SquareNeighborhood.h

// Square Neighbourhood structure inferface
// Written by Sergey G. Kosov in 2015 for Project X
#pragma once

namespace DirectGraphicalModels { namespace fex
{
    typedef struct SqNeighbourhood
    {
        int leftGap;        
        int rightGap;       
        int upperGap;       
        int lowerGap;       
    } SqNeighbourhood;

    enum BasePointLocation {
        BP_CENTER,          
        BP_LEFT,            
        BP_RIGHT,           
        BP_TOP,             
        BP_BOTTOM           
    };

    inline SqNeighbourhood sqNeighbourhood(int leftGap, int rightGap, int upperGap, int lowerGap)
    {
        SqNeighbourhood nbhd;
        nbhd.leftGap    = leftGap;
        nbhd.rightGap   = rightGap;
        nbhd.upperGap   = upperGap;
        nbhd.lowerGap   = lowerGap;
        return nbhd;
    }
    inline SqNeighbourhood sqNeighbourhoodAll(int R) { return sqNeighbourhood(R, R, R, R); }
    inline SqNeighbourhood sqNeighbourhood(int R, BasePointLocation location = BP_CENTER)
    {
        SqNeighbourhood nbhd = sqNeighbourhoodAll(R);
        switch (location) {
            case BP_CENTER:
                break;
            case BP_LEFT:
                nbhd.leftGap    = 0;
                nbhd.rightGap   = 2 * R;
                break;
            case BP_RIGHT:
                nbhd.leftGap    = 2 * R;
                nbhd.rightGap   = 0;
                break;
            case BP_TOP:
                nbhd.upperGap   = 0;
                nbhd.lowerGap   = 2 * R;
                break;
            case BP_BOTTOM:
                nbhd.upperGap   = 2 * R;
                nbhd.lowerGap   = 0;
                break;
        }
        return nbhd;
    }
} }