/* public */
void
PolygonizeGraph::deleteDangles(std::vector<const LineString*>& dangleLines)
{
std::vector<Node*> nodeStack;
findNodesOfDegree(1, nodeStack);
std::set<const LineString*> uniqueDangles;
while (!nodeStack.empty()) {
Node *node=nodeStack.back();
nodeStack.pop_back();
deleteAllEdges(node);
std::vector<DirectedEdge*> &nodeOutEdges=node->getOutEdges()->getEdges();
for(unsigned int j=0; j<nodeOutEdges.size(); ++j)
{
PolygonizeDirectedEdge *de=(PolygonizeDirectedEdge*)nodeOutEdges[j];
// delete this edge and its sym
de->setMarked(true);
PolygonizeDirectedEdge *sym=(PolygonizeDirectedEdge*) de->getSym();
if (sym != NULL)
sym->setMarked(true);
// save the line as a dangle
PolygonizeEdge *e=(PolygonizeEdge*) de->getEdge();
const LineString* ls = e->getLine();
if ( uniqueDangles.insert(ls).second )
dangleLines.push_back(ls);
Node *toNode=de->getToNode();
// add the toNode to the list to be processed,
// if it is now a dangle
if (getDegreeNonDeleted(toNode)==1)
nodeStack.push_back(toNode);
}
}
}
/**
* Marks all edges from the graph which are "dangles".
* Dangles are which are incident on a node with degree 1.
* This process is recursive, since removing a dangling edge
* may result in another edge becoming a dangle.
* In order to handle large recursion depths efficiently,
* an explicit recursion stack is used
*
* @return a List containing the LineStrings that formed dangles
*/
vector<const LineString*>*
PolygonizeGraph::deleteDangles()
{
vector<planarNode*> *nodesToRemove=findNodesOfDegree(1);
vector<const LineString*> *dangleLines=new vector<const LineString*>();
vector<planarNode*> nodeStack;
for(int i=0;i<(int)nodesToRemove->size();i++) {
nodeStack.push_back((*nodesToRemove)[i]);
}
delete nodesToRemove;
while (!nodeStack.empty()) {
planarNode *node=nodeStack[nodeStack.size()-1];
nodeStack.pop_back();
deleteAllEdges(node);
vector<planarDirectedEdge*> *nodeOutEdges=node->getOutEdges()->getEdges();
for(int j=0;j<(int)nodeOutEdges->size();j++) {
PolygonizeDirectedEdge *de=(PolygonizeDirectedEdge*) (*nodeOutEdges)[j];
// delete this edge and its sym
de->setMarked(true);
PolygonizeDirectedEdge *sym=(PolygonizeDirectedEdge*) de->getSym();
if (sym != NULL)
sym->setMarked(true);
// save the line as a dangle
PolygonizeEdge *e=(PolygonizeEdge*) de->getEdge();
dangleLines->push_back(e->getLine());
planarNode *toNode=de->getToNode();
// add the toNode to the list to be processed, if it is now a dangle
if (getDegreeNonDeleted(toNode)==1)
nodeStack.push_back(toNode);
}
}
return dangleLines;
}
/*public*/
vector<Node*>*
PlanarGraph::findNodesOfDegree(size_t degree)
{
vector<Node*> *nodesFound=new vector<Node*>();
findNodesOfDegree(degree, *nodesFound);
return nodesFound;
}