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%D \module
%D [ file=mp-node.mpiv,
%D version=1998.02.15,
%D title=\CONTEXT\ \METAPOST\ graphics,
%D subtitle=Node Based Graphics,
%D author=Alan Braslau,
%D date=\currentdate,
%D copyright={Alan Braslau & \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 Ths crossing macros were written as part of this module but as they
%D can be of use elsewhere they are defined in mp-tool.
if known context_node : endinput ; fi ;
boolean context_node ; context_node := true ;
% returns a pair suffix if the path is unknown
vardef makenode@#(suffix p)(text t) =
save i, b ; numeric i ; string b ;
for a = t :
if unknown i : % first argument is the index
i = a ;
if isarray p :
%
% note that one needs to declare "path p[] ; picture p[]pic[] ;"
% before calling node() if one is to use a pseudo-array for p
% because "picture p1.pic[] ;" is not a valid syntax!
%
% The following works, but is a bit awkward...
%
b := prefix p ;
if not picture p.pic[i] : scantokens("picture " & b & "[]pic[] ;") ; fi
if not pair p.pos[i] : scantokens("pair " & b & "[]pos[] ;") ; fi
else :
if not picture p.pic[i] : picture p.pic[] ; fi
if not pair p.pos[i] : pair p.pos[] ; fi
fi
else :
if known p.pic[i] :
addto p.pic[i] also
else :
p.pic[i] :=
fi
if picture a : a
elseif string a : textext@#(a)
elseif numeric a : textext@#(decimal a)
elseif ((boolean a) and a) : image(draw origin)
else : nullpicture
fi ;
fi
endfor
p.pos[i] if known p : := point i of p ; fi
enddef ;
% returns a picture
vardef node@#(suffix p)(text t) =
if pair makenode@#(p)(t) :
% nop: gobble the function return.
fi
for a = t :
if (unknown p) and (known p.pos[a]) :
makenodepath(p) ;
fi
if known p.pic[a] :
p.pic[a] if known p : shifted point a of p fi
else :
nullpicture
fi
exitif true ;
endfor
enddef ;
% returns a path
vardef fromto@#(expr d)(suffix p)(expr f)(suffix q)(text s) =
save r, t, l ;
path r[] ; numeric t ; picture l ;
for a = s :
if unknown t :
t = a ;
if (unknown p) and (known p.pos[f]) :
makenodepath(p) ;
fi
if (unknown q) and (known q.pos[t]) :
makenodepath(q) ;
fi
r0 = if ((not numeric d) and
(point f of p = point f of q) and
(point t of p = point t of q)) :
subpath (f,t) of p
else :
point f of p -- point t of q
fi ;
save deviation ; numeric deviation ;
deviation := if numeric d: d else: 0 fi ;
r1 = if deviation=0 : r0
else :
point 0 of r0 ..
unitvector direction .5length r0 of r0 rotated 90
scaled deviation * arclength r0
shifted point .5length r0 of r0 ..
point length r0 of r0
fi ;
else :
if known l :
addto l also
else :
l :=
fi
if picture a : a
elseif string a : textext@#(a)
elseif numeric a : textext@#(decimal a)
elseif ((boolean a) and a) : image(draw origin withpen currentpen scaled 4)
else : nullpicture
fi ;
fi
endfor
r2 = r1
if known p.pic[f if cycle p: mod length p fi] :
cutbefore boundingbox (p.pic[f if cycle p: mod length p fi] shifted point f of p)
fi
if known q.pic[t if cycle q: mod length q fi] :
cutafter boundingbox (q.pic[t if cycle q: mod length q fi] shifted point t of q)
fi
;
if known l :
l := l shifted point .5length r2 of r2 ;
draw l ;
(r2 if str @# = "" : crossingunder l fi)
else :
r2
fi
enddef ;
% returns pair: bounding point of the node picture
vardef nodeboundingpoint@#(suffix p)(expr i) =
if known p.pic[i] :
boundingpoint@#(p.pic[i])
else :
origin
fi
enddef ;
% returns pair: scaled laboff direction
vardef relative@#(expr s) =
(mfun_laboff@# scaled s)
enddef ;
% returns pair: vector between nodes (+ optional scale)
vardef betweennodes@#(suffix p)(expr f)(suffix q)(text s) =
save t ; numeric t ;
for a = s :
if unknown t :
t = a ;
nodeboundingpoint@#(q,t) + nodeboundingpoint@#(p,f)
else :
+ relative@#(a)
fi
endfor
enddef ;
% build a path from the node positions.
% Must be continuous in index starting at 0.
vardef makenodepath(suffix p) =
if unknown p :
save i ; i = -1 ;
p = forever : exitif unknown p.pos[incr i] ;
p.pos[i] --
endfor cycle ;
fi
enddef ;
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