This package allows one to use a TV as a virtual whiteboard for a robot. Rather than the robot actually holding a drawing implement, you can run the whiteboard.py node and turn the TV into a whiteboard.
This package was developed on ROS noetic and Ubuntu 20.04. In addition to the python libraries that come bundled with ROS, the following Python libraries are required:
You'll need to change the "img_path" ros parameter in whiteboard_params.yaml to match your system.
After dropping this package into your ROS workspace, don't forget to do the usual steps: chmod +x *.py in the root directory of this repository and catkin_make in the root of your ROS workspace, and maybe source devel/setup.bash.
First, set the screen_w_px and screen_h_px parameters in whiteboard_params.yaml to match the width and height, in pixels, of the screen you'll be using as a whiteboard. Set screen_w_meters to the width of your screen, in meters.
Launch the node with virtual_whiteboard.launch, which just loads the parameter file into ROS parameter server and launches the whiteboard.py node.
To test that things are working without hooking up a real robot, you can run the spoof_marker.py node (rosrun virtual_whiteboard spoof_marker.py). This just publishes a line of points to the /marker_position topic. You should see a line drawn across your screen. Each sweep across the screen, the type should change from drawing, to spraying, to erasing, and back.
whiteboard.py listens to the /marker_position topic to know where to draw. /marker_position is a custom msg type called Marker, which contains the x and y position in meters to draw at, the radius of the mark to make, and the mode of drawing, which can be one of: "draw", "erase", or "spray". The origin is the bottom right corner of the screen, x goes to the right if you're facing the screen, and y goes up.
The status of the tracing is published to the /whiteboard_status topic. "not started" means no drawing has been done since the program launched or it was last reset. "started" means drawing has occurred but not inside of the endpoint. "finished" means drawing has occurred inside the endpoint. The endpoint is set manually per svg file in whiteboard_params.yaml.
The whiteboard.py node has a handler for the virtual_whiteboard/Clear service, which erases drawings from the board, and resets the status to "not started". You can call the service from the command line with:
rosservice call /clear