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

[Ross Burton]

On Thu, 2005-06-16 at 14:31 -0600, Chris Murphy wrote:
> 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.

The code isn't assuming Adobe RGB, but that is what I am testing it
with.

The EXIF ColorSpace tag only contains two values, "sRGB" or
"Uncalibrated".  If it is uncalibrated, then a profile can be created
from the WhitePoint and PrimaryChromatics properties.  This is what my
code does so far (I don't handle the sRGB case yet but that is trivial).

The next stage is to extract an embedded ICC profile (I need a tool to
embed a profile first as none of my JPEGs have one, any ideas?), and
then to look at PNG support.

-- 
Ross Burton                                 mail: ross at burtonini.com
                                          jabber: ross at burtonini.com
                                     www: http://www.burtonini.com./
 PGP Fingerprint: 1A21 F5B0 D8D0 CFE3 81D4 E25A 2D09 E447 D0B4 33DF