image_eroding.hpp

#ifndef PASTELGFX_IMAGE_ERODING_HPP
#define PASTELGFX_IMAGE_ERODING_HPP

#include "pastel/gfx/image_processing/image_eroding.h"

#include "pastel/sys/ensure.h"

namespace Pastel
{

    namespace ImageEroding_
    {

        namespace Erode
        {

            template <
                typename Image_ConstView,
                typename Element_ConstView>
            bool contains(
                const ExtendedConstView<2, bool, Image_ConstView>& image,
                const ConstView<2, bool, Element_ConstView>& element,
                integer x,
                integer y)
            {
                integer elementWidth = element.width();
                integer elementHeight = element.height();

                for (integer i = 0;i < elementHeight;++i)
                {
                    for (integer j = 0;j < elementWidth;++j)
                    {

                        if (element(j, i) &&
                            !image(x + j, y + i))
                        {
                            return false;
                        }
                    }
                }

                return true;
            }

        }

    }

    template <
        typename Input_ConstView,
        typename Element_ConstView,
        typename Output_View>
        void erode(
        const ExtendedConstView<2, bool, Input_ConstView>& input,
        const ConstView<2, bool, Element_ConstView>& element,
        const View<2, bool, Output_View>& output,
        integer xPivot,
        integer yPivot)
    {
        integer width = input.width();
        integer height = input.height();

        for (integer y = 0;y < height;++y)
        {
            for (integer x = 0;x < width;++x)
            {
                output(x, y) = ImageEroding_::Erode::contains(input, element, x - xPivot, y - yPivot);
            }
        }
    }

    template <
        typename Input_ConstView,
        typename Element_ConstView,
        typename Output_View>
        void erode(
        const ExtendedConstView<2, bool, Input_ConstView>& input,
        const ConstView<2, bool, Element_ConstView>& element,
        const View<2, bool, Output_View>& output)
    {
        Vector<integer, 2> center(
            element.extent() / 2);
        erode(input, element, output, center.x(), center.y());
    }

}

#endif