#include <iostream>
#include<opencv.hpp>
#include <vector>
#include<map>
#include<algorithm>
using namespace std;
using namespace cv;

typedef pair<int, int>  pii;

bool comp(pii a, pii b){
	return a.second > b.second;
}

void convertRGB2GRAY(const Mat&image, Mat&imageGray){
	if (!image.data || image.channels() != 3)
		return;
	imageGray = Mat::zeros(image.size(), CV_8UC1);
	uchar*pointImage = image.data;
	uchar*pointImageGray = imageGray.data;
	int stepImage = image.step;
	int stepImageGray = imageGray.step;
	for (int i = 0; i < imageGray.rows; i++){
		for (int j = 0; j < imageGray.cols; j++){
			pointImageGray[i*stepImageGray + j] = 0.114*pointImage[i*stepImage + 3 * j]
				+ 0.587*pointImage[i*stepImage + 3 * j + 1] + 0.299*pointImage[i*stepImage + 3 * j + 2];
		}
	}

}
int main()
{
	Mat image = imread("th.jpg");
	namedWindow("w", CV_WINDOW_AUTOSIZE);
	imshow("w", image);
	Mat imageGray;
	convertRGB2GRAY(image, imageGray);
	namedWindow("g", CV_WINDOW_AUTOSIZE);
	imshow("g", imageGray);
	cout << "row:" << imageGray.rows << ",col:" << imageGray.cols << endl;

	map<int, int>m;
	for (int i = 0; i < imageGray.rows; i++){
		for (int j = 0; j < imageGray.cols; j++){
			m[imageGray.at<uchar>(i, j)]++;
		}
	}

	vector<pii>v(m.begin(),m.end());
	sort(v.begin(), v.end(), comp);
	for (int i = 0; i < v.size(); i++){
		cout << v[i].first << ":" << v[i].second << endl;
	}

	waitKey(0);
	return 0;
}