% S H A P E P A R . S T Y
%
% Typeset paragraphs in various shapes.
%
% Version 1.01  (March 1993)
%
% Copyright (c) 1993    Donald Arseneau
% These definitions may be freely transmitted, reproduced, or modified for
% non-commercial purposes provided that this notice is left intact.
%
% \shapepar: a macro to typeset paragraphs in a specific shape. The
% size is adjusted automatically so that the entire shape is filled
% with text. There can be no displayed math, and no "\vadjust"
% material (no "\vspace").  These macros work for both LaTeX and plain
% TeX.  For LaTeX, specify \documentstyle[...shapepar...], or for
% either, \input shapepar.sty .  Instructions for use are given after
% \endinput below.
%
%---------------------
% make file load whatever status of @
\expandafter\edef\csname SH@catcode\endcsname
  {\catcode`\noexpand\@=\the\catcode`\@
   \catcode`\noexpand\$=\the\catcode`\$
   \let \csname SH@catcode\endcsname \noexpand\UnDefinedButNoAt}
\catcode`\@=11  \catcode`\$=11

% Define variables.  Use LaTeX names for some.

\def\@empty{}
\ifx\@tempdima\@und@fined \csname newdimen\endcsname \@tempdima \fi
\ifx\@tempdimb\@und@fined \csname newdimen\endcsname \@tempdimb \fi
\ifx\@tempcnta\@und@fined \csname newcount\endcsname \@tempcnta \fi
\ifx\@tempcntb\@und@fined \csname newcount\endcsname \@tempcntb \fi
\ifx\@tempboxa\@und@fined \csname newbox\endcsname \@tempboxa \fi

% Most are defined as aliases for previously-allocated registers.
% In the future, the descriptive names may disappear altogether.

\def\@tempa#1#2#3{%  {"count"|"dimen"|"box"|"skip"}{\myname}{\realname}
  \ifx\@und@fined#3\csname new#1\endcsname#2% allocate new one
  \else\let#2#3\fi % alias is defined, so use it
 }

\@tempa{box}\SH@boxa\rootbox
\newbox\SH@boxb                   % global
\@tempa{dimen}\SH@pd\@savsk
\@tempa{count}\SH@ntries\@cla     % global
\@tempa{dimen}\spec@bot\p@renwd
\@tempa{dimen}\spec@top\jot
\@tempa{dimen}\spec@height\@wholewidth
\@tempa{dimen}\spec@incr\@halfwidth
\@tempa{dimen}\spec@position\@picht
\@tempa{dimen}\spec@nextpos\@ovxx
\@tempa{dimen}\spec@prevpos\@ovyy
\@tempa{dimen}\spec@hcenter\@xdim
\@tempa{dimen}\SH@scale\@ydim
\@tempa{dimen}\SH@dscale\dimen@i   % global
\@tempa{dimen}\SH@tottext\@toproom % global
\@tempa{dimen}\SH@posseg\@ovro
\@tempa{dimen}\SH@widseg\@ovri
\@tempa{dimen}\SH@posold\@ovdx
\@tempa{dimen}\SH@widold\@ovdy
\@tempa{dimen}\SH@weight\@dashdim
\@tempa{count}\SH@npslines\interdisplaylinepenalty
\@tempa{count}\SH@nline\@savsf

% How many times will \shapepar try to get the size of the paragraph?
\chardef\SH@maxtries=9

\def\Shapepar{\let\SH@usebox\box \shapepar}
\let\SH@usebox\unvbox

\def\shapepar#1{% #1 = shape specification.  May be a macro.
 \begingroup
  \par \endgraf
  \edef\SH@restog{\global\SH@ntries\the\SH@ntries
   \global\SH@dscale\the\SH@dscale \global\SH@tottext\the\SH@tottext}
  \SH@pd\prevdepth
  \let\\\relax \edef\SH@spec{#1}%
  \hyphenpenalty10 \exhyphenpenalty10 % optimise
  \doublehyphendemerits10 \adjdemerits10
  \hfuzz\maxdimen
  \setbox\SH@boxa\vbox\bgroup % set whole text on one line
   \parindent\z@ \leftskip\z@skip % \rightskip set below
   \spaceskip .333333emplus.8emminus.15em % optimise stretch
   \parfillskip\z@ plus\@ne fil
   \begingroup
    \linepenalty\@m
    \def\\{\unskip\penalty-200 \hskip1em plus\@m\p@ \penalty-60 }%
    \let\par\SH@endpar \hsize\maxdimen \rightskip\spaceskip
    \pretolerance\m@ne \hyphenpenalty 9000 % make discretionaries
    \ifx\textwidth\@undefined\else \textwidth\hsize
      \linewidth\hsize \columnwidth\hsize \fi
    \def\vadjust{{\def\SH@dm{special vertical material}\the\everydisplay}}%
    \everydisplay{\errhelp{Press RETURN, and hope.}\errmessage
     {Shaped Paragraph Error: \SH@dm\space is illegal in a shaped paragraph}}%
    \noindent \penalty\@M \hskip\z@skip % allow hyphenation of first word
    \ignorespaces}

\def\SH@endpar{%
    \endgraf \endgroup % still inside \vbox and \begingroup
   \global\SH@dscale\z@
   \expandafter\SH@checkspec\SH@spec $% check height of spec.
%  get tottext = total length / 256 because total length may be > \maxdimen
   \setbox\@tempboxa\box\voidb@x \global\SH@tottext\z@
   \SH@sumlines % combine multiple lines -> \@tempboxa; width/256 ->\SH@tottext
%%%\message{total length = 256 * \the\SH@tottext; 
%%%\string\baselineskip=\the\baselineskip;
%%%and spec height = \pointless\spec@height. }%
   \unskip\unkern\unpenalty\unskip\unkern\unpenalty
   \setbox\SH@boxa\box\@tempboxa % all the text
   \@tempdima1.4\SH@tottext % optimise
   \@tempdima\pointless\@tempdima\baselineskip
   \sqrtcount\@tempdima  \sqrtofcount
   \multiply\sqrtcount 4096 % * sqrt(256) * 256
%  scale_guess = sqrt(2 * 256*[text_length/256] * baselineskip) / spec_ht
   \SH@scale\sqrtcount sp \fpdivide\SH@scale\spec@height
   \global\SH@ntries\z@ % real initialization
   \lineskiplimit-99\p@ \linepenalty\thr@@
   \ifx\emergencystretch\@undefined \tolerance9999 %\@M  % TeX 2
   \else \tolerance600 \emergencystretch 2em\relax % TeX 3
   \fi \pretolerance\m@ne \hbadness\@MM % avoid error messages
   \rightskip\z@ plus.1emminus.2em % optimise stretch/shrink
   \SH@tryparshape}

% \tryparshape: try a parshape with scale factor \SH@scale for \SH@spec
% For a given scale, it would take x lines of text to cover the shape,
% but only an integer number of lines (counted by \SH@nline) will be
% used.  The excess is evenly distributed at the top and bottom to preserve
% the symmetry of shapes.  The starting point is thus:
%
% spec_top + 1/2 * { spec_height - floor[ (spec_height-delta)/incr ]*incr }
%
\def\SH@tryparshape{%
  \advance\SH@scale\SH@dscale % shift scale factor by delta
  \message{(\the\SH@ntries) Try shape with scale \pointless\SH@scale\space
    (Delta = \pointless\SH@dscale).}%% <--more \message
  \def\SH@parshape{}\def\SH@lines{}\let\@elt\relax \SH@npslines\z@
  \spec@incr\baselineskip \fpdivide\spec@incr\SH@scale
  \spec@position\spec@height \advance\spec@position-.4\spec@incr % height-delta
  \SH@nline\spec@position \divide\SH@nline\spec@incr % number of lines
  \spec@position-\SH@nline\spec@incr % - height of n lines
  \advance\spec@position\spec@height % difference from desired height
  \divide\spec@position\tw@ % half the excess
  \advance\spec@position\spec@top % starting position
  \advance\spec@position-\spec@incr % pre-decrement
  \SH@nline\z@ % initialize counter for lines
%%\message{Parsing spec.}%
  \expandafter \SH@doaline \SH@spec \\$}
% this macro ends instead of continuing with \SH@done so TeX will use
% tail-recursion as \SH@tryparshape is iterated.
  
\def\SH@doaline{\SH@updps \SH@widold-\maxdimen
  \advance\SH@nline\@ne \advance\spec@position\spec@incr
  \ifdim\spec@position<\spec@bot
    \let\\\SH@findpos
  \else
    \let\\\SH@dopara
  \fi \\}

\def\SH@findpos#1#2\\{\ifdim#1\p@>\spec@position
     \def\SH@nextspec{#2{}}\spec@nextpos#1\p@ \def\\{\SH@found{#1}#2\\}%
     \expandafter\def\expandafter\SH@prevspec\expandafter{\SH@Prevspec}%
  \else
     \def\SH@Prevspec{#2{}}\spec@prevpos#1\p@
  \fi \\}

\def\SH@found{% calculate weights to interpolate
  \SH@weight\spec@position \advance\SH@weight-\spec@prevpos
  \@tempdimb\spec@nextpos  \advance\@tempdimb-\spec@prevpos
  \fpdivide\SH@weight\@tempdimb % weight = interpolation factor
  \let\next \SH@dosegment  \SH@dosegment}

% Get the position and width of a segment of text by taking the weighted
% average of the specifications from above and below (weighted by nearness).
% Most of the confusing bits here are hueristics to deal with narrow gaps.
% If a gap between two texts is less than a space, the texts are joined
% over the gap.  If the gap is less than 1em, the gap is increased to the
% average of 1em and the given gap.

\def\SH@dosegment{% do a segment of text on this line
  \SH@posseg\z@ \SH@widseg\z@
  \advance\SH@weight-\p@ \SH@weight-\SH@weight % w1 = 1 - w2
  \SH@getseg A\SH@prevspec % Above
  \advance\SH@weight-\p@ \SH@weight-\SH@weight % w2 = 1 - w1
  \SH@getseg B\SH@nextspec % Below
  \ifdim\SH@widseg>\z@
     \SH@widseg\pointless\SH@scale\SH@widseg
     \advance\SH@posseg-\spec@hcenter
     \SH@posseg\pointless\SH@scale\SH@posseg
     \advance\SH@posseg.5\hsize
%    Here are the small-gap heuristics.  \@tempdima is the gap and the shift
     \ifdim\SH@widold>\z@
        \@tempdima\SH@posseg
        \advance\@tempdima-\SH@posold \advance\@tempdima-\SH@widold %gap
        \ifdim\@tempdima<\spaceskip % gap too small; eliminate
%%%%       \message{Gap is \the\@tempdima--eliminate. }%
           \advance\SH@widold\@tempdimb \advance\SH@widold\SH@widseg % no update
        \else
           \ifdim\@tempdima<1em % gap small; enlarge it if text not too small
              \ifdim\SH@widold>1em \ifdim\SH@widseg>1em
%%%%                \message{Gap is \the\@tempdima--enlarge}%
                    \@tempdima-.25\@tempdima \advance\@tempdima.25em
%%%%                \message{by 2 x \the\@tempdima. }%
                    \advance\SH@widold-\@tempdima
                    \advance\SH@widseg-\@tempdima
                    \advance\SH@posseg \@tempdima
           \fi\fi\fi
           \SH@updps
        \fi
     \else % no previous, so no update.  Just hold.
        \SH@widold\SH@widseg \SH@posold\SH@posseg
  \fi\fi
  \ifx\SH@prevspec\@empty \let\next\SH@doaline \fi
  \ifx\SH@nextspec\@empty \let\next\SH@doaline \fi
  \next}

\def\SH@updps{% Update parshape with `new' info
\ifdim\SH@widold>\z@
%%\message{.}%
  \edef\SH@parshape{\SH@parshape\the\SH@posold\the\SH@widold\space}%
  \edef\SH@lines{\@elt{\the\SH@nline}{\the\SH@posold}{\the\SH@widold}\SH@lines}%
  \advance\SH@npslines\@ne
\fi \SH@widold\SH@widseg \SH@posold\SH@posseg}
   
\def\SH@getseg#1#2{% A/B, spec
  \ifx#2\@empty \SH@specerror \fi
  \expandafter \SH@GetseG #2$#1#2}

\def\SH@GetseG#1#2$#3#4{% command, rest of spec, $, A/B, spec
   \expandafter \ifx\csname spec#3$#1\endcsname \relax 
     \SH@specerror
   \else
     \csname spec#3$#1\endcsname #2$#4%
   \fi}

\def\SH@redefine#1$#2{\def#2{#1}}

\def\SH@dopara#1\\${% eat remaining spec and test parshape
\global\setbox\SH@boxb\vbox{%
  \advance\SH@npslines\@ne
  \parshape\the\SH@npslines\space \SH@parshape \z@ \maxdimen
  \advance\SH@npslines\m@ne
%%\message{Formatting. }%
  \noindent \unhcopy\SH@boxa \endgraf
  \message{Expected \the\SH@npslines\space lines;
    got \the\prevgraf\space lines}% <--more \message
  \ifnum\prevgraf=\SH@npslines % maybe right size; check last line
     \ifdim\SH@widseg>\z@ % yes, we can check
        \ifnum\SH@ntries<\SH@maxtries % safe to screw around with \SH@npslines
           \SH@grablast \@tempdima\wd\SH@boxa \advance\@tempdima 20\p@
           \ifdim\@tempdima<.8\SH@widseg % final line underfull % optimise
              \message{but the last line is too empty. }%
              \advance\SH@npslines\@ne % flag underfullness
  \fi\fi\fi\fi
  \ifnum\prevgraf=\SH@npslines % right size, done
     \aftergroup\SH@done \global\SH@dscale\z@
  \else % Try a new scale factor
     \ifdim\SH@dscale=\z@ % no previous step.  Try to guess a good one
        \ifnum\prevgraf<\SH@npslines % underfull
%%%        \message{First underfull. }%
           \@tempdima\prevgraf\p@ 
           \divide\@tempdima\SH@npslines
        \else % overfull
%%%        \message{First overfull. }%
           \SH@grablast 
           \@tempdimb-\wd\SH@boxa \advance\@tempdimb-20\p@
           \divide\@tempdimb\@cclvi
           \@tempdima\SH@tottext \advance\@tempdimb\@tempdima
           \fpdivide\@tempdima\@tempdimb 
%%%      \message{overfullness: \the\wd\SH@boxa; ratio: \pointless\@tempdima}%
        \fi
        \sqrtcount\@tempdima \sqrtofcount \multiply\sqrtcount\@cclvi
        \@tempdima\sqrtcount sp
        \advance\@tempdima-\p@
        \global\SH@dscale\pointless\@tempdima\SH@scale
        \gdef\SH@fac{1}% % optimise
     \else % Not first step, scale from previous
        \ifnum\prevgraf>\SH@npslines % overflow now
           \ifdim\SH@dscale>\z@  % previous Overflow
              \global\SH@dscale \SH@fac\SH@dscale
           \else % overflow now, but previous underflow
              \gdef\SH@fac{.53}% % optimise
              \global\SH@dscale -\SH@fac\SH@dscale
           \fi
        \else  % underflow now
           \ifdim\SH@dscale>\z@  % previous Overflow
              \gdef\SH@fac{.54}% % optimise
              \global\SH@dscale -\SH@fac\SH@dscale
           \else % overflow now, but previous underflow
              \global\SH@dscale \SH@fac\SH@dscale
           \fi
        \fi 
     \fi
     \ifdim-\SH@dscale>.6\SH@scale
          \global\SH@dscale -.6\SH@scale  % avoid scale --> 0 !
     \fi
     \global\advance\SH@ntries\@ne
     \ifdim\AbsVal\SH@dscale <.005\p@ \global\SH@ntries\@cclv \fi
     \ifnum \SH@ntries>\SH@maxtries \aftergroup\SH@done
     \else \aftergroup\SH@tryparshape
  \fi\fi
}}% end \vbox,  end macro.  Must not insert anything between braces!

% Get last hbox off list; rebox it into \SH@boxa, omitting final glue
%
\def\SH@grablast{\unskip\unkern\unskip\unpenalty
  \setbox\SH@boxa\lastbox
  \ifhbox\SH@boxa
    \setbox\SH@boxa\hbox{\unhbox\SH@boxa\unskip\unskip\unpenalty}%
  \fi}


\def\SH@done{\skip@ 1spplus\p@ minus\p@
  \tolerance9999
  \rightskip\z@ plus.05emminus.1em % optimise, but should be same as above?
  \parfillskip.5\maxdimen % this will drag text to the bottom point.
  \advance\SH@npslines\@ne
  \SH@reform % reformat paragraph with new parfillskip
  \SH@nline\m@ne \let\@elt\SH@restack
  \message{Restacking.}%
  \global\setbox\SH@boxb\vbox{%  % re-stack segments and re-justify lines.
     \setbox\SH@boxa\vbox{}\leftskip\z@ plus55sp minus5\p@ % optimise
     \unvbox\SH@boxb
     \SH@lines \unvbox\SH@boxa}%
  \egroup % end original \setbox\SH@boxa\vbox\bgroup; but \SH@boxa is useless
 \SH@restog % restore global registers
 \SH@pd\dp\SH@boxb \SH@usebox\SH@boxb \prevdepth\SH@pd
 \endgroup % \prevdepth is global
\let\SH@usebox\unvbox % completely finished!
}

\def\SH@reform{\global\setbox\SH@boxb\vbox\bgroup
  \message{Reformat paragraph with \string\rightskip = \the\rightskip.}%
  \advance\parfillskip-\rightskip \advance\parfillskip-\leftskip
  \parshape\the\SH@npslines\space \SH@parshape \z@ .5\maxdimen
  %% get prevdepth from outside, penalty puts \parskip and favors breaks
  \prevdepth\SH@pd \ifdim\SH@pd>-\@m\p@ \penalty-50 \fi
  \noindent \unhcopy\SH@boxa \unskip\unskip\unpenalty\strut
  \penalty-\@M\hbox{\kern\hfuzz}\endgraf
  \ifnum\prevgraf=\SH@npslines % good, it worked.
    \setbox\SH@boxa\lastbox \unskip\unpenalty % remove mongo last box
    \egroup
  \else % something wrong, increase flexibility and try again
    \egroup %
    \ifnum\skip@<64 % try again
       \advance\rightskip\skip@
       \multiply\skip@\tw@
       \expandafter\expandafter\expandafter \SH@reform
  \fi\fi}

\def\SH@restack#1#2#3{% line num, shift, width
  \skip@\lastskip \unskip \advance\skip@\lastskip \unskip
  \@tempcnta\lastpenalty \unpenalty\unpenalty
  \setbox\@tempboxa\lastbox
%%\message{.}%
  \setbox\SH@boxa\vbox{%
     \ifhbox\@tempboxa
        \moveright#2\hbox to#3{\hskip\leftskip \unhbox\@tempboxa
        \unskip \hskip\leftskip}%
     \fi
     \ifnum\@tempcnta=\z@\else \penalty\@tempcnta \fi
     \vskip\skip@
     \ifnum\SH@nline=#1\relax \vskip-\baselineskip \fi
     \unvbox\SH@boxa}%
  \SH@nline#1\relax}

\def\SH@checkspec#1#2#3#4${% h-center, v-origin, "b", rest of spec
   \ifx b#3\else \SH@specerror \fi
   \spec@hcenter#1\p@ \spec@top#2\p@ \spec@bot-\maxdimen
   \def\SH@spec{{#2}b#4}%
   \let\\\SH@CheckSpec
   \\{#2}b#4\\{-1234.5}\\[$%
   \ifdim\spec@bot<-\@m\p@ \SH@specerror \fi
   \spec@height\spec@bot \advance\spec@height-\spec@top
}

\def\SH@CheckSpec#1#2\\{\ifdim#1\p@<-\@m\p@ % finished
     \def\\[${}%
  \else \ifdim#1\p@<\spec@bot \SH@specerror
           \spec@bot-\p@ \def\\##1[${}%eat rest
        \else \spec@bot#1\p@
  \fi   \fi \\}

% b{pos}         begin text at a point at horizontal position pos.
% e{pos}         end text at a point at horizontal position pos.
% t{pos}{len}    make a block of text at position pos with length len
% s              split text (begin whitespace)
% j              join two text blocks (end a gap)

% Behavior of specs above:
\def\specA$b#1{\specA$t{#1}{0}}%  b(pos) -> t(pos)(0)
\def\specA$e#1#2{\csname specA$#2\endcsname}%  e(pos) ignore
\def\specA$s#1{\csname specA$#1\endcsname}%  s ignore % should never happen
\def\specA$t#1{\advance\SH@posseg#1\SH@weight \@spec$t jt{#1}}

\def\specB$e#1{\specB$t{#1}{0}}
\def\specB$b#1#2{\csname specB$#2\endcsname}
\def\specB$j#1{\csname specB$#1\endcsname}
\def\specB$t#1{\advance\SH@posseg#1\SH@weight \@spec$t st{#1}}

\def\@spec$t#1#2#3#4#5{% j|s  t  pos  wid  next
      \if t#2\else \SH@specerror \fi
      \advance\SH@widseg#4\SH@weight
      \if#1#5\relax % next is s (below) or j (above): unite two t
        \let\@tempa\@spec$t \else \let\@tempa\SH@redefine \fi
      \@tempa #5}

% Grab all the hboxes in the preceding list, combine their contents in
% \@tempboxa (removing \rightskip, separating with space), and give 
% SH@tottext = total_width / 256 (note that the total width may be 
% greater than \maxdimen)
%
\def\SH@sumlines{\SH@grablast 
\ifhbox\SH@boxa
  \@tempdima\wd\SH@boxa \divide\@tempdima\@cclvi 
  \global\advance\SH@tottext\@tempdima
  \setbox\@tempboxa\hbox{%
     \ifvoid\@tempboxa\else \unhbox\@tempboxa\space \fi
     \unhbox\SH@boxa}%
  \expandafter\SH@sumlines
\fi}

\def\SH@specerror{\errhelp{It would be amazing if you can continue after
  this error.}\errmessage
  {Shaped Paragraph Error:  Error in specification.  Check carefully! }}%


% Take a square root of counter \sqrtcount using Newton's method.
% Assign a number to \sqrtcount, then do \sqrtofcount.
% To take sqrt of a dimen, do:
%       \sqrtcount=\thedimen \sqrtofcount
%       \multiply\sqrtcount by 256 \thedimen=\sqrtcount sp
% (\@tempcnta and \@tempcntb are used and modified.)
\newcount\sqrtcount
\def\sqrtofcount{\relax\ifnum\sqrtcount>\z@
  \@tempcnta\sqrtcount \sqrtcount\@ne
  \expandafter\squinitial\the\@tempcnta\relax\relax\relax
  \squiterate
\else
  \sqrtcount\@ne 
\fi}
\def\squinitial#1#2{\ifx#1\relax \else
    \ifx #2\relax \multiply\sqrtcount \thr@@ % 3 ~ sqrt(10)
    \else    \multiply\sqrtcount 10
    \fi   \expandafter \squinitial
  \fi}
\def\squiterate{\@tempcntb\@tempcnta \divide\@tempcntb\sqrtcount
%%%\message{sqrt(\the\@tempcnta) guess: \the\sqrtcount. }%
   \advance\sqrtcount\@tempcntb \divide\sqrtcount\tw@
   \advance \@tempcntb -\sqrtcount
   \ifnum \AbsVal\@tempcntb>\thr@@ % approximate, use 1 for exact
   \expandafter \squiterate \fi}% expandafter to avoid stack overflows

\newcount\FPD@hi \FPD@hi=67108863

% Approximate Fixed Point Division of two dimensions
% 3.14159/2.71828 = 1.15573
% Two parameters: Numerator and denominator.  The answer is returned
% in the numerator (which must be a register).  The denominator is
% unchanged, but it should also be a dimen register. (It may be given 
% as an explicit *integer* string, "123", which is treated as 0.001877
% = 123/65536.)   % \@tempcntb is used and altered.
% 
\def\fpdivide#1#2{\let\FPD@nume#1\@tempcntb#2\relax
  \FPD@scale\FPD@scale\FPD@scale\FPD@scale
  \divide#1\@tempcntb}

% Rescale numbers to preserve accuracy.  The number 16 is the level of
% uncertainty. Use a lower power of 2 for more accuracy (2 is most precise).
% But if you change it, you must change the repetions of \FPD@scale in
% \fpdivide above: magic_number^repetitions = 65536 (16^4 = 65536).
%
\def\FPD@scale{\ifnum\AbsVal\FPD@nume<\FPD@hi
    \multiply\FPD@nume\sixt@@n
  \else
    \divide\@tempcntb\sixt@@n
  \fi}

% take absolute value of TeX number or dimension
\def\AbsVal#1{\ifnum#1<\z@-\fi#1}

\def\pointless#1{\expandafter\remove@PT\the#1}
{\catcode`p=12 \catcode`t=12 \gdef\remove@PT#1pt{#1}}

\SH@catcode % restore catcodes

% If you have (computer) memory problems, the following shape
% definitions can be eliminated.

\def\diamondpar#1{\shapepar\diamondshape $\diamondsuit$ #1 $\diamondsuit$\par}
\def\diamondshape{{1}{0}b{1}\\{1}t{0}{2}\\{2}e{1}}

\def\squarepar#1{\shapepar{%
  {1}%            centerline at x=1
  {0}b{0}\\%      begin at (0,0)
  {0}t{0}{2}\\%   text at y=0, width=2
  {2}t{0}{2}\\%   text at y=2, width=2
  {2}e{1}%        end at (1,2)
}#1\par}

\def\heartpar#1{\shapepar{\heartshape}#1\unskip\unskip\penalty-300
\ \ $\heartsuit$\par}

\def\heartshape{%
{20}{0}b{13.32}b{26.68}%
\\{.14}t{10.12}{4.42}t{25.46}{4.42}%
\\{.7}t{9.14}{7.16}t{23.7}{7.16}%
\\{1.4}t{8.4}{9.02}t{22.58}{9.02}%
\\{2.1}t{7.82}{10.42}t{21.76}{10.42}%
\\{2.8}t{7.36}{11.58}t{21.06}{11.58}%
\\{3.5}t{6.98}{12.56}t{20.46}{12.56}%
\\{4.2}t{6.68}{13.32}jt{20}{13.32}%
\\{4.9}t{6.48}{27.04}%
\\{5.6}t{6.34}{27.32}%
\\{6.3}t{6.28}{27.44}%
\\{7}t{6.26}{27.48}%
\\{7.7}t{6.27}{27.46}%
\\{8.4}t{6.32}{27.36}%
\\{9.1}t{6.4}{27.2}%
\\{9.8}t{6.52}{26.96}%
\\{10.5}t{6.68}{26.64}%
\\{11.9}t{7.12}{25.76}%
\\{13.3}t{7.72}{24.56}%
\\{14.7}t{8.51}{22.98}%
\\{16.1}t{9.5}{21}%
\\{17.5}t{10.69}{18.62}%
\\{18.9}t{12.08}{15.84}%
\\{20.3}t{13.7}{12.6}%
\\{21.7}t{15.62}{8.76}%
\\{22.4}t{16.7}{6.6}%
\\{23.1}t{17.87}{4.26}%
\\{24.6}e{20}%
}

\def\nutshape{%
{0}%
{0}b{0}\\%
{0}t{-12.5}{25}\\%
{11.65}t{-19.23}{19.23}st{0}{19.23}\\%
{11.99}t{-19.42}{16.835}t{2.59}{16.835}\\%
{12.99}t{-20}{15}t{5}{15}\\%
{14.58}t{-20.92}{13.85}t{7.07}{13.85}\\%
{16.65}t{-22.11}{13.45}t{8.66}{13.45}\\%
{19.06}t{-23.51}{13.85}t{9.66}{13.85}\\%
{21.65}t{-25}{15}t{10}{15}\\%
{24.24}t{-23.51}{13.85}t{9.66}{13.85}\\%
{26.65}t{-22.11}{13.45}t{8.66}{13.45}\\%
{28.72}t{-20.92}{13.85}t{7.07}{13.85}\\%
{30.31}t{-20}{15}t{5}{15}\\%
{31.31}t{-19.42}{16.835}t{2.59}{16.835}\\%
{31.65}t{-19.23}{19.23}jt{0}{19.23}\\%
{43.3}t{-12.5}{25}\\%
{43.3}e{0}%
}
\endinput
%-------------------------------------------------------------------

       S H A P E P A R . S T Y    --   Instructions

\shapepar is a macro to typeset paragraphs of a specified shape.
The total size is adjusted automatically so that the entire shape is
filled with text.  This is distinct from the normal \parshape command
which specifies a shape *and* a size, which may be only partially
filled, or over-filled, from top to bottom.  In a \shapepar there
can be no displayed math, and no "\vadjust" material, (including
"\vspace"). \Shapepar (capital S) is just like \shapepar except the
paragraph is boxed so it cannot be split over two pages.  Shaping
paragraphs this way is a slow process, so this style is mainly
intended for cards, invitations etc., not for whole books!  Although
short paragraphs process much faster, only long paragraphs accurately
fill complex shapes.

These macros work for both LaTeX and plain TeX.  For LaTeX, specify
\documentstyle[...shapepar...], or for either, \input shapepar.sty.

The command \shapepar should be used at the beginning of a paragraph,
and it applies to the entire paragraph.  There is one parameter: a
description of the shape, <shape_spec>.

\shapepar {<shape_spec>} Text of the paragraph...

The <shape_spec> parameter is very complex, but there are a few
shapes predefined as macros in this file: \diamondshape, \heartshape
and \nutshape, which are used as examples in the instructions below.
There are also commands to use these shapes: \diamondpar, \squarepar
and \heartpar; for example, \heartpar begins \shapepar{\heartshape}#1
so you can use it like: 

\heartpar{This paragraph is too short to be recognized as a heart.}

The syntax rules for <shape_spec> are very specific, and must be
followed closely.  (In these rules, { } mean explicit braces, [ ]
denote optional parts, < > surround a keyword that is defined (perhaps
loosely), and | means "or"; do not type [ ] < > or |, but do type { }.)

<shape_spec> = {<h_center>} <lines>

<lines> = <line_spec> [\\<lines>]

That is, the shape is specified as a single number in braces, followed
by the specifications for the lines, with the lines separated by \\. The
final paragraph will have its <h_center> position centered on the page.
<h_center> is a number (like 10.5) of arbitrary units; whatever units
are used for lengths and positions in the <lines>, they just need to be
consistent. 

The lines in the spec are not lines of text; nor are they the lines
that you would use to draw the shape itself.  They are horizontal
scans across the shape at irregular intervals.  Curved shapes need
many scan lines for accurate rendering while simple shapes need only
a few.  To determine the line specifications, start by drawing the
shape on paper, then draw a series of horizontal lines across it,
including lines that just touch the top and the bottom of the figure.  
Each line crosses over pieces of the figure in some region.  These 
intersections of line and figure define a <line_spec>.

<line_spec> = {<v_pos>} <segment> [ other <segment>s ]

The <v_pos> is the vertical position of the line.  Each <line_spec> must
have a position greater than or equal to that of the previous line, and
with all <v_pos> > -1000. Position is measured from top to bottom, and
always moving down. Each <segment> represents a region where text will
go in the final paragraph; it is the segment of the horizontal scan line
that overlaps the body of the figure.  There are five types of segment:

<segment> = t{pos}{len} | b{pos} | e{pos} | s | j

  b{pos}         begin text at a point at horizontal position pos
  e{pos}         end text at a point at horizontal position pos
  t{pos}{len}    make a block of text at position pos with length len
  s              split text (begin whitespace)
  j              join two text blocks (end a gap)

The most common type of segment is t (text).  The other types are
degenerate in that they are single points rather than finite segments.
Types s and j have no explicit position, but they must appear between
text segments, and those texts should abut; e.g.,  t{3}{2}st{5}{4}
(text from 3 to 5 and text from 5 to 9).

Let's jump right into a simple example, and the meanings will be
clearer.  A "diamond" shape can have the four vertices:

                   (x=1,y=0)
                       .
  +---> x
  !          (0,1) .       . (2,1)
  !
  V y                  .
                     (1,2)


This shape can be exactly specified by just three scan lines passing
through the vertices.  The specification is:

{1}%            h_center: x = 1
{0}b{1}\\%      text block begins at point y=0, x=1
{1}t{0}{2}\\%   this scan (at y=1) crosses text (len=2) starting at x=0
{2}e{1}         text block ends at point y=2, x=1

Other specification lines, like

{1.5}t{0.5}{1}\\%

could be inserted, but would make no difference--the shape is
interpolated linearly between scan lines.

Every block of text must start with a b specifier and end with an e
spec on some line below.  Every segment specified by t must have a
length greater than zero. If two blocks of text merge to form one (like
at the notch of a heart shape) there should be a j spec at the point of
junction.  If one block bifurcates (like at the top of a hole in a
doughnut) there should be an s spec.

Thus, the first line for any valid shape description must consist
of only b segment descriptors; the last line can only have e type
descriptors.  Although the definition of the units is arbitrary, the
numbers should range in magnitude from ~.1 - 100 to avoid numeric 
overflows and underflows.

If there are errors in the format of the specification, \shapepar
might complain with the error message

 Shaped Paragraph Error:  Error in specification.  Check carefully!

At this point you may as well type x or e, as there is very little
chance that TeX will continue successfully.  You might also get one
of TeX's regular error messages, like

        Illegal unit of measure (pt inserted).
or
        Missing number, treated as zero.

or you might get no error message at all, just ridiculous formatting.
Check shape syntax carefully against the rules and the examples before
running them through TeX.

What to do if the figure does not start at a point--if it has a flat
top?  It can start at a single point, but have the next scan line at
the same vertical position!  A square paragraph is specified by:

  {1}%            centerline at x=1 (x=1 is horizontally centered on page)
  {0}b{0}\\%      begin at (0,0)
  {0}t{0}{2}\\%   text at y=0, width=2
  {2}t{0}{2}\\%   text at y=2, width=2
  {2}e{1}%        end at (1,2)

Both \diamondpar and \squarepar are defined above as paragraphs with
these shapes.

Now let's get more ambitious.  A heart shape must have two simultaneous
beginnings, a short stretch of separate text, ending with a join,
whereafter there is just one stretch of text leading to the final
bottom point.  This shape has many scan lines so that the smooth
flowing curves are preserved.

\def\heartshape{%
{20}{0}b{13.32}b{26.68}%
\\{.14}t{10.12}{4.42}t{25.46}{4.42}%
\\{.7}t{9.14}{7.16}t{23.7}{7.16}%
\\{1.4}t{8.4}{9.02}t{22.58}{9.02}%
\\{2.1}t{7.82}{10.42}t{21.76}{10.42}%
\\{2.8}t{7.36}{11.58}t{21.06}{11.58}%
\\{3.5}t{6.98}{12.56}t{20.46}{12.56}%
\\{4.2}t{6.68}{13.32}jt{20}{13.32}%
\\{4.9}t{6.48}{27.04}%
\\{5.6}t{6.34}{27.32}%
\\{6.3}t{6.28}{27.44}%
\\{7}t{6.26}{27.48}%
\\{7.7}t{6.27}{27.46}%
\\{8.4}t{6.32}{27.36}%
\\{9.1}t{6.4}{27.2}%
\\{9.8}t{6.52}{26.96}%
\\{10.5}t{6.68}{26.64}%
\\{11.9}t{7.12}{25.76}%
\\{13.3}t{7.72}{24.56}%
\\{14.7}t{8.51}{22.98}%
\\{16.1}t{9.5}{21}%
\\{17.5}t{10.69}{18.62}%
\\{18.9}t{12.08}{15.84}%
\\{20.3}t{13.7}{12.6}%
\\{21.7}t{15.62}{8.76}%
\\{22.4}t{16.7}{6.6}%
\\{23.1}t{17.87}{4.26}%
\\{24.6}e{20}%
}

Look at \heartshape and find the two b specifiers at the beginning; find
the j a few lines below. Notice that above the j there are two segments
per line, but only one below it; the text to the left and right of the
join meet at the join point: 20.  I drew this heart freehand, and  measured
lengths from the sketch, so you should be able to do better!

Text can have holes.  For example, a doughnut-shape would have a  b on
the first line, followed by some lines with a single t,  then a line with
t s t at the start of the hole. The hole is represented by lines with two
t specs--the gap between them is the hole.  A line with  t j t ends the
hole.  There are more lines with single t, and then an e line to end
with.  Our final example is a nut.  Not a doughnut, but a hex-nut (for a
machine screw) -- a regular hexagon with a circular hole in the center.
The hexagon is flat on top and bottom so the specification begins and
ends like the square shape. The circle is rendered as a 24-gon, beginning
with a split (s) of the surrounding text and ending with a join (j).  If
the spacing of the scan lines looks odd, it is because the hexagon alone
would need few scans, but the circle needs many; the points on the circle
are at 15 degree intervals.

\def\nutshape{%
{0}%
{0}b{0}\\%
{0}t{-12.5}{25}\\%
{11.65}t{-19.23}{19.23}st{0}{19.23}\\%
{11.99}t{-19.42}{16.835}t{2.59}{16.835}\\%
{12.99}t{-20}{15}t{5}{15}\\%
{14.58}t{-20.92}{13.85}t{7.07}{13.85}\\%
{16.65}t{-22.11}{13.45}t{8.66}{13.45}\\%
{19.06}t{-23.51}{13.85}t{9.66}{13.85}\\%
{21.65}t{-25}{15}t{10}{15}\\%
{24.24}t{-23.51}{13.85}t{9.66}{13.85}\\%
{26.65}t{-22.11}{13.45}t{8.66}{13.45}\\%
{28.72}t{-20.92}{13.85}t{7.07}{13.85}\\%
{30.31}t{-20}{15}t{5}{15}\\%
{31.31}t{-19.42}{16.835}t{2.59}{16.835}\\%
{31.65}t{-19.23}{19.23}jt{0}{19.23}\\%
{43.3}t{-12.5}{25}\\%
{43.3}e{0}%
}

\shapepar cheats a bit when the horizontal gap between two bits of text
is small (like down in the notch of \heartpar).  When the gap is less
than an interword space it is eliminated, and the texts are joined; when
it is somewhat larger it is expanded to give it more visibility.  If you
want to eliminate this behavior, move the following definitions up into
the main part of the file.

%---- cut ----

\def\SH@dosegment{% do a segment of text on this line
  \SH@posseg\z@ \SH@widseg\z@
  \advance\SH@weight-\p@ \SH@weight-\SH@weight % w1 = 1 - w2
  \SH@getseg A\SH@prevspec % Above
  \advance\SH@weight-\p@ \SH@weight-\SH@weight % w2 = 1 - w1
  \SH@getseg B\SH@nextspec % Below
  \ifdim\SH@widseg>\z@
     \SH@widseg\pointless\SH@scale\SH@widseg
     \advance\SH@posseg-\spec@hcenter
     \SH@posseg\pointless\SH@scale\SH@posseg
     \advance\SH@posseg.5\hsize
     \edef\SH@parshape{\SH@parshape\the\SH@posseg\the\SH@widseg\space}%
     \edef\SH@lines{\@elt{\the\SH@nline}{\the\SH@posseg}{\the\SH@widseg}\SH@lines}%
     \advance\SH@npslines\@ne
  \fi
  \ifx\SH@prevspec\@empty \let\next\SH@doaline \fi
  \ifx\SH@nextspec\@empty \let\next\SH@doaline \fi
  \next}

  \let\SH@updps\relax

%---- cut ----

Since the processing is slow, there are some messages to say how
things are going.  These can be eliminated to save space (Put a % at
the start of every \message line.)  Or you can get even more verbose
messages by *removing* the % that precedes many other \message commands.

There are also a number of parameters which can be changed to affect
the size-optimisation procedure. Search for the word "optimise"

%-----------------------------------------
Version 1.01 (March 1993)  Small changes from initial release.

%
%  Test integrity of file:
%  brackets: round, square, curly, angle:   () [] {} <>
%  backslash, slash, vertical, at, dollar, and: \ / | @ $ &
%  hat, grave, acute (apostrophe), quote, tilde:   ^ ` ' " ~
