[metapost] Re: new is_clockwise routine

[Werner LEMBERG]

Here a small update to my `makeline' routine.  Some randomness is
needed for the direction of the line too.

    Werner

======================================================================

 vardef makeline primary p =
   save start, loop, d, n;
   pair start, d;

   loop := 0;
   for i = 0.5 step 1 until length p - 0.5:
     % add some randomness to get different lines for each function call
     n = uniformdeviate 0.9 - 0.45 + i;
     start := point n of p;
     d := direction n of p;
     if d <> (0, 0):
       loop := 1;
     fi;
     exitif loop = 1;
   endfor;

   if loop = 0:
     errmessage ("Cannot find a starting point on path for orientation test");
   fi;

- d := unitvector (d rotated (uniformdeviate 160 + 10));
+ d := unitvector (d rotated 90);

   % construct line orthogonal to tangent which intersects path at least once
   start - eps * d
   -- infinity * d
 enddef;