On Fri, 2 Dec 2005, Joris wrote:
A similar need arises when looking at it from the point of view of these 'many more image viewers'. Many people, like myself and I guess for example Bob with GraphicsMagick (right, Bob?), first group a few decoders, next find themselves in need of color handling and image editing handling, and group a few encoders in the package, and end up with such an image viewer/browser/editor/converter. Next, the need arises to improve the decoding of files with embedded ICC profiles. It is not desirable to rewrite the whole of the color handling stuff in such case, since the thing works exactly as the designer intended,
There is also the problem that the vast majority of image file formats don't support ICC color profiles and don't have a well-defined color space. Some formats have a very well defined color space but don't know anything about ICC color profiles. With a swiss army knife, there are many sharp edges, and it is easy to get cut unless great care is taken.
So when GraphicsMagick reads a YCbCr DPX file in BT.709 space, it would be really nice to simply attach the BT.709 YCbCr profile as provided in the the lcms profiles collection, but without a clear specification for the target colorspace (so the correct profile can be selected), conversion to some random non-YCbCr space fails. The correct answer is definitely not "just assume sRGB". So instead, we use our own transformation matrix to BT.709 RGB and simply hope for the best.
Bob ====================================== Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click _______________________________________________ Lcms-user mailing list Lcms-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lcms-user
