Initial commit

arrows_pi.asy

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+// Copyright (c) 2007, Philippe Ivaldi.
+// Last modified: Mon Dec 31 15:29:19 CET 2007
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or (at
+// your option) any later version.
+// This program is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// General Public License for more details.
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+// 02110-1301, USA.
+
+
+arrowhead EdgeHead()
+{
+  arrowhead oa;
+  oa.head=new path(path g, position position, pen p=currentpen, real size=0,
+                   real angle=arrowangle)
+    {
+      if(size == 0) size=arrowsize(p);
+      bool relative=position.relative;
+      real position=position.position.x;
+      if(relative) position=reltime(g,position);
+      path r=subpath(g,position,0.0);
+      pair x=point(r,0);
+      real t=arctime(r,size);
+      pair y=point(r,t);
+      path base=y+2*size*I*dir(r,t)--y-2*size*I*dir(r,t);
+      path left=rotate(-angle,x)*r;
+      real[] T=arrowbasepoints(base,left,r);
+      pair denom=point(right,T[1])-y;
+      real factor=denom != 0 ? length((point(left,T[0])-y)/denom) : 1;
+      path left=rotate(-angle,x)*r;
+      real[] T=arrowbasepoints(base,left,r);
+      return subpath(left,0,T[0])--y--cycle;
+    };
+  return oa;
+}
+
+arrowhead EdgeHead=EdgeHead();
+
+arrowhead EdgeHookHead(real dir=arrowdir, real barb=arrowbarb)
+{
+  arrowhead oa;
+  oa.head=new path(path g, position position, pen p=currentpen, real size=0,
+                   real angle=arrowangle)
+    {
+      if(size == 0) size=arrowsize(p);
+      angle *= arrowhookfactor;
+      bool relative=position.relative;
+      real position=position.position.x;
+      if(relative) position=reltime(g,position);
+      path r=subpath(g,position,0);
+      pair x=point(r,0);
+      real t=arctime(r,size);
+      pair y=point(r,t);
+      path base=y+2*size*I*dir(r,t)--y-2*size*I*dir(r,t);
+      path left=rotate(-angle,x)*r;
+      path right=rotate(angle,x)*r;
+      real[] T=arrowbasepoints(base,left,right);
+      pair denom=point(right,T[1])-y;
+      real factor=denom != 0 ? length((point(left,T[0])-y)/denom) : 1;
+      path left=rotate(-angle,x)*r;
+      path right=rotate(angle*factor,x)*r;
+      real[] T=arrowbasepoints(base,left,right);
+      left=subpath(left,0,T[0]);
+      right=subpath(right,T[1],0);
+      pair pl0=point(left,0), pl1=relpoint(left,1);
+      pair pr0=relpoint(right,0), pr1=relpoint(right,1);
+      pair M=(pl1+pr0)/2;
+      pair v=barb*unit(M-pl0);
+      pl1=pl1+v; pr0=pr0+v;
+      left=pl0{dir(-dir+degrees(M-pl0))}..pl1--M;
+      right=M--pr0..pr1{dir(dir+degrees(pr1-M))};
+      return left--y--cycle;
+    };
+  return oa;
+}
+arrowhead EdgeHookHead=EdgeHookHead();
+
+
+arrowhead EdgeSimpleHead(real dir=arrowdir, real barb=arrowbarb)
+{
+  arrowhead oa;
+  oa.head=new path(path g, position position, pen p=currentpen, real size=0,
+                   real angle=arrowangle)
+    {
+      if(size == 0) size=arrowsize(p);
+      bool relative=position.relative;
+      real position=position.position.x;
+      if(relative) position=reltime(g,position);
+      path r=subpath(g,position,0);
+      pair x=point(r,0);
+      real t=arctime(r,size);
+      pair y=point(r,t);
+      path base=y+2*size*I*dir(r,t)--y-2*size*I*dir(r,t);
+      path left=rotate(-angle,x)*r;
+      path right=rotate(angle,x)*r;
+      real[] T=arrowbasepoints(base,left,right);
+      pair denom=point(right,T[1])-y;
+      real factor=denom != 0 ? length((point(left,T[0])-y)/denom) : 1;
+      path left=rotate(-angle,x)*r;
+      path right=rotate(angle*factor,x)*r;
+      real[] T=arrowbasepoints(base,left,right);
+      return subpath(left,T[0],0);
+    };
+  return oa;
+}
+arrowhead EdgeSimpleHead=EdgeSimpleHead();
+
+
+private real position(position position, real size, path g, bool center)
+{
+  bool relative=position.relative;
+  real position=position.position.x;
+  if(relative) {
+    position *= arclength(g);
+    if(center) position += 0.5*size;
+    position=arctime(g,position);
+  } else if(center)
+    position=arctime(g,arclength(subpath(g,0,position))+0.5*size);
+  return position;
+}
+
+arrowbar EdgeArrows(arrowhead head=EdgeHead,real size=0, real angle=arrowangle,
+                    filltype filltype=FillDraw, position position=EndPoint,
+                    real space=infinity)
+{
+  return new bool(picture pic, path g, pen p, margin margin) {
+    pair direction;
+    real sg=sgn(dot(N,space*I*dir(g,length(g)/2)));
+    space = (space == infinity) ? 2*linewidth(p) : space/2;
+    if (sg>=0)
+      {
+        direction=-space*I*dir(g,length(g)/2);
+        sg=1;
+      }
+    else direction=space*I*dir(g,length(g)/2);
+    picture tpic;
+    tpic.add(new void (frame f, transform t) {
+        drawarrow(f,head,t*shift(inverse(t)*(-direction))*g,p,
+              size,sg*angle,filltype,position,true,margin,false);
+        drawarrow(f,head,t*shift(inverse(t)*direction)*reverse(g),p,
+              size,sg*angle,filltype,position,true,margin,false);
+      });
+    tpic.addPath(g,p);
+    real sz=size;
+    real gle=angle;
+    filltype fl=filltype;
+    addArrow(tpic,head,g,p,sz,gle,fl,position(position,size,g,false));
+    add(pic,tpic);
+    return false;
+  };
+};
+
+arrowbar EdgeArrows=EdgeArrows();