OpenCV-绘制圆端矩形（药丸）

// 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
}

#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
}