Chris@16: /*
Chris@16:   Copyright 2008 Intel Corporation
Chris@16: 
Chris@16:   Use, modification and distribution are subject to the Boost Software License,
Chris@16:   Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:   http://www.boost.org/LICENSE_1_0.txt).
Chris@16: */
Chris@16: #ifndef BOOST_POLYGON_PROPERTY_MERGE_HPP
Chris@16: #define BOOST_POLYGON_PROPERTY_MERGE_HPP
Chris@16: namespace boost { namespace polygon{
Chris@16: 
Chris@16: template <typename coordinate_type>
Chris@16: class property_merge_point {
Chris@16: private:
Chris@16:   coordinate_type x_, y_;
Chris@16: public:
Chris@16:   inline property_merge_point() : x_(), y_() {}
Chris@16:   inline property_merge_point(coordinate_type x, coordinate_type y) : x_(x), y_(y) {}
Chris@16:   //use builtin assign and copy
Chris@16:   inline bool operator==(const property_merge_point& that) const { return x_ == that.x_ && y_ == that.y_; }
Chris@16:   inline bool operator!=(const property_merge_point& that) const { return !((*this) == that); }
Chris@16:   inline bool operator<(const property_merge_point& that) const {
Chris@16:     if(x_ < that.x_) return true;
Chris@16:     if(x_ > that.x_) return false;
Chris@16:     return y_ < that.y_;
Chris@16:   }
Chris@16:   inline coordinate_type x() const { return x_; }
Chris@16:   inline coordinate_type y() const { return y_; }
Chris@16:   inline void x(coordinate_type value) { x_ = value; }
Chris@16:   inline void y(coordinate_type value) { y_ = value; }
Chris@16: };
Chris@16: 
Chris@16: template <typename coordinate_type>
Chris@16: class property_merge_interval {
Chris@16: private:
Chris@16:   coordinate_type low_, high_;
Chris@16: public:
Chris@16:   inline property_merge_interval() : low_(), high_() {}
Chris@16:   inline property_merge_interval(coordinate_type low, coordinate_type high) : low_(low), high_(high) {}
Chris@16:   //use builtin assign and copy
Chris@16:   inline bool operator==(const property_merge_interval& that) const { return low_ == that.low_ && high_ == that.high_; }
Chris@16:   inline bool operator!=(const property_merge_interval& that) const { return !((*this) == that); }
Chris@16:   inline bool operator<(const property_merge_interval& that) const {
Chris@16:     if(low_ < that.low_) return true;
Chris@16:     if(low_ > that.low_) return false;
Chris@16:     return high_ < that.high_;
Chris@16:   }
Chris@16:   inline coordinate_type low() const { return low_; }
Chris@16:   inline coordinate_type high() const { return high_; }
Chris@16:   inline void low(coordinate_type value) { low_ = value; }
Chris@16:   inline void high(coordinate_type value) { high_ = value; }
Chris@16: };
Chris@16: 
Chris@16: template <typename coordinate_type, typename property_type, typename polygon_set_type, typename keytype = std::set<property_type> >
Chris@16: class merge_scanline {
Chris@16: public:
Chris@16:   //definitions
Chris@16: 
Chris@16:   typedef keytype property_set;
Chris@16:   typedef std::vector<std::pair<property_type, int> > property_map;
Chris@16:   typedef std::pair<property_merge_point<coordinate_type>, std::pair<property_type, int> > vertex_property;
Chris@16:   typedef std::pair<property_merge_point<coordinate_type>, property_map> vertex_data;
Chris@16:   typedef std::vector<vertex_property> property_merge_data;
Chris@16:   //typedef std::map<property_set, polygon_set_type> Result;
Chris@16:   typedef std::map<coordinate_type, property_map> scanline_type;
Chris@16:   typedef typename scanline_type::iterator scanline_iterator;
Chris@16:   typedef std::pair<property_merge_interval<coordinate_type>, std::pair<property_set, property_set> > edge_property;
Chris@16:   typedef std::vector<edge_property> edge_property_vector;
Chris@16: 
Chris@16:   //static public member functions
Chris@16: 
Chris@16:   template <typename iT, typename orientation_2d_type>
Chris@16:   static inline void
Chris@16:   populate_property_merge_data(property_merge_data& pmd, iT input_begin, iT input_end,
Chris@16:                                const property_type& property, orientation_2d_type orient) {
Chris@16:     for( ; input_begin != input_end; ++input_begin) {
Chris@16:       std::pair<property_merge_point<coordinate_type>, std::pair<property_type, int> > element;
Chris@16:       if(orient == HORIZONTAL)
Chris@16:         element.first = property_merge_point<coordinate_type>((*input_begin).second.first, (*input_begin).first);
Chris@16:       else
Chris@16:         element.first = property_merge_point<coordinate_type>((*input_begin).first, (*input_begin).second.first);
Chris@16:       element.second.first = property;
Chris@16:       element.second.second = (*input_begin).second.second;
Chris@16:       pmd.push_back(element);
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   //public member functions
Chris@16: 
Chris@16:   merge_scanline() : output(), scanline(), currentVertex(), tmpVector(), previousY(), countFromBelow(), scanlinePosition() {}
Chris@16:   merge_scanline(const merge_scanline& that) :
Chris@16:     output(that.output),
Chris@16:     scanline(that.scanline),
Chris@16:     currentVertex(that.currentVertex),
Chris@16:     tmpVector(that.tmpVector),
Chris@16:     previousY(that.previousY),
Chris@16:     countFromBelow(that.countFromBelow),
Chris@16:     scanlinePosition(that.scanlinePosition)
Chris@16:   {}
Chris@16:   merge_scanline& operator=(const merge_scanline& that) {
Chris@16:     output = that.output;
Chris@16:     scanline = that.scanline;
Chris@16:     currentVertex = that.currentVertex;
Chris@16:     tmpVector = that.tmpVector;
Chris@16:     previousY = that.previousY;
Chris@16:     countFromBelow = that.countFromBelow;
Chris@16:     scanlinePosition = that.scanlinePosition;
Chris@16:     return *this;
Chris@16:   }
Chris@16: 
Chris@16:   template <typename result_type>
Chris@16:   inline void perform_merge(result_type& result, property_merge_data& data) {
Chris@16:     if(data.empty()) return;
Chris@16:     //sort
Chris@16:     polygon_sort(data.begin(), data.end(), less_vertex_data<vertex_property>());
Chris@16:     //scanline
Chris@16:     bool firstIteration = true;
Chris@16:     scanlinePosition = scanline.end();
Chris@16:     for(std::size_t i = 0; i < data.size(); ++i) {
Chris@16:       if(firstIteration) {
Chris@16:         mergeProperty(currentVertex.second, data[i].second);
Chris@16:         currentVertex.first = data[i].first;
Chris@16:         firstIteration = false;
Chris@16:       } else {
Chris@16:         if(data[i].first != currentVertex.first) {
Chris@16:           if(data[i].first.x() != currentVertex.first.x()) {
Chris@16:             processVertex(output);
Chris@16:             //std::cout << scanline.size() << " ";
Chris@16:             countFromBelow.clear(); //should already be clear
Chris@16:             writeOutput(currentVertex.first.x(), result, output);
Chris@16:             currentVertex.second.clear();
Chris@16:             mergeProperty(currentVertex.second, data[i].second);
Chris@16:             currentVertex.first = data[i].first;
Chris@16:             //std::cout << assertRedundant(scanline) << "/" << scanline.size() << " ";
Chris@16:           } else {
Chris@16:             processVertex(output);
Chris@16:             currentVertex.second.clear();
Chris@16:             mergeProperty(currentVertex.second, data[i].second);
Chris@16:             currentVertex.first = data[i].first;
Chris@16:           }
Chris@16:         } else {
Chris@16:           mergeProperty(currentVertex.second, data[i].second);
Chris@16:         }
Chris@16:       }
Chris@16:     }
Chris@16:     processVertex(output);
Chris@16:     writeOutput(currentVertex.first.x(), result, output);
Chris@16:     //std::cout << assertRedundant(scanline) << "/" << scanline.size() << "\n";
Chris@16:     //std::cout << scanline.size() << "\n";
Chris@16:   }
Chris@16: 
Chris@16: private:
Chris@16:   //private supporting types
Chris@16: 
Chris@16:   template <class T>
Chris@16:   class less_vertex_data {
Chris@16:   public:
Chris@16:     less_vertex_data() {}
Chris@16:     bool operator()(const T& lvalue, const T& rvalue) const {
Chris@16:       if(lvalue.first.x() < rvalue.first.x()) return true;
Chris@16:       if(lvalue.first.x() > rvalue.first.x()) return false;
Chris@16:       if(lvalue.first.y() < rvalue.first.y()) return true;
Chris@16:       return false;
Chris@16:     }
Chris@16:   };
Chris@16: 
Chris@16:   template <typename T>
Chris@16:   struct lessPropertyCount {
Chris@16:     lessPropertyCount() {}
Chris@16:     bool operator()(const T& a, const T& b) {
Chris@16:       return a.first < b.first;
Chris@16:     }
Chris@16:   };
Chris@16: 
Chris@16:   //private static member functions
Chris@16: 
Chris@16:   static inline void mergeProperty(property_map& lvalue, std::pair<property_type, int>& rvalue) {
Chris@16:     typename property_map::iterator itr = std::lower_bound(lvalue.begin(), lvalue.end(), rvalue,
Chris@16:                                                           lessPropertyCount<std::pair<property_type, int> >());
Chris@16:     if(itr == lvalue.end() ||
Chris@16:        (*itr).first != rvalue.first) {
Chris@16:       lvalue.insert(itr, rvalue);
Chris@16:     } else {
Chris@16:       (*itr).second += rvalue.second;
Chris@16:       if((*itr).second == 0)
Chris@16:         lvalue.erase(itr);
Chris@16:     }
Chris@16: //     if(assertSorted(lvalue)) {
Chris@16: //       std::cout << "in mergeProperty\n";
Chris@16: //       exit(0);
Chris@16: //     }
Chris@16:   }
Chris@16: 
Chris@16: //   static inline bool assertSorted(property_map& pset) {
Chris@16: //     bool result = false;
Chris@16: //     for(std::size_t i = 1; i < pset.size(); ++i) {
Chris@16: //       if(pset[i] < pset[i-1]) {
Chris@16: //         std::cout << "Out of Order Error ";
Chris@16: //         result = true;
Chris@16: //       }
Chris@16: //       if(pset[i].first == pset[i-1].first) {
Chris@16: //         std::cout << "Duplicate Property Error ";
Chris@16: //         result = true;
Chris@16: //       }
Chris@16: //       if(pset[0].second == 0 || pset[1].second == 0) {
Chris@16: //         std::cout << "Empty Property Error ";
Chris@16: //         result = true;
Chris@16: //       }
Chris@16: //     }
Chris@16: //     return result;
Chris@16: //   }
Chris@16: 
Chris@16:   static inline void setProperty(property_set& pset, property_map& pmap) {
Chris@16:     for(typename property_map::iterator itr = pmap.begin(); itr != pmap.end(); ++itr) {
Chris@16:       if((*itr).second > 0) {
Chris@16:         pset.insert(pset.end(), (*itr).first);
Chris@16:       }
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   //private data members
Chris@16: 
Chris@16:   edge_property_vector output;
Chris@16:   scanline_type scanline;
Chris@16:   vertex_data currentVertex;
Chris@16:   property_map tmpVector;
Chris@16:   coordinate_type previousY;
Chris@16:   property_map countFromBelow;
Chris@16:   scanline_iterator scanlinePosition;
Chris@16: 
Chris@16:   //private member functions
Chris@16: 
Chris@16:   inline void mergeCount(property_map& lvalue, property_map& rvalue) {
Chris@16:     typename property_map::iterator litr = lvalue.begin();
Chris@16:     typename property_map::iterator ritr = rvalue.begin();
Chris@16:     tmpVector.clear();
Chris@16:     while(litr != lvalue.end() && ritr != rvalue.end()) {
Chris@16:       if((*litr).first <= (*ritr).first) {
Chris@16:         if(!tmpVector.empty() &&
Chris@16:            (*litr).first == tmpVector.back().first) {
Chris@16:           tmpVector.back().second += (*litr).second;
Chris@16:         } else {
Chris@16:           tmpVector.push_back(*litr);
Chris@16:         }
Chris@16:         ++litr;
Chris@16:       } else if((*ritr).first <= (*litr).first) {
Chris@16:         if(!tmpVector.empty() &&
Chris@16:            (*ritr).first == tmpVector.back().first) {
Chris@16:           tmpVector.back().second += (*ritr).second;
Chris@16:         } else {
Chris@16:           tmpVector.push_back(*ritr);
Chris@16:         }
Chris@16:         ++ritr;
Chris@16:       }
Chris@16:     }
Chris@16:     while(litr != lvalue.end()) {
Chris@16:       if(!tmpVector.empty() &&
Chris@16:          (*litr).first == tmpVector.back().first) {
Chris@16:         tmpVector.back().second += (*litr).second;
Chris@16:       } else {
Chris@16:         tmpVector.push_back(*litr);
Chris@16:       }
Chris@16:       ++litr;
Chris@16:     }
Chris@16:     while(ritr != rvalue.end()) {
Chris@16:       if(!tmpVector.empty() &&
Chris@16:          (*ritr).first == tmpVector.back().first) {
Chris@16:         tmpVector.back().second += (*ritr).second;
Chris@16:       } else {
Chris@16:         tmpVector.push_back(*ritr);
Chris@16:       }
Chris@16:       ++ritr;
Chris@16:     }
Chris@16:     lvalue.clear();
Chris@16:     for(std::size_t i = 0; i < tmpVector.size(); ++i) {
Chris@16:       if(tmpVector[i].second != 0) {
Chris@16:         lvalue.push_back(tmpVector[i]);
Chris@16:       }
Chris@16:     }
Chris@16: //     if(assertSorted(lvalue)) {
Chris@16: //       std::cout << "in mergeCount\n";
Chris@16: //       exit(0);
Chris@16: //     }
Chris@16:   }
Chris@16: 
Chris@16:   inline void processVertex(edge_property_vector& output) {
Chris@16:     if(!countFromBelow.empty()) {
Chris@16:       //we are processing an interval of change in scanline state between
Chris@16:       //previous vertex position and current vertex position where
Chris@16:       //count from below represents the change on the interval
Chris@16:       //foreach scanline element from previous to current we
Chris@16:       //write the interval on the scanline that is changing
Chris@16:       //the old value and the new value to output
Chris@16:       property_merge_interval<coordinate_type> currentInterval(previousY, currentVertex.first.y());
Chris@16:       coordinate_type currentY = currentInterval.low();
Chris@16:       if(scanlinePosition == scanline.end() ||
Chris@16:          (*scanlinePosition).first != previousY) {
Chris@16:         scanlinePosition = scanline.lower_bound(previousY);
Chris@16:       }
Chris@16:       scanline_iterator previousScanlinePosition = scanlinePosition;
Chris@16:       ++scanlinePosition;
Chris@16:       while(scanlinePosition != scanline.end()) {
Chris@16:         coordinate_type elementY = (*scanlinePosition).first;
Chris@16:         if(elementY <= currentInterval.high()) {
Chris@16:           property_map& countOnLeft = (*previousScanlinePosition).second;
Chris@16:           edge_property element;
Chris@16:           output.push_back(element);
Chris@16:           output.back().first = property_merge_interval<coordinate_type>((*previousScanlinePosition).first, elementY);
Chris@16:           setProperty(output.back().second.first, countOnLeft);
Chris@16:           mergeCount(countOnLeft, countFromBelow);
Chris@16:           setProperty(output.back().second.second, countOnLeft);
Chris@16:           if(output.back().second.first == output.back().second.second) {
Chris@16:             output.pop_back(); //it was an internal vertical edge, not to be output
Chris@16:           }
Chris@16:           else if(output.size() > 1) {
Chris@16:             edge_property& secondToLast = output[output.size()-2];
Chris@16:             if(secondToLast.first.high() == output.back().first.low() &&
Chris@16:                secondToLast.second.first == output.back().second.first &&
Chris@16:                secondToLast.second.second == output.back().second.second) {
Chris@16:               //merge output onto previous output because properties are
Chris@16:               //identical on both sides implying an internal horizontal edge
Chris@16:               secondToLast.first.high(output.back().first.high());
Chris@16:               output.pop_back();
Chris@16:             }
Chris@16:           }
Chris@16:           if(previousScanlinePosition == scanline.begin()) {
Chris@16:             if(countOnLeft.empty()) {
Chris@16:               scanline.erase(previousScanlinePosition);
Chris@16:             }
Chris@16:           } else {
Chris@16:             scanline_iterator tmpitr = previousScanlinePosition;
Chris@16:             --tmpitr;
Chris@16:             if((*tmpitr).second == (*previousScanlinePosition).second)
Chris@16:               scanline.erase(previousScanlinePosition);
Chris@16:           }
Chris@16: 
Chris@16:         } else if(currentY < currentInterval.high()){
Chris@16:           //elementY > currentInterval.high()
Chris@16:           //split the interval between previous and current scanline elements
Chris@16:           std::pair<coordinate_type, property_map> elementScan;
Chris@16:           elementScan.first = currentInterval.high();
Chris@16:           elementScan.second = (*previousScanlinePosition).second;
Chris@16:           scanlinePosition = scanline.insert(scanlinePosition, elementScan);
Chris@16:           continue;
Chris@16:         } else {
Chris@16:           break;
Chris@16:         }
Chris@16:         previousScanlinePosition = scanlinePosition;
Chris@16:         currentY = previousY = elementY;
Chris@16:         ++scanlinePosition;
Chris@16:         if(scanlinePosition == scanline.end() &&
Chris@16:            currentY < currentInterval.high()) {
Chris@16:           //insert a new element for top of range
Chris@16:           std::pair<coordinate_type, property_map> elementScan;
Chris@16:           elementScan.first = currentInterval.high();
Chris@16:           scanlinePosition = scanline.insert(scanline.end(), elementScan);
Chris@16:         }
Chris@16:       }
Chris@16:       if(scanlinePosition == scanline.end() &&
Chris@16:          currentY < currentInterval.high()) {
Chris@16:         //handle case where we iterated to end of the scanline
Chris@16:         //we need to insert an element into the scanline at currentY
Chris@16:         //with property value coming from below
Chris@16:         //and another one at currentInterval.high() with empty property value
Chris@16:         mergeCount(scanline[currentY], countFromBelow);
Chris@16:         std::pair<coordinate_type, property_map> elementScan;
Chris@16:         elementScan.first = currentInterval.high();
Chris@16:         scanline.insert(scanline.end(), elementScan);
Chris@16: 
Chris@16:         edge_property element;
Chris@16:         output.push_back(element);
Chris@16:         output.back().first = property_merge_interval<coordinate_type>(currentY, currentInterval.high());
Chris@16:         setProperty(output.back().second.second, countFromBelow);
Chris@16:         mergeCount(countFromBelow, currentVertex.second);
Chris@16:       } else {
Chris@16:         mergeCount(countFromBelow, currentVertex.second);
Chris@16:         if(countFromBelow.empty()) {
Chris@16:           if(previousScanlinePosition == scanline.begin()) {
Chris@16:             if((*previousScanlinePosition).second.empty()) {
Chris@16:               scanline.erase(previousScanlinePosition);
Chris@16:               //previousScanlinePosition = scanline.end();
Chris@16:               //std::cout << "ERASE_A ";
Chris@16:             }
Chris@16:           } else {
Chris@16:             scanline_iterator tmpitr = previousScanlinePosition;
Chris@16:             --tmpitr;
Chris@16:             if((*tmpitr).second == (*previousScanlinePosition).second) {
Chris@16:               scanline.erase(previousScanlinePosition);
Chris@16:               //previousScanlinePosition = scanline.end();
Chris@16:               //std::cout << "ERASE_B ";
Chris@16:             }
Chris@16:           }
Chris@16:         }
Chris@16:       }
Chris@16:     } else {
Chris@16:       //count from below is empty, we are starting a new interval of change
Chris@16:       countFromBelow = currentVertex.second;
Chris@16:       scanlinePosition = scanline.lower_bound(currentVertex.first.y());
Chris@16:       if(scanlinePosition != scanline.end()) {
Chris@16:         if((*scanlinePosition).first != currentVertex.first.y()) {
Chris@16:           if(scanlinePosition != scanline.begin()) {
Chris@16:             //decrement to get the lower position of the first interval this vertex intersects
Chris@16:             --scanlinePosition;
Chris@16:             //insert a new element into the scanline for the incoming vertex
Chris@16:             property_map& countOnLeft = (*scanlinePosition).second;
Chris@16:             std::pair<coordinate_type, property_map> element(currentVertex.first.y(), countOnLeft);
Chris@16:             scanlinePosition = scanline.insert(scanlinePosition, element);
Chris@16:           } else {
Chris@16:             property_map countOnLeft;
Chris@16:             std::pair<coordinate_type, property_map> element(currentVertex.first.y(), countOnLeft);
Chris@16:             scanlinePosition = scanline.insert(scanlinePosition, element);
Chris@16:           }
Chris@16:         }
Chris@16:       } else {
Chris@16:         property_map countOnLeft;
Chris@16:         std::pair<coordinate_type, property_map> element(currentVertex.first.y(), countOnLeft);
Chris@16:         scanlinePosition = scanline.insert(scanlinePosition, element);
Chris@16:       }
Chris@16:     }
Chris@16:     previousY = currentVertex.first.y();
Chris@16:   }
Chris@16: 
Chris@16:   template <typename T>
Chris@16:   inline int assertRedundant(T& t) {
Chris@16:     if(t.empty()) return 0;
Chris@16:     int count = 0;
Chris@16:     typename T::iterator itr = t.begin();
Chris@16:     if((*itr).second.empty())
Chris@16:       ++count;
Chris@16:     typename T::iterator itr2 = itr;
Chris@16:     ++itr2;
Chris@16:     while(itr2 != t.end()) {
Chris@16:       if((*itr).second == (*itr2).second)
Chris@16:         ++count;
Chris@16:       itr = itr2;
Chris@16:       ++itr2;
Chris@16:     }
Chris@16:     return count;
Chris@16:   }
Chris@16: 
Chris@16:   template <typename T>
Chris@16:   inline void performExtract(T& result, property_merge_data& data) {
Chris@16:     if(data.empty()) return;
Chris@16:     //sort
Chris@16:     polygon_sort(data.begin(), data.end(), less_vertex_data<vertex_property>());
Chris@16: 
Chris@16:     //scanline
Chris@16:     bool firstIteration = true;
Chris@16:     scanlinePosition = scanline.end();
Chris@16:     for(std::size_t i = 0; i < data.size(); ++i) {
Chris@16:       if(firstIteration) {
Chris@16:         mergeProperty(currentVertex.second, data[i].second);
Chris@16:         currentVertex.first = data[i].first;
Chris@16:         firstIteration = false;
Chris@16:       } else {
Chris@16:         if(data[i].first != currentVertex.first) {
Chris@16:           if(data[i].first.x() != currentVertex.first.x()) {
Chris@16:             processVertex(output);
Chris@16:             //std::cout << scanline.size() << " ";
Chris@16:             countFromBelow.clear(); //should already be clear
Chris@16:             writeGraph(currentVertex.first.x(), result, output, scanline);
Chris@16:             currentVertex.second.clear();
Chris@16:             mergeProperty(currentVertex.second, data[i].second);
Chris@16:             currentVertex.first = data[i].first;
Chris@16:           } else {
Chris@16:             processVertex(output);
Chris@16:             currentVertex.second.clear();
Chris@16:             mergeProperty(currentVertex.second, data[i].second);
Chris@16:             currentVertex.first = data[i].first;
Chris@16:           }
Chris@16:         } else {
Chris@16:           mergeProperty(currentVertex.second, data[i].second);
Chris@16:         }
Chris@16:       }
Chris@16:     }
Chris@16:     processVertex(output);
Chris@16:     writeGraph(currentVertex.first.x(), result, output, scanline);
Chris@16:     //std::cout << scanline.size() << "\n";
Chris@16:   }
Chris@16: 
Chris@16:   template <typename T>
Chris@16:   inline void insertEdges(T& graph, property_set& p1, property_set& p2) {
Chris@16:     for(typename property_set::iterator itr = p1.begin(); itr != p1.end(); ++itr) {
Chris@16:       for(typename property_set::iterator itr2 = p2.begin(); itr2 != p2.end(); ++itr2) {
Chris@16:         if(*itr != *itr2) {
Chris@16:           graph[*itr].insert(*itr2);
Chris@16:           graph[*itr2].insert(*itr);
Chris@16:         }
Chris@16:       }
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   template <typename T>
Chris@16:   inline void propertySetAbove(coordinate_type y, property_set& ps, T& scanline) {
Chris@16:     ps.clear();
Chris@16:     typename T::iterator itr = scanline.find(y);
Chris@16:     if(itr != scanline.end())
Chris@16:       setProperty(ps, (*itr).second);
Chris@16:   }
Chris@16: 
Chris@16:   template <typename T>
Chris@16:   inline void propertySetBelow(coordinate_type y, property_set& ps, T& scanline) {
Chris@16:     ps.clear();
Chris@16:     typename T::iterator itr = scanline.find(y);
Chris@16:     if(itr != scanline.begin()) {
Chris@16:       --itr;
Chris@16:       setProperty(ps, (*itr).second);
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   template <typename T, typename T2>
Chris@16:   inline void writeGraph(coordinate_type x, T& graph, edge_property_vector& output, T2& scanline) {
Chris@16:     if(output.empty()) return;
Chris@16:     edge_property* previousEdgeP = &(output[0]);
Chris@16:     bool firstIteration = true;
Chris@16:     property_set ps;
Chris@16:     for(std::size_t i = 0; i < output.size(); ++i) {
Chris@16:       edge_property& previousEdge = *previousEdgeP;
Chris@16:       edge_property& edge = output[i];
Chris@16:       if(previousEdge.first.high() == edge.first.low()) {
Chris@16:         //horizontal edge
Chris@16:         insertEdges(graph, edge.second.first, previousEdge.second.first);
Chris@16:         //corner 1
Chris@16:         insertEdges(graph, edge.second.first, previousEdge.second.second);
Chris@16:         //other horizontal edge
Chris@16:         insertEdges(graph, edge.second.second, previousEdge.second.second);
Chris@16:         //corner 2
Chris@16:         insertEdges(graph, edge.second.second, previousEdge.second.first);
Chris@16:       } else {
Chris@16:         if(!firstIteration){
Chris@16:           //look up regions above previous edge
Chris@16:           propertySetAbove(previousEdge.first.high(), ps, scanline);
Chris@16:           insertEdges(graph, ps, previousEdge.second.first);
Chris@16:           insertEdges(graph, ps, previousEdge.second.second);
Chris@16:         }
Chris@16:         //look up regions below current edge in the scanline
Chris@16:         propertySetBelow(edge.first.high(), ps, scanline);
Chris@16:         insertEdges(graph, ps, edge.second.first);
Chris@16:         insertEdges(graph, ps, edge.second.second);
Chris@16:       }
Chris@16:       firstIteration = false;
Chris@16:       //vertical edge
Chris@16:       insertEdges(graph, edge.second.second, edge.second.first);
Chris@16:       //shared region to left
Chris@16:       insertEdges(graph, edge.second.second, edge.second.second);
Chris@16:       //shared region to right
Chris@16:       insertEdges(graph, edge.second.first, edge.second.first);
Chris@16:       previousEdgeP = &(output[i]);
Chris@16:     }
Chris@16:     edge_property& previousEdge = *previousEdgeP;
Chris@16:     propertySetAbove(previousEdge.first.high(), ps, scanline);
Chris@16:     insertEdges(graph, ps, previousEdge.second.first);
Chris@16:     insertEdges(graph, ps, previousEdge.second.second);
Chris@16:     output.clear();
Chris@16:   }
Chris@16: 
Chris@16:   template <typename Result>
Chris@16:   inline void writeOutput(coordinate_type x, Result& result, edge_property_vector& output) {
Chris@16:     for(std::size_t i = 0; i < output.size(); ++i) {
Chris@16:       edge_property& edge = output[i];
Chris@16:       //edge.second.first is the property set on the left of the edge
Chris@16:       if(!edge.second.first.empty()) {
Chris@16:         typename Result::iterator itr = result.find(edge.second.first);
Chris@16:         if(itr == result.end()) {
Chris@16:           std::pair<property_set, polygon_set_type> element(edge.second.first, polygon_set_type(VERTICAL));
Chris@16:           itr = result.insert(result.end(), element);
Chris@16:         }
Chris@16:         std::pair<interval_data<coordinate_type>, int> element2(interval_data<coordinate_type>(edge.first.low(), edge.first.high()), -1); //right edge of figure
Chris@16:         (*itr).second.insert(x, element2);
Chris@16:       }
Chris@16:       if(!edge.second.second.empty()) {
Chris@16:         //edge.second.second is the property set on the right of the edge
Chris@16:         typename Result::iterator itr = result.find(edge.second.second);
Chris@16:         if(itr == result.end()) {
Chris@16:           std::pair<property_set, polygon_set_type> element(edge.second.second, polygon_set_type(VERTICAL));
Chris@16:           itr = result.insert(result.end(), element);
Chris@16:         }
Chris@16:         std::pair<interval_data<coordinate_type>, int> element3(interval_data<coordinate_type>(edge.first.low(), edge.first.high()), 1); //left edge of figure
Chris@16:         (*itr).second.insert(x, element3);
Chris@16:       }
Chris@16:     }
Chris@16:     output.clear();
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: }
Chris@16: }
Chris@16: #endif