这篇教程OpenCV绘制圆端矩形的示例代码写得很实用，希望能帮到您。
本文主要介绍了OpenCV绘制圆端矩形的示例代码，分享给大家，具体如下:
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。 
图3 绘制逻辑 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 到此这篇关于OpenCV绘制圆端矩形的示例代码的文章就介绍到这了,更多相关OpenCV 圆端矩形内容请搜索51zixue.net以前的文章或继续浏览下面的相关文章希望大家以后多多支持51zixue.net！
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