Possible interaction between the Color manager and Argyllcms

[Richard Hughes]

On 27 July 2010 00:45, Leonard Evens <len at math.northwestern.edu> wrote:
> 1.  I am running Fedora 13.  dispwin used directly doesn't seem to do
> what it did previously.   I can use dispwin -I Profile_path  to install
> a profile, but it doesn't persist as it did under previous versions of
> Fedora (including Fedora 12).  But, I can use the gnome color manager to
> set the display profile, and that does seem topersist.

How do you mean persist? dispwin is probably trying to set the gamma
tables in xorg, which GPM is also trying to do. If you want to make
GCM just leave everything to argyll, just untick the color tickbox in
the GNOME session preferences.

> I wonder if the gnome color management is somehow interfering with way
> argyllcms ordinarily works.

As I understand it, dispwin runs, sets some values and then exits. GCM
runs gcm-apply at session start, and then also exits. If you run
gcm-prefs, the settings probably get re-applied. I think it's probably
a good idea to let GCM actually apply the profile, and use argyll to
create the profile. If you dump the generated icc profile somewhere
GCM knows about, that should work pretty well.

> 2.  In using the color manager to profile a laptop (running Ubuntu 10.4)
> screen, and using my Eye One Pro, I encountered some problems.  The
> Eye-One Pro has to be calibrated on its base, but the color manager
> doesn't ask me to do that.  In order to get it done, I have to press
> Details, which brings up the usual argyllcms command line interface.
> But it is not clear exactly what I am supposed to do using that
> interface and what using the color manager.

Ideally we can control the hardware using something other than a VTE
window. Using a VTE widget sucks as we always have to try and convert
the standard output to something localized and sane. Newer,
unreleased, versions of argyll allow us to set an environment variable
and get some easier to parse values, but there's no support in GCM for
that just yet, as we're waiting for a release. It's likely we just
have to add another screenscrape section to deal with the "Please
insert the device into the dock" type of thing. Screenscaping sucks,
but there's not a lot more we can do.

If you supply a "gcm-prefs --verbose" trace whilst you're calibrating
I can add the required screenscrape bits. I don't have the hardware
myself, although donations are always very welcome.

> Also,  the color manager didn't allow me to do any hardware calibration.
> Of course, for my laptop screen that is somewhat restricted---the only
> control is screen brightness.  I don't know what will happen when I try
> this an external monitor with lots of controls.  Perhaps I am just
> supposed  to continue in the Details window with argyllcms commands?

Do you mean monitors with a programmable LUT? We're aiming to support
these kind of things in the next few months. Monitors that allow
custom gamma ramps via DDC/CI are also interesting to me, although
specs on those are kinda hard to get.

Richard.