simplifies a list a points

simplify_path.py

def simplify_path(p):
   direction = p[1][0]-p[0][0], p[1][1]-p[0][1]
   yield p[0]
   current = p[1]
   if len(p)>2:
       for pos in p[2:]:
           rdir = pos[0]-current[0], pos[1]-current[1]
           if direction != rdir:
               yield current
           current = pos
   yield p[-1]