driver :DRIVER_FILL_AREA defined but don't know how to use it

[ZanoZ]

Dear my friends:

In the code , there are the define of DRIVER_FILL_AREA, but there are no samples , how to write the porting code .
I tried some ,but faild
The uGUI has too many forks and too many changes.
Can anyone helps?
THANKS.
sorry for my pool english, hope you can get my point and Thanks for you time reading this. :)