int TwoCircleTangents(Circle A,Circle B,vector<Point>& a,vector<Point>& b)
{
int cnt = 0;
if(A.r < B.r) { swap(A,B); swap(a,b); }
int d2 = (A.c.x-B.c.x)*(A.c.x-B.c.x) + (A.c.y-B.c.y)*(A.c.y-B.c.y);
int rdiff = A.r-B.r;
int rsum = A.r+B.r;
if(d2 < rdiff*rdiff) return 0;
double base = atan2(B.c.y-A.c.y,B.c.x-A.c.x);
if(d2 == 0 && A.r == B.r) return -1;
if(d2 == rdiff*rdiff)
{
a.push_back(A.getPoint(base)) ; b.push_back(B.getPoint(base)); cnt++;
return 1;
}
double ang = acos((A.r-B.r) / sqrt(d2));
a.push_back(A.getPoint(base+ang)); b.push_back(B.getPoint(base+ang)); cnt++;
a.push_back(A.getPoint(base-ang)); b.push_back(B.getPoint(base-ang)); cnt++;
if(d2 == rsum*rsum)
{
a.push_back(A.getPoint(base)); b.push_back(B.getPoint(PI+base)); cnt++;
}
else if(d2 > rsum*rsum)
{
double ang = acos((A.r+B.r) / sqrt(d2));
a.push_back(A.getPoint(base+ang)); b.push_back(B.getPoint(PI+base+ang)); cnt++;
a.push_back(A.getPoint(base-ang)); b.push_back(B.getPoint(PI+base-ang)); cnt++;
}
return cnt;
}
int getTangents(Circle A, Circle B, Point* a, Point* b)
{
int cnt = 0;
if(A.r < B.r) { swap(A, B); swap(a, b); }
int d2 = (A.x-B.x)*(A.x-B.x) + (A.y-B.y)*(A.y-B.y);
int rdiff = A.r-B.r;
int rsum = A.r+B.r;
if(d2 < rdiff*rdiff) return 0;
double base = atan2(B.y-A.y, B.x-A.x);
if(d2 == 0 && A.r == B.r) return -1; // 无限多条切线
if(d2 == rdiff*rdiff)
{ // 内切，1条切线
a[cnt] = A.getPoint(base); b[cnt] = B.getPoint(base); cnt++;
return 1;
}
// 有外共切线
double ang = acos((A.r-B.r) / sqrt(d2));
a[cnt] = A.getPoint(base+ang); b[cnt] = B.getPoint(base+ang); cnt++;
a[cnt] = A.getPoint(base-ang); b[cnt] = B.getPoint(base-ang); cnt++;
if(d2 == rsum*rsum)
{ // 一条内共切线
a[cnt] = A.getPoint(base); b[cnt] = B.getPoint(PI+base); cnt++;
}
else if(d2 > rsum*rsum)
{ // 两条内共切线
double ang = acos((A.r+B.r) / sqrt(d2));
a[cnt] = A.getPoint(base+ang); b[cnt] = B.getPoint(PI+base+ang); cnt++;
a[cnt] = A.getPoint(base-ang); b[cnt] = B.getPoint(PI+base-ang); cnt++;
}
return cnt;
}
int TwoCirclePoint(Circle C1,Circle C2,vector<Point>& res) //求２圆交点，返回交点数（特别的－１表示２圆重合，无穷个交点)
{
double d = Length(C1.c-C2.c);
if(dcmp(d) == 0)
{
if(dcmp(C1.r-C2.r) == 0) return -1;
return 0;
}
if(dcmp(C1.r + C2.r - d) < 0) return 0;
if(dcmp(fabs(C1.r-C2.r) - d) > 0) return 0;
double a = Angle(C2.c-C1.c);
double da = acos((C1.r*C1.r+d*d-C2.r*C2.r) / (2*C1.r*d));
Point p1 = C1.getPoint(a-da),p2 = C1.getPoint(a+da);
res.push_back(p1);
if(p1 == p2) return 1;
res.push_back(p2);
return 2;
}
void showTemplate(const MinutiaeTemplate & mt, double T, const char *name)
{
Circle c;
c.setT(T);
c.getCenter(mt);
c.fromTemplate(mt);
Mat mat(500, 500, CV_8UC3, Scalar(255, 255, 255));
int offsetx = 100, offsety = 100, R = c.getR();
circle(mat,Point(c.getCenterX()+offsetx,c.getCenterY()+offsety),R,Scalar(0,255,0));
for(int i = 1; i < c.getSize(); i+=2)
{
double p1 = c.getPoint(i-1);
double p2 = c.getPoint(i);
line(mat,Point(R*cos(p1)+c.getCenterX()+offsetx,R*sin(p1)+c.getCenterY()+offsety),
Point(R*cos(p2)+c.getCenterX()+offsetx,R*sin(p2)+c.getCenterY()+offsety),
Scalar(255,0,0));
}
for(int i = 0; i < mt.getSize(); i++)
circle(mat,Point(mt.getMinutia(i).getX()+offsetx,mt.getMinutia(i).getY()+offsety),3,Scalar(0,0,255),CV_FILLED);
imshow(name,mat);
}