C++ Span::SetProperties方法代码示例

	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
	}