On 08/11/2016 06:31 AM, Marti Maria wrote: > > Hello Elle et al, > > I've been considering the case and here are some thoughts. > > I understand that when softproofing some "perfect" profiles would be nice > to return gamut clip, no matter the profile does not apply this clip in > unbounded mode. > > The amount of changes in lcms code to implement this is not trivial. > Actually, softproofing is implemented as a multiprofile transform with a > round trip of proofed profile in the middle. If the profile does not > introduce any artifact, then roundtrip is same and proofing does not show > any change. To implement what you ask for, I have to clip values before and > after this roundtrip. > There are some use cases lost if I do this change. Just imagine somebody > previewing which artifacts would get if using a certain embedded profile in > a floating point image file format. If the file format supports negatives > and highlights, the embedded profile would have no effect, and actually this > is what softproofing gives you: the right answer. After the modification you > ask for, the softproofing will return a gamut clip that the file format will > not suffer. Of course this may be just a corner case, but this is just a > sample. > > Anybody else on that? I would like to know what lcms users think and > eventually modify the behavior for next release.
Hi Marti, Thank you! very much! for considering the use case of soft proofing to a profile that supports unbounded conversions, and having the soft proofed channel values be clipped to show what the image will look like at integer precision. Given the use case you mention of converting to floating point where the user really does want to see the unclipped results, perhaps a flag to clip negative channel values (that could be used when soft proofing), and another flag to clip channel values >1.0? This would cover three different use cases: 1. the user doesn't want to clip; 2. the user only wants to clip negative channel values because the goal is to convert to a floating point file format that supports channel values > 1.0f but not negative channel values; 3. the user wants to convert to integer precision for output for printing or display on the web. Best regards, Elle ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports. http://sdm.link/zohodev2dev _______________________________________________ Lcms-user mailing list Lcms-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lcms-user
