rewrite skcms_TransferFunction_invert

This is mostly me rewriting the code and comments as a way to make sure
I understand the math.

I'm somewhat puzzled that the BenQ_GL2450 profile approximation changes
to skip the linear segment.  I think that's from how I'm now checking
inv.d > 0 for when the linear segment matters?

Change-Id: I0d6ad1093e0c709a2d15fbd509c48f2c312f4cc6
Auto-Submit: Mike Klein <>
Commit-Queue: Brian Osman <>
Reviewed-by: Brian Osman <>
2 files changed