On Wednesday 11 January 2006 03:31 pm, Bob Friesenhahn wrote: snip > > It sounds like LPROF needs to handle all image data internally and > treat the operating system and widgets as a limited way to present > information. Avoid entrusting image data to something you don't have > direct control over. That is what ImageMagick & GraphicsMagick do. > I am sure it is what OpenEXR does. There is hardly any existing > display support for images with more than 8-bits per sample. Qt's > color picker widget would not have any way to display more accurate > colors to the user. Only recently are printing paths emerging which > pass more than 8-bits per sample to a printer. > > Work is under way to allow passing as much as 12 real bits to the > display via a digital interface but it may take a few years before > it is properly adopted. >
Yes I agree. I think what I need to do is to read the raw image data into a buffer and then use the offset information from the picker template to get the pixel data for each patch in the target from the raw data. Then QT becomes strictly for the UI and does not affect the profiling data in any way. Perhaps I need to have a look at ImageMagick to see how you are handling this. I am fairly sure that the 8 bit/channel data that QT is using is correct if you open an 8 bit image because I can't think of any reason for them to change the data. But todays better cameras and scanners all support 12 or more bits/channel of useful data. Also from looking at the actual rgb values that are in the QImage it appears to me that QT is doing more than just truncating the data when it is loading a 16 bit/channel image. It looks like the data is being compressed. This issue could also explain why profiles created using 16 bit/channel IT8 images with local convergence extrapolation turned on will exhibit local reversals in very dark highly saturated colors in 16 bit images. See http://sourceforge.net/tracker/index.php?func=detail&aid=1296658&group_id=146038&atid=764370 for details. I have been looking at this for some time trying to figure out what is causing it and have not figured out what is going on with it. Perhaps I now understand it better. I have also opened a bug report on this here http://sourceforge.net/tracker/index.php?func=detail&aid=1403455&group_id=146038&atid=764370 So if anyone has any ideas about how to approach this or any other possibly useful comments or information please post them in the bug report so that this can be tracked. Hal ------------------------------------------------------- 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
