拓扑多边形生成算法（C++源码）二代码篇

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本文介绍了一种拓扑多边形生成算法，并提供了详细的C++实现代码。该算法能够从输入的数据图像中构建拓扑多边形，并输出相关的拓扑信息。

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这里主要是补充拓扑多边形生成算法（C++源码）一的代码内容和代码运行情况，希望给大家学习多边形生成算法带来帮助！

源程序下载地址：http://download.youkuaiyun.com/source/1870862

1、读入数据图像（程序中不会显示图像，图像的点和弧段信息保存在文本中）

2、在屏幕上输出拓扑信息

补充代码：

/* *函数功能：计算两条直线逆时针方向的夹角 *参数信息： start：起始点；inf：拐点；end：终止点 *返回值：两条直线之间的夹角（弧度）； */ double CreatePolygons::AngleOfTwoArcs(Point* start, Point* inf, Point* end) { double aa = ( start->X - inf->X ) * ( start->X - inf->X ) + ( start->Y - inf->Y ) * ( start->Y - inf->Y ); double bb = ( inf->X - end->X ) * ( inf->X - end->X ) + ( inf->Y - end->Y ) * ( inf->Y - end->Y ); double cc = ( start->X - end->X ) * ( start->X - end->X ) + ( start->Y - end->Y ) * ( start->Y - end->Y ); double cosValue = ( aa + bb - cc ) / ( 2 * sqrt( aa ) * sqrt( bb ) ); double angle = acos( cosValue ); double coeff1 = 0.0f, coeff2 = 0.0f; if ( start->Y != inf->Y ) { coeff1 = ( double )( inf->X - start->X ) / ( double )( start->Y - inf->Y ); coeff2 = ( double )( start->X * inf->Y - inf->X * start->Y ) / ( double )( start->Y - inf->Y ); if ( start->Y > inf->Y ) { if ( end->X + coeff1 * end->Y + coeff2 <= 0 ) { return angle; } else { return ( PI * 2 - angle ); } } else if ( start->Y < inf->Y ) { if ( end->X + coeff1 * end->Y + coeff2 <= 0 ) { return ( PI * 2 - angle ); } else { return angle; } } } else if ( start->Y == inf->Y ) { if ( inf->X > start->X ) { if ( end->Y < start->Y ) { return angle; } else { return ( PI * 2 - angle ); } } else if ( inf->X < start->X ) { if ( end->Y < start->Y ) { return ( PI * 2 - angle ); } else { return angle; } } } return 10.0f; } void CreatePolygons::MainCreatePolygons(void) { //建立点-弧段关系，而弧段-点关系在函数OpenFile已经建立 this->BuildPointArcs(); //多边形自动够构建算法 for (int i = 0; i < (int)Arcs.size(); i++) { Arc* arc = Arcs[i]; if (arc->TimeOfSearch == 0) { Buildpolygons(arc); } } } bool CreatePolygons::OpenFile(const char *filename) { FILE* fp; char ss[20]; int pNum, lNum; char lcode[20]; int code; float left_x, left_y; if((fp=fopen(filename,"r"))==0) return false; //读入点 fscanf(fp,"%s",ss); if(strcmp(ss,"Point:")!=0) { cout << "文件格式不正确!" << endl; return false; } fscanf(fp,"%d",&pNum); for(int i=0;i<pNum;i++) { fscanf(fp,"%ld%f%f",&code,&left_x,&left_y); cout << code << " " << left_x << " " << left_y << endl; Point *point = new Point; point->ID = code; point->X = left_x; point->Y = left_y; Points.push_back(point); } //读入弧段 fscanf(fp,"%s",ss); if(strcmp(ss,"Line:")!=0) { cout << "文件格式不正确!" << endl; return false; } fscanf(fp,"%d",&lNum); cout << "共有弧段：" << lNum << endl; for(int i=0;i<lNum;i++) { Arc *arc = new Arc; fscanf(fp,"%s%d",lcode,&pNum); cout << "弧段编号：" << lcode<< "弧段上点的个数："<< pNum << endl; string str(lcode); arc->ID = str; arc->Direction = 1; arc->TimeOfSearch = 0; for(int j=0;j<pNum;j++) { int pp; fscanf(fp,"%d",&pp); cout << pp << " "; Point *p = SearchPointbyID(pp); if (p != NULL) { arc ->Points.push_back(p); } else { cout << "没有找到合适的点！"<<endl; } } cout << endl; Arcs.push_back(arc); } fclose(fp); return true; } Arc* CreatePolygons::GetNextArc(Arc* cuarc) { Point *start, *start0; PointArcs* PtArcs; double hudu; Arc* NextArc = cuarc; Angles.clear();//清空所有的角度 if (cuarc->Direction == 1) { start0 = *(cuarc->Points.end() -2); //起始点 start = *(cuarc->Points.end() - 1); PtArcs = SearchPtArcsByPt(start); for (int i = 0; i < (int)PtArcs->arcs.size(); i++) { if ((strcmp(cuarc->ID.c_str(),PtArcs->arcs[i]->ID.c_str())!= 0) && (PtArcs->arcs[i]->TimeOfSearch < 2)) { Angle angle; Point *sta, *end; sta = *(PtArcs->arcs[i]->Points.begin()); end = *(PtArcs->arcs[i]->Points.end() - 1); //确认扩展弧段 if (sta->ID == start->ID)//准扩展弧段以第一记录开始,方向与当前弧段相反 { sta = *(PtArcs->arcs[i]->Points.begin() + 1); hudu = AngleOfTwoArcs(start0, start, sta); angle.Direction = 1; } else if(end->ID == start->ID)//准扩展弧段以最后记录开始，方向与当前弧段一样 { end = *(PtArcs->arcs[i]->Points.end() - 2); hudu = AngleOfTwoArcs(start0, start, end); angle.Direction = -1; } //angle.Direction = cuarc->Direction; angle.angle = hudu; angle.arcs = PtArcs->arcs[i]; Angles.push_back(angle); } } } else if(cuarc->Direction == -1) { start0 = *(cuarc->Points.begin() + 1); //起始点 start = *(cuarc->Points.begin()); PtArcs = SearchPtArcsByPt(start); for (int i = 0; i < (int)PtArcs->arcs.size(); i++) { if ((strcmp(cuarc->ID.c_str(), PtArcs->arcs[i]->ID.c_str()) != 0) && (PtArcs->arcs[i]->TimeOfSearch < 2)) { Angle angle; Point *sta, *end; sta = *(PtArcs->arcs[i]->Points.begin()); end = *(PtArcs->arcs[i]->Points.end() - 1); //确认扩展弧段 if (sta->ID == start->ID)//准扩展弧段以第一记录开始,方向与当前弧段相反 { sta = *(PtArcs->arcs[i]->Points.begin() + 1); hudu = AngleOfTwoArcs(start0, start, sta); angle.Direction = 1; } else if(end->ID == start->ID)//准扩展弧段以最后记录开始，方向与当前弧段一样 { end = *(PtArcs->arcs[i]->Points.end() - 2); hudu = AngleOfTwoArcs(start0, start, end); angle.Direction = -1; } angle.angle = hudu; angle.arcs = PtArcs->arcs[i]; Angles.push_back(angle); } } } else { cout << "弧段的方向错误！" << endl; } if (Angles.size() == 0) { return NextArc;//没有任何夹角时返回弧段本身 } MinAngle = GetMinAngle(Angles);//得到扩展弧段的ID NextArc = MinAngle.arcs; return NextArc; } void CreatePolygons::Createpolygons(Arc* cuarc) { vector<Polygon*> polygons;//记录多边形图 Polygon* polygon = BuildOnePolygon(cuarc); vector<Point*> lpoints; lpoints = GetPlPoints(polygon); polygon->Points = lpoints; polygon->area = abs(GetArea(lpoints));//计算面积 polygons.push_back(polygon); for (int i = 0; i < (int)Arcs.size(); i++) { if (Arcs[i]->TimeOfSearch == 1) { Arcs[i]->Direction *= -1; polygon = BuildOnePolygon(Arcs[i]); if (polygon == NULL) { return; } //计算多边形面积 vector<Point*> points; points = GetPlPoints(polygon); polygon->area = abs(GetArea(points)); polygon->Points = points; polygons.push_back(polygon); i = 0;//每次都从第一个弧段搜索 } } //一个多边形图构建完毕，还要去除面积最大的多边形（不符合） this->RemoveMaxPolygon(polygons); for (int i = 0; i < (int)polygons.size(); i++) { polygons[i]->ID = Pid; Pid++; Polygons.push_back(polygons[i]); } } Polygon* CreatePolygons::CreateOnePolygon(Arc* cuarc) { Polygon* polygon = new Polygon; Arc * NextArc; NextArc = GetNextArc(cuarc); ArcDir *arcpoint0 = new ArcDir; arcpoint0->arcs = cuarc; arcpoint0->Direction = cuarc->Direction; //将多边形的起始弧段添加到多边形中 polygon->ArcPts.push_back(arcpoint0); if (NextArc == NULL) { delete polygon; return NULL; } while (1) { if ((NextArc != cuarc) && (NextArc->TimeOfSearch < 2)) { NextArc->Direction = MinAngle.Direction; //扩展弧段的遍历次数增加,除去对第二次起始弧段的遍历 NextArc->TimeOfSearch += 1; ArcDir *arcpoint = new ArcDir; arcpoint->arcs = NextArc; arcpoint->Direction = NextArc->Direction; polygon->ArcPts.push_back(arcpoint); NextArc = GetNextArc(NextArc); } else { break;//一个多边形构建完毕 } } cuarc->TimeOfSearch += 1;//起始弧段的遍历次数增加 return polygon; } void CreatePolygons::RemoveMaxPolygon(vector<Polygon*>& Polygons) { vector<Polygon*>::iterator maxiter; double max; maxiter = Polygons.begin(); max = (*maxiter)->area; for(vector<Polygon*>::iterator iter = Polygons.begin()+1; iter != Polygons.end(); iter++ ) { if (max <= (*iter)->area) { maxiter = iter; max = (*iter)->area; } } Polygons.erase(maxiter); } //面积为正可以判断多边型正面，面积为负表示多边形背面 double CreatePolygons::GetArea(vector<Point*> pPoint) { double S = 0; int nNum = (int)pPoint.size(); for(int i = 0; i < nNum - 1; i++) S+=pPoint[i]->X * pPoint[i+1]->Y - pPoint[i+1]->X * pPoint[i]->Y; S += pPoint[nNum-1]->X * pPoint[0]->Y - pPoint[0]->X * pPoint[nNum-1]->Y; S /= 2.0; return S; } void CreateTopology::CreatePolArc(vector<Polygon*> Polygons) { for (int i = 0; i < (int)Polygons.size(); i++) { TPolArc* tpolarc = new TPolArc; tpolarc->PolID = Polygons[i]->ID; for (int j = 0; j < (int)Polygons[i]->ArcPts.size();j++) { string id = Polygons[i]->ArcPts[j]->arcs->ID; tpolarc->ArcID.push_back(id); } if ((int)Polygons[i]->ArcPts.size() == 1) { Arc * arc = Polygons[i]->ArcPts[0]->arcs;//仅有一多边形可能为岛 //取多边形上任意一点，判断是否在其他多边形中 if (PtInisland(Polygons, Polygons[i])) { ModifyPol(islandinfo.OutPolID); } } PolArc.push_back(tpolarc); } } bool CreateTopology::PtInisland(std::vector<Polygon*> Polygons, Polygon* polygon) { bool flag = false; Point* point = polygon->ArcPts[0]->arcs->Points[0]; for (int i = 0; i < (int)Polygons.size(); i++) { if (polygon->ID != Polygons[i]->ID) { vector<Point*> points = Polygons[i]->Points; bool n = PtInRegion(point, points); if (n)//在多边形内部的情况 { string id("-"); id += polygon->ArcPts[0]->arcs->ID; islandinfo.BeforeID = polygon->ArcPts[0]->arcs->ID; islandinfo.AfterID = id; islandinfo.OutPolID = Polygons[i]->ID; islandinfo.InPolID = polygon->ID; flag = true; break; } } } return flag; } //判断出岛，需要将岛的弧段添加到包含的多边形弧段关系中 void CreateTopology::ModifyPol(char PolID) { TPolArc * polarc; for (int i = 0; i < (int)PolArc.size(); i++) { if (PolID == PolArc[i]->PolID) { polarc = PolArc[i]; polarc->ArcID.push_back(islandinfo.AfterID); } } } //判断点是否在多边形中 bool CreateTopology::PtInRegion(Point* point, vector<Point*> pllPoint) { int wn = 0; // the winding number counter std::vector<Point *>::iterator it; // loop through all edges of the polygon for (it=pllPoint.begin(); it<pllPoint.end()-1; it++)// edge from V[i] to V[i+1] { if ((*(it))->Y <= point->Y) { // start Y <= pt->Y if ((*(it+1))->Y > point->Y) // an upward crossing if (IsLeft( *it, *(it+1), point) > 0) // P left of edge ++wn; // have a valid up intersect } else { // start Y > P.Y (no test needed) if ((*(it+1))->Y <= point->Y) // a downward crossing if (IsLeft( *it, *(it+1), point) < 0) // P right of edge --wn; // have a valid down intersect } } if (wn==0) return false; return true; } double CreateTopology::IsLeft(Point *P0, Point *P1, Point *P2 ) { return ( (P1->X - P0->X) * (P2->Y - P0->Y) - (P2->X - P0->X) * (P1->Y - P0->Y) ); } void CreateTopology::BuildArcPol(vector<Arc*> arcs, vector<Polygon*> Polygons) { vector<Arc*>::iterator iterA; for (iterA = arcs.begin(); iterA != arcs.end(); iterA++) { TArcPol* tarcpol = new TArcPol; tarcpol->ArcID = (*iterA)->ID; vector<Point*>::iterator iterB; vector<Point*>::iterator iterE; iterB = (*iterA)->Points.begin(); iterE = (*iterA)->Points.end()-1; tarcpol->StartID = (*iterB)->ID; tarcpol->EndID = (*iterE)->ID; vector<Polygon*>::iterator iterP; bool right = false, left = false; //判断是否为岛（即单弧段）,目前只能可以判断一个岛，没有考虑多个岛的情况 if (strcmp((*iterA)->ID.c_str(),islandinfo.BeforeID.c_str()) ==0) { tarcpol->RightP = islandinfo.InPolID; tarcpol->LeftP = islandinfo.OutPolID; right = true; left = true; } else { for ( iterP = Polygons.begin(); iterP != Polygons.end(); iterP++) { for (int i = 0; i < (int)(*iterP)->ArcPts.size(); i++) { ArcDir* arcpoint = (*iterP)->ArcPts[i]; Arc * arc = arcpoint->arcs; if (strcmp((*iterA)->ID.c_str(), arc->ID.c_str()) == 0) { if (arcpoint->Direction == 1) { tarcpol->RightP = (*iterP)->ID; right = true; } else if (arcpoint->Direction == -1) { tarcpol->LeftP = (*iterP)->ID; left = true; } } } } } if (right == true && left == false) { tarcpol->LeftP = 'Q'; } if (right == false && left == true) { tarcpol->LeftP = 'Q'; } ArcPol.push_back(tarcpol); } } void CreateTopology::PrintTopTables(void) { cout << "/n/n" << "点的坐标文件" << endl; cout <<"点号"<< " "<< "坐标" << " " << "点号"<< " "<< "坐标"<< endl; for (int i = 0; i < (int)Points.size(); i++) { cout << " " << this->Points[i]->ID << " " << "(" << this->Points[i]->X << "," << this->Points[i]->Y << ")" << " "; if (i < (int)Points.size() -1) { i++; cout << " " << this->Points[i]->ID << " " << "(" << this->Points[i]->X << "," << this->Points[i]->Y << ")" << endl; } } cout << "/n/n" << "弧段-点文件" << endl; cout << "多边形ID" << " " << "弧段号"<< endl; for (int i = 0; i < (int)Arcpoints.size(); i++) { cout << " " << Arcpoints[i]->ArcID.c_str() << " " ; for (int j = 0; j < (int)Arcpoints[i]->PointID.size(); j++) { cout<< Arcpoints[i]->PointID[j] << " "; } cout << endl; } cout << endl << "多边形拓扑文件" << endl; cout << "弧段ID" << " " << "点号"<< endl; for (int i = 0; i < (int)PolArc.size(); i++) { cout << " " << PolArc[i]->PolID << " "; for (int j = 0; j < (int)PolArc[i]->ArcID.size(); j++) { cout << PolArc[i]->ArcID[j].c_str()<< " "; } cout <<endl; } cout << endl << "弧段拓扑文件" << endl; cout << "弧段ID"<<" "<< "起始点"<<" " << "终结点" <<" " << "左多边形"<<" "<<"右多边形" << endl; for (int i = 0; i < (int)ArcPol.size(); i++) { cout << " "<<ArcPol[i]->ArcID.c_str()<< setw(9) << right << ArcPol[i]->StartID << setw(8) << right << ArcPol[i]->EndID << setw(8) << right<< ArcPol[i]->LeftP <<setw(10) << right<< ArcPol[i]->RightP <<endl; } }