retract the HLG/PQ APIs a bit

Rewrite skcms.h to only mention the encoded->linear forward functions,
just like we do for sRGBish transfer functions, and just as
skcms_Transform() expects.  There's little need for anyone to get their
hands on an inverse-PQ or inverse-HLG skcms_TransferFunction except
internally inverting in skcms_Transform() or for testing.

Change-Id: If52b053f8dc0a20659c3e0953170221bdffeeeba
Commit-Queue: Mike Klein <>
Reviewed-by: Brian Osman <>
3 files changed