mat遍历像素并显示

// t1.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include "iostream"
#include "cv.h"
#include "highgui.h"
#include "opencv2/opencv.hpp"

using namespace std;
using namespace cv;

int _tmain(int argc, _TCHAR* argv[])
{
    Mat grayim(600, 800, CV_8UC1);
    Mat colorim(600, 800, CV_8UC3);
    //遍历所有像素，并设置像素值
    for ( int i = 0; i < grayim.rows; ++i )
        for (int j = 0; j < grayim.cols; ++j)
            grayim.at<uchar>(i, j) - (i + j)%255;

    //遍历所有像素，并设置像素值
    for ( int i = 0; i < colorim.rows; ++i)
        for ( int j = 0; j < colorim.cols; ++j)
        {
            Vec3b pixel;
            pixel[0] = i % 255;    //blue
            pixel[1] = j % 255; //green
            pixel[2] = 0;        //red
            colorim.at<Vec3b>(i, j) = pixel;
        }
        
        //显示结果
        imshow("grayim", grayim);
        imshow("colorim", colorim);
        waitKey(0);
        return 0;
}