needspace.sty

% needspace.sty
%
% Provides commands to reserve space at the bottom of a page. If there
% is not enough space on the current page (column) a new page (column)
% is started.
%
% Author: Peter Wilson, Herries Press
% Maintainer: Will Robertson (will dot robertson at latex-project dot org)
% Copyright 1996--2003 Peter Wilson
% Released under the LaTeX Project Public License
%
%
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{needspace}[2009/09/03 v1.3b reserve vertical space]

\newcommand{\needspace}[1]{\begingroup\setlength{\dimen@}{#1}%
  \vskip\z@\@plus\dimen@ \penalty -100\vskip\z@\@plus -\dimen@
  \vskip\dimen@ \penalty 9999\vskip -\dimen@\endgroup}

\newcommand{\Needspace}{\@ifstar{\@sneedsp@}{\@needsp@}}

\newcommand{\@sneedsp@}[1]{\par \penalty-100\begingroup
  \setlength{\dimen@}{#1}%
  \dimen@ii\pagegoal \advance\dimen@ii-\pagetotal
  \ifdim \dimen@>\dimen@ii
    \break
  \fi\endgroup}

\newcommand{\@needsp@}[1]{\par \penalty-100\begingroup
  \setlength{\dimen@}{#1}%
  \dimen@ii\pagegoal \advance\dimen@ii-\pagetotal
  \ifdim \dimen@>\dimen@ii
    \ifdim \dimen@ii>\z@
      \vfil
    \fi
    \break
  \fi\endgroup}

\endinput

%     Example uses:
%
% ... previous text.\par
% \needspace{5\baselineskip} % need next 5 lines on a single page/column
% The next five lines ...
%
% \Needspace*{4\baselineskip} % need 4 lines kept on same page
%    The major principles are:
% \begin{itemize}
% \item ...
% 
%
%     The \needspace macro reserves an APPROXIMATE amount of space (depending
% on what penalties are in effect) but is efficient and normally adequate.
% A short page will be ragged bottom even if \flushbottom is in
% effect.
%
%     \Needspace is less efficient but reserves the requested space. It
% should only be used between paragraphs. Short pages produced by 
% \Needspace{<length>} will be ragged bottom but short pages produced by 
% \Needspace*{<length>} will be flush bottom if \flushbottom is in effect.
%
% Changes v1.3b (2009/09/03)
%   New maintainer (Will Robertson)
%
% Changes v1.3a (2003/02/18)
%   At the suggestion of Donald Arseneau (private emails) changed guts of
%   \needspace from 
%   ... \vskip\z@\@plus\dimen@\pagebreak[3]\vskip\z@\@plus-\dimen@\endgroup}
%
% Changes v1.3 (2003/02/07)
%   Added \Needspace (an extended version of postings by Donald Arseneau 
%   to comp.text.tex e.g., in November 1993, August 1995, September 1997, ...)
%
% Changes v1.2 (2002/09/11)
%   At the suggestion of Robin Fairbairns, added use of \dimen@ to capture 
%   the argument so that calc package commands can be used in the argument.
%
% 
%