def __sub__(self, other):
"""
Subtraction of polygons
"""
sequence = []
# get raw points lists without duplication first-last
points = [dict([["point",p], ["kind",k], ["visited", False]]) for p, k in self.points[:-1]]
otherPoints = [dict([["point",p], ["kind",k], ["visited", False]]) for p, k in other.points[:-1]]
tmp = [BravePoint(p,k) for p, k in self.points[:-1]]
tmp2 = [BravePoint(p,k) for p, k in other.points[:-1]]
tmp2.reverse() # useful
points = LinkedList()
points.load(tmp)
points.setEndless(True)
otherPoints = LinkedList()
otherPoints.load(tmp2)
otherPoints.setEndless(True)
#pprint(tmp)
#pprint(tmp2)
p = points.first
firstStep = True
while p is not points.first or firstStep:
firstStep = False
d = p.data
if d.kind != Kind.outgoing or d.visited:
p = p.next
continue
# brave new polygon!
newbies = getPointsUntilExit(points, otherPoints, p.data)
#print("newbies= ", newbies)
sequence.append(newbies)
#print "sequence= ", sequence
points.setEndless(False)
otherPoints.setEndless(False)
#pprint({'points': points.toList(), 'otherPoints': otherPoints.toList()})
result = []
for lol in sequence:
tmp = [bp.point for bp in lol]
kinds = [Kind.neutral]*len(tmp)
poly = Poly(points=zip(tmp, kinds))
result.append(poly)
return result
