OpenCV学习笔记（六）：绘制几何图形

主要参考了毛星云等著《OpenCV3编程入门》学习了在OpenCV中绘制一些几何图形，包括线段、圆形、矩形、椭圆形、多边形等。由于代码比较简单，直接上代码了，相信大家应该可以看懂。

#include
using namespace cv;
#define WINDOW_WIDTH 400

void DrawEllipse(Mat img, double angle); //画椭圆形
void DrawCircle(Mat img, Point center); //画圆形
void DrawPolygon(Mat img); //画凹多边形
void DrawLine(Mat img, Point start, Point end); //画线段


int main()
{
	Mat srcimg = Mat::zeros(WINDOW_WIDTH, WINDOW_WIDTH, CV_8UC3);
	Mat dstimg = Mat::zeros(WINDOW_WIDTH, WINDOW_WIDTH, CV_8UC3);

	//画椭圆形
	DrawEllipse(srcimg, 90);
	//画圆形
	Point center(srcimg.cols / 2, srcimg.rows / 2);
	DrawCircle(srcimg, center);
    //画凹多边形
	DrawPolygon(dstimg);
	//画线段
	Point start(30, 30), end(200, 200);
	DrawLine(srcimg, start, end);
	//画矩形
	rectangle(srcimg,
		Point(0, 100),
		Point(50, 200),
		Scalar(0, 255, 255),
		-1,
		8);

	imshow("srcimg", srcimg);
	imshow("dstimg", dstimg);
	waitKey(0);
	return 0;
}

//画椭圆形
void DrawEllipse(Mat img, double angle)
{
	int thickness = -2; //当thickness<0时，为实心，大于0时为空心。
	int lineType = 8;
	 
	ellipse(img,
		Point(img.rows / 2, img.cols / 2),
		Size(img.rows / 4, img.cols / 16),
		angle,
		0,
		360,
		Scalar(255, 129, 0),
		thickness,
		lineType
		);
}

//画圆形
void DrawCircle(Mat img, Point center)
{
	int thickness = 50;
	int lineType = 8;

	circle(img,
		center,
		img.rows / 32,
		Scalar(0, 0, 255),
		thickness,
		lineType
		);
}

//画凹多边形
void DrawPolygon(Mat img)
{
	int lineType = 8;
	
	Point rookPoints[1][20];
	rookPoints[0][0] = Point(WINDOW_WIDTH / 4, 7 * WINDOW_WIDTH / 8);
	rookPoints[0][1] = Point(3 * WINDOW_WIDTH / 4, 7 * WINDOW_WIDTH / 8);
	rookPoints[0][2] = Point(3 * WINDOW_WIDTH / 4, 13 * WINDOW_WIDTH / 16);
	rookPoints[0][3] = Point(11 * WINDOW_WIDTH / 16, 13 * WINDOW_WIDTH / 16);
	rookPoints[0][4] = Point(19 * WINDOW_WIDTH / 32, 3 * WINDOW_WIDTH / 8);
	rookPoints[0][5] = Point(3 * WINDOW_WIDTH / 4, 3 * WINDOW_WIDTH / 8);
	rookPoints[0][6] = Point(3 * WINDOW_WIDTH / 4, WINDOW_WIDTH / 8);
	rookPoints[0][7] = Point(26 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 8);
	rookPoints[0][8] = Point(26 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 4);
	rookPoints[0][9] = Point(22 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 4);
	rookPoints[0][10] = Point(22 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 8);
	rookPoints[0][11] = Point(18 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 8);
	rookPoints[0][12] = Point(18 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 4);
	rookPoints[0][13] = Point(14 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 4);
	rookPoints[0][14] = Point(14 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 8);
	rookPoints[0][15] = Point(WINDOW_WIDTH / 4, WINDOW_WIDTH / 8);
	rookPoints[0][16] = Point(WINDOW_WIDTH / 4, 3 * WINDOW_WIDTH / 8);
	rookPoints[0][17] = Point(13 * WINDOW_WIDTH / 32, 3 * WINDOW_WIDTH / 8);
	rookPoints[0][18] = Point(5 * WINDOW_WIDTH / 16, 13 * WINDOW_WIDTH / 16);
	rookPoints[0][19] = Point(WINDOW_WIDTH / 4, 13 * WINDOW_WIDTH / 16);

	const Point* ppt[1] = { rookPoints[0] };
	int npt[] = { 20 };

	fillPoly(img,
		ppt,
		npt,
		1,
		Scalar(255, 255, 255),
		lineType );
}

//画线段
void DrawLine(Mat img, Point start, Point end)
{
	int thickness = 2;
	int lineType = 8;
	line(img,
		start,
		end,
		Scalar(255, 255, 255),
		thickness,
		lineType);
}