RGB and IHS controls

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#2817

From: Alan Walford
Date: Thu, 23 May 1991 16:38

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Anybody know the conversions between RGB (red, green, blue) and IHS
(intensity, hue, saturation) ?  I know this is asked in various news
groups from time to time but I can't seem to find it around.

When specifying colours with 3 sliders (like the palatte control does)
it is often more intuitive to have the user control I, H and S as opposed
to R,G and B.

I know the formulas look something like this (for NTSC at least):

  I = 0.299 R + 0.587 G + 0.114 B
  H =  ?    R +   ?   G +   ?   B
  S =  ?    R +   ?   G +   ?   B

  R =  ?    I +   ?   H +   ?   S
  G =  ?    I +   ?   H +   ?   S
  B =  ?    I +   ?   H +   ?   S

Can anyone complete these ?  

Thanks, Alan
aew@eosvcr.wimsey.bc.ca
----------------------------------------------------------------------------
Alan Walford                                             Tel:   604-731-0703
 ...uunet!van-bc!eosvcr!aew    OR
 aew@eosvcr.wimsey.bc.ca

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!van-bc!eosvcr!aew
From: aew@eosvcr.wimsey.bc.ca (Alan Walford)
Newsgroups: comp.windows.ms.programmer
Subject: RGB and IHS controls
Message-ID: <c3Re32w162w@eosvcr.wimsey.bc.ca>
Date: 23 May 91 16:38:11 GMT
Organization: Eos Systems Inc, Vancouver, B.C., Canada
Lines: 27