天天向上

cv::Mat img(cv::Size(800, 800), CV_8UC3);

   // big region of interest (ROI)

   Rect roi(100, 100, 400, 400);

   rectangle(img, roi, Scalar(255, 0, 0), 1);

   // some rectangles

   vector<Rect> lpROIs;

   lpROIs.push_back(Rect(30, 50, 100, 100));

   lpROIs.push_back(Rect(420, 250, 100, 100));

   lpROIs.push_back(Rect(150, 140, 100, 100));

   lpROIs.push_back(Rect(300, 100, 100, 100));

   lpROIs.push_back(Rect(250, 250, 100, 100));

   lpROIs.push_back(Rect(300, 450, 100, 100));

   // check out if the rectangle inside the ROI

   for(int i=0; i<lpROIs.size(); i++)

   {

       // inside the ROI

       if( (roi&lpROIs[i])==lpROIs[i] )

           rectangle(img, lpROIs[i], Scalar(0,0,255), -1);

       else

           rectangle(img, lpROIs[i], Scalar(0,255,0), 1);

   }

   imshow("img", img);

   waitKey();

// check out if the rectangle inside the ROI

for(int i=0; i<lpROIs.size(); i++)

{

   // inside the ROI

   if( (roi&lpROIs[i])==lpROIs[i] )

   {

       rectangle(img, lpROIs[i], Scalar(0,0,255), -1);

   }

   else

   {

       auto a1 = (roi&lpROIs[i]).area();

       auto a2 = lpROIs[i].area();

       double ratio = (double)a1/(double)a2;

       QString r = QString::number(ratio);

       rectangle(img, lpROIs[i], Scalar(0,255,0), 1);

       putText(img, r.toStdString(), lpROIs[i].tl(), FONT_HERSHEY_PLAIN, 1, Scalar(0,255,0), 1);

   }

}