static bool DoesIntersInterfere(const Point& pInt, const Kurve& k, double offset) {
// check that intersections don't interfere with the original kurve
Span sp;
Point dummy;
int kCheckVertex = 0;
k.Get(kCheckVertex++, sp.p0, sp.pc);
offset = fabs(offset) - geoff_geometry::TOLERANCE;
while(kCheckVertex <= k.nSpans()) {
sp.dir = k.Get(kCheckVertex++, sp.p1, sp.pc);
sp.SetProperties(true);
// check for interference
if(Dist(sp, pInt, dummy) < offset) return true;
sp.p0 = sp.p1;
}
return false; // intersection is ok
}
static Kurve eliminateLoops(const Kurve& k , const Kurve& originalk, double offset, int& ret) {
// a simple loop elimination routine based on first offset ideas in Peps
// this needs extensive work for future
// start point musn't disappear & only one valid offset is determined
//
// ret = 0 for ok
// ret = 2 for impossible geometry
Span sp0, sp1;
Point pInt, pIntOther;
Kurve ko; // eliminated output
ko = Matrix(k);
int kinVertex = 0;
while(kinVertex <= k.nSpans()) {
bool clipped = false ; // not in a clipped section (assumption with this simple method)
sp0.dir = k.Get(kinVertex, sp0.p0, sp0.pc);
sp0.ID = k.GetSpanID(kinVertex++);
if (kinVertex == 1) {
ko.Start(sp0.p0); // start point mustn't dissappear for this simple method
ko.AddSpanID(sp0.ID);
}
if (kinVertex <= k.nSpans()) { // any more?
int ksaveVertex = kinVertex ;
sp0.dir = k.Get(kinVertex, sp0.p1, sp0.pc); // first span
sp0.ID = k.GetSpanID(kinVertex++);
sp0.SetProperties(true);
int ksaveVertex1 = kinVertex; // mark position AA
if (kinVertex <= k.nSpans()) { // get the next but one span
sp1.dir = k.Get(kinVertex, sp1.p0, sp1.pc);
sp1.ID = k.GetSpanID(kinVertex++);
int ksaveVertex2 = kinVertex; // mark position BB
int fwdCount = 0;
while(kinVertex <= k.nSpans()) {
sp1.dir = k.Get(kinVertex, sp1.p1, sp1.pc); // check span
sp1.ID = k.GetSpanID(kinVertex++);
sp1.SetProperties(true);
double t[4];
int numint = sp0.Intof(sp1, pInt, pIntOther, t); // find span intersections
if(numint && sp0.p0.Dist(pInt) < geoff_geometry::TOLERANCE ) numint=0; // check that intersection is not at the start of the check span
if(numint ) {
if(numint == 2) {
// choose first intercept on sp0
Span spd = sp0;
spd.p1 = pInt;
spd.SetProperties(true);
double dd = spd.length;
spd.p1 = pIntOther;
spd.SetProperties(true);
if(dd > spd.length) pInt = pIntOther;
numint = 1;
}
ksaveVertex = ksaveVertex1 ;
clipped = true ; // in a clipped section
if(DoesIntersInterfere(pInt, originalk, offset) == false) {
sp0.p1 = pInt; // ok so truncate this span to the intersection
clipped = false; // end of clipped section
break;
}
// no valid intersection found so carry on
}
sp1.p0 = sp1.p1 ; // next
ksaveVertex1 = ksaveVertex2 ; // pos AA = BB
ksaveVertex2 = kinVertex; // mark
if((kinVertex > k.nSpans() || fwdCount++ > 25) && clipped == false) break;
}
}
if(clipped) {
ret = 2; // still in a clipped section - error
return ko;
}
ko.Add(sp0, false);
kinVertex = ksaveVertex;
}
}
ret = 0;
return ko; // no more spans - seems ok
}
