} + {\global\togglefalse{@PB#2HasFloats}} + + \iftoggle{@PB#1HasFloatcol} + {\global\toggletrue{@PB#2HasFloatcol}} + {\global\togglefalse{@PB#2HasFloatcol}} + + \iftoggle{@PB#1HasFootnotes} + {\global\toggletrue{@PB#2HasFootnotes}} + {\global\togglefalse{@PB#2HasFootnotes}} + + \iftoggle{@PB#1HasMarginpars} + {\global\toggletrue{@PB#2HasMarginpars}} + {\global\togglefalse{@PB#2HasMarginpars}} + + \csdimgdef{@PB#2Height}{\csuse{@PB#1Height}} + \csdimgdef{@PB#2LeftHeight}{\csuse{@PB#1LeftHeight}} + \csdimgdef{@PB#2LeftFloatsHeight}{\csuse{@PB#1LeftFloatsHeight}} + \csdimgdef{@PB#2RightHeight}{\csuse{@PB#1RightHeight}} + \csdimgdef{@PB#2RightFloatsHeight}{\csuse{@PB#1RightFloatsHeight}} + \csdimgdef{@PB#2UsedLeft}{\csuse{@PB#1UsedLeft}} + \csdimgdef{@PB#2UsedRight}{\csuse{@PB#1UsedRight}} + + \seq_gclear_new:c {@PB#2LeftFloatHeights} + \seq_gclear_new:c {@PB#2LeftFloatSpacesBelow} + \seq_gset_eq:cc {@PB#2LeftFloatHeights} {@PB#1LeftFloatHeights} + \seq_gset_eq:cc {@PB#2LeftFloatSpacesBelow} {@PB#1LeftFloatSpacesBelow} +} +\ExplSyntaxOff + +\newcommand\@PBsavePageDataAs[2]{ + \@PBsaveDimAs{@PB#1Height}{@PB#2Height} + \@PBsaveDimAs{@PB#1LeftHeight}{@PB#2LeftHeight} + \@PBsaveDimAs{@PB#1LeftFloatsHeight}{@PB#2LeftFloatsHeight} + \@PBsaveDimAs{@PB#1RightHeight}{@PB#2RightHeight} + \@PBsaveDimAs{@PB#1RightFloatsHeight}{@PB#2RightFloatsHeight} + \@PBsaveDimAs{@PB#1UsedLeft}{@PB#2UsedLeft} + \@PBsaveDimAs{@PB#1UsedRight}{@PB#2UsedRight} + + \@PBsaveToggleAs{@PB#1HasFloats}{@PB#2HasFloats} + \@PBsaveToggleAs{@PB#1HasFloatcol}{@PB#2HasFloatcol} + \@PBsaveToggleAs{@PB#1HasFootnotes}{@PB#2HasFootnotes} + \@PBsaveToggleAs{@PB#1HasMarginpars}{@PB#2HasMarginpars} + + \@PBsaveSeqAs{@PB#1LeftFloatHeights}{@PB#2LeftFloatHeights} + \@PBsaveSeqAs{@PB#1LeftFloatSpacesBelow}{@PB#2LeftFloatSpacesBelow} +} + +\newcommand\@PBsavePageData[1]{ + \@PBsavePageDataAs{#1}{#1} +} + +\newcommand\@PBsaveToggleAs[2]{ + \immediate\write\@mainaux{\providetoggle{#2}} + \iftoggle{#1} + {\immediate\write\@mainaux{\global\toggletrue{#2}}} + {\immediate\write\@mainaux{\global\togglefalse{#2}}} +} + +\newcommand\@PBsaveToggle[1]{ + \@PBsaveToggleAs{#1}{#1} +} + +\newcommand\@PBsaveDimAs[2]{ + \immediate\write\@mainaux{\csdimgdef{#2}{\csuse{#1}}} +} + +\newcommand\@PBsaveDim[1]{ + \@PBsaveDimAs{#1}{#1} +} + +\ExplSyntaxOn +\newcommand\@PBsaveSeqAs[2]{ + \immediate\write\@mainaux{\string\ExplSyntaxOn} + \immediate\write\@mainaux{\string\seq_gclear_new:c {#2}} + \seq_map_inline:cn {#1} + {\immediate\write\@mainaux{\string\global\string\seq_put_right:cn {#2}{##1}}} + \immediate\write\@mainaux{\string\ExplSyntaxOff} +} +\ExplSyntaxOff + +\newcommand\@PBsaveSeq[1]{ + \@PBsaveSeqAs{#1}{#1} +} + +% \end{macrocode} +% \Finale diff --git a/macros/latex/contrib/pbalance/pbalance.ins b/macros/latex/contrib/pbalance/pbalance.ins new file mode 100644 index 0000000000..2e7d2a2db8 --- /dev/null +++ b/macros/latex/contrib/pbalance/pbalance.ins @@ -0,0 +1,49 @@ +%% Copyright 2020 Nelson Lago +%% +%% 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 +%% 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. +%% +%% This work has the LPPL maintenance status `maintained'. +%% +%% The Current Maintainer of this work is Nelson Lago . + +\input docstrip.tex +\keepsilent +\usedir{tex/latex/pbalance} + +\preamble +Copyright 2020 Nelson Lago + +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 +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. + +This work has the LPPL maintenance status `maintained'. + +The Current Maintainer of this work is Nelson Lago . + +\endpreamble + +\generate{\file{pbalance.sty}{\from{pbalance.dtx}{package}}} + +\obeyspaces +\Msg{****************************************************} +\Msg{* *} +\Msg{* To finish the installation you have to move the *} +\Msg{* following file into a directory searched by TeX: *} +\Msg{* *} +\Msg{* pbalance.sty *} +\Msg{* *} +\Msg{* To produce the documentation run the file *} +\Msg{* pbalance.dtx through LaTeX. *} +\Msg{* *} +\Msg{* Happy TeXing! *} +\Msg{* *} +\Msg{****************************************************} + +\endbatchfile diff --git a/macros/latex/contrib/pbalance/pbalance.pdf b/macros/latex/contrib/pbalance/pbalance.pdf new file mode 100644 index 0000000000..319570a8dd Binary files /dev/null and b/macros/latex/contrib/pbalance/pbalance.pdf differ -- cgit v1.2.3