monoChain.h

/*
 * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
 * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
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 */
/*
*/

#ifndef _MONO_CHAIN_H
#define _MONO_CHAIN_H

#include "directedLine.h"
#include "partitionY.h"

class monoChain;

class monoChain{
  directedLine* chainHead;
  directedLine* chainTail;
  monoChain* next;
  monoChain* prev;
  monoChain* nextPolygon; //a list of polygons
  
  //cached informatin
  //bounding box
  Real minX, maxX, minY, maxY;
  Int isIncrease;
  
  //for efficiently comparing two chains

  directedLine* current;
  
public:
  monoChain(directedLine* cHead, directedLine* cTail);
  ~monoChain() {}
  
  inline  void setNext(monoChain* n) {next = n;}
  inline void setPrev(monoChain* p) {prev = p;}
  inline void setNextPolygon(monoChain* np) {nextPolygon = np;}
  inline monoChain* getNext() {return next;}
  inline monoChain* getPrev() {return prev;}
  inline directedLine* getHead() {return chainHead;}
  inline directedLine* getTail() {return chainTail;}
  
  inline void resetCurrent() { current = ((isIncrease==1)? chainHead:chainTail);}

  void deleteLoop();
  void deleteLoopList();

  //insert a new chain between prev and this
  void insert(monoChain* nc);

  Int numChainsSingleLoop();
  Int numChainsAllLoops();
  monoChain** toArrayAllLoops(Int& num_chains);
  Int toArraySingleLoop(monoChain** array, Int index);

  Int isKey;
  Real keyY; //the current horizotal line  
  Real chainIntersectHoriz(Real y); //updates current incrementally for efficiency
  directedLine* find(Real y);//find dline so that y intersects dline.

  void printOneChain();
  void printChainLoop();
  void printAllLoops();
    
};

monoChain* directedLineLoopToMonoChainLoop(directedLine* loop);
monoChain* directedLineLoopListToMonoChainLoopList(directedLine* list);
Int MC_sweepY(Int nVertices, monoChain** sortedVertices, sweepRange** ret_ranges);

void MC_findDiagonals(Int total_num_edges, monoChain** sortedVertices,
                   sweepRange** ranges, Int& num_diagonals, 
                   directedLine** diagonal_vertices);

directedLine* MC_partitionY(directedLine *polygons, sampledLine **retSampledLines);

#endif