%D \module
%D   [       file=meta-txt,
%D        version=2000.07.06,
%D          title=\METAPOST\ Graphics,
%D       subtitle=Text Tricks,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

%D In this library some handy text manipulations are
%D defined. Some can and will be improved as soon as the
%D \TEX||\METAPOST\ interface is stable. Some of the
%D solutions may look weird, which is entirely my fault,
%D since I implemented them in the process of getting grip
%D on this kind of manipulations. Undoubtly better
%D \METAPOST\ code is possible, but my way of learning
%D this kind of trickery happens to be by \quote {trial
%D and error} and \quote {look and feel} (as well as
%D identifying tricks in Hobby's code).

% textext ipv btex ... etex

% we need a proper prefix here

\unprotect

\definesystemvariable {sh}  % ShapedText .. todo: commandhandler

\startMPextensions
    loadmodule "text" ;
\stopMPextensions

%%%%%%%

% \def\newchar#1{\chardef#1=0 }

\ifdefined\MPtoks       \else \newtoks\MPtoks        \fi
\ifdefined\MPbox        \else \newbox \MPbox         \fi

\ifdefined\parwidth     \else \newdimen\parwidth     \fi
\ifdefined\parheight    \else \newdimen\parheight    \fi
\ifdefined\parvoffset   \else \newdimen\parvoffset   \fi
\ifdefined\parhoffset   \else \newdimen\parhoffset   \fi
\ifdefined\parlines     \else \newcount\parlines     \fi
\ifdefined\partoks      \else \newtoks \partoks      \fi
\ifdefined\shapetextbox \else \newbox  \shapetextbox \fi
                              \newif   \ifparseries
\ifdefined\parfirst     \else \chardef \parfirst=0   \fi

\unexpanded\def\startshapetext[#1]%
  {\global\newcounter\currentshapetext
   \global\setbox\shapetextbox\vbox\bgroup
     \expanded{\switchtobodyfont[\@@shbodyfont]}%
     \dontcomplain
     \hsize\parwidth
     \setuptolerance[\v!verytolerant,\v!stretch]%
     \!!counta\zerocount
     \!!toksa\emptytoks
     \def\docommand##1%
       {\setbox\scratchbox\hbox{\useMPgraphic{##1}}%
        \global\chardef\parfirst\zerocount
        \getMPdata % \readlocfile{\MPdatafile}{}{}%
        \setshapecharacteristics
        \advance\!!counta by \parlines
        \expandafter\appendtoks\the\partoks\to\!!toksa}%
     \processcommalist[#1]\docommand
     \global\parseriestrue
     \xdef\totalparlines{\the\!!counta}%
     \global\partoks\!!toksa
    %\ifx\partoks\emptytoks\else % safeguard
       \expanded{\parshape \the\!!counta \the\!!toksa}%
    %\fi
     \setshapecharacteristics % extra dummy
     \ifparseries\def\par{\endgraf\adaptparshape}\fi
     \EveryPar{\begstrut}}

\unexpanded\def\stopshapetext
  {\endstrut
  %\removebottomthings
   \egroup
   \global\newcounter\currentshapetext
   \getshapecharacteristics}

\unexpanded\def\adaptparshape
  {\def\docommand##1%
     {\ifcase\!!counta
        \expandafter\appendtoks\space##1 \to\!!toksa
      \else
        \advance\!!counta \minusone
      \fi}%
   \!!counta\prevgraf
   \doglobal\decrement(\totalparlines,\!!counta)%
   \multiply\!!counta \plustwo
   \!!toksa\emptytoks
   \expanded{\processseparatedlist[\the\partoks][\space]}\docommand
   \global\partoks\!!toksa
  %\ifx\partoks\emptytoks\else % safeguard
     \expanded{\parshape\totalparlines\the\partoks}%
 }%\fi}

\unexpanded\def\getshapecharacteristics
  {\doglobal\increment\currentshapetext
   \doifelsedefined{parlines:\currentshapetext}
     {\global\parlines         \getvalue{parlines:\currentshapetext}%
      \global\chardef\parfirst \getvalue{parfirst:\currentshapetext}%
      \global\parvoffset       \getvalue{parvoffset:\currentshapetext}%
      \global\parhoffset       \getvalue{parhoffset:\currentshapetext}%
      \global\parwidth         \getvalue{parwidth:\currentshapetext}%
      \global\parheight        \getvalue{parheight:\currentshapetext}}
     {\global\parlines         \plusone
      \global\chardef\parfirst \zerocount
      \global\parvoffset       \zeropoint
      \global\parhoffset       \zeropoint
      \global\parwidth         \hsize
      \global\parheight        \vsize}}

\unexpanded\def\setshapecharacteristics
  {\doglobal\increment\currentshapetext
   \setxvalue{parlines:\currentshapetext  }{\the\parlines}%
   \setxvalue{parfirst:\currentshapetext  }{\the\parfirst}%
   \setxvalue{parvoffset:\currentshapetext}{\the\parvoffset}%
   \setxvalue{parhoffset:\currentshapetext}{\the\parhoffset}%
   \setxvalue{parwidth:\currentshapetext  }{\the\parwidth}%
   \setxvalue{parheight:\currentshapetext }{\the\parheight}}

\unexpanded\def\getshapetext % option: unvbox
  {\vbox\bgroup
   \forgetall
   \dontcomplain
   \setbox\scratchbox\vbox to \parheight
     {\expanded{\switchtobodyfont[\@@shbodyfont]}% evt strutheight en
      \splittopskip\strutheight               % lineheight opslaan
      \vskip\parvoffset                       % scheelt switch en
      \ifcase\parfirst\or\vskip\lineheight\fi % is ook veiliger
      \hskip\parhoffset
      \hbox{\vsplit\shapetextbox to \parlines\lineheight}}%
   \wd\scratchbox\parwidth
   \ht\scratchbox\parheight
   \dp\scratchbox\zeropoint
   \box\scratchbox
   \getshapecharacteristics
   \egroup}

\unexpanded\def\setupshapetexts
  {\dodoubleempty\getparameters[\??sh]}

\setupshapetexts
  [\c!bodyfont=]

\doifundefined{RotFont}{\definefont[RotFont][RegularBold*default]}

% \startuseMPgraphic{followtokens}
%   % we default to nothing
% \stopuseMPgraphic

% \unexpanded\def\processfollowingtoken#1% strut toegevoegd
%   {\appendtoks#1\to\MPtoks
%    \setbox\MPbox=\hbox{\RotFont\setstrut\strut\the\MPtoks}%
%    \startMPdrawing
%      n := n + 1 ; len[n] := \the\wd\MPbox ;
%    \stopMPdrawing
%    \startMPdrawing[-]
%    % pic[n] := textext{\RotFont\setstrut\strut#1} ; % btex \RotFont\setstrut\strut#1 etex ;
%      pic[n] := btex \RotFont\setstrut\strut#1 etex ;
%      pic[n] := pic[n] shifted - llcorner pic[n] ;
%    \stopMPdrawing}
%
% \unexpanded\def\dofollowtokens#1#2%
%   {\vbox\bgroup
%    \forgetall
%    \dontcomplain
%    \doifundefined{RotFont}{\definefont[RotFont][RegularBold*default]}%
%    \MPtoks\emptytoks
%    \resetMPdrawing
%    \startMPdrawing
%      \includeMPgraphic{followtokens} ;
%      picture pic[] ; numeric len[], n ; n := 0 ;
%    \stopMPdrawing
%    \handletokens#2\with\processfollowingtoken
%    \startMPdrawing
%      if unknown RotPath  : path    RotPath  ; RotPath  := origin ; fi ;
%      if unknown RotColor : color   RotColor ; RotColor := black  ; fi ;
%      if unknown TraceRot : boolean TraceRot ; TraceRot := false  ; fi ;
%      if unknown ExtraRot : numeric ExtraRot ; ExtraRot := 0      ; fi ;
%      numeric al, at, pl, pc, wid, pos ; pair ap, ad ;
%      al := arclength RotPath ;
%      if al=0 :
%        al := len[n] + ExtraRot ;
%        RotPath := origin -- (al,0) ;
%      fi ;
%      if al<len[n]:
%        RotPath := RotPath scaled ((len[n]+ExtraRot)/al) ;
%        al := arclength RotPath ;
%      fi ;
%      if \number#1 = 1 :
%        pl := (al-len[n])/(if n>1 : (n-1) else : 1 fi) ;
%        pc := 0 ;
%      else : % centered / MP
%        pl := 0 ;
%        pc := arclength RotPath/2 - len[n]/2 ;
%      fi ;
%      if TraceRot :
%        draw RotPath withpen pencircle scaled 1pt withcolor blue ;
%      fi ;
%      for i=1 upto n :
%        wid := abs(xpart urcorner pic[i] - xpart llcorner pic[i]) ;
%        pos := len[i]-wid/2 + (i-1)*pl + pc ;
%        at := arctime   pos of RotPath ;
%        ap := point     at  of RotPath ;
%        ad := direction at  of RotPath ;
%        draw pic[i] shifted (-wid/2,0) rotated(angle(ad)) shifted ap
%          withcolor RotColor ;
%        if TraceRot :
%          draw boundingbox
%             pic[i] shifted (-wid/2,0) rotated(angle(ad)) shifted ap
%             withpen pencircle scaled .25pt withcolor red ;
%          draw ap
%             withpen pencircle scaled .50pt withcolor green ;
%        fi ;
%      endfor ;
%    \stopMPdrawing
%    \MPdrawingdonetrue
%    \getMPdrawing
%    \resetMPdrawing
%    \egroup}

\unexpanded\def\getfollowtoken#1%
 {\hbox\bgroup
    \strut
    \ctxlua{mp.follow_text(#1)}%
  \egroup}

\definefontfeature[mp:tp][liga=no]

\startMPdefinitions
    def mfun_follow_draw (expr alternative) =
        if unknown RotPath  : path    RotPath  ; RotPath  := origin ; fi ;
      % if unknown RotColor : color   RotColor ; RotColor := black  ; fi ;
        if unknown TraceRot : boolean TraceRot ; TraceRot := false  ; fi ;
        if unknown ExtraRot : numeric ExtraRot ; ExtraRot := 0      ; fi ;
        picture pic[] ;
        numeric len[] ; len[0] := 0 ;
        numeric n ; n := lua.mp.follow_size() ;
        for i=1 upto n :
            pic[i] := lua.mp.follow_slot(i) ;
            pic[i] := pic[i] shifted - llcorner pic[i] ;
            len[i] := len[i-1] + lua.mp.follow_width(i) ;
        endfor ;
        numeric al, at, pl, pc, wid, pos ; pair ap, ad ;
        al := arclength RotPath ;
        if al = 0 :
            al := len[n] + ExtraRot ;
            RotPath := origin -- (al,0) ;
        fi ;
        if al < len[n]:
           RotPath := RotPath scaled ((len[n]+ExtraRot)/al) ;
           al := arclength RotPath ;
        fi ;
        if alternative = 1 :
           pl := (al-len[n])/(if n>1 : (n-1) else : 1 fi) ;
           pc := 0 ;
        else : % centered / MP
           pl := 0 ;
           pc := arclength RotPath/2 - len[n]/2 ;
        fi ;
        if TraceRot :
           draw RotPath withpen pencircle scaled 1pt withcolor blue ;
        fi ;
        for i=1 upto n :
          % wid := abs(xpart urcorner pic[i] - xpart llcorner pic[i]) ;
            wid := lua.mp.follow_width(i) ;
            pos := len[i]-wid/2 + (i-1)*pl + pc ;
            at := arctime   pos of RotPath ;
            ap := point     at  of RotPath ;
            ad := direction at  of RotPath ;
            if mfun_trial_run :
                % skip (ok, somewhat inefficient as we can consider a
                % dedicated store and textext variant (todo)
            else :
                pic[i] := pic[i] shifted (-wid/2,0) rotated(angle(ad)) shifted ap ;
                draw pic[i] ; % withcolor RotColor ;
                if TraceRot :
                    draw boundingbox pic[i] withpen pencircle scaled .25pt withcolor red ;
                    draw ap withpen pencircle scaled .50pt withcolor green ;
                fi ;
            fi ;
        endfor ;
        if TraceRot :
            draw boundingbox currentpicture withpen pencircle scaled .25pt withcolor blue ;
        fi ;
    enddef ;
\stopMPdefinitions

\startluacode
    local nodecodes = nodes.nodecodes

    local visible_code = {
        [nodecodes.glyph] = true,
        [nodecodes.glue]  = true,
        [nodecodes.hlist] = true,
        [nodecodes.vlist] = true,
        [nodecodes.rule]  = true,
    }

    local disc_code = nodecodes.disc
    local kern_code = nodecodes.kern

    local c_userkern = nodes.kerncodes.userkern
    local a_fontkern = attributes.private("fontkern")

    local n = nil
    local s = 0

    function mp.follow_reset()
        r = nil
        s = 0
    end

    function mp.follow_initialize(b)
        if not r then
            local l = tex.takebox(b).list
            n = { }
            s = 0
            while l do
                local c = l
                l = l.next
                local id = c.id
                if visible_code[id] then
                    s = s + 1
                    n[s] = c
                    c.prev = nil
                    c.next = nil
                elseif id == kern_code then
                    if c.subtype == c_userkern and not c[a_fontkern] then
                        s = s + 1
                        n[s] = c
                        c.prev = nil
                    else
                        n[s].next = c
                        c.prev = n[s]
                    end
                    c.next = nil
                elseif id == disc_code then
                    local r = c.replace
                    while r do
                        s = s + 1
                        n[s] = r
                        r = r.next
                        r.prev = nil
                        r.next = nil
                    end
                end
            end
        end
    end

    function mp.follow_size()
        mp.print(s)
    end

    function mp.follow_slot(i)
        mp.print('textext("\\getfollowtoken{' .. i .. '}")')
    end

    function mp.follow_text(s)
        context(n[s])
    end

    function mp.follow_width(i)
        mp.print(number.topoints(n[i].width))
    end
\stopluacode

\unexpanded\def\dofollowtokens#1#2%
  {\vbox\bgroup
   \forgetall
   \dontcomplain
   \setbox\scratchbox\hbox{\addff{mp:tp}#2}%
   \ctxlua{mp.follow_initialize(\number\scratchbox)}%
   \stopluacode
   \startMPcode
     \includeMPgraphic{followtokens} ;
     mfun_follow_draw(\number#1) ;
   \stopMPcode
   \ctxlua{mp.follow_reset()}%
   \egroup}

\unexpanded\def\followtokens        {\dofollowtokens1}
\unexpanded\def\followtokenscentered{\dofollowtokens0}

% stretched variant:
%
% \followtokens
%   {This is just a dummy text, kerned by T{\kern
%    -.1667em\lower .5ex\hbox {E}}{\kern -.125emX} and typeset
%    in a circle using {\setMFPfont M}{\setMFPfont
%    E}{\setMFPfont T}{\setMFPfont A}{\setMFPfont
%    P}{\setMFPfont O}{\setMFPfont S}{\setMFPfont T}.\quad}

% centered variant:
%
% \def\followtokengraphicscale#1{%%
%   \startuseMPgraphic {followtokens}
%     path RotPath; RotPath :=  reverse halfcircle scaled #1 ;
%     draw RotPath ;
%     setbounds currentpicture to boundingbox fullcircle scaled 12cm ;
%   \stopuseMPgraphic}
%
% \startoverlay
%   {\followtokengraphicscale{12cm}%%
%    \followtokenscentered{There was question on the list about this kind of graphics.}}
%   {\followtokengraphicscale{10cm}%%
%    \followtokenscentered{And Marco patched followingtokens to handle a centered text.}}
%   {\followtokengraphicscale{8cm}%%
%    \followtokenscentered{That ended up as variant branch in the main macro.}}
%   {\followtokengraphicscale{6cm}%%
%    \followtokenscentered{So now we have two commands.}}
% \stopoverlay

% \followtokengraphicscale{6cm}
% \followtokens{Hans Hagen uses {\darkred\TeX}, {\darkgreen\Lua}, {\darkblue \MetaPost} and friends.}

\startuseMPgraphic{fuzzycount}
   begingroup
   save height, span, drift, d, cp ;
   height := 3/ 5 * \baselinedistance ;
   span   := 1/ 3 * height ;
   drift  := 1/10 * height ;
   pickup pencircle scaled (1/12 * height) ;
   def d = (uniformdeviate drift) enddef ;
   for i := 1 upto \MPvar{n} :
     draw
       if (i mod 5)=0 : ((-d-4.5span,d)--(+d-0.5span,height-d))
       else           : ((-d,+d)--(+d,height-d)) fi
       shifted (span*i,d-drift) ;
   endfor;
   picture cp ; cp := currentpicture ; % for readability
   setbounds currentpicture to
     (llcorner cp shifted (0,-ypart llcorner cp) --
      lrcorner cp shifted (0,-ypart lrcorner cp) --
      urcorner cp -- ulcorner cp -- cycle) ;
   endgroup ;
\stopuseMPgraphic

\setupMPvariables
  [fuzzycount]
  [n=10]

\unexpanded\def\fuzzycount#1%
  {{\tx\useMPgraphic{fuzzycount}{n=#1}}}

\defineconversion[fuzzy][\fuzzycount]

%%%%%%%

\setupMPvariables
  [EnglishRule]
  [height=1ex,
   width=\the\localhsize, % without \the, problems in non e-tex
   color=darkgray]

\defineblank
  [EnglishRule]
  [medium]

\startuniqueMPgraphic{EnglishRule}{height,width,color}
    height = \MPvar{height} ;
    x1 = 0 ; x3 = \MPvar{width} ; x2 = x4 = .5x3 ;
    y1 = y3 = 0 ; y2 = -y4 = height/2 ;
    fill z1..z2..z3 & z3..z4..z1 & cycle withcolor \MPvar{color} ;
\stopuniqueMPgraphic

\unexpanded\def\EnglishRule
  {\startlinecorrection[EnglishRule]
   \setlocalhsize \noindent \reuseMPgraphic{EnglishRule}
   \stoplinecorrection}

%D The following macro returns a tight bound character
%D sequence.
%D
%D \useMPlibrary[txt]
%D
%D \startlinecorrection
%D \TightText{\ss\bf 123}{0cm}{3cm}{red}
%D \stoplinecorrection

\unexpanded\def\TightText#1#2#3#4%
  {\hbox % \ruledhbox
     {\startMPcode
        picture p ; p := image (graphictext "#1" withfillcolor red) ;
        draw p xsized #2 ysized #3 withcolor \MPcolor{#4} ;
      \stopMPcode}}

\protect \endinput