#include<iostream>
#include<opencv2/opencv.hpp>

using namespace std;
using namespace cv;


int main(int argc, char** argv)
{
	Mat img = imread("./Image/4.png");	// 将一张图片以灰度图加载进来
	if (img.empty()) {
		cout << "图像加载失败" << endl;
		return -1;
	}
	Mat hsv, hs_hist;
	cvtColor(img, hsv, COLOR_BGR2HSV);

	int hbins = 30, sbins = 32;
	int hist_bins[] = { hbins,sbins };
	float h_range[] = { 0,180 };
	float s_range[] = { 0,256 };
	const float* hs_ranges[] = { h_range,s_range };
	int hs_channels[] = { 0,1 };
	calcHist(&hsv, 1, hs_channels, Mat(), hs_hist, 2, hist_bins, hs_ranges, true, false);
	double maxVal = 0;
	minMaxLoc(hs_hist, 0, &maxVal, 0, 0);
	int scale = 10;
	Mat hist2d_img = Mat::zeros(sbins * scale, hbins * scale, CV_8UC3);
	for (int h = 0; h < hbins; h++)
	{
		for (int s = 0; s < sbins; s++)
		{
			double binVal = hs_hist.at<float>(h, s);
			int intensity = cvRound(binVal * 255 / maxVal);
			rectangle(hist2d_img, Point(h * scale, s * scale), 
				Point((h + 1) * scale - 1, (s + 1) * scale - 1),
				Scalar::all(intensity), FILLED);
		}
	}


	namedWindow("原图", WINDOW_NORMAL);
	imshow("原图", img);

	// 显示直方图
	namedWindow("图像直方图", WINDOW_AUTOSIZE);
	applyColorMap(hist2d_img, hist2d_img, COLORMAP_JET);
	imshow("图像直方图", hist2d_img);

	waitKey(0);				// 等待按键
	destroyAllWindows();	// 摧毁所有的窗口
	return 0;
}