Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!zaphod.mps.ohio-state.edu!mips!prls!pyramid!leadsv!practic!polstra!jdp
From: jdp@polstra.UUCP (John Polstra)
Newsgroups: comp.windows.x
Subject: Do Servers Perform Gamma Correction?
Message-ID: <2803@polstra.UUCP>
Date: 16 Feb 90 23:50:21 GMT
Reply-To: jdp@polstra.UUCP (John Polstra)
Organization: Polstra & Co., Seattle
Lines: 16

The description of the XColor structure in the XLIB book seems to imply
that the RGB values correspond linearly to the intensities on the
display.  ("On full ... is a value of 65535 ... Half brightness is a
value of 32767 ...")  Do the various servers attempt to achieve
linearity via gamma correction or some similar scheme?  I looked in the
obvious places in the server sources but did not find any such
intensity correction.

Somebody (server or client) has to perform intensity correction, and it
seems clear that the server, which knows the characteristics of the
display, is the obvious choice.
-- 

-  John Polstra               jdp@polstra.UUCP
   Polstra & Co., Inc.        ...{uunet,sun}!practic!polstra!jdp
   Seattle, WA                (206) 932-6482