目的：

使用cv::Point與cv::Scalar

繪制線、矩形、園、橢圓等基本幾何形狀

繪制點和圓

void cvCircle( CvArr* img, CvPoint center, int radius, CvScalar color,
               int thickness=1, int line_type=8, int shift=0 );

void ellipse(Mat& img, Point center, Size axes, double angle, double startAngle, double endAngle, 
	const Scalar& color, int thickness = 1, int lineType = 8, int shift = 0)

 void rectangle(Mat& img,Rect rec, const Scalar&color, intthickness=1, intlineType=8,intshift=0 )

繪制直線

void line(InputOutputArray img, Point pt1, Point pt2, const Scalar& color,
                     int thickness = 1, int lineType = LINE_8, int shift = 0);

cv::RNG

生成高斯隨機數gaussian (double sigma)

生成正態分布隨機數uniform (int a, int b)

代碼：

#include <opencv2\opencv.hpp>

using namespace cv;
using namespace std;


int main()
{
	Mat src;
	src = imread("D:/opencvSRC/test.jpg");
	if (src.empty()) {

		printf("load image error!\n");
	}
	namedWindow("src", CV_WINDOW_AUTOSIZE);

	//畫空心點
	Point p(20, 20);//初始化點坐標為(20,20)
	circle(src, p, 2, Scalar(0, 255, 0)); //第三個參數表示點的半徑，第四個參數選擇顏色。這樣子我們就畫出了綠色的空心點

										  //這種初始化點的方式也可以
	Point p2;
	p2.x = 100;
	p2.y = 100;
	//畫實心點
	circle(src, p2, 3, Scalar(255, 0, 0), -1); //第五個參數我設為-1，表明這是個實點。

											   //畫空心圓
	Point p3(300, 300);
	circle(src, p3, 100, Scalar(0, 0, 255), 3);//第五個參數我們調高點，讓線更粗

											   //畫實心圓
	Point p4;
	p4.x = 600;
	p4.y = 600;
	circle(src, p4, 100, Scalar(120, 120, 120), -1);


	int thickness = 3;
	int lineType = 8;
	double angle = 30;  //橢圓旋轉角度
						//第三個參數Size中的兩個參數分別是橫軸長、縱軸長。
						//同理，thickness若是小于0，表示實心
	ellipse(src, Point(100, 100), Size(90, 60), angle, 0, 300, Scalar(255, 255, 0), thickness, lineType);

	//矩形
	Rect r(250, 250, 120, 200);
	rectangle(src, r, Scalar(0, 255, 255), 3);

	Point p5(100, 100);
	Point p6(758, 50);
	line(src, p5, p6, Scalar(33, 33, 133), 2);

	//畫第二條線
	line(src, Point(300, 300), Point(758, 300), Scalar(89, 90, 90), 3);

	imshow("src", src);



	RNG rng(12345);
	Point pt1;
	Point pt2;
	Mat bg = Mat::zeros(src.size(), src.type());
	namedWindow("randomlinedemo", CV_WINDOW_AUTOSIZE);
	for (int i = 0; i < 1000; 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, rng.uniform(0, 20), 8);
		imshow("randomlinedemo", bg);
	}

	waitKey(0);
	return 0;
}

效果：