[Openicc] Profile installation and association for Linux/Unix/X11

Tomas Carnecky tom at dbservice.com
Tue Apr 22 14:10:22 PDT 2008

Hal V. Engel wrote:
> On Monday 21 April 2008 12:22:05 Tomas Carnecky wrote:
>>  This whole discussion can be split up into two questions:
>>  1) Where to store the profiles
>>  2) Who is responsible for setting the _ICC_PROFILE property
> You missed one. Where is the configuration information that is needed to 
> manage the "loading" of profiles stored and how is that configuration 
> data managed? This might be part #2 but since this same question applies 
> to other devices like printers, scanners and cameras I don't think that 
> is the case since #2 is display device specific.

Ok. Do you want to have a central database with device/profile mappings
or should every device class manage its profile mappings on
its own? (Like, the xserver or session keeps one database, cups keeps
another etc).

>>  The only place that is
>>  common to all X clients is the xserver. If you want all clients to have
>>  a consistent view of available profiles, then registering them in the
>>  xserver is the only solution (I will probably have to do something like
>>  that for my GSoC project).
> I am not sure what you mean by registering them in the xserver?

I will have to write something that would allow X clients ask each other
whether they have access to a particular profile or not (if they run on
different hosts and having access to different filesystems). And I'm
thinking about allowing xclients share profiles through the xserver.
That would require a registry inside the xserver.

>>  a session is more likely run on different
>>  devices/xservers. In a large networked environment, the session would
>>  have to manage a big database of display device/profile mappings,
>>  whereas each xserver would only require one or two profiles for its
>>  display devices.
> Maybe more than one or two but more correctly one for each display 
> device that might be connected to the xserver. Which in most cases will 
> be one or two but for some machines might be a larger number (a laptop 
> that is used with projectors and multiple external monitors). But in any 
> case a fairly small number of display profiles.

That's what I meant. A xserver will see a small number of devices
compared to a session, thus requiring a smaller database.

>>  Does Windows/MacOS distinguish between color profiles and device
>>  profiles?
> There is no distinction made anywhere. Some profiles are for an abstract 
> non-existant device, for example sRGB or AdobeRGB. But the profiles we 
> are talking about are always for a specific device or at the very least 
> for a specific model of a device.
>>  IMHO it makes little sense to put a display device profile
>>  into a shared directory,
> I assume you mean a shared directory on the application host (xclient) 
> and not a shared directory on the xserver machine.

I wasn't aware that device profiles would be shared between xservers. I
always thought that a device profile is very specific to one particular
device and never shared. But you're right, there are profiles that are
valid for all devices of a given model, often supplied by the
manufacturer, so these profiles should be shared between all xservers
that have this model attached.


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