exampleConstImageFunctorHolder.cpp

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// Inclusions
#include "DGtal/base/Common.h"
#include "DGtal/helpers/StdDefs.h"
#include "DGtal/io/boards/Board2D.h"
 
#include <cmath>
#include <DGtal/io/colormaps/HueShadeColorMap.h>

#include "DGtal/images/ConstImageFunctorHolder.h"
 
int main()
{
  using namespace DGtal::Z2i;
 
  DGtal::Board2D aBoard;

  using Value = double; // value type  of the image
  using HueShadeDouble = DGtal::HueShadeColorMap<Value>;  // a simple HueShadeColorMap varying on 'double' values
 
  // Image from a unary lambda
  const Domain domain1(Point(1,1), Point(16,16));
 
  auto image1 = DGtal::functors::holdConstImageFunctor(
      domain1,
      [] (Point const& pt) { return 25 * ( std::cos( (pt - Point(4,4)).norm() ) + 1 ); }
  );
 
  aBoard.clear();
  DGtal::Display2DFactory::drawImage<HueShadeDouble>(aBoard, image1, 0, 225);
  aBoard.saveSVG("ConstImageFunctorHolder_example1.svg");
 
  // Image from a binary lambda
  const Domain domain2(Point(-1,1), Point(18,18));
 
  auto image2 = DGtal::functors::holdConstImageFunctor(
      domain2,
      [] (Point const& pt, Domain const& d) { // we could also capture the domain
        return 2 * std::min( ( pt - d.lowerBound() ).norm(), ( pt - d.upperBound() ).norm() );
      }
  );
 
  aBoard.clear();
  DGtal::Display2DFactory::drawImage<HueShadeDouble>(aBoard, image2, 0, 225);
  aBoard.saveSVG("ConstImageFunctorHolder_example2.svg");
 
  // Image that depends on other images
  auto image3 = DGtal::functors::holdConstImageFunctor(
      domain1,
      [&image1, &image2] (Point const& pt) { return image1(pt) + image2(pt); }
  );
 
  aBoard.clear();
  DGtal::Display2DFactory::drawImage<HueShadeDouble>(aBoard, image3, 0, 225);
  aBoard.saveSVG("ConstImageFunctorHolder_example3.svg");
  return 0;
}