Requirements describe : modify turtlesim Tortoise displays the background color of the node form , It is known that the background color is displayed in the form of parameter server rgb The way to set up .
Result demonstration :

Implementation process :

• adopt ros Command to get parameters .
• Code to implement the service parameter setting node .
• start-up roscore、turtlesim_node And parameter setting node , View the run results .

1 Parameter name acquisition

 Get parameter list :
	rosparam list
	 In response to the results :
	/turtlesim/background_b
	/turtlesim/background_g
	/turtlesim/background_r

2 Parameters change (C++)

/*  Pay attention to the use of namespaces . */
#include "ros/ros.h"


int main(int argc, char *argv[])
{
    
    ros::init(argc,argv,"haha");

    ros::NodeHandle nh("turtlesim");
    //ros::NodeHandle nh;

    // ros::param::set("/turtlesim/background_r",0);
    // ros::param::set("/turtlesim/background_g",0);
    // ros::param::set("/turtlesim/background_b",0);

    nh.setParam("background_r",0);
    nh.setParam("background_g",0);
    nh.setParam("background_b",0);


    return 0;
}

3 function

• First , start-up roscore;
• Then start the background color setting node ;
• Finally, start the tortoise display node ;
• The final execution result is similar to the demonstration result .
  PS: Note the node startup sequence , If you start the tortoise display node first , After the node is started, the background color is set , Then the color setting will not take effect .

4 Modify parameters in other ways

The way 1: Modify the background color of the little turtle node ( Terminal code implementation )

rosparam set /turtlesim/background_b  Custom values 
rosparam set /turtlesim/background_g  Custom values 
rosparam set /turtlesim/background_r  Custom values 

The way 2: When starting the node , Set parameters directly

rosrun turtlesim turtlesim_node _background_r:=100 _background_g=0 _background_b=0