pixelneighbours.hpp

#ifndef PASTELGFX_PIXELNEIGHBOURS_HPP
#define PASTELGFX_PIXELNEIGHBOURS_HPP

#include "pastel/gfx/image_processing/pixelneighbours.h"
#include "pastel/sys/ensure.h"

namespace Pastel
{

    namespace
    {

        inline bool check(const Array<bool, 2>& image,
            integer x, integer y)
        {
            if (x < 0 || x >= image.width() ||
                y < 0 || y >= image.height())
            {
                return false;
            }

            return image(x, y);
        }

    }

    inline integer pixelNeighbours(
        const Array<bool, 2>& image,
        integer x, integer y)
    {
        integer width = image.width();
        integer height = image.height();

        ENSURE2(x >= 0 && x < width, x, width);
        ENSURE2(y >= 0 && y < height, y, height);

        integer result = 0;

        if (check(image, x + 1, y))
        {
            ++result;
        }
        if (check(image, x + 1, y + 1))
        {
            ++result;
        }
        if (check(image, x, y + 1))
        {
            ++result;
        }
        if (check(image, x - 1, y + 1))
        {
            ++result;
        }
        if (check(image, x - 1, y))
        {
            ++result;
        }
        if (check(image, x - 1, y - 1))
        {
            ++result;
        }
        if (check(image, x, y - 1))
        {
            ++result;
        }
        if (check(image, x + 1, y - 1))
        {
            ++result;
        }

        return result;
    }

    inline uint32 pixelNeighbourMask(
        const Array<bool, 2>& image,
        integer x, integer y)
    {
        integer width = image.width();
        integer height = image.height();

        ENSURE2(x >= 0 && x < width, x, width);
        ENSURE2(y >= 0 && y < height, y, height);

        uint32 result = 0;

        if (check(image, x + 1, y))
        {
            result += 1;
        }
        if (check(image, x + 1, y + 1))
        {
            result += 2;
        }
        if (check(image, x, y + 1))
        {
            result += 4;
        }
        if (check(image, x - 1, y + 1))
        {
            result += 8;
        }
        if (check(image, x - 1, y))
        {
            result += 16;
        }
        if (check(image, x - 1, y - 1))
        {
            result += 32;
        }
        if (check(image, x, y - 1))
        {
            result += 64;
        }
        if (check(image, x + 1, y - 1))
        {
            result += 128;
        }

        return result;
    }

}

#endif