通过一点找最近线段

pair<SkPoint,SkPoint> GetPioneerSegment(SkPoint pt,vector<pair<SkPoint,SkPoint>> vectorOfSemgents)
{
pair<SkPoint , SkPoint > reValue;
reValue.first = SkPoint::Make(0,0);
reValue.second = SkPoint::Make(0,0);
if (vectorOfSemgents.size() == 0)
return reValue;

vector<double> vectorOfLength;
for (int i = 0 ; i < vectorOfSemgents.size() ; i++ )
{
Wm5::Vector2d v_first = Wm5::Vector2d(vectorOfSemgents[i].first.fX,
vectorOfSemgents[i].first.fY);
Wm5::Vector2d v_second = Wm5::Vector2d(vectorOfSemgents[i].second.fX,
vectorOfSemgents[i].second.fY);
Wm5::Segment2d	segment(v_first,v_second);
Wm5::DistPoint2Segment2d distPt2Segment(Wm5::Vector2d(pt.fX,pt.fY),segment);
vectorOfLength.push_back(distPt2Segment.Get());
}

int nIndex = -1;
if (vectorOfLength.size() == 0)
return reValue;
double minLength = *min_element(vectorOfLength.begin(),vectorOfLength.end());
for ( int i = 0 ; i < vectorOfLength.size() ; i++)
{
if (vectorOfLength[i] == minLength )
nIndex = i;
}
reValue = vectorOfSemgents[nIndex];
return reValue;
}