这篇文章主要介绍“怎么用OpenCV绘制圆角矩形”,在日常操作中,相信很多人在怎么用OpenCV绘制圆角矩形问题上存在疑惑,小编查阅了各式资料,整理出简单好用的操作方法,希望对大家解答”怎么用OpenCV绘制圆角矩形”的疑惑有所帮助!接下来,请跟着小编一起来学习吧!
// 绘制圆角矩形 void DrawRotatedRectChamfer(cv::Mat mask,const cv::RotatedRect rotatedrect, float radius,const cv::Scalar &color, int thickness, int lineType) { // 创建画布 cv::Mat canvas = cv::Mat::zeros(mask.size(), CV_8UC1); cv::RotatedRect newrotatedrect = rotatedrect; //画宽缩减后的矩形 cv::RotatedRect r1 = newrotatedrect; r1.size.width = r1.size.width - 2 * radius; DrawRotatedRect(canvas, r1, cv::Scalar(255), 5, lineType); //画高缩减后的矩形 cv::RotatedRect r2 = newrotatedrect; r2.size.height = r2.size.height - 2 * radius; DrawRotatedRect(canvas, r2, cv::Scalar(255), 5,lineType); //画四个角的圆 cv::RotatedRect r3 = r2; r3.size.width = r1.size.width; cv::Point2f ps[4]; r3.points(ps); for (int i = 0; i != 4; ++i) { cv::circle(canvas, ps[i], (int)radius, cv::Scalar(255), 5); } std::vector<std::vector<cv::Point>> EXcontours; cv::findContours(canvas, EXcontours, cv::RETR_EXTERNAL, CHAIN_APPROX_SIMPLE); drawContours(mask, EXcontours, 0, color, thickness, lineType); // 填充mask } // 绘制旋转矩形 void DrawRotatedRect(cv::Mat mask,const cv::RotatedRect rotatedrect,const cv::Scalar &color, int thickness,int lineType) { cv::Point2f ps[4]; rotatedrect.points(ps); std::vector<std::vector<cv::Point>> tmpContours; // 创建一个InputArrayOfArrays 类型的点集 std::vector<cv::Point> contours; for (int i = 0; i != 4; ++i) { contours.emplace_back(cv::Point2i(ps[i])); } tmpContours.insert(tmpContours.end(), contours); drawContours(mask, tmpContours, 0, color, thickness, lineType); // 填充mask }
#include <iostream> #include <opencv2/opencv.hpp> #include <stdio.h> using namespace std; using namespace cv; void DrawRotatedRectChamfer(cv::Mat mask, const cv::RotatedRect rotatedrect, float radius, const cv::Scalar &color, int thickness, int lineType); void DrawRotatedRect(cv::Mat mask, const cv::RotatedRect rotatedrect, const cv::Scalar &color, int thickness, int lineType); int main() { cv::Mat src = imread("test.jpg"); cv::Mat result = src.clone(); cv::RotatedRect rorect(cv::Point(src.cols / 2, src.rows / 2), cv::Size(800, 600), 50); DrawRotatedRectChamfer(result, rorect, 100, cv::Scalar(0, 0, 255), 5, 16); imshow("original", src); imshow("result", result); waitKey(0); return 0; } // 绘制圆角矩形 void DrawRotatedRectChamfer(cv::Mat mask,const cv::RotatedRect rotatedrect, float radius,const cv::Scalar &color, int thickness, int lineType) { // 创建画布 cv::Mat canvas = cv::Mat::zeros(mask.size(), CV_8UC1); cv::RotatedRect newrotatedrect = rotatedrect; //画宽缩减后的矩形 cv::RotatedRect r1 = newrotatedrect; r1.size.width = r1.size.width - 2 * radius; DrawRotatedRect(canvas, r1, cv::Scalar(255), 5, lineType); //画高缩减后的矩形 cv::RotatedRect r2 = newrotatedrect; r2.size.height = r2.size.height - 2 * radius; DrawRotatedRect(canvas, r2, cv::Scalar(255), 5,lineType); //画四个角的圆 cv::RotatedRect r3 = r2; r3.size.width = r1.size.width; cv::Point2f ps[4]; r3.points(ps); for (int i = 0; i != 4; ++i) { cv::circle(canvas, ps[i], (int)radius, cv::Scalar(255), 5); } std::vector<std::vector<cv::Point>> EXcontours; cv::findContours(canvas, EXcontours, cv::RETR_EXTERNAL, CHAIN_APPROX_SIMPLE); drawContours(mask, EXcontours, 0, color, thickness, lineType); // 填充mask } // 绘制旋转矩形 void DrawRotatedRect(cv::Mat mask,const cv::RotatedRect rotatedrect,const cv::Scalar &color, int thickness,int lineType) { cv::Point2f ps[4]; rotatedrect.points(ps); std::vector<std::vector<cv::Point>> tmpContours; // 创建一个InputArrayOfArrays 类型的点集 std::vector<cv::Point> contours; for (int i = 0; i != 4; ++i) { contours.emplace_back(cv::Point2i(ps[i])); } tmpContours.insert(tmpContours.end(), contours); drawContours(mask, tmpContours, 0, color, thickness, lineType); // 填充mask }
图1 原图
图2 绘制圆角矩形
绘制圆角矩形其实是绘制了两个旋转矩形,交叉组合,然后以四交点为圆心绘制圆,就组成了圆角矩形,如图3所示。
图3 绘制逻辑
同理,这个最好不要绘制到图像外面,否则它在分析外围线的时候会出错,可以多加些判断来修正,我就不写了,交给兄弟们研究一下~
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