100 lines
2.6 KiB
Python
100 lines
2.6 KiB
Python
#!/usr/bin/env python3
|
|
|
|
class Triangle():
|
|
#given segment
|
|
def __init__(self,_a,_b,_c):
|
|
self.a=_a
|
|
self.b=_b
|
|
self.c=_c
|
|
|
|
def __repr__(self):
|
|
return "Triangle:("+str(self.a)+","+str(self.b)+","+str(self.c)+")"
|
|
# Center of gravity centered on #a
|
|
# @return u how much to b
|
|
# @return v how much in the c direction
|
|
|
|
def barycentric(self,p):
|
|
#How to use barycentric coordinates
|
|
#http://www.blackpawn.com/texts/pointinpoly/default.html
|
|
ca = self.c-self.a
|
|
ba = self.b-self.a
|
|
pa = p-self.a
|
|
|
|
#Calculate dot product
|
|
dotca = ca.dot(ca)
|
|
dotcba = ca.dot(ba)
|
|
dotcpa = ca.dot(pa)
|
|
dotba = ba.dot(ba)
|
|
dotbpa = ba.dot(pa)
|
|
|
|
#Calculation of barycentric coordinates
|
|
invDenom = 1 / (dotca * dotba - dotcba * dotcba);
|
|
|
|
u = (dotba * dotcpa-dotcba*dotbpa)*invDenom
|
|
v = (dotca * dotbpa - dotcba * dotcpa) * invDenom
|
|
return u,v
|
|
|
|
# Whether there is a point inside the triangle
|
|
def isContain(self,p):
|
|
u,v=self.barycentric(p)
|
|
inkex.errormsg("\n u="+str(u)+" v="+str(v))
|
|
If #u=v=0, the same point as the triangle point
|
|
#Check if there is a point in the triangle
|
|
return (u > 0) and (v > 0) and (u + v < 1)
|
|
|
|
def toSVG(self):
|
|
return str(self.a.x)+","+str(self.a.y)+","+str(self.b.x)+","+str(self.b.y)+","+str(self.c.x)+","+str(self.c.y)
|
|
# Is the arrangement of vertices a, b, c clockwise?
|
|
|
|
def isClockWise(self):
|
|
circle=self.circumcircle()
|
|
center=circle.center
|
|
aTob=self.b-self.a
|
|
aToc=self.c-self.a
|
|
#Let's find the cross product
|
|
cross=aTob.cross(aToc)
|
|
|
|
inkex.errormsg(" cross"+str(cross))
|
|
if(cross>0):
|
|
return True
|
|
return False#Counterclockwise
|
|
|
|
def circumcircle(self):
|
|
#Find the length of each side
|
|
ab=(self.a-self.b).length()
|
|
bc=(self.b-self.c).length()
|
|
ca=(self.c-self.a).length()
|
|
s=(ab+bc+ca)/2.0;
|
|
area=math.sqrt(s*(s-ab)*(s-bc)*(s-ca));
|
|
maxlength=0
|
|
if(maxlength<ab):
|
|
maxlength=ab;longestEdge=2
|
|
if(maxlength<bc):
|
|
maxlength=bc;longestEdge=0;
|
|
if(maxlength<ca):
|
|
maxlength=ca;longestEdge=1
|
|
|
|
if longestEdge==0:
|
|
ha=2*area/bc;
|
|
angleB=math.asin(ha/ab);
|
|
angleC=math.asin(ha/ca);
|
|
angleA=math.pi-angleB-angleC;
|
|
if longestEdge== 1:
|
|
hb=2*area/ca;
|
|
angleA=math.asin(hb/ab);
|
|
angleC=math.asin(hb/bc);
|
|
angleB=math.pi-angleC-angleA;
|
|
if longestEdge== 2:
|
|
hc=2*area/ab;
|
|
angleB=math.asin(hc/bc);
|
|
angleA=math.asin(hc/ca);
|
|
angleC=math.pi-angleA-angleB;
|
|
|
|
A = math.sin(2.0*angleA);
|
|
B = math.sin(2.0*angleB);
|
|
C = math.sin(2.0*angleC);
|
|
center=Vertex((self.a.x * A + self.b.x * B + self.c.x * C) / (A+B+C),
|
|
(self.a.y * A + self.b.y * B + self.c.y * C) / (A+B+C));
|
|
rad=bc / math.sin(angleA) / 2.0
|
|
return Circle(center,rad);
|