Re: Color calibration in X
On Tue, Jan 16, 2001 at 01:18:42PM -0500, oliver <[EMAIL PROTECTED]> wrote: > Looking at Xcms manpages, I'm not entirely clear on what it's goal in life > is. It seems to lack any mechanism for converting arbitrary rgb data like a Well, you can convert rgb to other colourspaces (and vice versa and even weirder things), so it is certainly possible to do that. > > > That is, is it possible to do anything meaningful with > > ICCs under X? > Windows? Photoshop ;) I don't know what the focus of the gimp is, but color Windows has been ported to X? Any pointers? ;) (sorry, had to...) > I wonder what the impact would be on performance, ignoring Xcms stuff, to Why ignore Xcms? It is a fairl extensive API. under-used, maybe buggy, but nobody knows. > do a 3x3 matrix transform on every pixel before displaying it. With luts I > guess this amounts to three look ups and two adds per component per pixel, > or something like that, which seems pretty cheap. Patches welcome (oh yes). Also, "just grabbing icc profiles" is easier said than done, since there are a lot of patent issues around colour conversion/calibration/matching. -- -==- | ==-- _ | ---==---(_)__ __ __ Marc Lehmann +-- --==---/ / _ \/ // /\ \/ / [EMAIL PROTECTED] |e| -=/_/_//_/\_,_/ /_/\_\ XX11-RIPE --+ The choice of a GNU generation | |
RE: Color calibration in X
> However, you can calibrate your card/monitor combination and tell your > X-server about it, after which applications can query all neceessary > parameters (and do calulcations) with Xcms. Gimp does not > implement this > yet. > Well the calibration part is certainly a bit tricky, but beyond that the conversions seem a fairly straightforward thing to do. Not to mention something that is really necessary for any serious graphics work. > Hmm, how is this "added" gamma adjustment different to the gamma > adjustment in 3.x? ;) > Assumption based on the fact that xgamma is only present on the box I upgraded to 4.0 ... reminded of an old Benny Hill sketch somehow. > You can set them using properties on the root window, which Xcms > uses. Look for Xcms and XDCCC. > Looking at Xcms manpages, I'm not entirely clear on what it's goal in life is. It seems to lack any mechanism for converting arbitrary rgb data like a pixmap. Then again the X apis give me hives, so I'm probably missing something. Color space conversion of indivdual colors seems somewhat less then earth-shattering. > > That is, is it possible to do anything meaningful with > ICCs under X? > > Poissible, yes, but not in practice (I don't know of any programs that > evaluate icc profiles, and no useful program that evaluates these). Windows? Photoshop ;) I don't know what the focus of the gimp is, but color calibration would really be a nice addition. Certainly falls on the good side of cost / benefit. It would be cool to be able to take the TTF approach and just grab an ICC for a display from windows and plug it into the gimp, t least in the absence of color calibration tools for X I wonder what the impact would be on performance, ignoring Xcms stuff, to do a 3x3 matrix transform on every pixel before displaying it. With luts I guess this amounts to three look ups and two adds per component per pixel, or something like that, which seems pretty cheap. Cheers, ~ol
Re: Color calibration in X
On Fri, Jan 12, 2001 at 01:30:22PM -0500, oliver <[EMAIL PROTECTED]> wrote: > I was curious, how much support does X have for useful color calibration? A lot. It depends on the server, and xfree does not do much. Basically, the best you can do is to code it in your application. However, you can calibrate your card/monitor combination and tell your X-server about it, after which applications can query all neceessary parameters (and do calulcations) with Xcms. Gimp does not implement this yet. > I know that 4.0 adds gamma adjustment. Hmm, how is this "added" gamma adjustment different to the gamma adjustment in 3.x? ;) > What about the coordiantes of the white point and primaries? You can set them using properties on the root window, which Xcms uses. Look for Xcms and XDCCC. > That is, is it possible to do anything meaningful with ICCs under X? Poissible, yes, but not in practice (I don't know of any programs that evaluate icc profiles, and no useful program that evaluates these). -- -==- | ==-- _ | ---==---(_)__ __ __ Marc Lehmann +-- --==---/ / _ \/ // /\ \/ / [EMAIL PROTECTED] |e| -=/_/_//_/\_,_/ /_/\_\ XX11-RIPE --+ The choice of a GNU generation | |
