box() and triangle() have well-defined, trivially verifiable numerical
inverses.
We could actually pre-compute and hard-code the numerical inverse of all
non-parametric kernels, but I'm a bit reluctant to do this as I have plans to
adjust the value of SWS_MAX_REDUCE_CUTOFF based on the desired bit depth of the
output, which makes a hard-coding approach unfeasible.
(It would also be a brittle solution that may break whenever we extend the
scaler configuration API, as well as making it harder to add new filters)
Signed-off-by: Niklas Haas <git@haasn.dev>
Niklas Haas
c1ff2c24b5