#include "opencv2/imgproc/imgproc.hpp"

#include "opencv2/highgui/highgui.hpp"

#include <fstream>

#include <iostream>

using namespace cv;

using namespace std;

static void help()

{

    cout << "\nThis sample program demonstrates the use of the convexHull() function\n"

         << "Call:\n"

         << "./convexhull\n" << endl;

}

int main( int argc, char** argv )

{

    CommandLineParser parser(argc, argv, "{help h||}");

    if (parser.has("help"))

    {

        help();

        return 0;

    }

    Mat img(500, 500, CV_8UC3);

    RNG& rng = theRNG();

    for(;;)

    {

        char key;

        int i, count = (unsigned)rng%100 + 1;

        vector<Point> points;

        for( i = 0; i < count; i++ )

        {

            Point pt;

            pt.x = rng.uniform(img.cols/4, img.cols*3/4);

            pt.y = rng.uniform(img.rows/4, img.rows*3/4);

            points.push_back(pt);

        }

        // Jeff --> hull is the indice of corner points

        vector<int> hull;

        convexHull(Mat(points), hull, true);

/******************************************************************************/

        // Jeff --> draw the effect.

        img = Scalar::all(0);

        for( i = 0; i < count; i++ )

            circle(img, points[i], 3, Scalar(0, 0, 255), FILLED, LINE_AA);

        int hullcount = (int)hull.size();

        cout << hullcount << endl;

        Point pt0 = points[hull[hullcount-1]];

        for( i = 0; i < hullcount; i++ )

        {

            // Jeff --> extract corners.

            Point pt = points[hull[i]];

            line(img, pt0, pt, Scalar(0, 255, 0), 1,LINE_AA);

            pt0 = pt;

        }

        imshow("hull", img);

        key = (char)waitKey();

        if( key == 27 || key == 'q' || key == 'Q' ) // 'ESC'

            break;

    }

    return 0;

}