Use the P2D, P3D or OPENGL renderer.

The Processing version, mode and renderer are all relevant. My comments were in regard to Processing 1.5.1 default mode in which P2D and P3D are custom software renderers and OPENGL is an OpenGL renderer. In Processing 1.5.1 when using these renderers the jagged edges are completely gone for me. But apparantly you are using a 2.0 beta, since you can only pass a number to smooth in the 2.0 beta's. In the 2.0 beta's P2D, P3D and OPENGL are all a newly developed OPENGL renderer. However if you want to use Pjs this is probably another type of renderer again, so any results in any of the other renderers may be useless. I never use Pjs so can't comment on anti-aliasing in this. For Pjs questions you can use the "Processing with Other Languages" section of the forum. So it kind of depends what you want exactly.

Ok, thanks for taking the time to help me out, and the info about the renders in 2.0, very interesting. I'll take this up over in the other forum, since yeah this will ultimately be at the mercy of javascript.