//
// Copyright 2019 Miral Shah <miralshah2211@gmail.com>
//
// Use, modification and distribution are subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
#include <boost/gil/image_processing/threshold.hpp>
#include <boost/gil/image_view.hpp>
#include <boost/gil/algorithm.hpp>
#include <boost/gil/gray.hpp>
#include <boost/core/lightweight_test.hpp>


namespace gil = boost::gil;

int height = 4;
int width = 4;

gil::gray8_image_t original_gray(width, height), threshold_gray(width, height),
expected_gray(width, height);

gil::rgb8_image_t original_rgb(width, height), threshold_rgb(width, height),
expected_rgb(width, height);


void fill_original_gray()
{
    //filling original_gray view's upper half part with gray pixels of value 50
    //filling original_gray view's lower half part with gray pixels of value 150
    gil::fill_pixels(gil::subimage_view(gil::view(original_gray), 0, 0, original_gray.width(),
        original_gray.height() / 2), gil::gray8_pixel_t(50));
    gil::fill_pixels(gil::subimage_view(gil::view(original_gray), 0, original_gray.height() / 2,
        original_gray.width(), original_gray.height() / 2), gil::gray8_pixel_t(150));
}

void fill_original_rgb()
{
    //filling original_rgb view's upper half part with rgb pixels of value 50, 155, 115
    //filling original_rgb view's lower half part with rgb pixels of value 203, 9, 60
    gil::fill_pixels(gil::subimage_view(gil::view(original_rgb), 0, 0, original_rgb.width(),
        original_rgb.height() / 2), gil::rgb8_pixel_t(50, 155, 115));
    gil::fill_pixels(gil::subimage_view(gil::view(original_rgb), 0, original_rgb.height() / 2,
        original_rgb.width(), original_rgb.height() / 2), gil::rgb8_pixel_t(203, 9, 60));
}

void binary_gray_to_gray()
{
    //expected_gray view after thresholding of the original_gray view with threshold_gray value of 100
    //filling expected_gray view's upper half part with gray pixels of value 0
    //filling expected_gray view's lower half part with gray pixels of value 255
    gil::fill_pixels(gil::subimage_view(gil::view(expected_gray), 0, 0, original_gray.width(),
        original_gray.height() / 2), gil::gray8_pixel_t(0));
    gil::fill_pixels(gil::subimage_view(gil::view(expected_gray), 0, original_gray.height() / 2,
        original_gray.width(), original_gray.height() / 2), gil::gray8_pixel_t(255));

    gil::threshold_binary(gil::view(original_gray), gil::view(threshold_gray), 100);

    //comparing threshold_gray view generated by the function with the expected_gray view
    BOOST_TEST(gil::equal_pixels(gil::view(threshold_gray), gil::view(expected_gray)));
}

void binary_inverse_gray_to_gray()
{
    //expected_gray view after thresholding of the original_gray view with threshold_gray value of 100
    //filling expected_gray view's upper half part with gray pixels of value 200
    //filling expected_gray view's lower half part with gray pixels of value 0
    gil::fill_pixels(gil::subimage_view(gil::view(expected_gray), 0, 0, original_gray.width(),
        original_gray.height() / 2), gil::gray8_pixel_t(200));
    gil::fill_pixels(gil::subimage_view(gil::view(expected_gray), 0, original_gray.height() / 2,
        original_gray.width(), original_gray.height() / 2), gil::gray8_pixel_t(0));

    gil::threshold_binary
    (
        gil::view(original_gray),
        gil::view(threshold_gray),
        100,
        200,
        gil::threshold_direction::inverse
    );

    //comparing threshold_gray view generated by the function with the expected_gray view
    BOOST_TEST(gil::equal_pixels(gil::view(threshold_gray), gil::view(expected_gray)));
}

void binary_rgb_to_rgb()
{
    //expected_rgb view after thresholding of the original_rgb view with threshold value of 100
    //filling expected_rgb view's upper half part with rgb pixels of value 0, 165, 165
    //filling expected_rgb view's lower half part with rgb pixels of value 165, 0, 0 
    gil::fill_pixels(gil::subimage_view(gil::view(expected_rgb), 0, 0, original_rgb.width(),
        original_rgb.height() / 2), gil::rgb8_pixel_t(0, 165, 165));
    gil::fill_pixels(gil::subimage_view(gil::view(expected_rgb), 0, original_rgb.height() / 2,
        original_rgb.width(), original_rgb.height() / 2), gil::rgb8_pixel_t(165, 0, 0));

    gil::threshold_binary(gil::view(original_rgb), gil::view(threshold_rgb), 100, 165);

    //comparing threshold_rgb view generated by the function with the expected_rgb view
    BOOST_TEST(gil::equal_pixels(gil::view(threshold_rgb), gil::view(expected_rgb)));
}

void binary_inverse_rgb_to_rgb()
{
    //expected_rgb view after thresholding of the original_rgb view with threshold value of 100
    //filling expected_rgb view's upper half part with rgb pixels of value 90, 0, 0 
    //filling expected_rgb view's lower half part with rgb pixels of value 0, 90, 90
    gil::fill_pixels(gil::subimage_view(gil::view(expected_rgb), 0, 0, original_rgb.width(),
        original_rgb.height() / 2), gil::rgb8_pixel_t(90, 0, 0));
    gil::fill_pixels(gil::subimage_view(gil::view(expected_rgb), 0, original_rgb.height() / 2,
        original_rgb.width(), original_rgb.height() / 2), gil::rgb8_pixel_t(0, 90, 90));

    gil::threshold_binary
    (
        gil::view(original_rgb),
        gil::view(threshold_rgb),
        100,
        90,
        gil::threshold_direction::inverse
    );

    //comparing threshold_rgb view generated by the function with the expected_rgb view
    BOOST_TEST(gil::equal_pixels(gil::view(threshold_rgb), gil::view(expected_rgb)));
}


int main()
{
    fill_original_gray();
    fill_original_rgb();
    
    binary_gray_to_gray();
    binary_inverse_gray_to_gray();
    binary_rgb_to_rgb();
    binary_inverse_rgb_to_rgb();

    return boost::report_errors();
}