I need to calculate $\pi$ -- in base: 4, 12, 32, and 128 -- to an arbitrary number of digits. (It's for an artist friend).

I remember Taylor series and I've found miscellaneous ["BBP" formulas](http://mathworld.wolfram.com/BBP-TypeFormula.html), but so far, nothing that points to calculating the digits in arbitrary bases. 

How can this be done in a practical manner?