I was almost sure you meant anti-aliasing. [;)]
SunFlow Antialiasing is set in PhotoRenderer class with aa.min and aa.max values. I don't think I'll add new input fields in the user interface that will let the user set these values. Maybe I'll add more Quality levels that would act on it but not in a close future.
If you're a developer, feel free to download the source code and play with these values directly.