%    tracking.sty
%
%    17 Mar 1996
%    Glazkov D.A.
%    e-mail: glazkov@sci.lpi.msk.su
%
%    117924 Moscow, Leninsky Prosp. 53
%    P.N.Lebedev Physical Institute of
%    Russian Academy of Sciences
%             RUSSIA
%
%       This style invoke the commands for tracking, i.e. automatical adjust
%       spaces between symbols in a words or phrases to fit them into needed
%       length. Any chain of symbols (including spaces) in current font may 
%       be treated. No commands, including font switching, are allowed in the
%       arguments of following macros - the result will be unpredictable.
%
%       The additional spaces between words are not disappear. It's meant that
%       the result of macros is placed onto one line of text, because it
%       is inserted into \hbox{...}.
%
%       These commands are based on the idea of the loop "\dolist" - see
%       D.Knuth "The TeXbook" (the answer for Ex. 11.5).
%
%
%       You may change this code freely. But please inform me if you use
%       or improve these commands.
%
%
%
%       Available commands:
%
%
%	\track{x}{abc}
%	    abc - initial chain of symbols
%           x   - additional space which is added to the right of each
%                 symbol but the last (including "spaces"). May be positive,
%                 negative and zero.
%                   Ex.  \track{-.3pt}{This is a probe}
%
%
%	\fittrack{x}{abc}
%           abc - initial chain of symbols
%           x   - final length for the result of this command. May be less
%                 or greater thah the length of the initial chain.
%                    Ex. \fittrack{8cm}{This is a probe}
%
%
%	\ratiotrack{x}{abc}
%           abc - initial chain of symbols
%           x   - ratio, showing how many times the result of this command
%                 is longer than the length of the initial chain. May be
%                 less, greater or equal to 1.
%                    Ex. \ratiotrack{1.2}{This is a probe}


\def\dolist{\afterassignment\dodolist\let\next= }
\def\dodolist{\ifx\next\endlist \let\next\relax
   \else \\\let\next\dolist \fi
   \next}
\def\endlist{\endlist}

\def\track#1#2{%
\def\\{\expandafter\if\space\next\setbox0=\hbox{\ }%
  \else \setbox0=\hbox{\next}\fi%
     \box0\kern#1}%
\leavevmode\hbox{\dolist#2\endlist\unkern}}

\def\fittrack#1#2{%
\newcount\n\n=0%
\def\\{\advance\n by1}%
\dolist#2\endlist%
\advance\n by-1%
\setbox0=\hbox{#2}%
\dimen0=#1\advance\dimen0 by-\wd0\divide\dimen0 by\n%
\track{\dimen0}{#2}}

\def\ratiotrack#1#2{%
\setbox0=\hbox{#2}\dimen0=#1\wd0\fittrack{\dimen0}{#2}}