OpenCV 绘制同心圆的示例代码

// 绘制同心圆
void DrawConcentricCircle(cv::Mat mask, const cv::Point2i &center, int radius1,int radius2, const cv::Scalar &color, int thickness,int linetype)
{
	// 创建画布
	cv::Mat canvas = cv::Mat::zeros(mask.size(), CV_8UC1);
 
	// 计算内径和外径
	int inradius = min(radius1, radius2);
	int outradius = max(radius1, radius2);
 
	// 分情况讨论
	// 当thickness大于0时，绘制的是两个圆型线条组成的同心圆，不需填充
	if (thickness > 0)
	{
		cv::circle(mask, center, outradius, color, thickness, linetype);
		cv::circle(mask, center, inradius, color, thickness, linetype);
	}
	// 当thickness小于0，一般为-1，绘制的是填充同心圆，内圆不能有填充色
	else {
		cv::circle(canvas, center, outradius, cv::Scalar(255), -1, linetype);
		cv::circle(canvas, center, inradius, cv::Scalar(0), -1, linetype);
		int row = mask.rows;
		int col = mask.cols;
		for (int i = 0; i < row; ++i)
		{
			for (int j = 0; j < col; ++j)
			{
				uchar *m = canvas.ptr<uchar>(i);
				if (m[j] == 255)
				{
					mask.at<Vec3b>(i, j)[0] = static_cast<uchar>(color[0]);
					mask.at<Vec3b>(i, j)[1] = static_cast<uchar>(color[1]);
					mask.at<Vec3b>(i, j)[2] = static_cast<uchar>(color[2]);
				}
 
			}
		}
	}
}

#include <iostream>
#include <opencv2/opencv.hpp>
#include <stdio.h>
using namespace std;
using namespace cv;
 
void DrawConcentricCircle(cv::Mat mask, const cv::Point2i &center, int radius1, int radius2, const cv::Scalar &color, int thickness, int linetype);
 
int main()
{
	cv::Mat src = imread("test.jpg");
	cv::Mat result = src.clone();
	DrawConcentricCircle(result, cv::Point(result.cols / 2, result.rows / 2), 300, 500, cv::Scalar(255, 255, 0),-10, 16);
	imshow("original", src);
	imshow("result", result);
	waitKey(0);
	system("pause");
	return 0;
}
 
// 绘制同心圆
void DrawConcentricCircle(cv::Mat mask, const cv::Point2i &center, int radius1,int radius2, const cv::Scalar &color, int thickness,int linetype)
{
	// 创建画布
	cv::Mat canvas = cv::Mat::zeros(mask.size(), CV_8UC1);
 
	// 计算内径和外径
	int inradius = min(radius1, radius2);
	int outradius = max(radius1, radius2);
 
	// 分情况讨论
	// 当thickness大于0时，绘制的是两个圆型线条组成的同心圆，不需填充
	if (thickness > 0)
	{
		cv::circle(mask, center, outradius, color, thickness, linetype);
		cv::circle(mask, center, inradius, color, thickness, linetype);
	}
	// 当thickness小于0，一般为-1，绘制的是填充同心圆，内圆不能有填充色
	else {
		cv::circle(canvas, center, outradius, cv::Scalar(255), -1, linetype);
		cv::circle(canvas, center, inradius, cv::Scalar(0), -1, linetype);
		int row = mask.rows;
		int col = mask.cols;
		for (int i = 0; i < row; ++i)
		{
			for (int j = 0; j < col; ++j)
			{
				uchar *m = canvas.ptr<uchar>(i);
				if (m[j] == 255)
				{
					mask.at<Vec3b>(i, j)[0] = static_cast<uchar>(color[0]);
					mask.at<Vec3b>(i, j)[1] = static_cast<uchar>(color[1]);
					mask.at<Vec3b>(i, j)[2] = static_cast<uchar>(color[2]);
				}
 
			}
		}
	}
}