// return how many lines are removed
guint Printlines::makeIntoArc(guint fromind, guint toind)
{
if (toind < fromind || toind+1 > lines.size()) return 0;
Vector2d P = lines[fromind].from;
Vector2d Q = lines[toind].to;
// center perp of start -- endpoint:
Vector2d connp1,connp2;
center_perpendicular(P, Q, connp1, connp2);
// center perp of midpoint -- endpoint:
guint midind = (toind+fromind)/2;
Vector2d midp1,midp2;
center_perpendicular(lines[midind].from, lines[toind].to, midp1, midp2);
// intersection = center
Vector2d center, ip;
double t0, t1;
int is = intersect2D_Segments(connp1, connp2, midp1, midp2,
center, ip, t0,t1);
if (is > 0) {
double angle = angleBetween(P-center, Q-center);
bool ccw = isleftof(center, lines[fromind].from, lines[fromind].to);
if (!ccw) angle = -angle;
if (angle<=0) angle+=2*M_PI;
short arctype = ccw ? -1 : 1;
PLine newline(P, Q, lines[fromind].speed, lines[fromind].feedrate,
arctype, center, angle);
lines[fromind] = newline;
lines.erase(lines.begin()+fromind+1, lines.begin()+toind+1);
return toind-fromind;
} else cerr << "no Intersection of arc perpendiculars!" << endl;
return 0;
}
/*
* Iterate the vertices, and calculate whether this
* shape is a hole or enclosed, based on whether the
* segment normals point outward (a hole) or inward
* (enclosing)
*/
void Poly::calcHole() const // hole is mutable
{
if(vertices.size() < 3)
return; // hole is undefined
Vector2d p(-INFTY, -INFTY);
int v=0;
center = Vector2d(0,0);
Vector2d q;
for(size_t vert=0;vert<vertices.size();vert++)
{
q = vertices[vert];
center += q;
if(q.x() > p.x())
{
p = q;
v=vert;
}
else if(q.x() == p.x() && q.y() > p.y())
{
p.y() = q.y();
v=vert;
}
}
center /= vertices.size();
// we have the x-most vertex (with the highest y if there was a contest), v
Vector2d V1 = getVertexCircular(v-1);
Vector2d V2 = getVertexCircular(v);
Vector2d V3 = getVertexCircular(v+1);
// Vector2d Va=V2-V1;
// Vector2d Vb=V3-V2;
hole = isleftof(V2, V3, V1); //cross(Vb,Va) > 0;
holecalculated = true;
}
long double angleBetween(const Vector2d &V1, const Vector2d &V2)
{
long double dotproduct = V1.dot(V2);
long double length = V1.length() * V2.length();
if (length==0) return 0;
long double quot = dotproduct / length;
if (quot > 1 && quot < 1.0001) quot = 1;
if (quot < -1 && quot > -1.0001) quot = -1;
long double result = acosl( quot ); // 0 .. pi
if (isleftof(Vector2d(0,0), V2, V1))
result = -result;
return result;
}
