#include <opencv2/opencv.hpp>
#include <math.h>
#include <time.h>
#include <iostream>
#include <iomanip>
#include <vector>

using namespace cv;
using namespace std;

int main() {

    Mat img = imread("input.jpg");

    if (img.empty()) {
        cout << "Can not open or image is not present" << endl;
        return 0;
    }

    Mat img_chromo;

    cvtColor(img, img_chromo, COLOR_BGR2GRAY);

    Mat result(256, 512, CV_8U, 255);

    vector<int> v(256);

    for (int i = 0; i < img_chromo.cols; ++i) {
        for (int j = 0; j < img_chromo.rows; ++j) {
            uchar cur_color = img_chromo.at<uchar>(j, i);
            v[cur_color]++;
        }
    }

    int max_count = *max_element(v.begin(), v.end());

    for (int i = 0; i < 256; ++i) {
        int h = v[i] * 250 / max_count;
        Point pt1(i * 2, 255 - h);
        Point pt2(i * 2 + 1,255);
        rectangle(result, pt1, pt2, 0);
    }



    imshow("result", result);
    imshow("cat", img);
    imshow("cat2", img_chromo);
    waitKey(0);
    return 0;
}