topology/khalimskySpaceScanner.cpp

A simple example illustrating different way to scan a Khalimsky space. This program outputs these images:

See also

Moving within the cellular grid space

 
#include <iostream>
#include "DGtal/base/Common.h"
#include "DGtal/topology/KhalimskySpaceND.h"
#include "DGtal/helpers/StdDefs.h"
#include "DGtal/io/Color.h"
#include "DGtal/io/boards/Board2D.h"
 
 
using namespace std;
using namespace DGtal;
 
 
int main( int argc, char** argv )
{
  trace.beginBlock ( "Example KhalimskySpaceScanner" );
  trace.info() << "Args:";
  for ( int i = 0; i < argc; ++i )
    trace.info() << " " << argv[ i ];
  trace.info() << endl;
  
  
  Board2D boardScan1; // for 2D display
  Board2D boardScan2; // for 2D display
  
 
  Z2i::KSpace K;
  Z2i::Point plow(0,0);
  Z2i::Point pup(3,2);
  
  Z2i::Domain dom (plow, pup);
  boardScan1 << SetMode( dom.className(), "Paving" )
        << dom;
  boardScan2 << SetMode( dom.className(), "Paving" )
        << dom;
  
  K.init( dom.lowerBound(),dom.upperBound(), true );
  
 
  
 Z2i::KSpace::Cell q = K.uSpel(plow);
 Z2i::KSpace::Cell p = K.uSpel(plow);
 
  
 Z2i::Vector shift;
 Z2i::KSpace::Cell prec=p;
 bool first=true;
 // Simple way to scan Khalimsky space 
 do 
   {
     boardScan1 << p;
     if(first){
       first=false;
       prec=p;
       continue;
     }
     // Drawing the scan arrows
     boardScan1.setPenColor( Color( 30, 30, 200 ));
     shift =   K.uCoords(p)-K.uCoords(prec);  
      Display2DFactory::draw(boardScan1, shift, K.uCoords(prec));
     prec=p;     
   }
 while ( K.uNext( p, K.uFirst(p), K.uLast(p) ) ); 
 
 
 
 
 // Other way to scan Khalimsky space by controlling axis order
 Z2i::Vector shiftq;
 Z2i::KSpace::Cell precq = q;
 bool firstq = true;
 using KPS = Z2i::KPreSpace;
 for ( KPS::Cell qq = K.uGetMax(q, 0); K.uIsInside(qq, 0); qq = KPS::uGetDecr(qq, 0) )
   {
     for ( KPS::uSetKCoord( qq, K.uFirst( qq, 1 ), 1 ); K.uIsInside(qq, 1); qq = KPS::uGetIncr(qq, 1) )
       {
         q = K.uCell( qq );
         boardScan2 << q;
         if(firstq){
             firstq = false;
             precq = q;
             continue;
         }
         // Drawing the scan arrows
         shiftq = K.uCoords(q) - K.uCoords(precq);
         boardScan2.setPenColor( Color( 30, 30, 200 ));
         Display2DFactory::draw(boardScan2, shiftq, K.uCoords(precq));
         precq = q;
       }
   }
 
 boardScan1.saveSVG("khalimskySpaceScanner1.svg");
 boardScan1.saveFIG("khalimskySpaceScanner1.fig");
 
 boardScan2.saveSVG("khalimskySpaceScanner2.svg");
 boardScan2.saveFIG("khalimskySpaceScanner2.fig");
  
  return 0;
 
}
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