[malkia]

I've collected few rounded square (squircles :)) codes using cairo (through luajit):

http://cairographics.org/cookbook/roundedrectangles/

http://graphics.stanford.edu/courses/cs248-98-fall/Final/q1....

and two more here (but I forgot to put the links where I got the code from, and I don't recall being my original code):

https://github.com/malkia/ufo/blob/master/samples/cairo/ui.l...

  gfx:round_rect_a()
  gfx:round_rect_b()
  gfx:round_rect_c()
  gfx:round_rect_d()