////////////////////////////////////////////////////////////////////
/// Des contributions d'OG que je remercie.
////////////////////////////////////////////////////////////////////

///// Extrémités d'une ligne quelconque sous forme de crochets

void bracket(picture pic, pair a, pair d, real s,pen p=currentpen)
{
  picture opic;
  pair ortd=s*(-d.y,d.x);
  Draw(opic,(ortd-.5d)--(-0.5d)--0.5d--(.5d+ortd),p+solid);
  add(pic,opic,a);
}
arrowbar BeginBra(real size=0, real ratiob=.3)
{
  return new bool(picture pic, path g, pen p, margin margin) {
real size=size == 0 ? barsize(p) : size;
bracket(pic,point(g,0),size*dir(g,0)*I,ratiob,p);
return true;
  };
}
arrowbar Bra(real size=0, real ratiob=.3)
{
  return new bool(picture pic, path g, pen p, margin margin) {
int L=length(g);
real size=size == 0 ? barsize(p) : size;
bracket(pic,point(g,L),size*dir(g,L)*I,-ratiob,p);
return true;
  };
}
arrowbar EndBra(real size=0, real ratiob=.3)= Bra;
arrowbar Bras(real size=0,real ratiob=.3)
{
  return new bool(picture pic, path g, pen p, margin margin) {
real size=size == 0 ? barsize(p) : size;
BeginBra(size,ratiob)(pic,g,p,margin);
EndBra(size,ratiob)(pic,g,p,margin);
return true;
  };
}
arrowbar BeginBra=BeginBra(),
Bra=Bra(),
EndBra=Bra(),
Bras=Bras();