[Openicc] Proof of concept, storing profile in X atoms

[Chris Murphy]

On Jun 16, 2005, at 10:47 AM, Ross Burton wrote:

> Hi,
>
> I've been investigating colour management recently, mainly as the  
> photos
> from my digital camera are in the Adobe RGB colour space and thus look
> washed out when viewed on my sRGB display.
>
> By reading this list and poking a bit I've got a trial implementation,
> where an application at startup sets an ICC profile on a property  
> of the
> root window (as discussed on this list).  The atom I am using is
> _ICC_PROFILE (format is 32-bit cardinals).  Applications can then  
> obtain
> this profile and use it to adjust images as required, to demonstrate
> this I've patched the GNOME image viewer Eye Of Gnome.  It's so far
> working quite well, so would appreciate some feedback on my approach,
> and am wondering if there is any possibility of this atom being  
> drafted
> as a freedesktop.org standard, if there isn't another standard for  
> this
> I'm unaware of.

It sounds like the app is going to assume Adobe RGB (1998) as a  
source profile. This isn't a good assumption, unless the images are  
actually Adobe RGB (1998) images.

It would be better to parse the file on open for EXIF metadata, and  
check the colorspace tag. Whatever its set to, use that as the source  
profile, and then grab the current display profile (or short of that  
just use sRGB) as the destination, and convert on-the-fly to achieve  
display compensation.

Also, the app needs to check for an ICC profile and defer to that, if  
present, instead of EXIF.



Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
-------------------------------------------------------------
Co-author "Real World Color Management, 2nd Edition"
Published by PeachPit Press (ISBN 0-321-26722-2)