Feature #3957

samples/cpp/camshiftdemo.cpp

@@ -47,6 +47,15 @@ static void onMouse( int event, int x, int y, int, void* )
     }
 }
 
+string hot_keys =
+    "\n\nHot keys: \n"
+    "\tESC - quit the program\n"
+    "\tc - stop the tracking\n"
+    "\tb - switch to/from backprojection view\n"
+    "\th - show/hide object histogram\n"
+    "\tp - pause video\n"
+    "To initialize tracking, select the object with mouse\n";
+
 static void help()
 {
     cout << "\nThis is a demo that shows mean-shift based tracking\n"
@@ -54,33 +63,28 @@ static void help()
             "This reads from video camera (0 by default, or the camera number the user enters\n"
             "Usage: \n"
             "   ./camshiftdemo [camera number]\n";
-
-    cout << "\n\nHot keys: \n"
-            "\tESC - quit the program\n"
-            "\tc - stop the tracking\n"
-            "\tb - switch to/from backprojection view\n"
-            "\th - show/hide object histogram\n"
-            "\tp - pause video\n"
-            "To initialize tracking, select the object with mouse\n";
+    cout << hot_keys;
 }
 
 const char* keys =
 {
-    "{@camera_number| 0 | camera number}"
+    "{help h | | show help message}{@camera_number| 0 | camera number}"
 };
 
 int main( int argc, const char** argv )
 {
-    help();
-
     VideoCapture cap;
     Rect trackWindow;
     int hsize = 16;
     float hranges[] = {0,180};
     const float* phranges = hranges;
     CommandLineParser parser(argc, argv, keys);
+    if (parser.has("help"))
+    {
+        help();
+        return 0;
+    }
     int camNum = parser.get<int>(0);
-
     cap.open(camNum);
 
     if( !cap.isOpened() )
@@ -91,7 +95,7 @@ int main( int argc, const char** argv )
         parser.printMessage();
         return -1;
     }
-
+    cout << hot_keys;
     namedWindow( "Histogram", 0 );
     namedWindow( "CamShift Demo", 0 );
     setMouseCallback( "CamShift Demo", onMouse, 0 );