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MakeSubRects.h

Go to the documentation of this file.

#ifndef Impala_Core_Geometry_MakeSubRects_h
#define Impala_Core_Geometry_MakeSubRects_h

#include "Core/Geometry/RectangleSet.h"

namespace Impala
{
namespace Core
{
namespace Geometry
{

template <class BackInsertIterator>
inline void
MakeSubRects(BackInsertIterator bi, int imWidth, int imHeight,
             int borderWidth, int nrRegionsX, int nrRegionsY, double overlap=0.5)
{

    if(overlap < 0 || overlap >= 1)
    {
        std::cout << "MakeSubRects: overlap not between [0,1), overlap: "
                    << overlap << std::endl;
        exit(1);
    }

//    std::cout << "imWidth: " << imWidth << std::endl;
//    std::cout << "imHeight: " << imHeight << std::endl;

    imWidth -= 2*borderWidth;
    imHeight -= 2*borderWidth;

    int regionWidth =  imWidth/nrRegionsX;
    int regionHeight = imHeight/nrRegionsY;

//    std::cout << "regionWidth: " << regionWidth << std::endl;
//    std::cout << "regionHeight: " << regionHeight << std::endl;

    int regionXoffset = regionWidth/2;
    int regionYoffset = regionHeight/2;

    int incrementX = regionWidth*(1.0-overlap);
    int incrementY = regionHeight*(1.0-overlap);

//    std::cout << "incrementX: " << incrementX << std::endl;
//    std::cout << "incrementY: " << incrementY << std::endl;


    int maxRegionsX = ((imWidth-regionWidth) / incrementX ) +1;
    int maxRegionsY = ((imHeight-regionHeight) / incrementY ) +1;

//    std::cout << "maxRegionsX: " << maxRegionsX << std::endl;
//    std::cout << "maxRegionsY: " << maxRegionsY << std::endl;

    int nrRects = 0;
    int toProduce = maxRegionsX * maxRegionsY;


    int nrY = 1;
    for (int y=borderWidth+regionYoffset ;
         y<=imHeight-regionYoffset+borderWidth ; y+=incrementY)
    {
        if (nrY++ > maxRegionsY)
            continue;
        int nrX = 1;
        for(int x=borderWidth+regionXoffset ;
            x<=imWidth-regionXoffset+borderWidth ; x+=incrementX)
        {
            if (nrX++ > maxRegionsX)
                continue;
            Rectangle rect(x-regionXoffset, y-regionYoffset,
                           x+regionXoffset-1, y+regionYoffset-1);
//            std::cout << "new-rect: " << rect << std::endl;
            *bi++ = rect;
            nrRects++;
        }
    }

    if (nrRects != toProduce)
        std::cout << "MakeSubRects: produced incorrect number: "
                  << nrRects << " instead of " << toProduce << std::endl;
}



} // namespace Geometry
} // namespace Core
} // namespace Impala

#endif

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