@haileykim
I don't know exactly, because I'm not a GURU of the luna-surfacemanager which is responsible for graphics management in webOS platform. But, I think this topic (https://www.webosose.org/docs/guides/core-topics/graphics-input/graphics-input-overview/) can help you.
Also, you can find the source code on github : https://github.com/webosose/luna-surfacemanager