[argyllcms] colprof: shaper curves for -ni -no and -np switches
- From: "Guy K. Kloss" <g.kloss@xxxxxxxxxxxx>
- To: "argyllcms@xxxxxxxxxxxxx" <argyllcms@xxxxxxxxxxxxx>
- Date: Wed, 18 Nov 2009 15:10:47 +1300
Hi,
I've just realised that when using the -ni -no and -np switches to turn off
the A and B shaper curves (input/output tables), Argyll still creates
extensive tables (with 1024 entries), which however then resemble an identity
curve:
$ iccdump -t A2B0 argyll_profile.icc
Lut16:
Input Channels = 3
Output Channels = 3
CLUT resolution = 17
Input Table entries = 1024
Output Table entries = 1024
XYZ matrix = 1.000000, 0.000000, 0.000000
0.000000, 1.000000, 0.000000
0.000000, 0.000000, 1.000000
I've tested another profile (not created with Argyll) that creates a very
sparse output table with only two elements for the beginning/end of the
identity curve. It's not a big issue as it should result only in a few KB of
extra memory in RAM or on disk, but I was wondering about the reasoning why to
blow it up that much?
Is there any reasoning behind writing these as extensive tables from colprof
in Argyll?
Guy
$ iccdump -t A2B0 other_profile.icc
Lut16:
Input Channels = 3
Output Channels = 3
CLUT resolution = 17
Input Table entries = 2
Output Table entries = 2
XYZ matrix = 1.000000, 0.000000, 0.000000
0.000000, 1.000000, 0.000000
0.000000, 0.000000, 1.000000
$ iccdump -v 3 -t A2B0 other_profile.icc
[... major snippage ...]
Input table:
0: 0.0000000000 0.0000000000 0.0000000000
1: 1.0000000000 1.0000000000 1.0000000000
[... more snippage ...]
Output table:
0: 0.0000000000 0.0000000000 0.0000000000
1: 1.0000000000 1.0000000000 1.0000000000
--
Guy K. Kloss
Institute of Information and Mathematical Sciences
Te Kura Pūtaiao o Mōhiohio me Pāngarau
Massey University, Albany (North Shore City, Auckland)
473 State Highway 17, Gate 1, Mailroom, Quad B Building
voice: +64 9 414-0800 ext. 9585 fax: +64 9 441-8181
G.Kloss@xxxxxxxxxxxx http://www.massey.ac.nz/~gkloss
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