Changing Tracking Color with Messages

Instance variables: add color parameters.

class Demo
{
protected:
    ...  

    int min_hue_;
    int max_hue_;
    int min_saturation_;

Constructor: Add a subscriber for /hue_set messages.
Constructor: Init the color parameters.

public:

Demo (ros::NodeHandle & nh):nh_ (nh), it_ (nh_)
{
    ...
    hue_set_sub_ = nh_.subscribe("/hue_set", 1000, 
				 &Demo::hueSetCallback, this);
    min_hue_        =  6;
    max_hue_        = 26;
    min_saturation_ = 96;
}

Callback function: Set new color parameters.

  void hueSetCallback (const geometry_msgs::Point::ConstPtr & hue_set_msg)
  {
    ROS_INFO("*** In hueSetCallback: x: %d   y: %d   z: %d",
	     (int)(hue_set_msg->x), 
             (int)(hue_set_msg->y), 
             (int)(hue_set_msg->z));
    min_hue_        = (int)(hue_set_msg->x);
    max_hue_        = (int)(hue_set_msg->y);
    min_saturation_ = (int)(hue_set_msg->z);
  }