OpenCV像素操作和图形绘制

像素操作

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


using namespace std;
using namespace cv;

int main(int argc, char**argv)
{
    Mat src, src_gray;
    src= imread("b.jpg");
    if (src.empty())
    {
        cout << "could not load img.." << endl;
        return -1;
    }
    namedWindow("input", CV_WINDOW_AUTOSIZE);
    imshow("input", src);
/*
    cvtColor(src, src_gray, CV_BGR2GRAY);
    namedWindow("output", CV_WINDOW_AUTOSIZE);
    imshow("output", src_gray);
    int height= src_gray.rows;
    int width = src_gray.cols;
    for (int row = 0; row < height; ++row)
    {
        for (int col = 0; col < width; ++col)
        {
            int gray = src_gray.at<uchar>(row, col);
            src_gray.at<uchar>(row, col) = 255 - gray;
        }
    }

    imshow("output", src_gray);
*/
    Mat dst;
    dst.create(src.size(), src.type());

    int height = src.rows;
    int width = src.cols;
    int chn = src.channels();

    for(int row=0;row<height;++row)
        for (int col = 0; col < width; ++col)
        {
            if (chn == 1)
            {
                int gray = src_gray.at<uchar>(row, col);
                src_gray.at<uchar>(row, col) = 255 - gray;
            }
            else if(chn==3)
            {
                dst.at<Vec3b>(row, col)[0] = 255 - src.at<Vec3b>(row, col)[0];
                dst.at<Vec3b>(row, col)[1] = 255 - src.at<Vec3b>(row, col)[1];
                dst.at<Vec3b>(row, col)[2] = 255 - src.at<Vec3b>(row, col)[2];

            }
        }
    //bitwise_not(src, dst);
    imshow("dst", dst);
    waitKey(0);
    return 0;
}

直线，举行，圆形，椭圆的绘制与随机直线随机颜色的绘制

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

using namespace std;
using namespace cv;

Mat src;
const char *drawdemo_win = "draw shapes and text demo";
void MyLines();
void MyRectangle();
void MyEclipse();
void MyCircle();
void MyPolygon();
void RandomLineDemo();

int main(int argc, char **argv)
{
    src = imread("b.jpg");
    if (src.empty())
    {
        cout << "Load image failed" << endl;
        return -1;
    }
    imshow("input image", src);
    //MyLines();
    //MyRectangle();
    //MyEclipse();
    //MyCircle();
    //MyPolygon();
    //MyPolygon();
    //putText(src, "Hello OpenCV", Point(300, 300), CV_FONT_HERSHEY_COMPLEX, 1.0, Scalar(12, 255, 255), 3, 8);
    RandomLineDemo();
    imshow("draw", src);
    waitKey(0);

    return 0;
}

void MyLines()
{
    Point p1 = Point(20, 30);
    Point p2;
    p2.x = 400;
    p2.y = 400;
    Scalar color = Scalar(0, 0, 255);
    line(src, p1, p2, color, 1, LINE_AA);
}

void MyRectangle()
{
    Rect rect = Rect(200, 100, 300, 300);
    Scalar color = Scalar(255, 0, 0);
    rectangle(src, rect, color, 2, LINE_8);
}

void MyEclipse()
{
    Scalar color = Scalar(0, 255, 0);
    ellipse(src, Point(src.cols / 2, src.rows / 2), Size(src.cols / 4, src.rows / 8), 30, 0, 90, color, 2, LINE_8);

}

void MyCircle()
{
    Scalar color = Scalar(0,255, 255);
    Point center = Point(src.cols / 2, src.rows / 2);
    circle(src, center, 150,color, 2, 8);
}

void MyPolygon()
{
    Point  pts[1][5];
    pts[0][0] = Point(100, 100);
    pts[0][1] = Point(100, 200);
    pts[0][2] = Point(200, 200);
    pts[0][3] = Point(200, 100);
    pts[0][4] = Point(100, 100);

    const Point *ppts[] = { pts[0] }; 
    int npt[] = { 5 };

    Scalar color = Scalar(255, 13, 255);
    fillPoly(src, ppts, npt, 1, color, 8);
}

void RandomLineDemo()
{
    RNG rng(1334);
    Point pt1;
    Point pt2;
    Mat bg = Mat::zeros(src.size(), src.type());
    namedWindow("Random Line Demo", CV_WINDOW_AUTOSIZE);
    for(int i=0;i<1000000;++i)
    {
        pt1.x = rng.uniform(0, src.cols);
        pt2.x = rng.uniform(0, src.cols);
        pt1.y = rng.uniform(0, src.rows);
        pt2.y = rng.uniform(0, src.rows);
        Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
        if (waitKey(50) > 0)
            break;
        line(bg, pt1, pt2, color, 1, 8);
        imshow("Random Line Demo", bg);
    }
}