% \iffalse
%%
%% File: tocenter.dtx Copyright (C) 2002--2004 by Alexander I. Rozhenko
%%
%<package>\NeedsTeXFormat{LaTeX2e}
%<package>\ProvidesPackage{tocenter}
%<package>         [2004/12/09 v1.1 Centering Page Layout (NCC)]
%
% \changes{v1.0}{2002/01/31}{This version was uploaded to CTAN}
% \changes{v1.1}{2004/12/09}{Documentation was prepared}
%
%<*driver>
\documentclass{ltxdoc}
\usepackage{tocenter}
\GetFileInfo{tocenter.sty}
\begin{document}
\title{The \textsf{tocenter} package\thanks{This file
        has version number \fileversion, last
        revised \filedate.}}
\author{Alexander I. Rozhenko\\rozhenko@oapmg.sscc.ru}
\date{\filedate}
\maketitle
\DocInput{tocenter.dtx}
\end{document}
%</driver>
% \fi
%
% The package provides commands
% customizing the layout parameters of a documents.
%
% \section{User Interface}
%
% \DescribeMacro{\ToCenter}
% The |\ToCenter|\oarg{hfm}\marg{text-width}\marg{text-height} command
% calculates margins in such a way to center the specified text area
% together with header/footer/marginals areas on a sheet of paper.
% The optional \meta{hfm} parameter specifies what additional areas take into
% account while centering. It is a combination of three letters |h| (headers),
% |f| (footers), and |m| (marginal notes). If this parameters is omitted,
% additional areas are ignored while calculations. For example,
% the following command
% \begin{quote}
% |\ToCenter[h]{\textwidth}{\textheight}|
% \end{quote}
% centers the text+header area on the page. The text height and wight
% are not changed here. This command is useful in books without marginal
% notes.
%
% \DescribeMacro{\FromMargins}
% The |\FromMargins|\oarg{hfm}\marg{left}\marg{right}\marg{top}\marg{bottom}
% command calculates the page layout parameters in the MS Word-like style.
% It sets page margins to the values specified in the last four
% parameters and calculates the width and
% height of the text area in such a way to satisfy the requirements.
% For example, the command
% \begin{quote}
% |\FromMargins[hf]{20mm}{10mm}{25mm}{15mm}|
% \end{quote}
% calculates the text area dimensions and margins in such a way to
% provide 20~mm distance from the left edge of the page, 10~mm
% distance from the right edge, 25~mm distance from the top edge, and
% 15~mm distance from the bottom edge in assumption that header and
% footer are in use.
%
% If twoside mode is turned on, the left and right margins specified
% in the |\FromMargins| command are considered for odd pages.
% For even pages, their values are swapped.
%
% If |m|-letter is specified in the optional parameter, the margins are
% determined depending on two-side and two-column switches. In two-column mode,
% marginal notes are posed on both sides of paper, but in one-column mode
% the marginal notes are posed on the outer side of a page in two-side mode
% and to the right of the text area in one-side mode. All these specifics
% is taken into account while calculations of text margins.
% The reverse margin mode is also supported.
%
% \DescribeMacro{\ToCenter*}
% \DescribeMacro{\FromMargins*}
% The star-forms of these commands
% \begin{quote}
% |\ToCenter*|\marg{text-width}\marg{text-height}\\
% |\FromMargins*|\marg{left}\marg{right}\marg{top}\marg{bottom}
% \end{quote}
% are intended for positioning of simple documents without headers,
% footers, marginal notes, cross-references, and table of contents.
% Additionally, the empty page style is set and the writing to aux-file
% is suppressed.
%
% \textit{All mentioned commands are allowed in the preamble only.}
% \StopEventually{}
%
% \section{The Implementation}
%
% \begin{macro}{\NCC@pos}
% The |\NCC@pos|\marg{hfm} command parses the \meta{hfm} parameter
% and prepares |\NCC@h|\marg{register}, |\NCC@f|\marg{register},
% and |\NCC@m|\marg{register} commands to adjust values of skip
% registers. The |\NCC@pos| command is also useful in the |cropmark| package.
%    \begin{macrocode}
%<*package>
\def\NCC@pos#1{%
  \let\NCC@h\@gobble \let\NCC@f\@gobble \let\NCC@m\@gobble
  \@tfor\@tempa:=#1\do{%
%    \end{macrocode}
% If |h|-letter appears, the |\NCC@h| hook will adjust the value of register
% on the header height and separation:
%    \begin{macrocode}
    \if h\@tempa
      \def\NCC@h##1{\advance##1\headsep \advance##1\headheight}%
     \else
%    \end{macrocode}
% If |f|-letter appears, the |\NCC@f| hook will adjust the value of register
% on the footer skip distance:
%    \begin{macrocode}
      \if f\@tempa
        \def\NCC@f##1{\advance##1\footskip}%
       \else
%    \end{macrocode}
% If |m|-letter appears, the |\NCC@m| hook will adjust the value of register
% on the width and separation of marginal paragraphs:
%    \begin{macrocode}
        \if m\@tempa
          \def\NCC@m##1{\advance##1\marginparwidth
            \advance##1\marginparsep}%
        \fi
      \fi
    \fi
  }%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\ToCenter}
% The star-form of this command differs in the omitted
% optional parameter, empty page style, and suppressed
% writing to external files:
%    \begin{macrocode}
\newcommand{\ToCenter}{%
  \@ifstar{\pagestyle{empty}\nofiles\NCC@center[]}{\NCC@center}%
}
\@onlypreamble\ToCenter
%    \end{macrocode}
% At the first, we parse the \meta{hfm} parameter:
%    \begin{macrocode}
\newcommand*{\NCC@center}[3][]{\NCC@pos{#1}%
%    \end{macrocode}
% Start calculations from horizontal margins and width:
% set text width and calculate in |\@tempdima| the
% whole width of area to be centered.
%    \begin{macrocode}
  \setlength\textwidth{#2}%
  \@tempdima\textwidth \NCC@m\@tempdima
%    \end{macrocode}
% In two-column mode, margins appear on both sides of text.
% We must add the width of marginal area again to |\@tempdima|:
%    \begin{macrocode}
  \if@twocolumn
    \NCC@m\@tempdima
%    \end{macrocode}
% In two-column mode, we set the odd and even side margins to
% \begin{quote}
% |\NCC@m{(\paperwidth-\@tempdima)/2}|:
% \end{quote}
%    \begin{macrocode}
    \@tempdimb\paperwidth
    \advance\@tempdimb -\@tempdima
    \@tempdima .5\@tempdimb \NCC@m\@tempdima
    \oddsidemargin\@tempdima
    \evensidemargin\@tempdima
%    \end{macrocode}
% In one-column mode with reverse margins, we set
% \begin{quote}
% |\evensidemargin:=(\paperwidth-\@tempdima)/2|\\
% |\oddsidemargin:=\NCC@m{(\paperwidth-\@tempdima)/2}|
% \end{quote}
% and, with normal margins, we set
% \begin{quote}
% |\oddsidemargin:=(\paperwidth-\@tempdima)/2|\\
% |\evensidemargin:=\NCC@m{(\paperwidth-\@tempdima)/2}|
% \end{quote}
%    \begin{macrocode}
  \else
    \@tempdimb\paperwidth
    \advance\@tempdimb -\@tempdima \@tempdima .5\@tempdimb
    \if@reversemargin
      \evensidemargin\@tempdima
      \NCC@m\@tempdima
      \oddsidemargin\@tempdima
    \else
      \oddsidemargin\@tempdima
      \NCC@m\@tempdima
      \evensidemargin\@tempdima
    \fi
  \fi
%    \end{macrocode}
% Now we calculate the vertical layout parameters.
% Again, in the |\@tempdima| we calculate the full
% height of useful areas and set the top margin to
% \begin{quote}
% |(\paperwidth-\@tempdima)/2|
% \end{quote}
% if headers are in use.
%    \begin{macrocode}
  \setlength\textheight{#3}%
  \@tempdima\textheight \NCC@h\@tempdima \NCC@f\@tempdima
  \@tempdimb\paperheight
  \advance\@tempdimb -\@tempdima
  \topmargin .5\@tempdimb
%    \end{macrocode}
% Otherwise, we decrease the value of top margin on the height
% and separation of header:
%    \begin{macrocode}
  \ifx\NCC@h\@gobble
    \advance\topmargin -\headsep
    \advance\topmargin -\headheight
  \fi
%    \end{macrocode}
% Do final correction of all margins: decrease their values
% on 1~inch. This compensates the default adjustment applied by
% dvi drivers.
%    \begin{macrocode}
  \advance \oddsidemargin  -1in
  \advance \evensidemargin -1in
  \advance \topmargin      -1in
}
\@onlypreamble\NCC@center
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\FromMargins}
% Finally, we implement the |\FromMargins| command.
%    \begin{macrocode}
\newcommand{\FromMargins}{%
  \@ifstar{\pagestyle{empty}\nofiles\NCC@margin[]}{\NCC@margin}%
}
\@onlypreamble\FromMargins
%    \end{macrocode}
% Again, start from parsing the \meta{hfm} parameter:
%    \begin{macrocode}
\newcommand*{\NCC@margin}[5][]{\NCC@pos{#1}%
%    \end{macrocode}
% Calculate horizontal parameters at first.
% In two-side mode, the left margin is equal to the
% |\oddsidemargin| and the right margin is equal to the
% |\evensidemargin|. In one-side mode, the
% |\oddsidemargin| is calculated in the same manner
% and the |\evensidemargin| is useless. So, we need
% not distinguish one-side and two-side modes here
% and do all things as for two-side mode.
%    \begin{macrocode}
  \setlength\oddsidemargin{#2}%
  \setlength\evensidemargin{#3}%
%    \end{macrocode}
% Calculate in |\@tempdima| the amount of space occupied
% by horizontal margins and marginal notes.
%    \begin{macrocode}
  \@tempdima\oddsidemargin \advance\@tempdima\evensidemargin
  \NCC@m\@tempdima
%    \end{macrocode}
% In two-column mode, marginal notes should be counted twice
% and the values of odd and even margins must be adjusted
% on the marginal width.
%    \begin{macrocode}
  \if@twocolumn
    \NCC@m\@tempdima
    \textwidth\paperwidth
    \advance\textwidth -\@tempdima
    \NCC@m\oddsidemargin \NCC@m\evensidemargin
%    \end{macrocode}
% In one-column mode, we must adjust only one margin
% depending on placement of marginal notes.
%    \begin{macrocode}
  \else
    \textwidth\paperwidth
    \advance\textwidth -\@tempdima
    \if@reversemargin
      \NCC@m\oddsidemargin
    \else
      \NCC@m\evensidemargin
    \fi
  \fi
%    \end{macrocode}
% Now we calculate the vertical layout parameters.
% We set the |\@tempdima| to the sum of
% top margin, bottom margin, header, and footer.
%    \begin{macrocode}
  \setlength\topmargin{#4}%
  \setlength\@tempdima{#5}\advance\@tempdima\topmargin
  \NCC@h\@tempdima \NCC@f\@tempdima
%    \end{macrocode}
% The rest of page is the text height:
%    \begin{macrocode}
  \textheight\paperheight
  \advance\textheight -\@tempdima
%    \end{macrocode}
% We must decrease the |\topmargin| on the header separation
% and height if headers are useless.
%    \begin{macrocode}
  \ifx\NCC@h\@gobble
    \advance\topmargin -\headsep
    \advance\topmargin -\headheight
  \fi
%    \end{macrocode}
% Do final correction of all margins:
%    \begin{macrocode}
  \advance \oddsidemargin  -1in
  \advance \evensidemargin -1in
  \advance \topmargin      -1in
}
\@onlypreamble\NCC@margin
%</package>
%    \end{macrocode}
% \end{macro}
\endinput
