#include <iostream>
#include <opencv2/highgui/highgui.hpp>
using namespace std;
using namespace cv;

int main()
{
	Mat src = imread("aaa.png", CV_LOAD_IMAGE_GRAYSCALE);
	src.convertTo(src, CV_32FC1);
	Mat res(src.rows + 4, src.cols + 4, CV_32FC1, Scalar(0));
	Mat srcROI(res, Rect(2, 2, src.cols, src.rows));
	src.copyTo(srcROI);
	for (int i = 2; i < res.rows - 2; ++i)
	{
		for (int j = 2; j < res.cols - 2; ++j)
		{
			float err = 0;
			if (res.ptr<float>(i)[j] < 128)
			{
				err = res.ptr<float>(i)[j];
				res.ptr<float>(i)[j] = 0;
			}
			else
			{
				err = (res.ptr<float>(i)[j] - 255);
				res.ptr<float>(i)[j] = 255;
			}
			res.ptr<float>(i)[j + 1] += (err * 8 / 42.);
			res.ptr<float>(i)[j + 2] += (err * 4 / 42.);
			res.ptr<float>(i + 1)[j - 2] += (err * 2 / 42.);
			res.ptr<float>(i + 1)[j - 1] += (err * 4 / 42.);
			res.ptr<float>(i + 1)[j] += (err * 8 / 42.);
			res.ptr<float>(i + 1)[j + 1] += (err * 4 / 42.);
			res.ptr<float>(i + 1)[j + 2] += (err * 2 / 42.);

			res.ptr<float>(i + 2)[j - 2] += (err * 1 / 42.);
			res.ptr<float>(i + 2)[j - 1] += (err * 2 / 42.);
			res.ptr<float>(i + 2)[j] += (err * 4 / 42.);
			res.ptr<float>(i + 2)[j + 1] += (err * 2 / 42.);
			res.ptr<float>(i + 2)[j + 2] += (err * 1 / 42.);
		}
	}
	srcROI.convertTo(srcROI, CV_8UC1);
	imwrite("ED_1976.jpg", srcROI);
}