%
% ``Font Tricks'' borrowed from:
%  "The ABC's of Special Effects" by Georgia K.M. Tobin
%         TUGBoat 9 (1988) No 1 pp. 15--18
%  "Outline Fonts with Metafont" by Doug Henderson
%         TUGBoat 10 (1989) No 1 pp. 36--38.
%


\def\MFF@writetrick#1{\MFF@write{\space\space\space #1}}

% main trick subroutine (background + main char + shadow + transform)
%   z = empty (white), b = black,
%   v = vertical, h = horizontal, r = slanted(/), l - slanted (\)
%   d = dotted grig,   g = rectangular grid, s - slanted grid
%   uppercase(*) = (*) + outline
% transformations:
%   "z" - XY symmetry, "x" - symmetry OX, "y" - symmetry OY
%   "+" - rotate +90, "-" - rotate -90, "=" - rotate 180

\def\MFF@maketrick{%
    % initialization
    \if z\MFF@trickshadow\relax \else \MFF@shadowinit \fi
    \MFF@checktrick{\MFF@trickshadow}{vVhHrRlLdDgGsS}{\MFF@patterninit{SPen}}%
    \MFF@checktrick{\MFF@trickchar}{vVhHrRlLdDgGsS}{\MFF@patterninit{MPen}}%
    \MFF@checktrick{\MFF@trickbox}{ZvVhHrRlLdDgGsS}{\MFF@patterninit{HPen}}%
    \@negargtrue
    \MFF@checktrick{\MFF@trickchar}{ZBVHRLDGS}{}%
    \MFF@checktrick{\MFF@trickshadow}{ZBVHRLDGS}{}%
    \if@negarg\relax \else \MFF@outlineinit \fi
    % subroutine which repaces endchar
    \@negargtrue \if z\MFF@trickbox \@negargfalse \fi
    \MFF@trick@start{TrickChar}%
    \MFF@boxinit\MFF@trick@dochar{Normal}%
    \if z\MFF@trickshadow \else \MFF@trick@doshadow{Normal}{Shadow}\fi
    % make background
    \@negargtrue
    \MFF@checktrick{\MFF@trickbox}{zZ}{%
        \MFF@writetrick{clearit; picture BackChar; BackChar:=currentpicture;}%
    }%
    \if@negarg
        \if z\MFF@trickshadow
           \MFF@trick@helpdraw{Normal}{Back}{HPen}{\MFF@trickbox}%
        \else
           \MFF@trick@helpdraw{ShadowBox}{Back}{HPen}{\MFF@trickbox}%
        \fi
    \fi
    \MFF@checktrick{\MFF@trickbox}{ZBVHRLDGS}{%
        \MFF@writetrick{clearit; pickup HPen;}
        \MFF@writetrick{draw (rbXM,rbYM)--(rbXP,rbYM); draw (rbXP,rbYM)--(rbXP,rbYP);}
        \MFF@writetrick{draw (rbXP,rbYP)--(rbXM,rbYP); draw (rbXM,rbYP)--(rbXM,rbYM);}
        \MFF@writetrick{cullit; BackChar:=currentpicture + BackChar;}
    }%
    % make character
    \MFF@trick@trickhelp{\MFF@trickchar}{MPen}{Normal}{Main}%
    % make shadow
    \MFF@trick@trickhelp{\MFF@trickshadow}{SPen}{Shadow}{SMain}%
    % combine
    \MFF@writetrick{clearit; currentpicture:=BackChar+MainChar+SMainChar;}%
    \MFF@trick@end{TrickChar}%
    % correct char box
    % transformation
    \@negargfalse
    \@for\@temp:=\MFF@trick@transform\do
         {\csname MFF@help@transf@\@temp\endcsname}%
    % final box corrections
    \if z\MFF@trickbox \if@negarg \MFF@trick@makebox \fi
        \else \MFF@trick@shiftbox \@negargtrue \fi
    \if@negarg \MFF@trick@assignbox \fi
}

\def\MFF@help@transf@rr{\@negargtrue
    \MFF@trick@transf{FR}%
        {rotatedaround ((0,0),-90) shifted (0,tmpW)}%
        {tempI:=tmpW; tmpW:=tmpH; tmpH:=tempI+tmpP; tmpP:=tmpD; tmpD:=0;}%
        {tmptmp:=tmpwd; tmpwd:=tmpht; tmpht:=tmptmp+tmpwp; tmpwp:=tmpdp; tmpdp:=0pt\MFF@p;}%
}

\def\MFF@help@transf@rl{\@negargtrue
    \MFF@trick@transf{FL}%
        {rotatedaround ((0,0),+90) shifted (tmpH,0)}%
        {tempI:=tmpH; tmpH:=tmpW; tmpW:=tempI+tmpD; tmpD:=tmpP; tmpP:=0;}%
        {tmptmp:=tmpht; tmpht:=tmpwd; tmpwd:=tmptmp+tmpdp; tmpdp:=tmpwp; tmpwp:=0pt\MFF@p;}%
}

\def\MFF@help@transf@ro{\@negargtrue
    \MFF@trick@transf{FF}%
        {rotatedaround ((0,0),180) shifted (tmpW,tmpH)}%
        {tmpH:=tmpH+tmpD; tmpW:=tmpW+tmpP; tmpD:=0; tmpP:=0;}%
        {tmpht:=tmpht+tmpdp; tmpwd:=tmpwd+tmpwp; tmpdp:=0pt\MFF@p; tmpwp:=0pt\MFF@p;}%
}

\def\MFF@help@transf@sx{\@negargtrue
    \MFF@trick@transf{FY}%
        {reflectedabout ((0,0),(0,100)) shifted (tmpW,0)}%
        {tmpW:=tmpW+tmpP; tmpP:=0;}%
        {tmpwd:=tmpwd+tmpwp; tmpwp:=0pt\MFF@p;}%
}

\def\MFF@help@transf@sy{\@negargtrue
    \MFF@trick@transf{FX}%
        {reflectedabout ((0,0),(100,0)) shifted (0,tmpH)}%
        {tmpH:=tmpH+tmpD; tmpD:=0;}%
        {tmpht:=tmpht+tmpdp; tmpdp:=0pt\MFF@p;}%
}

\def\MFF@help@transf@sz{\@negargtrue
    \MFF@trick@transf{FZ}%
        {reflectedabout ((0,0),(100,100))}%
        {tempI:=tmpW; tmpW:=tmpH; tmpH:=tempI; tempI:=tmpP; tmpP:=tmpD; tmpD:=tempI;}%
        {tmptmp:=tmpwd; tmpwd:=tmpht; tmpht:=tmptmp; tmptmp:=tmpwp; tmpwp:=tmpdp; tmpdp:=tmptmp;}%
}

\def\MFF@help@transf@st{\@negargtrue
    \MFF@trick@transf{FT}%
        {reflectedabout ((0,0),(100,-100)) shifted (tmpH,tmpW)}%
        {tempI:=tmpW+tmpP; tmpW:=tmpH+tmpD; tmpH:=tempI; tmpP:=0; tmpD:=0;}%
        {tmptmp:=tmpwd+tmpwp; tmpwd:=tmpht+tmpdp; tmpht:=tmptmp; tmpwp:=0pt\MFF@p; tmpdp:=0pt\MFF@p;}%
}

% #1 - shift
\def\MFF@boxinit{%
   \MFF@writetrick{if slant>0:}
   \MFF@writetrick{\space\space\space rbXM:=hround(slant*chardp*hppp);}
   \MFF@writetrick{\space\space\space rbXP:=hround(slant*charht*hppp);}
   \MFF@writetrick{else:}
   \MFF@writetrick{\space\space\space rbXM:=hround((-slant)*charht*hppp);}
   \MFF@writetrick{\space\space\space rbXP:=hround((-slant)*chardp*hppp);}
   \MFF@writetrick{fi;}
   \if@negarg % background=yes
       \MFF@writetrick{shiftX:=rbXM+curve; rbXM:=0;}
       \MFF@writetrick{rbXP:=w+curve+rbXP+shiftX+hround(charic*hppp);}
   \else % background=no
       \MFF@writetrick{rbXM:=-curve-rbXM; rbXP:=w+curve+rbXP;}
   \fi
   \MFF@writetrick{rbYP:=body_height+curve; rbYM:=-body_depth-curve;}
   \if z\MFF@trickshadow \relax \else
      \if A\MFF@shadowstyle
           \MFF@writetrick{rbYM:=rbYM-shadowstepV; rbXP:=rbXP+shadowstepH;}
      \fi
      \if B\MFF@shadowstyle
           \MFF@writetrick{rbYP:=rbYP+shadowstepV; rbXP:=rbXP+shadowstepH;}
      \fi
      \if C\MFF@shadowstyle
           \MFF@writetrick{rbYP:=rbYP+shadowstepV; rbXM:=rbXM-shadowstepH;}
      \fi
      \if D\MFF@shadowstyle
           \MFF@writetrick{rbYM:=rbYM-shadowstepV; rbXM:=rbXM-shadowstepH;}
      \fi
   \fi
}

\def\MFF@outlineinit{\MFF@write{}%
   \MFF@writetrick{HCntSize\MFF@p:=\MFF@contourstep*hair\MFF@p;}
   \MFF@writetrick{HCntX:=hround(HCntSize\MFF@p*hppp); if (HCntX<1): HCntX:=1; fi}
   \MFF@writetrick{HCntY:=vround(HCntSize\MFF@p*hppp); if (HCntY<1): HCntY:=1; fi}
}

% #1 - pen name (HPen for background, MPen for char, SPen for shadow)
\def\MFF@patterninit#1{\MFF@write{}%
   \MFF@writetrick{#1Size\MFF@p:=\csname MFF@#1pen\endcsname *hair\MFF@p;}
   \MFF@writetrick{#1X:=hround(#1Size\MFF@p*hppp); if (#1X<1): #1X:=1; fi}
   \MFF@writetrick{#1Y:=vround(#1Size\MFF@p*hppp); if (#1Y<1): #1Y:=1; fi}
   \MFF@writetrick{path #1Path;}
   \MFF@writetrick{#1Path:=(-0.5#1X,-0.5#1Y)--(0.5#1X,-0.5#1Y)}
   \MFF@writetrick{\space\space\space --(0.5#1X,0.5#1Y)--(-0.5#1X,0.5#1Y)--cycle;}
   \MFF@writetrick{capsule_def(#1) makepen(#1Path);}
   \MFF@writetrick{#1Step\MFF@p:=\csname MFF@#1step\endcsname *hair\MFF@p;}
   \MFF@writetrick{#1StepH:=hround(#1Step\MFF@p*hppp); if (#1StepH<1): #1StepH:=1; fi}
   \MFF@writetrick{#1StepV:=vround(#1Step\MFF@p*hppp); if (#1StepV<1): #1StepV:=1; fi}
}

\def\MFF@shadowinit{\MFF@write{}%
   \def\@tempa{+}\def\@tempb{-}%
   \@tfor \@temp := \MFF@shadowstyle \do {%
      \if A\@temp \def\@tempa{+}\def\@tempb{-}\fi
      \if B\@temp \def\@tempa{+}\def\@tempb{+}\fi
      \if C\@temp \def\@tempa{-}\def\@tempb{+}\fi
      \if D\@temp \def\@tempa{-}\def\@tempb{-}\fi
   }%
   \MFF@writetrick{shadowstepH:=\@tempa hround(\MFF@shadowstep*hair\MFF@p*hppp);}%
   \MFF@writetrick{shadowstepV:=\@tempb vround(\MFF@shadowstep*hair\MFF@p*hppp);}%
}

% \@negarg = shift, #1 = picturename (Normal)
\def\MFF@trick@dochar#1{%
   \MFF@writetrick{cullit; picture #1Char;}
   \if@negarg % background=yes
         \MFF@writetrick{#1Char:=currentpicture shifted (shiftX,0);}
   \else % background=no
         \MFF@writetrick{#1Char:=currentpicture;}
   \fi
}

% #1 - input char name, #2 - output char name
\def\MFF@trick@docontour#1#2{%
   \MFF@writetrick{clearit;}
   \MFF@writetrick{currentpicture:=#1Char;}
   \MFF@writetrick{cull currentpicture keeping (1,infinity);}
   \MFF@writetrick{picture TempPict; TempPict:=currentpicture;}
   \MFF@writetrick{cull currentpicture keeping (1,1) withweight 3;}
   \MFF@writetrick{addto currentpicture also TempPict
                                      - TempPict shifted (-HCntX,0)}
   \MFF@writetrick{\space\space\space - TempPict shifted (+HCntX,0)
                                      - TempPict shifted (0,-HCntY)
                                      - TempPict shifted (0,+HCntY);}
   \MFF@writetrick{cull currentpicture keeping (1,4);}
   \MFF@writetrick{picture #2Char; #2Char:=currentpicture;}
}

% #1 - input char, #2 - output char
\def\MFF@trick@doshadow#1#2{%
   \MFF@writetrick{clearit;}
   \MFF@writetrick{currentpicture:=#1Char shifted (shadowstepH, shadowstepV);}
   \MFF@writetrick{picture ShadowPict; ShadowPict:=currentpicture;}
   \MFF@writetrick{clearit; currentpicture:=ShadowPict-#1Char;}
   \MFF@writetrick{cullit; picture #2Char; #2Char:=currentpicture;}
   \MFF@writetrick{clearit; currentpicture:=#1Char+#2Char;}
   \MFF@writetrick{cullit; picture #2BoxChar; #2BoxChar:=currentpicture;}
}

% make charactyer or shadow:
%  #1 = draw subroutine, #2 - pen name,
%  #3 = input char, #4 - output char
\def\MFF@trick@trickhelp#1#2#3#4{%
    \if z#1
        \MFF@writetrick{clearit; picture #4Char; #4Char:=currentpicture;}%
    \else
    \if Z#1
        \MFF@trick@docontour{#3}{#4}%
    \else
    \if b#1
        \MFF@writetrick{picture #4Char; #4Char:=#3Char;}%
    \else
    \if B#1
        \MFF@writetrick{picture #4Char; #4Char:=#3Char;}%
    \else
        \MFF@trick@helpdraw{#3}{R#3}{#2}{B}%
        \MFF@trick@helpdraw{R#3}{#4}{#2}{#1}%
        \MFF@checktrick{#1}{ZBVHRLDGS}{%
            \MFF@trick@docontour{#3}{OL#3}%
            \MFF@writetrick{#4Char:=#4Char + OL#3Char;}%
        }%
    \fi\fi\fi\fi
}

% black background: #1 - pen name (dummy)
\def\MFF@trick@do@b#1{\MFF@trick@do@B{#1}}
\def\MFF@trick@do@B#1{%
   \MFF@writetrick{fill (rbXM,rbYM)--(rbXP,rbYM)--(rbXP,rbYP)--(rbXM,rbYP)--cycle;}
}

% hor line background: #1 - pen name
\def\MFF@trick@do@h#1{\MFF@trick@do@H{#1}}
\def\MFF@trick@do@H#1{%
   \MFF@writetrick{for f=rbYM+0.5#1Y step #1StepV until rbYP-0.5#1Y:}
   \MFF@writetrick{\space\space\space draw (rbXM+0.5#1X,f)--(rbXP-0.5#1X,f);}
   \MFF@writetrick{endfor;}
}

% vert line background: #1 - pen name
\def\MFF@trick@do@v#1{\MFF@trick@do@V{#1}}
\def\MFF@trick@do@V#1{%
   \MFF@writetrick{for f=rbXM+0.5#1X step #1StepH until rbXP-0.5#1X:}
   \MFF@writetrick{\space\space\space draw (f,rbYM+0.5#1Y)--(f,rbYP-0.5#1Y);}
   \MFF@writetrick{endfor;}
}

% rect grid background: #1 - pen name
\def\MFF@trick@do@g#1{\MFF@trick@do@G{#1}}
\def\MFF@trick@do@G#1{\MFF@trick@do@H{#1}\MFF@trick@do@V{#1}}

% dotted grid background: #1 - pen name
\def\MFF@trick@do@d#1{\MFF@trick@do@D{#1}}
\def\MFF@trick@do@D#1{%
   \MFF@writetrick{for f=rbYM+0.5#1Y step #1StepV until rbYP-0.5#1Y:}
   \MFF@writetrick{\space for g=rbXM+0.5#1X step #1StepH until rbXP-0.5#1X:}
   \MFF@writetrick{\space\space\space draw (g,f);}
   \MFF@writetrick{\space endfor;}
   \MFF@writetrick{endfor;}
}

% slant (\) background: #1 - pen name
\def\MFF@trick@do@r#1{\MFF@trick@do@R{#1}}
\def\MFF@trick@do@R#1{%
   \MFF@writetrick{levelX:=rbXP-rbXM-#1X; levelY:=rbYP-rbYM-#1Y; f:=0;}
   \MFF@writetrick{forever:}
   \MFF@writetrick{\space\space\space exitif f>(levelX+levelY);}
   \MFF@writetrick{\space\space\space if (f<levelY) :}
   \MFF@writetrick{\space\space\space\space\space\space
                   pX:=rbXM + 0.5#1X; pY:=rbYM + 0.5#1Y + f;}
   \MFF@writetrick{\space\space\space else:}
   \MFF@writetrick{\space\space\space\space\space\space
                   pX:=rbXM + 0.5#1X + f - levelY; pY:=rbYP - 0.5#1Y;}
   \MFF@writetrick{\space\space\space fi;}
   \MFF@writetrick{\space\space\space if (f<levelX) :}
   \MFF@writetrick{\space\space\space\space\space\space
                   qX:=rbXM + 0.5#1X + f; qY:=rbYM + 0.5#1Y;}
   \MFF@writetrick{\space\space\space else:}
   \MFF@writetrick{\space\space\space\space\space\space
                   qX:=rbXP - 0.5#1X; qY:=rbYM + 0.5#1Y + f - levelX;}
   \MFF@writetrick{\space\space\space fi;}
   \MFF@writetrick{\space\space\space draw (pX,pY)--(qX,qY);}
   \MFF@writetrick{\space\space\space f:=f+#1StepV;}
   \MFF@writetrick{endfor;}
}

% slant (/) background: #1 - pen name
\def\MFF@trick@do@l#1{\MFF@trick@do@L{#1}}
\def\MFF@trick@do@L#1{%
   \MFF@writetrick{levelX:=rbXP-rbXM-#1X; levelY:=rbYP-rbYM-#1Y; f:=0;}
   \MFF@writetrick{forever:}
   \MFF@writetrick{\space\space\space exitif f>(levelX+levelY);}
   \MFF@writetrick{\space\space\space if (f<levelY) :}
   \MFF@writetrick{\space\space\space\space\space\space
                   pX:=rbXP - 0.5#1X; pY:=rbYM + 0.5#1Y + f;}
   \MFF@writetrick{\space\space\space else:}
   \MFF@writetrick{\space\space\space\space\space\space
                   pX:=rbXP - 0.5#1X - f + levelY; pY:=rbYP - 0.5#1Y;}
   \MFF@writetrick{\space\space\space fi;}
   \MFF@writetrick{\space\space\space if (f<levelX) :}
   \MFF@writetrick{\space\space\space\space\space\space
                   qX:=rbXP - 0.5#1X - f; qY:=rbYM + 0.5#1Y;}
   \MFF@writetrick{\space\space\space else:}
   \MFF@writetrick{\space\space\space\space\space\space
                   qX:=rbXM + 0.5#1X; qY:=rbYM + 0.5#1Y + f - levelX;}
   \MFF@writetrick{\space\space\space fi;}
   \MFF@writetrick{\space\space\space draw (pX,pY)--(qX,qY);}
   \MFF@writetrick{\space\space\space f:=f+#1StepV;}
   \MFF@writetrick{endfor;}
}

% slanted grid background: #1 - pen name
\def\MFF@trick@do@s#1{\MFF@trick@do@S{#1}}
\def\MFF@trick@do@S#1{\MFF@trick@do@R{#1}\MFF@trick@do@L{#1}}

% #1 - input char, #2 - output char, #3 - pen name, #4 - drawing subroutine
\def\MFF@trick@helpdraw#1#2#3#4{%
   \MFF@writetrick{clearit;}
   \if B#4 \else
       \if b#4 \else
           \if Z#4 \else
               \if z#4 \else
                   \MFF@writetrick{pickup #3;}
   \fi\fi\fi\fi
   \csname MFF@trick@do@#4\endcsname{#3}%
   \MFF@writetrick{cullit; currentpicture:=currentpicture-#1Char; cullit;}
   \MFF@writetrick{picture #2Char; #2Char:=currentpicture;}
}

% #1 - subroutine name
\def\MFF@trick@start#1{%
   \MFF@write{}\MFF@write{def #1\space = }
}

% #1 - subroutine name
\def\MFF@trick@end#1{%
   \MFF@write{enddef;}\MFF@write{}
   \MFF@write{extra_endchar := extra_endchar & "; #1";}
}

% #1 - subroutine name, #2 - transformation
% #3 - update tmpH, tmpD, tmpW, tmpP
% #4 - update tmpht, tmpdp, tmpwd, tmpwp
\def\MFF@trick@transf#1#2#3#4{%
   \MFF@trick@start{#1endchar}%
   \MFF@writetrick{picture TempPict; TempPict:=currentpicture;}
   \MFF@writetrick{clearit; currentpicture:=TempPict #2;}
   \MFF@writetrick{clearit; currentpicture:=TempPict #2;}
   \MFF@writetrick{#3}
   \MFF@trick@end{#1endchar}%
   \MFF@write{}
   \MFF@write{def #1beginchar = }
   \MFF@writetrick{#4}
   \MFF@write{enddef;}
   \MFF@write{extra_beginchar := extra_beginchar & "; #1beginchar";}
}

\def\MFF@trick@dimen{%
   \MFF@writetrick{tmpH:=vround(tmpht*hppp); tmpD:=vround(tmpdp*hppp);}
   \MFF@writetrick{tmpW:=hround(tmpwd*hppp); tmpP:=hround(tmpwp*hppp);}
}

\def\MFF@trick@shiftbox{%
   \MFF@write{}
   \MFF@write{body_depth\MFF@p:=desc_depth\MFF@p+body_height\MFF@p-asc_height\MFF@p;}
   \MFF@write{def ABCbeginchar = }
   \MFF@writetrick{tmpht:=body_height\MFF@p+curve\MFF@p; tmpdp:=body_depth\MFF@p+curve\MFF@p;}
   \MFF@writetrick{tmpwd:=charwd+charic+2*curve\MFF@p; tmpic:=0pt\MFF@p; tmpwp:=0pt\MFF@p;}
   \MFF@writetrick{if slant>0:}
   \MFF@writetrick{\space\space\space tmpwd:=tmpwd+slant*(tmpdp+tmpht);}
   \MFF@writetrick{else:}
   \MFF@writetrick{\space\space\space tmpwd:=tmpwd-slant*(tmpdp+tmpht);}
   \MFF@writetrick{fi;}
   \MFF@trick@dimen
   \MFF@write{enddef;}
   \MFF@write{extra_beginchar := "ABCbeginchar; " & extra_beginchar;}
}

\def\MFF@trick@makebox{%
   \MFF@write{}
   \MFF@write{body_depth\MFF@p:=desc_depth\MFF@p+body_height\MFF@p-asc_height\MFF@p;}
   \MFF@write{def PQRbeginchar = }
   \MFF@writetrick{tmpht:=body_height\MFF@p; tmpdp:=body_depth\MFF@p;}
   \MFF@writetrick{tmpwd:=charwd; tmpic:=charic;}
   \MFF@writetrick{if slant>0:}
   \MFF@writetrick{\space\space\space tmpwp:=curve\MFF@p+slant*tmpdp;}
   \MFF@writetrick{else:}
   \MFF@writetrick{\space\space\space tmpwp:=curve\MFF@p-slant*tmpht;}
   \MFF@writetrick{fi;}
   \MFF@trick@dimen
   \MFF@write{enddef;}
   \MFF@write{extra_beginchar := "PQRbeginchar; " & extra_beginchar;}
}

\def\MFF@trick@assignbox{%
   \MFF@write{}
   \MFF@write{def XYZbeginchar = }
   \MFF@writetrick{charht:=tmpht; chardp:=tmpdp;}
   \MFF@write{enddef;}
   \MFF@write{def XYZendchar = }
   \MFF@writetrick{charwd:=tmpwd; charic:=tmpic;}
   \MFF@write{enddef;}
   \MFF@write{extra_beginchar := extra_beginchar & "; XYZbeginchar";}
   \MFF@write{extra_endchar := extra_endchar & "; XYZendchar";}
}

%%%%%%% end MFF tricks %%%%%%%%%%%%%%%%%%%

