功能函数
// 绘制圆端矩形（药丸状，pill）void DrawPill(cv::Mat mask, const cv::RotatedRect &rotatedrect, const cv::Scalar &color, int thickness, int lineType){cv::Mat canvas = cv::Mat::zeros(mask.size(), CV_8UC1);// 确定短边，短边绘制圆形cv::RotatedRect rect = rotatedrect;float r = rect.size.height / 2.0f;if (rect.size.width > rect.size.height) {rect.size.width -= rect.size.height;}else {rect.size.height -= rect.size.width;r = rect.size.width / 2.0f;}cv::Point2f ps[4];rect.points(ps); // 绘制边缘std::vector<std::vector<cv::Point>> tmpContours;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(canvas, tmpContours, 0, cv::Scalar(255),5, lineType); // 填充mask // 计算常长短轴float a = rotatedrect.size.width;float b = rotatedrect.size.height; int point01_x = (int)((ps[0].x + ps[1].x) / 2.0f);int point01_y = (int)((ps[0].y + ps[1].y) / 2.0f);int point03_x = (int)((ps[0].x + ps[3].x) / 2.0f);int point03_y = (int)((ps[0].y + ps[3].y) / 2.0f);int point12_x = (int)((ps[1].x + ps[2].x) / 2.0f);int point12_y = (int)((ps[1].y + ps[2].y) / 2.0f);int point23_x = (int)((ps[2].x + ps[3].x) / 2.0f);int point23_y = (int)((ps[2].y + ps[3].y) / 2.0f); cv::Point c0 = a < b ? cv::Point(point12_x, point12_y) : cv::Point(point23_x, point23_y);cv::Point c1 = a < b ? cv::Point(point03_x, point03_y) : cv::Point(point01_x, point01_y); // 长轴两端以填充的方式画圆，直径等于短轴cv::circle(canvas, c0, (int)r, cv::Scalar(255), 5, lineType);cv::circle(canvas, c1, (int)r, cv::Scalar(255), 5, lineType); // 绘制外围轮廓，如果不这样操作，会得到一个矩形加两个圆形，丑。。。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}
测试代码
#include <iostream>#include <opencv2/opencv.hpp> using namespace std;using namespace cv;void DrawPill(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(1000, 800), 50);DrawPill(result, rorect, cv::Scalar(0, 255, 255),8,16);imshow("original", src);imshow("result", result);waitKey(0);return 0;} // 绘制圆端矩形（药丸状，pill）void DrawPill(cv::Mat mask, const cv::RotatedRect &rotatedrect, const cv::Scalar &color, int thickness, int lineType){cv::Mat canvas = cv::Mat::zeros(mask.size(), CV_8UC1);// 确定短边，短边绘制圆形cv::RotatedRect rect = rotatedrect;float r = rect.size.height / 2.0f;if (rect.size.width > rect.size.height) {rect.size.width -= rect.size.height;}else {rect.size.height -= rect.size.width;r = rect.size.width / 2.0f;}cv::Point2f ps[4];rect.points(ps); // 绘制边缘std::vector<std::vector<cv::Point>> tmpContours;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(canvas, tmpContours, 0, cv::Scalar(255),5, lineType); // 填充mask // 计算常长短轴float a = rotatedrect.size.width;float b = rotatedrect.size.height; int point01_x = (int)((ps[0].x + ps[1].x) / 2.0f);int point01_y = (int)((ps[0].y + ps[1].y) / 2.0f);int point03_x = (int)((ps[0].x + ps[3].x) / 2.0f);int point03_y = (int)((ps[0].y + ps[3].y) / 2.0f);int point12_x = (int)((ps[1].x + ps[2].x) / 2.0f);int point12_y = (int)((ps[1].y + ps[2].y) / 2.0f);int point23_x = (int)((ps[2].x + ps[3].x) / 2.0f);int point23_y = (int)((ps[2].y + ps[3].y) / 2.0f);cv::Point c0 = a < b ? cv::Point(point12_x, point12_y) : cv::Point(point23_x, point23_y);cv::Point c1 = a < b ? cv::Point(point03_x, point03_y) : cv::Point(point01_x, point01_y); // 长轴两端以填充的方式画圆，直径等于短轴cv::circle(canvas, c0, (int)r, cv::Scalar(255), 5, lineType);cv::circle(canvas, c1, (int)r, cv::Scalar(255), 5, lineType); // 绘制外围轮廓，如果不这样操作，会得到一个矩形加两个圆形，丑。。。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}
测试效果
图1原图
图2绘制圆端矩形
绘制圆端矩形其实就是绘制了一个旋转矩形，然后分析哪个轴更长，就在哪个轴上的两端画圆，再取外围轮廓，大功告成，通俗来讲就画了一个矩形两个圆，如图3所示。
不过注意，这个图形最好不要超过图像边界，因为超过后再分析外围轮廓，它认为的外围就到了内部，如图4所示。
图4外围线
然后，你就会得到一个奇葩图形，如图5所示。
图5示意图
以上就是使用c++实现OpenCV绘制圆端矩形的详细内容，更多关于c++实现OpenCV绘制圆端矩形的资料请关注其它相关文章！
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