Optimised one assert statement in the min_enclosing_triangle.cpp file. Added the minEnclosingTriangle functionality to the existing minarea.cpp sample file.

modules/imgproc/src/min_enclosing_triangle.cpp

@@ -273,7 +273,7 @@ void cv::minEnclosingTriangle(cv::InputArray points,
                               CV_OUT cv::OutputArray triangle, CV_OUT double& area) {
     std::vector<cv::Point2f> resultingTriangle;
 
-    CV_Assert(triangle.getMat().depth() == CV_32F);
+    CV_Assert(triangle.depth() == CV_32F);
 
     createConvexHull(points);
     findMinEnclosingTriangle(resultingTriangle, area);

samples/cpp/minarea.cpp

@@ -8,12 +8,13 @@ using namespace std;
 
 static void help()
 {
-    cout << "This program demonstrates finding the minimum enclosing box or circle of a set\n"
-            "of points using functions: minAreaRect() minEnclosingCircle().\n"
-            "Random points are generated and then enclosed.\n"
-            "Call:\n"
-            "./minarea\n"
-            "Using OpenCV v" << CV_VERSION << "\n" << endl;
+    cout << "This program demonstrates finding the minimum enclosing box, triangle or circle of a set\n"
+         << "of points using functions: minAreaRect() minEnclosingTriangle() minEnclosingCircle().\n"
+         << "Random points are generated and then enclosed.\n\n"
+         << "Press ESC, 'q' or 'Q' to exit and any other key to regenerate the set of points.\n\n"
+         << "Call:\n"
+         << "./minarea\n"
+         << "Using OpenCV v" << CV_VERSION << "\n" << endl;
 }
 
 int main( int /*argc*/, char** /*argv*/ )
@@ -27,6 +28,8 @@ int main( int /*argc*/, char** /*argv*/ )
     {
         int i, count = rng.uniform(1, 101);
         vector<Point> points;
+
+        // Generate a random set of points
         for( i = 0; i < count; i++ )
         {
             Point pt;
@@ -36,23 +39,39 @@ int main( int /*argc*/, char** /*argv*/ )
             points.push_back(pt);
         }
 
+        // Find the minimum area enclosing bounding box
         RotatedRect box = minAreaRect(Mat(points));
 
+        // Find the minimum area enclosing triangle
+        vector<Point2f> triangle;
+        double area;
+
+        minEnclosingTriangle(points, triangle, area);
+
+        // Find the minimum area enclosing circle
         Point2f center, vtx[4];
         float radius = 0;
         minEnclosingCircle(Mat(points), center, radius);
         box.points(vtx);
 
         img = Scalar::all(0);
+
+        // Draw the points
         for( i = 0; i < count; i++ )
             circle( img, points[i], 3, Scalar(0, 0, 255), FILLED, LINE_AA );
 
+        // Draw the bounding box
         for( i = 0; i < 4; i++ )
             line(img, vtx[i], vtx[(i+1)%4], Scalar(0, 255, 0), 1, LINE_AA);
 
+        // Draw the triangle
+        for( i = 0; i < 3; i++ )
+            line(img, triangle[i], triangle[(i+1)%3], Scalar(255, 255, 0), 1, LINE_AA);
+
+        // Draw the circle
         circle(img, center, cvRound(radius), Scalar(0, 255, 255), 1, LINE_AA);
 
-        imshow( "rect & circle", img );
+        imshow( "Rectangle, triangle & circle", img );
 
         char key = (char)waitKey();
         if( key == 27 || key == 'q' || key == 'Q' ) // 'ESC'