CvContourPolygon *cvPolygonContourConvexHull(CvContourPolygon const *p)
{
CV_FUNCNAME("cvPolygonContourConvexHull");
__CV_BEGIN__;
{
CV_ASSERT(p!=NULL);
if (p->size()<=3)
{
return new CvContourPolygon(p->begin(), p->end());
}
deque<CvPoint> dq;
if (cvCrossProductPoints((*p)[0], (*p)[1], (*p)[2])>0)
{
dq.push_back((*p)[0]);
dq.push_back((*p)[1]);
}
else
{
dq.push_back((*p)[1]);
dq.push_back((*p)[0]);
}
dq.push_back((*p)[2]);
dq.push_front((*p)[2]);
for (unsigned int i=3; i<p->size(); i++)
{
int s = dq.size();
if ((cvCrossProductPoints((*p)[i], dq.at(0), dq.at(1))>=0) && (cvCrossProductPoints(dq.at(s-2), dq.at(s-1), (*p)[i])>=0))
continue; // TODO Optimize.
while (cvCrossProductPoints(dq.at(s-2), dq.at(s-1), (*p)[i])<0)
{
dq.pop_back();
s = dq.size();
}
dq.push_back((*p)[i]);
while (cvCrossProductPoints((*p)[i], dq.at(0), dq.at(1))<0)
dq.pop_front();
dq.push_front((*p)[i]);
}
return new CvContourPolygon(dq.begin(), dq.end());
}
__CV_END__;
}
double cvDistanceLinePoint(CvPoint const &a, CvPoint const &b, CvPoint const &c, bool isSegment)
{
if (isSegment)
{
double dot1 = cvDotProductPoints(a, b, c);
if (dot1>0) return cvDistancePointPoint(b, c);
double dot2 = cvDotProductPoints(b, a, c);
if(dot2>0) return cvDistancePointPoint(a, c);
}
return fabs(cvCrossProductPoints(a,b,c)/cvDistancePointPoint(a,b));
}