def arc_insert(self, p):
if self.arc is None:
self.arc = Arc(p)
else:
# find the current arcs at p.y
i = self.arc
while i is not None:
flag, z = self.intersect(p, i)
if flag:
# new parabola intersects arc i
flag, zz = self.intersect(p, i.pnext)
if (i.pnext is not None) and (not flag):
i.pnext.pprev = Arc(i.p, i, i.pnext)
i.pnext = i.pnext.pprev
else:
i.pnext = Arc(i.p, i)
i.pnext.s1 = i.s1
# add p between i and i.pnext
i.pnext.pprev = Arc(p, i, i.pnext)
i.pnext = i.pnext.pprev
i = i.pnext # now i points to the new arc
# add new half-edges connected to i's endpoints
seg = Segment(z)
self.output.append(seg)
i.pprev.s1 = i.s0 = seg
seg = Segment(z)
self.output.append(seg)
i.pnext.s0 = i.s1 = seg
# check for new circle events around the new arc
self.check_circle_event(i, p.x)
self.check_circle_event(i.pprev, p.x)
self.check_circle_event(i.pnext, p.x)
return
i = i.pnext
# if p never intersects an arc, append it to the list
i = self.arc
while i.pnext is not None:
i = i.pnext
i.pnext = Arc(p, i)
# insert new segment between p and i
x = self.x0
y = (i.pnext.p.y + i.p.y) / 2.0;
start = Point(x, y)
seg = Segment(start)
i.s1 = i.pnext.s0 = seg
self.output.append(seg)
def process_event(self):
# get next event from circle pq
e = self.event.pop()
if e.valid:
# start new edge
s = Segment(e.p)
self.output.append(s)
# remove associated arc (parabola)
a = e.a
if a.pprev is not None:
a.pprev.pnext = a.pnext
a.pprev.s1 = s
if a.pnext is not None:
a.pnext.pprev = a.pprev
a.pnext.s0 = s
# finish the edges before and after a
if a.s0 is not None: a.s0.finish(e.p)
if a.s1 is not None: a.s1.finish(e.p)
# recheck circle events on either side of p
if a.pprev is not None: self.check_circle_event(a.pprev, e.x)
if a.pnext is not None: self.check_circle_event(a.pnext, e.x)
def process_event(self): #NAMES!!! WHAT THE HELL DO THEY MEAN!!!
# get next event from circle pq
event = self.event.pop() #e? Thats an event
if event.valid:
# start new edge
circleCenter = Segment(event.point)
self.output.append(circleCenter)