Re: Color calibration in X

2001-01-17 Thread Marc Lehmann

On Tue, Jan 16, 2001 at 01:18:42PM -0500, oliver [EMAIL PROTECTED] wrote:
   Looking at Xcms manpages, I'm not entirely clear on what it's goal in life
 is. It seems to lack any mechanism for converting arbitrary rgb data like a

Well, you can convert rgb to other colourspaces (and vice versa and even
weirder things), so it is certainly possible to do that.

 That is, is it possible to do anything meaningful with
  ICCs under X?

   Windows? Photoshop ;) I don't know what the focus of the gimp is, but color

Windows has been ported to X? Any pointers? ;) (sorry, had to...)

   I wonder what the impact would be on performance, ignoring Xcms stuff, to

Why ignore Xcms? It is a fairl extensive API. under-used, maybe buggy, but
nobody knows.

 do a 3x3 matrix transform on every pixel before displaying it. With luts I
 guess this amounts to three look ups and two adds per component per pixel,
 or something like that, which seems pretty cheap.

Patches welcome (oh yes). Also, "just grabbing icc profiles" is easier
said than done, since there are a lot of patent issues around colour
conversion/calibration/matching.

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RE: Color calibration in X

2001-01-16 Thread oliver

 However, you can calibrate your card/monitor combination and tell your
 X-server about it, after which applications can query all neceessary
 parameters (and do calulcations) with Xcms. Gimp does not
 implement this
 yet.


Well the calibration part is certainly a bit tricky, but beyond that the
conversions seem a fairly straightforward thing to do. Not to mention
something that is really necessary for any serious graphics work.

 Hmm, how is this "added" gamma adjustment different to the gamma
 adjustment in 3.x? ;)


Assumption based on the fact that xgamma is only present on the box I
upgraded to 4.0 ... reminded of an old Benny Hill sketch somehow.

 You can set them using properties on the root window, which Xcms
 uses. Look for Xcms and XDCCC.


Looking at Xcms manpages, I'm not entirely clear on what it's goal in life
is. It seems to lack any mechanism for converting arbitrary rgb data like a
pixmap. Then again the X apis give me hives, so I'm probably missing
something. Color space conversion of indivdual colors seems somewhat less
then earth-shattering.

  That is, is it possible to do anything meaningful with
 ICCs under X?

 Poissible, yes, but not in practice (I don't know of any programs that
 evaluate icc profiles, and no useful program that evaluates these).

Windows? Photoshop ;) I don't know what the focus of the gimp is, but color
calibration would really be a nice addition. Certainly falls on the good
side of cost / benefit. It would be cool to be able to take the TTF approach
and just grab an ICC for a display from windows and plug it into the gimp, t
least in the absence of color calibration tools for X

I wonder what the impact would be on performance, ignoring Xcms stuff, to
do a 3x3 matrix transform on every pixel before displaying it. With luts I
guess this amounts to three look ups and two adds per component per pixel,
or something like that, which seems pretty cheap.


Cheers,
~ol




Re: Color calibration in X

2001-01-14 Thread Marc Lehmann

On Fri, Jan 12, 2001 at 01:30:22PM -0500, oliver [EMAIL PROTECTED] wrote:
   I was curious, how much support does X have for useful color calibration?

A lot. It depends on the server, and xfree does not do much. Basically, the
best you can do is to code it in your application.

However, you can calibrate your card/monitor combination and tell your
X-server about it, after which applications can query all neceessary
parameters (and do calulcations) with Xcms. Gimp does not implement this
yet.

   I know that 4.0 adds gamma adjustment.

Hmm, how is this "added" gamma adjustment different to the gamma
adjustment in 3.x? ;)

 What about the coordiantes of the white point and primaries?

You can set them using properties on the root window, which Xcms
uses. Look for Xcms and XDCCC.

   That is, is it possible to do anything meaningful with ICCs under X?

Poissible, yes, but not in practice (I don't know of any programs that
evaluate icc profiles, and no useful program that evaluates these).

-- 
  -==- |
  ==-- _   |
  ---==---(_)__  __   __   Marc Lehmann  +--
  --==---/ / _ \/ // /\ \/ /   [EMAIL PROTECTED] |e|
  -=/_/_//_/\_,_/ /_/\_\   XX11-RIPE --+
The choice of a GNU generation   |
 |



Color calibration in X

2001-01-12 Thread oliver

Hi,

I was curious, how much support does X have for useful color calibration?

I know that 4.0 adds gamma adjustment. What about the coordiantes of the
white point and primaries?

That is, is it possible to do anything meaningful with ICCs under X?

Cheers,
~ol
__
And that's the scary thing about this new system [the
renewed trend toward globalization]: it's Orwellian in
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