%% $Id: xycmtip.doc,v 2.12 1994/10/25 11:34:25 kris Exp $
%%
%% XY-pic ``Computer Modern tips'' option.
%% Copyright (c) 1992-1994  Kristoffer H. Rose  <kris@diku.dk>
%%
%% This file is part of the XY-pic package for graphs and diagrams in TeX.
%% Copyright (c) 1991-1994  Kristoffer H. Rose  <kris@diku.dk>
%%
%% The XY-pic package is free software; you can redistribute it and/or modify
%% it under the terms of the GNU General Public License as published by the
%% Free Software Foundation; either version 2 of the License, or (at your
%% option) any later version.
%%
%% The XY-pic package is distributed in the hope that it will be useful, but
%% WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
%% or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
%% for more details.
%%
%% You should have received a copy of the GNU General Public License along
%% with this package; if not, write to the Free Software Foundation, Inc.,
%% 675 Mass Ave, Cambridge, MA 02139, USA.
%%
\ifx\xyloaded\undefined \input xy \fi

\xyprovide{cmtip}{Computer Modern tip extension}{\stripRCS$Revision: 2.12 $}%
 {Kristoffer H.~Rose}{kris@diku.dk}%
 {Computer Science, University of Copenhagen, Universitetsparken~1,
  DK--2100 K{\o}benhavn~{\O}}

\DOCMODE3%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

	This option provides arrow heads in the style of the Computer Modern
	fonts by Knuth~(see \cite{K86:ComputerMT} and
	\cite[appendix~F]{K84:TeXbook}).  These are often more pleasing in
	connection with curved arrows.

\DOCMODE2%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\paragraph*{Header:}\leavevmode
\DOCHEADER

\subsection{Fonts}

	First we load the fonts.

\DOCMODE(
\xyfont@\xycmatfont=xycmat10
\xyfont@\xycmbtfont=xycmbt10
\DOCMODE)

	Next we save the \XY-commands that may need restoring.

\DOCMODE(
\xylet@\xytip@=\tip@
\xylet@\xyatip@=\atip@
\xylet@\xybtip@=\btip@

\xylet@\xytipjot@=\tipjot@
\DOCMODE)

\subsection{Switching}

	Finally commands to switch the |cm| fonts on; they also set the
	|\jot| dimension temporarily to fit the smaller tips:

\DOCMODE(
\xydef@\xycm@{\let\xyatipfont=\xycmatfont \let\xybtipfont=\xycmbtfont}

\xydef@\cmtip@{\xycm@ \tip@x\tip@@}
\xydef@\cmatip@{\xycm@ \tip@x\atip@@}
\xydef@\cmbtip@{\xycm@ \tip@x\btip@@}
\DOCMODE)

\DOCMODE3%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{figure*}[t]
 %
 \UseComputerModernTips
 %
 \def\Dx#1#2{\hbox{\def\1{#1{#2}}\enspace\tt\string\dir\codeof\1}}
 %
 \def\DT#1#{\DTx{#1}}
 \def\DTx#1#2{\Dx{#1}{#2} & \vcenter{\xy
   -(4,2.5)*{} ; (4,0)*{} **{} ?>*\dir#1{#2} **\dir#1{.}
  \endxy}}
 %
 \def\Darray#1#2{{\let\\=\cr \tabskip=0pt plus 1fil %
  \halign to\hsize{&\hfil$##$&$##$\hfil\\
  \noalign{\hbox to\hsize{\hss#1\hss}\smallskip}#2\crcr}\bigskip}}
%
\Darray{Plain Computer Modern tips}{%
 \DT{>}	 &\DT^{>} &\DT_{>} \\
 \DT{<}	 &\DT^{<} &\DT_{<} \\
}
\bigskip
\Darray{Constructed Computer Modern tips}{%
 \DT{>>} &\DT^{>>} &\DT_{>>} \\
 \DT{<<} &\DT^{<<} &\DT_{<<} \\
 \DT{>|} &\DT{>>|} &\DT{|<}  \\
}
\caption{Computer Modern \protect<dir>ectionals}
??=[f.cmdir]
\end{figure*}

	The user can switch the ``computer modern'' versions of the
	directionals shown in figure~??[f.cmdir] on and off with these
	declarations: 
%
\begin{defs1}
 |\UseComputerModernTips| \cr
 |\NoComputerModernTips| \cr
\end{defs1}
\noindent\unskip
%
	They are local and thus can be switched on and/or off for individual
	pictures using the \TeX\ grouping mechanism, \eg,
%
\begin{code}
\xy*{} \ar
 @{*{\UseComputerModernTips\dir{<}}%
   -*{\NoComputerModernTips\dir{>}}}
 (20,5)*{} \endxy
\end{code}
\displaycode
\noindent
%
	will typeset
$$
\docode
$$
	regardless of the tip choice in the surrounding text.

\DOCMODE(
\xydef@\UseComputerModernTips{\def\tipjot@{.66\jot}%
 \let\tip@=\cmtip@ \let\atip@=\cmatip@ \let\btip@=\cmbtip@}

\xydef@\NoComputerModernTips{\let\tipjot@=\xytipjot@
 \let\tip@=\xytip@ \let\atip@=\xyatip@ \let\btip@=\xybtip@}
\DOCMODE)

\DOCMODE2%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\subsection{End \& log}

\DOCMODE(
\xyendinput

% $Log: xycmtip.doc,v $
% Revision 2.12  1994/10/25  11:34:25  kris
% Interim release just before v3 [works with AMS-LaTeX 1.2]...
%
% Revision 2.6  1993/10/21  20:36:09  kris
% NEW file to go in version 2.7!
%
% Extracted from xypic.doc 2.6.1.1.
\DOCMODE)

\DOCMODE3%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Tell Emacs how we are formatted:
% Local Variables:
% mode:latex
% fill-prefix:"\t"
% fill-column:77
% paragraph-separate:"^[ \t\f]*$\\|^[^\t]\\|\\\\\\\\\\|\\$\\$\\|[^\n\\\\][%&]"
% paragraph-start:"^[ \t\f]*$\\|^[^\t]\\|\\\\\\\\\\|\\$\\$\\|[^\n\\\\][%&]"
% End: