#include <opencv.hpp>

using namespace std;

using namespace cv;

int main(int argc, const char *argv[])

{

        Mat mask = imread("mask.png", -1);

        // Find contours

        vector<Vec4i> hierarchy;

        vector<vector<Point> > contours;

        Mat tmp = mask.clone();

        findContours(tmp, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE);

        // Filter out small contours

        vector<vector<Point> >::iterator cit;

        for (cit = contours.begin(); cit < contours.end();)

        {

                // If contour area is to small skip it

                int contour_area = contourArea(*cit);

                if (contour_area < 100000)

                {

                        cit = contours.erase(cit);

                        continue;

                }

                cit++;

        }

        assert(contours.size() == 1);

        // Find convexHull, print them and notice that they are not all desending

        vector<int> hull;

        convexHull(contours[0], hull);

        cout << "Notice that 1010 to 1011 isn't a decrease in indices like the rest\n";

        for (unsigned int i = 0; i < hull.size(); i++)

        {

                cout << hull.at(i) << endl;

        }

        // Show that the convexityDefects gets messed up because of the convexHull

        {

                vector<Vec4i> convexity_defects;

                convexityDefects(contours[0], hull, convexity_defects);

                // Find the maximum depth convexity defect

                int max_depth = 0;

                int max_index = 0;

                for (unsigned int i = 0; i < convexity_defects.size(); i++)

                {

                        int current_depth = convexity_defects[i][3];

                        if (current_depth > max_depth)

                        {

                                max_depth = current_depth;

                                max_index = i;

                        }

                }

                Mat color_mask;

                cvtColor(mask, color_mask, CV_GRAY2BGR);

                Point start_point = contours[0][convexity_defects[max_index][0]];

                Point end_point = contours[0][convexity_defects[max_index][1]];

                Point defect_point = contours[0][convexity_defects[max_index][2]];

                circle(color_mask, start_point, 26, Scalar(255,255,0), 4);

                circle(color_mask, end_point, 16, Scalar(0,0,255), 4);

                circle(color_mask, defect_point, 16, Scalar(0,255,255), 4);

                namedWindow("defects", CV_WINDOW_NORMAL);

                imshow("defects", color_mask);

                waitKey(0);

        }

        return 0;

}