Improve vpMeEllipse::initTracking() to be able to retrieve pixels use…

…d for initialization when initialized by mouse click

modules/tracker/me/include/visp3/me/vpMeEllipse.h

@@ -229,22 +229,47 @@ class VISP_EXPORT vpMeEllipse : public vpMeTracker
   void initTracking(const vpImage<unsigned char> &I, bool trackCircle = false, bool trackArc = false);
 
   /*!
-   * Initialize the tracking of an ellipse/circle or an arc of an ellipse/circle when \e trackArc is set to true.
-   * The ellipse/circle is defined thanks to a vector of image points.
+   * Initialize the tracking of an ellipse or an arc of an ellipse when \e trackArc is set to true.
+   * If \b ips is set, use the contained points to initialize the ME if there are some, or initialize
+   * by clicks the ME and \b ips will contained the clicked points.
+   * If \b ips is not set, call the method vpMeEllispe::initTracking(const vpImage<unsigned char>&, bool, bool).
+   *
+   * \sa \ref vpMeEllispe::initTracking()
    *
-   * \warning It is mandatory to use at least five image points to estimate the
-   * ellipse parameters while three points are needed to estimate the circle parameters.
-   * \warning The image points should be selected as far as possible from each other.
-   * When an arc of an ellipse/circle is tracked, it is recommended to select the 5/3 points clockwise.
+   * \warning The points should be selected as far as possible from each other.
+   * When an arc of an ellipse is tracked, it is recommended to select the 5 points clockwise.
    *
-   * \param I : Image in which the ellipse/circle appears.
-   * \param iP : A vector of image points belonging to the ellipse/circle edge used to
-   * initialize the tracking.
+   * \param I : Image in which the ellipse appears.
+   * \param opt_ips: If set, either a vector that contains the vpImagePoint to use or will be filled with the clicked
+   * points.
    * \param trackCircle : When true, track a circle, when false track an ellipse.
    * \param trackArc : When true track an arc of the ellipse/circle. In that case, first and
    * last points specify the extremities of the arc (clockwise).
    * When false track the complete ellipse/circle.
    */
+#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_17)
+  void initTracking(const vpImage<unsigned char> &I, std::optional<std::vector<vpImagePoint>> &opt_ips, bool trackCircle = false, bool trackArc = false);
+#else
+  void initTracking(const vpImage<unsigned char> &I, std::vector<vpImagePoint> *opt_ips, bool trackCircle = false, bool trackArc = false);
+#endif
+
+/*!
+ * Initialize the tracking of an ellipse/circle or an arc of an ellipse/circle when \e trackArc is set to true.
+ * The ellipse/circle is defined thanks to a vector of image points.
+ *
+ * \warning It is mandatory to use at least five image points to estimate the
+ * ellipse parameters while three points are needed to estimate the circle parameters.
+ * \warning The image points should be selected as far as possible from each other.
+ * When an arc of an ellipse/circle is tracked, it is recommended to select the 5/3 points clockwise.
+ *
+ * \param I : Image in which the ellipse/circle appears.
+ * \param iP : A vector of image points belonging to the ellipse/circle edge used to
+ * initialize the tracking.
+ * \param trackCircle : When true, track a circle, when false track an ellipse.
+ * \param trackArc : When true track an arc of the ellipse/circle. In that case, first and
+ * last points specify the extremities of the arc (clockwise).
+ * When false track the complete ellipse/circle.
+ */
   void initTracking(const vpImage<unsigned char> &I, const std::vector<vpImagePoint> &iP, bool trackCircle = false,
                     bool trackArc = false);
 

modules/tracker/me/src/moving-edges/vpMeEllipse.cpp

@@ -1131,6 +1131,67 @@ void vpMeEllipse::initTracking(const vpImage<unsigned char> &I, bool trackCircle
   initTracking(I, iP, trackCircle, trackArc);
 }
 
+#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_17)
+void vpMeEllipse::initTracking(const vpImage<unsigned char> &I, std::optional<std::vector<vpImagePoint>> &opt_ips, bool trackCircle, bool trackArc)
+#else
+void vpMeEllipse::initTracking(const vpImage<unsigned char> &I, std::vector<vpImagePoint> *opt_ips, bool trackCircle, bool trackArc)
+#endif
+{
+#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_17)
+  if (!opt_ips.has_value())
+#else
+  if (opt_ips == nullptr)
+#endif
+  {
+    initTracking(I, trackCircle, trackArc);
+    return;
+  }
+
+  if (opt_ips->size() != 0) {
+    initTracking(I, *opt_ips, trackCircle, trackArc);
+    return;
+  }
+
+  unsigned int n = 5; // by default, 5 points for an ellipse
+  const unsigned int nForCircle = 3;
+  m_trackCircle = trackCircle;
+  if (trackCircle) {
+    n = nForCircle;
+  }
+  opt_ips->resize(n);
+  m_trackArc = trackArc;
+
+  vpDisplay::flush(I);
+
+  if (m_trackCircle) {
+    if (m_trackArc) {
+      std::cout << "First and third points specify the extremities of the arc of circle (clockwise)" << std::endl;
+    }
+    for (unsigned int k = 0; k < n; ++k) {
+      std::cout << "Click point " << (k + 1) << "/" << n << " on the circle " << std::endl;
+      vpDisplay::getClick(I, (*opt_ips)[k], true);
+      const unsigned int crossSize = 10;
+      vpDisplay::displayCross(I, (*opt_ips)[k], crossSize, vpColor::red);
+      vpDisplay::flush(I);
+      std::cout << (*opt_ips)[k] << std::endl;
+    }
+  }
+  else {
+    if (m_trackArc) {
+      std::cout << "First and fifth points specify the extremities of the arc of ellipse (clockwise)" << std::endl;
+    }
+    for (unsigned int k = 0; k < n; ++k) {
+      std::cout << "Click point " << (k + 1) << "/" << n << " on the ellipse " << std::endl;
+      vpDisplay::getClick(I, (*opt_ips)[k], true);
+      const unsigned int crossSize = 10;
+      vpDisplay::displayCross(I, (*opt_ips)[k], crossSize, vpColor::red);
+      vpDisplay::flush(I);
+      std::cout << (*opt_ips)[k] << std::endl;
+    }
+  }
+  initTracking(I, *opt_ips, trackCircle, trackArc);
+}
+
 void vpMeEllipse::initTracking(const vpImage<unsigned char> &I, const std::vector<vpImagePoint> &iP,
                                bool trackCircle, bool trackArc)
 {