does the lib support the RGB444 color?
I dont think so
You can find here https://docs.littlevgl.com/#Porting
and this new documentation type https://littlevgl.com/sphinx/porting/project.html
@ogunduz is correct. We don’t natively support 4-bit color. However, one option is to convert 8-bit color to 4-bit color inside the driver by discarding the least significant 4 bits.