On Mar 26, 2016, at 3:39 AM, Graeme Gill <graeme2@argyllcms.com> wrote:
edward taffel wrote:
it seems that cmm code for performing transformations must be very similar across most implementations;
CMM != Profile creator.
yes, of course: i meant the algorithms applied by a configured fsm.
On Mar 25, 2016, at 11:14 AM, Ben Goren <ben@trumpetpower.com <mailto:ben@trumpetpower.com>> wrote:
ArgyllCMS is so far superior to anything and everything else out there
to what do you attribute this?
Graeme Gill, its author.
…
Graeme instead has put insane amounts of time into investigating edge cases, figuring out why this-or-that is close but not perfect, and so on.
such enthusiasm engenders interest.
Even in the execution of basic profile conversions, there is subtle room for differences. Is the implementation fixed point or floating point ? Is higher accuracy carried through each step of a transformation, or is it truncated at each step ? etc.
i gather then, you claim superior precision, & this may account for ben’s superior results; but, what of the ‘edge cases’ ben mentions? are these obviated by precision? i have found that colorsync may fail to match a color it reported out-of-gamut, i.e. transforms the coordinates, but the transformed color remains out-of-gamut. when i first encountered this [four years ago], claudio wilmanns made me aware of ‘edge conditions’; i tried to discover heuristics to cope—back-burner that! can you enlighten us as to the handling of ‘edge cases’? regards, edward
Even CMM's sometimes have some unexpected quirks - BPC for instance, or slope limits applied to power curves, etc.
Graeme Gill.
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