Hi Sorin,
Yes, GDI+ supports Anti-Alias
Check for the GpImage class inside _gdiplus.vcx
Then have a look at "SmoothingMode"
Here are the constants relate to that.
You might be interested in 4 - Anti Alias
#DEFINE SmoothingModeInvalid -1
#DEFINE SmoothingModeDefault 0
#DEFINE SmoothingModeHighSpeed 1
#DEFINE SmoothingModeHighQuality 2
#DEFINE SmoothingModeNone 3
#DEFINE SmoothingModeAntiAlias 4
Regards
Cesar