How to modify shape of button?


I would like to customize the shape of a button component. In this post was mentioned the hooking into the LV_EVENT_DRAW_MAIN, which I read more about in the documentation. However, I am not sure what I can access in those callbacks and how to exactly use it to modify the shape of a outline.
My goal is to have a button that has a radius on one of its rounded corners bigger than the other 3.
Examples or at least hints would be much appreciated.

What MCU/Processor/Board and compiler are you using?

Raspberry Pi 3B+ with linux fbdev display driver and evdev input driver

What LVGL version are you using?


What do you want to achieve?

Make a button have a different/bigger radius on one of its rounded corners