The API should preserve the precision across the public interface so that
the user is able to retrieve the co-ordinates that he used to construct
the path. However since we transform the path to a 24.8 fixed-point
internal represent we currently incur a precision-loss - the affects of
which can be seen in the miter-precision test case for example. It is
planned to move to keeping the path as doubles until the backend
explicitly requests the fixed-point coodinates (and some backends, e.g.
pdf, might only ever use the doubles). Then, barring rounding errors
during path transformations, we should be able to return the exact path
the user set (under an identity CTM, of course ;-).
