Add CAM02 JCh and CAM02-UCS J'a'b' conversions

* src/lcms.c (rad2deg, parse_jch_list, parse_jab_list, xyz_to_jch):
(jch_to_xyz, jch_to_jab, jab_to_jch): New functions.
(lcms-jch->xyz, lcms-jch->xyz, lcms-jch->jab, lcms-jab->jch): New Lisp
functions.
(lcms-cam02-ucs): Refactor.
(syms_of_lcms2): Declare new functions.
* test/src/lcms-tests.el (lcms-roundtrip, lcms-ciecam02-gold):
(lcms-jmh->cam02-ucs-silver): New tests.
* etc/NEWS: Mention new functions.

1 files changed, 2 insertions, 1 deletions

diff --git a/etc/NEWS b/etc/NEWS
index ab9a2a5f32d..adeee9e6ef2 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -76,7 +76,8 @@ If the lcms2 library is installed, Emacs will enable features built on
 top of that library.  The new configure option '--without-lcms2' can
 be used to build without lcms2 support even if it is installed.  Emacs
 linked to Little CMS exposes color management functions in Lisp: the
-color metrics 'lcms-cie-de2000' and 'lcms-cam02-ucs'.
+color metrics 'lcms-cie-de2000' and 'lcms-cam02-ucs', as well as
+functions for conversion to and from CIE CAM02 and CAM02-UCS.
 
 ** The configure option '--with-gameuser' now defaults to 'no',
 as this appears to be the most common configuration in practice.