vw::Vector2 tangent(PointContour c, PointContour::iterator p) {
vw::Vector2 t;
PointContour::iterator b = c.begin();
PointContour::iterator e = --(c.end());
if (p == b) {
t = *(++p) - *(--p);
} else if (p == e) {
t = *(--p) - *(++p);
} else {
vw::Vector2 v1, v2;
v1 = *(--p) - *(++p);
v2 = *p - *(++p);
t = vw::Vector2((v1[0] + v2[0])/2.0, (v1[1] + v2[1])/2.0);
}
normalize(t);
return t;
}
/*
* FitCurve :
* Fit a Bezier curve to a set of digitized points
*/
BezierContour FitCurve(PointContour &contour, double error)
{
Vector2 tHat1, tHat2; /* Unit tangent vectors at endpoints */
PointContour::iterator iter;
BezierContour bezContour;
int i = 0;
int nPts = contour.size();
Point2 *d = (Point2 *)malloc(nPts * sizeof(Point2));
for (iter = contour.begin(); iter != contour.end(); ++iter) {
Point2 a;
a.x = (*iter)[0]; a.y = (*iter)[1];
d[i++] = a;
}
tHat1 = ComputeLeftTangent(d, 0);
tHat2 = ComputeRightTangent(d, nPts - 1);
FitCubic(d, 0, nPts - 1, tHat1, tHat2, error, bezContour);
free(d);
return bezContour;
}
inline bool closed(PointContour& c) {
return c.front() == c.back();
}
bool join(PointContour& c1, PointContour& c2) {
ContourPoint c1_front = c1.front();
ContourPoint c1_back = c1.back();
ContourPoint c2_front = c2.front();
ContourPoint c2_back = c2.back();
if (c1_back == c2_front) {
c1.splice(c1.end(), c2);
}
else if (c1_front == c2_back) {
c1.splice(c1.begin(), c2);
}
else if (c1_back == c2_back) {
if (c2.size() < c1.size()) {
c2.reverse();
c1.splice(c1.end(), c2);
}
else {
c1.reverse();
c1.splice(c1.begin(), c2);
}
}
else if (c1_front == c2_front) {
if (c2.size() < c1.size()) {
c2.reverse();
c1.splice(c1.begin(), c2);
}
else {
c1.reverse();
c1.splice(c1.end(), c2);
}
}
else
return false;
return true;
}
