def polygonEnvelope(polygon):
# 多边形的顶点序列
partList = polygon.partList
# 两个顶点
rt = Point()
lb = Point()
rt.x = lb.x = partList[0][0].x
rt.y = lb.y = partList[0][0].y
for i in range(len(partList)):
for k in range(len(partList[i])):
if partList[i][k].x < lb.x:
lb.x = partList[i][k].x
if partList[i][k].x > rt.x:
rt.x = partList[i][k].x
if partList[i][k].y < lb.y:
lb.y = partList[i][k].y
if partList[i][k].y > rt.y:
rt.y = partList[i][k].y
envelope = Envelope()
envelope.rtPoint = rt
envelope.lbPoint = lb
return envelope
def getEnvelopeGravity(envelopeList):
#
rtPoint = Point()
lbPoint = Point()
rtPoint.x = lbPoint.x = envelopeList[0].rtPoint.x
rtPoint.y = lbPoint.y = envelopeList[0].lbPoint.y
for envelope in envelopeList:
rt = envelope.rtPoint
lb = envelope.lbPoint
if lb.x < lbPoint.x:
lbPoint.x = lb.x
if lb.y < lbPoint.y:
lbPoint.y = lb.y
if rt.x > rtPoint.x:
rtPoint.x = rt.x
if rt.y > rtPoint.y:
rtPoint.y = rt.y
envelope = Envelope()
envelope.lbPoint = lbPoint
envelope.rtPoint = rtPoint
gravity = Point()
gravity.x = (rtPoint.x + lbPoint.x) / 2
gravity.y = (rtPoint.y + lbPoint.y) / 2
return gravity, envelope
pass
def calculateGravity(pointList):
# 重心坐标
gravity = Point()
p1 = pointList[0]
p2 = pointList[1]
x1 = p1.x
y1 = p1.y
sum_x = 0
sum_y = 0
sum_area = 0
for i in range(2, len(pointList)):
x2 = p2.x
y2 = p2.y
p3 = pointList[i]
x3 = p3.x
y3 = p3.y
area = ((x2 - x1) * (y3 - y1) - (x3 - x1) * (y2 - y1)) / 2.0
sum_x += (x1 + x2 + x3) * area
sum_y += (y1 + y2 + y3) * area
sum_area += area
p2 = p3
gravity.x = sum_x / sum_area / 3.0
gravity.y = sum_y / sum_area / 3.0
return gravity
def polygonCatercorner(polygon):
# 获得外包矩形
polygon.envelope = polygonEnvelope(polygon)
# 正对角线长度
dis = pointDistance(polygon.envelope.lbPoint, polygon.envelope.rtPoint)
# 将重心移到原点
gravity = polygon.gravity
partList = []
for part in polygon.partList:
p = []
for pnt in part:
point = Point()
point.x = pnt.x - gravity.x
point.y = pnt.y - gravity.y
p.append(point)
partList.append(p)
return dis, partList
